Polymer Nanocomposites Containing Functionalised Multiwalled Carbon NanoTubes: a Particular Attention to Polyolefin Based Materials

International audienc

Exposure to excessive heat and impacts on labour productivity linked to cumulative CO2 emissions

Cumulative CO2 emissions are a robust predictor of mean temperature increase. However, many societal impacts are driven by exposure to extreme weather conditions. Here, we show that cumulative emissions can be robustly linked to regional changes of a heat exposure indicator, as well as the resulting socioeconomic impacts associated with labour productivity loss in vulnerable economic sectors. We estimate historical and future increases in heat exposure using simulations from eight Earth System Models. Both the global intensity and spatial pattern of heat exposure evolve linearly with cumulative emissions across scenarios (1% CO2, RCP4.5 and RCP8.5). The pattern of heat exposure at a given level of global temperature increase is strongly affected by non-CO2 forcing. Global non-CO2 greenhouse gas emissions amplify heat exposure, while high local emissions of aerosols could moderate exposure. Considering CO2 forcing only, we commit ourselves to an additional annual loss of labour productivity of about 2% of total GDP per unit of trillion tonne of carbon emitted. This loss doubles when adding non-CO2 forcing of the RCP8.5 scenario. This represents an additional economic loss of about 4,400 G$every year (i.e. 0.59$/tCO2), varying across countries with generally higher impact in lower-income countries

Exposure to excessive heat and impacts on labour productivity linked to cumulative CO2 emissions

Cumulative CO2 emissions are a robust predictor of mean temperature increase. However, many societal impacts are driven by exposure to extreme weather conditions. Here, we show that cumulative emissions can be robustly linked to regional changes of a heat exposure indicator, as well as the resulting socioeconomic impacts associated with labour productivity loss in vulnerable economic sectors. We estimate historical and future increases in heat exposure using simulations from eight Earth System Models. Both the global intensity and spatial pattern of heat exposure evolve linearly with cumulative emissions across scenarios (1% CO2, RCP4.5 and RCP8.5). The pattern of heat exposure at a given level of global temperature increase is strongly affected by non-CO2 forcing. Global non-CO2 greenhouse gas emissions amplify heat exposure, while high local emissions of aerosols could moderate exposure. Considering CO2 forcing only, we commit ourselves to an additional annual loss of labour productivity of about 2% of total GDP per unit of trillion tonne of carbon emitted. This loss doubles when adding non-CO2 forcing of the RCP8.5 scenario. This represents an additional economic loss of about 4,400 G$every year (i.e. 0.59$/tCO2), varying across countries with generally higher impact in lower-income countries

Objective comparison of particle tracking methods

Particle tracking is of key importance for quantitative analysis of intracellular dynamic processes from time-lapse microscopy image data. Because manually detecting and following large numbers of individual particles is not feasible, automated computational methods have been developed for these tasks by many groups. Aiming to perform an objective comparison of methods, we gathered the community and organized an open competition in which participating teams applied their own methods independently to a commonly defined data set including diverse scenarios. Performance was assessed using commonly defined measures. Although no single method performed best across all scenarios, the results revealed clear differences between the various approaches, leading to notable practical conclusions for users and developers

The c.429_452 duplication of the ARX gene: a unique developmental-model of limb kinetic apraxia:

BACKGROUND: The c.429_452dup24 of the ARX gene is a rare genetic anomaly, leading to X-Linked Intellectual Disability without brain malformation. While in certain cases c.429_452dup24 has been associated with specific clinical patterns such as Partington syndrome, the consequence of this mutation has been also often classified as "non-specific Intellectual Disability". The present work aims at a more precise description of the clinical features linked to the c.429_452dup24 mutation. METHODS: We clinically reviewed all affected patients identified in France over a five-year period, i.e. 27 patients from 12 different families. Detailed cognitive, behavioural, and motor evaluation, as well as standardized videotaped assessments of oro-lingual and gestural praxis, were performed. In a sub-group of 13 ARX patients, kinematic and MRI studies were further accomplished to better characterize the motor impairment prevalent in the ARX patients group. To ensure that data were specific to the ARX gene mutation and did not result from low-cognitive functioning per se, a group of 27 age- and IQ-matched Down syndrome patients served as control. RESULTS: Neuropsychological and motor assessment indicated that the c.429_452dup24 mutation constitutes a recognizable clinical syndrome: ARX patients exhibiting Intellectual Disability, without primary motor impairment, but with a very specific upper limb distal motor apraxia associated with a pathognomonic hand-grip. Patients affected with the so-called Partington syndrome, which involves major hand dystonia and orolingual apraxia, exhibit the most severe symptoms of the disorder. The particular "reach and grip" impairment which was observed in all ARX patients, but not in Down syndrome patients, was further characterized by the kinematic data: (i) loss of preference for the index finger when gripping an object, (ii) major impairment of fourth finger deftness, and (iii) a lack of pronation movements. This lack of distal movement coordination exhibited by ARX patients is associated with the loss of independent digital dexterity and is similar to the distortion of individual finger movements and posture observed in Limb Kinetic Apraxia. CONCLUSION: These findings suggest that the ARX c.429_452dup24 mutation may be a developmental model for Limb Kinetic Apraxia

