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991.
A sensitive and accurate LC–MS/MS method was established for quantifying salvianolic acid B (Sal B), rosmarinic acid (Ros A) and Danshensu (DA) in rat plasma. Salvia miltiorrhiza polyphenolic acid (SMPA), active water‐soluble ingredients isolated and purified from Salvia miltiorrhiza Bge included Sal B, Ros A and DA. The pharmacokinetic analysis of Sal B, Ros A and DA after pulmonary administration of SMPA solution to rat was performed by LC–MS/MS. Results from the pharmacokinetic studies showed that the peak concentration of DA was 21.85 ± 6.43 and 65.39 ± 3.83 ng/mL after pulmonary and intravenous administration, respectively. DA was not detected at 2 h after administration. The absolute bioavailabilities of Sal B and Ros A were respectively 50.37 ± 27.04 and 89.63 ± 12.16% after pulmonary administration of 10 mg/kg SMPA solution in rats. The absolute bioavailability of Sal B increased at least 10‐fold after pulmonary administration, compared with oral administration. It was concluded that the newly established LC–MS/MS method was suitable for describing the pharmacokinetic characteristics of Sal B, Ros A and DA in rat after pulmonary administration of SMPA solution. The data from this study will provide a preclinical insight into the feasibility of pulmonary administration of SMPA.  相似文献   
992.
993.
994.
离散元方法广泛应用于海冰,特别是碎冰区的动力过程及其对海洋结构作用过程的数值模拟。为构造碎冰区中的冰块几何特性,基于二维Voronoi图方法对计算域进行随机切割以生成碎冰区中冰块的几何形态,并采用球体单元对每个碎冰块单元进行填充,从而确定碎冰区的初始分布场。在采用Voronoi图进行碎冰区构造时,可对冰块尺寸、几何形态和密集度等海冰参数进行设定。为确定冰块的不同几何规则度,综合采用排斥法和扰动法以定量地控制碎冰块几何形态从完全随机分布到规则分布的连续变换。为分析不同几何规则度下碎冰块的几何特性概率分布规律,对计算域内冰块的面积和边数等参数进行统计分析,从而可更合理地参数化控制初始冰场中碎冰块的几何特性。在此基础上,本文基于粘接-破碎的球体离散元方法对不同冰况下锥体结构的冰荷载进行了数值计算,讨论分析了碎冰区的海冰密集度、冰块面积和几何规则度对冰载荷的影响。  相似文献   
995.
996.
n-Propylamine and n-butylamine showed an inhibitory effect on cellulase A and cellulase B, while ethanediamine displayed a positive effect on both of these cellulases. Relative filter paper activity and relative CMCase activity of cellulase A and cellulase B measured at 50 °C were increased by 16.0 and 25.2 %, and 18.9 and 13.9 %, respectively, by the appearance of ethanediamine at a certain concentration. Also the addition of ethanediamine maintained the thermal stability of cellulase A and B at 65 °C to some extent and showed a stronger stabilizing effect on cellulase A than cellulase B. Third, the addition of ethanediamine within a certain concentration range enhanced the bio-polishing effect of cotton fabric enzymatic treatment at 50 °C to some extent, obtaining a close bio-polishing effect of cotton fabrics treated at 50 °C; the addition of ethanediamine saved some of the dose of cellulase A and B. Last but not least, the appearance of ethanediamine broadened the operating temperature of cellulase A to 65 °C, and it had a less positive effect on cellulase B at 65 °C.  相似文献   
997.
A synthesis has been developed for 2,3,7,8,12,13-hexakis[2-(2-methoxyethoxy)ethoxy]-tricycloquinazoline (TCQ6EO2M) in which the ethylenoxy side chains are introduced before elaboration of the heterocylic core. This discogen gives a hexagonal columnar phase (Colh) between 77 and 233°C. n-Doping using potassium metal is facilitated firstly by the electron poor/π-deficient nature of the core and secondly by the polyethylenoxy side chains which complex the potassium K+ counter-ions. The conductivity of the Colh phase of TCQ6EO2M doped with 10 mol % potassium (σ = 1.1 x 10-3 S m-1) is substantially higher than that previously reported for 2,3,7,8,12,13-hexa(hexylthio)tricycloquinazoline doped with 6 mol % potassium (σ = 2.9 x 10-5 S m-1). Photoconductivity studies of TCQ6EO2M using a time of flight sample configuration show transient photocurrents for both holes and electrons. From these an upper limit on the mobility for the electrons is estimated as ~10-4 cm2 V-1 s-1 at 150°C which is of the same magnitude as that for hole mobilities in other columnar discotic liquid crystals.  相似文献   
998.
999.
Abstract

A simple, inexpensive, and efficient one-pot synthesis of 2-arylthiazoline derivatives under solvent-free conditions using a catalytic amount of 1-butyl-3-methylimidazolium tribromide with excellent product yields is reported. This methodology provides easy, quantitative access to various 2-arylthiazoline derivatives, using environmentally benign 1-butyl-3-methylimidazolium tribromide as a catalyst.  相似文献   
1000.
Surface cracks could improve the optical and photoelectronic properties of crystalline materials as they increase specific surface area, but the controlled self-assembly of fullerene (C60) molecules into micro-/nanostructures with surface cracks is still challenging. Herein, we report the morphology engineering of novel C60 microstructures bearing surface cracks for the first time, selecting phenetole and propan-1-ol (NPA) as good and poor solvents, respectively. Our systematic investigations reveal that phenetole molecules initially participate in the formation of the ends of the C60 microstructures, and then NPA molecules are involved in the gradual growth of the sidewalls of the microstructures. Therefore, the surface cracks of C60 microstructures can be finely regulated by adjusting the addition of NPA and the crystallization time. Interestingly, the cracked C60 microstructures show superior photoluminescence properties relative to the smooth microstructures due to the increased specific surface area. In addition, C60 microstructures with wide cracks show preferential recognition of silica particles over C60 particles owing to electrostatic interactions between the negatively charged C60 microstructures and the positively charged silica microparticles. These C60 crystals with surface cracks have potential applications from optoelectronics to biology.  相似文献   
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