Relation entre les malocclusions dento-squelettiques et les scolioses idiopathiques adolescentes : un projet pilote

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Complex dynamics for the study of neural activity in the human brain

Congrès sous l’égide de la Société Française de Génie Biologique et Médical (SFGBM).National audienceNeural mass modeling is a part of computational neuroscience that was developed to study the general behavior of interacting neuronal populations. This type of mesoscopic model is able to generate output signals that are comparable with experimental data such as electroencephalograms. Classically, neural mass models consider two interconnected populations. One interaction have been modeled in two differents ways. In this work we propose and analyze a neural mass model embedding both approaches and compare the generated time series to real data

La gestion alternative des eaux pluviales permet-elle une maîtrise efficace des flux de micropolluants? Retour d'expérience des projets Matriochkas, MicroMégas et Roulépur

Novatech 2019, LYON, FRANCE, 01-/07/2019 - 05/07/2019The pooling of results from three French projects (Matriochkas, MicroMégas and Roulépur), within the framework of a working group on methodological harmonisation, makes it possible to analyse the performance of a wide range of stormwater control measures (SCMs) in terms of micropollutant load reduction. Data covers 12 management systems, in 9 different urban contexts. The results highlight the diversity of runoff contamination levels and of their distribution between dissolved and particulate phases. They show significant reductions in particulate pollutants for all filtration-based systems, and less for those that only allow sedimentation. Performance is more limited for the dissolved phase, for which concentration reduction is limited and significant load reductions are only achieved due to a reduction in runoff volumes in structures promoting evapotranspiration.La mise en commun de résultats issus des projets français Matriochkas, MicroMégas et Roulépur, dans le cadre d'un groupe de travail d'échanges et d'harmonisation méthodologiques, permet d'analyser l'efficacité de la gestion alternative des eaux pluviales en termes de réduction des flux de micropolluants, pour 12 dispositifs de gestion et 9 contextes urbains différents. Les résultats soulignent la diversité des niveaux de contamination des eaux de ruissellement, et de leur distribution entre phases dissoutes et particulaires. Ils démontrent des abattements importants des polluants particulaires pour l'ensemble des systèmes basés sur la filtration, et moindre pour ceux ne permettant que la sédimentation. Les performances sont plus limitées pour les concentrations dissoutes, de sorte que seul un abattement des volumes de ruissellement, dans les ouvrages favorisant l'évapotranspiration, permet une réduction significative des flux de micropolluants dissou

Le développent d'un guide méthodologique pour l'évaluation des performances des ouvrages de maîtrise à la source des eaux pluviales

Novatech 2019, LYON, FRANCE, 01-/07/2019 - 05/07/2019Evaluating the performance of sustainable drainage systems (SuDS) in a field context presents a number of methodological problems. For this reason, as a part of three French research projects focused on this type of evaluation, Matriochkas, Micromegas and Roulepur, a working group on methodological harmonisation was established in order to facilitate the inter-comparison of results between the projects and propose a methodological guideline for practitioners carrying out such evaluations. The guideline proposes an approach where performance is evaluated with respect to a service function that the SuDS aims to achieve, itself identified from local issues. Its first section presents the various service functions which may be assigned to these devices. Next, performance indicators are defined for a selection of the identified service functions, common within the French context and studied as a part of the three projects. Three categories of indicators are identified: hydrologic indicators (relative to water flows), pollutant indicators and socio-technical indicators. Examples of instrumentation and of the application of the proposed indicators drawn from the experience of the three projects are also presented.L'évaluation in situ des performances des ouvrages de maîtrise à la source des eaux pluviales pose un grand nombre de questions d'ordre méthodologique. Ainsi, dans le cadre de trois projets de recherche français dédiés à ce type d'évaluation, Matriochkas, Micromegas et Roulépur, un groupe de travail sur l'harmonisation des méthodes a été constitué afin de faciliter l'inter-comparaison des résultats issus des projets, mais aussi de rédiger un guide méthodologique à destination des acteurs opérationnels pouvant être amenés à faire ce type d'étude. Ce guide propose une démarche où la performance est évaluée pour chaque fonction de service visée pour l'ouvrage, en réponse à des enjeux locaux. La première partie du guide détaille les fonctions de service pouvant être attendues de ce type d'ouvrage. Ensuite, des indicateurs de performance sont déclinés pour une sélection de fonctions de service couramment rencontrées dans le contexte français et qui ont pu être abordées au cours des projets. Ces indicateurs se regroupent en trois catégories: les indicateurs hydrologiques (relatifs aux flux d'eau), les indicateurs pollutifs (relatifs aux polluants) et les indicateurs sociotechniques. Le guide s'appuie sur des exemples issus des trois projets pour présenter des cas pratiques de dispositifs métrologiques et d'application des indicateurs proposés

