effective structure for a research paper

How To Write A Research Paper

Step-By-Step Tutorial With Examples + FREE Template

By: Derek Jansen (MBA) | Expert Reviewer: Dr Eunice Rautenbach | March 2024

For many students, crafting a strong research paper from scratch can feel like a daunting task – and rightly so! In this post, we’ll unpack what a research paper is, what it needs to do , and how to write one – in three easy steps. 🙂 

Overview: Writing A Research Paper

What (exactly) is a research paper.

• How to write a research paper
• Stage 1 : Topic & literature search
• Stage 2 : Structure & outline
• Stage 3 : Iterative writing
• Key takeaways

Let’s start by asking the most important question, “ What is a research paper? ”.

Simply put, a research paper is a scholarly written work where the writer (that’s you!) answers a specific question (this is called a research question ) through evidence-based arguments . Evidence-based is the keyword here. In other words, a research paper is different from an essay or other writing assignments that draw from the writer’s personal opinions or experiences. With a research paper, it’s all about building your arguments based on evidence (we’ll talk more about that evidence a little later).

Now, it’s worth noting that there are many different types of research papers , including analytical papers (the type I just described), argumentative papers, and interpretative papers. Here, we’ll focus on analytical papers , as these are some of the most common – but if you’re keen to learn about other types of research papers, be sure to check out the rest of the blog .

With that basic foundation laid, let’s get down to business and look at how to write a research paper .

Overview: The 3-Stage Process

While there are, of course, many potential approaches you can take to write a research paper, there are typically three stages to the writing process. So, in this tutorial, we’ll present a straightforward three-step process that we use when working with students at Grad Coach.

These three steps are:

• Finding a research topic and reviewing the existing literature
• Developing a provisional structure and outline for your paper, and
• Writing up your initial draft and then refining it iteratively

Let’s dig into each of these.

Need a helping hand?

Step 1: Find a topic and review the literature

As we mentioned earlier, in a research paper, you, as the researcher, will try to answer a question . More specifically, that’s called a research question , and it sets the direction of your entire paper. What’s important to understand though is that you’ll need to answer that research question with the help of high-quality sources – for example, journal articles, government reports, case studies, and so on. We’ll circle back to this in a minute.

The first stage of the research process is deciding on what your research question will be and then reviewing the existing literature (in other words, past studies and papers) to see what they say about that specific research question. In some cases, your professor may provide you with a predetermined research question (or set of questions). However, in many cases, you’ll need to find your own research question within a certain topic area.

Finding a strong research question hinges on identifying a meaningful research gap – in other words, an area that’s lacking in existing research. There’s a lot to unpack here, so if you wanna learn more, check out the plain-language explainer video below.

Once you’ve figured out which question (or questions) you’ll attempt to answer in your research paper, you’ll need to do a deep dive into the existing literature – this is called a “ literature search ”. Again, there are many ways to go about this, but your most likely starting point will be Google Scholar .

If you’re new to Google Scholar, think of it as Google for the academic world. You can start by simply entering a few different keywords that are relevant to your research question and it will then present a host of articles for you to review. What you want to pay close attention to here is the number of citations for each paper – the more citations a paper has, the more credible it is (generally speaking – there are some exceptions, of course).

Ideally, what you’re looking for are well-cited papers that are highly relevant to your topic. That said, keep in mind that citations are a cumulative metric , so older papers will often have more citations than newer papers – just because they’ve been around for longer. So, don’t fixate on this metric in isolation – relevance and recency are also very important.

Beyond Google Scholar, you’ll also definitely want to check out academic databases and aggregators such as Science Direct, PubMed, JStor and so on. These will often overlap with the results that you find in Google Scholar, but they can also reveal some hidden gems – so, be sure to check them out.

Once you’ve worked your way through all the literature, you’ll want to catalogue all this information in some sort of spreadsheet so that you can easily recall who said what, when and within what context. If you’d like, we’ve got a free literature spreadsheet that helps you do exactly that.

Step 2: Develop a structure and outline

With your research question pinned down and your literature digested and catalogued, it’s time to move on to planning your actual research paper .

It might sound obvious, but it’s really important to have some sort of rough outline in place before you start writing your paper. So often, we see students eagerly rushing into the writing phase, only to land up with a disjointed research paper that rambles on in multiple

Now, the secret here is to not get caught up in the fine details . Realistically, all you need at this stage is a bullet-point list that describes (in broad strokes) what you’ll discuss and in what order. It’s also useful to remember that you’re not glued to this outline – in all likelihood, you’ll chop and change some sections once you start writing, and that’s perfectly okay. What’s important is that you have some sort of roadmap in place from the start.

At this stage you might be wondering, “ But how should I structure my research paper? ”. Well, there’s no one-size-fits-all solution here, but in general, a research paper will consist of a few relatively standardised components:

• Introduction
• Literature review
• Methodology

Let’s take a look at each of these.

First up is the introduction section . As the name suggests, the purpose of the introduction is to set the scene for your research paper. There are usually (at least) four ingredients that go into this section – these are the background to the topic, the research problem and resultant research question , and the justification or rationale. If you’re interested, the video below unpacks the introduction section in more detail. 

The next section of your research paper will typically be your literature review . Remember all that literature you worked through earlier? Well, this is where you’ll present your interpretation of all that content . You’ll do this by writing about recent trends, developments, and arguments within the literature – but more specifically, those that are relevant to your research question . The literature review can oftentimes seem a little daunting, even to seasoned researchers, so be sure to check out our extensive collection of literature review content here .

With the introduction and lit review out of the way, the next section of your paper is the research methodology . In a nutshell, the methodology section should describe to your reader what you did (beyond just reviewing the existing literature) to answer your research question. For example, what data did you collect, how did you collect that data, how did you analyse that data and so on? For each choice, you’ll also need to justify why you chose to do it that way, and what the strengths and weaknesses of your approach were.

Now, it’s worth mentioning that for some research papers, this aspect of the project may be a lot simpler . For example, you may only need to draw on secondary sources (in other words, existing data sets). In some cases, you may just be asked to draw your conclusions from the literature search itself (in other words, there may be no data analysis at all). But, if you are required to collect and analyse data, you’ll need to pay a lot of attention to the methodology section. The video below provides an example of what the methodology section might look like.

By this stage of your paper, you will have explained what your research question is, what the existing literature has to say about that question, and how you analysed additional data to try to answer your question. So, the natural next step is to present your analysis of that data . This section is usually called the “results” or “analysis” section and this is where you’ll showcase your findings.

Depending on your school’s requirements, you may need to present and interpret the data in one section – or you might split the presentation and the interpretation into two sections. In the latter case, your “results” section will just describe the data, and the “discussion” is where you’ll interpret that data and explicitly link your analysis back to your research question. If you’re not sure which approach to take, check in with your professor or take a look at past papers to see what the norms are for your programme.

Alright – once you’ve presented and discussed your results, it’s time to wrap it up . This usually takes the form of the “ conclusion ” section. In the conclusion, you’ll need to highlight the key takeaways from your study and close the loop by explicitly answering your research question. Again, the exact requirements here will vary depending on your programme (and you may not even need a conclusion section at all) – so be sure to check with your professor if you’re unsure.

Step 3: Write and refine

Finally, it’s time to get writing. All too often though, students hit a brick wall right about here… So, how do you avoid this happening to you?

Well, there’s a lot to be said when it comes to writing a research paper (or any sort of academic piece), but we’ll share three practical tips to help you get started.

First and foremost , it’s essential to approach your writing as an iterative process. In other words, you need to start with a really messy first draft and then polish it over multiple rounds of editing. Don’t waste your time trying to write a perfect research paper in one go. Instead, take the pressure off yourself by adopting an iterative approach.

Secondly , it’s important to always lean towards critical writing , rather than descriptive writing. What does this mean? Well, at the simplest level, descriptive writing focuses on the “ what ”, while critical writing digs into the “ so what ” – in other words, the implications . If you’re not familiar with these two types of writing, don’t worry! You can find a plain-language explanation here.

Last but not least, you’ll need to get your referencing right. Specifically, you’ll need to provide credible, correctly formatted citations for the statements you make. We see students making referencing mistakes all the time and it costs them dearly. The good news is that you can easily avoid this by using a simple reference manager . If you don’t have one, check out our video about Mendeley, an easy (and free) reference management tool that you can start using today.

Recap: Key Takeaways

We’ve covered a lot of ground here. To recap, the three steps to writing a high-quality research paper are:

• To choose a research question and review the literature
• To plan your paper structure and draft an outline
• To take an iterative approach to writing, focusing on critical writing and strong referencing

Remember, this is just a b ig-picture overview of the research paper development process and there’s a lot more nuance to unpack. So, be sure to grab a copy of our free research paper template to learn more about how to write a research paper.

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How to Write a Research Paper

Use the links below to jump directly to any section of this guide:

Research Paper Fundamentals

How to choose a topic or question, how to create a working hypothesis or thesis, common research paper methodologies, how to gather and organize evidence , how to write an outline for your research paper, how to write a rough draft, how to revise your draft, how to produce a final draft, resources for teachers .

It is not fair to say that no one writes anymore. Just about everyone writes text messages, brief emails, or social media posts every single day. Yet, most people don't have a lot of practice with the formal, organized writing required for a good academic research paper. This guide contains links to a variety of resources that can help demystify the process. Some of these resources are intended for teachers; they contain exercises, activities, and teaching strategies. Other resources are intended for direct use by students who are struggling to write papers, or are looking for tips to make the process go more smoothly.

The resources in this section are designed to help students understand the different types of research papers, the general research process, and how to manage their time. Below, you'll find links from university writing centers, the trusted Purdue Online Writing Lab, and more.

What is an Academic Research Paper?

"Genre and the Research Paper" (Purdue OWL)

There are different types of research papers. Different types of scholarly questions will lend themselves to one format or another. This is a brief introduction to the two main genres of research paper: analytic and argumentative. 

"7 Most Popular Types of Research Papers" (Personal-writer.com)

This resource discusses formats that high school students commonly encounter, such as the compare and contrast essay and the definitional essay. Please note that the inclusion of this link is not an endorsement of this company's paid service.

How to Prepare and Plan Out Writing a Research Paper

Teachers can give their students a step-by-step guide like these to help them understand the different steps of the research paper process. These guides can be combined with the time management tools in the next subsection to help students come up with customized calendars for completing their papers.

"Ten Steps for Writing Research Papers" (American University)  

This resource from American University is a comprehensive guide to the research paper writing process, and includes examples of proper research questions and thesis topics.

"Steps in Writing a Research Paper" (SUNY Empire State College)

This guide breaks the research paper process into 11 steps. Each "step" links to a separate page, which describes the work entailed in completing it.

How to Manage Time Effectively

The links below will help students determine how much time is necessary to complete a paper. If your sources are not available online or at your local library, you'll need to leave extra time for the Interlibrary Loan process. Remember that, even if you do not need to consult secondary sources, you'll still need to leave yourself ample time to organize your thoughts.

"Research Paper Planner: Timeline" (Baylor University)

This interactive resource from Baylor University creates a suggested writing schedule based on how much time a student has to work on the assignment.

"Research Paper Planner" (UCLA)

UCLA's library offers this step-by-step guide to the research paper writing process, which also includes a suggested planning calendar.

There's a reason teachers spend a long time talking about choosing a good topic. Without a good topic and a well-formulated research question, it is almost impossible to write a clear and organized paper. The resources below will help you generate ideas and formulate precise questions.

"How to Select a Research Topic" (Univ. of Michigan-Flint)

This resource is designed for college students who are struggling to come up with an appropriate topic. A student who uses this resource and still feels unsure about his or her topic should consult the course instructor for further personalized assistance.

"25 Interesting Research Paper Topics to Get You Started" (Kibin)

This resource, which is probably most appropriate for high school students, provides a list of specific topics to help get students started. It is broken into subsections, such as "paper topics on local issues."

"Writing a Good Research Question" (Grand Canyon University)

This introduction to research questions includes some embedded videos, as well as links to scholarly articles on research questions. This resource would be most appropriate for teachers who are planning lessons on research paper fundamentals.

"How to Write a Research Question the Right Way" (Kibin)

This student-focused resource provides more detail on writing research questions. The language is accessible, and there are embedded videos and examples of good and bad questions.

It is important to have a rough hypothesis or thesis in mind at the beginning of the research process. People who have a sense of what they want to say will have an easier time sorting through scholarly sources and other information. The key, of course, is not to become too wedded to the draft hypothesis or thesis. Just about every working thesis gets changed during the research process.

CrashCourse Video: "Sociology Research Methods" (YouTube)

Although this video is tailored to sociology students, it is applicable to students in a variety of social science disciplines. This video does a good job demonstrating the connection between the brainstorming that goes into selecting a research question and the formulation of a working hypothesis.

"How to Write a Thesis Statement for an Analytical Essay" (YouTube)

Students writing analytical essays will not develop the same type of working hypothesis as students who are writing research papers in other disciplines. For these students, developing the working thesis may happen as a part of the rough draft (see the relevant section below). 

"Research Hypothesis" (Oakland Univ.)

This resource provides some examples of hypotheses in social science disciplines like Political Science and Criminal Justice. These sample hypotheses may also be useful for students in other soft social sciences and humanities disciplines like History.

When grading a research paper, instructors look for a consistent methodology. This section will help you understand different methodological approaches used in research papers. Students will get the most out of these resources if they use them to help prepare for conversations with teachers or discussions in class.

"Types of Research Designs" (USC)

A "research design," used for complex papers, is related to the paper's method. This resource contains introductions to a variety of popular research designs in the social sciences. Although it is not the most intuitive site to read, the information here is very valuable. 

"Major Research Methods" (YouTube)

Although this video is a bit on the dry side, it provides a comprehensive overview of the major research methodologies in a format that might be more accessible to students who have struggled with textbooks or other written resources.

"Humanities Research Strategies" (USC)

This is a portal where students can learn about four methodological approaches for humanities papers: Historical Methodologies, Textual Criticism, Conceptual Analysis, and the Synoptic method.

"Selected Major Social Science Research Methods: Overview" (National Academies Press)

This appendix from the book  Using Science as Evidence in Public Policy , printed by National Academies Press, introduces some methods used in social science papers.

"Organizing Your Social Sciences Research Paper: 6. The Methodology" (USC)

This resource from the University of Southern California's library contains tips for writing a methodology section in a research paper.

How to Determine the Best Methodology for You

Anyone who is new to writing research papers should be sure to select a method in consultation with their instructor. These resources can be used to help prepare for that discussion. They may also be used on their own by more advanced students.

"Choosing Appropriate Research Methodologies" (Palgrave Study Skills)

This friendly and approachable resource from Palgrave Macmillan can be used by students who are just starting to think about appropriate methodologies.

"How to Choose Your Research Methods" (NFER (UK))

This is another approachable resource students can use to help narrow down the most appropriate methods for their research projects.

The resources in this section introduce the process of gathering scholarly sources and collecting evidence. You'll find a range of material here, from introductory guides to advanced explications best suited to college students. Please consult the LitCharts  How to Do Academic Research guide for a more comprehensive list of resources devoted to finding scholarly literature.

Google Scholar

Students who have access to library websites with detailed research guides should start there, but people who do not have access to those resources can begin their search for secondary literature here.

"Gathering Appropriate Information" (Texas Gateway)

This resource from the Texas Gateway for online resources introduces students to the research process, and contains interactive exercises. The level of complexity is suitable for middle school, high school, and introductory college classrooms.

"An Overview of Quantitative and Qualitative Data Collection Methods" (NSF)

This PDF from the National Science Foundation goes into detail about best practices and pitfalls in data collection across multiple types of methodologies.

"Social Science Methods for Data Collection and Analysis" (Swiss FIT)

This resource is appropriate for advanced undergraduates or teachers looking to create lessons on research design and data collection. It covers techniques for gathering data via interviews, observations, and other methods.

"Collecting Data by In-depth Interviewing" (Leeds Univ.)

This resource contains enough information about conducting interviews to make it useful for teachers who want to create a lesson plan, but is also accessible enough for college juniors or seniors to make use of it on their own.

There is no "one size fits all" outlining technique. Some students might devote all their energy and attention to the outline in order to avoid the paper. Other students may benefit from being made to sit down and organize their thoughts into a lengthy sentence outline. The resources in this section include strategies and templates for multiple types of outlines. 

"Topic vs. Sentence Outlines" (UC Berkeley)

This resource introduces two basic approaches to outlining: the shorter topic-based approach, and the longer, more detailed sentence-based approach. This resource also contains videos on how to develop paper paragraphs from the sentence-based outline.

"Types of Outlines and Samples" (Purdue OWL)

The Purdue Online Writing Lab's guide is a slightly less detailed discussion of different types of outlines. It contains several sample outlines.

"Writing An Outline" (Austin C.C.)

This resource from a community college contains sample outlines from an American history class that students can use as models.

"How to Structure an Outline for a College Paper" (YouTube)

This brief (sub-2 minute) video from the ExpertVillage YouTube channel provides a model of outline writing for students who are struggling with the idea.

"Outlining" (Harvard)

This is a good resource to consult after completing a draft outline. It offers suggestions for making sure your outline avoids things like unnecessary repetition.

As with outlines, rough drafts can take on many different forms. These resources introduce teachers and students to the various approaches to writing a rough draft. This section also includes resources that will help you cite your sources appropriately according to the MLA, Chicago, and APA style manuals.

"Creating a Rough Draft for a Research Paper" (Univ. of Minnesota)

This resource is useful for teachers in particular, as it provides some suggested exercises to help students with writing a basic rough draft. 

Rough Draft Assignment (Duke of Definition)

This sample assignment, with a brief list of tips, was developed by a high school teacher who runs a very successful and well-reviewed page of educational resources.

"Creating the First Draft of Your Research Paper" (Concordia Univ.)

This resource will be helpful for perfectionists or procrastinators, as it opens by discussing the problem of avoiding writing. It also provides a short list of suggestions meant to get students writing.

Using Proper Citations

There is no such thing as a rough draft of a scholarly citation. These links to the three major citation guides will ensure that your citations follow the correct format. Please consult the LitCharts How to Cite Your Sources guide for more resources.

Chicago Manual of Style Citation Guide

Some call  The Chicago Manual of Style , which was first published in 1906, "the editors' Bible." The manual is now in its 17th edition, and is popular in the social sciences, historical journals, and some other fields in the humanities.

APA Citation Guide

According to the American Psychological Association, this guide was developed to aid reading comprehension, clarity of communication, and to reduce bias in language in the social and behavioral sciences. Its first full edition was published in 1952, and it is now in its sixth edition.

MLA Citation Guide

The Modern Language Association style is used most commonly within the liberal arts and humanities. The  MLA Style Manual and Guide to Scholarly Publishing  was first published in 1985 and (as of 2008) is in its third edition.

Any professional scholar will tell you that the best research papers are made in the revision stage. No matter how strong your research question or working thesis, it is not possible to write a truly outstanding paper without devoting energy to revision. These resources provide examples of revision exercises for the classroom, as well as tips for students working independently.

"The Art of Revision" (Univ. of Arizona)

This resource provides a wealth of information and suggestions for both students and teachers. There is a list of suggested exercises that teachers might use in class, along with a revision checklist that is useful for teachers and students alike.

"Script for Workshop on Revision" (Vanderbilt University)

Vanderbilt's guide for leading a 50-minute revision workshop can serve as a model for teachers who wish to guide students through the revision process during classtime. 

"Revising Your Paper" (Univ. of Washington)

This detailed handout was designed for students who are beginning the revision process. It discusses different approaches and methods for revision, and also includes a detailed list of things students should look for while they revise.

"Revising Drafts" (UNC Writing Center)

This resource is designed for students and suggests things to look for during the revision process. It provides steps for the process and has a FAQ for students who have questions about why it is important to revise.

Conferencing with Writing Tutors and Instructors

No writer is so good that he or she can't benefit from meeting with instructors or peer tutors. These resources from university writing, learning, and communication centers provide suggestions for how to get the most out of these one-on-one meetings.

"Getting Feedback" (UNC Writing Center)

This very helpful resource talks about how to ask for feedback during the entire writing process. It contains possible questions that students might ask when developing an outline, during the revision process, and after the final draft has been graded.

"Prepare for Your Tutoring Session" (Otis College of Art and Design)

This guide from a university's student learning center contains a lot of helpful tips for getting the most out of working with a writing tutor.

"The Importance of Asking Your Professor" (Univ. of Waterloo)

This article from the university's Writing and Communication Centre's blog contains some suggestions for how and when to get help from professors and Teaching Assistants.

Once you've revised your first draft, you're well on your way to handing in a polished paper. These resources—each of them produced by writing professionals at colleges and universities—outline the steps required in order to produce a final draft. You'll find proofreading tips and checklists in text and video form.

"Developing a Final Draft of a Research Paper" (Univ. of Minnesota)

While this resource contains suggestions for revision, it also features a couple of helpful checklists for the last stages of completing a final draft.

Basic Final Draft Tips and Checklist (Univ. of Maryland-University College)

This short and accessible resource, part of UMUC's very thorough online guide to writing and research, contains a very basic checklist for students who are getting ready to turn in their final drafts.

Final Draft Checklist (Everett C.C.)

This is another accessible final draft checklist, appropriate for both high school and college students. It suggests reading your essay aloud at least once.

"How to Proofread Your Final Draft" (YouTube)

This video (approximately 5 minutes), produced by Eastern Washington University, gives students tips on proofreading final drafts.

"Proofreading Tips" (Georgia Southern-Armstrong)

This guide will help students learn how to spot common errors in their papers. It suggests focusing on content and editing for grammar and mechanics.

This final set of resources is intended specifically for high school and college instructors. It provides links to unit plans and classroom exercises that can help improve students' research and writing skills. You'll find resources that give an overview of the process, along with activities that focus on how to begin and how to carry out research. 

"Research Paper Complete Resources Pack" (Teachers Pay Teachers)

This packet of assignments, rubrics, and other resources is designed for high school students. The resources in this packet are aligned to Common Core standards.

"Research Paper—Complete Unit" (Teachers Pay Teachers)

This packet of assignments, notes, PowerPoints, and other resources has a 4/4 rating with over 700 ratings. It is designed for high school teachers, but might also be useful to college instructors who work with freshmen.

