THREE-DIMENSIONAL FLOW FIELD AND LEG MOTION DURING UNDULATORY UNDERWATER SWIMMING

This study described swimmers’ leg motions and the three-dimensional flow field around their legs during undulatory underwater swimming (UUS). We used the particle image velocimetry (PIV) method and a three-dimensional motion capture system. Seven male swimmers participated and we acquired EMG data of one male swimmer during UUS after the previous experiment. After the downward kick motion that includes the legs’ lateral rotation and the ankles’ dorsal flexion, water’s backward momentum was observed. During the upward kick motion, backward flow velocity decreased, but flow occurred in a vertical, upward direction. This suggested that UUS could demonstrate great propulsion power by generating jet flow through the downward kick motion that might be assisted by upstream flow from the upward kick motion

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

「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

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

「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

Katsura

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Improved near-infrared sensitivity of a back-side illuminated image sensor with a metal reflector

To improve the near-infrared sensitivity of an image sensor that has a conventional pixel structure, we made use of the metal wiring layer as a reflector in addition to the method of back-side illumination from the etched back surface of the sensor. We f

Microfluidic biosensor for the detection of DNA by fluorescence enhancement and the following streptavidin detection by fluorescence quenching

We reported an optical DNA/protein microfluidic sensor which consists of single stranded (ss) DNA-Cy3 probes on gold surface and simple line-shape microfluidic channel. These ssDNA-Cy3 probes with random sequence in bulk solution or on gold surface exhibits fluorescence enhancement after binding with complementary ssDNA (cssDNA) targets. Particularly it did not require complicated design or hairpin-like stem-loop conformation, which made it easier to be made and applied in analytes detection by fluorescence switching techniques. Using ssDNA-cy3 probes attached on gold surface in a microfluidic channel, strong fluorescence enhancement was measured by ssDNA with cssDNA binding or ssDNA with cssDNA-biotin binding. The following introduction of streptavidin resulted in fluorescence quenching (fluorescence decrease) because of the binding of hybridized DNA-biotin with streptavidin. This sensor showed strong affinity and high sensitivity toward the streptavidin, the minimum detectable concentration for streptavidin was 1 pM, equating to an absolute detection limit of 60 amol in this microfluidic channel. Microfluidic channel height and flow rate is optimized to increase surface reaction efficiency and fluorescence switching efficiency. In contrast to previously reported optical molecular beacon approach, this sensor can be used not only for the detection of cssDNA target, but also for the detection of streptavidin. This microfluidic sensor offers the promise of analyzing kinds of molecular targets or immunoreactions

Improved near-infrared sensitivity of a back-side illuminated image sensor with a metal reflector

To improve the near-infrared sensitivity of an image sensor that has a conventional pixel structure, we made use of the metal wiring layer as a reflector in addition to the method of back-side illumination from the etched back surface of the sensor. We f