NCube/papyrus huggingface dataset:
Transfert interespèces d’électrons par conduction directe via la matrice protéinique exocellulaire dans un biofilm anaérobie granulaire

Effective interspecies electron transfer (IET) is key to the efficient functioning of anaerobic microbial communities. On the other hand, even today there is little information on the mechanisms by which microorganisms cooperate to exchange electrons. Direct interspecies electron transfer (DIET) is a metabolic pathway of IET in which free electrons flow from one microorganism to another without being transported by reduced molecules such as molecular hydrogen or formate. This pathway has been proposed as being present between fermentative and methanogenic populations in the granule during anaerobic digestion. It would involve the extracellular polymeric substances (EPS) of the granule to facilitate the transfer of free electrons. The present study examines these hypotheses. The DIET is divided into two broad categories, DIET mediated by a conductive non-organic material (mDIET) and the biological DIET (bDIET). The latter only involves the cells themselves and their components (pilis, nanowires, etc.). Using anaerobic granules in which Geobacter was not dominant (Geobacter is known for its frequent participation in DIET), the tests carried out with two co-substrates showed that the methanogenic activities of the formate and the hydrogen decreased in the presence of a non-methanogenic co-substrate such as ethanol. This may indicate that the bDIET occurs and competes with hydrogen and formate. In addition, the addition of conductive microparticles, such as stainless steel and granular activated carbon, increases the methanogenic activity in the disintegrated granules as compared to the disintegrated granules without microparticles. These results indicate that syntrophic bacteria from anaerobic sludge, excluding Geobacter species, can also perform mDIET. On the other hand, further to tests with a small reactor designed for the study of mDIET, it was determined that this mechanism may not be exclusive, i.e. alone it can not ensure the survival and growth of the methanogens carrying it out; other IET mechanisms may have to occur in parallel with the mDIET. Acetoclast methanogens, known to perform bDIET, have been enriched in the mDIET assays, as well as some non-acetoclastic methanogens, suggesting a role that is still undefined to date in this pathway. Finally, further to studies of granule EPS, the Methanosaeta concilii proteins were shown to be best represented in all three granular sludges studied, highlighting its role in the formation and maintenance of the anaerobic granule, as well as its stability and effectiveness. Without confirming a specific role for EPS, this study highlights the existence of structures and molecules in the extracellular matrix of the granule that chemically have the ability to participate in the bDIET, such as humic substances and formate dehydrogenases.

Keyphrases: Granule, Direct Interspecies Electron Transfer (DIET), Anaerobic Digestion, Extracellular Polymer Substances (EPS)
Driving with obstructive sleep apnea policies, behaviors and screening measures

Obstructive sleep apnea (OSA) is a serious disorder that occurs when a person's flow of breathing is repeatedly interrupted or reduced during sleep, leading to intermittent drops in blood oxygen saturation. OSA has been characterized as among the most common of medical disorders causing excessive daytime sleepiness. Sleepiness and/or fatigue at the wheel are unquestionably a risk for potentially fatal road accidents and a cause for questioning one’s ability to hold a driver’s license. OSA remains a sleep disorder that is widely debated among traffic policy-makers due to conflicting research findings available to them. The present study reviews the position of leading driving policy-making countries regarding driving competence among individuals with OSA; it proposes a case-by-case assessment approach that considers experiential and behavioural individual differences among individuals with OSA.  This study demonstrates that there is considerable variability both in the driving simulator task, on actual driving behaviors and the number of driving violations among individuals with OSA; this makes it difficult to identify a risk profile in the sample. Fatigue, as an experience distinct from sleepiness, appears to play a significant role in driving behaviors. In addition, the present data do not reveal different driving profiles between drivers with OSA who were either adherent or non-adherent to continuous positive air pressure treatment of the sleep disorder, nor do the data show that treatment decreases fatigue, sleepiness, or the number of self-reported driving violations after 6 months of treatment. Finally, this study introduces a new and more accessible measure that mirrors all possible violations listed by the official government driving agency. This simple tool can be useful for clinicians to help identify a risky driver with OSA and may present an alternative to expensive and time-consuming road tests and driving simulator tasks.