"Teaching Students to Write Good Papers" (Yale)

This resource from Yale's Center for Teaching and Learning is designed for college instructors, and it includes links to appropriate activities and exercises.

"Research Paper Writing: An Overview" (CUNY Brooklyn)

CUNY Brooklyn offers this complete lesson plan for introducing students to research papers. It includes an accompanying set of PowerPoint slides.

"Lesson Plan: How to Begin Writing a Research Paper" (San Jose State Univ.)

This lesson plan is designed for students in the health sciences, so teachers will have to modify it for their own needs. It includes a breakdown of the brainstorming, topic selection, and research question process. 

"Quantitative Techniques for Social Science Research" (Univ. of Pittsburgh)

This is a set of PowerPoint slides that can be used to introduce students to a variety of quantitative methods used in the social sciences.

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Structure of a Research Paper: Tips to Improve Your Manuscript

You’ve spent months or years conducting your academic research. Now it’s time to write your journal article. For some, this can become a daunting task because writing is not their forte. It might become difficult to even start writing. However, once you organize your thoughts and begin writing them down, the overall task will become easier.

We provide some helpful tips for you here.

Organize Your Thoughts

Perhaps one of the most important tasks before you even begin to write is to get organized. By this point, your data is compiled and analyzed. You most likely also have many pages of “notes”. These must also be organized. Fortunately, this is much easier to do than in the past with hand-written notes. Presuming that these tasks are completed, what’s next?

Related: Ready with your title and looking forward to manuscript submission ? Check these journal selection guidelines  now!

When suggesting that you organize your thoughts, we mean to take a look at what you have compiled. Ask yourself what you are trying to convey to the reader. What is the most important message from your research? How will your results affect others? Is more research necessary?

Write your answers down and keep them where you can see them while writing. This will help you focus on your goals.

Aim for Clarity

Your paper should be presented as clearly as possible. You want your readers to understand your research. You also do not want them to stop reading because the text is too technical.

Keep in mind that your published research will be available in academic journals all over the world. This means that people of different languages will read it. Moreover, even with scientists, this could present a language barrier. According to a recent article , always remember the following points as you write:

• Clarity : Cleary define terms; avoid nonrelevant information.
• Simplicity : Keep sentence structure simple and direct.
• Accuracy : Represent all data and illustrations accurately.

For example, consider the following sentence:

“Chemical x had an effect on metabolism.”

This is an ambiguous statement. It does not tell the reader much. State the results instead:

“Chemical x increased fat metabolism by 20 percent.”

All scientific research also provide significance of findings, usually presented as defined “P” values. Be sure to explain these findings using descriptive terms. For example, rather than using the words “ significant effect ,” use a more descriptive term, such as “ significant increase .”

For more tips, please also see “Tips and Techniques for Scientific Writing”. In addition, it is very important to have your paper edited by a native English speaking professional editor. There are many editing services available for academic manuscripts and publication support services.

Research Paper Structure

With the above in mind, you can now focus on structure. Scientific papers are organized into specific sections and each has a goal. We have listed them here.

• Your title is the most important part of your paper. It draws the reader in and tells them what you are presenting. Moreover, if you think about the titles of papers that you might browse in a day and which papers you actually read, you’ll agree.
• The title should be clear and interesting otherwise the reader will not continue reading.
• Authors’ names and affiliations are on the title page.
• The abstract is a summary of your research. It is nearly as important as the title because the reader will be able to quickly read through it.
• Most journals, the abstract can become divided into very short sections to guide the reader through the summaries.
• Keep the sentences short and focused.
• Avoid acronyms and citations.
• Include background information on the subject and your objectives here.
• Describe the materials used and include the names and locations of the manufacturers.
• For any animal studies, include where you obtained the animals and a statement of humane treatment.
• Clearly and succinctly explain your methods so that it can be duplicated.
• Criteria for inclusion and exclusion in the study and statistical analyses should be included.
• Discuss your findings here.
• Be careful to not make definitive statements .
• Your results suggest that something is or is not true.
• This is true even when your results prove your hypothesis.
• Discuss what your results mean in this section.
• Discuss any study limitations. Suggest additional studies.
• Acknowledge all contributors.
• All citations in the text must have a corresponding reference.
• Check your author guidelines for format protocols.
• In most cases, your tables and figures appear at the end of your paper or in a separate file.
• The titles (legends) usually become listed after the reference section.
• Be sure that you define each acronym and abbreviation in each table and figure.

Helpful Rules

In their article entitled, “Ten simple rules for structuring papers,” in PLOS Computational Biology , authors Mensh and Kording provided 10 helpful tips as follows:

• Focus on a central contribution.
• Write for those who do not know your work.
• Use the “context-content-conclusion” approach.
• Avoid superfluous information and use parallel structures.
• Summarize your research in the abstract.
• Explain the importance of your research in the introduction.
• Explain your results in a logical sequence and support them with figures and tables.
• Discuss any data gaps and limitations.
• Allocate your time for the most important sections.
• Get feedback from colleagues.

Some of these rules have been briefly discussed above; however, the study done by the authors does provide detailed explanations on all of them.

Helpful Sites

Visit the following links for more helpful information:

• “ Some writing tips for scientific papers ”
• “ How to Structure Your Dissertation ”
• “ Conciseness in Academic Writing: How to Prune Sentences ”
• “ How to Optimize Sentence Length in Academic Writing ”

So, do you follow any additional tips when structuring your research paper ? Share them with us in the comments below!

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How to write your first research paper.

Writing a research manuscript is an intimidating process for many novice writers in the sciences. One of the stumbling blocks is the beginning of the process and creating the first draft. This paper presents guidelines on how to initiate the writing process and draft each section of a research manuscript. The paper discusses seven rules that allow the writer to prepare a well-structured and comprehensive manuscript for a publication submission. In addition, the author lists different strategies for successful revision. Each of those strategies represents a step in the revision process and should help the writer improve the quality of the manuscript. The paper could be considered a brief manual for publication.

It is late at night. You have been struggling with your project for a year. You generated an enormous amount of interesting data. Your pipette feels like an extension of your hand, and running western blots has become part of your daily routine, similar to brushing your teeth. Your colleagues think you are ready to write a paper, and your lab mates tease you about your “slow” writing progress. Yet days pass, and you cannot force yourself to sit down to write. You have not written anything for a while (lab reports do not count), and you feel you have lost your stamina. How does the writing process work? How can you fit your writing into a daily schedule packed with experiments? What section should you start with? What distinguishes a good research paper from a bad one? How should you revise your paper? These and many other questions buzz in your head and keep you stressed. As a result, you procrastinate. In this paper, I will discuss the issues related to the writing process of a scientific paper. Specifically, I will focus on the best approaches to start a scientific paper, tips for writing each section, and the best revision strategies.

1. Schedule your writing time in Outlook

Whether you have written 100 papers or you are struggling with your first, starting the process is the most difficult part unless you have a rigid writing schedule. Writing is hard. It is a very difficult process of intense concentration and brain work. As stated in Hayes’ framework for the study of writing: “It is a generative activity requiring motivation, and it is an intellectual activity requiring cognitive processes and memory” [ 1 ]. In his book How to Write a Lot: A Practical Guide to Productive Academic Writing , Paul Silvia says that for some, “it’s easier to embalm the dead than to write an article about it” [ 2 ]. Just as with any type of hard work, you will not succeed unless you practice regularly. If you have not done physical exercises for a year, only regular workouts can get you into good shape again. The same kind of regular exercises, or I call them “writing sessions,” are required to be a productive author. Choose from 1- to 2-hour blocks in your daily work schedule and consider them as non-cancellable appointments. When figuring out which blocks of time will be set for writing, you should select the time that works best for this type of work. For many people, mornings are more productive. One Yale University graduate student spent a semester writing from 8 a.m. to 9 a.m. when her lab was empty. At the end of the semester, she was amazed at how much she accomplished without even interrupting her regular lab hours. In addition, doing the hardest task first thing in the morning contributes to the sense of accomplishment during the rest of the day. This positive feeling spills over into our work and life and has a very positive effect on our overall attitude.

Rule 1: Create regular time blocks for writing as appointments in your calendar and keep these appointments.

2. start with an outline.

Now that you have scheduled time, you need to decide how to start writing. The best strategy is to start with an outline. This will not be an outline that you are used to, with Roman numerals for each section and neat parallel listing of topic sentences and supporting points. This outline will be similar to a template for your paper. Initially, the outline will form a structure for your paper; it will help generate ideas and formulate hypotheses. Following the advice of George M. Whitesides, “. . . start with a blank piece of paper, and write down, in any order, all important ideas that occur to you concerning the paper” [ 3 ]. Use Table 1 as a starting point for your outline. Include your visuals (figures, tables, formulas, equations, and algorithms), and list your findings. These will constitute the first level of your outline, which will eventually expand as you elaborate.

The next stage is to add context and structure. Here you will group all your ideas into sections: Introduction, Methods, Results, and Discussion/Conclusion ( Table 2 ). This step will help add coherence to your work and sift your ideas.

Now that you have expanded your outline, you are ready for the next step: discussing the ideas for your paper with your colleagues and mentor. Many universities have a writing center where graduate students can schedule individual consultations and receive assistance with their paper drafts. Getting feedback during early stages of your draft can save a lot of time. Talking through ideas allows people to conceptualize and organize thoughts to find their direction without wasting time on unnecessary writing. Outlining is the most effective way of communicating your ideas and exchanging thoughts. Moreover, it is also the best stage to decide to which publication you will submit the paper. Many people come up with three choices and discuss them with their mentors and colleagues. Having a list of journal priorities can help you quickly resubmit your paper if your paper is rejected.

Rule 2: Create a detailed outline and discuss it with your mentor and peers.

3. continue with drafts.

After you get enough feedback and decide on the journal you will submit to, the process of real writing begins. Copy your outline into a separate file and expand on each of the points, adding data and elaborating on the details. When you create the first draft, do not succumb to the temptation of editing. Do not slow down to choose a better word or better phrase; do not halt to improve your sentence structure. Pour your ideas into the paper and leave revision and editing for later. As Paul Silvia explains, “Revising while you generate text is like drinking decaffeinated coffee in the early morning: noble idea, wrong time” [ 2 ].

Many students complain that they are not productive writers because they experience writer’s block. Staring at an empty screen is frustrating, but your screen is not really empty: You have a template of your article, and all you need to do is fill in the blanks. Indeed, writer’s block is a logical fallacy for a scientist ― it is just an excuse to procrastinate. When scientists start writing a research paper, they already have their files with data, lab notes with materials and experimental designs, some visuals, and tables with results. All they need to do is scrutinize these pieces and put them together into a comprehensive paper.

3.1. Starting with Materials and Methods

If you still struggle with starting a paper, then write the Materials and Methods section first. Since you have all your notes, it should not be problematic for you to describe the experimental design and procedures. Your most important goal in this section is to be as explicit as possible by providing enough detail and references. In the end, the purpose of this section is to allow other researchers to evaluate and repeat your work. So do not run into the same problems as the writers of the sentences in (1):

1a. Bacteria were pelleted by centrifugation. 1b. To isolate T cells, lymph nodes were collected.

As you can see, crucial pieces of information are missing: the speed of centrifuging your bacteria, the time, and the temperature in (1a); the source of lymph nodes for collection in (b). The sentences can be improved when information is added, as in (2a) and (2b), respectfully:

2a. Bacteria were pelleted by centrifugation at 3000g for 15 min at 25°C. 2b. To isolate T cells, mediastinal and mesenteric lymph nodes from Balb/c mice were collected at day 7 after immunization with ovabumin.

If your method has previously been published and is well-known, then you should provide only the literature reference, as in (3a). If your method is unpublished, then you need to make sure you provide all essential details, as in (3b).

3a. Stem cells were isolated, according to Johnson [23]. 3b. Stem cells were isolated using biotinylated carbon nanotubes coated with anti-CD34 antibodies.

Furthermore, cohesion and fluency are crucial in this section. One of the malpractices resulting in disrupted fluency is switching from passive voice to active and vice versa within the same paragraph, as shown in (4). This switching misleads and distracts the reader.

4. Behavioral computer-based experiments of Study 1 were programmed by using E-Prime. We took ratings of enjoyment, mood, and arousal as the patients listened to preferred pleasant music and unpreferred music by using Visual Analogue Scales (SI Methods). The preferred and unpreferred status of the music was operationalized along a continuum of pleasantness [ 4 ].

The problem with (4) is that the reader has to switch from the point of view of the experiment (passive voice) to the point of view of the experimenter (active voice). This switch causes confusion about the performer of the actions in the first and the third sentences. To improve the coherence and fluency of the paragraph above, you should be consistent in choosing the point of view: first person “we” or passive voice [ 5 ]. Let’s consider two revised examples in (5).

5a. We programmed behavioral computer-based experiments of Study 1 by using E-Prime. We took ratings of enjoyment, mood, and arousal by using Visual Analogue Scales (SI Methods) as the patients listened to preferred pleasant music and unpreferred music. We operationalized the preferred and unpreferred status of the music along a continuum of pleasantness. 5b. Behavioral computer-based experiments of Study 1 were programmed by using E-Prime. Ratings of enjoyment, mood, and arousal were taken as the patients listened to preferred pleasant music and unpreferred music by using Visual Analogue Scales (SI Methods). The preferred and unpreferred status of the music was operationalized along a continuum of pleasantness.

If you choose the point of view of the experimenter, then you may end up with repetitive “we did this” sentences. For many readers, paragraphs with sentences all beginning with “we” may also sound disruptive. So if you choose active sentences, you need to keep the number of “we” subjects to a minimum and vary the beginnings of the sentences [ 6 ].

Interestingly, recent studies have reported that the Materials and Methods section is the only section in research papers in which passive voice predominantly overrides the use of the active voice [ 5 , 7 , 8 , 9 ]. For example, Martínez shows a significant drop in active voice use in the Methods sections based on the corpus of 1 million words of experimental full text research articles in the biological sciences [ 7 ]. According to the author, the active voice patterned with “we” is used only as a tool to reveal personal responsibility for the procedural decisions in designing and performing experimental work. This means that while all other sections of the research paper use active voice, passive voice is still the most predominant in Materials and Methods sections.

Writing Materials and Methods sections is a meticulous and time consuming task requiring extreme accuracy and clarity. This is why when you complete your draft, you should ask for as much feedback from your colleagues as possible. Numerous readers of this section will help you identify the missing links and improve the technical style of this section.

Rule 3: Be meticulous and accurate in describing the Materials and Methods. Do not change the point of view within one paragraph.

3.2. writing results section.

For many authors, writing the Results section is more intimidating than writing the Materials and Methods section . If people are interested in your paper, they are interested in your results. That is why it is vital to use all your writing skills to objectively present your key findings in an orderly and logical sequence using illustrative materials and text.

Your Results should be organized into different segments or subsections where each one presents the purpose of the experiment, your experimental approach, data including text and visuals (tables, figures, schematics, algorithms, and formulas), and data commentary. For most journals, your data commentary will include a meaningful summary of the data presented in the visuals and an explanation of the most significant findings. This data presentation should not repeat the data in the visuals, but rather highlight the most important points. In the “standard” research paper approach, your Results section should exclude data interpretation, leaving it for the Discussion section. However, interpretations gradually and secretly creep into research papers: “Reducing the data, generalizing from the data, and highlighting scientific cases are all highly interpretive processes. It should be clear by now that we do not let the data speak for themselves in research reports; in summarizing our results, we interpret them for the reader” [ 10 ]. As a result, many journals including the Journal of Experimental Medicine and the Journal of Clinical Investigation use joint Results/Discussion sections, where results are immediately followed by interpretations.

Another important aspect of this section is to create a comprehensive and supported argument or a well-researched case. This means that you should be selective in presenting data and choose only those experimental details that are essential for your reader to understand your findings. You might have conducted an experiment 20 times and collected numerous records, but this does not mean that you should present all those records in your paper. You need to distinguish your results from your data and be able to discard excessive experimental details that could distract and confuse the reader. However, creating a picture or an argument should not be confused with data manipulation or falsification, which is a willful distortion of data and results. If some of your findings contradict your ideas, you have to mention this and find a plausible explanation for the contradiction.

In addition, your text should not include irrelevant and peripheral information, including overview sentences, as in (6).

6. To show our results, we first introduce all components of experimental system and then describe the outcome of infections.

Indeed, wordiness convolutes your sentences and conceals your ideas from readers. One common source of wordiness is unnecessary intensifiers. Adverbial intensifiers such as “clearly,” “essential,” “quite,” “basically,” “rather,” “fairly,” “really,” and “virtually” not only add verbosity to your sentences, but also lower your results’ credibility. They appeal to the reader’s emotions but lower objectivity, as in the common examples in (7):

7a. Table 3 clearly shows that … 7b. It is obvious from figure 4 that …

Another source of wordiness is nominalizations, i.e., nouns derived from verbs and adjectives paired with weak verbs including “be,” “have,” “do,” “make,” “cause,” “provide,” and “get” and constructions such as “there is/are.”

8a. We tested the hypothesis that there is a disruption of membrane asymmetry. 8b. In this paper we provide an argument that stem cells repopulate injured organs.

In the sentences above, the abstract nominalizations “disruption” and “argument” do not contribute to the clarity of the sentences, but rather clutter them with useless vocabulary that distracts from the meaning. To improve your sentences, avoid unnecessary nominalizations and change passive verbs and constructions into active and direct sentences.

9a. We tested the hypothesis that the membrane asymmetry is disrupted. 9b. In this paper we argue that stem cells repopulate injured organs.

Your Results section is the heart of your paper, representing a year or more of your daily research. So lead your reader through your story by writing direct, concise, and clear sentences.

Rule 4: Be clear, concise, and objective in describing your Results.

3.3. now it is time for your introduction.

Now that you are almost half through drafting your research paper, it is time to update your outline. While describing your Methods and Results, many of you diverged from the original outline and re-focused your ideas. So before you move on to create your Introduction, re-read your Methods and Results sections and change your outline to match your research focus. The updated outline will help you review the general picture of your paper, the topic, the main idea, and the purpose, which are all important for writing your introduction.

The best way to structure your introduction is to follow the three-move approach shown in Table 3 .

Adapted from Swales and Feak [ 11 ].

The moves and information from your outline can help to create your Introduction efficiently and without missing steps. These moves are traffic signs that lead the reader through the road of your ideas. Each move plays an important role in your paper and should be presented with deep thought and care. When you establish the territory, you place your research in context and highlight the importance of your research topic. By finding the niche, you outline the scope of your research problem and enter the scientific dialogue. The final move, “occupying the niche,” is where you explain your research in a nutshell and highlight your paper’s significance. The three moves allow your readers to evaluate their interest in your paper and play a significant role in the paper review process, determining your paper reviewers.

Some academic writers assume that the reader “should follow the paper” to find the answers about your methodology and your findings. As a result, many novice writers do not present their experimental approach and the major findings, wrongly believing that the reader will locate the necessary information later while reading the subsequent sections [ 5 ]. However, this “suspense” approach is not appropriate for scientific writing. To interest the reader, scientific authors should be direct and straightforward and present informative one-sentence summaries of the results and the approach.

Another problem is that writers understate the significance of the Introduction. Many new researchers mistakenly think that all their readers understand the importance of the research question and omit this part. However, this assumption is faulty because the purpose of the section is not to evaluate the importance of the research question in general. The goal is to present the importance of your research contribution and your findings. Therefore, you should be explicit and clear in describing the benefit of the paper.

The Introduction should not be long. Indeed, for most journals, this is a very brief section of about 250 to 600 words, but it might be the most difficult section due to its importance.

Rule 5: Interest your reader in the Introduction section by signalling all its elements and stating the novelty of the work.

3.4. discussion of the results.

For many scientists, writing a Discussion section is as scary as starting a paper. Most of the fear comes from the variation in the section. Since every paper has its unique results and findings, the Discussion section differs in its length, shape, and structure. However, some general principles of writing this section still exist. Knowing these rules, or “moves,” can change your attitude about this section and help you create a comprehensive interpretation of your results.

The purpose of the Discussion section is to place your findings in the research context and “to explain the meaning of the findings and why they are important, without appearing arrogant, condescending, or patronizing” [ 11 ]. The structure of the first two moves is almost a mirror reflection of the one in the Introduction. In the Introduction, you zoom in from general to specific and from the background to your research question; in the Discussion section, you zoom out from the summary of your findings to the research context, as shown in Table 4 .

Adapted from Swales and Feak and Hess [ 11 , 12 ].

The biggest challenge for many writers is the opening paragraph of the Discussion section. Following the moves in Table 1 , the best choice is to start with the study’s major findings that provide the answer to the research question in your Introduction. The most common starting phrases are “Our findings demonstrate . . .,” or “In this study, we have shown that . . .,” or “Our results suggest . . .” In some cases, however, reminding the reader about the research question or even providing a brief context and then stating the answer would make more sense. This is important in those cases where the researcher presents a number of findings or where more than one research question was presented. Your summary of the study’s major findings should be followed by your presentation of the importance of these findings. One of the most frequent mistakes of the novice writer is to assume the importance of his findings. Even if the importance is clear to you, it may not be obvious to your reader. Digesting the findings and their importance to your reader is as crucial as stating your research question.

Another useful strategy is to be proactive in the first move by predicting and commenting on the alternative explanations of the results. Addressing potential doubts will save you from painful comments about the wrong interpretation of your results and will present you as a thoughtful and considerate researcher. Moreover, the evaluation of the alternative explanations might help you create a logical step to the next move of the discussion section: the research context.

The goal of the research context move is to show how your findings fit into the general picture of the current research and how you contribute to the existing knowledge on the topic. This is also the place to discuss any discrepancies and unexpected findings that may otherwise distort the general picture of your paper. Moreover, outlining the scope of your research by showing the limitations, weaknesses, and assumptions is essential and adds modesty to your image as a scientist. However, make sure that you do not end your paper with the problems that override your findings. Try to suggest feasible explanations and solutions.

