7,763 research outputs found

    Relationship Between the Kinetic Power and Bolometric Luminosity of Jets: limitation from black hole X-ray binaries, active galactic nuclei, and gamma-ray bursts

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    The correlation between the kinetic power PjetP_{\rm jet} and intrinsic bolometric luminosity LjetL_{\rm jet} of jets may reveal the underlying jet physics in various black hole systems. Based on the recent work by Nemmen et al. (2012), we re-investigate this correlation with additional sources of black-hole X-ray binaries (BXBs) in hard/quiescent states and low-luminosity active galactic nuclei (LLAGNs). The new sample includes 29 sets of data from 7 BXBs and 20 LLAGNs, with PjetP_{\rm jet} and LjetL_{\rm jet} being derived from spectral modeling of the quasi-simultaneous multi-band spectra under the accretion-jet scenario. Compared to previous works, the range of luminosity is now enlarged to more than 2020 decades, i.e. from 1031erg/s10^{31}{\rm erg/s} to 1052erg/s10^{52}{\rm erg/s}, which allows for better constraining of the correlation. One notable result is that the jets in BXBs and LLAGNs almost follow the same PjetLjetP_{\rm jet} - L_{\rm jet} correlation that was obtained from blazars and gamma-ray bursts (GRBs). The slope indices we derived are 1.03±0.011.03\pm0.01 for the whole sample, 0.85±0.060.85\pm0.06 for BXB subsample, 0.71±0.110.71\pm0.11 for LLAGN subsample, and 1.01±0.051.01\pm0.05 for the LLAGN-blazar subsample, respectively. The correlation index around unit implies the independence of jet efficiency on the luminosity or kinetic power. Our results may further support the hypothesis that similar physical processes exist in the jets of various black hole systems.Comment: 5 pages, 3 figures, to appear in ApJL, updated versio

    NEUROPILIN IN THE VASCULAR SYSTEM: MECHANISTIC BASIS OF ANGIOGENESIS

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    The vascular system is critical for maintaining homeostasis in all vertebrates. Structural studies of Neuropilin (Nrp), an essential angiogenic receptor, have defined its role in regulating angiogenesis, the formation of new vessels from the existing vasculature. Utilizing biochemical and biophysical tools we describe the ability of Nrp to function as a co-receptor for the VEGFR receptor tyrosine kinase. Two families of Nrp-1 ligands, Vascular Endothelial Growth Factor A (VEGF-A) and Semaphorin3F (Sema3F), physically compete for binding to the Nrp-1 b1 domain, and have opposite roles. VEGF-A is a potent pro-angiogenic cytokine while Sema3F is an angiogenesis inhibitor. Using coupled structural and functional studies, we have discovered the basis for potent competitive binding of Sema3F to Nrp1 requires engagement of two distinct binding sites. These data provide a basis for understanding the rational design of novel high affinity Nrp-1 inhibitor

    Glycosylated Collagen Interaction with Cells Through DDRs and Integrin

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    https://openworks.mdanderson.org/sumexp22/1009/thumbnail.jp

    Mechanism of Selective VEGF-A Binding by Neuropilin-1 Reveals a Basis for Specific Ligand Inhibition

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    Neuropilin (Nrp) receptors function as essential cell surface receptors for the Vascular Endothelial Growth Factor (VEGF) family of proangiogenic cytokines and the semaphorin 3 (Sema3) family of axon guidance molecules. There are two Nrp homologues, Nrp1 and Nrp2, which bind to both overlapping and distinct members of the VEGF and Sema3 family of molecules. Nrp1 specifically binds the VEGF-A164/5 isoform, which is essential for developmental angiogenesis. We demonstrate that VEGF-A specific binding is governed by Nrp1 residues in the b1 coagulation factor domain surrounding the invariant Nrp C-terminal arginine binding pocket. Further, we show that Sema3F does not display the Nrp-specific binding to the b1 domain seen with VEGF-A. Engineered soluble Nrp receptor fragments that selectively sequester ligands from the active signaling complex are an attractive modality for selectively blocking the angiogenic and chemorepulsive functions of Nrp ligands. Utilizing the information on Nrp ligand binding specificity, we demonstrate Nrp constructs that specifically sequester Sema3 in the presence of VEGF-A. This establishes that unique mechanisms are used by Nrp receptors to mediate specific ligand binding and that these differences can be exploited to engineer soluble Nrp receptors with specificity for Sema3

    Plasma Concentrations of Trace Elements Selenium and Cobalt During and After Coronary Artery Bypass Grafting Surgery

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    Trace elements selenium (Se) and cobalt (Co) are essential in the human body, and a correlation between Se and cardiac surgery has been suggested. We investigated the plasma concentrations of Se and Co during and after coronary artery bypass grafting (CABG) surgery under cardiopulmonary bypass (CPB). From December 2019 to January 2020, preoperative plasma samples from isolated first-time CABG patients (n=20; 10 males, 10 females) were prospectively collected post-anesthesia and before CPB (T1), 45 min after CPB started (T2), 90 min after CPB started (T3), and postoperative days 1 (T4), and day 4 (T5). The plasma concentrations of Se and Co were measured. The Se concentration was significantly decreased at T2 (105.24±4.08 vs. 68.56±2.42 μg/L, p<0.001) and T3 (105.24±4.08 vs. 80.41±3.40 μg/L, p<0.001). The Co concentration was significantly decreased at T4 (0.35±0.19 vs. 0.26±0.13 μg/L, p<0.01) and T5 (0.35±0.19 vs. 0.23±0.11 μg/L, p<0.001). Five patients developed atrial fibrillation (AF); there was no other operative mortality or major morbidity. This is the first report of alterations of plasma Se and Co concentrations during and after CABG surgery. Our results may indicate that Se supplementation before or during CABG and Co supplementation after CABG may become necessary for patients undergoing CABG

