389 research outputs found

    The complementary contribution of each order topology into the synchronization of multi-order networks

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    ACKNOWLEDGMENTS This work is supported by the National Natural Science Foundation of China (Grant No. 12072262).Peer reviewedPostprin

    Thermodynamic model of coherent island formation on vicinal substrate

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    A thermodynamic model has been proposed to address the formation of coherent island on the vicinal substrate. The morphological transition from square based island to elongated based one with various substrate misorientations is described. The initial stage of nucleation and growth process of islands in Stranski-Krastanow system is studied by taking into account the elastic deformations and the change of energy in the case of two-dimensional growth mode. The theoretical analysis shows the minimum nucleation barrier of island is on the decrease with increment of substrate misorientation, which means the nucleation of island on vicinal substrate is more favorable than that on flat substrate. By using the fitting data of experimental results done by Persichetti et al., [Phys. Rev. Lett. 104, 036104 (2010) and Phys. Rev. B 82, 121309(R) (2010)], we provide a meaningful explanation of the experimental observations

    Determination of tetramethylpyrazine in rat plasma by liquid chromatography/electrospray mass spectrometry

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    A sensitive and selective liquid chromatography/electrospray mass spectrometry (LC-ESIMS) method for determination of tetramethylpyrazine in rat plasma was developed. After addition of phenacetin as internal standard, protein precipitation by acetonitrile was used as sample preparation. Chromatographic separation was achieved on a Zorbax SB-C18 (2.1 mm×150 mm, 5 µm) column with (40:60, v/v) acetonitrile-water containing 0.1 % formic acid as mobile phase. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to quantify tetramethylpyrazine using target fragment ions m/z 136.9 for tetramethylpyrazine and m/z 179.8 for the IS. Calibration plots were linear over the range of 20-4000 ng/mL for tetramethylpyrazine in plasma. Lower limit of quantitation (LLOQ) for tetramethylpyrazine was 20 ng/mL. Mean recovery of tetramethylpyrazine from plasma was in the range 95.4-97.2 %. RSD of intra-day and inter-day precision were less than 9 %, respectively. This method is simple, sensitive and fast enough to be used in pharmacokinetic research for determination of tetramethylpyrazine in rat plasma.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Determination of tetramethylpyrazine in rat plasma by liquid chromatography/electrospray mass spectrometry

    Get PDF
    A sensitive and selective liquid chromatography/electrospray mass spectrometry (LC-ESIMS) method for determination of tetramethylpyrazine in rat plasma was developed. After addition of phenacetin as internal standard, protein precipitation by acetonitrile was used as sample preparation. Chromatographic separation was achieved on a Zorbax SB-C18 (2.1 mm×150 mm, 5 µm) column with (40:60, v/v) acetonitrile-water containing 0.1 % formic acid as mobile phase. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to quantify tetramethylpyrazine using target fragment ions m/z 136.9 for tetramethylpyrazine and m/z 179.8 for the IS. Calibration plots were linear over the range of 20-4000 ng/mL for tetramethylpyrazine in plasma. Lower limit of quantitation (LLOQ) for tetramethylpyrazine was 20 ng/mL. Mean recovery of tetramethylpyrazine from plasma was in the range 95.4-97.2 %. RSD of intra-day and inter-day precision were less than 9 %, respectively. This method is simple, sensitive and fast enough to be used in pharmacokinetic research for determination of tetramethylpyrazine in rat plasma.Colegio de Farmacéuticos de la Provincia de Buenos Aire
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