If your submission does not require a separate Conclusion section, then adding another paragraph about the “take-home message” is a must. This should be a general statement reiterating your answer to the research question and adding its scientific implications, practical application, or advice.

Just as in all other sections of your paper, the clear and precise language and concise comprehensive sentences are vital. However, in addition to that, your writing should convey confidence and authority. The easiest way to illustrate your tone is to use the active voice and the first person pronouns. Accompanied by clarity and succinctness, these tools are the best to convince your readers of your point and your ideas.

Rule 6: Present the principles, relationships, and generalizations in a concise and convincing tone.

4. choosing the best working revision strategies.

Now that you have created the first draft, your attitude toward your writing should have improved. Moreover, you should feel more confident that you are able to accomplish your project and submit your paper within a reasonable timeframe. You also have worked out your writing schedule and followed it precisely. Do not stop ― you are only at the midpoint from your destination. Just as the best and most precious diamond is no more than an unattractive stone recognized only by trained professionals, your ideas and your results may go unnoticed if they are not polished and brushed. Despite your attempts to present your ideas in a logical and comprehensive way, first drafts are frequently a mess. Use the advice of Paul Silvia: “Your first drafts should sound like they were hastily translated from Icelandic by a non-native speaker” [ 2 ]. The degree of your success will depend on how you are able to revise and edit your paper.

The revision can be done at the macrostructure and the microstructure levels [ 13 ]. The macrostructure revision includes the revision of the organization, content, and flow. The microstructure level includes individual words, sentence structure, grammar, punctuation, and spelling.

The best way to approach the macrostructure revision is through the outline of the ideas in your paper. The last time you updated your outline was before writing the Introduction and the Discussion. Now that you have the beginning and the conclusion, you can take a bird’s-eye view of the whole paper. The outline will allow you to see if the ideas of your paper are coherently structured, if your results are logically built, and if the discussion is linked to the research question in the Introduction. You will be able to see if something is missing in any of the sections or if you need to rearrange your information to make your point.

The next step is to revise each of the sections starting from the beginning. Ideally, you should limit yourself to working on small sections of about five pages at a time [ 14 ]. After these short sections, your eyes get used to your writing and your efficiency in spotting problems decreases. When reading for content and organization, you should control your urge to edit your paper for sentence structure and grammar and focus only on the flow of your ideas and logic of your presentation. Experienced researchers tend to make almost three times the number of changes to meaning than novice writers [ 15 , 16 ]. Revising is a difficult but useful skill, which academic writers obtain with years of practice.

In contrast to the macrostructure revision, which is a linear process and is done usually through a detailed outline and by sections, microstructure revision is a non-linear process. While the goal of the macrostructure revision is to analyze your ideas and their logic, the goal of the microstructure editing is to scrutinize the form of your ideas: your paragraphs, sentences, and words. You do not need and are not recommended to follow the order of the paper to perform this type of revision. You can start from the end or from different sections. You can even revise by reading sentences backward, sentence by sentence and word by word.

One of the microstructure revision strategies frequently used during writing center consultations is to read the paper aloud [ 17 ]. You may read aloud to yourself, to a tape recorder, or to a colleague or friend. When reading and listening to your paper, you are more likely to notice the places where the fluency is disrupted and where you stumble because of a very long and unclear sentence or a wrong connector.

Another revision strategy is to learn your common errors and to do a targeted search for them [ 13 ]. All writers have a set of problems that are specific to them, i.e., their writing idiosyncrasies. Remembering these problems is as important for an academic writer as remembering your friends’ birthdays. Create a list of these idiosyncrasies and run a search for these problems using your word processor. If your problem is demonstrative pronouns without summary words, then search for “this/these/those” in your text and check if you used the word appropriately. If you have a problem with intensifiers, then search for “really” or “very” and delete them from the text. The same targeted search can be done to eliminate wordiness. Searching for “there is/are” or “and” can help you avoid the bulky sentences.

The final strategy is working with a hard copy and a pencil. Print a double space copy with font size 14 and re-read your paper in several steps. Try reading your paper line by line with the rest of the text covered with a piece of paper. When you are forced to see only a small portion of your writing, you are less likely to get distracted and are more likely to notice problems. You will end up spotting more unnecessary words, wrongly worded phrases, or unparallel constructions.

After you apply all these strategies, you are ready to share your writing with your friends, colleagues, and a writing advisor in the writing center. Get as much feedback as you can, especially from non-specialists in your field. Patiently listen to what others say to you ― you are not expected to defend your writing or explain what you wanted to say. You may decide what you want to change and how after you receive the feedback and sort it in your head. Even though some researchers make the revision an endless process and can hardly stop after a 14th draft; having from five to seven drafts of your paper is a norm in the sciences. If you can’t stop revising, then set a deadline for yourself and stick to it. Deadlines always help.

Rule 7: Revise your paper at the macrostructure and the microstructure level using different strategies and techniques. Receive feedback and revise again.

5. it is time to submit.

It is late at night again. You are still in your lab finishing revisions and getting ready to submit your paper. You feel happy ― you have finally finished a year’s worth of work. You will submit your paper tomorrow, and regardless of the outcome, you know that you can do it. If one journal does not take your paper, you will take advantage of the feedback and resubmit again. You will have a publication, and this is the most important achievement.

What is even more important is that you have your scheduled writing time that you are going to keep for your future publications, for reading and taking notes, for writing grants, and for reviewing papers. You are not going to lose stamina this time, and you will become a productive scientist. But for now, let’s celebrate the end of the paper.

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Primacy of the research question, structure of the paper, writing a research article: advice to beginners.

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Thomas V. Perneger, Patricia M. Hudelson, Writing a research article: advice to beginners, International Journal for Quality in Health Care , Volume 16, Issue 3, June 2004, Pages 191–192, https://doi.org/10.1093/intqhc/mzh053

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Writing research papers does not come naturally to most of us. The typical research paper is a highly codified rhetorical form [ 1 , 2 ]. Knowledge of the rules—some explicit, others implied—goes a long way toward writing a paper that will get accepted in a peer-reviewed journal.

A good research paper addresses a specific research question. The research question—or study objective or main research hypothesis—is the central organizing principle of the paper. Whatever relates to the research question belongs in the paper; the rest doesn’t. This is perhaps obvious when the paper reports on a well planned research project. However, in applied domains such as quality improvement, some papers are written based on projects that were undertaken for operational reasons, and not with the primary aim of producing new knowledge. In such cases, authors should define the main research question a posteriori and design the paper around it.

Generally, only one main research question should be addressed in a paper (secondary but related questions are allowed). If a project allows you to explore several distinct research questions, write several papers. For instance, if you measured the impact of obtaining written consent on patient satisfaction at a specialized clinic using a newly developed questionnaire, you may want to write one paper on the questionnaire development and validation, and another on the impact of the intervention. The idea is not to split results into ‘least publishable units’, a practice that is rightly decried, but rather into ‘optimally publishable units’.

What is a good research question? The key attributes are: (i) specificity; (ii) originality or novelty; and (iii) general relevance to a broad scientific community. The research question should be precise and not merely identify a general area of inquiry. It can often (but not always) be expressed in terms of a possible association between X and Y in a population Z, for example ‘we examined whether providing patients about to be discharged from the hospital with written information about their medications would improve their compliance with the treatment 1 month later’. A study does not necessarily have to break completely new ground, but it should extend previous knowledge in a useful way, or alternatively refute existing knowledge. Finally, the question should be of interest to others who work in the same scientific area. The latter requirement is more challenging for those who work in applied science than for basic scientists. While it may safely be assumed that the human genome is the same worldwide, whether the results of a local quality improvement project have wider relevance requires careful consideration and argument.

Once the research question is clearly defined, writing the paper becomes considerably easier. The paper will ask the question, then answer it. The key to successful scientific writing is getting the structure of the paper right. The basic structure of a typical research paper is the sequence of Introduction, Methods, Results, and Discussion (sometimes abbreviated as IMRAD). Each section addresses a different objective. The authors state: (i) the problem they intend to address—in other terms, the research question—in the Introduction; (ii) what they did to answer the question in the Methods section; (iii) what they observed in the Results section; and (iv) what they think the results mean in the Discussion.

In turn, each basic section addresses several topics, and may be divided into subsections (Table 1 ). In the Introduction, the authors should explain the rationale and background to the study. What is the research question, and why is it important to ask it? While it is neither necessary nor desirable to provide a full-blown review of the literature as a prelude to the study, it is helpful to situate the study within some larger field of enquiry. The research question should always be spelled out, and not merely left for the reader to guess.

Typical structure of a research paper

The Methods section should provide the readers with sufficient detail about the study methods to be able to reproduce the study if so desired. Thus, this section should be specific, concrete, technical, and fairly detailed. The study setting, the sampling strategy used, instruments, data collection methods, and analysis strategies should be described. In the case of qualitative research studies, it is also useful to tell the reader which research tradition the study utilizes and to link the choice of methodological strategies with the research goals [ 3 ].

The Results section is typically fairly straightforward and factual. All results that relate to the research question should be given in detail, including simple counts and percentages. Resist the temptation to demonstrate analytic ability and the richness of the dataset by providing numerous tables of non-essential results.

The Discussion section allows the most freedom. This is why the Discussion is the most difficult to write, and is often the weakest part of a paper. Structured Discussion sections have been proposed by some journal editors [ 4 ]. While strict adherence to such rules may not be necessary, following a plan such as that proposed in Table 1 may help the novice writer stay on track.

References should be used wisely. Key assertions should be referenced, as well as the methods and instruments used. However, unless the paper is a comprehensive review of a topic, there is no need to be exhaustive. Also, references to unpublished work, to documents in the grey literature (technical reports), or to any source that the reader will have difficulty finding or understanding should be avoided.

Having the structure of the paper in place is a good start. However, there are many details that have to be attended to while writing. An obvious recommendation is to read, and follow, the instructions to authors published by the journal (typically found on the journal’s website). Another concerns non-native writers of English: do have a native speaker edit the manuscript. A paper usually goes through several drafts before it is submitted. When revising a paper, it is useful to keep an eye out for the most common mistakes (Table 2 ). If you avoid all those, your paper should be in good shape.

Common mistakes seen in manuscripts submitted to this journal

Huth EJ . How to Write and Publish Papers in the Medical Sciences , 2nd edition. Baltimore, MD: Williams & Wilkins, 1990 .

Browner WS . Publishing and Presenting Clinical Research . Baltimore, MD: Lippincott, Williams & Wilkins, 1999 .

Devers KJ , Frankel RM. Getting qualitative research published. Educ Health 2001 ; 14 : 109 –117.

Docherty M , Smith R. The case for structuring the discussion of scientific papers. Br Med J 1999 ; 318 : 1224 –1225.

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Home » Research Paper Introduction – Writing Guide and Examples

Research Paper Introduction – Writing Guide and Examples

Table of Contents

Research Paper Introduction

Research paper introduction is the first section of a research paper that provides an overview of the study, its purpose, and the research question (s) or hypothesis (es) being investigated. It typically includes background information about the topic, a review of previous research in the field, and a statement of the research objectives. The introduction is intended to provide the reader with a clear understanding of the research problem, why it is important, and how the study will contribute to existing knowledge in the field. It also sets the tone for the rest of the paper and helps to establish the author’s credibility and expertise on the subject.

How to Write Research Paper Introduction

Writing an introduction for a research paper can be challenging because it sets the tone for the entire paper. Here are some steps to follow to help you write an effective research paper introduction:

• Start with a hook : Begin your introduction with an attention-grabbing statement, a question, or a surprising fact that will make the reader interested in reading further.
• Provide background information: After the hook, provide background information on the topic. This information should give the reader a general idea of what the topic is about and why it is important.
• State the research problem: Clearly state the research problem or question that the paper addresses. This should be done in a concise and straightforward manner.
• State the research objectives: After stating the research problem, clearly state the research objectives. This will give the reader an idea of what the paper aims to achieve.
• Provide a brief overview of the paper: At the end of the introduction, provide a brief overview of the paper. This should include a summary of the main points that will be discussed in the paper.
• Revise and refine: Finally, revise and refine your introduction to ensure that it is clear, concise, and engaging.

Structure of Research Paper Introduction

The following is a typical structure for a research paper introduction:

• Background Information: This section provides an overview of the topic of the research paper, including relevant background information and any previous research that has been done on the topic. It helps to give the reader a sense of the context for the study.
• Problem Statement: This section identifies the specific problem or issue that the research paper is addressing. It should be clear and concise, and it should articulate the gap in knowledge that the study aims to fill.
• Research Question/Hypothesis : This section states the research question or hypothesis that the study aims to answer. It should be specific and focused, and it should clearly connect to the problem statement.
• Significance of the Study: This section explains why the research is important and what the potential implications of the study are. It should highlight the contribution that the research makes to the field.
• Methodology: This section describes the research methods that were used to conduct the study. It should be detailed enough to allow the reader to understand how the study was conducted and to evaluate the validity of the results.
• Organization of the Paper : This section provides a brief overview of the structure of the research paper. It should give the reader a sense of what to expect in each section of the paper.

Research Paper Introduction Examples

Research Paper Introduction Examples could be:

Example 1: In recent years, the use of artificial intelligence (AI) has become increasingly prevalent in various industries, including healthcare. AI algorithms are being developed to assist with medical diagnoses, treatment recommendations, and patient monitoring. However, as the use of AI in healthcare grows, ethical concerns regarding privacy, bias, and accountability have emerged. This paper aims to explore the ethical implications of AI in healthcare and propose recommendations for addressing these concerns.

Example 2: Climate change is one of the most pressing issues facing our planet today. The increasing concentration of greenhouse gases in the atmosphere has resulted in rising temperatures, changing weather patterns, and other environmental impacts. In this paper, we will review the scientific evidence on climate change, discuss the potential consequences of inaction, and propose solutions for mitigating its effects.

Example 3: The rise of social media has transformed the way we communicate and interact with each other. While social media platforms offer many benefits, including increased connectivity and access to information, they also present numerous challenges. In this paper, we will examine the impact of social media on mental health, privacy, and democracy, and propose solutions for addressing these issues.

Example 4: The use of renewable energy sources has become increasingly important in the face of climate change and environmental degradation. While renewable energy technologies offer many benefits, including reduced greenhouse gas emissions and energy independence, they also present numerous challenges. In this paper, we will assess the current state of renewable energy technology, discuss the economic and political barriers to its adoption, and propose solutions for promoting the widespread use of renewable energy.

Purpose of Research Paper Introduction

The introduction section of a research paper serves several important purposes, including:

• Providing context: The introduction should give readers a general understanding of the topic, including its background, significance, and relevance to the field.
• Presenting the research question or problem: The introduction should clearly state the research question or problem that the paper aims to address. This helps readers understand the purpose of the study and what the author hopes to accomplish.
• Reviewing the literature: The introduction should summarize the current state of knowledge on the topic, highlighting the gaps and limitations in existing research. This shows readers why the study is important and necessary.
• Outlining the scope and objectives of the study: The introduction should describe the scope and objectives of the study, including what aspects of the topic will be covered, what data will be collected, and what methods will be used.
• Previewing the main findings and conclusions : The introduction should provide a brief overview of the main findings and conclusions that the study will present. This helps readers anticipate what they can expect to learn from the paper.

When to Write Research Paper Introduction

The introduction of a research paper is typically written after the research has been conducted and the data has been analyzed. This is because the introduction should provide an overview of the research problem, the purpose of the study, and the research questions or hypotheses that will be investigated.

Once you have a clear understanding of the research problem and the questions that you want to explore, you can begin to write the introduction. It’s important to keep in mind that the introduction should be written in a way that engages the reader and provides a clear rationale for the study. It should also provide context for the research by reviewing relevant literature and explaining how the study fits into the larger field of research.

Advantages of Research Paper Introduction

The introduction of a research paper has several advantages, including:

• Establishing the purpose of the research: The introduction provides an overview of the research problem, question, or hypothesis, and the objectives of the study. This helps to clarify the purpose of the research and provide a roadmap for the reader to follow.
• Providing background information: The introduction also provides background information on the topic, including a review of relevant literature and research. This helps the reader understand the context of the study and how it fits into the broader field of research.
• Demonstrating the significance of the research: The introduction also explains why the research is important and relevant. This helps the reader understand the value of the study and why it is worth reading.
• Setting expectations: The introduction sets the tone for the rest of the paper and prepares the reader for what is to come. This helps the reader understand what to expect and how to approach the paper.
• Grabbing the reader’s attention: A well-written introduction can grab the reader’s attention and make them interested in reading further. This is important because it can help to keep the reader engaged and motivated to read the rest of the paper.
• Creating a strong first impression: The introduction is the first part of the research paper that the reader will see, and it can create a strong first impression. A well-written introduction can make the reader more likely to take the research seriously and view it as credible.
• Establishing the author’s credibility: The introduction can also establish the author’s credibility as a researcher. By providing a clear and thorough overview of the research problem and relevant literature, the author can demonstrate their expertise and knowledge in the field.
• Providing a structure for the paper: The introduction can also provide a structure for the rest of the paper. By outlining the main sections and sub-sections of the paper, the introduction can help the reader navigate the paper and find the information they are looking for.

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Advanced Research Methods

Writing the research paper.

• What Is Research?
• Library Research
• Writing a Research Proposal

Before Writing the Paper

Methods, thesis and hypothesis, clarity, precision and academic expression, format your paper, typical problems, a few suggestions, avoid plagiarism.

• Presenting the Research Paper

Find a topic.

• Try to find a subject that really interests you.
• While you explore the topic, narrow or broaden your target and focus on something that gives the most promising results.
• Don't choose a huge subject if you have to write a 3 page long paper, and broaden your topic sufficiently if you have to submit at least 25 pages.
• Consult your class instructor (and your classmates) about the topic.

Explore the topic.

• Find primary and secondary sources in the library.
• Read and critically analyse them.
• Take notes.
• Compile surveys, collect data, gather materials for quantitative analysis (if these are good methods to investigate the topic more deeply).
• Come up with new ideas about the topic. Try to formulate your ideas in a few sentences.
• Review your notes and other materials and enrich the outline.
• Try to estimate how long the individual parts will be.
• Do others understand what you want to say?
• Do they accept it as new knowledge or relevant and important for a paper?
• Do they agree that your thoughts will result in a successful paper?
• Qualitative: gives answers on questions (how, why, when, who, what, etc.) by investigating an issue
• Quantitative:requires data and the analysis of data as well
• the essence, the point of the research paper in one or two sentences.
• a statement that can be proved or disproved.
• Be specific.
• Avoid ambiguity.
• Use predominantly the active voice, not the passive.
• Deal with one issue in one paragraph.
• Be accurate.
• Double-check your data, references, citations and statements.

Academic Expression

• Don't use familiar style or colloquial/slang expressions.
• Write in full sentences.
• Check the meaning of the words if you don't know exactly what they mean.
• Avoid metaphors.
• Almost the rough content of every paragraph.
• The order of the various topics in your paper.
• On the basis of the outline, start writing a part by planning the content, and then write it down.
• Put a visible mark (which you will later delete) where you need to quote a source, and write in the citation when you finish writing that part or a bigger part.
• Does the text make sense?
• Could you explain what you wanted?
• Did you write good sentences?
• Is there something missing?
• Check the spelling.
• Complete the citations, bring them in standard format.

Use the guidelines that your instructor requires (MLA, Chicago, APA, Turabian, etc.).

• Adjust margins, spacing, paragraph indentation, place of page numbers, etc.
• Standardize the bibliography or footnotes according to the guidelines.

• EndNote and EndNote Basic by UCLA Library Last Updated May 8, 2024 1074 views this year
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(Based on English Composition 2 from Illinois Valley Community College):

• Weak organization
• Poor support and development of ideas
• Weak use of secondary sources
• Excessive errors
• Stylistic weakness

When collecting materials, selecting research topic, and writing the paper:

• Be systematic and organized (e.g. keep your bibliography neat and organized; write your notes in a neat way, so that you can find them later on.
• Use your critical thinking ability when you read.
• Write down your thoughts (so that you can reconstruct them later).
• Stop when you have a really good idea and think about whether you could enlarge it to a whole research paper. If yes, take much longer notes.
• When you write down a quotation or summarize somebody else's thoughts in your notes or in the paper, cite the source (i.e. write down the author, title, publication place, year, page number).
• If you quote or summarize a thought from the internet, cite the internet source.
• Write an outline that is detailed enough to remind you about the content.
• Read your paper for yourself or, preferably, somebody else. 
• When you finish writing, check the spelling;
• Use the citation form (MLA, Chicago, or other) that your instructor requires and use it everywhere.

Plagiarism : somebody else's words or ideas presented without citation by an author

• Cite your source every time when you quote a part of somebody's work.
• Cite your source  every time when you summarize a thought from somebody's work.
• Cite your source  every time when you use a source (quote or summarize) from the Internet.

Consult the Citing Sources research guide for further details.

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How to Write a Research Paper Introduction (with Examples)

The research paper introduction section, along with the Title and Abstract, can be considered the face of any research paper. The following article is intended to guide you in organizing and writing the research paper introduction for a quality academic article or dissertation.

The research paper introduction aims to present the topic to the reader. A study will only be accepted for publishing if you can ascertain that the available literature cannot answer your research question. So it is important to ensure that you have read important studies on that particular topic, especially those within the last five to ten years, and that they are properly referenced in this section. 1 What should be included in the research paper introduction is decided by what you want to tell readers about the reason behind the research and how you plan to fill the knowledge gap. The best research paper introduction provides a systemic review of existing work and demonstrates additional work that needs to be done. It needs to be brief, captivating, and well-referenced; a well-drafted research paper introduction will help the researcher win half the battle.

The introduction for a research paper is where you set up your topic and approach for the reader. It has several key goals:

• Present your research topic
• Capture reader interest
• Summarize existing research
• Position your own approach
• Define your specific research problem and problem statement
• Highlight the novelty and contributions of the study
• Give an overview of the paper’s structure

The research paper introduction can vary in size and structure depending on whether your paper presents the results of original empirical research or is a review paper. Some research paper introduction examples are only half a page while others are a few pages long. In many cases, the introduction will be shorter than all of the other sections of your paper; its length depends on the size of your paper as a whole.

