2,954 research outputs found

    Chemical Composition and Cytotoxic Activities of Petroleum Ether Fruit Extract of Fruits of Brucea javanica (Simarubaceae)

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    Purpose: To investigate the chemical composition and antitumor activity of the petroleum ether extract of the dried ripe fruits of Brucea javanica.Methods: The composition of petroleum ether extract was analyzed by gas chromatography/mass spectrometric (GC/MS) and their antitumor activities were determined by MTT assay.Results: GC/MS spectrometry results indicate that the petroleum ether extract was a mixture of esters, fatty acids, sterides, pregnanones, terpenes, alkaloids, alkenes, alcohols, ketones, aldehydes and other compounds. The results also revealed the significant antitumor activity of the extract with IC50 of 9.14, 12.45, 15.15, 16.13, 22.26, and 27.97 μg/mL against A549, CNE, MCF-7, NCI-H460, HepG2, and KB-3-1 cell lines, respectively.Conclusion: The study establishes the chemical composition and cytotoxic activity of the petroleum ether extract of the plant fruits. There is need for further investigations to isolate more potent compounds and structurally modify the known compounds to retain activity and lower toxicity and thus lead to the possible development of Brucea javanica oil.Keywords: Brucae javanica, Mass spectra, Cytotoxic activity, Anti-tumour

    Intensity Distribution Design for Laser-Induced Thermal Loading Based on Numerical Simulation

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    To accomplish laser-induced thermal loading simulation tests for pistons,the Gaussian beam was modulated into multi-circular beam with specific intensity distribution.A reverse method was proposed to design the intensity distribution for the laser-induced thermal loading based on finite element(FE) analysis.Firstly,the FE model is improved by alternating parameters of boundary conditions and thermal-physical properties of piston material in a reasonable range,therefore it can simulate the experimental resul..

    Analysis of genetic diversity and construction of core collection of local mulberry varieties from Shanxi Province based on ISSR marker

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    Genetic diversity of 73 local mulberry varieties from Shanxi Province were screened using ISSR markers, with l5 primers combinations selected for their reproducibility and polymorphism. 129 bands were amplified, of which 115 bands showed polymorphism and the ratio of polymorphism bands was 89.15%. Nei’s genetic similarity coefficients ranged from 0.5891 to 0.9457 with an average of 0.7674. The observed number of alleles of each loci, effective number of alleles of each loci, Nei’s gene diversity, Shannon’s information index were 1.8915, 1.4771, 0.2780 and 0.4197, respectively. Clustering results showed that the 73 varieties could be divided into three different groups and nine subgroups. By using stepwise clustering and random methods and the modified heuristic algorithm, 21 core collections were constructed and the ratio of core collection was 28.77%. The result of t-test to the parameters (the number effective of alleles, Nei's genetic diversity index and Shannon's information index) showed that there was not significant difference between the core collection and initial sample with the exception of the number of observed alleles, that is, the core collection could well represent the initial sample.Key words: Mulberry, germplasm resource, genetic diversity, ISSR, cluster analysis, core collection

    Flux pinning mechanisms in graphene-doped MGB2 superconductors

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    The effects of graphene doping on the superconducting properties of MgB2 were studied. We found that small addition of graphene significantly improves the superconducting properties of MgB2, with only a small reduction in Tc. Low resistivity, high critical fields and enhanced flux-flow activation energy were observed for the optimally doped bulk sample. The spatial fluctuation in the transition temperature (dTc pinning) is the flux pinning mechanism in graphene-doped MgB2. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

    Synthesis and application of environmental friendly waterborne polyurethane

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    2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    The impact of cardiovascular disease and chronic kidney disease on life expectancy and direct medical cost in a 10-year diabetes cohort study

