深海耐盐杆菌来源酯酶PE8的表达纯化、结晶和晶体X-ray衍射研究（英文）

从深海耐盐杆菌Pelagibacterium halotolerans B2T中分离鉴定的酯酶PE8隶属于酯酶第六家族.因具有耐盐、较高的热稳定性、高手性选择性,PE8是工业上高效生产手性药物前体(R)-3-(4-氟苯基)戊二酸单甲酯((R)-3-MFG)很有开发潜力的催化剂,但其分子催化机理并不清楚.PE8在大肠杆菌中体外表达,并通过镍柱亲和层析,以及凝胶过滤层析纯化,最终通过悬滴结晶方法获得了PE8蛋白晶体.晶体经过X-ray衍射分析获得1.66的分辨率,属于空间群P21,晶胞参数为a=41.772,b=73.398,c=66.403,β=102.37°.一个异构单元包含2个蛋白分子,溶剂(水)含量为35%.     

Fe~(Ⅲ)(acac)Py_2Cl_2的合成和晶体结构

三氯化铁、乙酰丙酮(acacH)和吡啶(Py)在乙腈中反应得到标题化合物晶体。X-射线单晶衍射的研究表明,晶体属单斜晶系,空间群是P2_1/c,晶胞参数α=13.196(6)A,b=9.146(4)A,c=15.305(8)A,β=110.10(4)°,晶胞体积V=1734.6A~3,经验式量FW=384.1,分子数Z=4,吸收系数μ=15.85cm~(-1),计算的密度D_c=1.47gcm~(-3),最终偏差因子R=0.044,R_w=0.056。络合物的分子构型为变形八面体,两个氯原子处于顺式位置而两个吡啶分子处于反式位置。     

柔性二芳醛通过弱相互作用键构筑的超分子结构

以1,4-二溴丁烷和对羟基苯甲醛为原料,合成了1,4-二对甲酰苯氧基丁烷(化合物1).单晶X-射线衍射分析表明该化合物的晶体属于单斜晶系,空间群为P21/c,晶胞参数α=7.983 0(16)(A),b=6.677 0(13)(A),c=14.244(3)(A),α=90.00°,β=96.34(3)°,γ=90.00°,V=865.9(3)(A)3,Z=4,Mr=298.32,Dc=1.313 g/cm3,F(000)=316.晶体结构用直接法解出,经全矩阵最小二乘法对原子参数进行修正,最终的偏离因子为R1=0.045 6,ωR2=0.112 4[I>2σ(I)].该晶体中柔性有机分子通过分子间C-H…0弱氢键和π-π堆积形成了多种超分子结构.     

3-羧酸香豆素的合成,表征和晶体结构

应用Meldrum酸和2-甲氧基苯甲醛制备了3-羧酸香豆素(C10H6O4, Mr=190.15),并用元素分析﹑IR和1H NMR手段进行了表征. 化合物的晶体X-射线衍射分析表明,晶体为单斜晶系,空间群为P21/n, a=11.344(3), b=5.517(1), c=13.820(4)(A), β=106.31(1)°, V=830.1(4)(A)3, Z=4, Dc=1.521 g/cm3, F(000)=392 和μ(MoKα)=0.763 mm-1(λ=0.71073(A)). I＞2σ(I)的衍射数为1 466,最后结构精修因子为R1=0.037 8和wR2=0.1036. 晶体结构分析表明,在分子中存在有一个共平面和一个分子内H键.     

2-羧甲硫基-4，6-二甲基嘧啶的合成、表征和晶体结构

合成了化合物2-羧甲硫基-4,6-二甲基嘧啶一水合物,C6H12N2O3S,并用元素分析、IR和1HNMR进行了相关的表征.此化合物的晶体应用X一射线单晶衍射法进行了结构分析.晶体为单斜晶系,空间群P21/n,a=7.654 3(10),b=10.744 1(13),c=13.267 9(17)(A),β=100.797(3)*.Z=4,V=1 071.8(2)(A)3,Dc=1.340 g/cm3,F(000)=456和,μ(MoKa)=0.763(λ=0.710 73 (A)).对于1 451个观察到的衍射点(I>2σ(I)),结构可以精修到R1=0.0591和wR2=0.154 3.所测得的晶体结构显示,在水和3个2-羧甲硫基-4,6-二甲基嘧啶分子之间,存在有3个分子问氢键.在分子中,S原子与2个C原子形成S-C键,其键长分别为1.765(3)和1.790(3)(A).     

