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New technologies to prevent post-operative hernias

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Baptiste PILLET, Mines Saint-Etienne – Institut Mines-Télécom

The abdomen experiences intra-abdominal pressure, which varies according to the volume of organs, respiration, muscle activation and any physiological activity. As a consequence, the abdomen must resist forces exerted by this pressure, which can at times be high when coughing or vomiting, or during pregnancy. Certain illnesses such as obesity, paired with high intra-abdominal pressure, can lead to a hernia forming.

A hernia is when an organ, such as the small intestine, pushes through a natural opening, leaving its original cavity. It is a pathological protrusion, most often caused by weakness in the tissue that fails to resist the pressure from the organ. Factors such as obesity or repeatedly carrying heavy loads can increase this internal pressure, thereby making it more likely for the balance between tissue and organs to be disrupted.

It is a common condition, accounting for over 100,000 operations in France in 2020. If a hernia worsens, it can lead to bowel obstruction, which is why surgery is often preferred as a prophylaxis (preventively). Surgery involves reducing the protrusion and returning the intestine to its cavity.

Inguinal hernias are when the hernia is located just above the groin crease, whereas femoral hernias are located below the groin crease. Umbilical hernias occur near the navel, and lastly, epigastric hernias are located between the abdominal muscles, above the navel. In general, femoral hernias are more common in women and more complicated than inguinal hernias, which are more common in men. Umbilical hernias often occur after the umbilical orifice does not close correctly, and are therefore more common in infants.

Reducing hernias after abdominal surgery

After abdominal surgery, the resistance and mechanical behavior of the abdominal wall may be disrupted, which can lead to an incisional hernia (also known as an ‘eventration’). During a laparotomy (vertical incision of the abdomen), the linea alba (connective tissue between the rectus abdominis) presents areas of weakness after scarring over, which may later reopen. Such incisions of the abdomen may be necessary in around a hundred operations (organ transplant, cesarean section, etc.) and yet they lead to up to 11% of incisional hernias.

Although at present there is no means to detect and prevent abdominal hernias (natural or incisional), efforts have been made to reduce the rate of complications. From now on, in the majority of abdominal reconstructions (during a laparotomy or hernia repair), mesh is inserted between the various layers of muscle to strengthen the abdominal wall and therefore reduce the risk of recurrent hernia or eventration.

When such mesh is not used, the rate of recurrence is around 50%. Approximately 400,000 abdomen repairs using mesh take place each year in Europe, representing a cost of around €3.2 billion. This makes it one of the most common general surgeries, and yet, the rate of recurrence is still far too high (between 14 and 44%). Even 1% fewer recurrences would save €32 million a year.

The reinforcement mesh used has the purpose of strengthening areas of weakness during scarring and filling orifices to rebuild the abdominal wall. The surrounding biological tissue will then colonize the implant to return to a state close to the original. At present, the mesh is manufactured with resorbable or non-resorbable synthetic fibers, sometimes with derivatives from organic tissue (dermis or submucosa from human, porcine or bovine small intestine). It is characterized by the size of the pores, fiber diameter and thickness, etc. as well as mechanical characteristics, such as its resistance to stretching, bending, rupture, etc.

Better understanding recurrence

Mechanical tests and postoperative monitoring with imaging are taking place to understand the rate of recurrence, which remains too high. Often the mesh does not present the same mechanical behavior and therefore does not reproduce and adapt to that of the abdominal wall in the best way (mesh too rigid, for example). While the mechanical behavior of the mesh and abdominal wall has been relatively well studied in the literature, there remains a lack of understanding around the mesh’s integration in the abdomen environment. The initially implanted mesh will evolve in its behavior and effect on the abdominal wall over time as it integrates into the surrounding tissue. Moreover, it has been observed that the mesh has a tendency to contract or even deteriorate over time.

Digital models representing the abdomen and its repair are starting to be developed. Similarly, while more and more innovative research is appearing, there remains a lack of understanding around the high rate of recurrence, due to a shortage of data on these digital models. Specifically, there is no simulation that makes it possible to study and faithfully predict how the abdominal wall reopens, even when the mesh has been implanted.

With the aim of filling this knowledge gap, an animal study is underway to observe the role of mesh in reconstructing the abdominal wall following an incisional hernia.

The mechanical characteristics will be studied at multiple postoperative intervals through mechanical tests, and the integration of the mesh will be closely monitored thanks to medical imaging. At the same time, a digital model will be developed to represent the abdomen and its components (various layers of muscle, connective tissues, etc.) as accurately as possible.

