61 research outputs found

    Anomalous Transport Properties in BiS2-based Superconductors LnO1−xFxBiS2 (Ln = Nd, La-Sm)

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    We report the electronic properties of the layered bismuth-based sulfide superconductors NdO1−xFxBiS2 (x = 0.25, 0.4, and 0.5) and La1−ySmyO0.5F0.5BiS2 (y = 0.1–0.7), which have been studied by investigation of their transport properties and X-ray diffraction. In the lightly carrier-doped NdO1−xFxBiS2 (x = 0.25 and 0.4) and La1−ySmyO0.5F0.5BiS2 (y = 0.3 and 0.4), the resistivity and Hall coefficient exhibit anomalous temperature dependences below TCDW ∼ 130 and 200 K, respectively, suggesting the formation of an energy gap on the Fermi surface associated with charge-density wave (CDW). In NdO1−xFxBiS2 (x = 0.25), the bond angles and bond lengths of the Bi–S pentahedron change their temperature dependences below ∼200 K, suggesting that a lattice instability related to the Bi–S pentahedron exists below ∼200 K, which is much higher than TCDW. These results indicate that the lattice instability of the Bi–S pentahedron can trigger a CDW transition in the low-carrier region of BiS2 superconductors

    Helicobacter pylori Evolution: Lineage- Specific Adaptations in Homologs of Eukaryotic Sel1-Like Genes

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    Geographic partitioning is postulated to foster divergence of Helicobacter pylori populations as an adaptive response to local differences in predominant host physiology. H. pylori's ability to establish persistent infection despite host inflammatory responses likely involves active management of host defenses using bacterial proteins that may themselves be targets for adaptive evolution. Sequenced H. pylori genomes encode a family of eight or nine secreted proteins containing repeat motifs that are characteristic of the eukaryotic Sel1 regulatory protein, whereas the related Campylobacter and Wolinella genomes each contain only one or two such “Sel1-like repeat” (SLR) genes (“slr genes”). Signatures of positive selection (ratio of nonsynonymous to synonymous mutations, dN/dS = ω > 1) were evident in the evolutionary history of H. pylori slr gene family expansion. Sequence analysis of six of these slr genes (hp0160, hp0211, hp0235, hp0519, hp0628, and hp1117) from representative East Asian, European, and African H. pylori strains revealed that all but hp0628 had undergone positive selection, with different amino acids often selected in different regions. Most striking was a divergence of Japanese and Korean alleles of hp0519, with Japanese alleles having undergone particularly strong positive selection (ωJ > 25), whereas alleles of other genes from these populations were intermingled. Homology-based structural modeling localized most residues under positive selection to SLR protein surfaces. Rapid evolution of certain slr genes in specific H. pylori lineages suggests a model of adaptive change driven by selection for fine-tuning of host responses, and facilitated by geographic isolation. Characterization of such local adaptations should help elucidate how H. pylori manages persistent infection, and potentially lead to interventions tailored to diverse human populations

    Omentin Prevents Myocardial Ischemic Injury Through AMP-Activated Protein Kinase- and Akt-Dependent Mechanisms

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    ObjectivesThis study examined the impact of omentin on myocardial injury in a mouse model of ischemia/reperfusion (I/R) and explored its underlying mechanisms.BackgroundObesity is a major risk factor for ischemic heart disease. Omentin is a circulating adipokine that is down-regulated by obesity.MethodsIn patients who underwent successful reperfusion treatment after acute myocardial infarction, cardiac function and perfusion defect were assessed by using scintigraphic images. Mice were subjected to myocardial ischemia followed by reperfusion.ResultsThis study found that high levels of plasma omentin were associated with improvement of heart damage and function after reperfusion therapy in patients with acute myocardial infarction. Systemic administration of human omentin to mice led to a reduction in myocardial infarct size and apoptosis after I/R, which was accompanied by enhanced phosphorylation of AMP-activated protein kinase (AMPK) and Akt in the ischemic heart. Fat-specific overexpression of human omentin also resulted in reduction of infarct size after I/R. Blockade of AMPK or Akt activity reversed omentin-induced inhibition of myocardial ischemic damage and apoptosis in mice. In cultured cardiomyocytes, omentin suppressed hypoxia/reoxygenation-induced apoptosis, which was blocked by inactivation of AMPK or Akt.ConclusionsOur data indicate that omentin functions as an adipokine that ameliorates acute ischemic injury in the heart by suppressing myocyte apoptosis through both AMPK- and Akt-dependent mechanisms

    A model relating transpiration for Japanese cedar and cypress plantations with stand structure

