Nuclear data sensitivity and uncertainty assessment of sodium voiding reactivity coefficients of an ASTRID-like sodium fast reactor

The EU 7th Framework ESNII+ project was launched in 2013 with the strategic orientation of preparing ESNII for Horizon 2020. ESNII stands for the European Industrial Initiative on Nuclear Energy, created by the European Commission in 2010 to promote the development of a new generation of nuclear systems in order to provide a sustainable solution to cope with Europe’s growing energy needs while meeting the greenhouse gas emissions reduction target. The designs selected by the ESNII+ project are technological demonstrators of Generation-IV systems. The prototype for the sodium cooled fast reactor technology is ASTRID (standing for Advanced Sodium Technological Reactor for Industrial Demonstration), which detailed design phase is foreseen to be initiated in 2019. The ASTRID core has a peculiar design which was created in order to tackle the main neutronic challenge of sodium cooled fast reactors: the inherent overall positive reactivity feedback in case of sodium voiding occurring in the core. Indeed, the core is claimed by its designers to have an overall negative reactivity feedback in this scenario. This feature was demonstrated for an ASTRID-like core within the ESNII+ framework studies performed by nine European institutions. In order to shift the paradigm towards best-estimate plus uncertainties, the nuclear data sensitivity analysis and uncertainty propagation on reactivity coefficients has to be carried out. The goal of this work is to assess the impact of nuclear data uncertainties on sodium voiding reactivity feedback coefficients in order to get a more complete picture of the actual safety margins of the ASTRID low void-core design. The nuclear data sensitivity analysis is performed in parallel using SCALE TSUNAMI-3D and the newly developed GPT SERPENT 2 module. A comparison is carried out between the two methodologies. Uncertainty on the sodium reactivity feedbacks is then calculated using TSAR module of SCALE and the necessary safety margins conclusions are drawn

A Serum Factor Induces Insulin-Independent Translocation of GLUT4 to the Cell Surface which Is Maintained in Insulin Resistance

In response to insulin, glucose transporter GLUT4 translocates from intracellular compartments towards the plasma membrane where it enhances cellular glucose uptake. Here, we show that sera from various species contain a factor that dose-dependently induces GLUT4 translocation and glucose uptake in 3T3-L1 adipocytes, human adipocytes, myoblasts and myotubes. Notably, the effect of this factor on GLUT4 is fully maintained in insulin-resistant cells. Our studies demonstrate that the serum-induced increase in cell surface GLUT4 levels is not due to inhibition of its internalization and is not mediated by insulin, PDGF, IGF-1, or HGF. Similarly to insulin, serum also augments cell surface levels of GLUT1 and TfR. Remarkably, the acute effect of serum on GLUT4 is largely additive to that of insulin, while it also sensitizes the cells to insulin. In accordance with these findings, serum does not appear to activate the same repertoire of downstream signaling molecules that are implicated in insulin-induced GLUT4 translocation. We conclude that in addition to insulin, at least one other biological proteinaceous factor exists that contributes to GLUT4 regulation and still functions in insulin resistance. The challenge now is to identify this factor

Rosiglitazone increases cell surface GLUT4 levels in 3T3-L1 adipocytes through an enhancement of endosomal recycling

International audienc

Nuclear data sensitivity and uncertainty assessment of sodium voiding reactivity coefficients of an ASTRID-like sodium fast reactor

The EU 7th Framework ESNII+ project was launched in 2013 with the strategic orientation of preparing ESNII for Horizon 2020. ESNII stands for the European Industrial Initiative on Nuclear Energy, created by the European Commission in 2010 to promote the development of a new generation of nuclear systems in order to provide a sustainable solution to cope with Europe’s growing energy needs while meeting the greenhouse gas emissions reduction target. The designs selected by the ESNII+ project are technological demonstrators of Generation-IV systems. The prototype for the sodium cooled fast reactor technology is ASTRID (standing for Advanced Sodium Technological Reactor for Industrial Demonstration), which detailed design phase is foreseen to be initiated in 2019. The ASTRID core has a peculiar design which was created in order to tackle the main neutronic challenge of sodium cooled fast reactors: the inherent overall positive reactivity feedback in case of sodium voiding occurring in the core. Indeed, the core is claimed by its designers to have an overall negative reactivity feedback in this scenario. This feature was demonstrated for an ASTRID-like core within the ESNII+ framework studies performed by nine European institutions. In order to shift the paradigm towards best-estimate plus uncertainties, the nuclear data sensitivity analysis and uncertainty propagation on reactivity coefficients has to be carried out. The goal of this work is to assess the impact of nuclear data uncertainties on sodium voiding reactivity feedback coefficients in order to get a more complete picture of the actual safety margins of the ASTRID low void-core design. The nuclear data sensitivity analysis is performed in parallel using SCALE TSUNAMI-3D and the newly developed GPT SERPENT 2 module. A comparison is carried out between the two methodologies. Uncertainty on the sodium reactivity feedbacks is then calculated using TSAR module of SCALE and the necessary safety margins conclusions are drawn