4-甲基苯甲酸乙酯中的C-H…O氢键自组装

4-甲基苯甲酸乙酯由4-甲基苯甲酸在热的乙醇溶液中酯化获得,在室温下缓慢蒸发溶剂得到晶体。用元素分析、IR、X射线单晶衍射分析进行了结构表征。结构分析表明,晶体属单斜晶系,P21/c空间群,a=1.179 8(1)nm,b=1.3209(1)nm,c=1.160 0(1)nm,β=107.706(2)°,V=1.721 9(3)nm3,Z=8,ρ=1.267 g/cm3,C10H12O2,Mr=164.20,F(000)=704,μ(MoKα)=0.87 nm-1,R=0.084 1和wR=0.2789。总衍射点8 557个,独立衍射点3 027个,可观察点1 902个,满足I>2σ(I)。通过甲基与相邻分子的羰基之间的C-H…O氢键将4-甲基苯甲酸乙酯分子沿b轴方向组装成一维Z字超分子链。     

混配配合物[Cu(1,10-phen)(CH2(COO)2)(H2O)]2·3H2O的合成和晶体结构

在碱式碳酸铜与丙二酸水溶液反应后的滤液中加入1,10-(口菲)啰啉的乙醇溶液,放置获得一种蓝色块状的晶体.X-ray衍射显示为三斜P-1群,α=11.560(2),b=11.750(2),c=12.510(3)A,α=92.13(3)°,β=105.50(3)°,γ=109.30(3)°,v=1530.6(5)A3,z=2,Mr=781.66,F(000)=800,Dc=1.696g/cm3,μ(M0Kα)=1.467mm-1,R=0.0392.二聚体[Cu(1,10-phen)(CH2(COO)2)(H2O)]2是通过分子间的氢键形成的.     

三聚氰胺晶体中的氢键作用

采用X-射线衍射方法测定三聚氰胺的晶体结构,测定结果表明,该晶体属单斜晶系,P2(1)/c空间群,晶胞参数为:a=7.267(3) (A),b=7.464(3) (A),c=10.567(3) (A),α=90.0°,β=112.26(2)°,γ=90.0.,y=530.4(3) (A)3,Z=4,μ=0.118 mm-1,Dc=1.579 g/cm3,R=0.0618,ωR2=0.1564.在三聚氰胺晶体中存在着N-H…N分子间氢键,该氢键作用使三聚氰胺晶体结构更加稳定.     

8-［4-吡啶］-1,3,5,7-四甲基-2,6-二溴氟硼二吡咯甲川的晶体生长、结构表征和光谱性质

利用溶液晶体生长法,将8-［4-吡啶］-1,3,5,7-四甲基-2,6-二溴氟硼二吡咯甲川(BDP-Br₂)溶于乙醇-水混合溶剂中,自然挥发,可获得BDP-Br₂单晶.X-射线晶体学分析表明,BDP-Br₂晶体属单斜晶系P2₁/c空间群,分子式为C₁₈H₁₆BF₂N₃Br₂,M_r=482.97.其晶体学参数如下:a=1.500 7(1)nm,b=1.129 5(1)nm,c=2.225 9(2)nm,β=90.949(8)°,Z=8,ρ_c=1.701 g·cm^-3,R=0.073,R_w=0.164,拟合优度(GOF)=1.010.在BDP-Br₂晶体结构中,每个BDP-Br₂染料分子通过分子间C-H…F氢键和C-H…π超分子作用,组成Z形分子链反向交替堆积的三维分子阵列结构.固相和溶液相的BDP-Br₂染料分子可分别于550和561 nm处观察到光致发光现象.     

锌配合物ZnL(PMA)0.5·1.5H2O的合成、晶体结构

通过水热合成法合成了配位聚合物ZnL(PMA)o.5·1.5H2O(1),其中H4 PMA为均四苯甲酸,L为4,4′,4”-(1H-咪唑-2,4,5-三基)三吡啶.用单晶X-ray衍射法测定了它的晶体结构,该晶体属单斜晶系,空间群P2(1)/c,a=10.465(9),b=9.818(4),c=20.558(3)(A),p=92.85(4)°,V=2109.92 (A)3,C23H17N5O5.5Zn,Mr=516.82,Z=4,Dc=1.846g/cm3,F(000)=1032.0,R=0.0491,wR=0.1113(Ⅰ＞2ó(Ⅰ)),2 471个可观测衍射点.该分子为配位聚合物,锌原子位于由2个L配体氮原子和2个均四苯甲酸羧酸氧原子构成的四面体中.结构分析表明,这种配位聚合物通过分子间氢键形成了一种新型的三维网络互穿结构.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with