Hatted 1T/2H-Phase MoS2 on Ni3S2 Nanorods for Efficient Overall Water Splitting in Alkaline Media

A new hatted 1T/2H-phase MoS₂ on Ni₃S₂ nanorods, as a bifunctional electrocatalyst for overall water splitting in alkaline media, is prepared through a simple one-pot hydrothermal synthesis. The hat-rod structure is composed mainly of Ni₃S₂, with 1T/2H-MoS₂ adhered to the top of the growth. Aqueous ammonia plays an important role in forming the 1T-phase MoS₂ by twisting the 2H-phase transition and expanding the interlayer spacing through the intercalation of NH₃/NH₄⁺. Owing to the special “hat-like” structure, the electrons conduct easily from Ni foam along Ni₃S₂ to MoS₂, and the catalyst particles maintain sufficient contact with the electrolyte, with gaseous molecules produced by water splitting easily removed from the surface of the catalyst. Thus, the electrocatalytic performance is enhanced, with an overpotential of 73 mV, a Tafel slope of 79 mV dec⁻¹, and excellent stability, and the OER demonstrates an overpotential of 190 mV and Tafel slope of 166 mV dec⁻¹.     

Ultra‐high‐performance liquid chromatography with tandem mass spectrometry method for determination of four compounds in rat plasma after oral administration of Xanthii fructus and stir‐fried Xanthii fructus extracts

Xanthii fructus (XF), the fruit of Xanthium sibiricum Patr., is a traditional Chinese materia medica commonly used to treat allergic rhinitis and other rhinitis diseases. To uncover the mechanism of the stir‐frying process and its effect on the pharmacokinetic behavior of active compounds in model rats, four active compounds—chlorogenic acid, 4‐caffeoylquinic acid, 1,5‐O‐dicaffeoylquinic acid and apigenin—were selected based on previous spectrum‐effect experiments. High performance liquid chromatography tandem triple quadrupole mass spectrometry (UPLC–QqQ–MS) technology, an accurate and feasible method, was applied to measure the concentration of these four compounds in rat plasma. This validated method can accurately measure the concentration of each compound at each sampling point of rat plasma. This validated method shows good linearity, extraction recoveries, matrix effects, intra‐ and inter‐day precision and stabilities. Compared with the XF group, the maximum plasma concentration (C_max) value of 1,5‐O‐dicaffeoylquinic acid decreased remarkably (p < 0.05) after oral administration of stir‐fried Xanthii fructus (SXF) extract, while the other compounds showed no significant difference. The mean residence time value of chlorogenic acid (p < 0.05) and 1,5‐O‐dicaffeoylquinic acid (p<0.01) after oral administration of SXF extraction demonstrated significant differences compared with the XF group, while the other two compounds showed no statistical difference, indicating that the stir‐frying process prolonged the effect time and delayed the removal time of chlorogenic acid and 1,5‐O‐dicaffeoylquinic acid. The values of the area under the plasma concentration–time curve from zero to the last quantifiable time‐point, the area under the plasma concentration–time curve from zero to infinity, the time to maximum concentration and the elimination half‐life of four compounds in the SXF group showed no statistically significant difference from the XF group. From this data, we speculated that the stir‐frying process can not only keep the absorption of 4‐caffeoylquinic acid and apigenin, but also increase the effect time of chlorogenic acid and 1,5‐O‐dicaffeoylquinic acid, which could be the mechanism underlying the stir‐frying process enhancing the effects of XF.     

POLYMERIZATION OF 1-OCTENE AND DETERMINATION OF MARKHOUWINK CONSTANTS OF POLY(1-OCTENE)

The polymerization of 1-octene initiated by methylalumoxane(MAO)-activated Ni(Ⅱ)-based-α-diimine complexes[(2,6-i-Pr)_2C_6H_3-DAB(An)]NiBr_2 was investigated.Using this catalyst,poly(1-octene)s with molecular weight between 100×10~3 and 400×10~3 and polydispersity(M_w/M_n) between 1.3 and 1.5 were synthesized successfully by varying reaction time at room temperature.The poly(1-octene)s were amorphous polymers and could be well soluble in tetrahydrofuran(THF).After fractional precipitation,poly(1-octene)s...     