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Table of Contents

What is the introduction for a research paper, why is the introduction important in a research paper, craft a compelling introduction section with paperpal. try now, 1. introduce the research topic:, 2. determine a research niche:, 3. place your research within the research niche:, craft accurate research paper introductions with paperpal. start writing now, frequently asked questions on research paper introduction, key points to remember.

The introduction in a research paper is placed at the beginning to guide the reader from a broad subject area to the specific topic that your research addresses. They present the following information to the reader

• Scope: The topic covered in the research paper
• Context: Background of your topic
• Importance: Why your research matters in that particular area of research and the industry problem that can be targeted

The research paper introduction conveys a lot of information and can be considered an essential roadmap for the rest of your paper. A good introduction for a research paper is important for the following reasons:

• It stimulates your reader’s interest: A good introduction section can make your readers want to read your paper by capturing their interest. It informs the reader what they are going to learn and helps determine if the topic is of interest to them.
• It helps the reader understand the research background: Without a clear introduction, your readers may feel confused and even struggle when reading your paper. A good research paper introduction will prepare them for the in-depth research to come. It provides you the opportunity to engage with the readers and demonstrate your knowledge and authority on the specific topic.
• It explains why your research paper is worth reading: Your introduction can convey a lot of information to your readers. It introduces the topic, why the topic is important, and how you plan to proceed with your research.
• It helps guide the reader through the rest of the paper: The research paper introduction gives the reader a sense of the nature of the information that will support your arguments and the general organization of the paragraphs that will follow. It offers an overview of what to expect when reading the main body of your paper.

What are the parts of introduction in the research?

A good research paper introduction section should comprise three main elements: 2

• What is known: This sets the stage for your research. It informs the readers of what is known on the subject.
• What is lacking: This is aimed at justifying the reason for carrying out your research. This could involve investigating a new concept or method or building upon previous research.
• What you aim to do: This part briefly states the objectives of your research and its major contributions. Your detailed hypothesis will also form a part of this section.

How to write a research paper introduction?

The first step in writing the research paper introduction is to inform the reader what your topic is and why it’s interesting or important. This is generally accomplished with a strong opening statement. The second step involves establishing the kinds of research that have been done and ending with limitations or gaps in the research that you intend to address. Finally, the research paper introduction clarifies how your own research fits in and what problem it addresses. If your research involved testing hypotheses, these should be stated along with your research question. The hypothesis should be presented in the past tense since it will have been tested by the time you are writing the research paper introduction.

The following key points, with examples, can guide you when writing the research paper introduction section:

• Highlight the importance of the research field or topic
• Describe the background of the topic
• Present an overview of current research on the topic

Example: The inclusion of experiential and competency-based learning has benefitted electronics engineering education. Industry partnerships provide an excellent alternative for students wanting to engage in solving real-world challenges. Industry-academia participation has grown in recent years due to the need for skilled engineers with practical training and specialized expertise. However, from the educational perspective, many activities are needed to incorporate sustainable development goals into the university curricula and consolidate learning innovation in universities.

• Reveal a gap in existing research or oppose an existing assumption
• Formulate the research question

Example: There have been plausible efforts to integrate educational activities in higher education electronics engineering programs. However, very few studies have considered using educational research methods for performance evaluation of competency-based higher engineering education, with a focus on technical and or transversal skills. To remedy the current need for evaluating competencies in STEM fields and providing sustainable development goals in engineering education, in this study, a comparison was drawn between study groups without and with industry partners.

• State the purpose of your study
• Highlight the key characteristics of your study
• Describe important results
• Highlight the novelty of the study.
• Offer a brief overview of the structure of the paper.

Example: The study evaluates the main competency needed in the applied electronics course, which is a fundamental core subject for many electronics engineering undergraduate programs. We compared two groups, without and with an industrial partner, that offered real-world projects to solve during the semester. This comparison can help determine significant differences in both groups in terms of developing subject competency and achieving sustainable development goals.

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The purpose of the research paper introduction is to introduce the reader to the problem definition, justify the need for the study, and describe the main theme of the study. The aim is to gain the reader’s attention by providing them with necessary background information and establishing the main purpose and direction of the research.

The length of the research paper introduction can vary across journals and disciplines. While there are no strict word limits for writing the research paper introduction, an ideal length would be one page, with a maximum of 400 words over 1-4 paragraphs. Generally, it is one of the shorter sections of the paper as the reader is assumed to have at least a reasonable knowledge about the topic. 2 For example, for a study evaluating the role of building design in ensuring fire safety, there is no need to discuss definitions and nature of fire in the introduction; you could start by commenting upon the existing practices for fire safety and how your study will add to the existing knowledge and practice.

When deciding what to include in the research paper introduction, the rest of the paper should also be considered. The aim is to introduce the reader smoothly to the topic and facilitate an easy read without much dependency on external sources. 3 Below is a list of elements you can include to prepare a research paper introduction outline and follow it when you are writing the research paper introduction. Topic introduction: This can include key definitions and a brief history of the topic. Research context and background: Offer the readers some general information and then narrow it down to specific aspects. Details of the research you conducted: A brief literature review can be included to support your arguments or line of thought. Rationale for the study: This establishes the relevance of your study and establishes its importance. Importance of your research: The main contributions are highlighted to help establish the novelty of your study Research hypothesis: Introduce your research question and propose an expected outcome. Organization of the paper: Include a short paragraph of 3-4 sentences that highlights your plan for the entire paper

Cite only works that are most relevant to your topic; as a general rule, you can include one to three. Note that readers want to see evidence of original thinking. So it is better to avoid using too many references as it does not leave much room for your personal standpoint to shine through. Citations in your research paper introduction support the key points, and the number of citations depend on the subject matter and the point discussed. If the research paper introduction is too long or overflowing with citations, it is better to cite a few review articles rather than the individual articles summarized in the review. A good point to remember when citing research papers in the introduction section is to include at least one-third of the references in the introduction.

The literature review plays a significant role in the research paper introduction section. A good literature review accomplishes the following: Introduces the topic – Establishes the study’s significance – Provides an overview of the relevant literature – Provides context for the study using literature – Identifies knowledge gaps However, remember to avoid making the following mistakes when writing a research paper introduction: Do not use studies from the literature review to aggressively support your research Avoid direct quoting Do not allow literature review to be the focus of this section. Instead, the literature review should only aid in setting a foundation for the manuscript.

Remember the following key points for writing a good research paper introduction: 4

• Avoid stuffing too much general information: Avoid including what an average reader would know and include only that information related to the problem being addressed in the research paper introduction. For example, when describing a comparative study of non-traditional methods for mechanical design optimization, information related to the traditional methods and differences between traditional and non-traditional methods would not be relevant. In this case, the introduction for the research paper should begin with the state-of-the-art non-traditional methods and methods to evaluate the efficiency of newly developed algorithms.
• Avoid packing too many references: Cite only the required works in your research paper introduction. The other works can be included in the discussion section to strengthen your findings.
• Avoid extensive criticism of previous studies: Avoid being overly critical of earlier studies while setting the rationale for your study. A better place for this would be the Discussion section, where you can highlight the advantages of your method.
• Avoid describing conclusions of the study: When writing a research paper introduction remember not to include the findings of your study. The aim is to let the readers know what question is being answered. The actual answer should only be given in the Results and Discussion section.

To summarize, the research paper introduction section should be brief yet informative. It should convince the reader the need to conduct the study and motivate him to read further. If you’re feeling stuck or unsure, choose trusted AI academic writing assistants like Paperpal to effortlessly craft your research paper introduction and other sections of your research article.

1. Jawaid, S. A., & Jawaid, M. (2019). How to write introduction and discussion. Saudi Journal of Anaesthesia, 13(Suppl 1), S18.

2. Dewan, P., & Gupta, P. (2016). Writing the title, abstract and introduction: Looks matter!. Indian pediatrics, 53, 235-241.

3. Cetin, S., & Hackam, D. J. (2005). An approach to the writing of a scientific Manuscript1. Journal of Surgical Research, 128(2), 165-167.

4. Bavdekar, S. B. (2015). Writing introduction: Laying the foundations of a research paper. Journal of the Association of Physicians of India, 63(7), 44-6.

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Writing an Effective Research Paper: Structure & Content

Essential Guidelines for Structuring a Research Paper

Lecturer: kevin j. heintz, m.a. english.

This lecture was presented at ChungAng University in Seoul, South Korea in November 2018. Wordvice/Essay Review Managing Editor Kevin J. Heintz explains how to organize and compose a research manuscript that will get your study published in top journals.

Even researchers whose first language is English must learn some specific rules and follow some standard conventions when writing research papers. This takes a completely different skillset than essay writing or sending emails to your professors and friends, and therefore it is a good idea for every researcher to keep learning how to improve research writing.

Research is about more than just the scientific principles and discoveries you are making—it is about sharing these discoveries with fellow researchers and with the public. And to do this, researchers must publish their work in journals. Strong writing is key to making your research more accessible and powerful, and therefore this presentation is not about the rigors of research, but the demands of research writing. The methods and information in this lecture can be applied to almost any kind of research paper, although of course the exact structure and content will be somewhat determined by where you are submitting your research.

Lecture Content

• Overview of Research Paper Writing
• The Structure of a Research Paper
• Composing Your Paper Sections
• Tips for Improving Quality of Writing

*Quizzes are given throughout the lecture to test your comprehension and understanding.

Research Paper Structure Overview

“what should a research paper do”.

• Share the knowledge you have gained about a specific area of study with other researchers
• Show how your study fits into current science.
• Inform the public about important scientific activity.
• Explain clearly and succinctly the context of your study, including relevant literature (Introduction), the methods used for research and analysis (Methods), the findings of your study (Results), and the implications for these results and further research that might be needed (Discussion and Conclusion).

“What are the most important factors to consider when writing a research paper?”

The research you conduct should of course be novel, timely, rigorous, and hopefully interesting. But you must also transmit your scientific research into  writing —a well-written paper will greatly improve your chances of getting accepted into journals. Here is an overview of the factors that help create quality writing in a research paper:

• All of the parts of your paper should fit together in an order that makes sense.
• Include all necessary information in each section needed to understand the other sections.
• Do not repeat information unless it is necessary.
• Ensure that your sentences are grammatically and logically coherent.

Organization

• Most scientific papers follow the  IMRD  structure—be sure to put the right parts in the right section (e.g., don’t include the literature review in the Methods section).
• As you do research you will notice that there are a great many pieces of information and data you COULD include in your paper. However, you need to conform to length guidelines and keep your paper focused. Therefore, you should be sure that you are choosing a proper number of items to focus on for each section.
• For example, if your study has 10 results but your paper can only be 4,000 words, you might want to narrow down these results to only those that support your hypothesis, perhaps the 3-5 most important results.
• The same applies to the Introduction, where you must choose what background, context, and relevant literature to include. Be sure to only include information that gives readers a focused and relevant understanding of your area of study.
• Clarity is related to coherence, organization, and relevance. It means ensuring that each paragraph and sentence in your paper is natural and easy to read and understand: proper grammar, phrasing, and style are key to writing a paper that is readable and comprehensible to both experts and possibly non-experts, depending on your target audience.
• Perhaps the most important rule is to  conform to the formatting guidelines and other style conventions of the journal to which you are submitting.  Check the “GUIDE FOR AUTHORS” section of the journal or conference, or if the paper is for a class, ensure that you are using the proper formatting requirements. Here is one handy site:  OWL—Online Writing Lab at Purdue University

Research Paper Structure

The general structure of scientific research papers is IMR&D (Introduction, Methods, Results, and Discussion). The information moves from broad to specific to broad again as seen in this diagram, the Introduction and Discussion taking up the most room in your paper and the Methods and Results usually being the shortest ad most focused sections. However, the order in which you write your paper will not be the same as the final order of the information. Let’s first look briefly at what each section does and then discuss how to organize and compose your work.

Introduction Section

What does it do.

*Discusses the problem to be solved (purpose statement)

*Describes where your research fits into the current science (background and context)

*Uses primary literature with citations and summarizes the current understanding of the problem (“literature review”)

When do you write it?

*Write it last—after the conclusion and before the title and abstract

Methods Section

*Tells how you did the study—what materials and methods of research and analysis were used.

*First section you write—after preparing your figures and tables

Results Section

What does it do.

*Explains the important findings of your study that help to answer your research question or hypothesis and address your purpose statement.

*After the Methods and before the Discussion/Conclusion

Discussion/Conclusion Section

*Explains what your findings mean and what the implications and importance are both to your specific area of research and in a broader context (i.e., to the wider field or to society ).

*Includes limitations to your study and discusses possible future research that is needed to answer your research question more clearly and address closely related questions.

*After the Results Section and before the Introduction

Composing Your Research Paper Sections

This portion of the lecture focuses on developing techniques for composing your paper. You should always go back through your paper after one section is finished and correct or change another part, but by composing in this order you will be sure to include all of the important information. Not that the Methods and Results sections are written first. The reason for this is because you will not be changing or adding to these sections after you have evaluated your research—they represent the core data of your study.

Step 1: Prepare the figures and tables

Most likely, your research paper will use some figures, tables, or other graphics—they are also core data because they are usually numbers representing your findings and methods used. We won’t go into the details of how to prepare these here, but in the  Results section , we will go over how to write captions for the figures based on the data and research questions. For a detailed explanation of preparing and formatting figures, check out these sites (every journal will have their own formatting guidelines):

• Springer Online Research Resources
• ACSESS Digital Library (ASA, CSSA, and SSSA publications for reference)

Step 2: Write the Method s section

This section responds to the question  “How was the problem studied and analyzed?”

The Methods section should:

• Describe how an experiment was done
• Give a rationale for why specific experimental procedures were chosen
• Describe what was done to answer the research question and how it was done.
• Explain how the results were analyzed

Organization of Methods

Write the Methods section in this order to ensure proper organization and make it easier for readers to understand how your study was carried out:

• Description of materials used, including site and sample
• Explanation of how materials were prepared
• Explanation of how measurements were made and calculations performed
• Explanation of statistical methods to analyze data

Tips for the Methods Section

• Organize description of preparations, measurements, and protocol chronologically
• List the Methods in the same order as they will appear in the Results section
• Material should be organized by topic from most to least important
• Headings can be used to separated different results; paragraphs are often used instead

Step 3: Write the Results

This section responds to the question  “What did you find?”  Only the direct results of  your  research should be presented here, not any results from other studies. This is essentially an analysis of the data explained in sentence form so that it is easier to read and put into context.

The Results section should include:

• Findings presented in the same order as in the Methods section
• Data presented in tables, charts, graphs, and other figures (placed among research text or on a separate page)
• Reports on data collection, recruitment, and/or participants
• Data that corresponds to the central research question(s)
• Secondary findings (secondary outcomes, subgroup analyses, etc.)

Organization of Results

Write the Results in the same order as you wrote your Methods. One trusted method of writing the results is addressing specific research questions presented in the figures. Within each research question, present the type of data that addresses that research question.

Sample research question asked in a survey:

“What do hospital patients over age 55 think about postoperative care?”

Present this answer as a statement based on the data:

“Hospital patients over the age of 55 were 30% more likely to report negative experiences after postoperative care (M=83; see Fig. 1).”

Elaborate on this finding with secondary information included in the same paragraph:

“The most common negative issues reported were inattention by nurses, lack of proper medicine and a prolonged waiting period for personal issues ((P>12), (W>13), and (D>10); see Fig. 3).”

Caption your figures with the same method, using the data and research question to create phrases that give context to the data:

“Figure 1: Attitudes towards postoperative care in patients over the age of 55.”

Grammar Guidelines for Results

• When referencing figures, use the present tense; when discussing events of the experiment/study, use past tense
• Passive or active voice are generally acceptable—but consistency is most important. (Read articles from target journal).
• Cite the figure or table every time you reference it, just as you would another text.

Dos and Don’ts for Results

• Limit your results to only those that address your research questions; return to the Results section later after you have completed the Introduction and remove less relevant information.
• Indicate the statistical tests used with all relevant parameters. E.g., mean and standard deviation (SD): 44% (±3); median and interpercentile range: 7 years (4.5 to 9.5 years).
• Use mean and standard deviation to report normally distributed data.
• Use median and interpercentile range to report skewed data.
• For numbers, use two significant digits unless more precision is necessary (2.08, not 2.07856444).
• Never use percentages for very small samples. E.g., “one out of two” should not be replaced by 50%.

Step 4: Write the Discussion/Conclusion

This section responds to the question  “What do the results mean?”  This section is easy to write, but difficult to write well. It requires more than a simply analysis—you have to interpret and “sell” your data to the journal and researchers, explaining just how important your findings are. In fact, many manuscripts are rejected because the Discussion section is weak.

The Discussion and Conclusion are often considered to be part of the same section, but the Conclusion is sometimes considered a separate section. At any rate, the Conclusion will be a very short and clear justification of your work or suggestion for future studies.

In the Discussion Section you should:

• Critique your study—be honest about the effectiveness of your design; suggest modifications and improvement.
• Answer this question: “Did your study contribute to knowledge in the field or not?”
• Discuss the impact of this research on related research within the domain

Pre-writing Questions to Answer for the Discussion:

• How do these results relate to the original question or objectives outlined in the Introduction section?
• Do the data support your hypothesis?
• Are your results consistent with what other investigators have reported?
• Discuss weaknesses and discrepancies. If your results were unexpected, try to explain why
• Is there another way to interpret your results?
• What further research would be necessary to answer the questions raised by your results?

Organization of the Discussion Section

The Discussion section is more open than the Results and Methods section, but you should always focus first on what is MOST important and then move to what is less important to your research problem. Divide the analysis of results by paragraph and do not combine unrelated datasets in one paragraph

• The first paragraph/part should summarize the process, the results, and the overall purpose of this study.
• The second paragraph/part should answer questions about the limitations and potential flaws or shortcomings of this study (e.g., the “failure to reveal clear relationships between samples or groups”). Assesses which of the results are most useful in answering the research question.
• The third paragraph should focus on the successes of the study and highlight which method or approach yielded the best results or those most closely hypothesized. You can also compare the results of different methods and assess which was more fruitful and why.
• In subsequent paragraphs, discuss the implications of this research and compare it to the results of other studies. This is the other section (in addition to the Introduction) where you can cite related studies to show how your study compares.

The Conclusion paragraph offers you a chance to briefly show how your work advances the field from the present state of knowledge. It adds a sort of exclamation point at the end of your paper and makes it more memorable as well.

Add a justification for your work here as well as indicate extensions and wider implications, as well as suggest future studies/experiments and point out any work that is currently ongoing. Do not simply repeat the Introduction or abstract here—extend the claims or questions raised in these sections.

Dos and Don’ts for Discussion/Conclusion

• Don’t be TOO broad about the impact of this research—set some limitations.
• Don’t include new terms or ideas in this section—they should be presented in the Introduction.
• Use specific expressions: instead of “higher temperature” write “41ºC”; instead of “at a lower rate” write “0.7% less”; instead of “highly significant” write “p<0.001.”

Step 5: Write the Introduction

The  Introduction section might be the most important section of the body of your paper—it comes first and introduces what you will be doing, telling readers why your work is important.

A good introduction should:

• Establish the context of the work
• State the purpose of the work in the form of a hypothesis, question, or problem investigated
• Give aims and rationale for your approach

Pre-writing questions to answer for the Introduction

• What is the problem to be solved? (background and problem)
• What do we know about this problem? (literature)
• Are there any existing solutions? (literature)
• What are the limitations or gaps in knowledge of existing solutions?
• What do you hope to achieve with this study? (hypothesis/statement of purpose)

Organization of the Introduction

• Background information
• Motivations
• Key primary literature
• Hypothesis/research problem investigated
• Approaches and rationale

Improving Quality of Writing

In order to write an effective research paper, authors need to know what areas of their writing to improve, and this includes avoiding grammar and style errors. Among the top writing errors we see at  Wordvice  are the following:

• Article and Determiner Misuses
• Nominalization and Wordiness
• Usage of Past and Present Tense

Receiving Language Editing Before Submission

After you are finished writing your Results section and have polished the rest of your research paper, be sure to submit your manuscript to an English proofreading service and paper editing service  before delivering it to journal editors for publication. And learn more about the  editing process  to determine which kind of revision your paper needs.

Wordvice Resources

• How to Write a Research Paper Introduction
• Writing the Results Section of a Research Paper
• Which Verb Tenses to Use in a Research Paper
• How to Write an Abstract for a Research Paper
• How to Write a Research Paper Title
• Useful Phrases for Academic Writing
• Common Transition Terms in Academic Papers
• Active and Passive Voice in Research Papers
• 100+ Verbs That Will Make Your Research Writing Amazing
• Tips for Paraphrasing in Research Papers

Related Resources

• Springer Online Research Resources  (Springer)
• ACSESS Digital L ibrary (ASA, CSSA, and SSSA publications for reference)  (ACSESS Digital Library)

Lecture Research Paper Reference

Yoon S-R, Kim SH, Lee H-W, Ha J-H (2017) A novel method to rapidly distinguish the geographical origin of traditional fermented-salted vegetables by mass fingerprinting. PLoS ONE 12(11): e0188217.

