64 research outputs found

    Experimental results on the formation of hard compacted snow in Rikubetsu in northern Japan: A first step toward the construction of a compacted-snow runway on the Antarctic ice sheet

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    This paper describes the experimental methods and results on the formation of hard compacted snow in Rikubetsu in northern Japan during the winter of 1999. This basic research was the first step towards the construction of a compacted-snow runway on the Antarctic ice sheet. In Rikubetsu, we constructed three test fields(20m in length, 7m in width, and 0.4-1.0m in thickness) on compacted basal snow(approximately 0.05m in thickness). First, 0.1-0.35-m-thick layers of snow were deposited on the basal snow of the fields using a rotary snowplow. Next, the surface snow was smoothed using an excavator. Finally, the snow layers were compacted four times using a bulldozer. This entire process was repeated three to four times in order to construct 0.4-1.0-m-thick test fields. The ram hardness, snow density, and snow structure of these fields were investigated. A comparison with the criteria established by a U.S. scientist for a large aircraft-such as the C-130(Abele, 1990)-revealed that if snow in the form of three 0.2-0.25-m-thick layers is compacted four times by a bulldozer, it is sufficiently hard to serve as a runway at H68(69°11\u279″S, 41°03\u2734″E, 1204m a.s.l.) for a wheeled C-130. The Japanese Antarctic Research Expedition plans to conduct a feasibility study on the construction of the hard com-pacted-snow runway at this location

    High-Resolution Imaging of Patients with Bietti Crystalline Dystrophy with CYP4V2

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    The purpose of this study was to determine the retinal morphology of eyes with Bietti crystalline dystrophy (BCD) associated with a CYP4V2 mutation using high-resolution imaging techniques. Three subjects with BCD underwent detailed ophthalmic examinations. High-resolution fundus images were obtained with an adaptive optics (AO) fundus camera. A common homozygous mutation was detected in the three patients. Funduscopic examination of the three patients revealed the presence of crystalline deposits in the retina, and all of the crystalline deposits were also detected in the infrared (IR) images. The crystals observed in the IR images were seen as bright reflective plaques located on the RPE layer in the SD-OCT images. The clusters of hyperreflective signals in the AO images corresponded to the crystals in the IR images. High-magnification AO images revealed that the clusters of hyperreflective signals consisted of circular spots that are similar to the signals of cone photoreceptors. Most of these circular spots were detected in healthy areas in the FAF images. There is a possibility that circular spots observed by AO are residual cone photoreceptors located over the crystals

    Inferring cluster-based networks from differently stimulated multiple time-course gene expression data

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    Motivation: Clustering and gene network inference often help to predict the biological functions of gene subsets. Recently, researchers have accumulated a large amount of time-course transcriptome data collected under different treatment conditions to understand the physiological states of cells in response to extracellular stimuli and to identify drug-responsive genes. Although a variety of statistical methods for clustering and inferring gene networks from expression profiles have been proposed, most of these are not tailored to simultaneously treat expression data collected under multiple stimulation conditions

    DOCK2 is involved in the host genetics and biology of severe COVID-19

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    「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target

    The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force

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    「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection
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