The mechanical data will be then implemented into the model to analyze the mesh’s integration into its environment, as well as its effects over time. According to the placement of the textile, how it is attached and the physiological activity, it will be able to predict whether or not a reopening will occur, where it will arise and whether it will spread. This digital model could allow for better understanding of the abdominal wall mesh repair process and thereby improve implants, surgical techniques and consequently, treatment outcomes.

Baptiste Pillet, Lecturer-Researcher and Biomechanics PhD student, Mines Saint-Etienne – Institut Mines-Télécom

This article was republished from The Conversation under the Creative Commons license. Read the original article here (in French).

web browsing

How our Web browsing has changed in 30 years

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Victor Charpenay, Mines Saint-Étienne – Institut Mines-Télécom

On August 5, 1991, a few months before I was born, Tim Berners-Lee unveiled his invention, called the “World Wide Web”, to the public and encouraged anyone who wanted to discover it to download the world’s very first prototype Web “browser”. This means that the Web as a public entity is now thirty years old.

Tim Berners-Lee extolled the simplicity with which the World Wide Web could be used to access any information using a single program: his browser. Thanks to hypertext links (now abbreviated to hyperlinks), navigation from one page to another was just a click away.

However, the principle, which was still a research topic at that time, seems to have been undermined over time. Thirty years later, the nature of our web browsing has changed: we are visiting fewer websites but spending more time on each individual site.

Hypertext in the past: exploration

One of the first scientific studies of our browsing behavior was conducted in 1998 and made a strong assumption: that hypertext browsing was mainly used to search for information on websites – in short, to explore the tree structure of websites by clicking. Search engines remained relatively inefficient, and Google Inc. had just been registered as a company. As recently as 2006 (according to another study published during the following year), it was found that search engines were only used to launch one in six browsing sessions, each of which then required an average of a dozen clicks.

L’attribut alt de cette image est vide, son nom de fichier est file-20210906-17-xeytzq.jpg.
Jade boat, China. Metropolitan Museum of Art, archive.org

Today, like most Internet users, your first instinct will doubtless be to “Google” what you are looking for, bypassing the (sometimes tedious) click-by-click search process. The first result of your search will often be the right one. Sometimes, Google will even display the information you are looking for directly on the results page, which means that there will be no more clicks and therefore no more need for hypertext browsing.

To measure this decline of hypertext from 1998 to today, I conducted my own (modest) analysis of browsing behavior, based on the browsing history of eight people over a two-month period (April-May 2021), who sent me their histories voluntarily (no code was hidden in their web pages, in contrast to the practices of other browsing analysis algorithms), and the names of the visited web sites were anonymized (www.facebook.com became *.com). Summarizing the recurrent patterns that emerged from these browsing histories shows not only the importance of search engines, but also the concentration of our browsing on a small number of sites.

Hypertext today: the cruise analogy

Not everyone uses the Web with the same intensity. Some of the histories analyzed came from people who spend the vast majority of their time in front of the screen (me, for example). These histories contain between 200 and 400 clicks per day, or one every 2-3 minutes for a 12-hour day. In comparison, people who use their browser for personal use only perform an average of 35 clicks per day. Based on a daily average of 2.5 hours of browsing, an Internet user clicks once every 4 minutes.

What is the breakdown of these clicks during a browsing session? One statistic seems to illustrate the persistence of hypertext in our habits: three quarters of the websites we visit are accessed by a single click on a hyperlink. More precisely, on average, only 23% of websites are “source” sites, originating from the home page, a bookmark or a browser suggestion.

However, the dynamics change when we analyze the number of page views per website. Indeed, most of the pages visited come from the same sites. On average, 83% of clicks take place within the same site. This figure remains relatively stable over the eight histories analyzed: the minimum is 73%, the maximum 89%. We typically jump from one Facebook page to another, or from one YouTube video to another.

There is therefore a dichotomy between “main” sites, on which we linger, and “secondary” sites, which we consult occasionally. There are very few main sites: ten at the most, which is barely 2% of all the websites a person visits. Most people in the analysis have only two main sites (perhaps Google and YouTube, according to the statistics of the most visited websites in France).

On this basis, we can paint a portrait of a typical hypertext browsing session, thirty years after the widespread adoption of this principle. A browsing session typically begins with a search engine, from which a multitude of websites can be accessed. We visit most of these sites once before leaving our search engine. We always visit the handful of main sites in our browsing session via our search engine, but once on a site, we carry out numerous activities on it before ending the session.

The diagram below summarizes the portrait I have just painted. The websites that initiate a browsing session are in yellow, the others in blue. By analogy with the exploratory browsing of the 90s, today’s browsing is more like a slow cruise on a select few platforms, most likely social platforms like YouTube and Facebook.

