山梨醇改性聚乙烯醇体系的氢键作用及对水状态的影响

采用二维相关红外光谱研究了水渗透进入聚乙烯醇(PVA)及其改性基体过程中, 体系的氢键作用及对水状态的影响; 通过差示扫描量热分析(DSC)研究了改性剂山梨醇(S)对改性PVA中水状态的影响. 实验结果表明, S能通过其羟基与水形成较强氢键, 从而显著改变体系中水的状态及其蒸发行为, 使体系自由水含量逐渐减少, 水的蒸发峰温度升高.     

肝癌及癌旁组织中微量元素含量研究

为探讨肝癌患者的癌、癌旁和正常组织中微量元素含量的变化 ,收集了 3 0例肝癌患者的癌、癌旁及正常组织 ,应用等离子体发射光谱仪测定了Se、Zn、Cu、Fe、Mg、Mn、Mo的含量。结果表明 ,肝癌患者的正常、癌旁、癌组织Se、Zn、Mg、Mo的含量和Se/Cu、Zn/Cu、Fe/Cu、Mg/Cu、Mo/Cu的比值逐渐降低 (P <0 0 1～ 0 0 5 ) ,但Cu、Mn的含量则相反逐渐升高 ,Fe的含量和Mn/Cu的比值无显著差异 (P >0 0 5 )。本研究提示 ,微量元素含量的变化与肝癌发生、发展有相关性 ,对癌变过程的研究和临床治疗的指导具有重要意义     

聚乳酸-聚乙二醇单甲醚共混体系的调制DSC分析

采用调制差示扫描量热法(MDSC)研究了聚乳酸(PLA)与聚乙二醇单甲醚(MPEG)共混体系的热性能。研究结果表明,MDSC可有效分辨PLA重结晶和熔融的重叠效应,在测试条件下,PLA的α’-α晶型转变与α晶体的熔融几乎同时进行。随着升温速率的加快和调制周期的延长,当增塑剂的质量分数为15%时,PLA-MPEG共混物分割在不可逆曲线的重结晶焓逐渐升高(最高约28J/g),熔融焓逐渐降低(最低约为3.3J/g);分割在可逆曲线的熔融峰逐渐由多重峰变为单峰,且焓变值逐渐升高(最高约66.1J/g),相应的可逆曲线熔融分割比例达到了95.2%。通过提高升温速率和延长调制周期,可使大部分熔融分割在可逆曲线上,但过快的升温速率和过长的调制周期会导致PLA相转变时的周期数过少,DSC调制功能的分辨率下降,设置测试条件时需综合考虑。     

血镁水平与糖尿病肾病

为探讨糖尿病肾病 (DN)患者血镁水平 ,以 1 5 9例 2型糖尿病 (T2DM)患者为研究对象 ,用xylidylblue比色法测定了其正常白蛋白尿期、微量白蛋白尿期 (早期DN)、临床DN及晚期DN血镁水平 ,与 2 0例正常对照组相比较 ;同时将 1 1 0例DN患者分为肾功能不全代偿组、失代偿组和肾功能衰竭组 ,将其血镁水平与 1 0 2例慢性肾小球肾炎 (CGN)患者相比较 ,组间比较采用t检验 ;对 79例T2DM正常白蛋白尿期及微量白蛋白尿期患者尿白蛋白排泄率 (UAER)与血镁水平进行了等级相关分析。结果表明 ,T2DM正常白蛋白尿期、早期DN及临床DN血镁水平降低 ,晚期DN血镁水平升高 ,各组与正常对照组相比存在显著性差异 (P <0 0 5或P <0 0 1 ) ;T2DMDN及CGN肾功能不全代偿期、失代偿期及肾功能衰竭期血镁水平渐升高 ,且肾功能处于同一期的DN和CGN相比 ,前者血镁水平均较后者显著降低 (P <0 0 1或P <0 0 5 ) ;T2DM正常白蛋白尿期和微量白蛋白尿期血镁水平与UAER呈负相关 (r=0 5 47,P <0 0 1 )。提示T2DM患者肾功能正常时存在低镁倾向 ,但晚期DN血镁水平升高 ;随着肾功能不全进展 ,DN和CGN患者血镁水平升高 ,但前者血镁水平仍较后者低 ,镁代谢紊乱与DM及其并发症的相互关系有待进一步研究 ;血镁水平测定可否作为DN的早期诊断指标亦     