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• Published: 08 May 2024

Accurate structure prediction of biomolecular interactions with AlphaFold 3

• Josh Abramson   ORCID: orcid.org/0009-0000-3496-6952 1   na1 ,
• Jonas Adler   ORCID: orcid.org/0000-0001-9928-3407 1   na1 ,
• Jack Dunger 1   na1 ,
• Richard Evans   ORCID: orcid.org/0000-0003-4675-8469 1   na1 ,
• Tim Green   ORCID: orcid.org/0000-0002-3227-1505 1   na1 ,
• Alexander Pritzel   ORCID: orcid.org/0000-0002-4233-9040 1   na1 ,
• Olaf Ronneberger   ORCID: orcid.org/0000-0002-4266-1515 1   na1 ,
• Lindsay Willmore   ORCID: orcid.org/0000-0003-4314-0778 1   na1 ,
• Andrew J. Ballard   ORCID: orcid.org/0000-0003-4956-5304 1 ,
• Joshua Bambrick   ORCID: orcid.org/0009-0003-3908-0722 2 ,
• Sebastian W. Bodenstein 1 ,
• David A. Evans 1 ,
• Chia-Chun Hung   ORCID: orcid.org/0000-0002-5264-9165 2 ,
• Michael O’Neill 1 ,
• David Reiman   ORCID: orcid.org/0000-0002-1605-7197 1 ,
• Kathryn Tunyasuvunakool   ORCID: orcid.org/0000-0002-8594-1074 1 ,
• Zachary Wu   ORCID: orcid.org/0000-0003-2429-9812 1 ,
• Akvilė Žemgulytė 1 ,
• Eirini Arvaniti 3 ,
• Charles Beattie   ORCID: orcid.org/0000-0003-1840-054X 3 ,
• Ottavia Bertolli   ORCID: orcid.org/0000-0001-8578-3216 3 ,
• Alex Bridgland 3 ,
• Alexey Cherepanov   ORCID: orcid.org/0000-0002-5227-0622 4 ,
• Miles Congreve 4 ,
• Alexander I. Cowen-Rivers 3 ,
• Andrew Cowie   ORCID: orcid.org/0000-0002-4491-1434 3 ,
• Michael Figurnov   ORCID: orcid.org/0000-0003-1386-8741 3 ,
• Fabian B. Fuchs 3 ,
• Hannah Gladman 3 ,
• Rishub Jain 3 ,
• Yousuf A. Khan   ORCID: orcid.org/0000-0003-0201-2796 3 ,
• Caroline M. R. Low 4 ,
• Kuba Perlin 3 ,
• Anna Potapenko 3 ,
• Pascal Savy 4 ,
• Sukhdeep Singh 3 ,
• Adrian Stecula   ORCID: orcid.org/0000-0001-6914-6743 4 ,
• Ashok Thillaisundaram 3 ,
• Catherine Tong   ORCID: orcid.org/0000-0001-7570-4801 4 ,
• Sergei Yakneen   ORCID: orcid.org/0000-0001-7827-9839 4 ,
• Ellen D. Zhong   ORCID: orcid.org/0000-0001-6345-1907 3 ,
• Michal Zielinski 3 ,
• Augustin Žídek   ORCID: orcid.org/0000-0002-0748-9684 3 ,
• Victor Bapst 1   na2 ,
• Pushmeet Kohli   ORCID: orcid.org/0000-0002-7466-7997 1   na2 ,
• Max Jaderberg   ORCID: orcid.org/0000-0002-9033-2695 2   na2 ,
• Demis Hassabis   ORCID: orcid.org/0000-0003-2812-9917 1 , 2   na2 &
• John M. Jumper   ORCID: orcid.org/0000-0001-6169-6580 1   na2  

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We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.

• Drug discovery
• Machine learning
• Protein structure predictions
• Structural biology

The introduction of AlphaFold 2 1 has spurred a revolution in modelling the structure of proteins and their interactions, enabling a huge range of applications in protein modelling and design 2–6 . In this paper, we describe our AlphaFold 3 model with a substantially updated diffusion-based architecture, which is capable of joint structure prediction of complexes including proteins, nucleic acids, small molecules, ions, and modified residues. The new AlphaFold model demonstrates significantly improved accuracy over many previous specialised tools: far greater accuracy on protein-ligand interactions than state of the art docking tools, much higher accuracy on protein-nucleic acid interactions than nucleic-acid-specific predictors, and significantly higher antibody-antigen prediction accuracy than AlphaFold-Multimer v2.3 7,8 . Together these results show that high accuracy modelling across biomolecular space is possible within a single unified deep learning framework.

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Author information.

These authors contributed equally: Josh Abramson, Jonas Adler, Jack Dunger, Richard Evans, Tim Green, Alexander Pritzel, Olaf Ronneberger, Lindsay Willmore

These authors jointly supervised this work: Victor Bapst, Pushmeet Kohli, Max Jaderberg, Demis Hassabis, John M. Jumper

Authors and Affiliations

Core Contributor, Google DeepMind, London, UK

Josh Abramson, Jonas Adler, Jack Dunger, Richard Evans, Tim Green, Alexander Pritzel, Olaf Ronneberger, Lindsay Willmore, Andrew J. Ballard, Sebastian W. Bodenstein, David A. Evans, Michael O’Neill, David Reiman, Kathryn Tunyasuvunakool, Zachary Wu, Akvilė Žemgulytė, Victor Bapst, Pushmeet Kohli, Demis Hassabis & John M. Jumper

Core Contributor, Isomorphic Labs, London, UK

Joshua Bambrick, Chia-Chun Hung, Max Jaderberg & Demis Hassabis

Google DeepMind, London, UK

Eirini Arvaniti, Charles Beattie, Ottavia Bertolli, Alex Bridgland, Alexander I. Cowen-Rivers, Andrew Cowie, Michael Figurnov, Fabian B. Fuchs, Hannah Gladman, Rishub Jain, Yousuf A. Khan, Kuba Perlin, Anna Potapenko, Sukhdeep Singh, Ashok Thillaisundaram, Ellen D. Zhong, Michal Zielinski & Augustin Žídek

Isomorphic Labs, London, UK

Alexey Cherepanov, Miles Congreve, Caroline M. R. Low, Pascal Savy, Adrian Stecula, Catherine Tong & Sergei Yakneen

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Corresponding authors

Correspondence to Max Jaderberg , Demis Hassabis or John M. Jumper .

Supplementary information

Supplementary information.

This Supplementary Information file contains the following 9 sections: (1) Notation; (2) Data pipeline; (3) Model architecture; (4) Auxiliary heads; (5) Training and inference; (6) Evaluation; (7) Differences to AlphaFold2 and AlphaFold-Multimer; (8) Supplemental Results; and (9) Appendix: CCD Code and PDB ID tables.

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Abramson, J., Adler, J., Dunger, J. et al. Accurate structure prediction of biomolecular interactions with AlphaFold 3. Nature (2024). https://doi.org/10.1038/s41586-024-07487-w

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Published : 08 May 2024

DOI : https://doi.org/10.1038/s41586-024-07487-w

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Cultural Relativity and Acceptance of Embryonic Stem Cell Research

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There is a debate about the ethical implications of using human embryos in stem cell research, which can be influenced by cultural, moral, and social values. This paper argues for an adaptable framework to accommodate diverse cultural and religious perspectives. By using an adaptive ethics model, research protections can reflect various populations and foster growth in stem cell research possibilities.

INTRODUCTION

Stem cell research combines biology, medicine, and technology, promising to alter health care and the understanding of human development. Yet, ethical contention exists because of individuals’ perceptions of using human embryos based on their various cultural, moral, and social values. While these disagreements concerning policy, use, and general acceptance have prompted the development of an international ethics policy, such a uniform approach can overlook the nuanced ethical landscapes between cultures. With diverse viewpoints in public health, a single global policy, especially one reflecting Western ethics or the ethics prevalent in high-income countries, is impractical. This paper argues for a culturally sensitive, adaptable framework for the use of embryonic stem cells. Stem cell policy should accommodate varying ethical viewpoints and promote an effective global dialogue. With an extension of an ethics model that can adapt to various cultures, we recommend localized guidelines that reflect the moral views of the people those guidelines serve.

Stem cells, characterized by their unique ability to differentiate into various cell types, enable the repair or replacement of damaged tissues. Two primary types of stem cells are somatic stem cells (adult stem cells) and embryonic stem cells. Adult stem cells exist in developed tissues and maintain the body’s repair processes. [1] Embryonic stem cells (ESC) are remarkably pluripotent or versatile, making them valuable in research. [2] However, the use of ESCs has sparked ethics debates. Considering the potential of embryonic stem cells, research guidelines are essential. The International Society for Stem Cell Research (ISSCR) provides international stem cell research guidelines. They call for “public conversations touching on the scientific significance as well as the societal and ethical issues raised by ESC research.” [3] The ISSCR also publishes updates about culturing human embryos 14 days post fertilization, suggesting local policies and regulations should continue to evolve as ESC research develops. [4]  Like the ISSCR, which calls for local law and policy to adapt to developing stem cell research given cultural acceptance, this paper highlights the importance of local social factors such as religion and culture.

I.     Global Cultural Perspective of Embryonic Stem Cells

Views on ESCs vary throughout the world. Some countries readily embrace stem cell research and therapies, while others have stricter regulations due to ethical concerns surrounding embryonic stem cells and when an embryo becomes entitled to moral consideration. The philosophical issue of when the “someone” begins to be a human after fertilization, in the morally relevant sense, [5] impacts when an embryo becomes not just worthy of protection but morally entitled to it. The process of creating embryonic stem cell lines involves the destruction of the embryos for research. [6] Consequently, global engagement in ESC research depends on social-cultural acceptability.

a.     US and Rights-Based Cultures

In the United States, attitudes toward stem cell therapies are diverse. The ethics and social approaches, which value individualism, [7] trigger debates regarding the destruction of human embryos, creating a complex regulatory environment. For example, the 1996 Dickey-Wicker Amendment prohibited federal funding for the creation of embryos for research and the destruction of embryos for “more than allowed for research on fetuses in utero.” [8] Following suit, in 2001, the Bush Administration heavily restricted stem cell lines for research. However, the Stem Cell Research Enhancement Act of 2005 was proposed to help develop ESC research but was ultimately vetoed. [9] Under the Obama administration, in 2009, an executive order lifted restrictions allowing for more development in this field. [10] The flux of research capacity and funding parallels the different cultural perceptions of human dignity of the embryo and how it is socially presented within the country’s research culture. [11]

b.     Ubuntu and Collective Cultures

African bioethics differs from Western individualism because of the different traditions and values. African traditions, as described by individuals from South Africa and supported by some studies in other African countries, including Ghana and Kenya, follow the African moral philosophies of Ubuntu or Botho and Ukama , which “advocates for a form of wholeness that comes through one’s relationship and connectedness with other people in the society,” [12] making autonomy a socially collective concept. In this context, for the community to act autonomously, individuals would come together to decide what is best for the collective. Thus, stem cell research would require examining the value of the research to society as a whole and the use of the embryos as a collective societal resource. If society views the source as part of the collective whole, and opposes using stem cells, compromising the cultural values to pursue research may cause social detachment and stunt research growth. [13] Based on local culture and moral philosophy, the permissibility of stem cell research depends on how embryo, stem cell, and cell line therapies relate to the community as a whole. Ubuntu is the expression of humanness, with the person’s identity drawn from the “’I am because we are’” value. [14] The decision in a collectivistic culture becomes one born of cultural context, and individual decisions give deference to others in the society.

Consent differs in cultures where thought and moral philosophy are based on a collective paradigm. So, applying Western bioethical concepts is unrealistic. For one, Africa is a diverse continent with many countries with different belief systems, access to health care, and reliance on traditional or Western medicines. Where traditional medicine is the primary treatment, the “’restrictive focus on biomedically-related bioethics’” [is] problematic in African contexts because it neglects bioethical issues raised by traditional systems.” [15] No single approach applies in all areas or contexts. Rather than evaluating the permissibility of ESC research according to Western concepts such as the four principles approach, different ethics approaches should prevail.

Another consideration is the socio-economic standing of countries. In parts of South Africa, researchers have not focused heavily on contributing to the stem cell discourse, either because it is not considered health care or a health science priority or because resources are unavailable. [16] Each country’s priorities differ given different social, political, and economic factors. In South Africa, for instance, areas such as maternal mortality, non-communicable diseases, telemedicine, and the strength of health systems need improvement and require more focus [17] Stem cell research could benefit the population, but it also could divert resources from basic medical care. Researchers in South Africa adhere to the National Health Act and Medicines Control Act in South Africa and international guidelines; however, the Act is not strictly enforced, and there is no clear legislation for research conduct or ethical guidelines. [18]

Some parts of Africa condemn stem cell research. For example, 98.2 percent of the Tunisian population is Muslim. [19] Tunisia does not permit stem cell research because of moral conflict with a Fatwa. Religion heavily saturates the regulation and direction of research. [20] Stem cell use became permissible for reproductive purposes only recently, with tight restrictions preventing cells from being used in any research other than procedures concerning ART/IVF.  Their use is conditioned on consent, and available only to married couples. [21] The community's receptiveness to stem cell research depends on including communitarian African ethics.

c.     Asia

Some Asian countries also have a collective model of ethics and decision making. [22] In China, the ethics model promotes a sincere respect for life or human dignity, [23] based on protective medicine. This model, influenced by Traditional Chinese Medicine (TCM), [24] recognizes Qi as the vital energy delivered via the meridians of the body; it connects illness to body systems, the body’s entire constitution, and the universe for a holistic bond of nature, health, and quality of life. [25] Following a protective ethics model, and traditional customs of wholeness, investment in stem cell research is heavily desired for its applications in regenerative therapies, disease modeling, and protective medicines. In a survey of medical students and healthcare practitioners, 30.8 percent considered stem cell research morally unacceptable while 63.5 percent accepted medical research using human embryonic stem cells. Of these individuals, 89.9 percent supported increased funding for stem cell research. [26] The scientific community might not reflect the overall population. From 1997 to 2019, China spent a total of $576 million (USD) on stem cell research at 8,050 stem cell programs, increased published presence from 0.6 percent to 14.01 percent of total global stem cell publications as of 2014, and made significant strides in cell-based therapies for various medical conditions. [27] However, while China has made substantial investments in stem cell research and achieved notable progress in clinical applications, concerns linger regarding ethical oversight and transparency. [28] For example, the China Biosecurity Law, promoted by the National Health Commission and China Hospital Association, attempted to mitigate risks by introducing an institutional review board (IRB) in the regulatory bodies. 5800 IRBs registered with the Chinese Clinical Trial Registry since 2021. [29] However, issues still need to be addressed in implementing effective IRB review and approval procedures.

The substantial government funding and focus on scientific advancement have sometimes overshadowed considerations of regional cultures, ethnic minorities, and individual perspectives, particularly evident during the one-child policy era. As government policy adapts to promote public stability, such as the change from the one-child to the two-child policy, [30] research ethics should also adapt to ensure respect for the values of its represented peoples.

Japan is also relatively supportive of stem cell research and therapies. Japan has a more transparent regulatory framework, allowing for faster approval of regenerative medicine products, which has led to several advanced clinical trials and therapies. [31] South Korea is also actively engaged in stem cell research and has a history of breakthroughs in cloning and embryonic stem cells. [32] However, the field is controversial, and there are issues of scientific integrity. For example, the Korean FDA fast-tracked products for approval, [33] and in another instance, the oocyte source was unclear and possibly violated ethical standards. [34] Trust is important in research, as it builds collaborative foundations between colleagues, trial participant comfort, open-mindedness for complicated and sensitive discussions, and supports regulatory procedures for stakeholders. There is a need to respect the culture’s interest, engagement, and for research and clinical trials to be transparent and have ethical oversight to promote global research discourse and trust.

d.     Middle East

Countries in the Middle East have varying degrees of acceptance of or restrictions to policies related to using embryonic stem cells due to cultural and religious influences. Saudi Arabia has made significant contributions to stem cell research, and conducts research based on international guidelines for ethical conduct and under strict adherence to guidelines in accordance with Islamic principles. Specifically, the Saudi government and people require ESC research to adhere to Sharia law. In addition to umbilical and placental stem cells, [35] Saudi Arabia permits the use of embryonic stem cells as long as they come from miscarriages, therapeutic abortions permissible by Sharia law, or are left over from in vitro fertilization and donated to research. [36] Laws and ethical guidelines for stem cell research allow the development of research institutions such as the King Abdullah International Medical Research Center, which has a cord blood bank and a stem cell registry with nearly 10,000 donors. [37] Such volume and acceptance are due to the ethical ‘permissibility’ of the donor sources, which do not conflict with religious pillars. However, some researchers err on the side of caution, choosing not to use embryos or fetal tissue as they feel it is unethical to do so. [38]

Jordan has a positive research ethics culture. [39] However, there is a significant issue of lack of trust in researchers, with 45.23 percent (38.66 percent agreeing and 6.57 percent strongly agreeing) of Jordanians holding a low level of trust in researchers, compared to 81.34 percent of Jordanians agreeing that they feel safe to participate in a research trial. [40] Safety testifies to the feeling of confidence that adequate measures are in place to protect participants from harm, whereas trust in researchers could represent the confidence in researchers to act in the participants’ best interests, adhere to ethical guidelines, provide accurate information, and respect participants’ rights and dignity. One method to improve trust would be to address communication issues relevant to ESC. Legislation surrounding stem cell research has adopted specific language, especially concerning clarification “between ‘stem cells’ and ‘embryonic stem cells’” in translation. [41] Furthermore, legislation “mandates the creation of a national committee… laying out specific regulations for stem-cell banking in accordance with international standards.” [42] This broad regulation opens the door for future global engagement and maintains transparency. However, these regulations may also constrain the influence of research direction, pace, and accessibility of research outcomes.

e.     Europe

In the European Union (EU), ethics is also principle-based, but the principles of autonomy, dignity, integrity, and vulnerability are interconnected. [43] As such, the opportunity for cohesion and concessions between individuals’ thoughts and ideals allows for a more adaptable ethics model due to the flexible principles that relate to the human experience The EU has put forth a framework in its Convention for the Protection of Human Rights and Dignity of the Human Being allowing member states to take different approaches. Each European state applies these principles to its specific conventions, leading to or reflecting different acceptance levels of stem cell research. [44]

For example, in Germany, Lebenzusammenhang , or the coherence of life, references integrity in the unity of human culture. Namely, the personal sphere “should not be subject to external intervention.” [45]  Stem cell interventions could affect this concept of bodily completeness, leading to heavy restrictions. Under the Grundgesetz, human dignity and the right to life with physical integrity are paramount. [46] The Embryo Protection Act of 1991 made producing cell lines illegal. Cell lines can be imported if approved by the Central Ethics Commission for Stem Cell Research only if they were derived before May 2007. [47] Stem cell research respects the integrity of life for the embryo with heavy specifications and intense oversight. This is vastly different in Finland, where the regulatory bodies find research more permissible in IVF excess, but only up to 14 days after fertilization. [48] Spain’s approach differs still, with a comprehensive regulatory framework. [49] Thus, research regulation can be culture-specific due to variations in applied principles. Diverse cultures call for various approaches to ethical permissibility. [50] Only an adaptive-deliberative model can address the cultural constructions of self and achieve positive, culturally sensitive stem cell research practices. [51]

II.     Religious Perspectives on ESC

Embryonic stem cell sources are the main consideration within religious contexts. While individuals may not regard their own religious texts as authoritative or factual, religion can shape their foundations or perspectives.

The Qur'an states:

“And indeed We created man from a quintessence of clay. Then We placed within him a small quantity of nutfa (sperm to fertilize) in a safe place. Then We have fashioned the nutfa into an ‘alaqa (clinging clot or cell cluster), then We developed the ‘alaqa into mudgha (a lump of flesh), and We made mudgha into bones, and clothed the bones with flesh, then We brought it into being as a new creation. So Blessed is Allah, the Best of Creators.” [52]

Many scholars of Islam estimate the time of soul installment, marked by the angel breathing in the soul to bring the individual into creation, as 120 days from conception. [53] Personhood begins at this point, and the value of life would prohibit research or experimentation that could harm the individual. If the fetus is more than 120 days old, the time ensoulment is interpreted to occur according to Islamic law, abortion is no longer permissible. [54] There are a few opposing opinions about early embryos in Islamic traditions. According to some Islamic theologians, there is no ensoulment of the early embryo, which is the source of stem cells for ESC research. [55]

In Buddhism, the stance on stem cell research is not settled. The main tenets, the prohibition against harming or destroying others (ahimsa) and the pursuit of knowledge (prajña) and compassion (karuna), leave Buddhist scholars and communities divided. [56] Some scholars argue stem cell research is in accordance with the Buddhist tenet of seeking knowledge and ending human suffering. Others feel it violates the principle of not harming others. Finding the balance between these two points relies on the karmic burden of Buddhist morality. In trying to prevent ahimsa towards the embryo, Buddhist scholars suggest that to comply with Buddhist tenets, research cannot be done as the embryo has personhood at the moment of conception and would reincarnate immediately, harming the individual's ability to build their karmic burden. [57] On the other hand, the Bodhisattvas, those considered to be on the path to enlightenment or Nirvana, have given organs and flesh to others to help alleviate grieving and to benefit all. [58] Acceptance varies on applied beliefs and interpretations.

Catholicism does not support embryonic stem cell research, as it entails creation or destruction of human embryos. This destruction conflicts with the belief in the sanctity of life. For example, in the Old Testament, Genesis describes humanity as being created in God’s image and multiplying on the Earth, referencing the sacred rights to human conception and the purpose of development and life. In the Ten Commandments, the tenet that one should not kill has numerous interpretations where killing could mean murder or shedding of the sanctity of life, demonstrating the high value of human personhood. In other books, the theological conception of when life begins is interpreted as in utero, [59] highlighting the inviolability of life and its formation in vivo to make a religious point for accepting such research as relatively limited, if at all. [60] The Vatican has released ethical directives to help apply a theological basis to modern-day conflicts. The Magisterium of the Church states that “unless there is a moral certainty of not causing harm,” experimentation on fetuses, fertilized cells, stem cells, or embryos constitutes a crime. [61] Such procedures would not respect the human person who exists at these stages, according to Catholicism. Damages to the embryo are considered gravely immoral and illicit. [62] Although the Catholic Church officially opposes abortion, surveys demonstrate that many Catholic people hold pro-choice views, whether due to the context of conception, stage of pregnancy, threat to the mother’s life, or for other reasons, demonstrating that practicing members can also accept some but not all tenets. [63]

Some major Jewish denominations, such as the Reform, Conservative, and Reconstructionist movements, are open to supporting ESC use or research as long as it is for saving a life. [64] Within Judaism, the Talmud, or study, gives personhood to the child at birth and emphasizes that life does not begin at conception: [65]

“If she is found pregnant, until the fortieth day it is mere fluid,” [66]

Whereas most religions prioritize the status of human embryos, the Halakah (Jewish religious law) states that to save one life, most other religious laws can be ignored because it is in pursuit of preservation. [67] Stem cell research is accepted due to application of these religious laws.