    Guanxintai Exerts Protective Effects on Ischemic Cardiomyocytes by Mitigating Oxidative Stress

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    Oxidative stress participates in numerous myocardial pathophysiological processes and is considered a therapeutic target for myocardial ischemia and heart failure. Guanxintai (GXT), a traditional Chinese medicine, is commonly used to treat cardiovascular disease on account of its numerous beneficial physiological activities, such as dilating coronary arteries, inhibiting platelet aggregation, and reducing the serum lipid content. However, the antioxidative properties of GXT and potential underlying mechanisms remain to be established. In the present study, we investigated the protective effects of GXT on ischemic cardiomyocytes and the associated antioxidative mechanisms, both in vivo and in vitro. Notably, GXT treatment reduced the degree of cardiomyocyte injury, myocardial apoptosis, and fibrosis and partially improved cardiac function after myocardial infarction. Furthermore, GXT suppressed the level of ROS as well as expression of NADPH oxidase (NOX) and phospho-p38 mitogen-activated protein kinase (MAPK) proteins. Our results collectively suggest that the protective effects of GXT on ischemic cardiomyocytes are exerted through its antioxidative activity of NOX inhibition

    catena-Poly[zinc(II)-bis­[μ2-3-(3-pyrid­yl)­benzoato]-κ2 O:N;κ2 N:O]

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    In the title compound, [Zn(C12H8NO2)2]n, the Zn2+ cation is coordinated by a pair of carboxyl­ate O atoms as well as two pyridyl N atoms to afford a distorted tetra­hedral environment. Adjacent Zn2+ cations, with a separation of 8.807 (2) Å, are linked by two 3-(3-pyrid­yl)benzoate ligand bridges, generating an infinite ribbon extending parallel to [001]

    RELATIONSHIP BETWEEN THE KINETIC POWER AND BOLOMETRIC LUMINOSITY OF JETS: LIMITATION FROM BLACK HOLE X-RAY BINARIES, ACTIVE GALACTIC NUCLEI, AND GAMMA-RAY BURSTS

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    Natural Science Foundation of China [11333004, 11203057, 11133005, 11233006, 11103059, 11103061, 11121062]; CAS/SAFEA International Partnership Program for Creative Research Teams; Natural Science Foundation of Fujian Province [2011J01023]The correlation between the kinetic power P-jet and intrinsic bolometric luminosity L-jet of jets may reveal the underlying jet physics in various black hole systems. Based on the recent work by Nemmen et al., we re-investigate this correlation with additional sources of black hole X-ray binaries (BXBs) in hard/quiescent states and low-luminosity active galactic nuclei (LLAGNs). The new sample includes 29 sets of data from 7 BXBs and 20 LLAGNs, with P-jet and L-jet being derived from spectral modeling of the quasi-simultaneous multi-band spectra under the accretion jet scenario. Compared to previous works, the range of luminosity is now enlarged to more than 20 decades, i.e., from similar to 10(31) erg s(-1) to similar to 10(52) erg s(-1), which allows for better constraining of the correlation. One notable result is that the jets in BXBs and LLAGNs almost follow the same P-jet-L-jet correlation that was obtained from blazars and gamma-ray bursts. The slope indices we derived are 1.03+/-0.01 for the whole sample, 0.85+/-0.06 for the BXB subsample, 0.71+/-0.11 for the LLAGN subsample, and 1.01+/-0.05 for the LLAGN-blazar subsample, respectively. The correlation index around unit implies the independence of jet efficiency on the luminosity or kinetic power. Our results may further support the hypothesis that similar physical processes exist in the jets of various black hole systems

    Predictive and prognostic value of aurora kinase A combined with tumor-infiltrating lymphocytes in medullary thyroid carcinoma

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    BackgroundAurora kinase A (AURKA) and tumor-infiltrating lymphocytes (TILs) are both known to play an essential role in tumorigenesis. However, the expression and prognostic value of the AURKA and TILs in medullary thyroid carcinoma (MTC) have not yet been investigated.Patients and methodsSurgical specimens and clinical data of 137 patients diagnosed with MTC were collected. AURKA expression and TILs infiltration were quantified by immunohistochemistry and hematoxylin-eosin staining. Subsequently, the prognostic value of AURKA expression and TIL infiltration in MTC was evaluated.ResultsAURKA was highly expressed in patients with multifocal tumor, cervical lymph node metastasis, and an advanced TNM stage, indicating a high probability of recurrence. AURKA further exhibited a positive correlation with TILs (R = 0.44, P &lt; 0.001). High expression of AURKA combined with a low numbers of TILs (AURKAhigh/TILslow) was identified as an independent prognostic factor for biochemical recurrence (odds ratio: 4.57, 95% confidence interval: 1.54–14.66, P &lt; 0.01) and recurrence-free survival (hazard ratio: 3.64, 95% confidence interval: 1.52–8.71, P &lt; 0.001). The combination of AURKA and TILs apparently improves the prognostic value for biochemical recurrence (area under the curve: 0.751) and structural recurrence (area under the curve: 0.836) of MTC. Notably, AURKAhigh/TILslow demonstrated a high value for prediction of distant or unresectable locoregional recurrence, with an overall accuracy of 86.9%.ConclusionAURKAhigh is associated with the MTC malignancy. The combination of AURKAhigh/TILslow was identified as novel independent prognostic marker in MTC, predicting incurable disease recurrence with high accuracy
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