荧光法研究牛血清白蛋白与中性红的相互作用

用荧光光谱、同步荧光光谱、三维荧光光谱和吸收光谱研究了牛血清白蛋白与中性红的结合反应特征,用Stern-Volmer方程和Lineweaver-Burk双倒数函数方程等处理实验数据,得到了15℃时动态猝灭常数kq=5.434×1012L.mol-1.s-1;静态猝灭结合常数KLB=3.300×104L.mol-1,结合位点数n=1.18,根据F ster能量转移原理计算出中性红在牛血清白蛋白上的结合距离r=2.63 nm。     

First total syntheses of (+)-7-deoxynogarol and (+)-7-con-o-methylnogarol

The first total syntheses of (+)-7-deoxynogarol (2) and (+)-7-con-O-methylnogarol (3), the notable members of nogalamycin congeners, were achieved employing the Diels-Alder reaction of the highly functionalized dienes (11 and 20) with the (+)-naphthoquinone (6), the CDEF-ring system of nogalamycin congeners, as a key synthetic step.     

Heteropolyanions as oxidation catalysts in a 2-phases system

Described is a system using heteropoly-11-tungstates as homogeneous catalysts for the oxidation of cyclohexene with hydrogen peroxide. The catalyst is dissolved in an organic solvent while the oxidant resides in the aqueous phase. The efficiency is high.     

Photosensitized single electron transfer initiated N-debenzylation. A convenient and mild approach

A mild method of N-debenzylation via photosensitized single electron transfer (SET) using 9, 10-dicyano anthracene (DCA) as electron acceptor in neutral medium is reported.     

碱土金属X（X=Be，Mg，Ca和Sr）掺杂二维SnS2材料的第一性原理研究

基于密度泛函理论的第一性原理研究赝势平面波方法,计算了碱土金属X(X=Be, Mg, Ca和Sr)掺杂二维单层SnS₂的电子结构、磁学性质和光学性质.结果表明：S-rich条件下的体系相较于Sn-rich更稳定,能带结构表明：在Be掺杂后,SnS₂体系从自旋向上通道和自旋向下通道完全对称的非磁性半导体转变为具有1.999μ_B磁矩的磁性半导体.在Mg掺杂后,体系转变为非磁性P型半导体;Ca和Sr两种掺杂体系由于极化程度的不同,导致在下自旋通道的能带穿过费米能级,而在上自旋通道的能带并未穿过费米能级,呈现出磁矩分别为1.973、2.000μ_B的半金属特性.同时发现X(X=Be, Mg, Ca和Sr)掺杂后,掺杂体系实部静态介电常数大幅度增加,掺杂后的SnS₂体系的极化能力增强,虚部数值在低能区明显变大,更适用于长波长光电器. Be, Mg, Ca和Sr掺杂不仅导致吸收边红移,而且提高了红外光区域的有效利用率.     

基于有机溶剂原位制备的致密疏水铜金属层在保护锌负极中的应用

通过在 N-甲基吡咯烷酮(NMP)有机溶剂中锌电极与 CuI之间的置换反应,在锌电极上原位构建了一层致密且疏水的铜金属保护层(Cu@Zn)。铜金属保护层能有效地隔离锌电极与电解液的接触,减少锌电极-电解液界面的析氢和腐蚀等副反应。同时,铜金属保护层还具有较好的亲锌性,更小的界面电阻,更低的成核能垒,有利于锌离子均匀沉积,从而有效抑制了锌枝晶的生成。Cu@Zn对称电池实现了超过 1 700 h(1 mA·cm^-2)和 1 330 h(3 mA·cm^-2)的循环寿命。采用商用 MnO₂与之匹配得到的Cu@Zn||MnO₂全电池不仅在1 A·g^-1下具有168.5 mAh·g^-1的可逆比容量,还可稳定循环2 000次以上。     

The pure rotational raman spectrum of pyrazine C4H4N2

The pure rotational Raman spectrum of pyrazine, C₄H₄N₂, has been observed for the first time. The spectrum was recorded photographically using a 3 m spectrograph with a reciprocal linear dispersion of 1.4 cm⁻¹ mm⁻¹. The following rotational constants were obtained:

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The S21 lines of the A2Σ+ (v′ = 1)←X2Π (v″ = 0) transitions of OH and OD

The S₂₁ lines of the OH radical for the A²Σ⁺ (v′ = 1)←X²Π (v″ = 0) transition have been observed in the 278–280 nm region from the laser-excitation spectrum. The OH radical was generated from either the H + NO₂ or the H + O₃ reaction in a flow system and the fluorescence passing through a 309.6 nm interference filter was detected with a photomultiplier-boxcar integrator arrangement. The weak S₂₁ lines were observed at laser energies above 0.2 mJ. The observed peak wavenumbers are in excellent agreement with those predicted for the S₂₁ bands of the A (v>′ = 1)←X (v″ = 0) transition from the known spectroscopic parameters. Observation of the corresponding S₂₁ system for OD in the 286.0–286.9 nm region further confirms this assignment. The relative absorption cross-sections of about one-tenth those of the P₁ lines are in good agreement with theoretical considerations.     

Chemical profiling and quantification of multiple components in Jin-Gu-Lian capsule using a multivariate data processing approach based on UHPLC-Orbitrap Exploris 240 MS and UHPLC-MS/MS

The Jin-Gu-Lian capsule, a Chinese Miao herbal compound, is widely used to treat rheumatoid arthritis. In this study, a rapid, selective, and sensitive UHPLC-Orbitrap Exploris 240 MS method was developed to analyze the chemical composition of Jin-Gu-Lian capsules. A total of 88 compounds were identified, including 23 flavonoids, 23 organic acids, 14 phenylpropanoids, 12 phenols, eight alkaloids, four terpenes, three quinones, and one ketone. Among these, 21 compounds were clearly detected based on a comparison with reference standards and selected as quality control markers. Thereafter, these compounds were simultaneously determined in the Jin-Gu-Lian capsules. The established method was successfully validated and applied for the simultaneous determination of 21 biologically active compounds in Jin-Gu-Lian capsules of 27 sample batches. Quantitative data of the analytes were analyzed using multivariate statistical analysis to determine the quality of the Jin-Gu-Lian capsules. Four compounds (JGLC6 [salidroside], JGLC8 [chlorogenic acid], JGLC12 [liriodendrin], JGLC19 [quercetin]) were identified as chemical markers for quality control of Jin-Gu-Lian capsules. Altogether, the established method was validated as a novel and efficient tool, that can be used for rapid analysis of Jin-Gu-Lian capsules. Accordingly, this study serves as a reference for scientific research on traditional Chinese and ethnic medicine.