Scientific writing 3.0: A reader and writer's guide - Jean-Luc Lebrun, Justin Lebrun 2021

The four parts
Abstract: the heart of your paper
Paper structure and purpose

The heart plays an essential role in the human body. Similarly, the essence of an article is its abstract. The heart has four chambers. The abstract is also composed of four easily identifiable parts.

Visuals in Abstracts?

Never say never! I used to think that abstracts had no visuals, but it looks as though I was mistaken. The table of contents of some journals (e.g. Advanced Materials, Journal of the American Chemical Society) now include one key visual alongside an abridged abstract. Is this a preview of the shape of things to come for all journals? I believe it is. A good figure far exceeds plain text in illustrating and explaining a contribution efficiently and concisely. Therefore, take note and prepare yourself. Which visual will be ’the one’ to choose for your abstract?

The abstract dissected here is at the crossroads between surgery and computer science. It comes from a paper on slit arteriotomy. The easiest way to explain arteriotomy is to visualize the surgical connection of two tubes (here, arteries). Normally the surgeon cuts an elliptic hole (with removal of material) in the recipient artery and then stitches the donor artery over the hole. In this case, however, only a slit is cut in the side of the recipient artery before the donor artery is stitched over it. No material is removed.

Does slit arteriotomy work as well as hole arteriotomy? Even if the answer is yes, surgeons are conservative. If an established procedure (the hole arteriotomy) works, why is there a need to replace it with a new one (slit arteriotomy)! Initial statistics that establish the equivalence of both techniques are not enough. What will happen to the slit in ten years when arteries age or when the patient’s blood pressure rises? To find out the safety and efficacy of the new technique over time, the inventor surgeon asked for the help of computer-modeling scientists. The technique was modeled, and a paper¹ was published in the Journal of Biomechanics. The readers of this journal come from diverse horizons: life science, engineering science, and computer science. When they glanced at the table of contents of volume 39 of the journal, they saw the following title:

Nonlinear Finite Element Simulation to Elucidate the Efficacy of Slit Arteriotomy for End-to-side Arterial Anastomosis in Microsurgery²

The title has two parts: contribution and background. If you were to insert a dividing bar | between these two parts, where would you place it? The answer will come later, after you read the abstract. Note that the words in bold are common to both the abstract and the title.

“[Part 0—20 words] The slit arteriotomy for end-to-side arterial Microanastomosis is a technique used to revascularize free flaps in reconstructive surgery. [Part 1—41 words] Does a slit open to a width sufficient for blood supply? How is the slit opening affected by factors such as arterial wall thickness and material stiffness? To answer these questions we propose a non-linear finite element procedure to simulate the operation. [Part 2—10 words] Through modeling the arteries using hyperelastic shell elements, our simulation [Part 3—112 words] reveals that the slit opens to a width even larger than the original diameter of the donor artery, allowing sufficient blood supply. It also identifies two factors that explain the opening of the slit: blood pressure which is predominant in most cases, and the forces applied to the slit by the donor artery. During simulation, when we increase the donor artery thickness and stiffness, it is found that the contribution of blood pressure to the slit opening decreases while that of the forces applied by the donor artery increases. This result indicates that sometimes the forces by the donor artery can play an even more significant role than the blood pressure factor.

[Part 4—28 words] Our simulation elucidates the efficacy of the slit arteriotomy. It improves our understanding of the interplay between blood pressure and donor vessel factors in keeping the slit open. [Total: 211 words].

Where does the bar “|” fall, in other words, where is the separation between the contribution and the context of the contribution?

“Nonlinear Finite Element Simulation to Elucidate the Efficacy of Slit Arteriotomy | for End-to-side Arterial Anastomosis in Microsurgery”

In our sample abstract, if one locates the contribution based on the word count in each part, it seems that part 3, the elucidation of the efficacy, covers the contribution (112 words). Part 2, the non-linear finite element analysis, plays an incidental role (only 10 words), yet it comes right upfront in the title. The title could have been the following:

Elucidating the Efficacy of Slit Arteriotomy | for End-to-side Arterial Anastomosis in Microsurgery using non linear finite element simulation

However, after examining the structure of the paper (headings and subheadings), it appears that the contribution is indeed the nonlinear finite element simulation. The title tallies with the structure, less so with the abstract. One concludes that the abstract is aimed at surgeons who care little about the technical details of the finite element simulation. They may never read the paper, and be content reading the abstract. Had the paper targeted computer scientists, the methodology part would have been longer and the results part shorter.

The four parts

Each of the four parts in the abstract (separated by word count) answers key reader questions.

Part 1: What is the problem? What is the topic, the aim of this paper?

Part 2: How is the problem solved, the aim achieved (methodology)?

Part 3: What are the specific results? How well is the problem solved?

Part 4: So what? How useful is this to Science and to the reader?

You may have noticed that our sample abstract has a Part 0. It is optional, and not recommended, apart from situations such as the one arising in our sample abstract. The writer, anticipating that the meaning of a keyword in the title may be obscure to non-surgeons, provides just-in-time background — in this case, a functional definition of the surgical procedure.

A four-part abstract should be the norm, but many have only three parts: the fourth one (the impact) is missing. Why?

1)It could be that the author reached the maximum number of words too early. Some authors ramble on about the need for a solution in their abstract, but then run out of space describing the benefits of that solution.

2)Did the author (mistakenly) consider that the results speak for themselves? Again, it is worth repeating that the writer must have a reader in mind when writing a paper. Who is likely to benefit from the research? The impact of the paper is what convinces a reader to download your paper. And that reader may not have enough knowledge to determine the impact (outcomes) made possible by the results (outputs).

3)Could it be that the author was unable to assess the impact as a result of the myopia caused by the atomization of research tasks among many researchers?

4)Could it be that the author was unable to mention any impact because the contribution is only a small improvement over a previous result, not enough to claim significant impact?

Whatever the reason, having less than four parts reduces the informative value of the abstract and, therefore, its value to the reader. Since the reader decides whether to read the rest of your article or not based on the abstract, its incompleteness reduces your chances to be read… and cited.