25 research outputs found

    Atlantic Water Circulation and Properties Northwest of Svalbard During Anomalous Southerly Winds

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    Atlantic Water (AW), the main source of heat and salt for the Arctic Ocean, undergoes large transformations (cooling and freshening) north of Svalbard as it flows near the surface above the Yermak Plateau (YP). In September 2017, a SeaExplorer ocean glider deployed in the West Spitsbergen Current (WSC) and recovered north of Svalbard documented the circulation and properties of the AW crossing the YP. The glider sampled the different branches of the AW flowing into the Arctic around the YP: the WSC, the Svalbard Branch (SB), the Yermak Pass Branch, and the Yermak Branch. Unusual southerly winds prevailed in summer 2017 impacting AW circulation in the region. Cold and fresh lenses of shelf-origin waters detached from the slope in the WSC to reach their density level below the core of the AW. This resulted in cooling and freshening of the AW inflow from below. The eastward current associated with the SB was found to be weak at its usual location above the 400 m isobath, likely the result of the adjustment of the flow influenced by anomalous southerly wind conditions.publishedVersio

    Recent exposure to ultrafine particles in school children alters miR-222 expression in the extracellular fraction of saliva

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    Background: Ultrafine particles (< 100 nm) are ubiquitous present in the air and may contribute to adverse cardiovascular effects. Exposure to air pollutants can alter miRNA expression, which can affect downstream signaling pathways. miRNAs are present both in the intracellular and extracellular environment. In adults, miR-222 and miR-146a were identified as associated with particulate matter exposure. However, there is little evidence of molecular effects of ambient air pollution in children. This study examined whether exposure to fine and ultrafine particulate matter (PM) is associated with changes in the extracellular content of miR-222 and miR-146a of children. Methods: Saliva was collected from 80 children at two different time points, circa 11 weeks apart and stabilized for RNA preservation. The extracellular fraction of saliva was obtained by means of differential centrifugation and ultracentrifugation. Expression levels of miR-222 and miR-146a were profiled by qPCR. We regressed the extracellular miRNA expression against recent exposure to ultrafine and fine particles measured at the school site using mixed models, while accounting for sex, age, BMI, passive smoking, maternal education, hours of television use, time of the day and day of the week. Results: Exposure to ultrafine particles (UFP) at the school site was positively associated with miR-222 expression in the extracellular fraction in saliva. For each IQR increase in particles in the class room (+8504 particles/cm(3)) or playground (+ 28776 particles/cm(3)), miR-222 was, respectively 23.5 % (95 % CI: 3.5 %-41.1 %; p = 0.021) or 29.9 % (95 % CI: 10.6 %-49.1 %; p = 0.0027) higher. No associations were found between miR-146a and recent exposure to fine and ultrafine particles. Conclusions: Our results suggest a possible epigenetic mechanism via which cells respond rapidly to small particles, as exemplified by miR-222 changes in the extracellular fraction of saliva

    Deep learning-based phenotyping reclassifies combined hepatocellular-cholangiocarcinoma.

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    Primary liver cancer arises either from hepatocytic or biliary lineage cells, giving rise to hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (ICCA). Combined hepatocellular- cholangiocarcinomas (cHCC-CCA) exhibit equivocal or mixed features of both, causing diagnostic uncertainty and difficulty in determining proper management. Here, we perform a comprehensive deep learning-based phenotyping of multiple cohorts of patients. We show that deep learning can reproduce the diagnosis of HCC vs. CCA with a high performance. We analyze a series of 405 cHCC-CCA patients and demonstrate that the model can reclassify the tumors as HCC or ICCA, and that the predictions are consistent with clinical outcomes, genetic alterations and in situ spatial gene expression profiling. This type of approach could improve treatment decisions and ultimately clinical outcome for patients with rare and biphenotypic cancers such as cHCC-CCA

    Under-Ice Phytoplankton Blooms in the Central Arctic Ocean: Insights From the First Biogeochemical IAOOS Platform Drift in 2017

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    In April 2017, the first Ice Atmosphere Arctic Ocean Observing System (IAOOS) platform equipped with biogeochemical sensors was deployed near the North Pole. Over the next 8 months it meandered southward with the ice, collecting measurements in the upper 250 m of Amundsen Basin, the Gakkel Ridge, Nansen Basin, and Fram Strait. Two distinct periods of primary production were encountered. The first bloom developed in the mixed layer in Amundsen Basin in May, reaching maximum chlorophyll a concentrations on the order of ~ 0.5 mg m−3 by the end of June. This bloom occurred earlier in the year than any other recorded bloom in Amundsen Basin, despite very limited under-ice light due to a thick layer of snow. The second bloom, encountered in Nansen Basin in August, was significantly larger (mean profile maximum chlorophyll a was 1.45 mg m−3). Examinations of the optical community index and colored dissolved organic matter concentrations suggest that the spring bloom consisted of small phytoplankton which may have been mixotrophic, while the summer bloom contained a greater diversity of planktonic size classes. The data set demonstrates the heterogeneity of Arctic under-ice primary production, and is a valuable resource for validating coupled Earth System models

    Recent versus chronic exposure to particulate matter air pollution in association with neurobehavioral performance in a panel study of primary schoolchildren

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    Children's neuropsychological abilities are in a developmental stage. Recent air pollution exposure and neurobehavioral performance are scarcely studied. In a panel study, we repeatedly administered to each child the following neurobehavioral tests: Stroop Test (selective attention) and Continuous Performance Test (sustained attention), Digit Span Forward and Backward Tests (short-term memory), and Digit-Symbol and Pattern Comparison Tests (visual information processing speed). At school, recent inside classroom particulate matter ≤2.5 or 10μm exposure (PM2.5, PM10) was monitored on each examination day. At the child's residence, recent (same day up to 2days before) and chronic (365days before examination) exposures to PM2.5, PM10 and black carbon (BC) were modeled. Repeated neurobehavioral test performances (n=894) of the children (n=310) reflected slower Stroop Test (p=0.05) and Digit-Symbol Test (p=0.01) performances with increasing recent inside classroom PM2.5 exposure. An interquartile range (IQR) increment in recent residential outdoor PM2.5 exposure was associated with an increase in average latency of 0.087s (SE: ±0.034; p=0.01) in the Pattern Comparison Test. Regarding chronic exposure at residence, an IQR increment of PM2.5 exposure was associated with slower performances in the Continuous Performance (9.45±3.47msec; p=0.007) and Stroop Tests (59.9±26.5msec; p=0.02). Similar results were obtained for PM10 exposure. In essence, we showed differential neurobehavioral changes robustly and adversely associated with recent or chronic ambient exposure to PM air pollution at residence, i.e., with recent exposure for visual information processing speed (Pattern Comparison Test) and with chronic exposure for sustained and selective attention.status: publishe
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