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    Objective: The relative effects of various cardiovascular diseases (CVD) and varying severity of chronic kidney disease (CKD) on mortality risk, direct medical cost and life expectancy in patients with diabetes mellitus (DM) are unclear. The aim of this study was to evaluate these associations. / Research Design and Methods: This was a retrospective cohort study that included 208,792 adults with diabetes stratified into 12 disease status groups with varying combinations of heart disease, stroke, moderate CKD (eGFR:30-59ml/min/1.73m2) and severe CKD (eGFR: <30ml/min/1.73m2) in 2008-2010. The effect of risk mortality, annual direct medical costs and life expectancy were assessed using Cox regression, Gamma generalized linear with log link function, and flexible parametric survival models. / Results: Over a median follow-up of 8.5 years (1.6 million patient-years), 50,154 deaths were recorded. Mortality risks for patients with only a single condition among heart disease, stroke and moderate CKD were similar. The mortality risks were 1.75 times, 2.63 times and 3.58 times greater for patients with one, two and all three conditions (consisting of stroke, heart disease and moderate CKD), compared with patients without these diseases, suggesting an independent and individually additive effect for any combination. A similar trend was observed in annual public healthcare costs with 2.91, 3.90 and 3.88 fold increased costs for patients with one, two and three conditions, respectively. Increases in the number of conditions reduced life expectancy greatly, particularly in younger patients. Reduction in life expectancy for a 40-year-old with one, two and three conditions were 20, 25, 30 years for men and 25, 30, 35 years for women. A similar trend of greater magnitude was observed for severe CKD. / Conclusion: The effect of heart diseases, stroke, CKD and the combination of these conditions on all-cause mortality and direct medical costs are independent and cumulative. CKD, especially severe CKD, appears to have a particularly significant impact on life expectancy and direct medical costs in patients with diabetes. These finding supports the importance of preventing both CVD and CKD in patients with DM

    Meta-Regression on the Heterogenous Factors Contributing to the Prevalence of Mental Health Symptoms During the COVID-19 Crisis Among Healthcare Workers.

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    Objective: This paper used meta-regression to analyze the heterogenous factors contributing to the prevalence rate of mental health symptoms of the general and frontline healthcare workers (HCWs) in China under the COVID-19 crisis. Method: We systematically searched PubMed, Embase, Web of Science, and Medrxiv and pooled data using random-effects meta-analyses to estimate the prevalence rates, and ran meta-regression to tease out the key sources of the heterogeneity. Results: The meta-regression results uncovered several predictors of the heterogeneity in prevalence rates among published studies, including severity (e.g., above severe vs. above moderate, p < 0.01; above moderate vs. above mild, p < 0.01), type of mental symptoms (PTSD vs. anxiety, p = 0.04), population (frontline vs. general HCWs, p < 0.01), sampling location (Wuhan vs. Non-Wuhan, p = 0.04), and study quality (p = 0.04). Conclusion: The meta-regression findings provide evidence on the factors contributing to the prevalence rate of mental health symptoms of the general and frontline healthcare workers (HCWs) to guide future research and evidence-based medicine in several specific directions. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=220592, identifier: CRD42020220592

    Search for K_S K_L in psi'' decays

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    K_S K_L from psi'' decays is searched for using the psi'' data collected by BESII at BEPC, the upper limit of the branching fraction is determined to be B(psi''--> K_S K_L) < 2.1\times 10^{-4} at 90% C. L. The measurement is compared with the prediction of the S- and D-wave mixing model of the charmonia, based on the measurements of the branching fractions of J/psi-->K_S K_L and psi'-->K_S K_L.Comment: 5 pages, 1 figur

    Visualization of vortex motion in FeAs-based BaFe<inf>1.9</inf>Ni <inf>0.1</inf>As<inf>2</inf> single crystal by means of magneto-optical imaging

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    Superconductivity has been found in newly discovered iron-based compounds. This paper studies the motion of magnetic vortices in BaFe1.9Ni 0.1As2 single crystal by means of the magneto-optical imaging technique. A series of magneto-optical images reflecting magnetic flux distribution at the crystal surface were taken when the crystal was zero-field cooled to 10 K. The behavior of the vortices, including penetration into and expulsion from the single crystal with increasing and decreasing external fields, respectively, is discussed. The motion behavior is similar to that observed in high-Tc superconducting cuprates with strong vortex pinning; however, the flux-front is irregular due to randomly distributed defects in the crystal. © 2011 American Institute of Physics

    Study of psi(2S) decays to X J/psi

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    Using J/psi -> mu^+ mu^- decays from a sample of approximately 4 million psi(2S) events collected with the BESI detector, the branching fractions of psi(2S) -> eta J/psi, pi^0 pi^0 J/psi, and anything J/psi normalized to that of psi(2S) -> pi^+ pi^- J/psi are measured. The results are B(psi(2S) -> eta J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 0.098 \pm 0.005 \pm 0.010, B(psi(2S) -> pi^0 pi^0 J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 0.570 \pm 0.009 \pm 0.026, and B(psi(2S) -> anything J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 1.867 \pm 0.026 \pm 0.055.Comment: 13 pages, 8 figure
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