The effect of shear stress reduction on endothelial cells : a microfluidic study of the actin cytoskeleton

Reduced blood flow, as occurring in ischemia or resulting from exposure to microgravity such as encountered in space flights, induces a decrease in the level of shear stress sensed by endothelial cells forming the inner part of blood vessels. In the present study, we use a microvasculature-on-a-chip device in order to investigate in vitro the effect of such a reduction in shear stress on shear-adapted endothelial cells. We find that, within 1 h of exposition to reduced wall shear stress, human umbilical vein endothelial cells undergo reorganization of their actin skeleton with a decrease in the number of stress fibers and actin being recruited into the cells' peripheral band, indicating a fairly fast change in the cells' phenotype due to altered flow

COCACOM : environnement de développement d'applications coopérantes et multimédia

This papers présent the COCACOM library : a set of class to distribute of multimédia applications design. The COCACOM class provide a gênerai platform of development and exploitation ensuring the distribution and communication between the set of applications in distributed architecture. This library contains fïve class to cover the following topics: parallelism, multimedia, graphic interface, reflex and coopératif work. Two COCACOM applications are presented in this paper: a visionar of burst document and a vote coopératif System

Etch mechanisms of low dielectric constant materials in high density plasmas

International audienc

Crystal structure determination of two pyridine derivatives: 4-[(E)-2-(4-methoxyphenyl)ethenyl]-1-methylpyridin-1-ium hexafluoro-λ6-phosphane and 4-[(E)-2-[4-(dimethylamino)phenyl]ethenyl]-1-phenyl-1λ5-pyridin-1-ylium hexafluoro-λ6-phosphane

The title molecular salts, C16H16NO+·PF6−, (I), and C21H21N2+·PF6−, (II), are pyridine derivatives. In compound (I), the cation comprises a methyl N-substituted pyridine ring and a methoxy-substituted benzene ring connected by a C=C double bond. The F atoms of the PF6− anion are disordered over two sets of sites with refined occupancy factors of 0.614 (7):0.386 (7). In compound (II), the cation comprises a pyridine ring attached to unsubstituted phenyl ring and a dimethylaniline ring, which are connected by a C=C double bond. The anion is PF6−. In both salts, the cation adopts an E configuration with respect to the C=C bond. The pyridine ring makes a dihedral angle of 9.86 (12)° with the methoxy-substituted benzene ring in compound (I) and 11.2 (3)° with the dimethylamine-substituted benzene ring in compound (II). In compound (I), the crystal packing is stabilized by weak C—H...F intermolecular interactions which result in R43(14) ring motifs, forming molecular sheets running parallel to (\overline{1}03). These are further stabilized by weak P—F...π interactions. In compound (II), the crystal packing is stabilized by C—H...F interactions, which result in R66(40) ring motifs, forming molecular sheets running parallel to (101) and these are further connected by π–π interactions

Modélisation du martelage à haute fréquence des assemblages soudés

Les joints soudés présentent bien souvent une durée de vie en fatigue relativement faible comparée à celle des matériaux de base et d’apport qui les composent. Plusieurs techniques d’amélioration post-soudage ont par conséquent été proposées et mises en œuvre dans ce domaine dont le martelage à haute fréquence ou « MHF ». Ce dernier constitue l’un des procédés les plus prometteurs de par son influence significative sur la tenue en fatigue de ce type d’assemblages. Toutefois, il est encore délicat de pouvoir prédire la durée de vie en fatigue des joints soudés traités par MHF. Nous proposons ici une démarche pour l’estimation de la durée de vie des assemblages traités par MHF. Cette démarche est en cours de validation mais permet d’ores et déjà d’identifier l’influence relative des principaux paramètres du traitement

Fluid description of Weibel-type instabilities via full pressure tensor dynamics

We discuss a fluid model for the description of Weibel-type instabilties based on the inclusion of the full pressure tensor dynamics. The linear analysis first performed by Bas

Microanalyse et hydrothermalisme oceanique. Premiers resultats et perspectives dans le domaine de la biologie

Specimens of hydrothermal vent organisms, Alvinella caudata and Bathymodiolus thermophilus were collected in 1982 from 13 degree N and 103 degree W, on the East Pacific Rise at a depth of 2600 m. The elemental composition was determined for some of their soft tissues at the structural and ultrastructural levels. Two microanalytical methods were used: secondary ion mass spectrometry and X-ray spectrometry. As examples, external and digestive epithelium and lumen of the digestive tract of Alvinella caudata and the gill and digestive gland of Bathymodiolus thermophilus were investigated. Intracellular localization of the elements, performed by electron microscopy, showed that spherocrystals and lysosomes were the target organelles of metal concentration. Moreover, bacteria were shown to be capable of elemental concentration. The correlations between the metal concentrations within the vent organisms and the metal concentrations characteristic of the vent environment are examined

Process optimization of a negative-tone CVD photoresist for 193 nm lithography applications

International audienc