We recognize that all religions contain subsets and sects. The variety of environmental and cultural differences within religious groups requires further analysis to respect the flexibility of religious thoughts and practices. We make no presumptions that all cultures require notions of autonomy or morality as under the common morality theory , which asserts a set of universal moral norms that all individuals share provides moral reasoning and guides ethical decisions. [68] We only wish to show that the interaction with morality varies between cultures and countries.

III.     A Flexible Ethical Approach

The plurality of different moral approaches described above demonstrates that there can be no universally acceptable uniform law for ESC on a global scale. Instead of developing one standard, flexible ethical applications must be continued. We recommend local guidelines that incorporate important cultural and ethical priorities.

While the Declaration of Helsinki is more relevant to people in clinical trials receiving ESC products, in keeping with the tradition of protections for research subjects, consent of the donor is an ethical requirement for ESC donation in many jurisdictions including the US, Canada, and Europe. [69] The Declaration of Helsinki provides a reference point for regulatory standards and could potentially be used as a universal baseline for obtaining consent prior to gamete or embryo donation.

For instance, in Columbia University’s egg donor program for stem cell research, donors followed standard screening protocols and “underwent counseling sessions that included information as to the purpose of oocyte donation for research, what the oocytes would be used for, the risks and benefits of donation, and process of oocyte stimulation” to ensure transparency for consent. [70] The program helped advance stem cell research and provided clear and safe research methods with paid participants. Though paid participation or covering costs of incidental expenses may not be socially acceptable in every culture or context, [71] and creating embryos for ESC research is illegal in many jurisdictions, Columbia’s program was effective because of the clear and honest communications with donors, IRBs, and related stakeholders.  This example demonstrates that cultural acceptance of scientific research and of the idea that an egg or embryo does not have personhood is likely behind societal acceptance of donating eggs for ESC research. As noted, many countries do not permit the creation of embryos for research.

Proper communication and education regarding the process and purpose of stem cell research may bolster comprehension and garner more acceptance. “Given the sensitive subject material, a complete consent process can support voluntary participation through trust, understanding, and ethical norms from the cultures and morals participants value. This can be hard for researchers entering countries of different socioeconomic stability, with different languages and different societal values. [72]

An adequate moral foundation in medical ethics is derived from the cultural and religious basis that informs knowledge and actions. [73] Understanding local cultural and religious values and their impact on research could help researchers develop humility and promote inclusion.

IV.     Concerns

Some may argue that if researchers all adhere to one ethics standard, protection will be satisfied across all borders, and the global public will trust researchers. However, defining what needs to be protected and how to define such research standards is very specific to the people to which standards are applied. We suggest that applying one uniform guide cannot accurately protect each individual because we all possess our own perceptions and interpretations of social values. [74] Therefore, the issue of not adjusting to the moral pluralism between peoples in applying one standard of ethics can be resolved by building out ethics models that can be adapted to different cultures and religions.

Other concerns include medical tourism, which may promote health inequities. [75] Some countries may develop and approve products derived from ESC research before others, compromising research ethics or drug approval processes. There are also concerns about the sale of unauthorized stem cell treatments, for example, those without FDA approval in the United States. Countries with robust research infrastructures may be tempted to attract medical tourists, and some customers will have false hopes based on aggressive publicity of unproven treatments. [76]

For example, in China, stem cell clinics can market to foreign clients who are not protected under the regulatory regimes. Companies employ a marketing strategy of “ethically friendly” therapies. Specifically, in the case of Beike, China’s leading stem cell tourism company and sprouting network, ethical oversight of administrators or health bureaus at one site has “the unintended consequence of shifting questionable activities to another node in Beike's diffuse network.” [77] In contrast, Jordan is aware of stem cell research’s potential abuse and its own status as a “health-care hub.” Jordan’s expanded regulations include preserving the interests of individuals in clinical trials and banning private companies from ESC research to preserve transparency and the integrity of research practices. [78]

The social priorities of the community are also a concern. The ISSCR explicitly states that guidelines “should be periodically revised to accommodate scientific advances, new challenges, and evolving social priorities.” [79] The adaptable ethics model extends this consideration further by addressing whether research is warranted given the varying degrees of socioeconomic conditions, political stability, and healthcare accessibilities and limitations. An ethical approach would require discussion about resource allocation and appropriate distribution of funds. [80]

While some religions emphasize the sanctity of life from conception, which may lead to public opposition to ESC research, others encourage ESC research due to its potential for healing and alleviating human pain. Many countries have special regulations that balance local views on embryonic personhood, the benefits of research as individual or societal goods, and the protection of human research subjects. To foster understanding and constructive dialogue, global policy frameworks should prioritize the protection of universal human rights, transparency, and informed consent. In addition to these foundational global policies, we recommend tailoring local guidelines to reflect the diverse cultural and religious perspectives of the populations they govern. Ethics models should be adapted to local populations to effectively establish research protections, growth, and possibilities of stem cell research.

For example, in countries with strong beliefs in the moral sanctity of embryos or heavy religious restrictions, an adaptive model can allow for discussion instead of immediate rejection. In countries with limited individual rights and voice in science policy, an adaptive model ensures cultural, moral, and religious views are taken into consideration, thereby building social inclusion. While this ethical consideration by the government may not give a complete voice to every individual, it will help balance policies and maintain the diverse perspectives of those it affects. Embracing an adaptive ethics model of ESC research promotes open-minded dialogue and respect for the importance of human belief and tradition. By actively engaging with cultural and religious values, researchers can better handle disagreements and promote ethical research practices that benefit each society.

This brief exploration of the religious and cultural differences that impact ESC research reveals the nuances of relative ethics and highlights a need for local policymakers to apply a more intense adaptive model.

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[36] Association for the Advancement of Blood and Biotherapies.  https://www.aabb.org/regulatory-and-advocacy/regulatory-affairs/regulatory-for-cellular-therapies/international-competent-authorities/saudi-arabia

[37] Alahmad, G., Aljohani, S., & Najjar, M. F. (2020). Ethical challenges regarding the use of stem cells: Interviews with researchers from Saudi Arabia.  BMC medical ethics ,  21 (1), 35. https://doi.org/10.1186/s12910-020-00482-6

[38] Alahmad, G., Aljohani, S., & Najjar, M. F. (2020). Ethical challenges regarding the use of stem cells: Interviews with researchers from Saudi Arabia. BMC medical ethics , 21(1), 35. https://doi.org/10.1186/s12910-020-00482-6

Culturally, autonomy practices follow a relational autonomy approach based on a paternalistic deontological health care model. The adherence to strict international research policies and religious pillars within the regulatory environment is a great foundation for research ethics. However, there is a need to develop locally targeted ethics approaches for research (as called for in Alahmad, G., Aljohani, S., & Najjar, M. F. (2020). Ethical challenges regarding the use of stem cells: interviews with researchers from Saudi Arabia. BMC medical ethics, 21(1), 35. https://doi.org/10.1186/s12910-020-00482-6), this decision-making approach may help advise a research decision model. For more on the clinical cultural autonomy approaches, see: Alabdullah, Y. Y., Alzaid, E., Alsaad, S., Alamri, T., Alolayan, S. W., Bah, S., & Aljoudi, A. S. (2022). Autonomy and paternalism in Shared decision‐making in a Saudi Arabian tertiary hospital: A cross‐sectional study. Developing World Bioethics , 23 (3), 260–268. https://doi.org/10.1111/dewb.12355 ; Bukhari, A. A. (2017). Universal Principles of Bioethics and Patient Rights in Saudi Arabia (Doctoral dissertation, Duquesne University). https://dsc.duq.edu/etd/124; Ladha, S., Nakshawani, S. A., Alzaidy, A., & Tarab, B. (2023, October 26). Islam and Bioethics: What We All Need to Know . Columbia University School of Professional Studies. https://sps.columbia.edu/events/islam-and-bioethics-what-we-all-need-know

[39] Ababneh, M. A., Al-Azzam, S. I., Alzoubi, K., Rababa’h, A., & Al Demour, S. (2021). Understanding and attitudes of the Jordanian public about clinical research ethics.  Research Ethics ,  17 (2), 228-241.  https://doi.org/10.1177/1747016120966779

[40] Ababneh, M. A., Al-Azzam, S. I., Alzoubi, K., Rababa’h, A., & Al Demour, S. (2021). Understanding and attitudes of the Jordanian public about clinical research ethics.  Research Ethics ,  17 (2), 228-241.  https://doi.org/10.1177/1747016120966779

[41] Dajani, R. (2014). Jordan’s stem-cell law can guide the Middle East.  Nature  510, 189. https://doi.org/10.1038/510189a

[42] Dajani, R. (2014). Jordan’s stem-cell law can guide the Middle East.  Nature  510, 189. https://doi.org/10.1038/510189a

[43] The EU’s definition of autonomy relates to the capacity for creating ideas, moral insight, decisions, and actions without constraint, personal responsibility, and informed consent. However, the EU views autonomy as not completely able to protect individuals and depends on other principles, such as dignity, which “expresses the intrinsic worth and fundamental equality of all human beings.” Rendtorff, J.D., Kemp, P. (2019). Four Ethical Principles in European Bioethics and Biolaw: Autonomy, Dignity, Integrity and Vulnerability. In: Valdés, E., Lecaros, J. (eds) Biolaw and Policy in the Twenty-First Century. International Library of Ethics, Law, and the New Medicine, vol 78. Springer, Cham. https://doi.org/10.1007/978-3-030-05903-3_3

[44] Council of Europe. Convention for the protection of Human Rights and Dignity of the Human Being with regard to the Application of Biology and Medicine: Convention on Human Rights and Biomedicine (ETS No. 164) https://www.coe.int/en/web/conventions/full-list?module=treaty-detail&treatynum=164 (forbidding the creation of embryos for research purposes only, and suggests embryos in vitro have protections.); Also see Drabiak-Syed B. K. (2013). New President, New Human Embryonic Stem Cell Research Policy: Comparative International Perspectives and Embryonic Stem Cell Research Laws in France.  Biotechnology Law Report ,  32 (6), 349–356. https://doi.org/10.1089/blr.2013.9865

[45] Rendtorff, J.D., Kemp, P. (2019). Four Ethical Principles in European Bioethics and Biolaw: Autonomy, Dignity, Integrity and Vulnerability. In: Valdés, E., Lecaros, J. (eds) Biolaw and Policy in the Twenty-First Century. International Library of Ethics, Law, and the New Medicine, vol 78. Springer, Cham. https://doi.org/10.1007/978-3-030-05903-3_3

[46] Tomuschat, C., Currie, D. P., Kommers, D. P., & Kerr, R. (Trans.). (1949, May 23). Basic law for the Federal Republic of Germany. https://www.btg-bestellservice.de/pdf/80201000.pdf

[47] Regulation of Stem Cell Research in Germany . Eurostemcell. (2017, April 26). https://www.eurostemcell.org/regulation-stem-cell-research-germany

[48] Regulation of Stem Cell Research in Finland . Eurostemcell. (2017, April 26). https://www.eurostemcell.org/regulation-stem-cell-research-finland

[49] Regulation of Stem Cell Research in Spain . Eurostemcell. (2017, April 26). https://www.eurostemcell.org/regulation-stem-cell-research-spain

[50] Some sources to consider regarding ethics models or regulatory oversights of other cultures not covered:

Kara MA. Applicability of the principle of respect for autonomy: the perspective of Turkey. J Med Ethics. 2007 Nov;33(11):627-30. doi: 10.1136/jme.2006.017400. PMID: 17971462; PMCID: PMC2598110.

Ugarte, O. N., & Acioly, M. A. (2014). The principle of autonomy in Brazil: one needs to discuss it ...  Revista do Colegio Brasileiro de Cirurgioes ,  41 (5), 374–377. https://doi.org/10.1590/0100-69912014005013

Bharadwaj, A., & Glasner, P. E. (2012). Local cells, global science: The rise of embryonic stem cell research in India . Routledge.

For further research on specific European countries regarding ethical and regulatory framework, we recommend this database: Regulation of Stem Cell Research in Europe . Eurostemcell. (2017, April 26). https://www.eurostemcell.org/regulation-stem-cell-research-europe   

[51] Klitzman, R. (2006). Complications of culture in obtaining informed consent. The American Journal of Bioethics, 6(1), 20–21. https://doi.org/10.1080/15265160500394671 see also: Ekmekci, P. E., & Arda, B. (2017). Interculturalism and Informed Consent: Respecting Cultural Differences without Breaching Human Rights.  Cultura (Iasi, Romania) ,  14 (2), 159–172.; For why trust is important in research, see also: Gray, B., Hilder, J., Macdonald, L., Tester, R., Dowell, A., & Stubbe, M. (2017). Are research ethics guidelines culturally competent?  Research Ethics ,  13 (1), 23-41.  https://doi.org/10.1177/1747016116650235

[52] The Qur'an  (M. Khattab, Trans.). (1965). Al-Mu’minun, 23: 12-14. https://quran.com/23

[53] Lenfest, Y. (2017, December 8). Islam and the beginning of human life . Bill of Health. https://blog.petrieflom.law.harvard.edu/2017/12/08/islam-and-the-beginning-of-human-life/

[54] Aksoy, S. (2005). Making regulations and drawing up legislation in Islamic countries under conditions of uncertainty, with special reference to embryonic stem cell research. Journal of Medical Ethics , 31: 399-403.; see also: Mahmoud, Azza. "Islamic Bioethics: National Regulations and Guidelines of Human Stem Cell Research in the Muslim World." Master's thesis, Chapman University, 2022. https://doi.org/10.36837/ chapman.000386

[55] Rashid, R. (2022). When does Ensoulment occur in the Human Foetus. Journal of the British Islamic Medical Association , 12 (4). ISSN 2634 8071. https://www.jbima.com/wp-content/uploads/2023/01/2-Ethics-3_-Ensoulment_Rafaqat.pdf.

[56] Sivaraman, M. & Noor, S. (2017). Ethics of embryonic stem cell research according to Buddhist, Hindu, Catholic, and Islamic religions: perspective from Malaysia. Asian Biomedicine,8(1) 43-52.  https://doi.org/10.5372/1905-7415.0801.260

[57] Jafari, M., Elahi, F., Ozyurt, S. & Wrigley, T. (2007). 4. Religious Perspectives on Embryonic Stem Cell Research. In K. Monroe, R. Miller & J. Tobis (Ed.),  Fundamentals of the Stem Cell Debate: The Scientific, Religious, Ethical, and Political Issues  (pp. 79-94). Berkeley: University of California Press.  https://escholarship.org/content/qt9rj0k7s3/qt9rj0k7s3_noSplash_f9aca2e02c3777c7fb76ea768ba458f0.pdf https://doi.org/10.1525/9780520940994-005

[58] Lecso, P. A. (1991). The Bodhisattva Ideal and Organ Transplantation.  Journal of Religion and Health ,  30 (1), 35–41. http://www.jstor.org/stable/27510629 ; Bodhisattva, S. (n.d.). The Key of Becoming a Bodhisattva . A Guide to the Bodhisattva Way of Life. http://www.buddhism.org/Sutras/2/BodhisattvaWay.htm

[59] There is no explicit religious reference to when life begins or how to conduct research that interacts with the concept of life. However, these are relevant verses pertaining to how the fetus is viewed. (( King James Bible . (1999). Oxford University Press. (original work published 1769))

Jerimiah 1: 5 “Before I formed thee in the belly I knew thee; and before thou camest forth out of the womb I sanctified thee…”

In prophet Jerimiah’s insight, God set him apart as a person known before childbirth, a theme carried within the Psalm of David.

Psalm 139: 13-14 “…Thou hast covered me in my mother's womb. I will praise thee; for I am fearfully and wonderfully made…”

These verses demonstrate David’s respect for God as an entity that would know of all man’s thoughts and doings even before birth.

[60] It should be noted that abortion is not supported as well.

[61] The Vatican. (1987, February 22). Instruction on Respect for Human Life in Its Origin and on the Dignity of Procreation Replies to Certain Questions of the Day . Congregation For the Doctrine of the Faith. https://www.vatican.va/roman_curia/congregations/cfaith/documents/rc_con_cfaith_doc_19870222_respect-for-human-life_en.html

[62] The Vatican. (2000, August 25). Declaration On the Production and the Scientific and Therapeutic Use of Human Embryonic Stem Cells . Pontifical Academy for Life. https://www.vatican.va/roman_curia/pontifical_academies/acdlife/documents/rc_pa_acdlife_doc_20000824_cellule-staminali_en.html ; Ohara, N. (2003). Ethical Consideration of Experimentation Using Living Human Embryos: The Catholic Church’s Position on Human Embryonic Stem Cell Research and Human Cloning. Department of Obstetrics and Gynecology . Retrieved from https://article.imrpress.com/journal/CEOG/30/2-3/pii/2003018/77-81.pdf.

[63] Smith, G. A. (2022, May 23). Like Americans overall, Catholics vary in their abortion views, with regular mass attenders most opposed . Pew Research Center. https://www.pewresearch.org/short-reads/2022/05/23/like-americans-overall-catholics-vary-in-their-abortion-views-with-regular-mass-attenders-most-opposed/

[64] Rosner, F., & Reichman, E. (2002). Embryonic stem cell research in Jewish law. Journal of halacha and contemporary society , (43), 49–68.; Jafari, M., Elahi, F., Ozyurt, S. & Wrigley, T. (2007). 4. Religious Perspectives on Embryonic Stem Cell Research. In K. Monroe, R. Miller & J. Tobis (Ed.),  Fundamentals of the Stem Cell Debate: The Scientific, Religious, Ethical, and Political Issues  (pp. 79-94). Berkeley: University of California Press.  https://escholarship.org/content/qt9rj0k7s3/qt9rj0k7s3_noSplash_f9aca2e02c3777c7fb76ea768ba458f0.pdf https://doi.org/10.1525/9780520940994-005

[65] Schenker J. G. (2008). The beginning of human life: status of embryo. Perspectives in Halakha (Jewish Religious Law).  Journal of assisted reproduction and genetics ,  25 (6), 271–276. https://doi.org/10.1007/s10815-008-9221-6

[66] Ruttenberg, D. (2020, May 5). The Torah of Abortion Justice (annotated source sheet) . Sefaria. https://www.sefaria.org/sheets/234926.7?lang=bi&with=all&lang2=en

[67] Jafari, M., Elahi, F., Ozyurt, S. & Wrigley, T. (2007). 4. Religious Perspectives on Embryonic Stem Cell Research. In K. Monroe, R. Miller & J. Tobis (Ed.),  Fundamentals of the Stem Cell Debate: The Scientific, Religious, Ethical, and Political Issues  (pp. 79-94). Berkeley: University of California Press.  https://escholarship.org/content/qt9rj0k7s3/qt9rj0k7s3_noSplash_f9aca2e02c3777c7fb76ea768ba458f0.pdf https://doi.org/10.1525/9780520940994-005

[68] Gert, B. (2007). Common morality: Deciding what to do . Oxford Univ. Press.

[69] World Medical Association (2013). World Medical Association Declaration of Helsinki: ethical principles for medical research involving human subjects. JAMA , 310(20), 2191–2194. https://doi.org/10.1001/jama.2013.281053 Declaration of Helsinki – WMA – The World Medical Association .; see also: National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research. (1979).  The Belmont report: Ethical principles and guidelines for the protection of human subjects of research . U.S. Department of Health and Human Services.  https://www.hhs.gov/ohrp/regulations-and-policy/belmont-report/read-the-belmont-report/index.html

[70] Zakarin Safier, L., Gumer, A., Kline, M., Egli, D., & Sauer, M. V. (2018). Compensating human subjects providing oocytes for stem cell research: 9-year experience and outcomes.  Journal of assisted reproduction and genetics ,  35 (7), 1219–1225. https://doi.org/10.1007/s10815-018-1171-z https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6063839/ see also: Riordan, N. H., & Paz Rodríguez, J. (2021). Addressing concerns regarding associated costs, transparency, and integrity of research in recent stem cell trial. Stem Cells Translational Medicine , 10 (12), 1715–1716. https://doi.org/10.1002/sctm.21-0234

[71] Klitzman, R., & Sauer, M. V. (2009). Payment of egg donors in stem cell research in the USA.  Reproductive biomedicine online ,  18 (5), 603–608. https://doi.org/10.1016/s1472-6483(10)60002-8

[72] Krosin, M. T., Klitzman, R., Levin, B., Cheng, J., & Ranney, M. L. (2006). Problems in comprehension of informed consent in rural and peri-urban Mali, West Africa.  Clinical trials (London, England) ,  3 (3), 306–313. https://doi.org/10.1191/1740774506cn150oa

[73] Veatch, Robert M.  Hippocratic, Religious, and Secular Medical Ethics: The Points of Conflict . Georgetown University Press, 2012.

[74] Msoroka, M. S., & Amundsen, D. (2018). One size fits not quite all: Universal research ethics with diversity.  Research Ethics ,  14 (3), 1-17.  https://doi.org/10.1177/1747016117739939

[75] Pirzada, N. (2022). The Expansion of Turkey’s Medical Tourism Industry.  Voices in Bioethics ,  8 . https://doi.org/10.52214/vib.v8i.9894

[76] Stem Cell Tourism: False Hope for Real Money . Harvard Stem Cell Institute (HSCI). (2023). https://hsci.harvard.edu/stem-cell-tourism , See also: Bissassar, M. (2017). Transnational Stem Cell Tourism: An ethical analysis.  Voices in Bioethics ,  3 . https://doi.org/10.7916/vib.v3i.6027

[77] Song, P. (2011) The proliferation of stem cell therapies in post-Mao China: problematizing ethical regulation,  New Genetics and Society , 30:2, 141-153, DOI:  10.1080/14636778.2011.574375

[78] Dajani, R. (2014). Jordan’s stem-cell law can guide the Middle East.  Nature  510, 189. https://doi.org/10.1038/510189a

[79] International Society for Stem Cell Research. (2024). Standards in stem cell research . International Society for Stem Cell Research. https://www.isscr.org/guidelines/5-standards-in-stem-cell-research

[80] Benjamin, R. (2013). People’s science bodies and rights on the Stem Cell Frontier . Stanford University Press.

