713 research outputs found
Carbonate alteration of ophiolitic rocks in the Arabian–Nubian Shield of Egypt: sources and compositions of the carbonating fluid and implications for the formation of Au deposits
Ultramafic portions of ophiolitic fragments in the Arabian–Nubian Shield (ANS) show pervasive carbonate alteration forming various degrees of carbonated serpentinites and listvenitic rocks. Notwithstanding the extent of the alteration, little is known about the processes that caused it, the source of the CO2 or the conditions of alteration. This study investigates the mineralogy, stable (O, C) and radiogenic (Sr) isotope composition, and geochemistry of suites of variably carbonate altered ultramafics from the Meatiq area of the Central Eastern Desert (CED) of Egypt. The samples investigated include least-altered lizardite (Lz) serpentinites, antigorite (Atg) serpentinites and listvenitic rocks with associated carbonate and quartz veins. The C, O and Sr isotopes of the vein samples cluster between −8.1‰ and −6.8‰ for δ13C, +6.4‰ and +10.5‰ for δ18O, and 87Sr/86Sr of 0.7028–0.70344, and plot within the depleted mantle compositional field. The serpentinites isotopic compositions plot on a mixing trend between the depleted-mantle and sedimentary carbonate fields. The carbonate veins contain abundant carbonic (CO2±CH4±N2) and aqueous-carbonic (H2O-NaCl-CO2±CH4±N2) low salinity fluid, with trapping conditions of 270–300°C and 0.7–1.1 kbar. The serpentinites are enriched in Au, As, S and other fluid-mobile elements relative to primitive and depleted mantle. The extensively carbonated Atg-serpentinites contain significantly lower concentrations of these elements than the Lz-serpentinites suggesting that they were depleted during carbonate alteration. Fluid inclusion and stable isotope compositions of Au deposits in the CED are similar to those from the carbonate veins investigated in the study and we suggest that carbonation of ANS ophiolitic rocks due to influx of mantle-derived CO2-bearing fluids caused break down of Au-bearing minerals such as pentlandite, releasing Au and S to the hydrothermal fluids that later formed the Au-deposits. This is the first time that gold has been observed to be remobilized from rocks during the lizardite–antigorite transition
Imperceptible CMOS camera dazzle for adversarial attacks on deep neural networks
Despite the outstanding performance of deep neural networks, they are
vulnerable to adversarial attacks. While there are many invisible attacks in
the digital domain, most physical world adversarial attacks are visible. Here
we present an invisible optical adversarial attack that uses a light source to
dazzle a CMOS camera with a rolling shutter. We present the photopic conditions
required to keep the attacking light source completely invisible while
sufficiently jamming the captured image so that a deep neural network applied
to it is deceived.Comment: 12 pages, 10 figure
Improving decision making in the management of hospital readmissions using modern survival analysis techniques
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
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
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
Long-term CT follow-up of patients with lumbar spondylolysis reveals low rate of spontaneous bone fusion
OBJECTIVES: Knowledge about the long-term outcome of patients with lumbar spondylolysis (LS) is limited. This study assessed the frequency of bone fusion in conservatively treated lumbar spondylolysis with photon counting detector computed tomography.
METHODS: Patients with lumbar spondylolysis diagnosed with CT or MRI were prospectively enrolled and underwent CT 5-10 years after initial imaging. Image assessment included evaluation of Meyerding grade, listhesis size, measurement of the lysis gap, and disc integrity on the lysis level. Comparisons were made between bone fusion as the primary endpoint and sex, body mass index, age at diagnosis, follow-up interval, size of listhesis, Meyerding grade, size of the lysis gap, sports activity, and presence of pain.
RESULTS: A total of 39 patients (26.0 +/- 3.1 years, 15 female) with lumbar spondylolysis on 41 levels were included after a mean follow-up period of 9.1 +/- 2.2 years. Nine patients (22.0%, four female) showed complete fusion of the lysis gap. Patients with bone fusion of the lysis gap had a significantly lower Meyerding grade (p = 0.01), smaller size of the listhesis (p = 0.019), and smaller anterior and posterior lysis gap size (p = 0.046 and p = 0.011, respectively). Unilateral lyses showed significantly higher fusion rates than bilateral lyses (40.0% vs. 16.1%, p = 0.01). No statistically significant difference was found for pain at follow-up between patients with and without bone fusion (p = 0.253).
CONCLUSION: Bone fusion occurred in about a fifth of conservatively treated lumbar spondylolysis after a follow-up period of 9 years. Factors associated with a successful fusion were a lower Meyerding grade, minimal listhesis, and a small lysis gap
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