HAL Université de Toulouse, et Toulouse INP
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Vascular leakage during circulatory failure: physiopathology, impact and treatments
No full textInternational audienceVascular leakage has emerged as a major factor during circulatory failure. Triggered by the inflammatory process following the recognition of both pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), it worsens circulatory failure through the hypovolemia it induces. It may also crucially participate in secondary microcirculation disorders and organ dysfunctions, due to interstitial edema resulting from extravascular fluid accumulation. Accordingly, fluid balance, i.e., the difference between fluid intake and output, is directly related with outcomes during the different types of shock. Moreover, controlling vascular leakage had beneficial effects in various animal models of circulatory failure. However, despite promising preclinical findings, no routine drug is currently available to control vascular leakage in humans. This review depicts the mechanisms involved in the maintenance of a quiescent endothelium and those implicated in the destabilization of its barrier function in various forms of shocks. It further describes available tools to explore vascular leakage and the most advanced treatments under development
Tutorial videos and a serious game as innovative training resources for atmospheric science & climate change
No full textDoes Methyl-CpG-binding domain protein 2 (MBD2) repress gene transcription?: A meta-analysis of transcriptome studies after MBD2 perturbation
No full textInternational audienceContext: Methyl-CpG-binding domain protein 2 (MBD2) binds methylated CpG in vitro or in vivo, and recruit the NuRD repressive complex. MBD2 is thought to play a role in the transcriptional repression of genes with a methylated promoter in vertebrates. However in surprising study, a quadruple knock-out of MBD2 along with MECP2, MBD1, and MBD4 lead to no widespread up-regulation of genes with a methylated promoters.Methods: A meta-analysis of transcriptome studies after MBD2 perturbation was carried out to investigate the contradictory results observed in the literature. Twenty-seven datasets were identified from 17 different studies in human or mouse, including 26 datasets with MBD2 removal and one dataset with MBD2 over-expression. The number of up-regulated or down-regulated genes was identified for each study using a differentially expressed gene reanalysis with {limma}, using four different null-hypothesis thresholds of fold-change. MBD2 perturbation was confirmed for 19 of the 26 datasets.Results: Eleven of the 18 datasets (61%) with MBD2 removal were showing more gene over-expressions than down-regulations, while the other datasets were showing more down-regulations than over-expressions (4 datasets), or balanced profiles (3 datasets). The number of up-regulated genes after MBD2 removal was globally estimated as 3.2 times (CI 95%: 1.4; 7.3) more than the number of down-regulated genes for a fold change threshold of 2. The only datasets with MBD2 over-expression had more down-regulated genes than upregulated genes. There was no obvious association between the role of MBD2 as a gene repressor and the species, the tissues / cell types, its oncogenic status, nor the perturbation method.Conclusion: This meta-analysis supports a role for MBD2 in gene repression
Unified Analytical Model from Radial to Axial Permanent Magnet Machine: Conical Flux Machine
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The OMEGA-Py Python module: a complete and easy way to work with OMEGA/MEX observations
No full textInternational audienceOMEGA-Py [1,2] is a Python 3 module dedicated to the scientific use of data provided by the Observatoire pour la Minéralogie, l’Eau, les Glaces et l’Activité (OMEGA) instrument onboard the ESA Mars Express (MEx) orbiter [3]. It has been developed as an alternative to the IDL routines of the OMEGA legacy software provided by the instrument team for the past 20 years [4] and its validation by comparison with the results of the IDL routines has been endorsed by the OMEGA PI. The module notably includes a Python reimplementation of the most recent release of the IDL OMEGA software (v10, SOFT10) [4], which performs the reading, calibration, and reduction of the level 1B data publicly available on the ESA PSA to produce level 2A data (calibrated reflectances cubes) that can be used for the scientific analysis. In addition, the module also includes built-in functions to perform the atmospheric and thermal corrections of the data (using previously published methods) and graphic tools dedicated to the OMEGA hyperspectral data including interactive visualization of the cubes or generation of composite OMEGA maps. Also, since the release of its version 3.0 in October 2023 (currently in version 3.2, released on January 2025), OMEGA-Py is now distributed as part of the official OMEGA software ecosystem (https://www.ias.u-psud.fr/omega/software.html)
Étude de l'influence des phénomènes thermomécaniques générés par l'interaction faisceau laser matière sur la microstructure des revêtements élaborés par SLM : une approche multi-physique (Thèse sous embargo)
No full textThe aim of this study is to investigate the advection/convection mechanisms that occur during the additive manufacturing process on dissimilar materials. More specifically for this research, a group of materials which have distinct thermophysical characteristics, but which have the advantage of being perfectly miscible at high temperatures : - C35 (or XC38) steel is a material frequently used in manufacturing tools - Cobalt-Chromium-Molybdenum alloy for applications requiring high resistance to wear and high temperatures. The first part of this study focuses on the description of the stellite alloy, as it is barely characterized in terms of its thermal characteristics, especially at high temperatures. The multiphysics numerical models developed in the study provide access to a large amount of information on the behavior of the molten region as a function of the parameters of the FA L-PBF machine, with reference to a relatively small amount of initial data and a few basic assumptions. Multiphysics modeling