113 research outputs found

    On the Flux Vacua in F-theory Compactifications

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    We study moduli stabilization of the F-theory compactified on an elliptically fibered Calabi-Yau fourfold. Our setup is based on the mirror symmetry framework including brane deformations. The complex structure moduli dependence of the resulting 4D N=1 effective theory is determined by the associated fourfold period integrals. By turning on appropriate G-fluxes, we explicitly demonstrate that all the complex structure moduli fields can be stabilized around the large complex structure point of the F-theory fourfold.Comment: 5 pages, v2: published versio

    Three-body forces and the limit of oxygen isotopes

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    The limit of neutron-rich nuclei, the neutron drip-line, evolves regularly from light to medium-mass nuclei except for a striking anomaly in the oxygen isotopes. This anomaly is not reproduced in shell-model calculations derived from microscopic two-nucleon forces. Here, we present the first microscopic explanation of the oxygen anomaly based on three-nucleon forces that have been established in few-body systems. This leads to repulsive contributions to the interactions among excess neutrons that change the location of the neutron drip-line from 28^{28}O to the experimentally observed 24^{24}O. Since the mechanism is robust and general, our findings impact the prediction of the most neutron-rich nuclei and the synthesis of heavy elements in neutron-rich environments.Comment: 4 pages, 4 figures, to be published in PR

    Burnout of Healthcare Workers amid the COVID-19 Pandemic: A Japanese Cross-Sectional Survey

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    The coronavirus disease 2019 (COVID-19) global pandemic has drastically changed how we live and work. Amid the prolonged pandemic, burnout of the frontline healthcare professionals has become a significant concern. We conducted a cross-sectional survey study to provide data about the relationship between the COVID-19 pandemic and the prevalence of burnout in healthcare professionals in Japan. Healthcare workers in a single Japanese national university hospital participated in the survey, including basic demographics, whether a participant engaged in care of COVID-19 patients in the past 2 weeks and the Maslach Burnout Inventory. Of those, 25.4% fully answered the survey; 33.3% were doctors and 63.6% were nurses, and 36.3% engaged in care of COVID-19 patients in the past 2 weeks. Compared to those belonging to General Medicine, those in Emergency Intensive Care Unit were at higher risk of burnout (odds ratio (OR), 6.7; 95% CI, 1.1-42.1; p = 0.031). Of those who engaged in care of COVID-19 patients, 50% reported burnout while 6.1% did not (OR 8.5, 95% CI; 1.3-54.1; p = 0.014). The burnout of healthcare workers is a significant concern amid the pandemic, which needs to be addressed for sustainable healthcare delivery

    A human transporter protein that mediates the final excretion step for toxic organic cations

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    In mammals, toxic electrolytes of endogenous and exogenous origin are excreted through the urine and bile. Before excretion, these compounds cross numerous cellular membranes in a transporter-mediated manner. However, the protein transporters involved in the final excretion step are poorly understood. Here, we show that MATE1, a human and mouse orthologue of the multidrug and toxin extrusion (MATE) family conferring multidrug resistance on bacteria, is primarily expressed in the kidney and liver, where it is localized to the luminal membranes of the urinary tubules and bile canaliculi. When expressed in HEK293 cells, MATE1 mediates H+-coupled electroneutral exchange of tetraethylammonium (TEA) and 1-methyl-4-phenylpyridinium (MPP). Its substrate specificity is similar to those of renal and hepatic H+-coupled organic cations (OCs) export. Thus, MATE1 appears to be the long searched for polyspecific OC exporter that directly transports toxic OCs into urine and bile.</p

    Burnout of Healthcare Workers Amid the COVID-19 Pandemic: A Follow-Up Study

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    The coronavirus disease 2019 (COVID-19) pandemic has posed a significant challenge to the modern healthcare system and led to increased burnout among healthcare workers (HCWs). We previously reported that HCWs who engaged in COVID-19 patient care had a significantly higher prevalence of burnout (50.0%) than those who did not in November 2020 (period 1). We performed follow-up surveys in HCWs in a Japanese national university hospital, including basic demographics, whether a participant engaged in care of COVID-19 patients in the past 2 weeks, and the Maslach Burnout Inventory in February 2021 (period 2) and May 2021 (period 3). Periods 1 and 3 were amid the surges of COVID-19 cases, and period 2 was a post-surge period with a comparatively small number of COVID-19 patients requiring hospitalization. Response rates to the surveys were 33/130 (25.4%) in period 1, 36/130 (27.7%) in period 2, and 56/162 (34.6%) in period 3, respectively. While no consistent tendency in the prevalence of burnout based on variables was observed throughout the periods, the prevalence of burnout tends to be higher in periods 1 and 3 in those who engaged in COVID-19 patient care in the last 2 weeks (50.0%, 30.8%, 43.1% in period 1, 2, and 3, respectively). Given the prolonged pandemic causing stigmatization and hatred against HCWs leading to increased prevalence of burnout, high-level interventions and supports are warranted

