859 research outputs found
OBSERVATIONS OF PROPERTIES OF SINTERED WROUGHT TUNGSTEN SHEET AT VERY HIGH TEMPERATURES
Examination of mechanical properties of tungsten sheet at very high temperature
The accessible regions presentation of gravity-assisted trajectories using Jupiter
Accessibility of solar system regions to earth launched spacecraft using Jupiter gravity- assisted trajectorie
The ruminal level of trans-10 fatty acids of dairy cows is linked to the composition of bacterial community
The ruminal level of trans-10 fatty acids of dairy cows is linked to the composition of bacterial communit
Bioresorbable Film for the Prevention of Adhesion to the Anterior Spine After Anterolateral Discectomy
Background context The development of scar tissue and adhesions postoperatively is a natural consequence of healing but can be associated with medical complications and render reoperation difficult. Many biocompatible products have been evaluated as barriers or deterrents to adhesions. Purpose To evaluate the efficacy of a bioresorbable polylactide film as a barrier to adhesion formation after anterolateral discectomy. Study design Experimental study. Methods Seven, skeletally mature female sheep underwent a retroperitoneal approach to the anterolateral lumbar spine. A discectomy was performed at two levels with an intervening unoperated disc site. One site was treated with a polylactide film barrier (Hydrosorb Shield; MacroPore Biosurgery, San Diego, CA) affixed with tacks manufactured from the same material. The second site was left untreated. Treatment and control sites were randomly assigned. Postmortem analysis included scar tenacity scoring on five spines and histological evaluation on two spines. Results The application of the Hydrosorb film barrier allowed a definite dissection plane during scar tenacity scoring and there was a significant difference in the development of adhesions to the disc between the control and treated sites. Histological evaluation revealed evidence of barrier formation to scar tissue and no significant adverse inflammatory reactions. Conclusions Hydrosorb Shield appears to be an effective postoperative barrier to scar tissue adhesion after anterolateral discectomy. The use of polylactide tacks was beneficial to affix the barrier film in place. Safety issues associated with delayed healing or adverse response to the film or tacks were not observed. Hydrosorb film may be useful as an antiadhesion barrier facilitating dissection during surgical revision in anterior approaches to the spine. Further studies are indicated to evaluate the performance of the bioresorbable material as an antiadhesion barrier in techniques of spinal fusion and disc replacement
CX3CR1 Polymorphisms are associated with atopy but not asthma in German children
Chemokines and their receptors are involved in many aspects of immunity. Chemokine CX3CL1, acting via its receptor CX3CR1, regulates monocyte migration and macrophage differentiation as well as T cell-dependent inflammation. Two common, nonsynonymous polymorphisms in CX3CR1 have previously been shown to alter the function of the CX3CL1/CX3CR1 pathway and were suggested to modify the risk for asthma. Using matrix-assisted laser desorption/ionization time-of-flight technology, we genotyped polymorphisms Val249Ile and Thr280Met in a cross-sectional population of German children from Munich (n = 1,159) and Dresden ( n = 1,940). For 249Ile an odds ratio of 0.77 (95% confidence interval 0.63-0.96; p = 0.017) and for 280Met an odds ratio of 0.71 ( 95% confidence interval 0.56-0.89; p = 0.004) were found with atopy in Dresden but not in Munich. Neither polymorphism was associated with asthma. Thus, amino acid changes in CX3CR1 may influence the development of atopy but not asthma in German children. Potentially, other factors such as environmental effects may modify the role of CX3CR1 polymorphisms. Copyright (c) 2007 S. Karger AG, Basel
175 GHz, 400-fs-pulse harmonically mode-locked surface emitting semiconductor laser
We report a harmonically mode-locked vertical external cavity surface emitting laser (VECSEL) producing 400 fs pulses at a repetition frequency of 175 GHz with an average output power of 300 mW. Harmonic mode-locking was established using a 300 µm thick intracavity single crystal diamond heat spreader in thermal contact with the front surface of the gain sample using liquid capillary bonding. The repetition frequency was set by the diamond microcavity and stable harmonic mode locking was achieved when the laser cavity length was tuned so that the laser operated on the 117th harmonic of the fundamental cavity. When an etalon placed intracavity next to the gain sample, but not in thermal contact was used pulse groups were observed. These contained 300 fs pulses with a spacing of 5.9 ps. We conclude that to achieve stable harmonic mode locking at repetition frequencies in the 100s of GHz range in a VECSEL there is a threshold pulse energy above which harmonic mode locking is achieved and below which groups of pulses are observed
Identification and characterization of copy number variations in cattle
Copy number variations (CNVs) are an important source of genetic changes. They are defined as a gain or loss of genomic region ranging from 50 bp to several megabases. CNVs have been shown to be associated with many diseases and some phenotypic traits in several species, including cattle. We used Pindel, Delly, BreakDancer, and CNVnator to identify CNVs using whole-genome sequencing data of 200 animals from eight French dairy and beef cattle breeds. We selected only deletions and duplications predicted by at least two tools and present in at least two animals. We identified a total of 29,132 autosomal deletions and duplications which cover between 31 to 34% (784 to 865 Mb) of the autosomal genome, with an average of 6,000 events per animal. Among these deletions and duplications, 27,690 were present in at least two animals. Out of theses, 26,417 events were deletions, 674 were duplications and 599 regions were both (deletion and duplication within the same region). We defined a CNV as deletion and duplication in the same region, and we termed this region as CNV-Region (CNVR). The size of CNVRs ranged from 100 bp to 9.3 Mb with a median of 1.3 kb and a mean of 45 kb. From the identified deletions and duplications, 8,283 overlapped with 9,733 annotated genes including 290 CNVRs overlapping with 974 annotated genes, including some genes known to be implicated in some traits of economic importance. Our study provides an extensive view of the CNVRs in French dairy and beef breeds. CNVRs with an effect on some commercially interesting phenotypes could be used to improve genetic selection of these eight French breeds
