681 research outputs found

    Summary of a Topical Forum FAQ Based on the Chinese Composition Structure

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    An automatic multiple-document summarization system for producing frequently asked questions (FAQ) of a topical forum can save forum Webmasters a great deal of time in theory. This work will address summary composition issue of a previous work by proposing a structured presentation based on a four-part pattern of traditional Chinese articles. The result of the experiment shows that the enhanced system with both domain-terminology corpus methods produced a significantly better summary presentation than the original system. Recall rate and precision rate performance indices and user evaluations are also presented and discussed to show their practical implications

    Bilinear effect in complex systems

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    The distribution of the lifetime of Chinese dynasties (as well as that of the British Isles and Japan) in a linear Zipf plot is found to consist of two straight lines intersecting at a transition point. This two-section piecewise-linear distribution is different from the power law or the stretched exponent distribution, and is called the Bilinear Effect for short. With assumptions mimicking the organization of ancient Chinese regimes, a 3-layer network model is constructed. Numerical results of this model show the bilinear effect, providing a plausible explanation of the historical data. Bilinear effect in two other social systems is presented, indicating that such a piecewise-linear effect is widespread in social systems.Comment: 5 pages, 5 figure

    IsaB Inhibits Autophagic Flux to Promote Host Transmission of Methicillin-Resistant Staphylococcus aureus.

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    Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major nosocomial pathogen that is widespread in both health-care facilities and in the community at large, as a result of direct host-to-host transmission. Several virulence factors are associated with pathogen transmission to naive hosts. Immunodominant surface antigen B (IsaB) is a virulence factor that helps Staphylococcus aureus to evade the host defense system. However, the mechanism of IsaB on host transmissibility remains unclear. We found that IsaB expression was elevated in transmissible MRSA. Wild-type isaB strains inhibited autophagic flux to promote bacterial survival and elicit inflammation in THP-1 cells and mouse skin. MRSA isolates with increased IsaB expression showed decreased autophagic flux, and the MRSA isolate with the lowest IsaB expression showed increased autophagic flux. In addition, recombinant IsaB rescued the virulence of the isaB deletion strain and increased the group A streptococcus (GAS) virulence in vivo. Together, these results reveal that IsaB diminishes autophagic flux, thereby allowing MRSA to evade host degradation. These findings suggest that IsaB is a suitable target for preventing or treating MRSA infection

    Vertically-aligned graphene nanowalls grown via plasma-enhanced chemical vapor deposition as a binder-free cathode in Li-O_2 batteries

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    In the present report, vertically-aligned graphene nanowalls are grown on Ni foam (VA-G/NF) using plasma-enhanced chemical vapor deposition method at room temperature. Optimization of the growth conditions provides graphene sheets with controlled defect sites. The unique architecture of the vertically-aligned graphene sheets allows sufficient space for the ionic movement within the sheets and hence enhancing the catalytic activity. Further modification with ruthenium nanoparticles (Ru NPs) drop-casted on VA-G/NF improves the charge overpotential for lithium–oxygen (Li–O_2) battery cycles. Such reduction we believe is due to the easier passage of ions between the perpendicularly standing graphene sheets thereby providing ionic channels

    Vertically-aligned graphene nanowalls grown via plasma-enhanced chemical vapor deposition as a binder-free cathode in Li-O_2 batteries

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    In the present report, vertically-aligned graphene nanowalls are grown on Ni foam (VA-G/NF) using plasma-enhanced chemical vapor deposition method at room temperature. Optimization of the growth conditions provides graphene sheets with controlled defect sites. The unique architecture of the vertically-aligned graphene sheets allows sufficient space for the ionic movement within the sheets and hence enhancing the catalytic activity. Further modification with ruthenium nanoparticles (Ru NPs) drop-casted on VA-G/NF improves the charge overpotential for lithium–oxygen (Li–O_2) battery cycles. Such reduction we believe is due to the easier passage of ions between the perpendicularly standing graphene sheets thereby providing ionic channels

    Identification of overexpressed cytokines as serum biomarkers of hepatitis C virus-induced liver fibrosis using bead-based flexible multiple analyte profiling

