98 research outputs found

    Research on mitigation of the interaction of sea turtle with pelagic longline fishery in the western North Pacific

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    December 13-14, 2006, Siam City Hotel, Bangkok, ThailandWe conducted shallow-set longline fishing operations on a research vessel in the western North Pacific, May-July, 2002-2004. We investigated sea turtle interaction with a pelagic longline fishery and preliminarily examined the potential gear modifications (bait and hook types) for reducing sea turtle bycatch or mortality. A total of 54 loggerhead sea turtle Caretta caretta were caught in 76 operations (about 74, 000 hooks), which were all alive. The mean straight carapace length was 67 cm (range: 52 - 82 cm); this suggested most of loggerhead sea turtles caught in this area were sub-adult. Loggerhead sea turtle catches ranged from 19.1 to 24.5 °C in sea surface temperature, which were concentrated in warm water masses in the Kuroshio extension. The Loggerhead sea turtle catch was more frequently observed on hooks hauled after sunrise. For bait type, the catches by mackerel bait were fewer than those by squid bait. In the circle hook trial in 2003, the deep-hooking rates (proportion of deep-hooking (at esophagus or pharynx) to total in numbers) on squid bait were 0.41 and 0.23 in 3.8 sun conventional tuna hook (n = 22) and 3.8 sun Tankichi type circle hook (which had similar size to 3.8 sun conventional tuna hook) (n = 13), respectively, but the difference was not significant (P > 0.05, extended Fisher’s exact test). In 2004 the large 18/0 circle hooks (which had a larger size, compared to 3.8 sun tuna hook) were tested, but its effect was not clarified due to very small catch numbers. Following these researches, we have been conducting sea turtle mitigation studies, with evaluation of their impacts on target and other non-target species catches

    Lift and thrust generation by a butterfly-like flapping wing-body model: immersed boundary-lattice Boltzmann simulations

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    The flapping flight of tiny insects such as flies or larger insects such as butterflies is of fundamental interest not only in biology itself but also in its practical use for the development of micro air vehicles (MAVs). It is known that a butterfly flaps downward for generating the lift force and backward for generating the thrust force. In this study, we consider a simple butterfly-like flapping wing body model in which the body is a thin rod and the rectangular rigid wings flap in a simple motion. We investigate lift and thrust generation of the model by using the immersed boundary lattice Boltzmann method. First, we compute the lift and thrust forces when the body of the model is fixed for Reynolds numbers in the range of 50-1000. In addition, we estimate the supportable mass for each Reynolds number from the computed lift force. Second, we simulate free flights when the body can only move translationally. It is found that the expected supportable mass can be supported even in the free flight except when the mass of the body relative to the mass of the fluid is too small, and the wing body model with the mass of actual insects can go upward against the gravity. Finally, we simulate free flights when the body can move translationally and rotationally. It is found that the body has a large pitch motion and consequently gets off-balance. Then, we discuss a way to control the pitching angle by flexing the body of the wing body model.ArticleJOURNAL OF FLUID MECHANICS. 767:659-695 (2015)journal articl

    Tailoring Stresses in Piezoresistive Microcantilevers for Enhanced Surface Stress Sensing: Insights from Topology Optimization

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    In assessing piezoresistive microcantilever sensitivity for surface stress sensing, the key is its capacity to translate surface stress into changes in resistance. This change hinges on the interplay between stresses and piezoresistivity. Traditional optimization has been constrained by rudimentary 1D models, overlooking potentially superior designs. Addressing this, we employed topology optimization to optimize Si(100) microcantilevers with a p-type piezoresistor. This led to optimized designs with up to 30% enhanced sensitivity over conventional designs. A recurrent "double-cantilever" configuration emerged, which optimizes longitudinal stress and reduces transverse stress at the piezoresistor, resulting in enhanced sensitivity. We developed a simplified model to analyze stress distributions in these designs. By adjusting geometrical features in this model, we identified ideal parameter combinations for optimal stress distribution. Contrary to conventional designs favoring short cantilevers, our findings redefine efficient surface stress sensing, paving the way for innovative sensor designs beyond the conventional rectangular cantilevers.Comment: 18 pages, 6 figure

    Nesting and post-nesting studies of loggerhead turtles (Caretta caretta) at Omaezaki, Japan

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    Organized by Graduate School of Informatics, Kyoto University ; JSPS Bangkok Liaison Office ; Japanese Society of Bio-logging Science ; Informatics Research Center for Development of Knowledge Society InfrastructureDecember 13-15, 2004, Imperial Tara Hotel, Bangkok, ThailandNesting biology, measurement of body size and mitochondrial (mt) DNA haplotypes of loggerhead turtle, Caretta caretta at Omaezaki Beach, Japan were investigated by collecting data and samples during night observations from 6 July to 6 August 2004. In addition, seven post-nesting females, which nested during this observation period, were tracked by satellite telemetry. A total of 33 females were identified in this observation period. Seven females nested twice, with a mean inter-nesting interval of 18.0 days. Even though our observations did not cover the entire nesting beach and period, the frequency of nesting was estimated at three, using a calculation based on the total number of nests at this beach in this nesting season. The range of straight carapace length (SCL) was from 65.8 to 91.6 cm, and the mean (±SD) size was 81.5±5.83 cm. The SCL of females at Omaezaki Beach is significantly lower than at other nesting sites in Japan based on calculation of 90% confidence intervals for mean SCLs. Two haplotypes were detected among 33 females using mitochondrial (mt) DNA analysis. Composition of these two haplotypes of nesting females at Omaezaki Beach was similar to nesting females at other nesting beaches in Japan. Post-nesting feeding grounds of seven loggerhead turtles released from Omaezaki consist of two areas, the northwestern North Pacific and the East China Sea. It is confirmed that nesting females at Omaezaki Beach were from the two groups using the different post-nesting feeding grounds and these two groups can be distinguished by their body size criterion of 85 cm. If different factors impact females in each feeding ground, monitoring the number of females and the composition of body size can be useful in assessing the impact to females