Keyphrases: Fatigue, Obstructive sleep apnea, Driving behaviors, Sleepiness
Thiel embalmed cadaveric tissue : a model for surgical simulation and research

The Royal College of Physicians and Surgeons is currently implementing a major shift from a time based to a competence based curriculum in all medical and surgical specialties. By 2022 the transition is to be complete. The plastic surgery training programs in Canada will have to rethink their curriculum in order to comply with the national directives. Simulation is a cornerstone of the competence based model of resident training as it not only allows residents to safely learn and hone their skill in a setting that is ethical and promotes patient safety, but it allows for objective evaluation of their performance. A recent consensus statement from the Canadian plastic surgery program directors identified 154 essential core procedures for residents to master by the end of their training. We propose the use of the Thiel cadaveric model for high fidelity simulation of plastic surgery procedures. While Thiel cadaveric specimens have been proposed for use in a multitude of specialties, including in plastic surgery for flap dissection and tendon repair, we focused on evaluating the use of the Thiel embalmed specimens on three core procedures: microvascular anastomoses, peripheral nerve repair, and flexor tendon repair. In addition, we designed evaluation instruments for each of these three simulation areas to help grade performance and aid in the feedback/debriefing process. Of the three evaluation instruments, we successfully validated the microvascular evaluation and micro-neurorrhaphy evaluation scales. Both of these scales showed excellent degrees of reliability and reproducibility and correlated well with the level of training and self-declared experience of the subjects. The flexor tendon evaluation scale showed a higher degree of inter-rater variability and, while it shows promise with a larger cohort of participants and additional calibration, it could not be validated fully based on the available data. Additionally, we used the Thiel embalmed cadaveric vessels as a research model for the investigation of new microvascular techniques. Our experience shows the Thiel cadaveric specimens to provide an excellent model for simulating microvascular, peripheral nerve and flexor tendon repairs. We propose evaluation instruments to assist in the implementation of these simulation models in a comprehensive, competence based curriculum in plastic surgery.

Keyphrases: Thiel, simulation, reparation tendon, cadaver, technique de conservation, surgery, plastic surgery, microsurgery, microvascular, microneurorrhaphy, tenorrhaphy, tendon repair, cadaver, preservation technique, embalming technique
Le caractère adaptatif du cerveau âgé sain dans le maintien des habiletés du traitement lexico-sémantique : une approche neurofonctionnelle

Most neurocognitive models that explain how neurofunctional reorganisation supports cognitive performance during aging emphasize the increased involvement of frontal regions, generally known to support executive control, in domains most sensitive to decline with age. An understanding of these adaptative mechanisms can be completed by exploring one of the most well-preserved domains of cognition: that of language, notably in its lexico-semantic aspects. The objective of this thesis is to explore the mechanisms of neurofunctional reorganization underlying the maintenance of semantic word processing abilities during healthy aging. A behavioral and neurofunctional approach to the current study resulted in three studies being conducted, through two principal tasks: a verbal fluency task (study 1) and a semantic categorisation task (studies 2 and 3), both of which required involvement of the executive functions of maintenance and change. The first study demonstrates a strategic reorganisation in the older adult, associated with a neurofunctional adaptive reorganisation at the level of temporal and frontal regions, depending on the strategic processes engaged during word production.  The second study highlights mechanisms of neurofunctional reorganisation influenced by age but equally so by characteristics of the executive profile, operating beyond the frontal regions.  Finally, the third study, which analyses semantic aspects in relation to the degree of control required in maintaining a semantic link, shows that, during aging, neurofunctional adaptation permits the maintenance of the ability to semantically process words, this adaptation varying according to the nature of the task, the cognitive profile characteristics, as well as to the degree of control required during semantic processing. In light of the present research, aging appears to be imbued with a dynamic character, adaptive and evolutionary, which permits the maintenance of semantic processing abilities for words in high-level language tasks, of oral production, and of word comprehension.

