109 research outputs found

    Local Buckling of Concrete Filled Rectangular Steel Tube with Longitudinal Stiffener under Axial Compression

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    Width-thickness ratio was an important parameter for designing Concrete Filled Rectangular Steel Tube (CFRST). Welding longitudinal stiffener on the internal wall of steel pipe could delay the local buckling, which increased the limit of width-thickness ratio. If there was not enough stiffener and its sectional dimension was too small, the local buckling of steel pipe would occur, inducing its bearing capacity seriously. If the stiffener sectional dimension was too large, concrete filled in steel tube would be broken up, which reduces its bearing capacity. To solve that problem, this paper studied local buckling of CFRST with longitudinal stiffener under axial compression and design of longitudinal stiffener. It established buckling analysis model, simplified local buckling analysis as calculating buckling load of thin plate clamped on loading side and unloading side under axial force. It deduced buckling load and buckling coefficient based on the principle of energy. The results showed that buckling mode depended on stiffening rigidity. Therefore, it put forward minimum stiffening rigidity ratio that controlled the stiffener design. This paper also came up with a formula to calculate minimum stiffening rigidity ratio. It provided guidance on designing number, sectional dimension and material performance

    Searching for Variable Stars in the Open Cluster NGC 2355 and Its Surrounding Region

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    We have investigated the variable stars in the field surrounding NGC 2355 based on the time-series photometric observation data. More than 3000 CCD frames were obtained in the V band spread over 13 nights with the Nanshan One-meter Wide-field Telescope. We have detected 88 variable stars, containing 72 new variable stars and 16 known variable stars. By analyzing these light curves, we classified the variable stars as follows: 26 eclipsing binaries, 52 pulsating stars, 4 rotating variables, and 6 unclear type variable stars for which their periods are much longer than the time baseline chosen. Employing Gaia DR2 parallax, kinematics, and photometry, the cluster membership of these variable stars were also analyzed for NGC 2355. In addition to the 11 variable members reported by Cantat-Gaudin et al. (2018), we identify 4 more variable member candidates located at the outer region of NGC 2355 and showed homogeneity in space positions and kinematic properties with the cluster members. The main physical parameters of NGC 2355 estimated from the two-color and color-magnitude diagrams are log(age/yr) = 8.9, E(B - V) = 0.24 mag, and [Fe/H] = - 0.07 dex.Comment: 15 pages, 11 figures. 6 tables,Accepted for publication in A

    Unipolar resistive switching of ZnO-single-wire memristors

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    Regulatory Effect of High-Protein Diet on Circadian Rhythm of Lipid Metabolism in Obese Mice

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    This study aimed to investigate the regulatory effect of high-protein diet on circadian rhythm disturbances of lipid metabolism in obese mice induced by high-fat diet. Totally 120 specific pathogen-free (SPF)-grade C57BL/6J mice were randomly divided into normal, high-fat and high-fat/high-protein groups. The metabolic status of mice was monitored at the 4th and 12th week of intervention, and mice were sacrificed at 2, 8, 14, and 20 o’clock after completion of feeding. Lipid levels in blood and liver, the expression of genes related to fat anabolism and catabolism and the expression of circadian rhythm-related genes were measured, and circadian rhythm changes were analyzed. The results showed that high-fat feeding caused an increase in body mass and obesity index and a decrease in voluntary activity and caloric expenditure during the active period. The changes were accompanied by dyslipidemia and an abnormal increase in liver lipid levels, manifested by continuous gene expression of acetyl-CoA carboxylase and fatty acid synthetase, key enzymes involved in fat anabolism in liver, at high levels during the active and resting periods, a slow increase in the gene expression of sensitive lipase and acetyl-CoA oxidase, key enzymes involved in fat catabolism in liver, and changes in the diurnal variation pattern. Compared with high-fat intervention, high-protein intervention significantly increased the amount of voluntary activity and energy expenditure during the active period, restored the expression rhythm of fat synthase that was higher during the active period and lower during the rest period, and resulted in high-level expression of ACOX, a key enzyme gene involved in fat catabolism, after ingestion, showing obvious circadian rhythms. Further analysis showed that the improvement effects of high-protein intervention on circadian rhythm disorders of lipid metabolism caused by high-fat diet were closely related to the regulation of the expression of two clock genes in liver, circadian locomotor output cycle kaput (CLOCK) and brain and muscle-Arnt-like protein 1 (BMAL1). In conclusion, high-protein diets can alleviate biological clock disorders in liver induced by high-fat diets and ameliorate hepatic lipid metabolism disorders in mice by stabilizing circadian rhythms

    Allele-specific induction of IL-1beta expression by C/EBPbeta and PU.1 contributes to increased tuberculosis susceptibility

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    Mycobacterium tuberculosis infection is associated with a spectrum of clinical outcomes, from long-term latent infection to different manifestations of progressive disease. Pro-inflammatory pathways, such as those controlled by IL-1beta, have the contrasting potential both to prevent disease by restricting bacterial replication, and to promote disease by inflicting tissue damage. Thus, the ultimate contribution of individual inflammatory pathways to the outcome of M. tuberculosis infection remains ambiguous. In this study, we identified a naturally-occurring polymorphism in the human IL1B promoter region, which alters the association of the C/EBPbeta and PU.1 transcription factors and controls Mtb-induced IL-1beta production. The high-IL-1beta expressing genotype was associated with the development of active tuberculosis, the severity of pulmonary disease and poor treatment outcome in TB patients. Higher IL-1beta expression did not suppress the activity of IFN-gamma-producing T cells, but instead correlated with neutrophil accumulation in the lung. These observations support a specific role for IL-1beta and granulocytic inflammation as a driver of TB disease progression in humans, and suggest novel strategies for the prevention and treatment of tuberculosis

    An Open Invitation to Join the International Brugada Electrocardiographic Indices Registry

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    Background: The Brugada Electrocardiographic Indices Registry is a comprehensive data registry composed of patients with Brugada patterns on the electrocardiogram (ECG). The aim is to test the hypotheses that (i) ECG indices combining both depolarization and repolarization abnormalities can better predict spontaneous ventricular arrhythmias than existing ECG markers in Brugada syndrome and (ii) that serial ECG measurements will provide additional information for risk stratification, especially in asymptomatic patients. Methods: Patients with both Brugada pattern ECGs and Brugada syndrome are eligible for inclusion in this registry. Baseline characteristics and ECG variables reflecting depolarization and repolarization will be determined. The primary outcome is spontaneous ventricular tachycardia/ventricular fibrillation or sudden cardiac death. Secondary outcomes are inducible ventricular tachycardia/ventricular fibrillation and syncope. Results: As of November 15, 2019, 39 investigators from 32 cities in 18 countries had joined this registry. As of December 15, 2019, 1383 cases had been enrolled. Conclusions: The Brugada Electrocardiographic Indices Registry will evaluate the disease life course, risk factors, and prognosis in a large series of Brugada patients. It will therefore provide insights for improving risk stratification
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