锂离子选择性微电极在生物体液中的响应

最近几年已报道了几种锂离子选择性电极.本文作者曾研制了以苯基膦酸二辛酯(DOPP)为溶剂,四苯硼酸盐为活性物质的PVC膜锂离子选择电极.本文在此基础上研制了锂离子选择性微电极,比较了以四苯硼酸钾(KTPB)及四苯硼酸钠(NaTPB)为活性物质的锂微电极的性能.同时考察了微电极在细胞内液、血清及生理盐液中对锂离子的响应特性.     

基于聚合诱导自组装制备二氧化硅/聚合物纳米复合材料

纳米二氧化硅(SiO2)颗粒以其高硬度、高比表面积、高稳定、价格合理等优势被广泛应用于复合材料的制备中,获得的SiO2/聚合物复合材料通常具有优良的机械性能、很好的热稳定性以及增强的光学和电性能.近年来,随着聚合诱导自组装(PISA)的提出与发展,研究者们基于PISA发展了多种制备不同形貌聚合物纳米粒子的简便方法,为制...     

Ion Pairing Kinetics Does not Necessarily Follow the Eigen-Tamm Mechanism

The most recognized and employed model of the solvation equilibration in the ionic solutions was proposed by Eigen and Tamm, in which there are four major states for an ion pair in the solution： the completely solvated state, 2SIP （double solvent separate ion pair）, SIP （single solvent separate ion pair）, and CIP （contact ion pair）. Eigen and Tamm suggested that the transition from SIP to CIP is always the slowest step during the whole pairing process, due to a high free energy barrier between these two states. We carried out a series of potential of mean force calculations to study the pairing free energy profiles of two sets of model mono- atomic 1：1 ion pairs 2.0：x and x：2.0. For 2.0：x pairs the free energy barrier between the SIP and CIP states is largely reduced due to the salvation shell water structure. For these pairs the SIP to CIP transition is thus not the slowest step in the ion pair formation course. This is a deviation from the Eigen-Tamm model.     

Preparation of Helical Mesoporous Ethenylene-silica Nanofibers with Lamellar Mesopores on Their Surface

The morphologies and pore architectures of mesoporous ethenylene‐silica were controlled using cetyltrimethylammonium bromide (CTAB) as template and (S)‐β‐citronellol as a co‐structure‐directing agent under basic conditions. When the (S)‐β‐citronellol/CTAB molar ratios are in the range of 0.75–2.0, helical nanofibers were obtained. With increasing the (S)‐β‐citronellol/CTAB molar ratio, the lengths of the nanofibers increases. Lamellar mesopores were identified on the surfaces of the nanofibers prepared in the (S)‐β‐citronellol/CTAB molar ratio range of 1.5–2.0. At the (S)‐β‐citronellol/CTAB molar ratio of 2.5:1, nanoparticles with nanoflakes on the surfaces were obtained. The field emission scanning electron microscopy images taken after different reaction times indicated that the helical pitches of the nanofibers decreased with increasing the reaction time. Helical 1,4‐phenylene‐silica and methylene‐silica nanofibers were also prepared. The results indicated that the morphologies and pore architectures of the obtained organic‐inorganic hybrid silicas are also sensitive to the hybrid silica precursors. Helical ethenylene‐silica nanofibers with lamellar mesopores on their surfaces can be also prepared using the mixtures of CTAB and racemic citronellol within a narrower citronellol/CTAB molar ratio range.     

Fluorescence assay for monitoring Zn-deficient superoxide dismutase in vitro

A method has been developed for selective detection of the zinc-deficient form of Cu, Zn superoxide dismutase (SOD1) in vitro. Zinc-deficient SOD1 mutants have been implicated in the death of motor neurons leading in amyotrophic lateral sclerosis (ALS or Lou Gerhig's disease). Thus, this method may have applicability for detecting zinc-deficient SOD1 mutants in human ALS patients samples as well as in a transgenic mouse model of ALS and in cultured motor neurons. We determined previously that structural analogs of 1,10 phenanthroline, which react specifically with Cu(I), react with the active Cu(I) of SOD1 when zinc is absent, but not when zinc is also bound, as evidenced by the fact that the reaction is inhibited by pretreatment of the enzyme with zinc. We report herein that bathocuproine, or its water-soluble derivative bathocuproine disulfonate, react with zinc-deficient SOD1 to form a complex which fluoresces at 734 nm when excited at 482 nm. Fluorescent intensity is concentration dependent, thus we propose to use fluorescent confocal microscopy to measure intracellular levels of zinc-deficient SOD1 in situ.     

In Situ Observation of Dynamic Galvanic Replacement Reactions in Twinned Metallic Nanowires by Liquid Cell Transmission Electron Microscopy

Galvanic replacement is a versatile approach to prepare hollow nanostructures with controllable morphology and elemental composition. The primary issue is to identify its fundamental mechanism. In this study, in situ liquid cell transmission electron microscopy was employed to monitor the dynamic reaction process and to explore the mechanism of galvanic replacement. The detailed reaction process was revealed based on in situ experiments in which small Au particles first appeared around Ag nanowires; they coalesced, grew, and adhered to Ag nanowires. After that, small pits grew from the edge of Ag nanowires to form tubular structures, and then extended along the Ag nanowires to obtain hollowed structures. All of our experimental observations from the viewpoint of electron microscopy, combined with DFT calculations, contribute towards an in‐depth understanding of the galvanic replacement reaction process and the design of new materials with hollow structures.     

载气流速对高场不对称波形离子迁移谱的影响

载气流速是影响高场不对称波形离子迁移谱(FAIMS)的重要参数.以自制的高场不对称波形离子迁移谱仪为实验平台,在射频电场幅值3 kV/cm,频率500 kHz,占空比0.36的条件下,研究了载气流速对苯离子迁移谱谱峰强度和半峰宽的影响.实验结果表明: 载气流速为3.7 L/min时,苯样品的谱峰强度最大,仪器的灵敏度最高.随着载气流速的增加,谱峰半峰宽变宽,仪器的分辨率下降.载气流速为3 .0～3.7 L/min时仪器综合性能最佳.此结果对于控制迁移谱仪载气流速有重要的参考意义.     

Synthesis, spectroscopic and electrochemical property of an unsymmetrical porphyrin and its Zn compound

<正>In this article,a new 5-(p-maleicaminophenyl)-10,15,20-triphenylporphyrin(H_2P) and relative zinc compound(ZnP) were synthesized and characterized by means of elemental analyses,UV-vis,IR,MS and ~1H NMR spectroscopies.Furthermore,we have investigated the fluorescence spectroscopy of these compounds.The oxidation and reduction properties of the compounds were studied by the cyclic voltarnmetry,the oxidation-reduction potentials were obtained.     

C-C bond cleavage of acetonitrile by a dinuclear copper(II) cryptate

The dinuclear copper(II) cryptate [Cu2L](ClO4)4 (1) cleaves the C-C bond of acetonitrile at room temperature to produce a cyanide bridged complex of [Cu2L(CN)](ClO4)3.2CH3CN.4H2O (2). The cleavage mechanism is presented on the basis of the results of the crystal structure of 2, electronic absorption spectra, ESI-MS spectroscopy, and GC spectra of 1, respectively.