有机半导体

一、前言根据物质导电的能力,可以把它們分为三类:即导体(金属)、半导体和絕缘体。三类物质的能带分布如图1所示。从图1可以看出金属与絕緣体和半导体不同,在价电子带(滿带)与导带之間沒有禁带(△E=0),因此价电子都可以参与电流的传导作用。半导体的能谱中則有禁带存在,因此在正常状态下处于滿带中的价电子不能参与电流的传导作用。但是当受到热激活或光激活作用时,滿带中的电子可以被激发至导带,因而具有一定的电导。绝缘体在这方面与半导体并无原则区别,只是禁带宽度較大,换句话说,也就是把电子激发至导带时所需的激活能較大。此外,金属的电导随温度的升高而降低,而半导体的电导則随溫度的升     

分子动力学模拟研究质子化态在HIV-1 Protease-Indinavir复合物中的作用

I 型人体免疫缺陷病毒(HIV-1)蛋白酶中Asp25/Asp25'的质子化对于理论研究HIV-1 蛋白酶和抑制剂的作用机制
以及氨基酸变异对抗药性的影响有重要意义. 分别对Protease-Indinavir (PR-IDV)复合物的六种可能的质子化态进行了
5 ns 的分子动力学模拟, 分析了不同状态对动力学特征和结构的影响, 用molecular mechanics/Possion-Boltzman surface
area (MM-PBSA)方法计算了PR 和IDV 在各种状态下的结合自由能. 计算结果说明A 链Asp25 的OD2 的质子化是最
为可能的状态. 对PR-IDV 复合物中起到媒介作用的水分子与PR-IDV 复合物形成的氢键进行了分析, 分析结果说明不
同的质子化态对水分子在PR-IDV 复合物中所起的媒介作用没有影响, 这一结果与我们先前对PR-BEA369 复合物的研
究不同. 我们的研究结果为更高效的PR 抑制剂的设计以及PR 氨基酸变异对药物抗药性的研究提供了理论上的指导.     

动力学因素对热诱导相分离法制备亲水性乙烯-丙烯酸共聚物微孔膜结构的影响

选择 3种不同丙烯酸含量的乙烯 丙烯酸共聚物 (EAA)为原材料 ,二苯醚 (DPE)为稀释剂 ,研究了淬冷温度、粗化时间等影响液滴生长的动力学因素对热诱导相分离法 (TIPS)制备EAA DPE亲水性高分子微孔膜结构的影响 .淬冷温度的高低决定了EAA DPE体系是发生液 液相分离还是固 液相分离 ,而产生相分离的机理不同将影响稀释剂液滴的生长 ,最终影响微孔膜的孔径 .实验结果表明 ,在相同粗化时间的条件下 ,随着EAA1 41 0 DPE、EAA3 0 0 2 DPE、EAA3 0 0 3 DPE三体系冷却温度的逐渐升高 ,孔径逐渐变大 .在结晶温度以下 ( 0℃、3 0℃、60℃ )粗化时间相同时 ,温度对微孔膜的孔径影响较小 ,例如 0℃和 3 0℃的恒温条件粗化 1 0min,微孔膜的孔径在 1～ 3 μm之间 ;在 60℃的恒温条件粗化 1 0min ,微孔膜的孔径在 3～ 5 μm之间 .而在 90℃的恒温条件粗化相同的时间 ,由于体系始终处于结晶温度线以上 ,体系始终处在液 液相分离区域 ,最终得到微孔膜的孔径达到了 6～8μm .在结晶温度以下 ( 3 0℃ )进行恒温粗化 ,由于体系的过冷程度很大 ,液滴相的粗化过程被抑制住 ,所以粗化时间对微孔膜的孔径影响不大 ;而在结晶温度以上 ( 90℃ )进行恒温粗化时 ,则是随着粗化时间的延长 ,微孔膜的孔径逐渐变大     

