2,878 research outputs found

    Cytotoxic and Anti-HIV Phenanthroindolizidine Alkaloids from Cryptocarya chinensis

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    Bioassay-guided fractionation of the cytotoxic ethanol extract of Cryptocarya chinensis has led to the isolation of 11 compounds, including two phenanthroindolizidine alkaloids [(−)-antofine (1) and dehydroantofine (2)], five pavine alkaloids (3–7), and four proaporphine alkaloids (8–11). The structures of the isolated compounds were determined by means of NMR spectroscopic methods, and supported by HRMS and optical rotation data. Compounds 1 and 2 showed cytotoxic activity against four cancer cell lines, L1210, P388, A549, and HCT-8, with 1 being the most potent against A549 and HCT-8 with EC50 values of 0.002 and 0.001 μg/mL, respectively. In addition, 2 is first reported to exhibit significant anti-HIV activity

    Cardiac Glycosides from Antiaris toxicaria with Potent Cardiotonic Activity

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    An ethanolic extract of Antiaris toxicaria trunk bark showed potent in vitro cardiotonic effect on isolated guinea pig atria. Bioassay-guided fractionation of the extract led to identification of 9 new cardiac glycosides (1–9, named antiarosides A-I), antiarotoxinin A (10), and 18 known compounds. Their structures were established using MS and NMR spectroscopic studies, including homonuclear and heteronuclear correlation experiments. The ability of these cardiotonic compounds to produce positive inotropic action and their safety indexes were examined in comparison with those of ouabain, a classical inhibitor of Na+/K+-ATPase. Malayoside (23) was nearly equipotent and had a similar safety index to ouabain in guinea pig atria. However, the maximal positive inotropic effect and safety index of 23 in papillary muscle were better than those of ouabain. An electrophysiological recording showed that 23 inhibited sodium pump current in a concentration-dependent manner

    Measuring Technical Efficiency and Returns to Scale in Taiwan’s Baking Industry―A Case Study of the 85 °C Company

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    [[abstract]]Under an intense internationally competitive business environment, it is important to understand the production efficiency of the baking industry, where efficient management is becoming increasingly important to ensure the sustainable development of the company. Thus, this study uses data envelopment analysis (DEA) to appraise the performance of a well-known baking company (85 °C) and uses input and output constructs to measure its technical efficiency and scale efficiency scores to understand the major reasons for efficiency losses from 2011 to 2016. The empirical results indicate that low technical efficiency is the major reason for lower pure technical efficiency, since the scale efficiency is higher than pure technical efficiency. This means 85 °C is still improving overall operating efficiency and space efficiency. Moreover, the results also show that the III-generation operations style is more technically efficient and pure-technically efficient compared to those of I-generation and II-generation. Furthermore, the company’s financial performance is dependent upon the producer’s ability to stay on the production frontier due to the result of a positive relationship between return on assets (ROA) and technical efficiency. Last but not least, this study shows that 85 °C can gain higher performance and efficiency by enhancing technical efficiency and reinforcing strategic alignments with business goals.[[notice]]補正完

    Growth of the [110] oriented TiO2 nanorods on ITO substrates by sputtering technique for dye-sensitized solar cells

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    TiO2 films have been deposited on ITO substrates by dc reactive magnetron sputtering technique. It has been found that the sputtering pressure is a very important parameter for the structure of the deposited TiO2 films. When the pressure is lower than 1 Pa, the deposited has a dense structure and shows a preferred orientation along the [101] direction. However, the nanorod structure has been obtained as the sputtering pressure is higher than 1 Pa. These nanorods structure TiO2 film shows a preferred orientation along the [110] direction. The x-ray diffraction and the Raman scattering measurements show both the dense and the nanostructure TiO2 films have only an anatase phase, no other phase has been obtained. The results of the SEM show that these TiO2 nanorods are perpendicular to the ITO substrate. The TEM measurement shows that the nanorods have a very rough surface. The dye-sensitized solar cells (DSSCs) have been assembled using these TiO2 nanorod films prepared at different sputtering pressures as photoelectrode. And the effect of the sputtering pressure on the properties of the photoelectric conversion of the DSSCs has been studied.This work is supported by the project PEst-OE/FIS/UI0068/2014-CEFITEC
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