24 research outputs found
Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches
Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly
The Gender-Climate Change Nexus â A critical study of a gender-transformative approach to the international climate change regime
This thesis aims to shed some light on the gender-climate change nexus. Indeed, climate governance might appear gender-neutral, but climate changes impacts aggravate existing gender inequalities. Because of this, gender and womenâs considerations have been first ignored, and once they were taken into account, they were misunderstood. Therefore, the full and meaningful integration of gender and womenâs considerations when addressing climate change concerns is critical for achieving climate justice and gender equality as it would provide for gender-transformative climate action. This paper explores the incorporation of such considerations within the climate regime and the role of feminist advocacy in this evolution. It is observed that the climate regime largely aims at a gender-responsive content but it is not achieved in practice in all areas of climate action. From this foundation, this paper then argues that the overarching strategy of gender mainstreaming, widespread within the climate regime, might not be sufficient to achieve gender-transformative climate governance. The adoption of a rights-based approach to climate governance, as a catalyst for systemic change, is then suggested in order to achieve a gender-transformative climate change regime
Fragilisation du poly(butylene terephthalate) induite par injection
This work deals with PBT embrittlement mechanisms during injection molding processing causing epidemic breakage (ppm order) that part producer have to face up with. We started this work by studying the influence of âbarrel temperature/residence timeâ couple on normalized dumbÂbell samples mechanical properties. Hence we were able to establish a timeÂtemperature diagram that can be used by manufacturers to optimize the process.The dumbÂbell samples analysis showed that embrittlement is caused by the used of high temperature leading to average molar mass decrease. We extended this structuralÂproperties study to other PBT grades and several ageing (hydrolysis and thermoÂoxidation) and established an âembrittlement mapâ crystallinity in function of weight molar mass defining ductile/brittle transition frontier essential in mechanical properties study. In a second part, we decided to study degradation at molecular scale. A complete kinetic model successfully described and highlighted that thermolytic decomposition occurring at that the same time scale as injection process. This aspect is fundamental since PBT injection commercial grades have moderated weight molar mass so that only a few chain breaking leads to complete part property loss. A parallel study on oxidation phenomena suggest that they only play a minor role during injection process but can be predominant during part life. That is why stabilizers can be very useful and must be added to polymer formulation, before processing. Finally, even if PBT is surely moderately hydrophilic, but its hydrolysis reactions can be very fast and catalyzed by carboxylic acid (formed by hydrolysis and present at chain ends). For injection processing, it is mandatory to perfectly dry the PBT pellets but also the masterbatch, since pigments appear to have a negative impact on hydrolysis stability.Cette thĂšse porte sur la comprĂ©hension des mĂ©canismes conduisant Ă la dĂ©gradation de piĂšces PBT se produisant au cours de leur mise en Ćuvre par injection, afin dâexpliquer des phĂ©nomĂšnes Ă©pidĂ©miques de casse (de lâordre de la dizaine de ppm) auxquels peut faire face des transformateurs de