1,378 research outputs found
A Model for Type-IIP Supernovae with Medium Recombination Approximation
In this paper, we propose a new light-curve model for Type-IIP supernovae
(SNe IIP) with an approximation of medium recombination. Recombination of
hydrogen that takes place in the envelope is believed highly affect the light
curves of SNe IIP. The propagation of the recombination wave through the
expanding envelope is crucial to determine the temperature and the bolometric
luminosity. Several approximations were made in previous works to determine the
recombination front, which plays a role as the pseudo-photosphere. With the
Eddington boundary condition, we let the actual photosphere be the boundary to
determine the time evolution of temperature profile of the envelope and
calculate the bolometric luminosity. A new approximation on the speed of
recombination wave is introduced to get a closer result to the real situation.
We abandon the non-self-consistent approximations made in former works and
solve the initial hump problem in the previous attempt for the slow
recombination approximation. The produced light curves show the necessity of
this approximation and fit the observation well.Comment: 14 pages, 10 figures, 5 tables. Submitted to ApJ, welcome for
comments
Two-Temperature GRMHD Simulations of Black Hole Accretion Flows with Multiple Magnetic Loops
We have performed a series of two-dimensional two-temperature general
relativistic magnetohydrodynamic simulations of magnetized accretion flows
initiated from tori with different sizes and poloidal magnetic loop polarities.
In these two temperature simulations, we trace the process of heating electrons
through turbulence and reconnection, most of the time these electrons are
trapped in plasmoids. We found that the accretion process strongly depends on
the size of the magnetic loops. The accretion flows never reach the
magnetically arrested (MAD) regime in small loop cases. Interaction between
magnetic field with different polarities dissipates and decreases the
efficiency of magneto-rotational instability. The dependency on the wavelength
of the loops places a lower limit on the loop size. In the large loop cases,
after reaching a quasi-steady phase, a transition from Standard And Normal
Evolution (SANE) flow to MAD flow is observed. The transition of the accretion
state and the transition time depends on the initial loop wavelength. The
formation of plasmoids strongly depends on the size of the magnetic loops. The
frequent magnetic reconnection between the magnetic loops is responsible for
the formation of most of the plasmoids. For some plasmoids, Kelvin-Helmholtz
and tearing instabilities are coexisting, showing another channel of plasmoid
formation. The simulations present that electrons in the plasmoids are
well-heated up by turbulent and magnetic reconnection. Different properties of
plasmoid formation in different magnetic field configurations provide new
insights for the understanding of flaring activity and electron thermodynamics
in Sgr A*.Comment: 18 pages, 25 figures, accepted for publication in MNRA
Clinical effects of sirolimus treatment in patients with increased serum creatinine levels after renal transplant
Purpose: To observe the clinical effects of sirolimus (SRL) immunosuppressive therapy in patients with progressively increasing levels of serum creatinine (Scr) after renal transplant.Methods: In total, 180 patients whose Scr levels had been rising after renal transplant were given an oral calcineurin inhibitor (CNI): either cyclosporine A (CsA) or tacrolimus (FK506). All patients were treated at People’s Hospital of Zhengzhou, China, between January 2011 and December 2013, and were given SRL-based conversion treatment. Scr level and glomerular filtration rate (GFR) were observed before and 1, 3, and 6 months after treatment initiation. In addition, liver function, blood glucose, blood lipid levels, rejection reaction incidence, and mortality were recorded to evaluate the effects of SRL.Results: Scr levels were 116.60 ± 30.60 μmol/L and 119.00 ± 24.60 μmol/L, and GFR was 70.00 ± 19.70 mL/min and 75.90 ± 15.60 mL/min, at 3 and 6 months after treatment, respectively. The 3- and 6- month Scr and GFR values were statistically different (p < 0.05) compared to pre-treatment levels (Scr: 144.10 ± 61.70 μmol/L vs and GFR: 59.10 ± 16.20 mL/min. Acute rejection (AR) occurred in 20 patients (13.30 %) within 6 months of treatment initiation, but rejection was reversed with conventional methylprednisolone therapy. Twenty-one patients (11.70 %) developed lung infections, but all were cured. There were no significant differences in liver function before and after treatment.Conclusion: SRL-based immunosuppressive therapy is effective in treating patients with increased Scr levels after renal transplant.Keywords: Renal transplant, Serum creatinine, Calcineurin inhibitors, Sirolimus, Acute rejection, Glomerular filtration rat