中药炮制过程化学机理研究

中药炮制是中国的一项传统制药技术,也是中药区别于天然药物的显著特点。中药材经过加工炮制以后发生了复杂的化学变化,随着这些化学变化而改变的物质基础是中药炮制前后性味、功能改变的重要原因。阐明中药炮制过程中发生的这些化学变化是中药炮制机理研究的主要内容。近年来,国内外很多研究机构对中药炮制过程的化学机理进行了深入研究,初步阐明了多味中药炮制过程中发生的化学反应及化学成分变化,主要的化学反应包括水解反应、氧化反应、置换反应、异构化反应和分解反应等。本文对近年来中药炮制过程中化学反应机理领域取得的研究成果进行了综述,并对中药炮制过程化学机理研究的方向及前景进行了探讨。     

A new cytotoxic cardenolide from the latex of Antiaris toxicaria

A new cardenolide,toxicarioside E(1),was isolated from the latex ofAntiaris toxicaria(Pers.) Lesch(Moraceae).Its structure was elucidated on the basis of spectral data and chemical evidence.Compound 1 showed significant cytotoxicity against K562 and SGC-7901 cell lines in vitro by MTT method with the IC_(50) value of 0.026 and 0.027μg/mL,respectively.     

碳纳米管负载/促进的Mo-Co加氢脱硫催化剂

 以多壁碳纳米管(CNT)为载体制备了负载型Mo-Co/CNT,并将其用于噻吩HDS反应. 结果表明,在n(C4H4S)/n(H2)= 2.3/97.7, GHSV=2200 ml/(g·h),p=0.1 MPa和T=623 K的条件下,在7.2%(Mo-Co)/CNT催化剂上,噻吩HDS的比反应速率可达到0.64·10-3s-1,分别是9.7%(Mo-Co)/γ-Al2O3和16.9%(Mo-Co)/AC催化剂上的1.68和2.28倍. 对比研究结果表明,用CNT代替γ-Al2O3或AC并不引起催化剂上噻吩HDS反应的表观活化能发生明显变化. 与Mo-Co/γ-Al2O3或Mo-Co/AC催化剂相比,一方面,Mo-Co/CNT催化剂更易在较低温度下还原活化,并导致工作态催化剂表层活性Mo物种(Mo4+)在总Mo量中所占比例明显提高; 另一方面,Mo-Co/CNT催化剂对H2具有更强的吸附和活化能力. 这两个因素对提高催化剂活性都有重要贡献.     

关于几个能量公式的适用范围

利用能量公式中交换积分项符号的正负，给出产生交换作用的电子间的自旋特征。据此判断出几个能量公式的适用范围     

Simultaneous quantitative analyses of five constituents in crude and salt-processed Cuscutae Semen using a validated high-performance thin-layer chromatography method

Predominantly, the innate medicinal value of Cuscutae Semen has accounted for its extensive usage as a herbal remedy in China for centuries. Specifically, the broad applications of the medicine include aging inhibitors, anti-inflammatory agents, pain relievers, and aphrodisiacs. According to the records of crude Cuscutae Semen (CCS) and salt-processed Cuscutae Semen (PCS) in the Pharmacopoeia of the People’s Republic of China, the difference in the chemical composition between CCS and PCS is limited. In addition, an unprecedented high-performance thin-layer chromatography (HPTLC) method intended for the simultaneous quantitative determination of rutin, chlorogenic acid, hyperin, isoquercitrin, and astragalin in CCS and PCS was successfully developed. In order to achieve optimum separation, a mobile phase of ethyl acetate–formic acid–water–toluene (9:1:1:0.5, V/V) was cautiously integrated. Moreover, the densitometric determination method was executed at specified wavelengths for various standard compounds in refection/absorption mode. In particular, the calibration curves appeared to be linear in the range of 32.64–1139.19 ng per spot for rutin, 12.94–1048.36 ng per spot for chlorogenic acid, 13.71–1110.17 ng per spot for hyperin, 1.16–297.83 ng per spot for isoquercitrin, and 2.19–710.55 ng per spot for astragalin. The proposed method is simple, precise, specific, and accurate. The statistical analysis of the data obtained proves that the method is reproducible and selective, and can be used for the routine analysis of the reported compounds in CCS and PCS samples. This study could be benefit to investigate the processing mechanism of PCS as well as support their clinical applications.

     

广义Hamilton系统的研究概况

用广义Ｐｏｉｓｓｏｎ括号直接定义的广义Ｈａｍｉｌｔｏｎ系统是经典Ｈａｍｉｌｔｏｎ系统的一种推广。由于它的维数没有限制，同时它又保持了经典Ｈａｍｉｌｔｏｎ系统的主要性质，因此具有更大的普遍性和广泛的应用前景。本文简要介绍了广义Ｈａｍｉｌｔｏｎ系统理论的发展历史、基本概念和研究现状。