matiĂšre. Nous avons commencĂ© par Ă©tudier lâeffet du couple « tempĂ©rature de fourreau/temps de sĂ©jour » sur les propriĂ©tĂ©s mĂ©caniques dâĂ©prouvettes normalisĂ©es, ce qui nous a permis de mettre au point un premier diagramme « temps â tempĂ©rature » dont le but est de permettre au transformateur dâoptimiser la mise en Ćuvre. Le phĂ©nomĂšne de fragilisation a en premier lieu Ă©tĂ© expliquĂ© par la dĂ©gradation thermique de la matiĂšre, conduisant Ă des coupures de chaines et une rĂ©duction de la masse molaire moyenne des chaines. En gĂ©nĂ©ralisant ces Ă©tudes structure-propriĂ©tĂ©s Ă dâautres Ă©chantillons (obtenus Ă partir de diffĂ©rents grades de PBT) pour diffĂ©rents modes de vieillissement (hydrolytique, thermoÂoxydant..), nous sommes parvenus Ă proposer une carte de fragilisation «masse molaire / taux de cristallinitĂ© » qui permet de prĂ©dire le seuil dâendommagement nĂ©cessaire Ă la perte de propriĂ©tĂ©s mĂ©caniques. Nous nous sommes ensuite focalisĂ©s sur les mĂ©canismes « molĂ©culaires » Ă lâorigine de cette dĂ©gradation. Un modĂšle cinĂ©tique complet a Ă©tĂ© proposĂ© et dĂ©crit avec succĂšs la dĂ©composition thermolytique des motifs, qui semble avoir lieu dans une Ă©chelle de temps comparable au procĂ©dĂ©, et dont lâeffet est dâautant plus marquĂ© que les grades destinĂ©s Ă lâinjection sont constituĂ©s de chaines de masse molaire modĂ©rĂ©es ne tolĂ©rant quâun faible nombre de coupures de chaines sous peine de conduire Ă la ruine du matĂ©riau. Une Ă©tude prĂ©liminaire des phĂ©nomĂšnes dâoxydation suggĂšre quâils ne jouent quâun rĂŽle mineur dans le procĂ©dĂ©, mais quâils peuvent en revanche prĂ©dominer dans les conditions dâutilisation du matĂ©riau, oĂč une stabilisation adĂ©quate doit ĂȘtre dĂ©veloppĂ©e. Enfin, une derniĂšre complexitĂ© provient du fait que le PBT, mĂȘme sâil nâest que modĂ©rĂ©ment hydrophile, subit des phĂ©nomĂšnes dâhydrolyse assez rapides et catalysĂ©s par les acides carboxyliques (issus des rĂ©actions dâhydrolyse, ou prĂ©sents en bouts de chaines). La maitrise du procĂ©dĂ© dâinjection requiert donc un sĂ©chage strict de la matiĂšre mais Ă©galement des mĂ©langes maitres nĂ©cessaires Ă teinter la matiĂšre, ceuxÂci Ă©tant plus fortement hygroscopiques, et les pigments semblant avoir une influence nĂ©faste sur la tenue Ă lâhydrolyse
Fragilisation du poly(butylene terephthalate) induite par injection
This work deals with PBT embrittlement mechanisms during injection molding processing causing epidemic breakage (ppm order) that part producer have to face up with. We started this work by studying the influence of âbarrel temperature/residence timeâ couple on normalized dumb-bell samples mechanical properties. Hence we were able to establish a time-temperature diagram that can be used by manufacturers to optimize the process. The dumb-bell samples analysis showed that embrittlement is caused by the used of high temperature leading to average molar mass decrease. We extended this structural-properties study to other PBT grades and several ageing (hydrolysis and thermo-oxidation) and established an âembrittlement mapâ crystallinity in function of weight molar mass defining ductile/brittle transition frontier essential in mechanical properties study. In a second part, we decided to study degradation at molecular scale. A complete kinetic model successfully described and highlighted that thermolytic decomposition occurring at that the same time scale as injection process. This aspect is fundamental since PBT injection commercial grades have moderated weight molar mass so that only a few chain breaking leads to complete part property loss. A parallel study on oxidation phenomena suggest that they only play a minor role during injection process but can be predominant during part life. That