481 research outputs found
Investigation of the thermal stability of Mg/Co periodic multilayers for EUV applications
We present the results of the characterization of Mg/Co periodic multilayers
and their thermal stability for the EUV range. The annealing study is performed
up to a temperature of 400\degree C. Images obtained by scanning transmission
electron microscopy and electron energy loss spectroscopy clearly show the good
quality of the multilayer structure. The measurements of the EUV reflectivity
around 25 nm (~49 eV) indicate that the reflectivity decreases when the
annealing temperature increases above 300\degreeC. X-ray emission spectroscopy
is performed to determine the chemical state of the Mg atoms within the Mg/Co
multilayer. Nuclear magnetic resonance used to determine the chemical state of
the Co atoms and scanning electron microscopy images of cross sections of the
Mg/Co multilayers reveal changes in the morphology of the stack from an
annealing temperature of 305\degreee;C. This explains the observed reflectivity
loss.Comment: Published in Applied Physics A: Materials Science \& Processing
Published at
http://www.springerlink.com.chimie.gate.inist.fr/content/6v396j6m56771r61/ 21
page
Genetic variations within human gained enhancer elements affect human brain sulcal morphology.
The expansion of the cerebral cortex is one of the most distinctive changes in the evolution of the human brain. Cortical expansion and related increases in cortical folding may have contributed to emergence of our capacities for high-order cognitive abilities. Molecular analysis of humans, archaic hominins, and non-human primates has allowed identification of chromosomal regions showing evolutionary changes at different points of our phylogenetic history. In this study, we assessed the contributions of genomic annotations spanning 30 million years to human sulcal morphology measured via MRI in more than 18,000 participants from the UK Biobank. We found that variation within brain-expressed human gained enhancers, regulatory genetic elements that emerged since our last common ancestor with Old World monkeys, explained more trait heritability than expected for the left and right calloso-marginal posterior fissures and the right central sulcus. Intriguingly, these are sulci that have been previously linked to the evolution of locomotion in primates and later on bipedalism in our hominin ancestors
The Microbiology of Community-acquired Peritonitis in Children
BACKGROUND: microbiologic data are lacking regarding pediatric community-acquired peritonitis (CAP).
METHODS: we conducted a 2-year retrospective single center study. Consecutive children undergoing CAP surgery were included. Microbiology and antimicrobial susceptibility of peritoneal isolates were analyzed.
RESULTS: a total of 70 children from 3 months to 14 years of age were included. A total of 123 bacterial isolates were analyzed. Escherichia coli was the predominant aerobic organism (51% of isolates); 54.8% were susceptible to amoxicillin whereas 90.3% were susceptible to amoxicillin-clavulanate. Anaerobes accounted for 29% of isolates, and 94.3% of strains were susceptible to amoxicillin-clavulanate and 68.5% were susceptible to clindamycin. Pseudomonas aeruginosa was present in 6% of isolates and in 10% of children. The presence of E. coli resistant to amoxicillin or to amoxicillin-clavulanate was the only independent risk factor associated with postoperative peritonitis.
CONCLUSION: microbiology of pediatric CAP is similar to adult CAP with a predominancy of E. coli and anaerobes. P. aeruginosa in peritoneal samples had no apparent influence on the outcome
Non-Dipolar Electron Angular Distributions from Fixed-in-Space Molecules
The first indication of nondipole effects in the azimuthal dependence of photoelectron angular distributions emitted from fixed-in-space molecules is demonstrated in N2. Comparison of the results with angular distributions observed for randomly oriented molecules and theoretical derivations for the nondipole correction first order in photon momentum suggests that higher orders will be needed to describe distributions measured in the molecular frame
Transcriptome Sequencing of Hevea brasiliensis for Development of Microsatellite Markers and Construction of a Genetic Linkage Map
To obtain more information on the Hevea brasiliensis genome, we sequenced the transcriptome from the vegetative shoot apex yielding 2 311 497 reads. Clustering and assembly of the reads produced a total of 113 313 unique sequences, comprising 28 387 isotigs and 84 926 singletons. Also, 17 819 expressed sequence tag (EST)-simple sequence repeats (SSRs) were identified from the data set. To demonstrate the use of this EST resource for marker development, primers were designed for 430 of the EST-SSRs. Three hundred and twenty-three primer pairs were amplifiable in H. brasiliensis clones. Polymorphic information content values of selected 47 SSRs among 20 H. brasiliensis clones ranged from 0.13 to 0.71, with an average of 0.51. A dendrogram of genetic similarities between the 20 H. brasiliensis clones using these 47 EST-SSRs suggested two distinct groups that correlated well with clone pedigree. These novel EST-SSRs together with the published SSRs were used for the construction of an integrated parental linkage map of H. brasiliensis based on 81 lines of an F1 mapping population. The map consisted of 97 loci, consisting of 37 novel EST-SSRs and 60 published SSRs, distributed on 23 linkage groups and covered 842.9 cM with a mean interval of 11.9 cM and ∼4 loci per linkage group. Although the numbers of linkage groups exceed the haploid number (18), but with several common markers between homologous linkage groups with the previous map indicated that the F1 map in this study is appropriate for further study in marker-assisted selection
Introduction of Zr in nanometric periodic Mg/Co multilayers
We study the introduction of a third material, namely Zr, within a nanometric
periodic Mg/Co structure designed to work as optical component in the extreme
UV (EUV) spectral range. Mg/Co, Mg/Zr/Co, Mg/Co/Zr and Mg/Zr/Co/Zr multilayers
are designed, then characterized in terms of structural quality and optical
performances through X-ray and EUV reflectometry measurements respectively. For
the Mg/Co/Zr structure, the reflectance value is equal to 50% at 25.1 nm and
45deg of grazing incidence and reaches 51.3% upon annealing at 200deg C.
Measured EUV reflectivity values of tri-layered systems are discussed in terms
of material order within a period and compared to the predictions of the
theoretical model of Larruquert. Possible applications are pointed out.Comment: 19 page
KL∗VS heterozygosity reduces brain amyloid in asymptomatic at-risk APOE∗4 carriers
KLOTHO∗VS heterozygosity (KL∗VSHET+) was recently shown to be associated with reduced risk of Alzheimer's disease (AD) in APOE∗4 carriers. Additional studies suggest that KL∗VSHET+ protects against amyloid burden in cognitively normal older subjects, but sample sizes were too small to draw definitive conclusions. We performed a well-powered meta-analysis across 5 independent studies, comprising 3581 pre-clinical participants ages 60–80, to investigate whether KL∗VSHET+ reduces the risk of having an amyloid-positive positron emission tomography scan. Analyses were stratified by APOE∗4 status. KL∗VSHET+ reduced the risk of amyloid positivity in APOE∗4 carriers (odds ratio = 0.67 [0.52–0.88]; p = 3.5 × 10−3), but not in APOE∗4 non-carriers (odds ratio = 0.94 [0.73–1.21]; p = 0.63). The combination of APOE∗4 and KL∗VS genotypes should help enrich AD clinical trials for pre-symptomatic subjects at increased risk of developing amyloid aggregation and AD. KL-related pathways may help elucidate protective mechanisms against amyloid accumulation and merit exploration for novel AD drug targets. Future investigation of the biological mechanisms by which KL interacts with APOE∗4 and AD are warranted
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