L’attribut alt de cette image est vide, son nom de fichier est file-20210831-23-1jlvak1.png.
A simplified graph of browsing behavior; the nodes of the graph represent a website (yellow for a site initiating a browsing session, blue for other sites) and the lines represent one or more clicks from one site toward another (the thickness of the lines is proportional to the number of clicks). Victor Charpenay, provided by the author.

The phenomenon that restricts our browsing to a handful of websites is not unique to the web. This is one of the many examples of Pareto’s law, which originally stated that the majority of the wealth produced was owned by a minority of individuals. This statistical law crops up in many socio-economic case studies.

However, what is interesting here is that this concentration phenomenon is intensifying. The 1998 study gave an average of 3 to 8 pages visited per website. The 2006 survey reported 3.4 page visits per site. The average I obtained in 2021 was 11 page visits per site.

Equip your navigator with a “porthole”

The principle of hypertext browsing is nowadays widely abused by the big Web platforms. The majority of hyperlinks between websites – as opposed to self-referencing links (those directed by websites back to themselves, shown in blue on the diagram above) – are no longer used by humans for browsing but by machines for automatically installing fragments of spyware code on our browsers.

There is a small community of researchers who still see the value of hypermedia on the web, especially when users are no longer humans, but bots or “autonomous agents” (which are programmed to explore the Web rather than remain on a single website). Other initiatives, like Solid – Tim Berners-Lee’s new project – are trying to find ways to give Internet users (humans or bots) more control over their browsing, as in the past.

As an individual, you can monitor your own web browsing in order to identify habits (and possibly change them). The Web Navigation Window browser extension, available online for Chrome and Firefox, can be used for this purpose. If you wish, you could also contribute to my analysis by submitting your own history (with anonymized site names) via this extension. To do so, just follow the corresponding hyperlink.

Victor Charpenay, Lecturer and researcher at the Laboratory of Informatics, Modeling and Optimization of Systems (LIMOS), Mines Saint-Étienne – Institut Mines-Télécom

This article has been republished from The Conversation under a Creative Commons license. Read the original article (in French).

gestion des déchets, waste management

Waste management: decentralizing for better management

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Reducing the environmental impact of waste and encouraging its reuse calls for a new approach to its management. This requires the modeling of circuits on a territorial scale, and the improvement of collaboration between public and private actors.

Territorial waste management is one of the fundamental aspects of the circular economy. Audrey Tanguy,1 a researcher at Mines Saint-Étienne, is devoting some of her research to this subject by focusing on the development of approaches to enable the optimal management of waste according to its type and the characteristics of different territories. “The principle is to characterize renewable and local resources in order to define how they can be processed directly on the territory,” explains Audrey Tanguy. Organic waste, for example, should be processed using the shortest possible circuits because it degrades quickly. Current approaches tend to centralize as much waste as possible with a view to its processing, while circular approaches tend towards more local, decentralized circuits. Decentralization can be supported by low-tech technologies, which optimize local recycling or composting in the case of organic waste, especially in the urban environment.

The research associated with waste processing therefore aims to find ways to relocate these flows. Modeling tools can help to spatialize these flows and then provide guidance for decision-makers on how to accommodate local channels. “Traditional waste-processing impact assessment tools assess centralized industrial systems, so we need to regionalize them,” explains Audrey Tanguy. These tools must take the territorial distribution of resources into account, regardless of whether they are reusable. In other words, they must determine which are the main flows that can be engaged in order to recover and transform materials. “It is therefore a question of using the appropriate method to prioritize the collection of materials, and to this end, an inventory of the emission and consumption flows needs to be drawn up within the territory,” states the researcher.

Implementation of strategies in the territories

In order to implement circular economy strategies on a territorial scale, the collaboration of different types of local actors is essential. Beyond the tools required, researchers and the organizations in place can also play an important role by helping the decision-makers to carry out more in-depth investigations of the various activities present in the chosen territory. This enables the definition of collaborative strategies in which certain central stakeholders galvanize the actions of the other actors. For example, business associations or local public-private partnership associations promote policies that support industrial strategies. A good illustration is the involvement of the Macéo association, in partnership with Mines Saint-Étienne, in the implementation of strategies for the recycling and recovery of plastic waste in the Massif Central region. It acts as a central player in this territory and coordinates the various actions by implementing collaborative projects between companies and communities.

The tools also provide access to quantitative data about the value of potential exchanges between companies and enable the comparison of different scenarios based on exchanges. This can be applied to aspects of the pooling of transport services, suppliers or infrastructure. Even if these strategies do not concern core industrial production activities, they lay the foundations for future strategies on a broader scale by establishing trust between different actors.

