New Disturbing Trend in Antimicrobial Resistance of Gram-Negative Pathogens

ope

Analyse morphologique de films CrN. Corrélation entre contrainte résiduelle et résistivité de films de chrome

Les films minces de nitrure de chrome ont sensiblement attiré l'attention, ces dernières années. Attrait du à leurs excellentes propriétés physiques, chimiques et mécaniques. Une partie de cette étude a porté sur la caractérisation morphologique de couches minces dures de nitrure de chrome (Cr-N), élaborées par PVD sur substrats de silicium (100) par pulvérisation magnétron. Nous avons considéré l'influence de la température de recuit sur l'adhérence et la stabilité thermique de ces films. Nous avons procédé à des caractérisations en microscopie électronique à balayage (MEB) équipé en microanalyse X (EDX).Des recuits d'une heure, entre 600°C et 1000°C sous azote N2, effectués sur des revêtements CrN,de différentes épaisseurs entre 0.5 et 1µm, ont montré la stabilité thermique de ces revêtements aux basses températures. Les résultats obtenus en MEB et EDX sont comparés aux résultats en DRX. Cette étude porte aussi sur des dépôts de couches de chrome élaborés par pulvérisation RF cathodique (PVD). L'analyse des contraintes résiduelles par le dispositif des anneaux de Newton, pour différentes épaisseurs, montre l'existence d'un pic de contraintes entre 170 et 200 nm. La méthode des quatre pointes a été utilisée pour déterminer la résistivité des couches de chrome. La résistivité décroît fortement pour les petites épaisseurs (< 100nm), pour ensuite se stabiliser à une valeur moyenne de 30µ.Ohm.cm. Une corrélation entre l'évolution des contraintes et de la résistivité nous a permis de faire un essai d'interprétation sur la croissance des films

Effect of substrate-target distance and sputtering pressure in the synthesis of AlN thin films

In this work, we analyze the influence of the processing pressure and the substrate–target distance on the synthesis by reactive sputtering of c-axis oriented polycrystalline aluminum nitride thin films deposited on Si(100) wafers. The crystalline quality of AlN has been characterized by high-resolution X-ray diffraction (HR-XRD). The films exhibited a very high degree of c-axis orientation especially when a low process pressure was used. After growth, residual stress measurements obtained indirectly from radius of curvature measurements of the wafer prior and after deposition are also provided. Two different techniques are used to determine the curvature—an optically levered laser beam and a method based on X-ray diffraction. There is a transition from compressive to tensile stress at a processing pressure around 2 mTorr. The transition occurs at different pressures for thin films of different thickness. The degree of c-axis orientation was not affected by the target–substrate distance as it was varied in between 30 and 70 mm

A recurrent mitochondrial p.Trp22Arg NDUFB3 variant causes a distinctive facial appearance, short stature and a mild biochemical and clinical phenotype

Background Isolated Complex I deficiency is the most common paediatric mitochondrial disease presentation, associated with poor prognosis and high mortality. Complex I comprises 44 structural subunits with at least 10 ancillary proteins; mutations in 29 of these have so far been associated with mitochondrial disease but there are limited genotype-phenotype correlations to guide clinicians to the correct genetic diagnosis. Methods Patients were analysed by whole-exome sequencing, targeted capture or candidate gene sequencing. Clinical phenotyping of affected individuals was performed. Results We identified a cohort of 10 patients from 8 families (7 families are of unrelated Irish ancestry) all of whom have short stature (C, p.Trp22Arg NDUFB3 variant. Two sibs presented with primary short stature without obvious metabolic dysfunction. Analysis of skeletal muscle from three patients confirmed a defect in Complex I assembly. Conclusions Our report highlights that the long-term prognosis related to the p.Trp22Arg NDUFB3 mutation can be good, even for some patients presenting in acute metabolic crisis with evidence of an isolated Complex I deficiency in muscle. Recognition of the distinctive facial features—particularly when associated with markers of mitochondrial dysfunction and/or Irish ancestry—should suggest screening for the p.Trp22Arg NDUFB3 mutation to establish a genetic diagnosis, circumventing the requirement of muscle biopsy to direct genetic investigations

Granzyme B-induced mitochondrial ROS are required for apoptosis

Caspases and the cytotoxic lymphocyte protease granzyme B (GB) induce reactive oxygen species (ROS) formation, loss of transmembrane potential and mitochondrial outer membrane permeabilization (MOMP). Whether ROS are required for GB-mediated apoptosis and how GB induces ROS is unclear. Here, we found that GB induces cell death in an ROS-dependent manner, independently of caspases and MOMP. GB triggers ROS increase in target cell by directly attacking the mitochondria to cleave NDUFV1, NDUFS1 and NDUFS2 subunits of the NADH: ubiquinone oxidoreductase complex I inside mitochondria. This leads to mitocentric ROS production, loss of complex I and III activity, disorganization of the respiratory chain, impaired mitochondrial respiration and loss of the mitochondrial cristae junctions. Furthermore, we have also found that GB-induced mitocentric ROS are necessary for optimal apoptogenic factor release, rapid DNA fragmentation and lysosomal rupture. Interestingly, scavenging the ROS delays and reduces many of the features of GB-induced death. Consequently, GB-induced ROS significantly promote apoptosis

African Linguistics in Central and Eastern Europe, and in the Nordic Countries

Non peer reviewe