Nuclear data sensitivity and uncertainty assessment of sodium voiding reactivity coefficients of an ASTRID-like sodium fast reactor

The EU 7th Framework ESNII+ project was launched in 2013 with the strategic orientation of preparing ESNII for Horizon 2020. ESNII stands for the European Industrial Initiative on Nuclear Energy, created by the European Commission in 2010 to promote the development of a new generation of nuclear systems in order to provide a sustainable solution to cope with Europe’s growing energy needs while meeting the greenhouse gas emissions reduction target. The designs selected by the ESNII+ project are technological demonstrators of Generation-IV systems. The prototype for the sodium cooled fast reactor technology is ASTRID (standing for Advanced Sodium Technological Reactor for Industrial Demonstration), which detailed design phase is foreseen to be initiated in 2019. The ASTRID core has a peculiar design which was created in order to tackle the main neutronic challenge of sodium cooled fast reactors: the inherent overall positive reactivity feedback in case of sodium voiding occurring in the core. Indeed, the core is claimed by its designers to have an overall negative reactivity feedback in this scenario. This feature was demonstrated for an ASTRID-like core within the ESNII+ framework studies performed by nine European institutions. In order to shift the paradigm towards best-estimate plus uncertainties, the nuclear data sensitivity analysis and uncertainty propagation on reactivity coefficients has to be carried out. The goal of this work is to assess the impact of nuclear data uncertainties on sodium voiding reactivity feedback coefficients in order to get a more complete picture of the actual safety margins of the ASTRID low void-core design. The nuclear data sensitivity analysis is performed in parallel using SCALE TSUNAMI-3D and the newly developed GPT SERPENT 2 module. A comparison is carried out between the two methodologies. Uncertainty on the sodium reactivity feedbacks is then calculated using TSAR module of SCALE and the necessary safety margins conclusions are drawn

Numerical and Experimental Investigation of A Three-Axis Free Rotation Wind Tunnel Model

International audienceThe current need of improving performance in terms of control and aerodynamic efficiency of ammunitions leads to the necessity of performing accurate flying geometry characterizations. Therefore, new investigation methods are developed in order to increase the aerodynamic knowledge. Free flight measurements experiments are the most common way to obtain dynamic aerodynamic coefficients. However, they do not always allow neither easy nor perfect measurements conditions. Currently ISL develops a stereovision method based wind-tunnel measurements methodology for investigation of a 3-axis free rotation model. This methods has been applied to the DREV-ISL reference model in order to compare coefficients obtained by this method with numerical results

Dimethyl sulfoxide enhances GLUT4 translocation through a reduction in GLUT4 endocytosis in insulin-stimulated 3T3-L1 adipocytes.

International audienceInsulin increases muscle and fat cell glucose uptake by inducing the translocation of glucose transporter GLUT4 from intracellular compartments to the plasma membrane. Here, we have demonstrated that in 3T3-L1 adipocytes, DMSO at concentrations higher than 7.5% augmented cell surface GLUT4 levels in the absence and presence of insulin, but that at lower concentrations, DMSO only enhanced GLUT4 levels in insulin-stimulated cells. At a 5% concentration, DMSO also increased cell surface levels of the transferrin receptor and GLUT1. Glucose uptake experiments indicated that while DMSO enhanced cell surface glucose transporter levels, it also inhibited glucose transporter activity. Our studies further demonstrated that DMSO did not sensitize the adipocytes for insulin and that its effect on GLUT4 was readily reversible (t1/2∼12 min) and maintained in insulin-resistant adipocytes. An enhancement of insulin-induced GLUT4 translocation was not observed in 3T3-L1 preadipocytes and L6 myotubes, indicating cell specificity. DMSO did not enhance insulin signaling nor exocytosis of GLUT4 vesicles, but inhibited GLUT4 internalization. While other chemical chaperones (glycerol and 4-phenyl butyric acid) also acutely enhanced insulin-induced GLUT4 translocation, these effects were not mediated via changes in GLUT4 endocytosis. We conclude that DMSO is the first molecule to be described that instantaneously enhances insulin-induced increases in cell surface GLUT4 levels in adipocytes, at least in part through a reduction in GLUT4 endocytosis

Dimethyl sulfoxide enhances GLUT4 translocation through a reduction in GLUT4 endocytosis in insulin-stimulated 3T3-L1 adipocytes.