A novel microarray approach reveals new tissue-specific signatures of known and predicted mammalian microRNAs

Microarrays to examine the global expression levels of microRNAs (miRNAs) in a systematic in-parallel manner have become important tools to help unravel the functions of miRNAs and to understand their roles in RNA-based regulation and their implications in human diseases. We have established a novel miRNA-specific microarray platform that enables the simultaneous expression analysis of both known and predicted miRNAs obtained from human or mouse origin. Chemically modified 2′-O-(2-methoxyethyl)-(MOE) oligoribonucleotide probes were arrayed onto Evanescent Resonance (ER) microchips by robotic spotting. Supplementing the complementary probes against miRNAs with carefully designed mismatch controls allowed for accurate sequence-specific determination of miRNA expression profiles obtained from a panel of mouse tissues. This revealed new expression signatures of known miRNAs as well as of novel miRNAs previously predicted using bioinformatic methods. Systematic confirmation of the array data with northern blotting and, in particular, real-time PCR suggests that the described microarray platform is a powerful tool to analyze miRNA expression patterns with rapid throughput and high fidelity

A prospective, observational study of fidaxomicin use for Clostridioides difficile infection in France.

To describe the characteristics, management and outcomes of hospitalised patients with Clostridioides difficile infection (CDI) treated with and without fidaxomicin. This prospective, multicentre, observational study (DAFNE) enrolled hospitalised patients with CDI, including 294 patients treated with fidaxomicin (outcomes recorded over a 3-month period) and 150 patients treated with other CDI therapies during three 1-month periods. The primary endpoint was baseline and CDI characteristics of fidaxomicin-treated patients. At baseline, the fidaxomicin-treated population included immunocompromised patients (39.1%) and patients with severe (59.2%) and recurrent (36.4%) CDI. Fidaxomicin was associated with a high rate of clinical cure (92.2%) and low CDI recurrence (16.3% within 3 months). Clinical cure rates were ≥90% in patients aged ≥65 years, those receiving concomitant antibiotics and those with prior or severe CDI. There were 121/296 (40.9%) patients with adverse events (AEs), 5.4% with fidaxomicin-related AEs and 1.0% with serious fidaxomicin-related AEs. No fidaxomicin-related deaths were reported. Fidaxomicin is an effective and well-tolerated CDI treatment in a real-world setting in France, which included patients at high risk of adverse outcomes.Trial registration: Description of the use of fidaxomicin in hospitalised patients with documented Clostridium difficile infection and the management of these patients (DAFNE), NCT02214771, www.ClinicalTrials.gov

Spatial Regulation of Membrane Fusion Controlled by Modification of Phosphoinositides

Membrane fusion plays a central role in many cell processes from vesicular transport to nuclear envelope reconstitution at mitosis but the mechanisms that underlie fusion of natural membranes are not well understood. Studies with synthetic membranes and theoretical considerations indicate that accumulation of lipids characterised by negative curvature such as diacylglycerol (DAG) facilitate fusion. However, the specific role of lipids in membrane fusion of natural membranes is not well established. Nuclear envelope (NE) assembly was used as a model for membrane fusion. A natural membrane population highly enriched in the enzyme and substrate needed to produce DAG has been isolated and is required for fusions leading to nuclear envelope formation, although it contributes only a small amount of the membrane eventually incorporated into the NE. It was postulated to initiate and regulate membrane fusion. Here we use a multidisciplinary approach including subcellular membrane purification, fluorescence spectroscopy and Förster resonance energy transfer (FRET)/two-photon fluorescence lifetime imaging microscopy (FLIM) to demonstrate that initiation of vesicle fusion arises from two unique sites where these vesicles bind to chromatin. Fusion is subsequently propagated to the endoplasmic reticulum-derived membranes that make up the bulk of the NE to ultimately enclose the chromatin. We show how initiation of multiple vesicle fusions can be controlled by localised production of DAG and propagated bidirectionally. Phospholipase C (PLCγ), GTP hydrolysis and (phosphatidylinsositol-(4,5)-bisphosphate (PtdIns(4,5)P2) are required for the latter process. We discuss the general implications of membrane fusion regulation and spatial control utilising such a mechanism