Keyphrases: Functional magnetic resonance imaging, Strategic processes, Semantic word processing, Healthy aging, Neurofunctional reorganization, Verbal fluency, Word-matching, Executive control
Role of the orphan nuclear receptor NR5A2 in ovarian function

The orphan nuclear receptor NR5A2, also known as liver receptor homolog 1 (LRH1), is expressed in the ovary, specifically in granulosa cells. Activation and development of ovarian follicles are characterized by the multiplication of granulosa cells, from primordial with only one layer of pregranulosa cells, to pre-ovulatory stage with multiples layers of cuboidal granulosa cells. NR5A2 is a well known actor in regulation of cell proliferation in organs such as the intestine and in conditions such as breast cancer. The hypothesis that NR5A2 regulates follicular development by acting on granulosa cells proliferation and the regulation of the primordial follicle pool activation was tested. To study this transcription factor, a knock-out mouse model characterized by the conditional depletion of NR5A2 in granulosa cells of all follicles (genotype Nr5a2f/f, Amrh2Cre/+) was developed. These female mutant mice, designated as cKO (conditional knock-out), were infertile due to the absence of ovulation. The first part of the study highlighted, in vivo and in vitro, a significant decrease of the number of cells reaching the S phase, where the DNA is replicated. This decrease in the dividing cells was accompanied by significant depletion of genes essential for granulosa cell proliferation, the cyclins D and E among others. Moreover, an effect of the depletion of NR5A2 on granulosa cell proliferation, via its interaction with b-catenin, was demonstrated and proliferation could not be rescued by the ovarian mitogen, estrogen. In terms of the mechanism, it was shown that the expected negative regulation of CDKN1A, a cell cycle inhibitor, did not occur following the depletion of NR5A2. This gene was therefore identified as the main mediator of the abrogation of gonadotropin dependent granulosa cell proliferation observed in the cKO mice. The impact of NR5A2 depletion on primordial follicles population was next studied. In this mouse genotype, there was a several fold increase in the number of primordial follicles, with concomitant upregulation of markers linked to their formation and cell survival. These changes were accompanied by a decrease in the transcripts coding for genes linked to follicle activation. In wild type mice, quantitative analysis by immunocytochemistry confirmed that there are two subpopulations of primordial follicles, one where NR5A2 is expressed in granulosa cells and one where it is absent, the former was judged to be poised for activation, while the latter was quiescent. The cKO mice are characterized by a significant increase in transcript abundance of genes promoting quiescence, support for this concept. We conclude that Nr5a2 plays a role in primordial follicle formation, survival and activation. Taken together these results demonstrate that the orphan nuclear receptor NR5A2 plays a key role in pre and peri-ovulatory events, acting particularly on primordial follicles activation and granulosa cells proliferation

Keyphrases: NR5A2, granulosa cells, proliferation, conditional knockout mouse, ovarian reserve, primordial follicle
Frontal-limbic brain processes in healthy individuals : environmental, epigenetic and behavioral correlates

