植物单宁的生物降解

植物单宁的生物降解对于拓展这类天然产物的应用领域，使其获得高附加值利用有重要的意义。本文较全面的综述了这一研究领域的发展现状和趋势，并根据笔者的研究体会，对技术方法和学术观点进行了一些规律性的总结和归纳。     

A retrospective reliability test for numeric data sets applied by example to atomic-mass values of some nuclides

 Under favorable conditions, a retrospective test for reliability of published sets of physical property data becomes possible. The test and the necessary conditions for its use are discussed. The test is applied, by example, to well-documented, periodically republished nuclidic (atomic) masses of nine low atomic number nuclides. An index of reliability is suggested and evaluated for the example. Revised: 27 November 1995     

Preparation and certification of new thorium isotopic reference materials

Preparation of two Isotopic Reference Materials of thorium has been performed, starting from highly enriched ²³²Th (99.99%) and ²³⁰Th (99.8%). After full characterization (chemical and isotopic) of these purified base materials the thorium nitrate was transformed to thorium dioxide. Accurately weighed amounts of the two isotopes in the dioxide form were subsequently dissolved in nitric acid and resulted in solutions with amount ratios n(²³⁰Th)/n(²³²Th) close to 10^–5 (IRMM-035) and 3 · 10^–6 (IRMM-036). These gravimetrically prepared ratios were finally verified by means of Thermal Ionization Mass Spectrometry (TIMS). The purpose of the Reference Materials is to calibrate thorium isotope amount ratio measurements. Received: 7 July 1997 / Revised: 1 December 1997 / Accepted: 7 December 1997     

On the Rainich geometrization of a vector meson field in the Kibble theory

The variables of a vector meson field are determined within the framework of the Kibble theory as the functions of the metric tensor, affine connection and their derivatives and a system of differential equations is found for the metric tensor and affine connection which is equivalent to the equations of motion of gravitational and vector meson fields.     

Two new sesquiterpene lactones from the fruits of Illicium jiadifengpi

Two new seco-prezizaane-type sesquiterpenes, 3,4-dehydroneomajucin (1) and 1,2,3,4-tetradehydroneomajucin (2), were isolated from the fruits of Illicium jiadifengpi. The structure of these compounds was determined using 1D and 2D NMR and ESI-MS. The isolates were evaluated for their anti-hepatitis B virus activities on the Hep G2.2.15 cell line. The inhibitory rates of compounds 1 and 2 on the HBeAg and HBsAg expression were 30.08 ± 3.09% and 11.43 ± 1.92% at a concentrations of 68.00 μM and 7.88 ± 1.21% and 16.96 ± 4.24% at a concentration of 68.50 μM, respectively.     

Identification and determination of the major constituents in Kai‐Xin‐San by UPLC‐Q/TOF MS and UFLC‐MS/MS method

In order to have overall chemical material information of Kai‐Xin‐San (KXS), the reliable ultra‐high‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometer (UHPLC–Q‐TOF‐MS) and ultra‐fast liquid chromatography mass spectrometer (UFLC‐MS/MS) methods were developed for the identification and determination of the major constituents in KXS. Moreover, the UHPLC–Q‐TOF‐MS method was also applied to screen for multiple absorbed components in rat plasma after oral administration of KXS. The UHPLC–Q‐TOF‐MS method was achieved on Agilent 6520 Q‐TOF mass and operated in the negative ion mode. Good separation was performed on a ZORBAX Eclipse Plus C18 column with a gradient elution at a flow rate of 0.2 ml/min. A total of 92 compounds in KXS were identified or tentatively characterized based on their exact molecular weights, fragmentation patterns, and literature data. A total of 26 compounds including 23 prototype components and three metabolites were identified in rat plasma after oral administration of KXS. Then, 16 major bioactive constituents were chosen as the benchmark substances to evaluate the quality of KXS. Their quantitative analyses were performed by a triple quadrupole tandem mass spectrometer (MS/MS) operating in multiple‐reaction monitoring mode(MRM). The analysis was completed with a gradient elution at a flow rate of 0.4 ml/min within 35 min. The simple and fast method was validated and showed good linearity, precision, and recovery. Furthermore, the method was successful applied for the determination of 16 compounds in KXS. All results would provide essential data for identification and quality control of active chemical constituents in KXS. Copyright © 2016 John Wiley & Sons, Ltd.     

HPLC analysis and pharmacokinetic study of quercitrin and isoquercitrin in rat plasma after administration of Hypericum japonicum thunb. extract

A simple HPLC method was developed for determination of quercitrin and isoquercitrin in rat plasma. Reversed-phase HPLC was employed for the quantitative analysis using kaempferol-3-O-beta-D-glucopyranoside-7-O-alpha-L-rhamnoside as an internal standard. Following extraction from the plasma samples with ethyl acetate-isopropanol (95:5, v/v), these two compounds were successfully separated on a Luna C(18) column (250 x 4.6 mm, 5 microm) with isocratic elution of acetonitrile-0.5% aqueous acetic acid (17:83, v/v) as the mobile phase. The flow-rate was set at 1 mL/min and the eluent was detected at 350 nm for both quercitrin and isoquercitrin. The method was linear over the studied ranges of 50-6000 and 50-5000 ng/mL for quercitrin and isoquercitrin, respectively. The intra- and inter-day precisions of the analysis were better than 13.1 and 13.2%, respectively. The lower limits of quantitation for quercitrin and isoquercitrin in plasma were both of 50 ng/mL. The mean extraction recoveries were 73 and 61% for quercitrin and isoquercitrin, respectively. The validated method was successfully applied to pharmacokinetic studies of the two analytes in rat plasma after the oral administration of Hypericum japonicum thunb. ethanol extract.