is why stabilizers can be very useful and must be added to polymer formulation, before processing.Finally, even if PBT is surely moderately hydrophilic, but its hydrolysis reactions can be very fast and catalyzed by carboxylic acid (formed by hydrolysis and present at chain ends). For injection processing, it is mandatory to perfectly dry the PBT pellets but also the masterbatch, since pigments appear to have a negative impact on hydrolysis stability.Cette thĂšse porte sur la comprĂ©hension des mĂ©canismes conduisant Ă la dĂ©gradation de piĂšces PBT se produisant au cours de leur mise en Ćuvre par injection, afin dâexpliquer des phĂ©nomĂšnes Ă©pidĂ©miques de casse (de lâordre de la dizaine de ppm) auxquels peut faire face des transformateurs de matiĂšre. Nous avons commencĂ© par Ă©tudier lâeffet du couple « tempĂ©rature de fourreau/temps de sĂ©jour » sur les propriĂ©tĂ©s mĂ©caniques dâĂ©prouvettes normalisĂ©es, ce qui nous a permis de mettre au point un premier diagramme « temps â tempĂ©rature » dont le but est de permettre au transformateur dâoptimiser la mise en Ćuvre. Le phĂ©nomĂšne de fragilisation a en premier lieu Ă©tĂ© expliquĂ© par la dĂ©gradation thermique de la matiĂšre, conduisant Ă des coupures de chaines et une rĂ©duction de la masse molaire moyenne des chaines. En gĂ©nĂ©ralisant ces Ă©tudes structure-propriĂ©tĂ©s Ă dâautres Ă©chantillons (obtenus Ă partir de diffĂ©rents grades de PBT) pour diffĂ©rents modes de vieillissement (hydrolytique, thermo-oxydant..), nous sommes parvenus Ă proposer une carte de fragilisation « masse molaire / taux de cristallinitĂ© » qui permet de prĂ©dire le seuil dâendommagement nĂ©cessaire Ă la perte de propriĂ©tĂ©s mĂ©caniques. Nous nous sommes ensuite focalisĂ©s sur les mĂ©canismes « molĂ©culaires » Ă lâorigine de cette dĂ©gradation. Un modĂšle cinĂ©tique complet a Ă©tĂ© proposĂ© et dĂ©crit avec succĂšs la dĂ©composition thermolytique des motifs, qui semble avoir lieu dans une Ă©chelle de temps comparable au procĂ©dĂ©, et dont lâeffet est dâautant plus marquĂ© que les grades destinĂ©s Ă lâinjection sont constituĂ©s de chaines de masse molaire modĂ©rĂ©es ne tolĂ©rant quâun faible nombre de coupures de chaines sous peine de conduire Ă la ruine du matĂ©riau. Une Ă©tude prĂ©liminaire des phĂ©nomĂšnes dâoxydation suggĂšre quâils ne jouent quâun rĂŽle mineur dans le procĂ©dĂ©, mais quâils peuvent en revanche prĂ©dominer dans les conditions dâutilisation du matĂ©riau, oĂč une stabilisation adĂ©quate doit ĂȘtre dĂ©veloppĂ©e. Enfin, une derniĂšre complexitĂ© provient du fait que le PBT, mĂȘme sâil nâest que modĂ©rĂ©ment hydrophile, subit des phĂ©nomĂšnes dâhydrolyse assez rapides et catalysĂ©s par les acides carboxyliques (issus des rĂ©actions dâhydrolyse, ou prĂ©sents en bouts de chaines). La maitrise du procĂ©dĂ© dâinjection requiert donc un sĂ©chage strict de la matiĂšre mais Ă©galement des mĂ©langes maitres nĂ©cessaires Ă teinter la matiĂšre, ceux-ci Ă©tant plus fortement hygroscopiques, et les pigments semblant avoir une influence nĂ©faste sur la tenue Ă lâhydrolyse
Poly(butylene terephthalate) embrittlement induced by injection
Cette thĂšse porte sur la comprĂ©hension des mĂ©canismes conduisant Ă la dĂ©gradation de piĂšces PBT se produisant au cours de leur mise en Ćuvre par injection, afin dâexpliquer des phĂ©nomĂšnes Ă©pidĂ©miques de casse (de lâordre de la dizaine de ppm) auxquels peut faire face des transformateurs de matiĂšre. Nous avons commencĂ© par Ă©tudier lâeffet du couple « tempĂ©rature de fourreau/temps de sĂ©jour » sur les propriĂ©tĂ©s mĂ©caniques dâĂ©prouvettes normalisĂ©es, ce qui nous a permis de mettre au point un premier diagramme « temps â tempĂ©rature » dont le but est de permettre au transformateur dâoptimiser la mise en Ćuvre. Le phĂ©nomĂšne