223 research outputs found

    Quantitative mineral resource assessment of undiscovered porphyry copper resources in South America

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    A quantitative resource assessment to be published this fall identifies and evaluates 26 tracts in South America where the geology isconsidered permissive for the occurrence of porphyry copper deposits. For each tract, information is provided on: (1) the rationale fordelineating the tract, (2) examples of important deposits in the tract, (3) the rationale for choosing the mineral deposit model used forthe assessment, (4) exploration history, and (5) expected spatial distribution of undiscovered deposits in the tract. The scale used toevaluate geologic information and define tracts is 1:1,000,000. There are about 600 million tonnes of copper in known porphyry copper deposits in South America. This study estimates there areapproximately 720 million tonnes of additional copper in undiscovered porphyry copper deposits, yielding a combined endowment ofabout 1.3 billion tonnes of copper. There are about 69 known porphyry copper deposits using the criteria adopted here to define a well-explored deposit. This study estimates that a mean of about 140 deposits remain to be found. In other words, about twice as manynew deposits might be found as have already been found. Overall, deposit densities in South America are comparable to those in therest of the world but differ in important details that are reflected in mapped distributions of deposits, metal densities, and percentagesof undiscovered deposits in each tract. The deposits in the tracts that include Chuquicamata and El Teniente are significantly larger intonnage and grade and are reported in a separate model that is more representative of their characteristics. The results of theassessment afirm that not all porphyry copper deposits in South America are located in the Andes. Geologic indications support thepresence of undiscovered deposits in Patagonia as well as the Amazon of Brazil. A preliminary 1:4,000,000 map of the 26 tracts will bedisplayed

    A preliminary quantitative mineral resource assessment of undiscovered porphyry copper resources in the Andes mountains of South America

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    Quantitative information on the probable locations and amounts of undiscovered porphyry copper resources of the world is important to international exploration managers, land-use and environmental planners, economists, and policy makers. The U.S. Geological Survey is organizing and facilitating a cooperative assessment, in collaboration with interested geological surveys and geological organizations, of the likely global distribution, quantity, and quality of selected undiscovered nonfuel mineral resources. This report on undiscovered porphyry copper deposits of the Andes Mountains was produced jointly with the geological surveys of Argentina, Chile, Colombia, and Peru, and is a summary of the more extensive report (>300 pages) that will be published soon. Reports on undiscovered copper resources of other regions of the world are being prepared and will be followed by assessments of the global undiscovered resources of platinum-group minerals and potash

    Some biomarkers of acute kidney injury are increased in pre-renal acute injury

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    Pre-renal acute kidney injury (AKI) is assumed to represent a physiological response to underperfusion. Its diagnosis is retrospective after a transient rise in plasma creatinine, usually associated with evidence of altered tubular transport, particularly that of sodium. In order to test whether pre-renal AKI is reversible because injury is less severe than that of sustained AKI, we measured urinary biomarkers of injury (cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), γ-glutamyl transpeptidase, IL-18, and kidney injury molecule-1 (KIM-1)) at 0, 12, and 24 h following ICU admission. A total of 529 patients were stratified into groups having no AKI, AKI with recovery by 24 h, recovery by 48 h, or the composite of AKI greater than 48 h or dialysis. Pre-renal AKI was identified in 61 patients as acute injury with recovery within 48 h and a fractional sodium excretion <1%. Biomarker concentrations significantly and progressively increased with the duration of AKI. After restricting the AKI recovery within the 48 h cohort to pre-renal AKI, this increase remained significant. The median concentration of KIM-1, cystatin C, and IL-18 were significantly greater in pre-renal AKI compared with no-AKI, while NGAL and γ-glutamyl transpeptidase concentrations were not significant. The median concentration of at least one biomarker was increased in all but three patients with pre-renal AKI. Thus, the reason why some but not all biomarkers were increased requires further study. The results suggest that pre-renal AKI represents a milder form of injury

    Pan-American quantitative mineral resource assessment of copper, molybdenum, gold, and silver in undiscovered porphyry copper deposits in the Andes mountains, South America

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    Working together, the geological surveys of Argentina, Chile, Colombia, Peru, and the United States used the U. S. Geological Survey three-part mineral resource assessment methodology (Singer, 1993) to delineate the regional locations and make probabilistic estimates of the amounts of copper, molybdenum, silver, and gold in undiscovered porphyry copper deposits in the Andes. Quantitative information on the probable locations and amounts of undiscovered mineral resources of the world is important to exploration managers, land-use and environmental planners, economists, and policy makers

    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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