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    Hepatic inflammation is the stimulator to activate hepatic stellate cells (HSCs) and triggers fibrogenesis. Cytokines are produced during liver inflammation and maybe considered as liver fibrosis biomarker. The aim of this study was to investigate whether cytokines can be used as reliable biomarkers of liver fibrosis using flexible multi-analyte profiling (xMAP). A total of 61 chronic hepatitis C patients with different severity of liver fibrosis were enrolled. Liver biopsy was used as standard to assess the severity of fibrosis according to METAVIR classification. Afterward, 15 samples from healthy controls were analyzed and totally 50 cytokines were screened using flexible multi-analyte profiling to discover differential biomarkers. Finally, levels of protein expressions of individual stages of liver fibrosis were measured. In histological examination, the necroinflammatory score (histology activity index, HAI) was increased from F1 to F4 stage in hepatitis C virus (HCV) infected patients, indicating that inflammation was accompanied with the progression of liver fibrosis. Using flexible multi-analyte profiling, four serum cytokines, including IFN-α2 (p=0.023), GRO-α (p=0.013), SCF (p=0.047) and SDF-1α p=0.024), were identified under antibody specific recognition and elevated with HAI score. This study reveals the relationship between cytokines and liver fibrosis, and demonstrated that IFN-α2, GRO-α, SCF and SDF-1 α may be used as biomarkers to predict liver fibrosis. The overexpressed cytokines may play a role in the progression of liver fibrosis and deserves further investigation.Keywords: Cytokine, flexible multi-analyte profiling, hepatitis C virus, liver fibrosisAfrican Journal of Biotechnology Vol. 11(29), pp. 7535-7541, 29 April, 201

    Pressure-Controlled Chemical Vapor Deposition of Graphene as Catalyst for Solar Hydrogen Evolution Reaction

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    In the present report, graphene-based catalysts on silicon substrate have been examined as the photocathode for solar hydrogen evolution reaction (HER). Mono-layered graphene has been synthesized through low-pressure chemical vapor deposition (LPCVD), whereas multi-layered graphene has been synthesized by atmospheric pressure chemical vapor deposition (APCVD). Copper foil is used as the substrate. The graphene layer on Cu foil subsequently transferred on to silicon photoabsorber using poly(methyl-2-methylpropenoate) (PMMA). At the initial linear sweep voltammetry (LSV) scan, LPCVD-synthesized graphene-Si (LPCVD-Si) electrode showed an onset potential of −0.65 V and photocurrent of −4.31 mA cm^(−2) (at −0.385 V). On the contrary, the onset potential and photocurrent of APCVD-prepared graphene-Si (APCVD-Si) photocathode are −0.36 V and −28.28 mA cm^(−2) (at −0.385 V), respectively. After the 130th LSV scan, the onset potential and photocurrent of LPCVD-Si improved to −0.39 V and −13.28 mA cm^(−2) (at −0.385 V), respectively. In addition, the onset potential and photocurrent of APCVD-Si photocathode at the LSV 130th scan are enhanced to −0.36 V and −28.28 mA cm^(−2) (at −0.385 V), respectively. The graphene sample grown via LPCVD-Si show stable performance whereas, the graphene obtained via APCVD-Si have higher photocurrent poor stability

    Costunolide causes mitotic arrest and enhances radiosensitivity in human hepatocellular carcinoma cells

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    <p>Abstract</p> <p>Purpose</p> <p>This work aimed to investigate the effect of costunolide, a sesquiterpene lactone isolated from <it>Michelia compressa</it>, on cell cycle distribution and radiosensitivity of human hepatocellular carcinoma (HCC) cells.</p> <p>Methods</p> <p>The assessment used in this study included: cell viability assay, cell cycle analysis by DNA histogram, expression of phosphorylated histone H3 (Ser 10) by flow cytometer, mitotic index by Liu's stain and morphological observation, mitotic spindle alignment by immunofluorescence of alpha-tubulin, expression of cell cycle-related proteins by Western blotting, and radiation survival by clonogenic assay.</p> <p>Results</p> <p>Our results show that costunolide reduced the viability of HA22T/VGH cells. It caused a rapid G2/M arrest at 4 hours shown by DNA histogram. The increase in phosphorylated histone H3 (Ser 10)-positive cells and mitotic index indicates costunolide-treated cells are arrested at mitosis, not G2, phase. Immunofluorescence of alpha-tubulin for spindle formation further demonstrated these cells are halted at metaphase. Costunolide up-regulated the expression of phosphorylated Chk2 (Thr 68), phosphorylated Cdc25c (Ser 216), phosphorylated Cdk1 (Tyr 15) and cyclin B1 in HA22T/VGH cells. At optimal condition causing mitotic arrest, costunolide sensitized HA22T/VGH HCC cells to ionizing radiation with sensitizer enhancement ratio up to 1.9.</p> <p>Conclusions</p> <p>Costunolide could reduce the viability and arrest cell cycling at mitosis in hepatoma cells. Logical exploration of this mitosis-arresting activity for cancer therapeutics shows costunolide enhanced the killing effect of radiotherapy against human HCC cells.</p
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