Methicillin resistance is not a predictor of severity in community-acquired Staphylococcus aureus necrotizing pneumonia—results of a prospective observational study

AbstractStaphylococcal necrotizing pneumonia (NP) is a severe disease associated with Panton–Valentine leucocidin (PVL). NP was initially described for methicillin-susceptible Staphylococcus aureus (MSSA) infection, but cases associated with methicillin-resistant S. aureus (MRSA) infection have increased concomitantly with the incidence of community-acquired MRSA worldwide. The role of methicillin resistance in the severity of NP remains controversial. The characteristics and outcomes of 133 patients with PVL-positive S. aureus community-acquired pneumonia (CAP) were compared according to methicillin resistance. Data from patients hospitalized for PVL-positive S. aureus CAP in France from 1986 to 2010 were reported to the National Reference Centre for Staphylococci and were included in the study. The primary end point was mortality. Multivariate logistic modelling and the Cox regression were used for subsequent analyses. We analysed 29 cases of PVL-MRSA and 104 cases of PVL-MSSA pneumonia. Airway haemorrhages were more frequently associated with PVL-MSSA pneumonia. However, no differences in the initial severity or the management were found between these two types of pneumonia. The rate of lethality was 39% regardless of methicillin resistance. By Cox regression analysis, methicillin resistance was not found to be a significant independent predictor of mortality at 7 or 30 days (p 0.65 and p 0.71, respectively). Our study demonstrates that methicillin resistance is not associated with the severity of staphylococcal necrotizing pneumonia

Strain-induced Evolution of Electronic Band Structures in a Twisted Graphene Bilayer

Here we study the evolution of local electronic properties of a twisted graphene bilayer induced by a strain and a high curvature. The strain and curvature strongly affect the local band structures of the twisted graphene bilayer; the energy difference of the two low-energy van Hove singularities decreases with increasing the lattice deformations and the states condensed into well-defined pseudo-Landau levels, which mimic the quantization of massive Dirac fermions in a magnetic field of about 100 T, along a graphene wrinkle. The joint effect of strain and out-of-plane distortion in the graphene wrinkle also results in a valley polarization with a significant gap, i.e., the eight-fold degenerate Landau level at the charge neutrality point is splitted into two four-fold degenerate quartets polarized on each layer. These results suggest that strained graphene bilayer could be an ideal platform to realize the high-temperature zero-field quantum valley Hall effect.Comment: 4 figure

X-Ray Analysis of Oxygen-induced Perpendicular Magnetic Anisotropy in Pt/Co/AlOx trilayer

X-ray spectroscopy measurements have been performed on a series of Pt/Co/AlOx trilayers to investigate the role of Co oxidation in the perpendicular magnetic anisotropy of the Co/AlOx interface. It is observed that high temperature annealing modifies the magnetic properties of the Co layer, inducing an enhancement of the perpendicular magnetic anisotropy. The microscopic structural properties are analyzed via X-ray Absorption Spectroscopy, X-ray Magnetic Circular Dichroism and X-ray Photoelectron Spectroscopy measurements. It is shown that annealing enhances the amount of interfacial oxide, which may be at the origin of a strong perpendicular magnetic anisotropy

Contrasting the Harmonic Balance and Linearized Methods for Oscillating-Flap Simulations

In the framework of unsteady aerodynamics, forced-harmonic-motion simulations can be used to compute unsteady loads. In this context, the present paper assesses two alternatives to the unsteady Reynolds-averaged Navier–Stokes approach, the linearized unsteady Reynolds-averaged Navier–Stokes equations method, and the harmonic balance approach. The test case is a NACA 64A006 airfoil with an oscillating ␣ap mounted at 75% of the chord. Emphasis is put on examining the performances of the methods in terms of accuracy and computational cost over a range of physical conditions. It is found that, for a subsonic ␣ow, the linearized unsteady Reynolds-averaged Navier–Stokes method is the most ef␣cient one. In the transonic regime, the linearized unsteady Reynolds-averaged Navier–Stokes method remains the fastest approach, but with limited accuracy around shocks, whereas a one- harmonic harmonic balance solution is in closer agreement with the unsteady Reynolds-averaged Navier–Stokes solution. In the case of separation in the transonic regime, the linearized unsteady Reynolds-averaged Navier–Stokes method fails to converge, whereas the harmonic balance remains robust and accurate

Muscleblind-Like 1 Knockout Mice Reveal Novel Splicing Defects in the Myotonic Dystrophy Brain

