Analysis of Mitochondrial DNA from the Ancient Tombs of Turfan

IntroductionIn general,inferences aboutpopulation historyare drawn from the studies of genetic diversity incontemporary populations.However,the retrievalof ancient DNA from archaeological remains holdsthe promise to add a temporal component to suchstudies. With the invention of polymerase chairreaction(PCR) ,significant amounts of geneticinformation can be recovered from ancient relic.The analysis of DNA from ancient bones can giveimportant implication for anthropology,archaeology and mole…     

[Co(3,3-tri)(men)Cl][ZnCl_4]和[Co(3,3-tri)(cmen)Cl][ZnCl_4]两体系配合物的合成及两经式异构体的晶体结构

分别合成了 [Co(3, 3-tri)(men)Cl][ZnCl4]、[Co(3, 3-tri)(cmen)Cl][ZnCl4] (3, 3-tri = N-(3-胺基丙基)-1, 3-丙二胺,men = N-甲基乙二胺,cmen = 1, 2-二胺基-丙烷) 2体系的部分配合物异构体,用单晶 X-射线衍射分析方法解析了2异构体的晶体结构。其中 [Co(3, 3-tri)(men)Cl][ZnCl4] 体系的一异构体Ⅰ的化学简式为 CoCl(C9H27N5)ZnCl4,晶体属正交晶系,空间群 Pca21,a = 16.788(2),b = 7.964(1),c = 14.416(2) 牛琕 =1927.3(4) ?,Dc = 1.747 g/cm3,Z = 4,F(000) = 1032,Mr = 506.91,R = 0.0352,wR =0.0935;[Co(3, 3-tri)(cmen)Cl]2+ 体系的一异构体Ⅱ的化学简式为 CoCl(C9H27N5)ZnCl4稨2O, 晶体属三斜晶系,空间群 P ,a = 9.511(3), b = 9.972(3),c = 11.694(3) 牛琣 = 68.367(5),b = 85.196(6),?= 86.580(5),V = 1026.9(5)?3,Dc = 1.698 g/cm3,Z = 2,F(000) = 536,Mr = 524.92,R = 0.0494,wR = 0.1180。两异构体中 Co3+ 为六配位,晶胞中对映体比例均为1:1。在配合物异构体Ⅰ和Ⅱ中,三元胺以经式排布,三元胺配体(3, 3-tri)仲胺上的氢相对于Cl分别处于顺位(syn-)和反位(anti-);二元胺配体氮(或邻位碳)取代的胺基氮原子(N*)与三元胺配体中的仲氮原子分别处于对位(trans(N*))和邻位(cis(N*))。     

物质结构教学中虚拟与实体模型的比较研究

本文研究比较虚拟与实体模型在中学化学物质结构教学中作用的目的,就是试图帮助学生建构正确的空间图像思维,尝试鼓励和引导学生建构正确的物质结构思维模式,这对于提高学生的思维品质有很大帮助。     

B2O3/TiO2-ZrO2催化环己酮肟气相Beckmann重排反应研究 Ⅰ.B2O3含量的影响

 制备了不同B2O3含量（0～20％）的B2O3／TiO2－ZrO2固体酸催\r\n化剂，用XRD，FT－IR，N2吸附及NH3－TPD等方法测定了其结构、比表\r\n面积、孔分布和表面酸性．结果表明，当B2O3含量较低（≤5％）时，\r\n催化剂呈无定形态，样品中的B2O3主要以BO4结构存在．当B2O3含量较\r\n高（≥8％）时，催化剂中的TiO2－ZrO2以ZrTiO4晶相存在，分散于Ti\r\nO2－ZrO2表面的B2O3主要以玻璃体形式和BO3结构存在．随着B2O3含量\r\n的增加，催化剂的比表面积减小，孔径增大．300℃下的环己酮肟气相\r\nBeck－mann重排反应结果表明，随着B2O3含量的增加，己内酰胺的选择\r\n性逐渐增大，而己内酰胺的收率在B2O3含量为12％时达到最大值．讨论\r\n了B2O3／TiO2－ZrO2的催化性能与其表面酸性及孔径大小的关系．     

还原气化-原子荧光光谱法快速测定绿色食品基地土壤中的砷与汞

应用还原气化-原子荧光光谱法，使待测元素与基体自动分离、富集，测定绿色食品基地土壤中的AS、HG。经对国家经土壤标准物质进行分析证明，该方法具有快速、准确、灵敏度高等优点，用于绿色食品基地的审评检测，结果令人满意。     

Assessment of intermolecular interactions at three sites of the arylalkyne in phenylacetylene‐containing lithium‐bonded complexes: Ab initio and QTAIM studies