Patent Foramen Ovale Closure or Anticoagulation vs. Antiplatelets after Stroke

BACKGROUND Trials of patent foramen ovale (PFO) closure to prevent recurrent stroke have been inconclusive. We investigated whether patients with cryptogenic stroke and echocardiographic features representing risk of stroke would benefit from PFO closure or anticoagulation, as compared with antiplatelet therapy. METHODS In a multicenter, randomized, open-label trial, we assigned, in a 1:1:1 ratio, patients 16 to 60 years of age who had had a recent stroke attributed to PFO, with an associated atrial septal aneurysm or large interatrial shunt, to transcatheter PFO closure plus long-term antiplatelet therapy (PFO closure group), antiplatelet therapy alone (antiplatelet-only group), or oral anticoagulation (anticoagulation group) (randomization group 1). Patients with contraindications to anticoagulants or to PFO closure were randomly assigned to the alternative noncontraindicated treatment or to antiplatelet therapy (randomization groups 2 and 3). The primary outcome was occurrence of stroke. The comparison of PFO closure plus antiplatelet therapy with antiplatelet therapy alone was performed with combined data from randomization groups 1 and 2, and the comparison of oral anticoagulation with antiplatelet therapy alone was performed with combined data from randomization groups 1 and 3. RESULTS A total of 663 patients underwent randomization and were followed for a mean (+/- SD) of 5.3 +/- 2.0 years. In the analysis of randomization groups 1 and 2, no stroke occurred among the 238 patients in the PFO closure group, whereas stroke occurred in 14 of the 235 patients in the antiplatelet-only group (hazard ratio, 0.03; 95% confidence interval, 0 to 0.26; P<0.001). Procedural complications from PFO closure occurred in 14 patients (5.9%). The rate of atrial fibrillation was higher in the PFO closure group than in the antiplatelet-only group (4.6% vs. 0.9%, P = 0.02). The number of serious adverse events did not differ significantly between the treatment groups (P = 0.56). In the analysis of randomization groups 1 and 3, stroke occurred in 3 of 187 patients assigned to oral anticoagulants and in 7 of 174 patients assigned to antiplatelet therapy alone. CONCLUSIONS Among patients who had had a recent cryptogenic stroke attributed to PFO with an associated atrial septal aneurysm or large interatrial shunt, the rate of stroke recurrence was lower among those assigned to PFO closure combined with antiplatelet therapy than among those assigned to antiplatelet therapy alone. PFO closure was associated with an increased risk of atrial fibrillation

Development of a Questionnaire for the Search for Occupational Causes in Patients with Non-Hodgkin Lymphoma: The RHELYPRO Study

Non-Hodgkin lymphoma (NHL), multiple myeloma and chronic lymphocytic leukemia are possibly related to environmental and/or occupational exposure. The primary objective of this study was to develop a questionnaire for screening patients with these blood disorders who might benefit from a specialized consultation for possible recognition of the disease as an occupational disease. The study included 205 subjects (male gender, 67.3%; mean age, 60 years; NHL, 78.5%). The questionnaire performed very satisfactorily in identifying the exposures most frequently retained by experts for their potential involvement in the occurrence of NHL. Its sensitivity and specificity in relation to the final expertise were 96% and 96% for trichloroethylene, 85% and 82% for benzene, 78% and 87% for solvents other than trichloroethylene and dichloromethane, 87% and 95% for pesticides, respectively. Overall, 15% of the subjects were invited to ask National Social Insurance for compensation as occupational disease. These declarations concerned exposure to pesticides (64%), solvents (trichloroethylene: 29%; benzene: 18%; other than chlorinated solvents: 18%) and sometimes multiple exposures. In conclusion, this questionnaire appears as a useful tool to identify NHL patients for a specialized consultation, in order to ask for compensation for occupational disease

The Comet Interceptor Mission

Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ΔV capability of 600 ms−1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule