The stir-frying can reduce hepatorenal toxicity of Fructus Tribuli by inactivating β-glucosidase and inhibiting the conversion of furostanol saponins to spirostanol saponins

The purpose of this study was to illustrate the mechanism of “enzyme inactivation and toxicity reduction” of Fructus Tribuli (FT) after being heating processed. Ultra-high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) was used to quantitatively analyze the contents of four steroidal saponins in crude Fructus Tribuli (CFT) and stir-fried Fructus Tribuli (SFT) under different storage times at room temperature. The enzyme activity of β-D-glucosidase in CFT and SFT were determined and calculated by ultraviolet–visible spectrometry (UV-VIS spectrometry). In addition, the enzyme hydrolysates of FOT and tribuluside A were qualitatively analyzed by ultra-high-performance liquid chromatography coupled with quadruple-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS). The hepatorenal toxicity of spirostanol saponins in FT were further confirmed by in vivo and in vitro experiment. This study confirmed that “enzyme inactivation and toxicity reduction” was one of the reasons why the stir-frying can reduce hepatorenal toxicity of FT, and further enriched the exploration on the mechanism of processing toxicity reduction.     

苯并噻唑衍物的合成及结构-双光子吸收光物理特性关系

报道了三个具有典型A-π-A'型共轭结构的苯并噻唑衍生物的合成及结构-双光 子吸收光物理特性关系。通过对三个化合物的共轭结构增长和拉电子基强度变化对 化合物单光子荧光光谱、双光子诱导荧光光谱和双光子吸收截面等特性的影响研究 ，我们发现，苯并噻唑杂环中的杂原子硫在化合物共轭链链短时对其光物理特性影 响很强，在共轭链较长时影响减弱甚至消失。通常情况下，共轭链长度和拉电子基 强度共同对双光子吸收截面作贡献，我们的研究表明，当共轭链较长时，共轭链的 增长对增强分子双光子吸收截面的贡献远大于拉电子基强度变化的贡献。其中，新 化合物2（2-{4-[2-（4-硝基苯基）-乙烯基]苯基}-乙烯基）苯并噻唑具有双光子 吸收截面大(181*10~(-50)cm~4s/photon)和荧光量子产率高(13.8%)的特点，是双 光子荧光显微与成像应用的一个良好的候选材料。     

保护剂对K2PtCl6为前体合成纳米铂形状的影响

纳米粒子的性质不仅受到尺寸的影响，还与其形状密切相关，由于铂在催化及材料等领域中有重要应用，因此化学合成特定形状的纳米铂一直备受关注，具有特定表面结构的纳米粒子对于研究催化活性与表面原子结构的关系具有重要意义，目前立方体形状纳米铂已被合成，但高比例四面体形状纳米铂的合成研究很少有报道，     

Reactions of C5H5M (M = Fe, Ni) with substituted thiophenes

The ion molecule reactions between C₅H₅M⁺ (M = Fe, Ni) with some substituted thiophenes have been studied in an ion trap mass spectrometer. The reactions of halogen substituted thiophenes lead to the formation of a new C-C bond between the cyclopentadiene ring and the thiophene with the loss of a neutral HX. The reaction mechanism has been investigated by means of DFT calculations and it was found that the insertion of the metal atom in the C-X bond is the key step in the process.     

The Structures and Stability of HNOS Isomers

Potential energy surface of HNOS system is investigated by means of MP2 method with 6-311 G(d,p) basis set.The energy for each minimum and saddle point on the potential energy surface is corrected at the QCISD(T)/6-311 G(3df,2p) level of theory with zero-point vibrational energy included.As a result ,eighteen isomers are theoretically predicted and cis-HNSO is found to be global minimum on the potential energy surface,Wherein,fourteen isomers are considered as kinetically stable species,and should be experimentally observed.Comparisons are made for HNOS system with its analogues,HNO2 and NHS2.The nature of bonding and isomers‘ stability of HNOS system are similar to HNS2.The obvious similarities and discrepancies among HNOS,HNO2 and HNS2 are attributed to the hypervalent capacity of sulfur,oxygen and nitrogen atoms.     

