145 research outputs found

    Continuous Solar Simulator for Concentrator Photovoltaic Systems

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    A continuous solar simulator for measuring performance of concentrator photovoltaic (CPV) systems is presented. The illumination system is based on a Xenon lamp, a homogenizer rod, shaping optics and a 30cm diameter collimator. The design optimises the reproduction of the characteristics of direct solar illumination: 32’ divergence, high spatial homogeneity, sun-like spectral distribution, with a maximum intensity of 250W/m². It accommodates pass-band and attenuation filters to tune the beam output. It operates in continuous mode, allowing to investigate CPV thermal aspects as well. The present paper addresses the concept design of the solar simulator and associated performance results

    Impact of medical practice guidelines on the assessment of patients with acute coronary syndrome without persistent ST segment elevation

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    Objective. To assess the impact of introducing clinical practice guidelines on acute coronary syndrome without persistent ST segment elevation (ACS) on patient initial assessment. Design. Prospective before-after evaluation over a 3-month period. Setting. The emergency ward of a tertiary teaching hospital. Patients. All consecutive patients with ACS evaluated in the emergency ward over the two 3-month periods. Intervention. Implementation of the practice guidelines, and the addition of a cardiology consultant to the emergency team. Main outcome measures. Diagnosis, electrocardiogram interpretation, and risk stratification after the initial evaluation. Results. The clinical characteristics of the 328 and 364 patients evaluated in the emergency ward for suspicion of ACS before and after guideline implementation were similar. Significantly more patients were classified as suffering from atypical chest pain (39.6% versus 47.0%; P = 0.006) after guideline implementation. Guidelines availability was associated with significantly more formal diagnoses (79.9% versus 92.9%; P < 0.0001) and risk stratification (53.7% versus 65.4%, P < 0.0001) at the end of initial assessment. Conclusion. Guidelines implementation, along with availability of a cardiology consultant in the emergency room had a positive impact on initial assessment of patients evaluated for suspicion of ACS. It led to increased confidence in diagnosis and stratification by risk, which are the first steps in initiating effective treatment for this common conditio

    Intact satellite cells lead to remarkable protection against Smn gene defect in differentiated skeletal muscle

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    Deletion of murine Smn exon 7, the most frequent mutation found in spinal muscular atrophy, has been directed to either both satellite cells, the muscle progenitor cells and fused myotubes, or fused myotubes only. When satellite cells were mutated, mutant mice develop severe myopathic process, progressive motor paralysis, and early death at 1 mo of age (severe mutant). Impaired muscle regeneration of severe mutants correlated with defect of myogenic precursor cells both in vitro and in vivo. In contrast, when satellite cells remained intact, mutant mice develop similar myopathic process but exhibit mild phenotype with median survival of 8 mo and motor performance similar to that of controls (mild mutant). High proportion of regenerating myofibers expressing SMN was observed in mild mutants compensating for progressive loss of mature myofibers within the first 6 mo of age. Then, in spite of normal contractile properties of myofibers, mild mutants develop reduction of muscle force and mass. Progressive decline of muscle regeneration process was no more able to counterbalance muscle degeneration leading to dramatic loss of myofibers. These data indicate that intact satellite cells remarkably improve the survival and motor performance of mutant mice suffering from chronic myopathy, and suggest a limited potential of satellite cells to regenerate skeletal muscle

    Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

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    Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

    Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

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    Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN

    Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

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    This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin

    Spatial Organization and Molecular Correlation of Tumor-Infiltrating Lymphocytes Using Deep Learning on Pathology Images

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    Beyond sample curation and basic pathologic characterization, the digitized H&E-stained images of TCGA samples remain underutilized. To highlight this resource, we present mappings of tumorinfiltrating lymphocytes (TILs) based on H&E images from 13 TCGA tumor types. These TIL maps are derived through computational staining using a convolutional neural network trained to classify patches of images. Affinity propagation revealed local spatial structure in TIL patterns and correlation with overall survival. TIL map structural patterns were grouped using standard histopathological parameters. These patterns are enriched in particular T cell subpopulations derived from molecular measures. TIL densities and spatial structure were differentially enriched among tumor types, immune subtypes, and tumor molecular subtypes, implying that spatial infiltrate state could reflect particular tumor cell aberration states. Obtaining spatial lymphocytic patterns linked to the rich genomic characterization of TCGA samples demonstrates one use for the TCGA image archives with insights into the tumor-immune microenvironment
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