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991.
Development and validation of an LC/MS/MS method for simultaneous determination of shionone and epi‐friedelinol in rat plasma for pharmacokinetic study after oral administration of Aster tataricus extract
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De‐Feng Yin Kai Zhou Ji‐Tao Liu Li Hu Ying Liu Jun Deng Song‐Ping Wang Ying Xiong Wu Zhong 《Biomedical chromatography : BMC》2016,30(7):1112-1117
A rapid and sensitive liquid chromatography tandem mass spectrometry (LC/MS/MS) method was developed and validated using spinasterol as the internal standard (IS) for the simultaneous determination of shionone and epi‐friedelinol in rat plasma. Plasma samples were pretreated using liquid–liquid extraction with ethyl ether. Chromatographic separation was achieved on a C18 column (100 × 2.1 mm, 5 μm) with an isocratic elution consisting of acetonitrile–0.1% formic acid water (75:25, v/v) at a flow rate of 0.30 mL/min. Detection was performed under the selected reaction monitoring scan using an electrospray ionization in the positive ion mode. The mass transitions were as follows: m/z 427.4 → 95.1 for shionone, m/z 411.4 → 205.2 for epi‐friedelinol and m/z 395.3 → 105.2 for IS. All calibration curves exhibited good linearity (r > 0.995) over the concentration range for both components. The intra‐ and inter‐day precisions at three QC and lower limit of quantitation levels were both <10.21% in terms of relative standard deviation, and the accuracy ranged from ?7.13 to 8.02% in terms of relative error. The extraction recoveries of the compounds ranged from 82.07 to 89.81%. The developed method was successfully applied to the pharmacokinetic study of shionone and epi‐friedelinol after oral administration of Aster tataricus extract to rats. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
992.
In this paper, we prove some spectral properties of the drifted Laplacian of self-shrinkers properly immersed in gradient shrinking Ricci solitons. Then we use these results to prove some geometric properties of self-shrinkers. For example, we describe a collection of domains in the ambient space that cannot contain self-shrinkers. 相似文献
993.
994.
Musammir Khan Yakai Feng Dazhi Yang Wei Zhou Hong Tian Ying Han Li Zhang Wenjie Yuan Jin Zhang Jintang Guo Wencheng Zhang 《Journal of polymer science. Part A, Polymer chemistry》2013,51(15):3166-3176
The synthetic polycations are ideal candidates as antimicrobial agents, because they resemble natural antimicrobial peptides, but to render hemocompatibility to these materials is a great challenge. Herein, we used 2‐(tert‐butyl‐aminoethyl) methacrylate (TBAEMA), to synthesize its homopolymer and pegylated random and diblock copolymers with polyethyleneglycol methacrylate (PEGMA, Mn = 360 Da) by single‐electron transfer–living radical polymerization (SET‐LRP). In the second step, the secondary amino groups in the precursor polymers were quaternized with iodomethane and bromohexane, to obtain three series of quaternized polymers. The antimicrobial properties of these quaternized polymers were evaluated against Escherichia coli (E. coli), by studying the minimum inhibitory concentrations (MICs) which ranged between 32 and 200 mg L?1 and showed higher values for the quaternized random than the diblock copolymers. In addition to, we have also demonstrated the grafting of these polycations onto polycarbonate urethane film surfaces, which showed good killing efficacy against E. coli. Furthermore, the hemolysis of these materials was investigated against human red blood cells, which indicated that except the quaternized homopolymers that showed highest hemolysis, all other amphiphilic polycations exhibited very low hemolytic activity. Therefore, our designed materials with controlled structures and functionality, synthesized from cheaply available resources could serve as useful agents in the field of biomedicines and implantable materials. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3166–3176 相似文献
995.
996.
Phase separation dynamics of a poly(vinyl methyl ether)/polystyrene (PVME/PS) blend studied by ultrafast differential scanning calorimetry
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Shaochuan Luo Lai Wei Jing Jiang Ye Sha Gi Xue Xiaoliang Wang Dongshan Zhou 《Journal of Polymer Science.Polymer Physics》2017,55(18):1357-1364
In this work, ultrafast differential scanning calorimetry (UFDSC) is used to study the dynamics of phase separation. Taking poly(vinyl methyl ether)/polystyrene (PVME/PS) blend as the example, we firstly obtained the phase diagram that has lower critical solution temperature (LCST), together with the glass transition temperature (Tg) of the homogeneous blend with different composition. Then, the dynamics of the phase separation of the PVME/PS blend with a mass ratio of 7:3 was studied in the time range from milliseconds to hours, by the virtue of small time and spatial resolution that UFDSC offers. The time dependence of the glass transition temperature (Tg) of PVME‐rich phase, shows a distinct change when the annealing temperature (Ta) changes from below to above 385 K. This corresponds to the transition from the nucleation and growth (NG) mechanism to the spinodal decomposition (SD) mechanism, as was verified by morphological and rheometric investigations. For the SD mechanism, the temperature‐dependent composition evolution in PVME‐rich domain was found to follow the Williams–Landel–Ferry (WLF) laws. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1357–1364 相似文献
997.
998.
Rigui Zhou Huian Wang Qian Wu Yang Shi 《International Journal of Theoretical Physics》2012,51(3):705-723
Based on analysis on properties of quantum linear superposition, to overcome the complexity of existing quantum associative
memory which was proposed by Ventura, a new storage method for multiply patterns is proposed in this paper by constructing
the quantum array with the binary decision diagrams. Also, the adoption of the nonlinear search algorithm increases the pattern
recalling speed of this model which has multiply patterns to O( log22n -t ) = O( n - t )O( {\log_{2}}^{2^{n -t}} ) = O( n - t ) time complexity, where n is the number of quantum bit and t is the quantum information of the t quantum bit. Results of case analysis show that the associative neural network model proposed in this paper based on quantum
learning is much better and optimized than other researchers’ counterparts both in terms of avoiding the additional qubits
or extraordinary initial operators, storing pattern and improving the recalling speed. 相似文献
999.
Yuechun Shi Simin Li Yating Zhou Linlin Lu Lianyan Li Yijun Feng Xiangfei Chen 《Optics & Laser Technology》2012,44(8):2443-2448
A λ/4 phase-shifted distributed feedback (DFB) semiconductor laser with a preformed chirped grating used to compensate the spatial hole burning (SHB) induced index change is proposed and analyzed. It shows that compared with the three phase shifted DFB laser which is known for its good performance to eliminate SHB, the proposed SHB compensated laser has better single longitudinal mode property, narrower spectral linewidth and better dynamic characteristics. 相似文献
1000.