Ni/AlPO4-11分子筛的TEM及FMR研究

新型磷酸铝分子筛负载镍后改进了表面酸性,使裂化活性大为升高。用透射电子显微镜(TEM)及电子顺磁共振技术(EPR)进一步证实了Ni(0)是裂化反应的活性中心。由EPR测得各种还原温度下Ni/AlPO_4-11的Ni(0)的铁磁共振谱(FMR),各谱线的g因子均为2.2,但Ni(0)铁磁共振谱的相对强度却随还原温度的升高而增强。从透射显微图得知随还原温度升高Ni(0)的金属晶体逐渐增大,从分散度较好的小颗粒递变为分散度较差的大颗粒,致使活性递减。从FMR谱图可以看出,不同还原温度下所得的线宽随镍晶粒的增大而降低。     

微纳电极阵列检测丘脑底核电刺激引起的纹状体神经元活动变化

丘脑底核(STN)深部脑刺激(DBS)已成为帕金森病的重要外科治疗手段,然而其确切的作用机理尚不明确.本研究采用微机电系统(MEMS)技术制备了一种16通道植入式微电极阵列(MEA),在MEA表面修饰了铂黑-还原氧化石墨烯-Nafion膜(Pt/RGO/Nafion)纳米材料,用于同步检测麻醉大鼠脑内纹状体神经元在STN电刺激前后多巴胺(DA)含量和动作电位(Spike)发放变化.STN-DBS结果表明,电刺激20 s后,DA含量开始升高,最高达1.72 μmol/L,较高浓度状态保持约50 s后回落至正常水平.与此同时, 检测到在DA上升阶段中间神经元Spike发放活动增强,在保持高于DA正常浓度水平阶段,中等多棘神经元(MSNs)放电频率增加.本研究制备的微电极阵列传感器能够实现脑内多巴胺和电生理的原位实时检测,有望成为神经信息检测的有力工具.     

周期扰动位相对化学振荡的调制效应

由Rossler反应系统的理论模型出发,构造一种具有外部周期扰动的新动力学系统,并采用逆算符法和数值分析法研究该系统的振荡态在周期扰动调制下的动力学行为.结果表明,在周期扰动的调制下,系统的状态由单周期振荡态(1p)变为周期2(2p)、周期4(4p)等多周期振荡态以及混沌态.扰动位相是系统呈现上述多种演化模式的控制参数,在扰动位相不同的数值区间,系统呈现的演化模式不同,而且扰动位相数值的微小改变,还影响每种演化模式的内部结构.     

Thermal Analysis of Ba(II)–Sr(II) Cyclo-Tetraphosphates(V)

The synthesis of new inorganic pigments has been investigated with the goal of preparing heat stable and anticorrosive pigments. The synthesis is based on a thermal procedure making use of the reversible transformation of cyclo-tetraphosphates(V) to higher linear phosphates(V). New binary condensed phosphates were synthesized based on the results of thermal analysis. These compounds represent new environmentally-friendly special pigments. This revised version was published online in August 2006 with corrections to the Cover Date.     

Electrochemical Determination of Carbofuran in Tomatoes by a Concanavalin A (Con A) Polydopamine (PDA)-Reduced Graphene Oxide (RGO)-Gold Nanoparticle (GNP) Glassy Carbon Electrode (GCE) with Immobilized Acetylcholinesterase (AChE)

A new biosensor method was developed to determine residual carbofuran in tomatoes in a rapid and convenient fashion based on immobilizing acetylcholinesterase (AChE) on an electrode modified by concanavalin A (Con A)/polydopamine (PDA)-reduced graphene oxide (RGO)-gold nanoparticle (GNP) nanocomposites. The specific binding between Con A and AChE was investigated by the Ellman method and cyclic voltammetry (CV). The synthesis of nanocomposites was monitored by ultraviolet-visible absorption spectroscopy, scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The results showed that, due to the specific binding and good electrical conductivity, the biosensor had 2.2 times higher bioactivity, leading to high sensitivity with a low Michaelis constant of 0.10?mM. Parameters that affect the response of the biosensor, such as the pH, enzyme loading, ionic concentration, and inhibition time, were optimized. When used for the detection of carbofuran, this biosensor showed a wide range of applicability from 5?µg/kg to 40?µg/kg with a detection limit of 0.012?µg/kg. In addition, the biosensor demonstrated good recovery values of 101% and 90% for 10?µg/kg and 100?µg/kg of the analyte, good stability, high repeatability, and a rapid detection time of 20?min for carbofuran in tomatoes, which provides significant advantages for future analysis.     