Expanding Duplication of Free Fatty Acid Receptor-2 (GPR43) Genes in the Chicken Genome
International audienceFree fatty acid receptors (FFAR) belong to a family of five G-protein coupled receptors that are involved in the regulation of lipidmetabolism, so that their loss of function increases the risk of obesity. The aim of this study was to determine the expansion of genesencoding paralogs of FFAR2 in the chicken, considered as amodel organism for developmental biology and biomedical research. Byestimating the gene copy number using quantitative polymerase chain reaction, genomic DNA resequencing, and RNA sequencingdata, we showed the existence of 23 ±1.5 genes encoding FFAR2 paralogs in the chicken genome. The FFAR2 paralogs shared anidentity from 87.2%up to 99%. Extensive gene conversion was responsible for this high degree of sequence similarities betweenthese genes, and this concerned especially the four amino acids known to be critical for ligand binding. Moreover, elevated nonsynonymous/synonymous substitutionratios onsomeamino acids withinor inclose-vicinity of the ligand-bindinggroove suggest thatpositive selectionmay have reduced the effective rate of gene conversion in this region, thus contributing to diversify the function ofsome FFAR2 paralogs. All the FFAR2 paralogs were located on a microchromosome in a same linkage group. FFAR2 genes wereexpressed in different tissues and cells such as spleen, peripheral blood mononuclear cells, abdominal adipose tissue, intestine, andlung, with the highest rate of expression in testis. Further investigations are needed to determine whether these chicken-specificevents along evolution are the consequence of domestication and may play a role in regulating lipid metabolism in this species
Comparison between Transcriptome Sequencing and 16S Metagenomics for Detection of Bacterial Pathogens in Wildlife
Background Rodents are major reservoirs of pathogens responsible for numerous zoonotic diseases in humans and livestock. Assessing their microbial diversity at both the individual and population level is crucial for monitoring endemic infections and revealing microbial association patterns within reservoirs. Recently, NGS approaches have been employed to characterize microbial communities of different ecosystems. Yet, their relative efficacy has not been assessed. Here, we compared two NGS approaches, RNA-Sequencing (RNA-Seq) and 16S-metagenomics, assessing their ability to survey neglected zoonotic bacteria in rodent populations.Methodology/Principal Findings : We first extracted nucleic acids from the spleens of 190 voles collected in France. RNA extracts were pooled, randomly retro-transcribed, then RNA-Seq was performed using HiSeq. Assembled bacterial sequences were assigned to the closest taxon registered in GenBank. DNA extracts were analyzed via a 16S-metagenomics approach using two sequencers: the 454 GS-FLX and the MiSeq. The V4 region of the gene coding for 16S rRNA was amplified for each sample using barcoded universal primers. Amplicons were multiplexed and processed on the distinct sequencers. The resulting datasets were de-multiplexed, and each read was processed through a pipeline to be taxonomically classified using the Ribosomal Database Project. Altogether, 45 pathogenic bacterial genera were detected. The bacteria identified by RNA-Seq were comparable to those detected by 16S-metagenomics approach processed with MiSeq (16S-MiSeq). In contrast, 21 of these pathogens went unnoticed when the 16S-metagenomics approach was processed via 454-pyrosequencing (16S-454). In addition, the 16S-metagenomics approaches revealed a high level of coinfection in bank voles. Conclusions/Significance :We concluded that RNA-Seq and 16S-MiSeq are equally sensitive in detecting bacteria. Although only the 16S-MiSeq method enabled identification of bacteria in each individual reservoir, with subsequent derivation of bacterial prevalence in host populations, and generation of intra-reservoir patterns of bacterial interactions. Lastly, the number of bacterial reads obtained with the 16S-MiSeq could be a good proxy for bacterial prevalence
The Impact of SARS-COVID-19 Outbreak on European Cities Urban Mobility
The global outbreak of the SARS-COVID-19 pandemic has changed our lives, driving an unprecedented transformation of our habits. In response, the authorities have enforced several measures, including social distancing and travel restrictions that lead to the temporary closure of activities centered around schools, companies, local businesses to those pertaining to the recreation category. As such, with a mobility reduction, the life of our cities during the outbreak changed significantly. In this paper, we aim at drawing attention to this problem and perform an analysis for multiple cities through crowdsensed information available from datasets such as Apple Maps, to shed light on the changes undergone during both the outbreak and the recovery. Specifically, we exploit data characterizing many mobility modes like driving, walking, and transit. With the use of Gaussian Processes and clustering techniques, we uncover patterns of similarity between the major European cities. Further, we perform a prediction analysis that permits forecasting the trend of the recovery process and exposes the deviation of each city from the trend of the cluster. Our results unveil that clusters are not typically formed by cities with geographical ties, but rather on the spread of the infection, lockdown measures, and citizens’ reactions
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