Ultrafast Dynamics of o‐Bromofluorobenzene Studied by Time‐Resolved Photoelectron Imaging

Photodissociation dynamics and rotational wave packet coherences of o‐bromofluorobenzene are studied by femtosecond time‐resolved photoelectron imaging (see figure). The decay of different photoelectron rings shows the population decay of states from which the lifetimes of different states are determined. The variation of photoelectron angular distributions reflects the evolution of rotational coherences.

     

Characterization of porcine skin as a model for human skin studies using infrared spectroscopic imaging

Porcine skin is often considered a substitute for human skin based on morphological and functional data, for example, for transdermal drug diffusion studies. A chemical, structural and temporal characterization of porcine skin in comparison to human skin is not available but will likely improve our understanding of this porcine skin model. Here, we employ Fourier transform infrared (FT-IR) spectroscopic imaging to holistically measure chemical species as well as spatial structure as a function of time to characterize porcine skin as a model for human skin. Porcine skin was found to resemble human skin spectroscopically and differences are elucidated. Cryo-prepared fresh porcine skin samples for spectroscopic imaging were found to be stable over time and small variations are observed. Hence, we extended characterization to the use of this model for dynamic processes. In particular, the capacity and stability of this model in transdermal diffusion is examined. The results indicate that porcine skin is likely to be an attractive tool for studying diffusion dynamics of materials in human skin.     

Polymer bound glutamic acid salicylaldehyde Schiff‐base complex ­catalyst for oxidation of olefins with ­dioxygen

The polymer bound Schiff‐base ligand (PS‐SalGlu) has been prepared from polystyrene bound salicylaldehyde and glutamic acid, and its complex (PS‐SalGlu‐Co) has also been synthesized. The polymer ligand and its complex were characterized by infrared spectroscopy, small area X‐ray photoelectron spectroscopy, and inductively coupled plasma‐atomic emission spectro (ICP‐AFS). In the presence of the complex, cyclohexene can be effectively oxidized by molecular oxygen without reductant. The long‐chain linear aliphatic olefins, such as 1‐octene, 1‐decene, 1‐dodecene and 1‐tetradecene, can be directly oxidized by molecular oxygen catalyzed by PS‐SalGlu‐Co, which affords the 1,2‐epoxy alkane. Copyright © 2001 John Wiley & Sons, Ltd.     

2,4-二氧代-1,3,2-苯并二氮磷杂环己烷与■C=C■及CS_2加成反应的研究

本文研究了2,4-二氧代-1,3,2-苯并二氮磷杂环己烷的磷氢键对β-硝基苯乙烯、丙烯酸酯、丙烯腈及二硫化碳的加成反应,共合成了18个新的加成产物.发现通过选用不同的碱或控制碱的用量.可选择性的进行加成或开环反应.由X衍射证实:在加成产物的结构中,环外P-C键构象因受磷杂环船式构象影响,以邻位交叉式(A)为主.     

Differential protein expression level identification by knockout of 14-3-3τ with siRNA technique and 2DE followed MALDI-TOF-TOF-MS

Cytotrophoblast cell differentiation into syncytiotrophoblast cells is a complex and delicate process, and the mechanism needs a large number of further studies. Knockout of 14-3-3τ expression and some further investigations were performed in the syncytiotrophoblast cell formation with RNA interference (RNAi) technology. The study found that the 14-3-3τ expression level with the formation of syncytiotrophoblast cells increased. Hypoxia inhibited the formation of syncytiotrophoblast cells where 14-3-3τ expression level decreased. RNAi reduced 14-3-3τ expression, and reduced the formation of syncytiotrophoblast cells. So that 14-3-3τ is not only involved in the cell regulation, but also in the formation of syncytiotrophoblast cells. 14-3-3τ is an important regulatory factor which inhibits the formation of hypoxia.     

烟草及烟草制品总挥发酸的测定--连续流动法

采用连续流动方法测定烟草及其制品中的总挥发酸,详细研究了测定条件.结果表明最大吸收波长为350 nm,标准乙酸溶液在0.086～4.0 μg/mL的范围内服从比尔定律,摩尔吸光系数为1.174×104L·mol-1·cm-1,对烟草中挥发酸的检出限为0.012mg/g,相关系数为0.999 5,测定范围为0.12～5.0mg/g.方法具有很好的灵敏度和较高的精密度.     

工业原料铁制备浆态床FT合成用的Fe-Cu-K-Si催化剂的探索

费托合成技术是公认的将煤基合成气转化为液体燃料和化工原料的重要技术途径。虽然固定床费托合成技术从五十年代起已经工业运转，但是浆态床费托合成技术由于其传热性能好，可直接使用第二代气化炉生产的富CO合成气，反应器结构简单，单台反应器生产能力大，开工率高，产品结构合理，     

氨基乙硫醇修饰金电极直接测定芦丁含量的研究

利用分子自组装技术制备氨基乙硫醇修饰金电极,并采用脉冲伏安法直接测定芦丁的含量。以pH7.0的乙醇和磷酸盐混合缓冲溶液作底液,芦丁在氨基乙硫醇修饰金电极上于0.19 V(vs.SCE)处呈现一灵敏的氧化电流峰,峰电流和芦丁的浓度在8.0~2.5×102μmol/L范围内呈良好的线性关系。由于抗坏血酸在氨基乙硫醇修饰金电极上的氧化电位出现显著负移,因此,可避免抗坏血酸对芦丁检测的干扰。本方法可以不经预分离直接检测药物中芦丁含量。     

基于碳水化合物的阳离子聚合物载体在基因释放中的应用

在基因治疗中,基因释放载体是不可缺少的重要组成部分.近几年来聚合物基因释放载体的研究主要旨在开发低毒或无毒的阳离子聚合物用于安全有效的基因释放.作为一类天然化合物,基于碳水化合物的阳离子聚合物载体由于其良好的生物相容性和低毒性被广泛地研究并应用于基因释放.本文阐述了聚合物基因释放的机理,并对近几年来一些典型的含碳水化合物的阳离子聚合物基因释放载体作一综述.