Extraction chromatographic study of aluminium(III) and mutual separation of aluminium(III), gallium(III), indium(III) and thallium(III) with N-n-octylaniline

A selective method has been developed for extraction chromatographic studies of aluminium(III) and its separation from several metal ions with a chromatographic column containing N-n-octylaniline (liquid anion exchanger) coated on silanized silica gel as a stationary phase. The aluminium(III) was quantitatively extracted with the 0.065 mol/L N-n-octylaninine from 0.013 to 0.05 mol/L sodium succinate at a flow rate of 1.0 mL/min. The extracted metal ion has been recovered by eluting with 25.0 mL of 0.05 mol/L hydrochloric acid and estimated spectrophotometrically with aurintricarboxylic acid. The effects of the acid concentration, the reagent concentration, the flow rate and the eluting agents have been investigated. The log-log plots of distribution coefficient (KdAl(III)) versus N-n-octylaniline concentrationin 0.005 and 0.007 mol/L sodium succinate gave theslopes 0.5 and 0.7 respectively and showed theprobable composition of theextracted species was 1:1 (metal to amine ratio) and the nature of extracted species is [RR''NH2+ Al succinate2-] org. .The extraction of aluminium(III) was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. Aluminium(III) has been separated from multicomponent mixtures, pharmaceutical samples and synthetic mixtures corresponding to alloys. A scheme for mutual separation of aluminium(III), indium(III), gallium(III) and thallium(III) has been developed by using suitable masking agents. The method is fast, accurate and precise.     

Rhodium(III), palladium(II) and platinum(II) complexes of Bis(o-aminobenzenesulfonyl)ethylenediamine

New complexes of the formulae K₃[RhL ₃]·2 H₂O, [PdL]·H₂O and [M(LH₂)Cl₂] [whereM = Pd, Pt andLH₂ = bis(o-aminobenzenesulfonyl)ethylenediamine] have been prepared and characterized by conductivity measurements, thermogravimetric analysis, X-ray powder patterns and IR, Ligand Field and¹H-NMR spectroscopy.

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Rhodium(III), Palladium(II)- und Platin(II)-Komplexe mit Bis(o-aminobenzolosulfonyl)ethylendiamin (Kurze Mitteilung)

Zusammenfassung Neue Komplexe der allgemeinen Formeln K₃[RhL ₃]·2H₂O, [PdL]·H₂O und [M(LH₂)Cl₂] mitM = Pd, Pt undLH₂ = Bis(o-aminobenzolosulfonyl)ethylendiamin wurden dargestellt und mit Konduktionsmessungen, thermogravimetrischen Analysen, Röntgenstrukturanalysen, IR, Ligandfeld- und¹H-NMR-Spektroskopie charakterisiert.

     

手性二噁唑啉吡啶铁和镍配合物的制备与表征

Tridentate bis(oxazolinylpyridine)(1) reacted with nickel chloride or ferrous chloride in anhydrous ethanol to form bis(oxazolinylpyridine) Nickel(Ⅱ) and Iron(Ⅱ) complexes. The stable solid complexes were characterized with IR， UV， MS， XPS and elemental analysis. No stable complexes were formed with bidentate bis(oxazoline)(2) ins- tead of bis(oxazolinylpyridine).     

Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato) Cu(II) and Zn(II) Complexes

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(Phosphine)gold(I) Complexes of Benzenedithioles. Crystal structures of 1,2-benzenedithiolato-bis[triphenyl-phosphinegold(I)] and bis(triethylphosphine)gold(I) bis(1,2-benzenedithiolato)gold(III)

The reaction of 1,2- and 1,3-benzenedithiol C₆H₄(SH)₂ with chloro(phosphine)gold(I) complexes R₃PAuCl (R = Et, Ph) in the presence of triethylamine in tetrahydrofuran gives stable gold(I) complexes 1,2-C₆H₄(SAuPR₃)₂ [R = Et ( 1 ) and Ph ( 2 )] or 1,3-C₆H₄(SAuPPh₃)₂ ( 3 ), respectively, in high yield. The compounds have been characterized by analytical and NMR spectroscopic data. From the reaction of 1,2-C₆H(SH)₂ with Et₃P? AuCl a by-product [(Et₃P)₂Au]⁺ [Au(1,2? C₆H₄S₂)₂]^? ( 4 ) has also been isolated in low yield. The crystal structures of compounds 2 and 4 have been determined by single crystal X-ray diffraction. The gold(I) atoms in complex 2 are two-coordinate with bond angles S? Au? P of 175.2(1) and 159.5(1)°, Au? S bond distances of 2.304(1) and 2.321(1) å, and a short Au…?Au contact of 3.145(1) Å. The gold(I) atom in the cation of complex 4 is also linearly two-coordinate with a P? Au? P angle of 170.1(1) Å and Au? P distances of 2.296(3) and 2.298(3) Å. The geometry of the anion in 4 shows a square-planar coordination of gold(III) by two chelating 1,2-benzenedithiolate ligands with Au? S distances between 2.299(3) and 2.312(3) Å (for two crystallographically independent, centrosymmetrical anions in the unit cell).     