Outer shell ionization potentials for ethane by a many-body Green's function method

A calculation based upon the many-body Green's function method is employed to obtain the outer shell vertical ionization potentials of the ethane molecule. An extended basis set is employed to represent the approximate optical potential, derived by the functional derivative approach, as well as the one-electron Green's function. The results obtained confirm a²E_g state for the ion arising from the first ionization process. Supported by a fellowship of the Scuola Normale Superiore.     

Classification of single-molecule surface-enhanced resonance Raman spectra of Rhodamine 6G from isolated Ag colloidal particles by principal component analysis

Surface enhanced resonance Raman (SERR) spectra of Rhodamine 6G are measured from single isolated Ag particles and analyzed by using a chemometrics technique, principal component analysis (PCA). The Ag particles are incubated with various amounts of R6G yielding the ratio of Ag particles to R6G molecules from 1:1 to 1:1000. Acquired SERR spectra are considered due to a single or very few R6G molecules. PCA is used to determine the number of chemically distinguishable species that contribute to the measured SERR spectra. A simple clustering tool, score bi-plot, is then inspected on grouping of the SERR spectra. The spectra are found to be largely similar except for the variability in the intensity and position of the bands that is believed to be correlated with the lifetime of the strong enhancement at specific places on an Ag surface. The spectra from four different Ag particles carrying more than 1000 R6G molecules are, however, unambiguously separated. Different aspects of the applied data analysis method and physicochemical perspective of the results are discussed.     

Mechanism of Romascone® release from hydrolyzed vinyl acetate nanoparticles: thermogravimetric method

The evaporation kinetics of pure Romascone® (methyl 2,2‐dimethyl‐6‐methylene‐1‐cyclohexanecarboxylate) and Romascone® when mixed with vinyl acetate (VAc) nanoparticles have been determined by using thermogravimetric analysis. For pure Romascone®, the evaporation rate follows an Arrhenius dependence with temperature. When Romascone® is mixed with VAc nanoparticles, two evaporation mechanisms are identified depending on the presence of comonomer and crosslinking degree. (a) Evaporation limited by the presence of non‐interactive nanoparticles. The evaporation rate is governed by the evolution of the equilibrium vapor pressure that depends on the volume fraction of volatile molecules. (b) Evaporation limited by the diffusion of volatile molecules through a polymeric particle wall. Since the diffusion depends on the physical state or structure of the polymeric nanoparticle phase, the volume fraction of volatile molecules is a determinant parameter. Furthermore, a sudden modification in the evolution of the diffusion coefficient with volatile volume fraction gives rise to discussion on phase transition. Copyright © 2006 John Wiley & Sons, Ltd.     

OCS分子基态(X3A'''')的势能函数

应用群论及原子分子反应静力学方法推导了OCS分子的电子态及其离解极限,采用B3P86方法,在CC-PVTZ水平上,优化出OCS基态分子稳定构型为三重态的Cs构型,其平衡核间距RC-S=0.1768nm、RC-O=0.1179nm、∠OCS=122.9,°能量为-512.0405 a.u.。同时计算出基态的简正振动频率:对称伸缩振动频率ν(A′)=354.5cm-1,弯曲振动频率ν(A′)=633.5cm-1和反对称伸缩振动频率ν(A′)=1792.8cm-1。在此基础上,使用多体项展式理论方法,导出了基态OCS分子的全空间解析势能函数,该势能函数准确再现了OCS(Cs)平衡结构。     

硫氧还蛋白还原酶结构分形研究

提出并应用改进的分形方法对硫氧还蛋白还原酶(TrxR)结构进行研究。建立了适用于TrxR的分形及数据处理方法。发现正常的TrxR的结构分维值约为1.33,氧化后结构分维值增大。提出了蛋白质结构分维值是表征蛋白质分子状态的重要特征之一的观点,并结合TrxR验证了该观点。提出了药物分子分维值应与靶酶的结构分维值相契合的观点,并结合以TrxR为靶点的药物研发实验验证了该观点。