38 research outputs found

    Ground state and finite temperature behavior of 1/4-filled band zigzag ladders

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    We consider the simplest example of lattice frustration in the 1/4-filled band, a one-dimensional chain with next-nearest neighbor interactions. For this zigzag ladder with electron-electron as well as electron-phonon interactions we present numerical results for ground state as well as thermodynamic properties. In this system the ground state bond distortion pattern is independent of electron-electron interaction strength. The spin gap in the ground state of the zigzag ladder increases with the degree of frustration. Unlike in one-dimension, where the spin-gap and charge ordering transitions can be distinct, we show that in the ladder they occur simultaneously. We discuss spin gap and charge ordering transitions in 1/4-filled materials with one, two, or three dimensional crystal structures. We show empirically that regardless of dimensionality the occurrence of simultaneous or distinct charge and magnetic transitions can be correlated with the ground state bond distortion pattern.Comment: 12 pages, 8 eps figure

    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

    An adult cystidicolid nematode (Nematoda: Cystidicolidae) from the subcutaneous tissue around the eye of percupinefish, Diodon nichthemerus Cuvier

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    Three adult nematode specimens, all ovigerous females belonging to the family Cystidicolidae Skryabin, 1946, were found for the first time in the subcutaneous tissue around the eye of the captive porcupinefish Diodon nichthemerus Cuvier at a public aquarium in Osaka, Japan. Because no male was available, these could not be identified to the genus and species. This case highlights the risk of parasitism in aquaculture puffer fish, as these may ingest small shrimp, which probably act as intermediate hosts for the nematode

    Photoinduced radical generation and trapping by acrylonitrile of N-Boc secondary amine and N-Boc N-methyl α-amino acid ester at α-position using two-molecule photoredox catalysts

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    The photoreaction of an N-Boc secondary amine and N-Boc N-methyl α-amino acid ester with acrylonitrile using inexpensive two-molecule photoredox catalysts results in the production of α-alkylated amine through the generation of an α-carbamy radical under mild conditions. In particular, this mothed leads to a regioselective modification of N-Boc N-methyl α-amino acid ester with the retention of α-chirality through the generation of the less stable primary α-carbamyl radical

    脱気した水による大豆種子の膨潤および脂質成分への影響

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    Changes in weights, moisture contents, hardness and lipid components of soybeans soaked in deaerated (dissolved oxygen concentration, 0.5ppm) and distilled water for 0.5 to 24 hours at 20℃ were examined. Swelling of 110 to 120% of soybeans was obtained 10 and 15 to 16 hours in deaerated and distilled water, respectively. This means that swelling time using deaerated water was about two-thirds of that of distilled water. Changes in weights and hardness of soybeans during soaking showed the same tendency to that of moisture contents in both water. The average lipid contents and its composition were not significantly different between two kinds of water. The proportion of phospholipids of soybeans soaked in deaerated water for up to 12 hours was greater than that soaked in distilled water, whereas there were no differences in the amounts of free fatty acids and fatty acid compositions between two kinds of water. Among peroxide value (POV), carbonyl value (COV) and 2-thiobarbituric acid value (TBAV), POV showed a significant difference between deaerated and distilled water (p<0.05). These results show that lipid oxidation rather than hydrolysis occurred during swelling process of soybeans at 20℃. The changes of lipids were less in deaerated water compared with those in distilled water
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