Insulating tubular BN sheathing on semiconducting nanowires

An effective method was developed for generation of insulating tubular boron nitride (BN)-sheathed nanostructures. ZnS nanowires and multilayered Si-SiO2 nanowires were successfully sheathed with insulating tubular BN-forming nanocables. Both the semiconductor nanowire cores and the BN sheaths are crystalline with well-uniform morphologies.     

C2型轴对称手性双恶唑啉的合成及其应用研究

本文综述了手性双恶唑啉的合成及其金属配合物作为手性催化剂在催化不对称反应中的应用研究进展。     

VO（Ⅱ）—组氨酸—π受体三元混配配合物的ESR波谱

钒的氨基酸配合物具有重要的生物和医学意义。VO(Ⅱ)-组氨酸配合物及VO(Ⅱ)-π受体二元配合物的ESR研究已有报道。但是VO(Ⅱ)-氨基酸-π受体三元配合物的结构及其ESR研究至今未见报道。本文考察了VOSO_4与组氨酸(His)和邻菲啰啉(Phen)及α,α′-联吡啶(bipy)三元体系在不同酸度(pH=1～14)的乙二醇/水(1:1)溶液中低温(173K)ESR波谱,获得了不同pH条件下配合情况的详细信息。     

重要生物微量元素和常见负电性元素在不同价态和电子组态下的轨道指数和电负性

本文用Xα方法计算出不同价态与电子组态下锰、铁、钴、铜、锌及钼等过渡族重要生物微量元素和氮、氧、氟、磷、硫、氯、硒和溴等常见负电性元素的数值原子轨道和轨道电负性值,再用数值拟合方法得出这些原子轨道的单ξ和双ξSlater型基函数的指数.研究了这些元素的原子所带电荷和电子组态对其原子轨道指数与轨道电负性的影响,给出了相应的回归公式.这些公式有较高的精确度,不但为研究这些元素化合物的电子结构提供基础参数,也为电荷自洽型的计算提供较可靠的计算公式.     

CuO-BaO/SiO2催化剂的结构表征

以XRD、XPS和EXAFS手段对CuO－BaO／Sic2催化剂及其还原态的结构进行了研究．结果表明，在CuO－BaO／SiO2体系中铜和钡都是以氧化态的形式存在，超细SiO2载体对所负载的CuO的结构有影响．随着样品负载量的逐渐降低，Cu－O和Cu－Cu睡的健长和配位数逐渐征小，而且低载量样品的健长和配位数减小的幅度最大．在总负载量＞13．39％的样品中，CuO以晶相的形式存在；总负载量＜13．39％的样品中，CUO呈现单层分布的高分出状态．还原态样品中钢以本价铜的形式存在，随负载量的降低，还原态Cu－Cu健的镇长和配位数也分别呈现出逐渐减小的趋势．还原态中心铜原子在催化剂表面的分布状态基本上保持了氧化态催化剂中CuO物相的分市状态．     

α-单取代环十二酮肟及缩氨基硫脲的合成及晶体结构

单晶X射线衍射分析表明, α-单取代环十二酮与氨衍生物羟胺和氨基硫脲发生缩合反应得到两种母体构象均为[3333], 而取代基为边外向或角反向的α-单取代环十二酮肟或缩氨基硫脲. 利用底物的“角位羰基参与反应”原理, “记忆效应”及进攻试剂与底物是否形成氢键解释了这一实验结果. 通常情况下, 试剂从空间障碍小的一面进攻羰基而生成α-角反取代环十二酮肟或缩氨基硫脲. 当试剂与底物的取代基之间能够形成分子间氢键时, 则生成α-边外取代环十二酮肟或缩氨基硫脲.     