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    Previous studies have revealed that changes in forest structure due to management (e.g., thinning, aging, and clearcutting) could affect the forest water balance. However, there are unexplained variability in changes in the annual water balance with changing structure among different sites. This is the case even when analyzing data for specific species/regions. For a more advanced and process-based understanding of changes in the water balance with changing forest structure, we examined transpiration (E) observed using the sap-flux method for 14 Japanese cedar and cypress plantations with various structure (e.g., stem density and diameter) in Japan and surrounding areas and developed a model relating E with structural parameters. We expressed E using the simplified Penman–Monteith equation and modeled canopy conductance (G[c]) as a product of reference G[c] (G[cref]) when vapor pressure deficit is 1.0 kPa and functions expressing the responses of G[c] to meteorological factors. We determined G[cref] and parameters of the functions for the sites separately. E observed for the 14 sites was not reproduced well by the model when using mean values of G[cref] and the parameters among the sites. However, E observed for the sites was reproduced well when using G[cref] determined for each site and mean values of the parameters of the functions among the sites, similar to the case when using G[cref] and the parameters of the functions determined for each site. These results suggest that considering variations in G[cref] among the sites was important to reproduce variations in E, but considering variations in the parameters of the functions was not. Our analysis revealed that G[cref] linearly related with the sapwood area on a stand scale (A) and that Alinearly related with stem density (N) and powers of the mean stem diameter (d[m]). Thus, we proposed a model relating E with A (or N and d[m]), where G[cref] was calculated from A (or N and d[m]) and the parameters of the functions were assumed to be the mean values among the sites. This model estimates changes in Ewith changing structure from commonly available data (N and d[m]), and therefore helps improve our understanding of the underlying processes of the changes in the water balance for Japanese cedar and cypress plantations

    The Current Status of SME Financing under the Financial Crisis: A summary of the Survey on the Status of Transactions between Businesses and Financial Institutions (Feb. 2008) and the Survey on the Status of Transactions between Businesses and Financial Institutions following the Financial Crisis (Feb. 2009). (Japanese)

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    This paper summarizes the results of two questionnaires presented to small and medium size enterprises (SMEs) by RIETI in February 2008 and February 2009. Given the limited data on SMEs, the purpose of the questionnaires is to understand the current status of financing for SMEs facing this serious economic recession, triggered by the financial crisis. The Survey on the Status of Transactions between Businesses and Financial Institutions conducted in February 2008, was sent to 17,018 companies nationwide, with SMEs being the main target, and of those recipients 6,124 companies or 36.0% responded. This survey, which was designed to explain the structural characteristics of SME financing, illustrated terms and conditions such as accounts payable and bills payable for inter-firm credit, differences in the roles of major lending financial institutions including main banks, and the impact of changes in the credit guarantee system in recent years. Regarding the Survey on the Status of Transactions between Businesses and Financial Institutions following the Financial Crisis conducted in February 2009, RIETI targeted 5,979 of the companies who responded to the 2008 survey and of those companies 4,103 or 68.6% responded. The survey was conducted to understand how the relationships between companies and financial institutions and customers and suppliers changed, and what measures SMEs took to address these changes, in light of the fact that the cash management of SMEs has been extremely difficult since last autumn, when the global credit crunch set in. Although the surveys were not identical, some of the same questions were asked in both surveys. The answers to these questions were then compared to see how conditions had changed and to understand which areas of SME financing had become more difficult.

    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

    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

    Volumetric analysis of mandibular lesions with SPECT/CT : a pilot clinical study of maximum standardized uptake value

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    Purpose: This study was designed to investigate mandibular lesions using volumetric analysis with bone single-photon emission computed tomography/computed tomography (SPECT/CT). Material and methods: Eight patients with mandibular lesions underwent SPECT/CT scan acquisition 4 hours after injection of Tc-99m hydroxymethylene diphosphonate (HMDP). Regarding volumetric analysis, maximum standardized uptake value (SUV) was obtained using software and a workstation (Q.Volumetrix MI and GEniE-Xeleris 4 DR, respectively). The localization and size of the volume of interest (VOI) can be drawn over the lesion, mesial, distal, and opposite side as normal using the CT, SPECT, and SPECT/CT transaxials, coronals, and sagittals as the anatomical reference. Q.Volumetrix MI can analyse SUV of lesions by organ segmentation using optional pan and zoom imaging. Then, the dosimetry software provided multiple quantitative data for a given VOI. Statistical analyses for the maximum SUV were performed by Mann-Whitney U test. A p-value lower than 0.05 was considered as statistically significant. Results: Maximum SUVs for medication-related osteonecrosis of the jaw (n = 4, 25.4 ± 4.9), chronic osteomyelitis (n = 3, 14.6 ± 3.1), and squamous cell carcinoma (n = 1, 31.7) were significantly higher than those of the opposite side as normal mandible (3.8 ± 0.7, 4.6 ± 1.8, and 7.4, respectively; p = 0.000). Conclusions: Volumetric analysis with SPECT/CT could be useful for the evaluation of mandibular lesions, such as detecting and surgical planning

    Kairos Chat: a novel text-based chat system that has multiple streams of time

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    In this paper we propose a novel chat system named"Kairos Chat" that has multiple streams of time whosevelocities are different. A pilot study shows that usersspontaneously use the different streams for differenttypes of messages without any concrete instructions onhow to use the streams
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