de fragilisation a en premier lieu Ă©tĂ© expliquĂ© par la dĂ©gradation thermique de la matiĂšre, conduisant Ă des coupures de chaines et une rĂ©duction de la masse molaire moyenne des chaines. En gĂ©nĂ©ralisant ces Ă©tudes structure-propriĂ©tĂ©s Ă dâautres Ă©chantillons (obtenus Ă partir de diffĂ©rents grades de PBT) pour diffĂ©rents modes de vieillissement (hydrolytique, thermo-oxydant..), nous sommes parvenus Ă proposer une carte de fragilisation « masse molaire / taux de cristallinitĂ© » qui permet de prĂ©dire le seuil dâendommagement nĂ©cessaire Ă la perte de propriĂ©tĂ©s mĂ©caniques. Nous nous sommes ensuite focalisĂ©s sur les mĂ©canismes « molĂ©culaires » Ă lâorigine de cette dĂ©gradation. Un modĂšle cinĂ©tique complet a Ă©tĂ© proposĂ© et dĂ©crit avec succĂšs la dĂ©composition thermolytique des motifs, qui semble avoir lieu dans une Ă©chelle de temps comparable au procĂ©dĂ©, et dont lâeffet est dâautant plus marquĂ© que les grades destinĂ©s Ă lâinjection sont constituĂ©s de chaines de masse molaire modĂ©rĂ©es ne tolĂ©rant quâun faible nombre de coupures de chaines sous peine de conduire Ă la ruine du matĂ©riau. Une Ă©tude prĂ©liminaire des phĂ©nomĂšnes dâoxydation suggĂšre quâils ne jouent quâun rĂŽle mineur dans le procĂ©dĂ©, mais quâils peuvent en revanche prĂ©dominer dans les conditions dâutilisation du matĂ©riau, oĂč une stabilisation adĂ©quate doit ĂȘtre dĂ©veloppĂ©e. Enfin, une derniĂšre complexitĂ© provient du fait que le PBT, mĂȘme sâil nâest que modĂ©rĂ©ment hydrophile, subit des phĂ©nomĂšnes dâhydrolyse assez rapides et catalysĂ©s par les acides carboxyliques (issus des rĂ©actions dâhydrolyse, ou prĂ©sents en bouts de chaines). La maitrise du procĂ©dĂ© dâinjection requiert donc un sĂ©chage strict de la matiĂšre mais Ă©galement des mĂ©langes maitres nĂ©cessaires Ă teinter la matiĂšre, ceux-ci Ă©tant plus fortement hygroscopiques, et les pigments semblant avoir une influence nĂ©faste sur la tenue Ă lâhydrolyse.This work deals with PBT embrittlement mechanisms during injection molding processing causing epidemic breakage (ppm order) that part producer have to face up with. We started this work by studying the influence of âbarrel temperature/residence timeâ couple on normalized dumb-bell samples mechanical properties. Hence we were able to establish a time-temperature diagram that can be used by manufacturers to optimize the process. The dumb-bell samples analysis showed that embrittlement is caused by the used of high temperature leading to average molar mass decrease. We extended this structural-properties study to other PBT grades and several ageing (hydrolysis and thermo-oxidation) and established an âembrittlement mapâ crystallinity in function of weight molar mass defining ductile/brittle transition frontier essential in mechanical properties study. In a second part, we decided to study degradation at molecular scale. A complete kinetic model successfully described and highlighted that thermolytic decomposition occurring at that the same time scale as injection process. This aspect is fundamental since PBT injection commercial grades have moderated weight molar mass so that only a few chain breaking leads to complete part property loss. A parallel study on oxidation phenomena suggest that they only play a minor role during injection process but can be predominant during part life. That is why stabilizers can be very useful and must be added to polymer formulation, before processing.Finally, even if PBT is surely moderately hydrophilic, but its hydrolysis reactions can be very fast and catalyzed by carboxylic acid (formed by hydrolysis and present at chain ends). For injection processing, it is mandatory to perfectly dry the PBT pellets but also the masterbatch, since pigments appear to have a negative impact on hydrolysis stability