Reindustrialisation of territories

“We assume that in order to reduce our impacts, one of the strategies to be implemented is the reindustrialization of territories to promote shorter circuits,” explains Natacha Gondran,1 a researcher in environmental assessment at Mines Saint-Étienne. “This may involve trade-offs, such as sometimes accepting a degree of local degradation of the measured impacts in exchange for a greater reduction in the overall impact,” the researcher continues.

Reindustrializing territories is therefore likely to favor the implementation of circular dynamics. Collaboration between different actors at the local level could in this way provide appropriate responses to global issues concerning the pressure on resources and emissions linked to human activities. “This is one of the strategies to be put in place for the future, but it is also important to rethink our relationship with consumption in order to reduce it and embrace a more moderate approach,” concludes Natacha Gondran.

1 Audrey Tanguy and Natacha Gondran carry out their research in the framework of the Environment, City and Society Laboratory, a joint CNRS research unit composed of 7 members including Mines Saint-Étienne.

Antonin Counillon

This article is part of a 2-part mini-series on the circular economy.
Read the previous article:

Economics – dive in, there is so much to discover!
RAMP UP Seed

Supporting companies in the midst of crisis

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The RAMP-UP Seed project is one of 9 new projects to have been selected by the German-French Academy for the Industry of the Future as part of the “Resilience and Sustainability for the Industry of the Future” call for projects. It focuses on helping companies adapt their production capacities to respond to crisis situations. The project relies on two main areas of expertise to address this issue: ramp-up management and artificial intelligence (AI). Khaled Medini and Olivier Boissier, researchers at Mines Saint-Étienne,[1] a partner of the project, present the issues.

Can you describe the context for the RAMP-UP Seed project?

Khaled Medini The RAMP-UP Seed project is one of 9 new projects to have been selected by the German-French Academy for the Industry of the Future (GFA) for the call for projects on the sustainability and resiliency of companies in the industry of the future. This project is jointly conducted by Mines Saint-Étienne and TUM (Technische Universität München), and is a continuation of work carried out on diversity management, ramp-up management, and multi-agent systems at Institut Fayol related to the industry of the future.

What is the project’s goal?

KM The health crisis has highlighted the limitations of current industrial models when it comes to providing a quick response to market demands in terms of quality and quantity, and production constraints related to crisis situations. Ramp-up and ramp-down management is a key to meeting these challenges. The goal of RAMP-UP Seed is to establish a road map for developing a tool-based methodology in order to increase companies’ sustainability and resilience specifically by targeting the adaptation phase and production facilities.

How do you plan to achieve this? What are the scientific obstacles you must overcome?

Olivier Boissier The project addresses issues related to the topics of production systems and artificial intelligence. The goal is to remedy a lack of methodology guides and tools for strengthening companies’ sustainability and resilience. Two main actions will be prioritized for this purpose during the initial seed stage:

  • An analysis of existing approaches and identification with industrial stakeholders of needs and use cases, which will be conducted jointly with two partners;
  • Development of a proposal for a collaborative project involving Franco-German academic and industrial partners in order to respond to European calls for projects.

From an operational standpoint, work meetings and workshops are held regularly with teams from Mines Saint-Étienne and the TUM in a spirit of collaboration.

Who are the partners involved in this project and what are their respective roles?

KM We started RAMP-UP Seed in partnership with the TUM Institute of Automation and Information Systems with a focus on two main areas: ramp-up management and artificial intelligence. Expertise from the Territoire and IT’M Factory platforms from Institut Henri Fayol, and TUM platforms will be used to develop this dynamic further.

Who will benefit from the methods and tools developed by RAMP-UP Seed?

OB The purpose of the multi-agent optimization and simulation tools and industrial management tools to be developed through this project is to provide decision-making tools for exploring, testing and better managing ramp-up in the manufacturing and service sectors. Special attention will also be given to the health crisis, with a focus on the health sector.

What are the next big steps for the project?

KM RAMP-UP Seed is a seed project. In addition to analyzing current trends, one of the key goals is to develop joint responses to calls for projects in the fields of artificial intelligence and industrial management.

[1] Khaled Medini is a researcher at the Laboratory of Informatics, Modeling and Optimization of Systems (LIMOS), joint research unit UCA/Mines Saint-Étienne/CNRS 6158). Olivier Boissier is a researcher at Hubert Curien Laboratory, joint research unit CNRS 5516/Mines Saint-Étienne).

Interview by Véronique Charlet