    Assessment of Melanoma-Initiating Cell Markers and Conventional Parameters in Sentinel Lymph Nodes of Malignant Melanoma

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    Sentinel lymph node (SLN) biopsies have widely been used for the detection of occult LN metastasis of malignant melanoma (MM). In addition to conventional biomarkers, we assessed the diagnostic and prognostic significance of melanoma-initiating cell (MIC) markers in SLNs of MM. We examined the expressions of gp100, MART-1 and tyrosinase mRNA for routine diagnosis and those of ABCB5, CD133, nestin, KDM5B, NGFR and RANK mRNA as MIC markers. The presence of micrometastasis was confirmed immunohistochemically using antibodies to S-100, HMB-45, MART-1, and tyrosinase. Discordance between immunohistochemical and molecular data was observed in 14 of 70 (20.0%) patients, among whom five (7.1%) were positive for only molecular markers;two of these five patients tested positive for micrometastasis by repeated immunohistochemical stainings. The quantitative expression levels of gp100, MART-1, and tyrosinase mRNA were significantly higher in the metastatic LNs;the cut-off values remain to be elucidated. ABCB5 mRNA expression was detected more frequently in the metastatic SLNs (p<0.05) and in the group of patients with recurrence. To make a definite diagnosis of metastasis, we still need a combination of immunohistochemical and molecular probes. ABCB5 might be a suitable molecular marker for the detection of melanoma-initiating cells in SLNs

    Sustainability and Fairness Simulations Based on Decision-Making Model of Utility Function and Norm Function

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    We introduced a decision-making model based on value functions that included individualistic utility function and socio-constructivistic norm function and proposed a norm-fostering process that recursively updates norm function through mutual recognition between the self and others. As an example, we looked at the resource-sharing problem typical of economic activities and assumed the distribution of individual actions to define the (1) norm function fostered through mutual comparison of value/action ratio based on the equity theory (progressive tax-like), (2) norm function proportional to resource utilization (proportional tax-like) and (3) fixed norm function independent of resource utilization (fixed tax-like). By carrying out numerical simulation, we showed that the progressive tax-like norm function (i) does not increase disparity for the distribution of the actions, unlike the other norm functions, and (ii) has high resource productivity and low Gini coefficient. Therefore the progressive tax-like norm function has the highest sustainability and fairness

    Emerging Evidence of Translational Control by AU-Rich Element-Binding Proteins

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    RNA-binding proteins (RBPs) are key regulators of posttranscriptional gene expression and control many important biological processes including cell proliferation, development, and differentiation. RBPs bind specific motifs in their target mRNAs and regulate mRNA fate at many steps. The AU-rich element (ARE) is one of the major cis-regulatory elements in the 3′ untranslated region (UTR) of labile mRNAs. Many of these encode factors requiring very tight regulation, such as inflammatory cytokines and growth factors. Disruption in the control of these factors’ expression can cause autoimmune diseases, developmental disorders, or cancers. Therefore, these mRNAs are strictly regulated by various RBPs, particularly ARE-binding proteins (ARE-BPs). To regulate mRNA metabolism, ARE-BPs bind target mRNAs and affect some factors on mRNAs directly, or recruit effectors, such as mRNA decay machinery and protein kinases to target mRNAs. Importantly, some ARE-BPs have stabilizing roles, whereas others are destabilizing, and ARE-BPs appear to compete with each other when binding to target mRNAs. The function of specific ARE-BPs is modulated by posttranslational modifications (PTMs) including methylation and phosphorylation, thereby providing a means for cellular signaling pathways to regulate stability of specific target mRNAs. In this review, we summarize recent studies which have revealed detailed molecular mechanisms of ARE-BP-mediated regulation of gene expression and also report on the importance of ARE-BP function in specific physiological contexts and how this relates to disease. We also propose an mRNP regulatory network based on competition between stabilizing ARE-BPs and destabilizing ARE-BPs
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