Neural alterations have been observed in the frontal-limbic circuitry (including the prefrontal cortex, the anterior cingulate cortex, the hippocampus and the amygdala), densely innervated with serotonin, in the individuals with affective disorders. Relationship between the frontal-limbic processes and emotional well-being is affected by the genetics and the environment as well as by their interaction (GxE). Yet, the specific mechanisms are not known to this day. The aim of the present thesis was to study the environmental effects on and the relevance of DNA methylation (a physiological mechanism underpinning the GxE influences on gene expression) for the frontal-limbic brain processes in healthy individuals. In the first study, association between the daily-life mood (assessed using a daily diary method) and the brain processes was studied. In the second study, association between the peripheral DNA methylation in the serotonin transporter [SLC6A4] gene (linked to emotional functioning), derived from different tissues, and the brain processes was examined. In the third study, we examined whether the association between the peripheral SLC6A4 gene methylation and the brain processes was independent of the genetic variation (using a monozygotic twin sample). Briefly, daily-life negative and positive mood was positively associated with the resting-state functional connectivity between posterior and anterior cingulate cortices. The SLC6A4 gene methylation was positively associated with the prefrontal cortical volume when derived from blood, saliva and buccal cells; buccal-derived SLC6A4 gene methylation was also found to be positively associated with the anterior cingulate cortical volume and the resting-state functional connectivity between parietal areas and the anterior cingulate cortex. The peripheral SLC6A4 gene methylation was also positively associated with the orbitofrontal cortical activity as well as with the functional connectivity between the amygdala, the orbitofrontal and the anterior cingulate cortices in response to negative emotional stimuli, regardless of individuals’ DNA sequence. Overall, current findings might indicate that brain function and structure in the frontal-limbic regions, particularly in the anterior cingulate and the prefrontal cortices, are positively associated with the daily-life mood and the peripheral SLC6A4 gene methylation in healthy individuals. Additionally, the relationship between these frontal-limbic processes and peripheral SLC6A4 gene methylation appear to be largely driven by the environmental influences. Also, current results suggest that buccal cells may be a suitable peripheral tissue for studying the SLC6A4 gene methylation and its related neural processes. Future studies are necessary to validate these results in the clinical population as well as in the individuals exposed to differential environmental conditions.

Keyphrases: Brain, Emotion, Serotonin transporter gene, DNA methylation, Peripheral tissue, Brain imaging, Mood, Healthy
Adaptations neuromusculaires du tronc dans différents contextes de perturbations mécaniques et physiologiques

Postural stability is continuously challenged, sometimes suddenly, by external forces applied in many directions and continuously triggering postural adjustments. When spinal stability is challenged by a sudden external perturbation, neuromuscular responses occur, such as reflexes, in order to maintain a certain performance level in everyday functional tasks. Such neuromuscular responses have also been investigated under the influence of muscle fatigue, as well as spinal tissue creep and experimental low back pain. However, contradictory results have been observed between studies making it difficult to characterize the neuromuscular responses of trunk. Neuromuscular adaptations, such as attenuation of reflex activation, have also been observed across the repetition of the same unexpected external perturbations. This suggest that the central nervous system (CNS) is able to adapt neuromuscular responses based on a previous experience of an external perturbation even when it is unexpected. This raise the question whether, based on a previous experience, the CNS will be able to generate proper motor responses when spinal stability is challenged by the influence of experimental back pain, muscle fatigue, or spinal tissue creep. Therefore, the main objective of this thesis was to identify and characterize motor adaptations in healthy participants when they are submitted to unexpected trunk perturbations in different contexts (back muscle fatigue, spinal tissue creep, and experimental back pain). Healthy participants were recruited through three different studies. Participants were submitted to 30 sudden external perturbations before and after a protocol of low back muscle fatigue (study 1), or before and after a spinal tissue creep deformation (study 2), or with and without experimental low back pain (study 3). Trunk neuromuscular responses were measured using high-density surface electromyography and trunk motion analysis. The results of this thesis show that participants were able to adapt their neuromuscular responses using different strategies. Participants were able to attenuate reflex responses when experiencing a series of unexpected trunk perturbations under the influence of creep deformation or experimental back pain. On the other hand, the lack of erector spinae EMG reflex attenuation across perturbation trials was observed under the influence of muscle fatigue. These projects were funded through the Natural Sciences and Engineering Research Council of Canada (NSERC) in the form of both a scholarship and a discovery grant.

