A highly sensitive and rapid assay for protein determination in human urine and penicillin using a Rayleigh light-scattering technique with benzeneazo-8-acetylamino-1-naphthol-3,6-disulfonic acid sodium salt.

A simple and sensitive method was conducted for the determination of trace amounts of proteins with benzeneazo-8-acetylamino-1-naphthol-3,6-disulfonic acid sodium salt (azophloxine, AP) using a Rayleigh light-scattering (RLS) technique. At pH 2.60 and in the presence of an emulsifier OP microemulsion, the RLS of AP can be greatly enhanced by proteins, owing to the interaction between AP and protein. The enhanced intensity is proportional to the concentration of proteins. Four proteins, including bovine serum albumin (BSA), human serum albumin (HSA), lysozyme (Lys) and gamma globulin (gamma-G) have been tested. For example, the linear range of BSA was 0 - 0.06 microg mL(-1) with detection limits of 2.38 ng mL(-1). The method was applied to the analysis of protein in human urine and penicillin samples with satisfactory results. The relative standard deviation was in all instances less than 4.0%, and the recovery was in the range of 97.5 - 104%.     

Differentiation of chiral phosphorus enantiomers by P and H NMR spectroscopy using amino acid derivatives as chemical solvating agents

The ability of commercially available amino acid derivatives, especially Fmoc-Trp(Boc)-OH, to differentiate enantiomers of chiral phosphonates, phosphinates, phosphates, phosphine oxides, and phosphonamidates is demonstrated with (31)P, (13)C, and (1)H NMR spectroscopy. The chiral differentiation provided a rapid and convenient method for measuring the enantiomeric purity of these phosphorus compounds.     

Asymmetric synthesis XXVII: Asymmetric catalytic trimethylsilylcyanation of aldehydes by novel Ti-chiral Schiff base complexes

Enantioselective catalytic trimethylsilylcyanations of aldehydes with 48% to 92% e.e. have been studied using the novel Ti-chiral Schiff base complexes. We have found that the catalyst led to high enantoselectivity when the molar ratio of the Schiff base 1 to Ti(O-i-Pr)₄ was 2:1.     

韧性金属裂纹尖端损伤区内应变场测量——数字散斑相关法应用

本文用数字散斑相关方法测量了五种不同幂硬化指数韧性金属材料(铝和铜),双边裂纹尖端细观区域内应变场.对所得结果用韧性损伤模型进行了分析.在此法中以金属自然表面结构为散斑场,不同加载状态的散斑场进行比较,得到相对变形与应变.图象之间相关性 C 是变形参数或是位移及其导数的泛函.使其相关性 C 取最大值的试凑变形即为其真实变形场.这一方法在细观测量中应用得到满意的结果.     

Electronic properties of polyoxometalates: a DFT study of alpha/beta-[XM(12)O(40)](n-) relative stability (M=W, Mo and X a main group element)

Keggin heteropolyanions [XM(12)O(40)](n-) have various isomeric structures, alpha and beta being the most common. Conventionally, the alpha structure appears to be the most stable, but calculations carried out at the DFT level for X = P(V), Si(IV), Al(III), As(V), Ge(IV), and Ga(III) and M = W(VI) and Mo(VI) show that this stability depends on several factors, particularly on the nature of the heteroatom (X) and the total charge of the cluster. In this paper, we apply the clathrate model to the Keggin molecule to carry out a fragment-interaction study to elucidate when and why the traditional relative stability of various isomers can be inverted. The fully oxidized anions that have inverted the traditional stability trend in this series are [AlW(12)O(40)](5-) and [GaW(12)O(40)](5-), both of which contain a third-group heteroatom and an overall charge of -5. beta-isomers are always more easily reduced than alpha-isomers. This experimental observation suggests that reduction favors the stability of beta-isomers and one of the most important results of this study is that the alpha/beta inversion is achieved in most cases after the second reduction. The alpha- and beta-isomers may have different properties because the energy of the LUMO, a symmetry-adapted d(xy)-metal orbital, is different.     

Preparation of AgBiVMoO/-Al2O3 Catalysts for the Partial Oxidation of Propane

A novel mixed sol method was developed for the preparation of supported catalysts. Analyses by means of XRD and BET show that a 40%AgBiVMoO/γ-Al2O3 catalyst prepared by this method possessed high specific surface area and high dispersion of the active phase. As a result, high acrylic acid selectivity of 8.5% was obtained when the catalyst was used in the reaction of propane partial oxidation to acrylic acid in a fixed-bed reactor.     

石墨炉原子吸收光谱法直接测定血样中硒

用石墨炉原子吸收光谱法，以硝酸铜和硝酸铵为基体改进剂，塞曼效应扣背景，采用标准加入法可直接测定血样中硒，回收率为95％～105％，相对标准偏差为5．8％，检出限为96pg，测定结果准确可靠。     

Terminally functionalized polyisobutylene oligomers as soluble supports in catalysis

A new phase selective hydrocarbon soluble polymer support is described.