Synthesis of Novel Dendrimers Containing Amino Acids and Peptides

Dendrimers are known for their well-defined, regular, highly branched architectures with a large number of functional groups1. Recently, dendrimers have been widely researched in different fields, such as molecular light havesting, catalysts, liquid cryst…     

Self-assembled multivalent vancomycin on cell surfaces against vancomycin-resistant enterococci (VRE)

A vancomycin (Van) derivative self-assembles in a phosphate buffer as a divalent Van and on cell surfaces as a multivalent Van, which offers potent activity against VRE.     

邻菲啰啉对固定尿酸酶催化反应动力学的影响

The activation energy of the enzyme-catalyzed reaction for uric acid decreases markedly in the presence of o-phenanthroline, which activates the bioelectrochemicla activity of the polypyrrole uricase electrode. The response current of the enzyme electrodeis independent of the concentration of o-phenanthroline. Based on the experimental results, the mechamsm of the enzyme-catalyzed reaction for uric acid in the presence of o-phenanthroline is presented as follows: E+A→EA, EA+S EAS, EAS→EA+P, where E, A, S and P are the enzyme, activator, substrate and product, respectively. The effects of pH value, potential and the uric acid concentration on the response currents of the uricase electrode have been studied in the presence of o-phenanthroline. In the presence of o-phenanthroline, the response current of the enzyme electrode increase linearly with increasing concentration of uric acid in the region of 0.07 to 0.67 mmol·L~(-1), therefore the polypyrrole uricase electrode which has once lost its activity can be activated and used again to determine the substrate concentration.     

Effect of photothermal therapy on breast tumor vascular contents: noninvasive monitoring by near-infrared spectroscopy

The goal of this study was to investigate the effect of photothermal laser irradiation on rat breast tumor (DMBA-4) vascular contents. An 805-nm diode laser was used in our experiment with a power density ranging from 0.32 to 1.27 W/cm2. The dynamic changes of oxygenated hemoglobin and total hemoglobin concentrations, delta[HbO2] and delta[Hb]total, in rat tumors during photothermal irradiation were noninvasively monitored by a near-infrared spectroscopy system. A multichannel thermal detection system was also used simultaneously to record temperatures at different locations within the tumors. Our experimental results showed that: (1) photoirradiation did have the ability to induce hyperthermic effects inside the rat breast tumors in a single exponential trend; (2) the significant changes (P < 0.005) of delta[HbO2] and delta[Hb]total in response to a low dosage of laser irradiation (0.32 W/cm2) have a single exponential increasing trend, similar to that seen in the tumor interior temperature; and (3) the increase in magnitude of delta[HbO2] is nearly two times greater than that of delta[Hb]total, suggesting that photoirradiation may enhance tumor vascular oxygenation. The last observation may be important to reveal the hidden mechanism of photoirradiation on tumors, leading to improvement of tumor treatment efficiency.     

Determination of the double-bond position in hexadecenols by mass spectrometry without prior chemical modification

Fourteen isomers of chemically unmodified hexadecenol were analysed by two types of quadrupole mass spectrometer, coupled with a gas chromatograph, for the location of the double-bond position. A series of spectra were interpreted in terms of mass spectral patterns on a fuzzy classification, in which the intensity ratios of six diagnostic pairs of the predominant ions were preferred in devising similarity indices. The accuracy of the method in the location of double-bond position was confirmed by testing with other series of spectra.     

聚邻甲苯胺的合成及物理化学性质

聚苯胺的导电性和电化学特性已被广泛地研究。最近,对苯胺衍生物的聚合物也开始了研究,如聚邻甲氧基苯胺、聚邻苯二胺和聚邻氨基酚,其中聚邻甲氧基苯胺是一种可溶性的导电高分子材料。为了探讨苯胺聚合的机理和苯胺上不同基团对聚苯胺性质的影响,我们使用了十六种苯     

Preparation of [5,6]- and [6,6]-oxahomofullerene derivatives and their interconversion by Lewis acid assisted reactions of fullerene mixed peroxides

[60]Fullerene mixed peroxides C60(O)(OOtBu)4 exhibit chemo- and regioselective reactions under mild conditions. The epoxy moiety is opened by ferric chloride to form vicinal hydroxy chloride C60Cl(OH)(OOtBu)4. BF3 is also effective in opening the epoxy moiety. The O-O bond of the fullerene mixed peroxide is cleaved by aluminum chloride to form both [5,6]- and [6,6]-fullerene hemiketals (oxohomo[60]fullerenes). A Hock-type rearrangement is proposed for the formation of the hemiketals, in which a fullerene C-C bond is cleaved. Lewis acids and/or visible light can initiate isomerization of the hemiketal isomers. Single-crystal X-ray analysis and theoretical calculations confirmed the results.     

一类新的毛细管气相色谱固定液—侧链液晶冠醚聚硅氧烷的研究

合成了一种新的毛细管气相色谱用固定液——侧链含冠醚液晶的聚硅氧烷,这种固定液易于涂渍在弹性石英毛细管柱上,柱效高,热稳定性好,极性中等,它具有高分子液晶和高分子冠醚固定液的双重保留性能,适于分离多种异构体。     

取代金刚烷的异构体计数

采用图论方法对单一种取代基取代的金刚烷和烷基取代的金刚烷构型、手性构型和非手性构型数进行了计算,结果分别以母函数形式和表格形式给出。     

Hypergraph Turán Numbers of Vertex Disjoint Cycles

The Turán number of a k-uniform hypergraph H,denoted by ex_k(n;H),is the maximum number of edges in any k-uniform hypergraph F on n vertices which does not contain H as a subgraph.Let C_l~((k)) denote the family of all k-uniform minimal cycles of length l;S(?₁,…,?_r) denote the family of hypergraphs consisting of unions of r vertex disjoint minimal cycles of length ?₁,…?_r,respectively,and C_l~((k))denote a k-uniform linear ...