An infrared study on Langmuir-Blodgett films of octadecylammonium octadecanoate: FWHM and the vibrational coupling

The monolayer of the mixture of octadecanoic acid and octadecylamine with molar ratio 1: 1 has been investigated at the air-water interface. It was found that the monolayer shows a rather stable state at the surface pressure of 30 mN/m and this monolayer can be transferred onto a CaF2 plate by Langmuir-Blodgett (LB) technique. The infrared spectra of LB films indicated that octadecyl ammonium octadecanoate is formed by an intermolecular proton exchange between adjacent carboxylic and aminic groups (COO- and NH3+). In three-layer LB film, the CH2 scissoring mode of the long hydrocarbon chains of octadecyl ammonium octadecanoate shows a broad band feature at about 1468 cm(-1) while this vibrational mode of three-layer LB film of the mixture (1: 1) of deuterated stearic acid and octadecylamine (octadecylammonium octadecanoate-d35, C18H37NH3+C17D35COO-) only shows a narrow band. The broad feature of the CH2 scissoring mode in octadecylammonium octadecanoate probably originates from the coupling between the chain of stearic acid and that of octadecylamine while this kind of coupling could be completely removed in octadecylammonium octadecanoate-d35.

Low-density polyethylene superhydrophobic surface by control of its crystallization behavior

A simple and inexpensive method for forming a low-density polyethylene (LDPE) superhydrophobic surface by controlling the crystallization behavior of LDPE by adjusting the crystallization time and nucleation rate has been proposed. The resulting porous surface, with hierarchical micro- and nanostructures on the beautiful floral designs, has a water contact angle of 173.0degrees +/- 2.5degrees.

TiO2-SnO2复合凝胶的水-乙醇蒸汽吸附动力学研究

中国科学院山西煤炭化学研究所

溶液pH对硫堇与DNA相互作用方式的影响

用电化学和光谱方法研究了溶液pH对硫堇(TH)与小牛胸腺脱氧核糖核酸(CT-DNA)相互作用方式的影响。电化学测量结果表明,在pH 7.2的磷酸盐缓冲溶液中,TH与CT-DNA之间的作用方式以嵌入结合为主,在pH6.5的磷酸盐缓冲溶液中,TH与CT-DNA之间的作用方式既存在嵌入结合也存在静电作用。荧光光谱测量结果表明,TH与DNA结合后其荧光发生猝灭,通过Stern-Volmer方程计算得到pH 6.5时TH-DNA体系的猝灭常数高于pH 7.2时的值,表明在pH 6.5的溶液中两者相互作用更强。圆二色谱(CD)实验结果也证实了这一结论。

Computer simulation of human iodothyronine deiodinase single-chain antibody

Iodothyronine plays a major role in growth, basic metabolism and organ formation. It has an extremely limited source in the body. In this thesis, we designed iodothyronine(T4) as hapten. Then a single chain antibody displayed on phange was obtained from a human phage displaying a single chain antibody library. The specific genes of E3 was subcloned in P-5E vector. According to its amino acid sequences, we simulate its three dimention structure by computer. It has never been reported in PDB.

Enhanced surface plasmon resonance immunoassay for human complement factor 4

Using an enhanced surface plasmon resonance (SPR) immunosensor, we have determined the concentration of human complement factor 4 (C4). Antibody protein was concentrated into a carboxymethyldextran-modified gold surface by electrostatic attraction force and a simultaneous covalent immobilization of antibody based on amine coupling reaction took place. The sandwich method was applied to enhance the response signal and the specificity of antigen binding assay. The antibody immobilized surface had good response to C4 in the range of 0.02-20 mug/ml by this enhanced immunoassay. The regeneration effect by pH 2 glycine-HC1 buffer was also investigated. The same antibody immobilized surface could be used more than 80 cycles of C4 binding and regeneration. In addition, the ability to determinate C4 directly from serum sample without any purification was investigated. The sensitivity, specificity and reproducibility of the enhanced immunoassay are satisfactory. The results clearly demonstrate the advantages of the enhanced SPR technique for C4 immunoassay.

Eu~(2+)掺杂硼酸盐系列发光晶体化学键参数的计算

利用复杂晶体化学键理论对Eu2 +掺杂的硼酸盐晶体Ba2 LiB5 O10 ,Ba2 MgB2 O6 ,Ba2 Be2 B2 O6 ,BaLiBO3,SrB4 O7和SrAl2 B2 O7的化学键参数进行了理论计算 .结果表明 ,在不同的晶体中掺杂离子与配位原子间形成的共价键的键性是不同的 ,这种差异的产生是由于成键原子的性质、配位数以及键长的不同而造成的.