{μ-trans-N,N′-Bis[(diphenylphosphanyl)methyl]benzene-1,4-diamine-κ2 P:P′}bis{(acetonitrile-κN)[dipyrido[3,2-a:2′,3′-c]phenazine-κ2 N 4,N 5]copper(I)} bis(tetrafluoridoborate)
In the centrosymmetric dinuclear title compound, [Cu2(C2H3N)2(C18H10N4)2(C32H30N2P2)](BF4)2, the CuI centre is coordinated by two N atoms from a dipyridophenazine ligand, one P atom from an N,N′-bis[(diphenylphosphanyl)methyl]benzene-1,4-diamine (bpbda) ligand, and one N atom from an acetonitrile molecule in a distorted tetrahedral geometry. The bpbda ligand, lying on an inversion center, bridges two CuI centres into a Z-shaped complex. Intramolecular π–π interactions between the dipyridophenazine ligand and the benzene ring of the bpbda ligand are observed [centroid–centroid distance = 3.459 (3) Å]. The crystal structure also involves intermolecular π–π interactions between the dipyridophenazine ligands [centroid–centroid distance = 3.506 (3) Å], which lead to a one-dimensional supramolecular structure
catena-Poly[[dinitratocopper(II)]-μ-4,4′′-bis(1H-benzimidazol-1-yl)-1,1′:4′,1′′-terphenyl]
In the title one-dimensional coordination polymer, [Cu(NO3)2(C32H22N4)]n, the Cu2+ ion (site symmetry 2) is coordinated by two nitrate O atoms and two N atoms from two 4,4′-bis(benzoimidazol-1-yl)terphenyl (L) ligands in a distorted cis-CuN2O2 square-planar coordination geometry. An alternative description of the metal coordination geometry, if long Cu—O contacts to the bonded nitrate anions are considered, is an extremely distorted cis-CuN2O4 octahedron. The complete L ligand is generated by crystallographic twofold symmetry and connects the metal ions into infinite chains propagating in [10]. The dihedral angle between the benzimidazole ring system and the adjacent benzene (B) ring is 51.12 (11)° and the dihedral angle between the B ring and the central ring is 19.45 (13)°
Isochorismatase domain-containing protein 1 (ISOC1) participates in DNA damage repair and inflammation-related pathways to promote lung cancer development
Background: The advent of novel molecular targets has dramatically changed the treatment landscape of lung cancer in recent years. Isochorismatase domain-containing protein 1 (ISOC1) has been reported as a potential biomarker in gastrointestinal cancer, while its function in lung cancer has not been determined.Methods: The expression levels and prognostic significance of ISOC1 were assessed using bioinformatic analysis. Overexpression of ISOC1 and miR-4633, and knockdown of ISOC1 in non-small cell lung cancer (NSCLC) cell lines were generated by lentiviral infection with overexpressed or shRNA plasmids. CRISPR/Cas9 system was applied to knockout ISOC1 in A549 cells. The functions of ISOC1 and miR-4633 in lung cancer development were investigated using cell proliferation, migration, and invasion assays. Xenograft tumor growth assays in nude mice were further assessed the effect of ISOC1 in the tumorigenesis of NSCLC in vivo. Cell cycle distribution analysis was performed to uncover the underlying mechanism of ISOC1 and miR-4633 in promoting NSCLC cell proliferation. Co-immunoprecipitation combined with mass spectrometry and RNA sequencing were performed to uncover the potential mechanism of ISOC1 in lung cancer development.Results: Our results found that ISOC1 expression was upregulated in NSCLC tissues and that increased expression of ISOC1 was significantly associated with worse disease-free survival in NSCLC patients. Overexpression of ISOC1 could increase the proliferation, viability, migration, and invasion of NSCLC cells. Furthermore, miR-4633, located in the first intron of ISOC1, could also promote tumor cell progression and metastasis. Mice xenograft tumor assay showed that knockout of ISOC1 could significantly inhibit tumor growth in vivo. Besides, co-immunoprecipitation combined with mass spectrometry assay revealed that ISOC1 interacted with the proteins of DNA damage repair pathways and that upregulated ISOC1 expression could significantly increase the number of DNA damage lesions. RNA sequencing analysis showed that the downstream signaling pathways mediated by ISOC1 were mainly inflammation-related.Conclusions: We demonstrated that ISOC1 and its intronic miR-4633, both of them could promote NSCLC cell proliferation, migration, invasion, and cell cycle progression. ISOC1 participates in DNA damage repair and inflammation to promote lung cancer development
