307 research outputs found
The Next Generation Virgo Cluster Survey - Infrared (NGVS-IR): I. A new Near-UV/Optical/Near-IR Globular Cluster selection tool
The NGVS-IR project (Next Generation Virgo Survey - Infrared) is a contiguous
near-infrared imaging survey of the Virgo cluster of galaxies. It complements
the optical wide-field survey of Virgo (NGVS). The current state of NGVS-IR
consists of Ks-band imaging of 4 deg^2 centered on M87, and J and Ks-band
imaging of 16 deg^2 covering the region between M49 and M87. In this paper, we
present the observations of the central 4 deg^2 centered on Virgo's core
region. The data were acquired with WIRCam on the Canada-France-Hawaii
Telescope and the total integration time was 41 hours distributed in 34
contiguous tiles. A survey-specific strategy was designed to account for
extended galaxies while still measuring accurate sky brightness within the
survey area. The average 5\sigma limiting magnitude is Ks=24.4 AB mag and the
50% completeness limit is Ks=23.75 AB mag for point source detections, when
using only images with better than 0.7" seeing (median seeing 0.54"). Star
clusters are marginally resolved in these image stacks, and Virgo galaxies with
\mu_Ks=24.4 AB mag arcsec^-2 are detected. Combining the Ks data with optical
and ultraviolet data, we build the uiK color-color diagram which allows a very
clean color-based selection of globular clusters in Virgo. This diagnostic plot
will provide reliable globular cluster candidates for spectroscopic follow-up
campaigns needed to continue the exploration of Virgo's photometric and
kinematic sub-structures, and will help the design of future searches for
globular clusters in extragalactic systems. Equipped with this powerful new
tool, future NGVS-IR investigations based on the uiK diagram will address the
mapping and analysis of extended structures and compact stellar systems in and
around Virgo galaxies.Comment: 23 pages, 18 figures. Accepted for publication in ApJ
Room temperature chiral magnetic skyrmion in ultrathin magnetic nanostructures
Magnetic skyrmions are chiral spin structures with a whirling configuration.
Their topological properties, nanometer size and the fact that they can be
moved by small current densities have opened a new paradigm for the
manipulation of magnetisation at the nanoscale. To date, chiral skyrmion
structures have been experimentally demonstrated only in bulk materials and in
epitaxial ultrathin films and under external magnetic field or at low
temperature. Here, we report on the observation of stable skyrmions in
sputtered ultrathin Pt/Co/MgO nanostructures, at room temperature and zero
applied magnetic field. We use high lateral resolution X-ray magnetic circular
dichroism microscopy to image their chiral N\'eel internal structure which we
explain as due to the large strength of the Dzyaloshinskii-Moriya interaction
as revealed by spin wave spectroscopy measurements. Our results are
substantiated by micromagnetic simulations and numerical models, which allow
the identification of the physical mechanisms governing the size and stability
of the skyrmions.Comment: Submitted version. Extended version to appear in Nature
Nanotechnolog
Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context
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
Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas
This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing
molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin
Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas
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
Spatial Organization and Molecular Correlation of Tumor-Infiltrating Lymphocytes Using Deep Learning on Pathology Images
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
Live-attenuated influenza vaccine effectiveness against hospitalization in children aged 2-6 years, the first three seasons of the childhood influenza vaccination program in England, 2013/14-2015/16.