Une lettre inédite de Proudhon

Chaumont Jean-Philippe. Une lettre inédite de Proudhon. In: Revue d’histoire moderne et contemporaine, tome 38 N°4, Octobre-décembre 1991. pp. 649-657

Diffusion of the dicumyl peroxide in molten polymer probed by rheology

International audienceThe mutual coefficient of diffusion of the dicumyl peroxide (DCP), which diffuses into an ethylene-octene copolymer above its Tg was measured from an innovative rheological experiment. The experiments were carried out on a parallel plate geometry rheometer. The method is based on the cross-linking of a two-layer sample; the upper layer contains 2 wt% of DCP, and the lower layer is free of DCP. Actually, this experiment is based on the competition between the reaction of cross-linking and the diffusion of DCP in the lower layer. Comparing this rheological behavior with the rheological kinetic of cross-linking of an homogeneous sample with 1 wt% DCP, we are able, from an inverse fitting procedure, to calculate the mutual coefficient of diffusion. Our hypothesis is that the diffusion of DCP in the copolymer above Tg, can be described by Fick's classical law. Using Fick's law, the concentration of the DCP was established for any given point of the thickness of the two-layer sample at any time. Using a one-dimensional grid to solve continuous equations that describe the different rheological contributions of each abscissa, we determined the linear viscoelastic response of the whole sample. Comparing the experimental storage modulus of the two layer sample to the values measured from an homogeneous sample, we found the values of the mutual coefficient of diffusion. Finally, a simple relation, which describes the mutual coefficient of diffusion of DCP into melt ethylene-octene copolymer was established according to an Arrhenius law as: D12 = 1.25 x 102exp(-70.0 × 103 /RT)m2/s Moreover, this work clearly shows how a reaction in molten media can be controlled by the diffusion process of small reactive molecules

Étude modèle de la Polymérisation Radicalaire Contrôlée en surface (couches minces de Polystyrène à densité variable : structure et mobilité)

Ce travail consiste en l'étude fondamentale de la polymérisation radicalaire contrôlée (PRC) comme outil de création, modification et fonctionnalisation de surfaces et/ou interfaces. Le système modèle choisi permet une croissance des chaînes à partir de surfaces planes et macroscopiques de silice selon un processus de polymérisation radicalaire contrôlée par l'intermédiaire du TEMPO (terminaison réversible). L'étude de la PRC en surface a nécessité : - le choix d'une méthode (grafting from avec dépôt des amorceurs par la technique de Langmuir-Blodgett réactif) - la mise en place d'un système adéquat (synthèse d'amorceurs bifonctionnels, protocole de polymérisation, caractérisations adaptées aux surfaces et couches minces) permettant d'apprécier l'influence du confinement sur la polymérisation en surface. L'identification du rôle des paramètres influençant la polymérisation et la vérification de son caractère contrôlé ont été menées en parallèle. L'élaboration de films à densité variable et contrôlée a montré que l'étape de greffage des amorceurs est cruciale quant à l'évolution des propriétés. Des couches minces de polystyrène peuvent être formées avec un certain degré d'organisation et un haut taux d'étirement des chaînes "à sec" (réflectivité de neutrons, diffraction des RX). Parmi les diverses propriétés spécifiques des chaînes à l'interface, la mobilité a été évaluée au travers de mesures de Tg, température dépendant en premier lieu de l'épaisseur du film et des caractéristiques propres au polymère considéré. La structure et l'arrangement des chaînes, facteurs contrôlés par la méthode de préparation, semblent susceptibles d'affecter la mobilité à l'interface. Les résultats sont discutés aux vues des controverses actuelles sur l'origine des phénomènes de mobilité dans les films minces. Enfin, le potentiel de cette technique de greffage de polymères "vivants" est illustré par la fonctionnalisation des pointes AFM (sondes de surface).LYON1-BU.Sciences (692662101) / SudocSudocFranceF