Fragilisation du poly(butylene terephthalate) induite par injection
This work deals with PBT embrittlement mechanisms during injection molding processing causing epidemic breakage (ppm order) that part producer have to face up with. We started this work by studying the influence of âbarrel temperature/residence timeâ couple on normalized dumb-bell samples mechanical properties. Hence we were able to establish a time-temperature diagram that can be used by manufacturers to optimize the process. The dumb-bell samples analysis showed that embrittlement is caused by the used of high temperature leading to average molar mass decrease. We extended this structural-properties study to other PBT grades and several ageing (hydrolysis and thermo-oxidation) and established an âembrittlement mapâ crystallinity in function of weight molar mass defining ductile/brittle transition frontier essential in mechanical properties study. In a second part, we decided to study degradation at molecular scale. A complete kinetic model successfully described and highlighted that thermolytic decomposition occurring at that the same time scale as injection process. This aspect is fundamental since PBT injection commercial grades have moderated weight molar mass so that only a few chain breaking leads to complete part property loss. A parallel study on oxidation phenomena suggest that they only play a minor role during injection process but can be predominant during part life. That is why stabilizers can be very useful and must be added to polymer formulation, before processing.Finally, even if PBT is surely moderately hydrophilic, but its hydrolysis reactions can be very fast and catalyzed by carboxylic acid (formed by hydrolysis and present at chain ends). For injection processing, it is mandatory to perfectly dry the PBT pellets but also the masterbatch, since pigments appear to have a negative impact on hydrolysis stability.Cette thĂšse porte sur la comprĂ©hension des mĂ©canismes conduisant Ă la dĂ©gradation de piĂšces PBT se produisant au cours de leur mise en Ćuvre par injection, afin dâexpliquer des phĂ©nomĂšnes Ă©pidĂ©miques de casse (de lâordre de la dizaine de ppm) auxquels peut faire face des transformateurs de matiĂšre. Nous avons commencĂ© par Ă©tudier lâeffet du couple « tempĂ©rature de fourreau/temps de sĂ©jour » sur les propriĂ©tĂ©s mĂ©caniques dâĂ©prouvettes normalisĂ©es, ce qui nous a permis de mettre au point un premier diagramme « temps â tempĂ©rature » dont le but est de permettre au transformateur dâoptimiser la mise en Ćuvre. Le phĂ©nomĂšne de fragilisation a en premier lieu Ă©tĂ© expliquĂ© par la dĂ©gradation thermique de la matiĂšre, conduisant Ă des coupures de chaines et une rĂ©duction de la masse molaire moyenne des chaines. En gĂ©nĂ©ralisant ces Ă©tudes structure-propriĂ©tĂ©s Ă dâautres Ă©chantillons (obtenus Ă partir de diffĂ©rents grades de PBT) pour diffĂ©rents modes de vieillissement (hydrolytique, thermo-oxydant..), nous sommes parvenus Ă proposer une carte de fragilisation « masse molaire / taux de cristallinitĂ© » qui permet de prĂ©dire le seuil dâendommagement nĂ©cessaire Ă la perte de propriĂ©tĂ©s mĂ©caniques. Nous nous sommes ensuite focalisĂ©s sur les mĂ©canismes « molĂ©culaires » Ă lâorigine de cette dĂ©gradation. Un modĂšle cinĂ©tique complet a Ă©tĂ© proposĂ© et dĂ©crit avec succĂšs la dĂ©composition thermolytique des motifs, qui semble avoir lieu dans une Ă©chelle de temps comparable au procĂ©dĂ©, et dont lâeffet est dâautant plus marquĂ© que les grades destinĂ©s Ă lâinjection sont constituĂ©s de chaines de masse molaire modĂ©rĂ©es ne tolĂ©rant quâun faible nombre de coupures de chaines sous peine de conduire Ă la ruine du matĂ©riau. Une Ă©tude