杂氮三环化合物晶体的X射线衍射研究——Ⅰ.1-硫氰丙基-2,8,9-三氧杂-5-氮杂-1-硅三环[3,3,3,0~(1.5)]十一碳烷的晶体和分子结构

目所指的化合物晶体,属于正交晶系,所属的空间群为Pbca,其晶胞参数为:a=10.575,b=12.215,c=20.786,Z=8。在PW1100四圆衍射仪上收集了1839个独立的衍射数据(I_0>3a(I_0))。晶体结构用直接法解出,经全矩阵和块对角矩阵最小二乘法修正,偏离因子R收敛到0.062。结构测定表明,化合物分子中三个五员环各对应的扭角具有相同的方向,其中两个环的构型基本相同,第三个环略显不同。     

北海航道班轮运输排班模型的构建与求解

首先,以拟开通的大连港至鹿特丹港北海航道班轮航线为研究对象,以油耗和运营成本最小化为优化目标,将官方已有记载的北海航道通过的货船航速数据输入Eureqa软件,得到航行最高速度f(x)与进入北海航道时间t的拟合度最好的函数公式.在此基础上,构建了北海航道班轮运输排班的数学模型;其次,在仿真实例分析中,选用了5000TEU的集装箱船作为计算参数,将捕食搜索算法运用到数学模型求解之中,并且运用MATLAB软件进行求解,在最快航速受限的前提下,得到单艘班轮最佳往返时间和相同型号班轮的最低配置数目以及在服务周期内班轮公司所要付出的最低运营成本;最后,通过比较研究,得出结论是:最快航速的提高,对于降低北海航线班轮运输的运营成本将起较大作用.     

杂氮三环化合物晶体的X射线衍射研究——Ⅱ.1-氯丙基-2,8,9-三氧杂-5-氮杂-1-硅三环[3,3,3,0~(1.5)]十一碳烷-3-酮的晶体与分子结构

题目所指的化合物(NC_6H_(10)O_4Si-CH_2CH_2CH_2Cl)属正交晶系,所属空间群为P2_12_12_1。晶胞参数:a=12.943,b=11.477,c=8.273。Z=4。取1243个可观测独立反射数据,用直接法和Fourier综合解得粗结构,经最小二乘修正,偏离因子R为0.049。三个五员环(Si,O,C,C,N)都有一个较大的扭角,分别为23.7°,41.6°,42.8°。其中带羰基环的最大扭角相对较小(23.7°)。三环最小二乘平面间夹角接近120°,分子中的氯丙基-CH_2CH_2CH_2C1近乎在一个平面上折叠。     

pH和温度诱导双亲水嵌段共聚物聚甲基丙烯酸-b-聚N-(2-甲基丙烯酰氧乙基)吡咯烷酮水溶液的胶束化

基于可逆加成裂解链转移自由基(RAFT)聚合法开发了一系列新型双亲水嵌段共聚物——聚甲基丙烯酸-b-聚N-(2-甲基丙烯酰氧乙基)吡咯烷酮(PMAA-b-PNMP),并利用凝胶渗透色谱法(GPC)和¹H NMR对其结构进行了表征。光散射和冷冻电镜的结果表明,此类双亲水嵌段共聚物的水溶液具有pH和温度诱导胶束化的现象,而且PNMP的聚合度对胶束化的pH和温度影响都非常大。一般而言,PNMP的聚合度越大,胶束化的pH值越小,胶束化的温度则越高。pD相关的¹H NMR结果表明,PNMP与PMAA片段和水分子之间氢键的削弱以及PNMP与PMAA链之间相互作用的增强是pH诱导PMAA-b-PNMP胶束形成的主要原因,而PNMP片段与水分子之间氢键的削弱则是温度诱导PMAA-b-PNMP胶束形成的主要原因。此外,我们发现在PMAA-b-PNMP体系中制备的纳米金颗粒的大小可通过溶液pH进行可控调节。总体而言,pH值越高,金纳米颗粒的粒径越小。     

胰岛素分子与其受体结合的可能机制

以最小二乘叠合技术和图象显示技术对DPI、二锌胰岛素及其他一些衍生物结构进行了深入的比较和分析,确认与受体分子的结合相互作用是发生在胰岛素分子的一个两性表面上,其中部是由许多疏水残基构成的面积约150~2的疏水表面,而一些极性基团在其周围构成亲水带区。疏水表面通常被运动性很大的B链羧端肽段所覆盖,不受极性溶剂分子的干扰。两性表面在方位上与分子在二体中的缔合面构成约20°的夹角。Al-L-Trp胰岛素及Al-D-Trp胰岛素结构详细的比较结果,既很好地解释了两者在生物活性上的显著差异,又进一步确认了我们所提出的胰岛素分子与其受体结合的作用模型。     