Ni(II), Pd(II), Cu(II) And Zn(II) complexes with N-(2-Pyridyl)Carbonylaniline (L), Syntheses and X-Ray Crystal structures of [Cu(L)2(H2O)2](No3)2, [Cu(L)2(H2O)2](Clo4)2 and [Zn(L)2(H2O)2](Clo4)2

Reaction of the N-(2-pyridyl)carbonylaniline ligand (L) with Cu(NO₃)₂, Cu(ClO₄)₂, Zn(ClO₄)₂, Ni(NO₃)₂ and PdCl₂ gives complexes with stoichiometry [Cu(L)₂(H₂O)₂](NO₃)₂, [Cu(L)₂(H₂O)₂](ClO₄)₂, [Zn(L)₂(H₂O)₂] (ClO₄)_2, [Ni(L)₂(H₂O)Cl](NO₃) and PdLCl₂. The new complexes were characterized by elemental analyses and infrared spectra. The crystal structures of [Cu(L)₂(H₂O)₂](NO₃)₂, [Cu(L)₂(H₂O)₂](ClO₄)₂, and [Zn(L)₂(H₂O)₂](ClO₄)₂ were determined by X-ray crystallography. The cation complexes [M(L)₂(H₂O)₂] contain copper(II) and zinc(II) with distorted octahedral geometry with two N-(2-pyridyl)carbonylaniline (L) ligands occupying the equatorial sites. The hexa-coordinated metal atoms are bonded to two pyridinic nitrogens, two carbonyl oxygens and two water molecules occupying the axial sites. Both the coordinated water molecules and uncoordinated amide NH groups of the N-(2-pyridyl)carbonylaniline (L) ligands are involved in hydrogen bonding, resulting in infinite hydrogen-bonded chains running in one and two-dimensions.     

Asymmetric Synthesis of (R)-and (S)-Moprolol

A simple and effective procedure for the enantioselective synthesis of (R)-and (S)-moprolol was described.The key step was the asymmetric synthesis of enantiopure (R)-and (S)-guaifenesin,which were synthesized from enantioenriched (R)-3-chloro-1,2-propanediol and (S)-epichlorohydrin via kinetics of hydrolysis resolution of racemic epichlorohydrin by chiral Salen-CoIIII complex.The e.e.values of both the optical compounds were above 98%,and the chemical structures of the target compounds were confirmed by 1H NMR,13C NMR,IR,and MS.     

Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato)Cu（Ⅱ） and Zn(Ⅱ） Complexes

The structures of [Cu (S₂CN (CH₂)₄)₂] (1) and [Zn₂(S₂CN‐(CH₂)₄)₄] (2) have been determined by X‐ray crystallography analysis. They are all isomorphous and triclinic, space group of P1^?, with Z = 1. The lattice parameters of compound 1 is: a = 0.63483(2) nm, b = 0.74972(3) nm, c=0.78390(1) mn, α = 75.912(2)°, β = 78.634(2)° and γ = 86.845(2)°; compound 2: a = 0.78707(6) nm, b=0.79823(6) nm, c = 1.23246(9) nm, α = 74.813(2)°, β = 73.048(2)° and γ = 88.036(2)°. The copper atom is located on a crystallographic inversion center and zinc atom lies across centers of symmetry. The Cu(II) ion has a square‐planar geometry while Zn(II) has a distorted tetrahedral geometry. The thermal gravity (TG) data indicate that no structural transitions in the two compounds were abserved and the decomposition products can adsorb gas. Also they all have a high thermal stability.