International audienceInsulin increases muscle and fat cell glucose uptake by inducing the translocation of glucose transporter GLUT4 from intracellular compartments to the plasma membrane. Here, we have demonstrated that in 3T3-L1 adipocytes, DMSO at concentrations higher than 7.5% augmented cell surface GLUT4 levels in the absence and presence of insulin, but that at lower concentrations, DMSO only enhanced GLUT4 levels in insulin-stimulated cells. At a 5% concentration, DMSO also increased cell surface levels of the transferrin receptor and GLUT1. Glucose uptake experiments indicated that while DMSO enhanced cell surface glucose transporter levels, it also inhibited glucose transporter activity. Our studies further demonstrated that DMSO did not sensitize the adipocytes for insulin and that its effect on GLUT4 was readily reversible (t1/2∼12 min) and maintained in insulin-resistant adipocytes. An enhancement of insulin-induced GLUT4 translocation was not observed in 3T3-L1 preadipocytes and L6 myotubes, indicating cell specificity. DMSO did not enhance insulin signaling nor exocytosis of GLUT4 vesicles, but inhibited GLUT4 internalization. While other chemical chaperones (glycerol and 4-phenyl butyric acid) also acutely enhanced insulin-induced GLUT4 translocation, these effects were not mediated via changes in GLUT4 endocytosis. We conclude that DMSO is the first molecule to be described that instantaneously enhances insulin-induced increases in cell surface GLUT4 levels in adipocytes, at least in part through a reduction in GLUT4 endocytosis

Les salles de consommation de drogue à moindre risque

Une loi du 26 janvier 2016 a autorisé l’expérimentation de salles de consommation de drogues à moindre risque (SCMR). Le but est de réduire les risques liés aux pratiques des usagers de drogues, au niveau de l'usager comme de la collectivité, en termes de santé publique comme d’ordre public. Inédit en France et très controversé, le dispositif, prévu pour une durée maximale de six ans, donnera lieu à une double évaluation scientifique afin notamment d’en déterminer la pérennisation. C’est dans ce cadre nouveau que deux espaces de ce type ont d’ores et déjà été ouverts à Paris et Strasbourg à l’automne 2016. La France rejoint ainsi un mouvement international qui s’affirme progressivement, notamment dans plusieurs de nos voisins européens et au Canada. Cependant, cet approfondissement de la politique de réduction des risques en matière de drogues s’articule difficilement avec le modèle premier et dominant : le modèle prohibitionniste. Reposant notamment sur la liaison de la répression et de la médicalisation de la consommation de stupéfiants, celui-ci poursuit un objectif autrement radical : l’éradication des drogues. La controverse ne se réduit pas à la confrontation des SCMR au modèle prohibitionniste. Les débats procèdent également de l’ambivalence intrinsèque du dispositif considéré. Présenté comme pragmatique et humaniste, le dispositif est autrement complexe : il peut être lu comme l’avatar d’une approche gestionnaire des problèmes sociaux. Les SCMR posent donc des problèmes épineux que seule une approche pluridisciplinaire permet de poser. Parallèlement, elles sont au cœur de problématiques transversales qui les dépassent en même temps qu’elles les cristallisent. Les SCMR sont ainsi non seulement un objetde recherche mais encore un anglede recherche. Leur genèse retracée, ces deux logiques doivent être envisagées à plusieurs voix : suret parles SCMR. Faisant suite à un colloque pluridisciplinaire et international organisé dans cette perspective, à Rennes, les 7 et 8 novembre 2017, par l’UMR CNRS IODE, le présent dossier n’en est que l’écho partiel. Le choix a été fait de le concentrer sur les questions tenant aux principaux acteurs de la vie quotidienne d’une SCMR : intervenants en réduction des risques, usagers, riverains. Cette évocation est précédée de deux articles envisageant le dispositif de manière globale et suivie de trois contributions qui dépassent la seule question des SCMR pour, à partir d’elles, réfléchir à ce que peut vouloir dire (et faire), aujourd’hui, la notion d’autonomie