人源化甲状腺素脱碘酶单链抗体的结构模拟

以四碘甲状腺素原氨酸为半抗原 ,从人噬菌体展示半合成单链抗体库中筛选与半抗原有特异结合性的单链抗体 E3 ,并测定了 E3的一级结构 ,同时用计算机模拟了其空间结构

乙酰丙酮铜杂化层状磷酸钒的合成与表征

本文主要报道一种可用于含过渡金属层状VOP化合物的直接合成方法和用该方法合成的一个新层状乙酰丙酮铜配合物嵌入的磷酸钒(Cu(acac)<,2>-LVPO),并对其进行了结构表征.

Electrochemistry and spectroscopy study on the interaction of microperoxidase-11 with lipid membrane

The interaction of microperoxidase-11 (MP11) with cationic lipid vesicles of didodecyldimethylammonium bromide (DDAB) induces an alpha -helical conformation from random coil conformations in solution and this change then makes heme macrocycle more distorted. DDAB-induced MP11 conformations were investigated by cyclic votammetry (CV), circular dichroism (CD) and UV-vis spectrometry. All results indicate that the binding of MP11 in solution to DDAB vesicles and the ordered structure formation are driven by mostly electrostatic interaction between negatively charged residues in the undecapeptide and positively charged lipid headgroups on the membrane surface. Upon binding to DDAB, its half-peak potential was also changed. The mechanism of the interaction between MP11 and DDAB was also discussed. (C) 2001 Elsevier Science B.V. All rights reserved.

Hydrothermal synthesis and crystal structure of [{Cu(2,2 '-bpy)(2)}(2)Mo8O26]: a beta-octamolybdate cluster covalently bonded to two {Cu(2,2 '-bpy)(2)}(2+) coordination complexes via bridging oxo groups

An organic-inorganic hybrid solid, (Cu(2,2'-bpy)(2))(2)Mo8O26, has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Dark green crystals crystallize in the orthorhombic system, space group Pna21, a = 24.164(5), b = 18.281(4), c = 11.877(2) Angstrom, alpha = 90 degrees, beta = 90 degrees, gamma = 90 degrees, V= 5247(2) Angstrom (3), Z = 4, lambda (MoK alpha) = 0.71073 Angstrom (R(F) = 0.0331 for 5353 reflections). Data were collected on a Siemens P4 four-circle diffractometer at 293 K in the range 1.69 degrees < theta < 25.04 degrees using the omega -scan technique. The structure was solved by the direct method and refined by full-matrix least squares on F-2 using SHELXL-93. The structure of this compound consists of discrete (Cu(2,2'-bpy)(2))(2)Mo8O26 clusters, constructed from beta -octamolybdate subunits ((Mo8O26)(4-)) covalently bonded to two (Cu(2,2'-bpy)(2))(2+) coordination complexes via bridging oxo groups that connect two adjacent molybdenum sites. (C) 2001 Academic Press.

Bond covalencies in R2BaCuO5 (R = Sm, Gd, Dy, Ho, Y, Er, Tm, Yb, Lu)

Bond covalencies in R2BaCuO5 (R = Sm, Gd, Dy, Ho, Y, Er, Tm, Yb, Lu) were calculated by means of a semiempirical method. This method is the generalization of the dielectric description theory of Phillips-Van Vechten-Levine-Tanaka scheme. The present paper presents the formula concerning the decomposing of complex crystals which are usually anisotropic systems into the sum of binary crystals which are isotropic systems. It can be seen that although the bond covalency is related to many physical quantities, it is mainly influenced by bond valence or bond charge, and a higher bond valence will produce higher bond covalency.

Monte Carlo simulation of phase separation of A/B/A-B ternary mixtures

Monte Carlo simulations were used to model A/B/A-B ternary mixtures with different AB diblock copolymer volume fractions for which both the dispersed and continuous phase volume fractions were kept constant. For concentrations of the diblock copolymer below a critical value, the domain size increment of the dispersed phase decreases linearly with the copolymer concentration. This is in agreement with the predictions of Noolandi and Hong. The dependence of the domain size as a function of the copolymer volume fraction can also be fitted by the equation of Tang and Huang. Our simulations indicate, for the first time, that the micelles form before saturation of the interface occurs. This means that the formation of the micelles is not a result of the saturation of the interface.

The electrochemical behavior of polypyrrole from self-assembly polymerization

The electrochemical behavior and the charge transport of polypyrrole film prepared by self-assembly polymerization have been investigated. Ir is found that the microstructure of the film influences the electrochemical behavior of polypyrrole, and that the p-toluenesulfate (Tos(-)) ion plays avery important role in this system.