The intermolecular interactions existing at three different sites between phenylacetylene and LiX (X = OH, NH₂, F, Cl, Br, CN, NC) have been investigated by means of second‐order Møller?Plesset perturbation theory (MP2) calculations and quantum theory of “atoms in molecules” (QTAIM) studies. At each site, the lithium‐bonding interactions with electron‐withdrawing groups (? F, ? Cl, ? Br, ? CN, ? NC) were found to be stronger than those with electron‐donating groups (? OH and ? NH₂). Molecular graphs of C₆H₅C?CH···LiF and πC₆H₅C?CH···LiF show the same connectional positions, and the electron densities at the lithium bond critical points (BCPs) of the πC₆H₅C?CH···LiF complexes are distinctly higher than those of the σC₆H₅C?CH···LiF complexes, indicating that the intermolecular interactions in the C₆H₅C?CH···LiX complexes can be mainly attributed to the π‐type interaction. QTAIM studies have shown that these lithium‐bond interactions display the characteristics of “closed‐shell” noncovalent interactions, and the molecular formation density difference indicates that electron transfer plays an important role in the formation of the lithium bond. For each site, linear relationships have been found between the topological properties at the BCP (the electron density ρ_b, its Laplacian ?²ρ_b, and the eigenvalue λ₃ of the Hessian matrix) and the lithium bond length d(Li‐bond). The shorter the lithium bond length d(Li‐bond), the larger ρ_b, and the stronger the π···Li bond. The shorter d(Li‐bond), the larger ?²ρ_b, and the greater the electrostatic character of the π···Li bond. © 2012 Wiley Periodicals, Inc.     

异烟酰肼缩2-乙酰吡啶稀土配合物的制备、晶体结构及抗肿瘤活性

合成并通过元素分析,红外和X-射线单晶衍射表征了3个稀土配合物[Ln(HL)(NO₃)₃(CH₃OH)₂](Ln=La, 1; Ce,2)和[Nd(HL)(NO₃)₃(H₂O)]CH₃OH(3)(HL=2-吡啶酰肼缩2-乙酰吡啶)。在同构配合物1和2中,中心金属离子与提供N₂O配位原子的HL配体,3个双齿配位的硝酸根和2个甲醇分子配位,形成十一配位的单帽五角反棱柱配位构型。在配合物3中,中心金属离子采用十配位的模式与N₂O配位构型的HL配体、3个双齿配位的硝酸根和1个水分子形成双帽四方反棱柱配位构型。2个配合物对人肠癌细胞Lovo,人胃癌细胞BGC823和SGC7901展现出显著的抗肿瘤活性。     

吡咯甲亚胺镍/铜/锌配合物的合成、荧光性质及镍、铜配合物的晶体结构

合成并表征了3个配合物NiL (1),Cu₂L₂ (2)和Zn₂L₂ (3)(H₂L=1,2-双(3,5-二甲基-4-乙氧羰基-吡咯-2-基)苯).单晶衍射结果表明在配合物1中,脱质子配体用4个氮原子与金属NiⅡ配位,中心金属离子为扭曲的平面正方形配位构型.而双核配合物2拥有双螺旋结构,每个配体桥联2个具有平面正方形配位构型的铜中心.推测配合物3和2的结构类似.此外还研究了配体和配合物的荧光性质.     

FT-IR study of the interlamellar water confined in glycolipid nanotube walls

The local hydrogen-bonding environment of water confined in glycolipid nanotubes (LNTs) was investigated by Fourier transform infrared (FT-IR) spectroscopy. Using X-ray diffraction (XRD), we estimated the thickness of an interlamellar water layer, which was confined between the bilayer membranes constructing the walls of the LNTs, to be 1.3 +/- 0.3 nm. FT-IR spectroscopic measurement of the confined water showed an obvious reduction in IR absorption in both the low-energy (around 3000 cm(-1)) and high-energy regions (around 3600 cm(-1)) of the OH stretching band as compared to bulk water. The reduction around 3000 cm(-1) indicated a decrease in the relative proportion of the water molecules with a long-range network structure due to a geometrical restriction. This agrees with the results obtained for other multilamellar systems. On the other hand, the remarkable reduction around 3600 cm(-1), which was not observed in the other systems, indicated the absence of weakly hydrogen-bonded water aggregates due to the effect of sugar headgroups.     

Theoretical study on two types of weak interactions between methylenecyclopropane and XY (X,Y = H,F, Cl,and Br)

We present theoretical evidence that the two types of interactions exist in the complexes formed between methylenecyclopropane (MECP) and XY (X, Y = H, F, Cl, and Br). Two seats of XY interacted with MECP are located: (a) is via the pseudo‐π bonding electron pair associated with a C? C bond of the cyclopropane ring and (b) is via the typical‐π bonding of electron pair of the C?C bond of MECP. These two types of weak interactions are compared based on the calculated geometries, interaction energies, frequency changes, and topological properties of electron density. The integration of electron density over the interatomic surface is found to be a good measure for the strength of weak interaction. Furthermore, the total electron density and separated σ and π electron densities are also computed and discussed in this article. The separated electron density shows σ electron density determined the strength and π electron density influenced the direction of the hydrogen/halogen bond. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011