Keyphrases: Spinal stability, Motor variability, High-density electromyography, Muscle fatigue, Pain, Creep
Obesity prevention policies : the art and science of ending an epidemic

Theory grounded research on the policy process related to obesity prevention is limited. Most of the existing research fails to explain policy decisions. The how and why of policy making remain unanswered. Owing to the increased political attention to “globesity”, many governments have attempted to intervene to halt or reverse the obesity epidemic. There is a gap between policy recommendations and the prevailing policy environment owing to the “policy cacophony” that characterises obesity policy.  We used a case study research design to explain the development and the adoption of a six-year Governmental Action Plan (GAP) on the prevention of weight-related problems and the promotion of healthy lifestyles in Quebec, Canada. We developed an innovative conceptual framework combining the Advocacy Coalition Framework with a political analysis model based on the theory of the strategic actor. We conducted semi-structured open-ended interviews with key informants from various governmental and non-governmental departments and institutions involved in GAP advocacy and development. Policy related documents completed our data sources.  Our findings showed that policy adoption was the result of interrelated political and contextual factors and focusing events, intertwined with policy and goal-oriented strategies that contributed to a negotiated agreement between advocacy coalitions. The whole process was influenced by systematic knowledge utilization by coalitions and learning within democratic deliberative forums that helped overcome “policy cacophony”. The advocacy of a think tank advanced the process through changing the dominant policy narrative and altering policy stakeholders’ awareness.  Policy process theories are powerful tools to study the complexity of decision-making, explain policy change as well as inaction on complex policy issues. There is a need to better equip public health policy stakeholders with an improved understanding of the policy making process. This case study will inform policy makers, bureaucrats, public health professionals and other professionals interested in advancing obesity prevention policies. Future research should aim to promote prospective analysis of policy making to further inform policy advocacy and advance the policy process. Comparing similar policies across jurisdictions, and different yet interrelated policies within the same jurisdiction is another avenue for future policy process research.

Keyphrases: Obesity policy, Advocacy, Agenda-setting, Policy decisions, Health policy formulation, Policy adoption, Knowledge utilization, Policy theory, Public health nutrition
Le rôle du système rénine-angiotensine et de la différence liée au sexe dans la fibrillation auriculaire chez la souris

Atrial fibrillation is the most common sustained cardiac arrhythmia. Indeed, atrial fibrillation affects 1 to 2 % of the general population and up to 10 % of the population older than 80 years old. Besides being an important source of cardiovascular complications, morbidity and mortality, atrial fibrillation represents more than one third of all hospitalisations related to cardiovascular diseases. Many risk factors can lead to atrial fibrillation occurence, such as male sex and age, but also clinical disorders such as heart failure, hypertension, diabetes, and endurance training Therefore, the goal of this thesis is to study the association between the renin-angiotensin system, male sex and the prevalence of atrial fibrillation. Experiences at the cellular (electrophysiology) and molecular level will be done to evaluate the role of electrophysiological and structural remodeling in the development of atrial fibrillation. Briefly, the results show that a cardiac specific overexpression of angiotensin II type 1 receptors causes a decrease in the expression of Na+ currents and connexin 40 leading to the disruption of atrial conduction. Of note, male mice were two times as susceptible to atrial fibrillation events than female and this prevalence is associated with a lower expression of connexin 40. However, following orchiectomy, the number of atrial fibrillation events and the expression level of connexin 40 gene reached similar values as those found in the female mice. In summary, this reduction in conduction velocity caused by a reduction of connexin 40 and Na+ currents can lead to an increased risk of atrial fibrillation due to the occurence of focal ectopic activity and re-entry phenomenon. Furthermore, we showed that androgen seems to be responsible for the decreased connexin 40 expression associated with the higher prevalence of atrial fibrillation observed in men. Thus, these results might allow the development of specific therapies based on sex or specific to certain forms of atrial fibrillation.

Keyphrases: atrial fibrillation, electrophysiology, androgen, connexin, angiotensin II