    水溶性フラーレンを用いた薬剤およびsiRNAのin vitro, in vivo輸送

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    学位の種別:課程博士University of Tokyo(東京大学

    Point-of-Care Lung Ultrasound for COVID-19: Findings and Prognostic Implications From 105 Consecutive Patients

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    Background: The prognostic value of point-of-care lung ultrasound has not been evaluated in a large cohort of patients with COVID-19 admitted to general medicine ward in the United States. The aim of this study was to describe lung ultrasound findings and their prognostic value in patients with COVID-19 admitted to internal medicine ward. Method: This prospective observational study consecutively enrolled 105 hospitalized participants with COVID-19 at 2 tertiary care centers. Ultrasound was performed in 12 lung zones within 24 hours of admission. Findings were assessed relative to 4 outcomes: intensive care unit (ICU) need, need for intensive respiratory support, length of stay, and death. Results: We detected abnormalities in 92% (97/105) of participants. The common findings were confluent B-lines (92%), non-homogenous pleural lines (78%), and consolidations (54%). Large confluent B-lines, consolidations, bilateral involvement, and any abnormality in ≥ 6 areas were associated with a longer hospitalization and need for intensive respiratory support. Large confluent B-lines and bilateral involvement were also associated with ICU stay. A total lung ultrasound score \u3c5 had a negative predictive value of 100% for the need of intensive respiratory support. A higher total lung ultrasound score was associated with ICU need (median total 18 in the ICU group vs. 11 non-ICU, p = 0.004), a hospitalization ≥ 9d (15 vs 10, p = 0.016) and need for intensive respiratory support (18 vs. 8.5, P \u3c 0.001). Conclusions: Most patients hospitalized with COVID-19 had lung ultrasound abnormalities on admission and a higher lung ultrasound score was associated with worse clinical outcomes except death. A low total lung ultrasound score (\u3c5) had a negative predictive value of 100% for the need of intensive respiratory support. Point-of-care ultrasound can aid in the risk stratification for patients with COVID-19 admitted to general wards

    A non-carboxylating pentose bisphosphate pathway in halophilic archaea

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    Bacteria and Eucarya utilize the non-oxidative pentose phosphate pathway to direct the ribose moieties of nucleosides to central carbon metabolism. Many archaea do not possess this pathway, and instead, Thermococcales utilize a pentose bisphosphate pathway involving ribose-1, 5-bisphosphate (R15P) isomerase and ribulose-1, 5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco). Intriguingly, multiple genomes from halophilic archaea seem only to harbor R15P isomerase, and do not harbor Rubisco. In this study, we identify a previously unrecognized nucleoside degradation pathway in halophilic archaea, composed of guanosine phosphorylase, ATP-dependent ribose-1-phosphate kinase, R15P isomerase, RuBP phosphatase, ribulose-1-phosphate aldolase, and glycolaldehyde reductase. The pathway converts the ribose moiety of guanosine to dihydroxyacetone phosphate and ethylene glycol. Although the metabolic route from guanosine to RuBP via R15P is similar to that of the pentose bisphosphate pathway in Thermococcales, the downstream route does not utilize Rubisco and is unique to halophilic archaea

    e+eH+He^+e^-\to H^+H^- signals at LEP2 energies in the Minimal Supersymmetric Standard Model

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    In this paper we compare H+HH^+H^- and W+WW^+W^- into four-fermion production at centre-of-mass energies typical of LEP2 and somewhat larger. The theoretical framework considered is the Minimal Supersymmetric Standard Model. The interest in exploiting the e+ee^+e^- CERN collider at values of s\sqrt s greater than 192 GeV could come from the discovery of Supersymmetric signals during runs at lower energy. If these indicate that a charged Higgs boson exists in the mass range \MH\approx95-105 GeV, then a few years of running at s=205215\sqrt s=205-215 GeV and nominal luminosity could make the detection of such scalars feasible, in the purely leptonic channel τνττντ\tau\nu_\tau\tau\nu_\tau and, for small \tb's, also in the semi-hadronic(leptonic) one jjτντ{jj}\tau\nu_\tau. Charged Higgs bosons of the above nature cannot be produced by the beam energies approved at present for LEP2. However, if runs beyond the so-called `192 GeV cryogenic limit' will be approved by the CERN Council, our selection procedure will enable us to establish the presence, or otherwise, of charged Higgs bosons in the mentioned mass rangeComment: 30 pages, latex, epsfig, 12 postscript figures, complete paper available at ftp://axpa.hep.phy.cam.ac.uk/stefano/cavendish_9615 and at http://www.hep.phy.cam.ac.uk/theory/papers

    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
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