STUDIES ON ORGANOMETALLIC COMPOUNDS OF TITANIUM,ZIRCONIUM AND HAFNIUM——THE CRYSTAL AND MOLECULAR STRUCTURES OF OXO-BRIDGED TETRAKIS(CYCLOPENTADIENYL)BIS (o.TOLYL)AND TETRAKIS(METYLCYCLOPEN-TADIENYL) BIS(p-TOLYL)BINUCLEATED ZIRCONIUM COMPOUNDS

This paper reports the crystal and molecular structures of tetrakis (cyclopentadienyl) bis(o-tolyl)-μ-oxo-dizirconium [dimer (Ⅰ)] and tetrakis (methylcyclopentadienyl) bis (p-tolyl)-μ-oxo-dizirconium [dimer (II)]. Both of them belong to monoclinic system and possess the same spacegroup C_2~5h- 2_1/a. The cell dimer (Ⅰ) containing four molecules is defined by a=19.122A,b=16.319A, c = 9.296A, β= 92°1′; the cell dimer (Ⅱ) containing two molecules is defined bya = 20.076A, b = 8.205A, c = 10.016A, β= 104°41′. The important difference of molecular configurations between the two dimers lies in thatthe dimer (Ⅰ) has no symmetry center and its Zn-O-Zr oxo-bridge presents a slightly bentconfiguration while the dimer (Ⅱ) takes the oxgen atom as a symmetry center and its oxo-bridge present linear linkage. In accordance with the above-mentioned molecular configuration, steric effect and elec-tronic structure have been further discussed.     

THE POSSIBLE MECHANISM OF BINDING INTERACTION OF INSULIN MOLECULE WITH ITS RECEPTOR

Detailed structural comparisons and investigation of DPI, 2Zn insulin and some other derivatives of insulin were performed by the least-squares superimposition technique and the graphics technique. It is pointed out in this paper that the binding interaction with the receptor molecule should take place mainly on an amphipathic surface of the insulin molecule. In the middle, there is a hydrophobic surface with an area of about 150 consisting of many hydrophobic residues; while the polar or charged groups distributing around the hydro. phobic surface construct a hydrophilic zone. The hydrophobic surface is usually covered by the extended B-chain C-terminal peptides with great mobility and protected from the solvent molecules. The angle between the amphipathic surface and the surface of dimerization is about 20 degrees. The results from the detailed structural comparison between A1-(L-Trp) insulin and A1-(D-Trp) insulin have provided a very good explanation to their great difference in biological activity,     

REFINEMENT OF THE CRYSTAL STRUCTURE OF INSULIN AT 1.2 RESOLUTION

The crystal structure of 2 Zn porcine insulin has been refined at 1.2 resolution. The reciprocal space refinement was restrained by the incorporation of extensive chemical observations into the least squares equations. In addition to the non-hydrogen atoms, hydrogen atoms of protein, water molecules and the bulk solvent have been determined and refined. After two cycles of anisotropic refinement of non-hydrogen atoms of insulin, the final agreement factor was 0.128 for 20,005 reflexions (F_o>1σ(F_o)) in a spacing 1.2 and the root mean squares deviation from ideal covalent bond lengths was 0.021. On the electron density maps, the appearances of weight and shape of non-hydrogen atoms were very clear and reasonable. The anisotropic appearances of sulphur atoms could be seen clearly. After anisotropic refinement, the situation fit to the electron density was improved distinctly.     

溴代还原青蒿晶体结构研究

溴代还原青蒿(C₁₇H₂₇O₅Br),晶体属单斜晶系,空间群P2₁。晶胞中含两个分子。晶胞参数:α=10.34?,b=9.160?,c=9.353?;β=90°,z=2。衍射数据由Philips PW-1100四圆衍射仪测定。用Patterson法求解。晶胞中两个重原子溴呈中心对称配置,故生双解。分别用立体化学知识判别和用直接法均得到同一套单解。分子的绝对构型是用反常散射法确定的。用全矩阵最小二乘法对原子坐标参数、比例 关键词：     

1.2分辨率胰岛素晶体结构的修正

在1.2分辨率修正了三方二锌猪胰岛素的晶体结构。采用将广泛的立体化学观测量并入最小二乘方程加以制约的倒易空间修正方法。在对蛋白质非氢原子和氢原子、水及溶剂相分别进行各向同性温度因子的修正和校正之后,对胰岛素二体的全部非氢原子进行了两轮各向异性温度因子的修正.对于1.2范围内的20005个大于1σ的独立反射的最终R因子是0.128,与理想共价键长的均方根偏差是0.021。在最终的电子密度图上有清晰的原子水平的密度表现,硫原子的电子密度的各向异性分布表现明显。经各向异性温度因子修正后,电子密度的拟合情况有明显改善。