879 research outputs found

    An update of the catalog of radial velocity standard stars from the APOGEE DR17

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    We present an updated catalog of 46,753 radial velocity (RV) standard stars selected from the APOGEE DR17. These stars cover the Northern and Southern Hemispheres almost evenly, with 62% being red giants and 38% being main-sequence stars. These RV standard stars are stable on a baseline longer than 200 days (54% longer than one year and 10% longer than five years) with a median stability better than 215 m s1^{-1}. The average observation number of those stars are 5 and each observation is required to have spectral-to-noise-ratio (SNR) greater than 50 and RV measurement error smaller than 500 m s1^{-1}. Based on the new APOGEE RV standard star catalog, we have checked the RV zero points (RVZPs) for current large-scale stellar spectroscopic surveys including RAVE, LAMOST, GALAH and Gaia. By carefully analysis, we estimate their mean RVZP to be +0.149+0.149 km s1^{-1}, +4.574+4.574 km s1^{-1} (for LRS), 0.031-0.031 km s1^{-1} and +0.014+0.014 km s1^{-1}, respectively, for the four surveys. In the RAVE, LAMOST (for MRS), GALAH and Gaia surveys, RVZP exhibits systematic trend with stellar parameters (mainly [Fe/H], TeffT_{\rm{eff}}, log gg, GBPGRPG_{\rm{BP}}-G_{\rm{RP}} and GRVSG_{\rm{RVS}}). The corrections of those small but clear RVZPs are of vital importances for these massive spectroscopic surveys in various studies that require extremely high radial velocity accuracies.Comment: 10 pages, 7 figures, 2 tables, accepted by RAA; full table can be accessed from https://nadc.china-vo.org/res/r101244

    Logarithmical Regularity Criteria of the Three-Dimensional Micropolar Fluid Equations in terms of the Pressure

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    This paper is devoted to the regularity criterion of the three-dimensional micropolar fluid equations. Some new regularity criteria in terms of the partial derivative of the pressure in the Lebesgue spaces and the Besov spaces are obtained which improve the previous results on the micropolar fluid equations

    (Pro)renin receptor-mediated myocardial injury, apoptosis, and inflammatory response in rats with diabetic cardiomyopathy

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    Excessive activation of the renin-angiotensin system (RAS) in diabetic cardiomyopathy (DCM) provokes a series of structural and functional abnormalities, and causes ventricular remodeling and heart failure in diabetes. (Pro)renin receptor (PRR) is a component of the RAS and has been reported to be up-regulated in some cardiovascular diseases. Furthermore, PRR blockade in some cardiovascular diseases, such as myocardial infarction and hypertension, has been demonstrated to reverse their pathogenesis. However, there have been few studies about the function of PRR in the pathogenesis of DCM. In this study, we hypothesized that PRR is involved in the pathogenesis of DCM and mediates myocardial injury in DCM. To explore the role of PRR in DCM, we evaluated the effects of PRR overexpression and knockdown on the DCM phenotype in vivo and in vitro. The results show that PRR overexpression exacerbates myocardial injury and the inflammatory response in rats with DCM. Conversely, PRR knockdown alleviates myocardial fibrosis, apoptosis, and the inflammatory response, reversing the cardiac dysfunction in rats with DCM. In cell experiments, PRR overexpression also up-regulated the protein expression of collagen I and fibronectin, aggravated the inflammatory response, and increased the production of reactive oxygen species (ROS), while PRR knockdown had the opposite effect. Thus, PRR mediates myocardial injury, apoptosis, and the inflammatory response, likely through a PRR/extracellular signal-regulated kinase/ROS pathway

    A broad-spectrum substrate for the human UDP-glucuronosyltransferases and its use for investigating glucuronidation inhibitors

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    Strong inhibition of the human UDP-glucuronosyltransferase enzymes (UGTs) may lead to undesirable effects, including hyperbilirubinaemia and drugiherb-drug interactions. Currently, there is no good way to examine the inhibitory effects and specificities of compounds toward all the important human UGTs, side-by-side and under identical conditions. Herein, we report a new, broad-spectrum substrate for human UGTs and its uses in screening and characterizing of UGT inhibitors. Following screening a variety of phenolic compound(s), we have found that methylophiopogonanone A (MOA) can be readily O-glucuronidated by all tested human UGTs, including the typical N-glucuronidating enzymes UGT1A4 and UGT2B10. MOA-O-glucuronidation yielded a single mono-O-glucuronide that was biosynthesized and purified for structural characterization and for constructing an LC-UV based MOA-O-glucuronidation activity assay, which was then used for investigating MOA-O-glucuronidation kinetics in recombinant human UGTs. The derived K-m values were crucial for selecting the most suitable assay conditions for assessing inhibitory potentials and specificity of test compound(s). Furthermore, the inhibitory effects and specificities of four known UGT inhibitors were reinvestigated by using MOA as the substrate for all tested UGTs. Collectively, MOA is a broad-spectrum substrate for the human UGTs, which offers a new and practical tool for assessing inhibitory effects and specificities of UGT inhibitors. (C) 2021 Elsevier B.V. All rights reserved.Peer reviewe

    N-(2-Chloro­benzo­yl)-N′-(3-pyrid­yl)thio­urea

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    In the mol­ecule of the title compound, C13H10ClN3OS, the dihedral angles between the plane through the thio­urea group and the pyridine and benzene rings are 53.08 (3) and 87.12 (3)°, respectively. The mol­ecules are linked by inter­molecular N—H⋯N hydrogen-bonding inter­actions to form a supra­molecular chain structure along the a axis. An intra­mol­ecular N—H⋯O hydrogen bond is also present
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