Samarium(II) Diiodide Induced Polarity Inversion of π-Allyl Palladium Complexes: The Formation of Allylic Selenides

As a versatile one-electron transfer reducing and coupling agent, samarium diiodide has been extensively used in organic synthesis in last decade. It has been reported that electrophilic p-allyl palladium complexes could undergo polarity inversion to nucleophilic species with the aid of SmI2, and could trap some electrophiles1. It is well known that allylic selenides are rather important intermediates in organic synthesis. They have been recognized as useful synthons of allylic anion stabi…     

Comparative analysis of the main bioactive components of Xin‐Sheng‐Hua granule and its single herbs by ultrahigh performance liquid chromatography with tandem mass spectrometry

Xin‐Sheng‐Hua granule, a representative formula for postpartum hemorrhage, has been used clinically to treat postpartum diseases. Its main bioactive components comprise aromatic acids, phthalides, alkaloids, flavonoids, and gingerols among others. To investigate the changes in main bioactive constituents in its seven single herbs before and after compatibility, a rapid, simple, and sensitive method was developed for comparative analysis of 27 main bioactive components by using ultrahigh‐performance liquid chromatography with triple quadrupole electrospray tandem mass spectrometry for the first time. The sufficient separation of 27 target constituents was achieved on a Thermo Scientific Hypersil GOLD column (100 mm × 3 mm, 1.9 μm) within 20 min under the optimized chromatographic conditions. Compared with the theoretical content, the observed content of each analyte showed remarkable differences in Xin‐Sheng‐Hua granule except thymine, p‐coumaric acid, senkyunolide I, senkyunolide H, and ligustilide; the total contents of 27 components increased significantly, and the content variation degrees for the different components were gingerols > flavonoids > aromatic acids > alkaloids > phthalides. The results could provide a good reference for the quality control of Xin‐Sheng‐Hua granule and might be helpful to interpret the drug interactions based on variation of bioactive components in formulae.     

Extraction and identification of steroidal saponins from Polygonatum cyrtonema Hua using natural deep eutectic solvent-synergistic quartz sand-assisted extraction method

In this study, quartz sand with particularly sharp nanoscale edges acted like a nanoscale knife physically cut cells of Polygonatum cyrtonema Hua into nanosized particles and was synergized with natural deep eutectic solvent to extract steroidal saponins of Polygonatum cyrtonema Hua. The natural deep eutectic solvent (choline chloride-lactic acid)-synergistic quartz sand-assisted extraction was optimized using response surface methodology. The steroidal saponins purified with AB-8 macroporous resin were identified using ultra-high-performance liquid chromatography-triple time of flight mass spectrometry. The results showed that the experimental total saponins content value (36.97 ± 0.12 mg dioscin equivalent/g dry weight) at optimal extraction conditions with a temperature of 68°C, a rotational speed of 20 400 rpm, shear time of 4.3 min, the liquid-solid ratio of 38 ml/g, was close to the maximum possible theoretical value (36.64 mg dioscin equivalent/g dry weight). A total of 20 steroidal saponins were identified, among which the content of (25R)-Kingianoside E was the highest (102.66 ± 3.47 mg/g). Furthermore, a new steroid saponin (3β,25S)-26-(β-D-glucopyranosyloxy)-22-hydroxyfurost-5-en-3-yl 4-O-β-D-glucopyranosyl-β-D-galactopyranoside+Glc was found for the first time. These results revealed that natural deep eutectic solvent-synergistic quartz sand-assisted extraction was an efficient and green method to extract a variety of steroidal saponins.     

华蘅芳数在幂和问题中的新应用

自然效的幂和问题具有悠久的历史,亦不乏现代的兴趣.一般学者不了解清代数学家华蘅芳的成果.本文改进了华氏数的定义;针对该问题建立了新的取盒-放球模型,给出幂和的组合解释;应用华氏数获得了简捷的幂和公式.文末介绍了华氏数的历史来源.     

New alkylamides from pericarps of Zanthoxylum bungeanum

Two new unsaturated alkylamides(2E,7E,9E)-N-(2-hydroxy-2-methylpropyl)-6,11-dioxo-2,7,9-dodecatrienamide(1) and (2E,6E,8E)-N-(2-hydroxy-2-methylpropyl)-10-oxo-2,6,8-decatrienamide(2) together with six known compounds(3-8) have been isolated from the pericarps of Zanthoxylum bungeanum.Their structures were elucidated on the basis of extensive spectroscopic analysis,including MS,IR,1D and 2D NMR experiments.     

追忆我的大学老师华罗庚先生

华罗庚先生离开我们已经25年了.作为他的一个老学生,对60多年前他所给予的种种指导和启发,我仍记忆犹新.谨以此文追忆华罗庚先生在大学任教期间的部分轶闻趣事,以勾勒其非凡的人生阅历、展现其特有的学术风范、彰显其崇高的个人品质.     

华罗庚域研究的综述

华罗庚域的创建,统一了多复变中的对称典型域和蛋型域的研究,给多复变函数论提供了一个新的研究领域．对华罗庚域的研究,至今已经取得了一系列重要成果．本文简单介绍了华罗庚域创建的历史并着重介绍了华罗庚域上的Bergman核函数和Einstein-Khler度量的显表达式的计算,以及4个经典度量(Bergman度量,Carathéodory度量,Einstein-Kahler度量, Kobayashi度量)之间的等价关系,包括这些度量与Kobayashi度量的比较定理,阐述了Bergman度量等价于Einstein-Khler度量的这一丘成桐猜想在华罗庚域的特例Cartan-Hartogs域上也成立．着重指出了获得这些结果的新的思想和方法并提出了一些尚未解决的问题,以期更多的学者对华罗庚域感到兴趣并进行更深入的研究．     

Lu Qi-Keng conjectue and Hua domain

The first part of this paper discusses the motivation for the Lu Qi-Keng conjecture and the results about the presence or the absence of zeroes of the Bergman kernel function of a bounded domain in C~n.Its second part summarizes the main results on the Hua domains,such as the explicit Bergman kernel function,the comparison theorem for the invariant metrics,the explicit complete Einstein-K(?)hler metrics,the equivalence between the Einstein-K(?)hler metric and the Bergman metric,etc.     

The Einstein-Kähler metric on Hua construction of the first type

Let HC_I be the Hua construction of the first type. We describe the Einstein-Kähler metric for HC_I. We reduce the Monge-Ampè re equation for the metric to an ordinary differential equation in the auxiliary function\(X\left( {z,w,\zeta } \right)\) This differential equation can be solved to give an implicit function in\(X\left( {z,w,\zeta } \right)\). For some cases, we obtained the solution of the differential equation and the explicit forms of the complete Einstein-Kähler metrics on HC_I which are the non-homogeneous domains.     

再论筹方法中活动延续时间的统计学性质

In this paper attempts are made at answering the problems on the statistical properties of activity flow time in PERT raised by the late famous mathematician Hua Loo-keng.