prĂ©liminaire des phĂ©nomĂšnes dâoxydation suggĂšre quâils ne jouent quâun rĂŽle mineur dans le procĂ©dĂ©, mais quâils peuvent en revanche prĂ©dominer dans les conditions dâutilisation du matĂ©riau, oĂč une stabilisation adĂ©quate doit ĂȘtre dĂ©veloppĂ©e. Enfin, une derniĂšre complexitĂ© provient du fait que le PBT, mĂȘme sâil nâest que modĂ©rĂ©ment hydrophile, subit des phĂ©nomĂšnes dâhydrolyse assez rapides et catalysĂ©s par les acides carboxyliques (issus des rĂ©actions dâhydrolyse, ou prĂ©sents en bouts de chaines). La maitrise du procĂ©dĂ© dâinjection requiert donc un sĂ©chage strict de la matiĂšre mais Ă©galement des mĂ©langes maitres nĂ©cessaires Ă teinter la matiĂšre, ceux-ci Ă©tant plus fortement hygroscopiques, et les pigments semblant avoir une influence nĂ©faste sur la tenue Ă lâhydrolyse
Impact of intragranular misorientation on void swelling and inter-granular cavities after ion irradiation in standard and additive manufacturing 316 L austenitic steels
International audienceAdditive manufacturing (AM) is a promising technology for the design of materials with complex geometries with reduced cost and material waste. In order to be used in the nuclear industry, the capability of AM materials, in term of radiation resistance must be compared with materials elaborated in conventional ways. In this work, the radiation resistance of 316L austenitic stainless steels (ASSs) elaborated by AM is compared to a solution-annealed 316L ASS after irradiation with 5 MeV Fe for 3 dpa at 550 °C (873 K). After irradiation, cavities are mainly located near grain boundaries for all studied alloys. Intra-granular cavities are only found in the AM material after heat treatment and are likely to be remaining porosity already present before irradiation. No cavities in intra-granular position are found in the conventional 316L ASS or in the AM material after hot isostatic pressing (HIP) at 1100 °C. It suggests that the void swelling ASSs starts by the formation of cavities at grain boundaries followed by a formation of cavities in intra-granular position, conventionally studied. Loops in the AM material with a hot treatment at 700°C are heterogeneously distributed due to a bimodal distribution of grains in terms of intra-granular misorientation. The intra-granular misorientation drastically reduces the loop density after irradiation. Frank and perfect loops are found to be only interstitial-type loops. The larger cavities' size and the more advanced dislocations network in the AM HIP sample suggests a slightly reduced radiation swelling resistance for the AM material but further investigations at higher irradiation dose have to be done
Impact cognitif dâune chirurgie programmĂ©e du membre infĂ©rieur chez les patients de plus de 60 ans
Caffeine intake increases plasma ketones: an acute metabolic study in humans
Brain glucose uptake declines during aging and is significantly impaired in AlzheimerĂą s disease. Ketones are the main alternative brain fuel to glucose so they represent a potential approach to compensate for the brain glucose reduction. Caffeine is of interest as a potential ketogenic agent owing to its actions on lipolysis/ lipid oxidation but whether it is ketogenic in humans is unknown. This study aimed to evaluate the acute ketogenic effect of two doses of caffeine in healthy adults (2.5; 5.0 mg/kg) during a 4-hour metabolic study period. Caffeine given at breakfast significantly stimulated ketone production in a dose-dependent manner (+88%; +116%) and also raised plasma free fatty acids. Whether caffeine has long-term ketogenic effects or could enhance the ketogenic effect of medium chain triglycerides remains to be determined. NCT 02694601The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author