INTRODUCTION: In 2013, the United Kingdom began to roll-out a universal annual influenza vaccination program for children. An important component of any new vaccination program is measuring its effectiveness. Live-attenuated influenza vaccines (LAIVs) have since shown mixed results with vaccine effectiveness (VE) varying across seasons and countries elsewhere. This study aims to assess the effectiveness of influenza vaccination in children against severe disease during the first three seasons of the LAIV program in England. METHODS: Using the screening method, LAIV vaccination coverage in children hospitalized with laboratory-confirmed influenza infection was compared with vaccination coverage in 2-6-year-olds in the general population to estimate VE in 2013/14-2015/16. RESULTS: The overall LAIV VE, adjusted for age group, week/month and geographical area, for all influenza types pooled over the three influenza seasons was 50.1% (95% confidence interval [CI] 31.2, 63.8). By age, there was evidence of protection against hospitalization from influenza vaccination in both the pre-school (2-4-year-olds) (48.1%, 95% CI 27.2, 63.1) and school-aged children (5-6-year-olds) (62.6%, 95% CI 2.6, 85.6) over the three seasons. CONCLUSION: LAIV vaccination in children provided moderate annual protection against laboratory-confirmed influenza-related hospitalization in England over the three influenza seasons. This study contributes further to the limited literature to date on influenza VE against severe disease in children
Atypical Epstein-Barr Viral Genomic Structure in Lymphoma Tissue and Lymphoid Cell Lines
Epstein-Barr virus (EBV) DNA is found within the malignant cells of some subtypes of lymphoma, and viral presence is being exploited for improved diagnosis, monitoring, and management of affected patients. Recent work suggests that viral genomic polymorphism, such as partial deletion of the viral genome, could interfere with virus detection in tumor tissues. To test for atypical forms of the EBV genome, 98 lymphomas and 6 infected cell lines were studied using a battery of 6 quantitative polymerase chain reaction assays targeting disparate sections of EBV DNA. Fifty of the lymphomas (51%) had no amplifiable EBV DNA, and 38 lymphomas (39%) had low-level EBV infection that was deemed incidental based on EBV-encoded RNA (EBER) in situ hybridization results. The remaining 10 lymphomas (10%) had high EBV loads and EBER localization to malignant cells by EBER in situ hybridization. All 10 represented lymphoma subtypes were previously associated with EBV (Burkitt, diffuse large B-cell, or T-cell type), whereas no remnants of EBV were detected in other lymphoma subtypes (follicular, small lymphocytic, mantle cell, or marginal zone type). Interestingly, 4 of the 10 infected lymphomas had evidence of atypical viral genomes, including 3 of 4 infected T-cell lymphomas with aberrant loss of LMP2 amplicons, and a single diffuse large B-cell lymphoma lacking the central part of the viral genome spanning BamH1W, BZLF1, and EBNA1 gene segments. A reasonable screening strategy for infected malignancy involves applying EBER1 and LMP1 quantitative polymerase chain reaction assays and confirming that values exceeding 2000 copies of EBV per 100,000 cells have EBER localization to malignant cells
Stress degradation studies and development of stability-indicating TLC-densitometry method for determination of prednisolone acetate and chloramphenicol in their individual and combined pharmaceutical formulations
A rapid and reproducible stability indicating TLC method was developed for the determination of prednisolone acetate and chloramphenicol in presence of their degraded products. Uniform degradation conditions were maintained by refluxing sixteen reaction mixtures for two hours at 80°C using parallel synthesizer including acidic, alkaline and neutral hydrolysis, oxidation and wet heating degradation. Oxidation at room temperature, photochemical and dry heating degradation studies were also carried out. Separation was done on TLC glass plates, pre-coated with silica gel 60F-254 using chloroform: methanol (14:1 v/v). Spots at Rf 0.21 ± 0.02 and Rf 0.41 ± 0.03 were recognized as chloramphenicol and prednisolone acetate, respectively. Quantitative analysis was done through densitometric measurements at multiwavelength (243 nm, λmax of prednisolone acetate and 278 nm, λmax of chloramphenicol), simultaneously. The developed method was optimized and validated as per ICH guidelines. Method was found linear over the concentration range of 200-6000 ng/spot with the correlation coefficient (r2 ± S.D.) of 0.9976 ± 3.5 and 0.9920 ± 2.5 for prednisolone acetate and chloramphenicol, respectively. The developed TLC method can be applied for routine analysis of prednisolone acetate and chloramphenicol in presence of their degraded products in their individual and combined pharmaceutical formulations
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