Myotonic dystrophy type 1 (DM1) is a multi-systemic disorder caused by a CTG trinucleotide repeat expansion (CTGexp) in the DMPK gene. In skeletal muscle, nuclear sequestration of the alternative splicing factor muscleblind-like 1 (MBNL1) explains the majority of the alternative splicing defects observed in the HSALR transgenic mouse model which expresses a pathogenic range CTGexp. In the present study, we addressed the possibility that MBNL1 sequestration by CUGexp RNA also contributes to splicing defects in the mammalian brain. We examined RNA from the brains of homozygous Mbnl1ΔE3/ΔE3 knockout mice using splicing-sensitive microarrays. We used RT-PCR to validate a subset of alternative cassette exons identified by microarray analysis with brain tissues from Mbnl1ΔE3/ΔE3 knockout mice and post-mortem DM1 patients. Surprisingly, splicing-sensitive microarray analysis of Mbnl1ΔE3/ΔE3 brains yielded only 14 candidates for mis-spliced exons. While we confirmed that several of these splicing events are perturbed in both Mbnl1 knockout and DM1 brains, the extent of splicing mis-regulation in the mouse model was significantly less than observed in DM1. Additionally, several alternative exons, including Grin1 exon 4, App exon 7 and Mapt exons 3 and 9, which have previously been reported to be aberrantly spliced in human DM1 brain, were spliced normally in the Mbnl1 knockout brain. The sequestration of MBNL1 by CUGexp RNA results in some of the aberrant splicing events in the DM1 brain. However, we conclude that other factors, possibly other MBNL proteins, likely contribute to splicing mis-regulation in the DM1 brain

Soil measurements during HAPEX-Sahel intensive observation period

This article describes measurements made at each site and for each vegetation cover as part of the soils program for the HAPEX-Sahel regional scale experiment. The measurements were based on an initial sampling scheme and included profile soil water content, surface soil water content, soil water potential, infiltration rates, additional measurements on core samples, and grain size analysis. The measurements were used to categorize the state of the surface and profile soil water regimes during the experiment and to derive functional relationships for the soil water characteristic curve, unsaturated hydraulic conductivity function, and infiltration function. Sample results for different supersites and different vegetation covers are presented showing soil water profiles and total soil water storage on days corresponding to the experimental ‘Golden Days’. Sample results are also presented for spatial and temporal distribution of surface moisture content and infiltration tests. The results demonstrate that the major experimental objective of monitoring the supersites during the most rapid vegetative growth stage with the largest change of the surface energy balance following the rainy season was very nearly achieved. Separation of the effects of probable root activity and drainage of the soil profile is possible. The potential for localized advection between the bare soil and vegetation strips of the tiger bush sites is demonstrate

Systematic and Evolutionary Insights Derived from mtDNA COI Barcode Diversity in the Decapoda (Crustacea: Malacostraca)

Background: Decapods are the most recognizable of all crustaceans and comprise a dominant group of benthic invertebrates of the continental shelf and slope, including many species of economic importance. Of the 17635 morphologically described Decapoda species, only 5.4% are represented by COI barcode region sequences. It therefore remains a challenge to compile regional databases that identify and analyse the extent and patterns of decapod diversity throughout the world. Methodology/Principal Findings: We contributed 101 decapod species from the North East Atlantic, the Gulf of Cadiz and the Mediterranean Sea, of which 81 species represent novel COI records. Within the newly-generated dataset, 3.6% of the species barcodes conflicted with the assigned morphological taxonomic identification, highlighting both the apparent taxonomic ambiguity among certain groups, and the need for an accelerated and independent taxonomic approach. Using the combined COI barcode projects from the Barcode of Life Database, we provide the most comprehensive COI data set so far examined for the Order (1572 sequences of 528 species, 213 genera, and 67 families). Patterns within families show a general predicted molecular hierarchy, but the scale of divergence at each taxonomic level appears to vary extensively between families. The range values of mean K2P distance observed were: within species 0.285% to 1.375%, within genus 6.376% to 20.924% and within family 11.392% to 25.617%. Nucleotide composition varied greatly across decapods, ranging from 30.8 % to 49.4 % GC content. Conclusions/Significance: Decapod biological diversity was quantified by identifying putative cryptic species allowing a rapid assessment of taxon diversity in groups that have until now received limited morphological and systematic examination. We highlight taxonomic groups or species with unusual nucleotide composition or evolutionary rates. Such data are relevant to strategies for conservation of existing decapod biodiversity, as well as elucidating the mechanisms and constraints shaping the patterns observed.FCT - SFRH/BD/25568/ 2006EC FP6 - GOCE-CT-2005-511234 HERMESFCT - PTDC/MAR/69892/2006 LusomarBo