Mifrah Hayath

SM Candidate Harvard Medical School, MS Biotechnology Johns Hopkins University

Olivia Bowers

MS Bioethics Columbia University (Disclosure: affiliated with Voices in Bioethics)

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Cost-effective topology optimization of masonry structure reinforcements by a linear static analysis-based GA framework

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• Published: 13 May 2024

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• Antonio Pio Sberna 1 ,
• Cristoforo Demartino 2 ,
• Ivo Vanzi 3 ,
• Giuseppe Carlo Marano 1 &
• Fabio Di Trapani   ORCID: orcid.org/0000-0002-7578-0633 1  

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The paper presents a novel optimization framework aimed at the minimization of seismic retrofitting-related costs for existing unreinforced masonry building structures. The framework provides topology optimization of reinforcements (reinforced plasters) to implement in masonry walls for the accomplishment of seismic safety checks under the reference seismic load combinations. Optimization is carried out by a genetic algorithm (GA) developed in MATLAB®, which controls a 3D finite element equivalent frame model of the masonry structure developed in OpenSees. The GA routine iterates the reinforcement configurations employing specific genetic operators. The feasibility of each candidate retrofitting solution is assessed by performing in-plane shear and flexural safety checks of masonry walls. The framework is finally tested with a case study masonry structure supposed to be made of average-quality or poor-quality masonry. Results will show that the proposed framework can effectively provide the minimization of seismic retrofitting costs for existing masonry structures, giving as output the optimal configuration of the reinforcements within the structural layout.

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1 Introduction

In Italy, and the Mediterranean area, a large number of buildings are located in earthquake-prone zones. Unreinforced masonry structures are widespread in these territories. In many cases, these are really old buildings, not conceived to sustain earthquake loads. Seismic events that occurred in the last decades (e.g. L’Aquila in 2009 and Amatrice in 2016, in Italy) demonstrated that seismic risk associated with these structures can be relevant, mainly because of their significant vulnerability. The huge post-earthquake reconstruction costs led Italian, and other governments of countries in seismic-prone areas to allocate funds to prevent earthquake-related disasters by reducing the seismic vulnerability of the existing built heritage. For what concerns unreinforced masonry structures, many effective reinforcements and retrofitting techniques are available as potential technical solutions (e.g. reinforced plasters, grout injections, prestressed ribbons, composite materials, etc.) to supply additional flexural and shear resistance to the walls. On the other hand, formal design criteria addressing the retrofit intervention towards the obtainment of a required performance (e.g. a target safety level or a target structural behaviour) are substantially unavailable. The retrofit design process is mainly based on a trial-and-error approach, which starts from the engineer’s intuition and experience. Such a non-engineered approach has a double drawback. The first is the difficulty of individuating a suitable retrofitting configuration unless making several iterations. In fact, the reinforcement of a wall can involve an increase of the mass or the stiffness or both mass and stiffness, modifying the demand on the structural element (which can even attract more force). Non-negligible recursive design issues can arise in these cases. The second, and related to the previous point, is that there is no control over retrofitting costs. Namely, there is no way to know if a candidate retrofitting configuration is also the one associated with the minimum possible cost. Overestimation of reinforcement is then rather common in these cases, generating additional costs associated with major invasiveness and downtime. Engineered design methodologies addressing a specific target strongly emerge as a need in this field. Over the years, the capability offered by computational intelligence has been more and more employed to solve large and complex structural engineering problems (Quaranta et al. 2020 ; Falcone et al. 2020 ). Many applications addressed sizing, shaping, and topology optimization for the design of new structures (Lagaros et al. 2002 ; Govindaraj and Ramasamy 2005 , 2007 ; Mitropoulou et al. 2011 ; Papavasileiou and Charmpis 2016 ; Babaei and Mollayi 2016 ; Pham and Hong 2022 ; Kanyilmaz et al. 2022 ), founding those evolutionary algorithms, such as genetic algorithms, are suitable to minimize noisy or discrete objective functions.

More recently, evolutionary algorithms started being applied to retrofit design optimization of existing structures. The major interest regarded reinforced concrete structures, for instance, the minimization of the use of carbon fiber reinforced polymers (CFRP) as reinforcements (e.g. Chaves and Cunha 2014 ; Seo et al. 2018 ; Mahdavi et al. 2019 ; Falcone et al. 2019 ). More recently, Papavasileiou et al. ( 2020 ) implemented a novel framework based on a genetic algorithm (GA) for optimizing the implementation costs of three different retrofitting techniques (steel-jacketing, concrete jacketing, and steel braces) for encased steel–concrete composite columns. Similarly, Di Trapani et al. ( 2020 ), proposed a novel framework aimed at minimizing steel jacketing retrofitting costs for RC columns. Afterward, Di Trapani et al. ( 2021 ) extended their optimization framework capability to both ductility-critical and shear-critical RC frame structures. More recently, Minafò and Camarda ( 2022 ) proposed a GA-based optimization procedure for the minimization of the costs of implementation of buckling-restrained braces (BRB) in reinforced concrete frames. Lastly, Di Trapani et al. ( 2022 ) implemented a new genetic algorithm-based framework pinpointing the optimal retrofitting configuration of FRP wrapping of columns and steel bracing in RC structures taking into account both the costs and the expected annual economic losses during the service life. The literature review mentioned so far highlights a growing interest in the application of soft-computing techniques to solve retrofitting design issues. Also, the obtained results demonstrate that this way of approaching the design of seismic retrofit is effective in reducing the costs and invasiveness of the interventions. However, the considered scientific literature reveals an evident lack of experience in the potential application of these soft-computing techniques to the optimization of unreinforced masonry structure seismic retrofit, although the design of reinforcement for masonry structures is not straightforward, as demonstrated by recent studies addressing refined fine element-based topology optimization of fiber reinforcement of masonry walls (Bruggi et al. 2013 , 2014 ; Bruggi and Gabriela 2015 ). Based on these considerations, the current paper proposes a new computational intelligence-based framework supporting the design of seismic reinforcement of existing masonry structures characterized by adequate structural regularity, by minimizing their cost under the constraint of satisfying the safety checks provided by the current technical codes. The optimization algorithm is consistent with the prescriptions and the capacity models provided by the Italian National Technical Code (NTC 2018 ) for the reinforcement of masonry walls, but the framework is robust enough to consider different, or more general, capacity models and safety verification rules. In the paper, the focus is made on the very common reinforced plaster technique. The objective function provided within the optimization algorithm evaluates the intervention costs considering the surface of the walls where reinforced plasters are implemented. The final output of the framework is the optimal retrofitting configuration, namely the topology of walls needing reinforcements associated with the minimum cost and satisfying the safety checks provided by the technical code.

The optimization procedure is carried out by linking the GA optimization routine developed in MATLAB® with an equivalent frame 3D finite element (FE) model analyzed through the OpenSees software platform (McKenna et al. 2000 ). The performance of each tentative solution (namely a candidate configuration for the seismic retrofit), is controlled in terms of in-plane flexural and shear safety checks under the reference seismic design forces. The proposed framework is tested on a 2-storey masonry building supposed to be made of two different typologies of masonry (squared stone unit masonry and coursed tender stone masonry). Results demonstrate that in both cases the application of the proposed GA-based optimization framework can effectively reduce the extent of seismic upgrading interventions enabling cost-saving associated with downtime and invasiveness reduction.

2 Masonry reinforcement with reinforced plasters

2.1 general features of reinforced plasters.

The in-plane reinforcement of masonry walls can be performed according to different techniques (Priestley and Seible 1995 ). Among these, the use of composite materials [e.g., fiber-reinforced polymers (FRP) or fiber-reinforced cementitious matrices (FRCM)] found significant applications for masonries with regular textures. Similarly, the application of prestressed steel ribbons (CAM) has been used especially for masonry buildings belonging to the historical heritage, or in the case of heterogenous masonries. At the same time, the use of reinforced plasters is very common due to their relatively low cost and ease of implementation in comparison with the other techniques. This retrofitting methodology entails the application of a reinforcement net typically made of steel (Fig.  1 a) or Glass Fiber-Reinforced Polymer (GFRP) (e.g. Fig.  1 b) on both faces of the masonry wall, embedded in a thick layer (40–100 mm) of special cement mortar (Fig.  1 c). In the case of GFRP, the net is made up of fiber-glass wires bonded together with an epoxy resin (Gattesco et al. 2015 ; Gattesco and Boem 2015 ). The net shape is created by intertwining the transversal wires with the longitudinal ones. During the implementation, after the demolition of the existing plasters and the outermost layer of mortar joints, the net is placed on the surface of the wall and a layer of shotcrete is implemented. The tiers of reinforced plasters are coupled with underlying the masonry wall by dowels (Fig.  1 c) to prevent debonding and provide some additional confining action.

Application of reinforced plasters to masonry walls: a electro-welded steel net; b GFRP; c scheme of arrangement of the reinforcement

2.2 Capacity models and in-plane safety checks

Differently from FRCM, detailed analytical capacity models for masonry walls reinforced by reinforced plasters are substantially not available in the literature, while Eurocode 8—Part 3 ( 2004b ) provides only general recommendations. The Italian Technical Code (NTC 2018 ) allows the modeling of the effect of reinforced plasters in a simplified way. This provides increasing the original mechanical properties of the masonry (strength and elastic moduli) by an amplification factor (> 1), which in the following will be called α r . The α r coefficient simultaneously applies to the masonry compressive strength ( f m ), shear strength ( τ 0 m ), Young modulus ( E m ), and shear modulus ( G m ), so that:

where the over-signed terms represent the mechanical properties of reinforced walls. The α r coefficients are defined as a function of the original typology of masonry where this intervention is realized. For the reinforced plaster intervention α r coefficients range between 1.2 and 2.5, as shown in Table  1 . The same approach can be applied in the case of wall reinforcements by grout injection or reinforced stitching of mortar joints (Table  1 ), however, in the case of reinforced plasters, the original thickness of the wall ( t ) is increased by the thickness of the reinforced plaster, so that the final thickness \(\overline{t}\) will be:

where t rp is the thickness of the reinforced plaster on each side of the wall.

In-plane safety checks of reinforced masonry (flexure and shear) are simply carried out by using the upgraded thickness of the wall ( \(\overline{t}\) ) and design resistances ( \(\overline{f}_{d}\) and \(\overline{\tau }_{0d}\) ), which are defined as:

where CF and γ M are respectively the confidence factor and the partial safety factor defined according to the technical code. With reference to Fig.  2 , the ultimate flexural resistance ( M u ) is computed as:

where \(\ell\) is the length of the wall, and σ 0  =  N 0 /( \(\ell\) · t ) is the average compressive stress ( N 0 being the current axial force acting on the wall). For an unreinforced wall, the original design strength ( f d ) and thickness ( t ) are used in Eq. ( 4 ).

Reference scheme for the evaluation of in-plane ultimate moment and shear of a reinforced masonry wall

The ultimate shear resistance is evaluated according to the model by Turnšek and Čačovič ( 1971 ) as follows:

where b  =  h / \(\ell\) is the aspect ratio of the wall (1 ≤  b  ≤ 1.5). Again, if the wall is not reinforced, the original shear design strength (τ 0 d ) and thickness ( t ) are used in Eq. ( 5 ). Equations ( 4 – 5 ) are generally conservative, but they can be eventually updated to consider the effect of T-junctions in correspondence of orthogonal walls.

A comparison of the unreinforced and reinforced flexural and shear interaction domains ( N 0  − M u ) and ( N 0  − V u ) by Eqs. ( 4 ) and ( 5 ) is represented in Fig.  3 for a sample masonry wall. It is noteworthy observing that capacity models in Eqs. ( 4 ) and ( 5 ), can be replaced anytime by different, or more refined models without any drawback for the below-discussed optimization framework.

Unreinforced and reinforced flexure and shear interaction diagrams for a sample masonry wall: a N 0  − M u ; b N 0  − V u

3 Optimization framework

3.1 working principles.

The optimization procedure herein proposed is based on the genetic algorithm metaheuristic technique. This class of soft-computing algorithms analyzes the research space through the handling of a set of variables that are gathered in a so-called design vector. Each tentative solution represents a possible retrofitting configuration. The procedure followed in the framework is schematically represented in Fig.  4 . The decision variables, namely the parameters to optimize, are defined at the beginning, once one (or more) strengthening techniques are chosen. This will include the position of the reinforcement and its sizing (if needed). The algorithm starts generating a random initial population of design vectors (tentative solutions) and evaluates the objective function for each individual. For the current application, the objective function will compute the material and manpower cost to implement the reinforcement at the global level, namely the reinforcement of masonry piers. The fittest individuals are then selected, and through the application of the genetic operators, a new generation of tentative solutions is created. Reinforcements for local failure mechanisms are not included in the design optimization process as their design is independent and typically does not need optimization.

Flowchart of the optimization framework

As can be observed from Fig.  4 , the optimization algorithm is the core of the framework, but two fundamental engineering decision phases are left to the designer. The first one is the initial selection of the design variables, which allows the possible definition of a restricted design space (e.g. limiting the optimization to a portion of the building or reducing the number of parameters to be optimized). This operation significantly influences the potential reduction of the computational cost. In the last phase, a restricted number of optimized solutions with similar fitness are compared. The most suitable is then selected by the designer considering the technical feasibility. The main features of the proposed framework are described in detail in the following sections.

3.2 Design vector encoding

The optimization algorithm aims to pinpoint the topology of the walls to be reinforced so that the retrofitting cost is minimized. The topology optimization is performed by using binary variables to encode the presence or not of the reinforcement on each wall. All the decision variables are gathered in the design vector b so defined:

where b ij is a Boolean variable assuming the value 1 if the wall is retrofitted and 0 if not, namely:

where B is the binary set. The subscripts i and j denote the position of the wall in plan and the story, respectively. It is noteworthy observing that walls included in the design vector can have different material properties, and so structures arranged with different typologies of masonry can be also handled by the optimization framework. In order to reduce the dimension of the research space, and so the computational burden required for the analysis, each Boolean variable can also represent a cluster of adjoining walls. Clustering is quite helpful to implement some architectural restraints, to which the seismic intervention must comply.

The choice of the optimization algorithm procedure is felt on genetic algorithms since the approach is particularly efficient in handling a research space defined by Booleans. The implementation or not of the reinforcement intervention as encoded in the design vector is fulfilled by modifying the geometrical and mechanical properties of the walls as provided by Eqs. ( 1 – 3 ).

3.3 Definition of the objective function

The objective function (OF) to be minimized, also called fitness function, evaluates the costs associated with the implementation of the reinforced plaster strengthening intervention. Since the cost is strictly related to the surface of retrofitted walls, the objective function simply appraises the total surface of reinforced plasters that is encoded by the design vector of each individual. To consider the feasibility of each solution (namely if all the safety checks are passed for an individual), the fitness function involves a penalty function, that is used to fictitiously increase the fitness value of unfeasible individuals. The objective function ( OF ( b )) is, therefore defined as:

where C is the cost function and Π the penalty function. As can be noted, the objective function and the cost function depend on the design vector ( b ) representing each individual.

Assuming that the cost per unit surface of reinforced plasters is a constant, the cost function here used will consider only the surface of reinforced plasters, so that:

where A rp , i is the surface of reinforcement applied to the i- th reinforced wall, and n rw is the number of reinforced walls. It is noteworthy observing that, since reinforced plasters are applied at both sides, the surface A rp , i corresponds to twice the area of the reinforced wall panel ( A rw , i ), so that:

The penalty function is instead defined as:

where A wf , j and A ws , k are the areas of the n wf and n ws walls having a strength capacity/demand ratio lower than 1, with respect to flexure and shear safety checks respectively. The i index of the external sum counts the n a seismic analyses performed, namely each different direction and sign considered for the seismic forces. Finally, p is a penalty coefficient fictitiously magnifying the weight of the sums Eq. ( 11 ). The magnification of the penalty function allows the algorithm to be aware of the unfeasible individual’s genomes when generating the new population. Obviously, for a feasible individual one obtains Π = 0.

3.4 Genetic operator subroutines

Genetic algorithms are a population-based class of metaheuristic algorithms inspired by the natural selections of species (Goldberg 1989 ; Holland 1992 ). The main engine of optimal seeking is based upon the concept of survival of the fittest individuals. The algorithm starts generating a random population of tentative solutions (namely candidate retrofitting configuration) and evaluates the fitness associated with them. The pursuit of the research space minima is achieved by selecting the best tentative solutions and creating new individuals starting from their design vectors (namely the genome) through the parent selection, crossover, and mutation genetic operators. The first of these operators selects the parent tentative solutions, the second mixes the genomes of tentative solutions, and the third introduces some randomness in the genome of child individuals to prevent the algorithm stuck into local minima and enhance the genetic diversity of the population. A scheme describing the application of the genetic operators in creating a new individual is illustrated in Fig.  5 . The parent selection operator makes use of tournament selection (Goldberg and Deb 1991 ). Within the current population, k individuals are randomly chosen, and their fitness is evaluated. Among these individuals, the best two (in terms of fitness) are employed as parents. The parameter k is commonly called tournament size. The balancing of this parameter allows controlling of the selective pressure, namely a reduction of k will allow individuals with slightly poorer fitness to generate offspring. On the other hand, an increase of k will permit only the fittest individuals to pass the generation, with a consequent reduction in the diversity of the genetic pool.

Schematic representation of the application of the genetic operators in creating a new individual

A single-point crossover (Kora and Yadlapalli 2017 ) is used to mix the parents’ genome. It selects a random crossover point along the design vector and generates the offspring by taking the first part of the genome from the beginning to the crossover point from the first parent, and the remaining part from the crossover point to the end of the genome from the second parent (Fig.  6 a). In this way, the new individual has inherited a portion of the genome from both parents but keeps intact the characteristics of locality. This means that if a portion of the genome is good in terms of its effect on overall fitness, this can be passed on to the offspring intact.

Working principle of the genetic operators: a single-point crossover; b mutation

Finally, the mutation operator introduces slight changes in the structure of the offspring genome. This prevents the algorithm from being stuck in local minima and promotes the diversity of populations (Squillero and Tonda 2016 ). The mutation is also useful to recover good genetic material that may be lost during selection and crossover operations.

This subroutine operates by setting first a mutation percentage probability ( p m ). Then a random integer percentage number between 0 and 100% is drawn for each decision variable (Fig.  6 b). If the percentage number associated with a decision variable is smaller than the mutation probability, the value of the variable, which is a Boolean variable, is switched. The value of the mutation probability should be chosen properly since low values can reduce the effectiveness of the operator with which the exploitation phase is mainly entrusted. On the other hand, high mutation probability can lead to a radical modification of the genome, making useless the previous selection and crossover operation. Typical values of mutation probability, for this kind of problem, are commonly fixed around 1–5%.

The framework automatically interfaces MATLAB® with OpenSees. For each candidate solution, a set of MATLAB subroutines modify the OpenSees model according to the genome collected in the design vector. The model of each individual is then moved to OpenSees for structural analysis. Results are post-processed in MATLAB for safety checks, fitness evaluation, and application of the genetic operators. In the last stage, the survival selection operator is applied. The latter selects the new population to be analyzed based on a fitness ranking of the individuals, in which only the better ones are used as the new population. The optimization routine is stopped when no further cost reductions are obtained over a certain number of generations. A comprehensive flowchart of the GA framework is illustrated in Fig.  7 .

Flowchart of the genetic algorithm framework

4 Structural modelling and seismic analysis

4.1 reference model for the masonry building structure.

The optimization algorithm is interfaced with an FE solver to perform the structural analysis and the assessment of each tentative solution. For the current study, the optimization algorithm is interconnected with the OpenSees software platform. The masonry structure is defined as an elastic 3D-frame model by employing the Equivalent Frame Method (EFM), which has proven to be reliable for regular masonry building structures (Cattari et al. 2022 ; Camata et al. 2022 ). According to the EFM, the structure is subdivided into masonry panels and spandrels, which are connected through rigid links. The actual deformable length of the walls is evaluated as a function of the opening shape, according to the method by Braga and Dolce ( 1982 ). The remaining unreformable parts are considered as rigid links. In the current study, the elastic portion of masonry walls and spandrels are modelled as Timoshenko beams, using the ElasticTimoshenkoBeam elements implemented in OpenSees. The connection between the orthogonal walls is modelled through rigid trusses using the rigidLink bar element. A rigid diaphragm constraint is applied to the floors. In the FE model, reinforced plasters are modeled according to Eqs. ( 1 – 2 ), that is by modifying the elastic Young’s and shear moduli, and the thickness of the element. The modification of the wall thickness is not only reflected as an increase of the stiffness of the element but also the structural weight and the corresponding masses are updated. A scheme of the reference modeling approach is provided in Fig.  8 . It is noteworthy to observe that the choice of a linear EFM model, although introducing several simplifications and generally being conservative, allows a noticeable reduction of the computational effort, which is a fundamental aspect to the feasibility of the framework.

Reference OpenSees FE model of the masonry structure

4.2 Seismic analysis

The current optimization framework is conceived to be combined with linear seismic analysis (linear equivalent static analysis or response spectrum analysis), to determine the seismic demand in terms of internal forces on the frame elements. The choice of adopting linear seismic analyses differs from some recent studies of the authors (e.g. Di Trapani et al. 2020 , 2021 , 2022 ) where nonlinear static analysis is used. However, in the framework of the algorithm’s efficiency, the adoption of a linear analysis allows a huge reduction of the computational time needed to get the optimal solution. This kind of approach must be interpreted as a fast optimization of the reinforcement. The inelastic performance of the optimal retrofitting solution can anytime be assessed by a nonlinear analysis.