PVC DISULFIDE AS CATHODE MATERIALS FOR SECONDARY LITHIUM BATTERIES

PVC disulfide (2SPVC) was synthesized by solution crosslink and its molecular structure was confirmed by infrared spectrum. 2SPVC's specific area is 36.1 m2·g-1 tested by stand BET method, and granularity experiment gives out the particle size of d0.5= 11.3μm. With SEM (Scanning Electron Microscope) experiment the surface morphology and particle shape of 2SPVC were observed. Cyclic voltammetry (scan rate: 0.5 mV·s-1) shows that 2SPVC experience an obvious S-S redox reaction in charge-discharge process. When 2SPVC was used as cathode material for secondary lithium battery in a 1 mol·L-1 solution of lithium bis(trifluoromethylsulfonyl) imide (Li(CF3SO2)2N) in a 5:45:50 volume ratio mixture of o-xylene (oxy), diglyme (DG) and dimethoxymethane (DME) at 30℃, the first discharge capacity of 2SPVC is about 400.3 mAh·g-1 which is very close to its theoretical value (410.5 mAh·g-1) at a constant discharge current of 15 mA·g-1. It can retain at about 346.1 mAh·g-1 of discharge capacity after 30 charge-discharge cycles. So 2SPVC is a very promising cathode candidate for rechargeable lithium batteries.     

One-step hexaplex immunoassays by on-line paper substrate-based electrospray ionization mass spectrometry for combined cancer biomarker screening

Mass spectrometry (MS) is attractive as a multiplexed immunoassay readout benefiting from its high sensitivity, speed and mass resolution. Here, a simple paper-based hexaplex immunoassay with an on-line MS readout was proposed, using functionalized paper as the immune substrates, along with rhodamine-based mass tags assembled on gold nanoparticles prepared as the mass probes (MPs). Simultaneous immune capture and labeling were conducted in one step on paper substrates in 96-well plates with a high throughput within 30 minutes, and the on-line efficient dissociation of the mass tags highly facilitated the hexaplex readout of the immune signals by a newly established on-line paper substrate-based electrospray ionization-MS setup. Six MPs were synthesized for the simultaneous quantification of six important cancer protein markers (cancer antigen 15-3, cancer antigen 19-9, carcinoma embryonic antigen, cancer antigen 125, human epididymis protein 4, and alpha fetoprotein) using only 10 μL serum, presenting satisfactory sensitivity, accuracy and specificity. This platform was further tested in screening for the six biomarkers in serum samples of patients with breast, liver and gastric cancers, showing its high potential for sensitive and specific early cancer diagnosis.

On-line paper substrate based electrospray ionization mass spectrometry for hexaplex immunoassays.     

Carbene-catalyzed enantioselective annulation of dinucleophilic hydrazones and bromoenals for access to aryl-dihydropyridazinones and related drugs

4,5-Dihydropyridazinones bearing an aryl substituent at the C6-position are important motifs in drug molecules. Herein, we developed an efficient protocol to access aryl-dihydropyridazinone molecules via carbene-catalyzed asymmetric annulation between dinucleophilic arylidene hydrazones and bromoenals. Key steps in this reaction include polarity-inversion of aryl aldehyde-derived hydrazones followed by chemo-selective reaction with enal-derived α,β-unsaturated acyl azolium intermediates. The aryl-dihydropyridazinone products accessed by our protocol can be readily transformed into drugs and bioactive molecules.

Polarity inversion of arylidene hydrazones to react with bromoenals via carbene organic catalysis is disclosed. The reaction enantioselectively affords 6-aryl-4,5-dihydropyridazinones and related drugs with proven commercial applications.     

Tuning cell adhesion on gradient poly(2-hydroxyethyl methacrylate)-grafted surfaces

A simple yet versatile method was developed to prepare a low-density polymerization initiator gradient, which was combined with surface-initiated atom transfer radical polymerization (ATRP) to produce a well-defined poly(2-hydroxyethyl methacrylate) (HEMA) gradient substrate. A smooth variation in film thickness was measured across the gradient, ranging from 20 A to over 80 A, but we observed a nonmonotonic variation in water contact angle. Fits of X-ray reflectivity profiles suggested that at the low graft density end, the polymer chain structure was in a "mushroom" regime, while the polymer chains at high graft density were in a "brush" regime. It was found that the "mushroom" region of the gradient could be made adhesive to cells by adsorbing adhesion proteins, and cell adhesion could be tuned by controlling the density of the polymer grafts. Fibroblasts were seeded on gradients precoated with fibronectin to test cellular responses to this novel substrate, but it was found that cell adhesion did not follow the expected trend; instead, saturated cell adhesion and spreading was found at the low grafting density region.