Mitochondrial Cytochrome b Sequence Variations and Population Structure of Siberian Chipmunk (Tamias sibiricus) in Northeastern Asia and Population Substructure in South Korea

Twenty-five chipmunk species occur in the world, of which only the Siberian chipmunk, Tamias sibiricus, inhabits Asia. To investigate mitochondrial cytochrome b sequence variations and population structure of the Siberian chipmunk in northeastern Asia, we

有机结构解析专家系统CAMOS的研制

本文系统地介绍了有机结构解析专家系统CAMOS（Computer Automatted Manipulation of Organic Structures)的研制，建立结构解析专家系统的目的是应用计算机人工智能技术，充分应用化学家的知识和经验，模拟结构解析的思维过程，辅助各种现代结构分析手段，达到用计算机自动解析结构的目的。本文分七个部分介绍CAMOS系统。第一部分介绍系统整体设计和组织以及运行环境。第二部分介绍亚结构的生成和描述。系统从未知物的分子式出发，采用迭代法生成所有符合元素组成的亚结构。生成过程分为两级，先由分子式生成元素组成亚结构（ECSS)，再由EGSS生成键性亚结构（BASS)。然后描述BASS的元素性质（EA)和键性质（BA)。根据集合论，将BASS看成一个集合，则EA和BA为两个子集，通过对EA和BA进行逻辑运算，可以判断任意两个BASS之间是否能成键，生成的亚结构可以用已知的化的亚结构集合。第三部分介绍分子整体结构的生成。作者根据图论，提出了分子结构树生成算法，即用经过挑选的亚结构在一定的约束条件下来构造分子结构树，一棵完整的结构树即为一个候选结构，它必须符合分子式和联接性。算法可迭代生成所有的结构树。生成的候选结构用亚结构联接矩阵SSCM表示。为了减少组合过程中所占存储量，缩短生成时间，本系统中采用了SSGM变换技术，即，将生成的一个候选结构的SSGM进行穷举变换，可得到所有候选结构的SSGM，这对于含多个亚结构的分子的结构生成很有效。第四部分介绍作者提出的一种新的亚结构编码SSTNC（Substructure Tree Numerial Gode)。这种编码可用于亚结构参与结构变换的过程。在GAMOS中，SSTNC用于生成候选分子结构的二维联接表。SSTNC具有很好的唯一性，可减少重复结构的生成。第五部分介绍候选结构的验证。有两个策略，一是模拟候选结构的碳－13核磁共振谱，与未知物的实验谱比较，比较的方法有谱峰个数比较和化学位移比较，去掉与实验谱不符合的候选结构。二是用相似度经验公式计算模拟谱与实验谱的相似性，按相似度排队。第六部分介绍结构的显示。CAMOS系统移植了R.E.Carhart报导的结构显示程序，设计了接口，生成的二维联接表可直接用于结构的显示。最后以一个实例演示CAMOS的解析过程。CAMOS系统目前只是个模型系统，可在小型机或微机上运行。程序用FORTRAN－77语言编写。系统的功能将随着库中内容的增加和推理规则的严格而加强。

Segmented All-Platinum Nanowires with Controlled Morphology through Manipulation of the Local Electrolyte Distribution in Fluidic Nanochannels during Electrodeposition

Synthesis of segmented all-Pt nanowires is achieved by a template-assisted method. The combination of a suitably chosen electrolyte/template system with pulse-reverse electrodeposition allows the formation of well-defined segments linked to nanowires. Manipulation of the morphology is obtained by controlling the electrokinetie effects on the local electrolyte distribution inside the nanochannels during the nanowire growth process, allowing a deviation from the continuously cylindrical geometry given by the nanoporous template. The length of the segments can be adjusted as a function of the cathodic pulse duration. Applying constant pulses leads to segments with homogeneous shape and dimensions along most of the total wire length. X-ray diffraction demonstrates that the preferred crystallite orientation of the polycrystalline wires varies with the average segment length. The results are explained considering transitions in texture formation with increasing thickness of the electrodeposit. A mechanism of segment formation is proposed based on structural characterizations. Nanowires with controlled segmented morphology are of great technological importance, because of the possibility to precisely control their substructure as a means of tuning their electrical, thermal, and optical properties. The concept we present in this work for electrodeposited platinum and track-etched polycarbonate membranes can be applied to other selected materials as well as templates and constitutes a general method to controlled nanostructuring and synthesis of shape controlled nanostructures.

Separation of drug enantiomers by capillary electrophoresis in the presence of neutral cyclodextrins

This is a selected review, highlighting our results obtained in an extended screening program ("The German-Chinese Drug Screening Program"), with a focus on a set of original data obtained with heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin(TM-beta-CD) as the chiral solvating agent (CSA). The enantioseparation of 86 drugs by capillary zone electrophoresis in the presence of this CSA was successful for 47 drugs. The migration separation factors (alpha(m)) and the migration retardation factors (R-m) were compared with those found for native beta-cyclodextrin (beta-CD). The patterns thus obtained were also compared with those observed for hexakis(2,3,6-tri-O-methyl)-alpha-CD (TM-alpha-CD) and octakis(2,3,6-tri-O-methyl)-gamma-CD (TM-gamma-CD), respectively. From the statistical data, it can be concluded that there is a remarkable influence of the analyte structure on the electrophoretic data. A substructure 4H was found in the analyte structure that has a significant influence on the analytes' behaviour. Thus, analytes bearing the substructure 4H do not only have a strong affinity to the CDs but also a high rate of success of chiral separation in all systems reviewed. In light of this, the different ring sizes of native cyclodextrins (alpha-, beta- and gamma-CD) readily explain their behaviour towards a limited test set of chiral drugs. Sterical considerations point to the significance of side-on-binding versus inclusion in the cavity of the host. In addition to the findings from the screening program, numerous references to the Literature are given. (C) 2000 Elsevier Science B.V. All rights reserved.

EXPERT-SYSTEM FOR ELUCIDATION OF STRUCTURES OF ORGANIC-COMPOUNDS

An expert system for the elucidation of the structures of organic compounds-ESESOC-II has been designed. It is composed of three parts: spectroscopic data analysis, structure generator, and evaluation of the candidate structures. The heart of ESESOC is the structure generator, as an integral part, which accepts the specific types of information, e.g. molecular formulae, substructure constraints, and produces an exhaustive and irredundant list of candidate structures. The scheme for the structural generation is given, in which the depth-first search strategy is used to fill the bonding adjacency matrix (BAM) and a new method is introduced to remove the duplicates.