For structures with a regular distribution of masses and stiffness over the height Eurocode 8 ( 2004a ), and Italian Technical Code (NTC 2018 ), allow performing the very simple equivalent static seismic analysis. The latter is briefly recalled as it was used to analyze the case studies presented in the following sections. According to the equivalent static seismic analysis, the total horizontal seismic load is evaluated as:

where S d ( T 1 ) is the design spectral acceleration in correspondence with the vibration period T 1 , W is the total weight of the structure according to the seismic combination of loads, g is the gravitational acceleration, and λ is a corrective factor that is 0.85 if T 1  ≤ 2  T c ( T c being the corner period) and the structure has more than two stories, or 1 otherwise. The fundamental period of vibration of structure ( T 1 ) can be estimated in a simplified way as T 1  =  c 1 ·H 3/4 , where H is the total height of the building in meters and c 1 is 0.05 for masonry structures. The total seismic load ( F h ) is linearly distributed over the height of the building proportionally to the product of the stories’ height and weight. For each candidate solution, the combination of the seismic forces simultaneously acting in the two horizontal orthogonal directions (X and Z) is considered. Specifically, eight analyses are performed by applying 100% of the seismic load in the main direction (X or Z) and 30% in the perpendicular one. Positive and negative verses of actions are considered so that the following combinations are obtained for each analyzed individual:

Seismic forces are applied at the center of mass of each floor. The accidental eccentricity of the center of mass is here neglected for the sake of simplicity.

4.3 Safety checks

Safety checks of masonry walls are carried out for the maximum in-plane flexural capacity ( M u ) and shear capacity ( V u ) of masonry walls. Flexural and shear demands ( M d ) and ( V d ) on the walls are obtained from the seismic analysis of each candidate solution. For each analysis and wall, safety checks will simultaneously verify that:

where M u and V u are evaluated according to Eqs. ( 4 – 5 ). Local out-of-plane mechanisms are not accounted by Eq. ( 14 ), however, they can be added as an additional condition without losing the validity of the framework.

An effective representation of the current flexural and shear safety checks can be performed by defining the dimensionless domains. For the flexural domain, this can be done by normalizing Eqs. ( 4 ) by \(f_{d} \cdot \ell^{2} \cdot t\) , that is:

By defining the normalized axial load as n 0 = σ 0 / f d , from Eq. ( 15 ) one obtains:

Similarly, the dimensionless shear domain can be defined by normalizing Eqs. ( 5 ) by \(b/1.5 \cdot \tau_{0d} \cdot \ell \cdot t\) , so that:

where n v is the ratio between the average normal stress and the diagonal tensile strength (1.5·τ 0d ) of the wall, that is:

In Eqs. ( 15 ) and ( 17 ), the geometrical and mechanical properties of the masonry f d , τ 0 d , and t are respectively changed in \(\overline{f}_{d}\) , \(\overline{\tau }_{0d}\) , and \(\overline{t}\) if the wall is reinforced.

Dimensionless domains are defined by Eqs. ( 16 ) and ( 17 ) by varying n 0 and n v . They allow to define unique interaction domains to graphically represent flexural and shear capacities of all the masonry walls of a structure, regardless of their geometrical dimensions and resistances (Fig.  9 ). The demand points are expressed by the pairs n 0 , m d for flexure and n v , v d for shear, where m d and v d are defined as:

Dimensionless interaction domains and safety checks: a flexure (n 0  − m u ); b shear (n 0  − v u )

Each demand point on the dimensionless diagram represents the condition of a wall with respect to the safety limits for a specific load combination. If one (or more) safety checks are not passed the entire candidate solution is defined as unfeasible and is treated according to the penalty approach defined in Eq. ( 11 ). The use of dimensionless diagrams is particularly suitable to gather in a sole diagram of the safety checks for each wall and load combination.

5 Case study tests

5.1 details of the case study structure.

The proposed optimization framework is tested with the case study of a 3D masonry structure consisting of a C-shape two-storey building having planar dimensions of 27.80 × 12.5 m and with a total height of 8 m (Fig.  10 ). The structure has a symmetry axis along the Z direction. The optimization framework is tested on the building by making two different assumptions for the masonry constituting the wall. In the first case, the structure is supposed to be made of squared stone block masonry (SSM), and in the second case of coursed tender stone masonry (TSM). The average values of the mechanical properties of the two types of masonries are reported in Table  2 . The design values of the compressive strength ( f d ) and shear strength (τ 0 d ) are obtained by Eq. ( 3 ) assuming a knowledge level 2, so that CF = 1.2. The partial safety factor is γ m  = 2.

Geometrical dimensions of the case study structure: a Ground floor; b First floor

For both SSM and TSM the application of reinforced plasters implies an increment coefficient σ R  = 1.5 according to the Italian NTC ( 2018 ) (Table  1 ). The mechanical properties of the reinforced masonries are reported in Table  3 .

The building is supposed to be located in Cosenza (Italy) with a soil type C. The reference nominal life ( V N ) is 100 years. The resulting return period is T R  = 975 years. The fundamental vibration period evaluated for the structure is T 1  = 0.23 s. Given the regularity of the building over the height, the behaviour factor ( q ) is set equal to 3 according to NTC ( 2018 ). The reference elastic and design spectra are depicted in Fig.  11 .

Reference elastic and design spectra

It is assumed that reinforced plasters are implemented with a thickness of t rp  = 50 mm for each side of retrofitted walls. Floors are supposed to be rigid in their plan so that a rigid diaphragm constraint is imposed at the floor nodes. A unit load of q floor 1  = 5.6 kN/m 2 and q roof  = 5.0 kN/m 2 is evaluated for the slab of the first floor and the roof respectively (seismic combination). The resulting total weight of the structure used for the seismic analysis is 9504  kN . In the equivalent frame model, vertical loads are modelled as point loads applied to the top node of each vertical element. Loads from the slabs are transferred to the nodes as a function of the respective tributary areas.

5.2 Preliminary assessment of as-built structures and non-optimized retrofitted structures

Seismic analyses and safety checks of the as-built structures have been carried out according to what was described in the previous section. This preliminary assessment allowed evaluating the walls that were not satisfying flexural and shear safety checks under the reference seismic demand. An overall graphical representation of the safety checks of the structure in the as-built configuration is depicted in Fig.  12 , where different colors are used to denote flexure, shear, and flexure/shear failures of SSM and TSM structures.

Assessment of the structure in the as-built configuration: a Squared stone masonry (SSM); b Tender stone masonry (TSM)

For the SSM structure, 18 out of 78 walls (23%) did not satisfy shear and flexural verifications. For the TSM structure, the walls not passing safety checks were 28, which is 36% of the total. Details about the outcomes of the safety checks of the as-built structures are reported in Table  4 . Assessment of SSM and TSM structure was repeated by applying reinforced plasters to all the walls missing the safety checks. Considering both sides of the walls the surfaces subject to the application of reinforced plasters were 349.7 m 2 and 602 m 2 for the SSM and TSM structure respectively. In both cases this allowed the walls to pass safety checks, although the design of the reinforcement was carried out without any optimization criterion. Assuming an average retrofitting cost of 200 €/m 2 , the total estimated cost for the retrofitting interventions was 69,940 € and 120,480 € for the SSM and TSM structure respectively (Table  5 ). Results of safety checks for every wall and load combination are graphically displayed in Figs. 13 , 14 , where the outcomes of the unreinforced and reinforced structures are overlapped within the dimensionless domains.

Flexural safety checks for the as-built and non-optimized reinforced structures: a Squared stone masonry (SSM); b Tender stone masonry (TSM)

Shear safety checks for the as-built and non-optimized reinforced structures: a Squared stone masonry (SSM); b Tender stone masonry (TSM)

5.3 Results of the application of the optimization framework

The proposed optimization framework has been tested with the case study structures above described. Some preliminary assumptions have been made to reduce the dimension of research space and to avoid unpractical retrofitting configurations. In particular, the adjoining walls were grouped into clusters (Fig.  15 ), so that a cluster of walls became the unit element of the design vector. Besides the reduction of the computational effort, this assumption avoids considering solutions providing scattered reinforcement of the facades. Therefore, the 78 masonry walls were converted into 42 clusters. This allowed reducing the research space to 42 Booleans ( dim ( b ) = 42), instead of 78, which encodes the topology of the reinforcements for the structure. The dimension of the design space is reduced to 2 42  ≈ 4.4 × 10 12 different tentative solutions instead initial dimension of 2 78  ≈ 3.02 × 10 23 .

Subdivision of the walls within the clusters: a ground storey; b first story

The GA routine was run with an initial population ( P ) of 200 tentative random solutions. The algorithm proceeded by generating 200 new children per generation through parent selection, crossover, and mutation operators. A tournament size k  = 3 was used for the parent selection. The mutation probability ( p m ) was set as 5%. The penalty coefficient ( p ) to be used in Eq. ( 11 ), was calibrated with a few trial analyses, which gave better results by setting p  = 5. Stopping criteria have been set to a maximum of 25 generations ( G max ) and a stall of 10 generations ( S max ), representing the maximum number of generations in which the algorithm does not improve the optimal solution. GA parameters set-up is summarized in Table  6 .

The convergence history of the optimization carried out with the proposed GA routine for the SSM and TSM structures is shown in Figs. 16 and 17 in terms of the objective function values (surface of walls subject to retrofit) and the number of retrofitted clusters per individual.

GA optimization convergence history: a Squared stone masonry (SSM); b Tender stone masonry (TSM)

Number of retrofitted clusters during the optimization history: a Squared stone masonry (SSM); b Tender stone masonry (TSM)

As can be observed from Fig.  16 a and b, the optimal solutions were found in the 23rd and 18th generations for the SSM and TSM structure respectively. In both cases, the exploration phase, in which the algorithm investigates roughly the research space seeking the general characteristics of the fittest individuals, was rather steep. It is noteworthy observing that the tender stone masonry case, despite starting from higher fitness values, converged five generations earlier. Further considerations can be made by observing the exploitation phase, where it can be noted that the algorithm maintains a certain diversity over the generations. This allows the algorithms to have the possibility to improve the optimal solution without getting stuck into local minima. The computational time was approximately 1.6 h to complete the optimization routine using a standard computer, meaning approximately 1 second to analyze and assess each candidate solution.

The optimal retrofit configurations found for the two case studies are depicted in Fig.  18 . For the squared stone masonry structure case the total optimized surface of reinforced plasters was 273.6 m 2 . Reinforced clusters were 8, out of 42, with a total of 12 walls out of 78. As regards the tender stone masonry structure case, characterized by poorer strengths the total optimized surface of reinforced plasters was 340 m 2 for 11 clusters, out of 42 and 19 walls out of 78. From Fig.  18 it can be also observed that, for both cases, the optimal retrofitting solutions found through the GA are also satisfactory from an engineering point of view. In fact, the proposed retrofitting configurations do not provide scattered reinforcement of the walls, but these tend to be concentrated in some specific areas. Also, the two-reinforcement layouts approximately reflect the symmetry of the structures along Z direction, confirming that a correct application of the framework can lead to reasonable engineering solutions. The slightly asymmetric layout of the reinforcement is justified by the fact that the optimization algorithm addresses the minimum cost configuration while changing the strength, and particularly the stiffness of some walls. This introduces some plan irregularity and so the optimal solution from the economic point of view may not result in a symmetrical reinforcement layout.

Optimal reinforcement layouts for the case studies: a Squared stone masonry (SSM); b Tender stone masonry (TSM)

A further consideration about the optimization algorithm’s effectiveness can be done by observing the trend of reduction of the average wall surface of reinforced walls. Figure  19 shows the ratio between the moving average of the overall surface of reinforced walls over the generations and the maximum average surface of reinforced walls. It can be observed that for the SSM structure the average area of reinforcement was reduced by 53% with respect to the average of the initial population, while for the TSM structure, the same reduction was 68%. This result denoted the major effectiveness of the algorithm in optimizing the reinforcement of the TSM structure despite the average reinforcement demand for this structure being higher. Safety checks for the structures with the optimized reinforcements are represented with the dimensionless diagrams in Figs. 20 , 21 . The latter are overlapped with those of the non-optimized reinforced structures and the as-built structures.

Trend of the ratio between the moving average of the overall surface of reinforced walls and maximum average surface of reinforced walls during the retrofitting optimization of the two case studies

Flexural safety checks comparisons of the as-built structure and non-optimized and optimized reinforced structures: a Squared stone masonry (SSM); b Tender stone masonry (TSM)

Shear safety checks comparisons of the as-built structure and non-optimized and optimized reinforced structures: a Squared stone masonry (SSM); b Tender stone masonry (TSM)

By comparing the optimal retrofitting solutions of SSM and TSM structures with the non-optimized retrofitted ones (consisting of the reinforcement of all the walls that were not passing safety checks), a significant reduction of the surfaces subject to reinforcement was found. In detail, the area of reinforced plaster for the SSM structure passed from 349.7 m 2 to 273.6 m 2 for the non-optimized and optimized retrofitted cases respectively, with a reduction of − 21.8%. As regards the TSM structures, a major gain was obtained by the application of the proposed optimization framework. In fact, the structure passed from 602.4 m 2 of reinforced plasters needed for the non-optimized case to 340 m 2 for the optimal configuration. In this case, the reduction was − 43.6%. Still assuming a unitary retrofitting cost of 200 €/m 2 the optimal solution found for the SSM structure had a total cost of 54,720 € instead of 69,940 € needed for the reinforcement in the non-optimized case. Considering the TSM structure, the retrofitting cost of the optimal solution was 68,000 € instead of 120,480 € resulting in the non-optimized case. It is noteworthy observing that, in both cases, the proposed framework was able to pinpoint more effective retrofitting solutions, in terms of costs and the surface of reinforced walls (Fig.  22 and Table  7 ). This reduction was much more significant for the tender stone masonry case study structure, which was much more vulnerable to earthquake loads because of the poorer strengths. A general consideration can be drawn from this result. What has been observed is that the application of such a kind of computational intelligence tool is much more helpful in more complex cases, namely where the difference between a non-optimized configuration retrofitting configuration and an optimized one can be relevant. Namely, if safety checks are not passed for a limited percentage number of walls, the adoption of an optimization algorithm could not bring an evident gain. On the contrary, the adoption of genetic algorithms optimization frameworks, like the one illustrated in this paper, could make the difference in terms of intervention cost and invasiveness reduction, and therefore on the quality of the retrofitting design.

6 Conclusions

The paper has shown a novel computational intelligence-based optimization framework for the topology optimization of reinforced plaster reinforcement interventions in existing masonry structures subjected to seismic loads. The optimization routine combined a genetic algorithm developed in MATLAB®, with a FE model developed in OpenSees. The optimization algorithm was tested with a case-study structure, supposing the two sub-cases of average quality masonry (squared stone unit masonry) and poor quality masonry (coursed tender stone masonry). Results were compared with those from a non-optimized design of reinforcements (providing the retrofit of all the walls which were not satisfying safety checks). Based on the obtained results the following major conclusions can be drawn:

The proposed optimization framework can effectively provide topology optimization of reinforcements in existing masonry structures associated with the minimization of seismic retrofitting costs.

The algorithm can properly tackle the optimization problem with the proposed penalty approach despite handling the results of multiple seismic structural analyses and safety checks for each tentative solution.

Both the SSM and TSM case study tests resulted in a significant reduction of the reinforced walls needed to accomplish safety checks. In particular, a major gain was obtained for the structure with poorer masonry, where a reduction of − 43.6% of reinforcements was obtained. This demonstrates the robustness of the algorithm with respect to a potentially different demand for reinforcements as a function of the intrinsic vulnerability of a structure.

Linear elastic analysis allowed reducing the computational effort of the optimization procedure. The designer could possibly test the outcomes with a more refined structural analysis method (e.g., non-linear static analysis).

The computational burden was affordable for the investigated case study, being approximately 1.6 h with a standard computer. However, this largely depends on the dimension of the design vector and on the possible use of parallel computing.

The outcomes of this kind of optimization algorithm should be intended as a preliminary design tool to assist practitioners in individuating cost-effective configurations of the retrofit interventions even for complex structures. Further improvements and generalizations of the proposed approach can include more design variables and local out-of-plane safety checks of masonry piers.

A comparative study between linear and nonlinear static-based optimization of seismic reinforcements would be desirable to strike a balance between computational effort and cost savings.

Data availability

Data are available upon request.

Code availability

Not applicable.

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Open access funding provided by Politecnico di Torino within the CRUI-CARE Agreement. This study was carried out within the «AI-ENVISERS» project—funded by European Union—Next Generation EU within the PRIN 2022 PNRR program (D.D.1409 del 14/09/2022 Ministero dell’Università e della Ricerca).

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Antonio Pio Sberna, Giuseppe Carlo Marano & Fabio Di Trapani

Department of Architecture, Roma Tre University, Via Aldo Manuzio, 68L, Rome, Italy

Cristoforo Demartino

Department of Engineering and Geology, University of Chieti-Pescara “G. D’Annunzio”, Pescara, Italy

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Sberna, A.P., Demartino, C., Vanzi, I. et al. Cost-effective topology optimization of masonry structure reinforcements by a linear static analysis-based GA framework. Bull Earthquake Eng (2024). https://doi.org/10.1007/s10518-024-01900-5

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Received : 27 October 2023

Accepted : 11 March 2024

Published : 13 May 2024

DOI : https://doi.org/10.1007/s10518-024-01900-5

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Novo Nordisk Foundation Center for Basic Metabolic Research

• 'Trojan horse' weight ...

'Trojan horse' weight loss drug more effective than available therapies

A groundbreaking paper in Nature describes a promising new therapy for obesity that leads to greater weight loss in mice than existing medications. The approach smuggles molecules into the brain's appetite centre and affects the brain's neuroplasticity.

“I consider the drugs available on the marked today as the first generation of weight-loss drugs. Now we have developed a new type of weight-loss drug that affects the plasticity of the brain and appears to be highly effective.”

So says Associate Professor and Group Leader Christoffer Clemmensen, from the Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen, who is senior author of the new study, which has been published in the prestigious scientific journal   Nature .

In the study, Christoffer Clemmensen and colleagues demonstrate a new use of the weight loss hormone GLP-1. GLP-1 can be used as a ‘Trojan Horse’ to smuggle a specific molecule into the brain of mice, where it successfully affects the plasticity of the brain and results in weight loss.

“The effect of GLP-1 combined with these molecules is very strong. In some cases, the mice lose twice as much weight as mice treated with GLP-1 only,” Christoffer Clemmensen explains.

This means that future patients can potentially achieve the same effect with a lower dosage. Moreover, the new drug may be an alternative to those who do not respond well to existing weight-loss drugs.

“Our studies in mice show side effects similar to those experienced by patients treated with the weight loss drugs available on the market today, including nausea. But because the drug is so effective, we may be able to lower the dosage and thus mitigate some of the side effects in the future – though we still don’t know how humans respond to the drug,” he says.

Testing of the new weight loss drug is still in the so-called preclinical phase, which is based on studies with cells and on experimental animals. The next step is clinical trials with human participants.

“We already know that GLP-1-based drugs can lead to weight loss. The molecule that we have attached to GLP-1 affects the so-called glutamatergic neurotransmitter system, and in fact, other studies with human participants suggest that this family of compounds has significant weight loss potential. What is interesting here is the effect we get when we combine these two compounds into a single drug,” Christoffer Clemmensen stresses.

The drug must undergo three phases of clinical trials on human participants. According to Christoffer Clemmensen, it can therefore take eight years before the drug could be available on the market

The brain defends excessive body weight

Christoffer Clemmensen and colleagues developed an interest in molecules that are used to treat chronic depression and Alzheimer’s disease.

The molecules block a receptor protein called the NMDA receptor, which play a key role in long-term changes in brain connections and have received scientific attention within fields of learning and memory. Drugs targeting these receptors will strengthen and/or weaken specific nerve connections.

This is a completely new approach for delivering drugs to specific parts of the brain. So, I hope our research can pave the way for a whole new class of drugs for treating conditions like neurodegenerative diseases or psychiatric disorders.” Associate Professor Christoffer Clemmensen

“This family of molecules can have a permanent effect on the brain. Studies have demonstrated that even a relative infrequent treatment can lead to persistent changes to the brain pathologies. We also see molecular signatures of neuroplasticity in our work, but in this case in the context of weight loss,” he explains.

The human body has evolved to protect a certain body weight and fat mass. From an evolutionary perspective, this has probably been to our advantage, as it means that we have been able to survive periods of food scarcity. Today, food scarcity is not a problem in large parts of the world, where an increasing part of the population suffers from obesity.

“Today, more than one billion people worldwide have a BMI of 30 or more. This makes it increasingly relevant to develop drugs to aid this disease, and which can help the organism to sustain a lower weight. This topic is something we invest a lot of energy in researching,” says Christoffer Clemmensen.

A Trojan Horse smuggles small molecule modulators of neuroplasticity into appetite-regulating neurons

We know that drugs based on the intestinal hormone GLP-1 effectively target the part of the brain that is key to weight loss, namely the appetite control centre.

“What is spectacular – on a cellular level – about this new drug is the fact that it combines GLP-1 and molecules that block the NMDA receptor. It exploits GLP-1 as a Trojan Horse to smuggle these small molecules exclusively into the neurons that affect appetite control. Without GLP-1, the molecules that target the NMDA receptor would affect the entire brain and thus be non-specific,” says Postdoc Jonas Petersen from the Clemmensen Group, who is the first author on the study and the chemist who synthesized the molecules.

Non-specific drugs are often associated with severe side effects, which has previously been seen in drugs for treating different neurobiological conditions.

“A lot of brain disorders are difficult to treat, because the drugs need to cross the so-called blood-brain barrier. Whereas large molecules like peptides and proteins generally have difficulties accessing the brain, many small molecules have unlimited access to the entire brain. We have used the GLP-1 peptide’s specific access to the appetite control centre in the brain to deliver one of these otherwise non-specific substances to this region only,” Christoffer Clemmensen says and adds:

“In this study, we have focused on obesity and weight loss, but in fact this is a completely new approach for delivering drugs to specific parts of the brain. So, I hope our research can pave the way for a whole new class of drugs for treating conditions like neurodegenerative diseases or psychiatric disorders.”

Christoffer Clemmensen, along with postdoc Jonas Petersen and a former scientist from the University of Copenhagen (Anders Klein), have co-founded of the biotech company Ousia Pharma, which is a spinout company from the University of Copenhagen. The company is continuing to develop the medical concept presented in this study for the treatment of severe obesity.

You can read the whole paper ” GLP-1-directed NMDA receptor antagonism for obesity treatment ” in Nature.

Associate Professor Christoffer Clemmensen [email protected] +4522916333

Journalist and press consultant Liva Polack [email protected] +4535325464