is used to replicate the shape of the molten zone, visualize the flow of liquid metal and map the distribution of the various elements, taking into account the experimental results. To implement these manufacturing process models, we use the commercial simulation software COMSOL Multiphysics® . A series of models have been developed to simulate temperature variations, convective movements and chemical mixing. All these models enable us to predict the results of the various phenomena induced as a function of operating conditions.Cette étude vise à étudier les mécanismes d'advections/convections qui se produisent lors du processus de fabrication additive L-PBF sur des matériaux différents. Plus spécifiquement pour cette recherche, un ensemble de matériaux qui ont des caractéristiques thermophysiques distinctes, mais qui ont l'avantage d'être parfaitement miscibles à haute température : - l'acier C35 (ou XC38) qui est un matériau usuellement utilisé pour l'outillage- l'alliage stellite (composé de cobalt, de chrome et de molybdène) est un alliage adéquat pour les applications nécessitant de fortes caractéristiques en termes d'usure et de bonne tenue en température. Le premier aspect de cette étude se concentre sur la description de l'alliage de stellite, car il est très peu caractérisé en ce qui concerne ses caractéristiques thermiques, notamment à des températures élevées. Pour cela, des caractérisations sur les propriétés thermiques de la poudre ont été effectuées pour la capacité calorifique, la diffusivité thermique et la masse volumique de la poudre. En complément de ces mesures, une attention plus particulière sur les caractérisations thermo-optiques de la poudre et de l'alliage de stellite a été menée, notamment sur l'absorptivité et l'émissivité. L'utilisation des modèles numériques multiphysiques développés lors de cette étude permet d'accéder rapidement à une grande quantité d'informations sur le comportement de la zone fondue en fonction des paramètres de la machine FA L-PBF en se référant à un nombre de données de départ relativement restreint et à quelques hypothèses basiques. La modélisation multiphysique permet de reproduire la forme de la zone fondue, de visualiser les flux de métal liquide et de cartographier la répartition des différents éléments en tenant compte des résultats expérimentaux. Afin de mettre en œuvre ces modèles de procédé de fabrication, nous utilisons le logiciel de simulation commercial COMSOL Multiphysics. On a développé une série de modèles qui simulent les variations de température, les mouvements convectifs et le mélange des substances chimiques. Tous ces modèles permettent de prévoir les résultats des divers phénomènes induits en fonction des conditions opératoires
Numerical modeling of electric arc in a low voltage breaking chamber
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Light emission from a hybrid plasmonic-excitonic STM tunneling junction
No full textInternational audienceThis work focuses on light emission from the nanojunction formed by the tip and a surface in a Scanning Tunneling Microscopy (STM) configuration. The nanojunction includes an ultrathin quantum well made of a single monolayer of a transition metal dichalcogenide material deposited on a gold surface. In this specific configuration, inelastic tunneling of electrons, induced by a bias voltage applied to the tip-surface gap of the STM, excites both Localized Surface Plasmon Polaritons (LSPPs) and excitons. These electromagnetic modes hybridize in this optical nanocavity, producing complex light emission spectra with both plasmonic and excitonic characteristics that depend on the tunneling parameters and the surface roughness. We model the luminescence process as radiative emission triggered by electron tunneling, and we estimate the quantum efficiency as the number of tunneling electrons required to initiate a single exciton recombination and subsequent photon emission. The calculated emission spectra describe the experimental observations well and allow for a thorough understanding of the fundamental physical processes behind light emission in a hybrid plasmonic-excitonic STM nanojunction
Effets du spectre lumineux sur le temps de floraison du gombo abelmoschus esculentus
No full textInternational audienceCONCLUSIONRésultats v Les plants de gombo ont été cultivés pendant 75 jours sous un éclairage naturel et artificiel. v La lumière artificielle a impliqué trois traitements : la lumière bleue B (445 nm), la lumière rouge R (660 nm) et l'alternance de lumière rouge/bleue tous les 3 jours (R3B3). v La lumière naturelle comprenait deux configurations : sous une bâche blanche transparente (serre) et à l'extérieur. Floraison du gombo sous éclairage bleu (A), rouge (B), rouge-bleu alterné (C), sous serre (D) et à l'extérieur (E) Contexte: v La lumière est un facteur environnemental clé influençant le développement des plantes, notamment à travers trois dimensions essentielles : l'intensité, la photopériode et la qualité spectrale. Si l'intensité lumineuse et la photopériode ont fait l'objet de nombreuses recherches et ont conduit au développement de technologies de contrôle de la floraison, l'impact de la qualité de la lumière reste encore partiellement élucidé. Le gombo (Abelmoschus esculentus) est une plante de jours courts quantitative (facultative), ce qui signifie que sa floraison est favorisée par des jours courts, sans en dépendre strictement. Il constitue ainsi un matériel expérimental pertinent pour l'étude des effets de la lumière sur la floraison. Objectifs: Ø Évaluer l'impact des différents spectres lumineux sur le temps de floraison du gombo, sous des conditions d'éclairage contrôlées et naturelles.. Ø Déterminer le nombre minimal de cycles photopériodiques SD nécessaires après un certain stade pour induire la floraison.</div
Thioether–NHC bidentate manganese complexes as efficient phosphine-free catalysts for hydrogenation at room temperature
No full textInternational audienceA series of four original phosphine-free thioether–NHC manganese complexes have been synthesised and fully characterized. These complexes have been applied as efficient catalysts for the hydrogenation of alkenes and ketones at room temperature, with low catalyst loadings (TON up to 900)