Formation diplomante en métrologie des salles propres

L’utilisation des salles propres pour fabriquer des produits ou intervenir sur des patients estencadrée par les normes EN ISO 14644 et 14698. Cette technologie laisse une place importante à la métrologie,moyen essentiel pour s’assurer que l’installation et tous ses composants fonctionnent correctement.En France, l’ASPEC est l’Association nationale qui regroupe les personnes intéressées par ces salles. Membrede l’ICCCS (International Confederation of Contamination Control Societies) et de sa filiale l’ICEB (International Cleanroom Education Board) dont l’objectif à terme est d’avoir les mêmes programmes de formationdans tous les pays, l’ASPEC a mis en place une formation diplômante en métrologie des salles propres. Cellecipermet de former des intervenants capables de faire un examen métrologique de ces salles depuis le cahierdes charges jusqu’au compte-rendu final. 9 paramètres parmi les 14 recensés dans l’EN ISO 14644-3 y sontétudiés

Low-field magnetoresistance in La<inf>0.7</inf>Ca<inf>0.3</inf>MnO <inf>3</inf> manganite compounds prepared by the spray drying technique

Calcium-substituted lanthanum manganite compounds were synthesized by the spray drying technique. This method - whose main advantages are versatility, high reproducibility and scalability - yields small grain materials of high homogeneity and displaying low-field magnetoresistance effects. We report about the physical and chemical characterizations of these samples in order to investigate the potential interest of spray drying for the production of materials for low-field magnetoresistance applications. We have studied the dependence of the low-field magnetoresistance on the temperature and duration of the thermal treatment applied to the pelletized powders. The issue of the shape anisotropy (demagnetisation effects) influence on the magnetoresistance properties has also been dealt with. © 2005 Springer Science + Business Media, Inc

Preparation of BaZrO3 powders by a spray-drying process

The potential use of barium zirconate for the manufacture of corrosion-resistant substrates emphasizes the need for a simple, inexpensive, and easily scalable process to produce high-quality powders with well-controlled composition and properties. However, the classical solid-state preparation of barium zirconate leads to an inhomogeneous powder unsuitable for applications in highly corrosive environment. For this paper, the possibility to use the spray-drying technique for the preparation of BaZrO3 powders with a controlled size distribution and morphology was investigated. The influence of the nature and concentration of the precursor solution and the influence of the spray-drying step are discussed on the basis of x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and dilatometric measurements

Synergism between hypotonically induced calcium release and fatty acyl-CoA esters induced calcium release from intracellular stores

The non-mitochondrial Ca2+ stores in permeabilized A7r5 cells responded to a decrease in Mg-ATP concentration with a pronounced Ca2+ release if 20 mu M CoA was present. This release was rather specific for the preincubation or removal of ATP. ATP gamma S was much less effective and AMP-PNP, GTP, ITP, CTP, UTP, ADP, AMP, adenosine and adenine had no effect. CoA activated with an EC50 of 6 mu M. Dephospho-CoA was a less effective cofactor and desulfo-CoA was ineffective. The release induced by Mg-ATP removal did not occur in the presence of 2% fatty acid-free bovine serum albumin and did not develop at 4 degrees C. All these findings suggest that CoA had to be acylated by endogenous fatty-acyl-CoA synthetase to become effective. Myristoyl-and palmitoyl-CoA esters were identified as the most effective cofactors for the release. Ca2+ release induced by removing Mg-ATP did not occur if the osmolality of the medium was kept constant by addition of mannitol, sucrose, KCl, MgCl2 or Mg-GTP, indicating that the decrease in tonicity was the trigger for the release. Mg-ATP plus CoA also synergized with Ca2+ release induced by a hypotonic shock imposed by diluting the medium with H2O. Osmolality changes induced by decreasing the Mg-ATP concentration were more effective in releasing Ca2+ than equal decreases in concentration of all solutes. We conclude that fatty acyl-CoA esters sensitize the hypotonically induced Ca2+ release from the non-mitochondrial Ca2+ stores

Graph Partitioning Algorithms With Applications To Scientific Computing

Identifying the parallelism in a problem by partitioning its data and tasks among the processors of a parallel computer is a fundamental issue in parallel computing. This problem can be modeled as a graph partitioning problem in which the vertices of a graph are divided into a specified number of subsets such that few edges join two vertices in different subsets. Several new graph partitioning algorithms have been developed in the past few years, and we survey some of this activity. We describe the terminology associated with graph partitioning, the complexity of computing good separators, and graphs that have good separators. We then discuss early algorithms for graph partitioning, followed by three new algorithms based on geometric, algebraic, and multilevel ideas. The algebraic algorithm relies on an eigenvector of a Laplacian matrix associated with the graph to compute the partition. The algebraic algorithm is justified by formulating graph partitioning as a quadratic assignment p..

Autophagic Cell Death in Dictyostelium Requires the Receptor Histidine Kinase DhkM

Through random mutagenesis, the receptor histidine kinase DhkM was found essential for autophagic cell death (ACD) in Dictyostelium. DhkM is the most downstream known molecule required for this model ACD. Different DhkM mutants showed distinct non-vacuolizing ACD phenotypes and genetically separated previously undissociated late cell death events