Seismic behavior of steel-reinforced high-strength concrete composite beams with bonded tendons
To study the seismic behavior of steel-reinforced high-strength concrete composite beams with bonded tendons (PSRHSCBs) under low cyclic loading, 13 PSRHSCBs were designed with the main parameters of the span-to-height ratio of beams (L/H), the cubic strength of concrete (fcu), the eccentricity of H-shaped steel (eH), the volume stirrup ratio (pv), the longitudinal reinforcement ratio (p), and the tension control stress of tendons(σcon). Using the simplified bilinear constitutive model of steel and the nonlinear constitutive model of high-strength concrete, and introducing plastic damage of concrete, fine finite element models were established with ABAQUS software. 11 similar test specimens were conducted by above modeling method, by comparing existing test curves and numerical simulation curves, both of them match well, which verified the validity of the modeling method. Subsequently, parameter analysis for 13 PSRHSCB specimens was performed, and the influence regularity of different parameters on the seismic behavior of this kind of composite beams was obtained. The results show that hysteretic curves of this kind of composite beams are full, and the failure mode is manifested as bending failure. The ultimate load, the energy dissipation capacity and the ductility coefficient of specimens can be improved significantly by increasing pv, on the contrary, the energy dissipation capacity and the ductility coefficient decrease gradually by increasing fcu. The stiffness degradation of specimens significantly slows down with the increasing of L/H and σcon, and the decreasing of eH. Finally, the trilinear skeleton curve model and the restoring force model are established by statistical regression, and the corresponding seismic design suggestions are given, and these can provide theoretical support for the seismic design of such composite beams in actual engineering
Identifying SYNE1 Ataxia With Novel Mutations in a Chinese Population
Objective: Variants in SYNE1 have been widely reported in ataxia patients in Europe, with highly variable clinical phenotype. Until now, no mutation of SYNE1 ataxia has been reported among the Chinese population. Our aim was to screen for SYNE1 ataxia patients in China and extend the clinicogenetic spectrum.Methods: Variants in SYNE1 were detected by high-throughput sequencing on a cohort of 126 unrelated index patients with unexplained autosomal recessive or sporadic ataxia. Pathogenicity assessments of SYNE1 variants were interpreted according to the ACMG guidelines. Potential pathogenic variants were confirmed by Sanger sequencing. Clinical assessments were conducted by two experienced neurologists.Results: Two Chinese families with variable ataxia syndrome were identified (accounting for 1.6%; 2/126), separately caused by the novel homozygous SYNE1 mutation (NM_033071.3: c.21568C>T, p.Arg7190Ter), and compound heterozygous SYNE1 mutation (NM_033071.3: c.18684G>A, p.Trp6228Ter; c.17944C>T, p.Arg5982Ter), characterized by motor neuron impairment, mental retardation and arthrogryposis.Conclusions:SYNE1 ataxia exists in the Chinese population, as a rare form of autosomal recessive ataxia, with a complex phenotype. Our findings expanded the ethnic, phenotypic and genetic diversity of SYNE1 ataxia
Recent updates in click and computational chemistry for drug discovery and development
Drug discovery is a costly and time-consuming process with a very high failure rate. Recently, click chemistry and computer-aided drug design (CADD) represent popular areas for new drug development. Herein, we summarized the recent updates in click and computational chemistry for drug discovery and development including clicking to effectively synthesize druggable candidates, synthesis and modification of natural products, targeted delivery systems, and computer-aided drug discovery for target identification, seeking out and optimizing lead compounds, ADMET prediction as well as compounds synthesis, hopefully, inspires new ideas for novel drug development in the future
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