Design and synthesis of heterobimetallic donor-acceptor chemodosimetric ensembles for the detection of sulfhydryl-containing amino acids and peptides

A competitive indicator displacement assay has been successfully developed for the ratiometric determination of sulfhydryl-containing amino acids and peptides using heterobimetallic donor-acceptor complexes as chemodosimetric ensembles. Chromotropic cis-[ML2(CN)2](M = FeII, RuII, OsII; L = diimine) are used as signaling indicators and PtII(DMSO)Cl2 acceptor moiety is used as the receptor for the sulfhydryl-containing analytes. A series of three heterobimetallic donor-acceptor complexes: cis-FeII(bpy)2[CN-PtII(DMSO)Cl2]2 (1), cis-Ru(II)(bpy)2[CN-PtII(DMSO)Cl2]2 (2) and cis-Os(II)(bpy)2[CN-PtII(DMSO)Cl2]2 (3) are synthesized and characterized by X-ray crystallography. All the three ensembles are able to produce specific colorimetric/fluorimetric responses to sulfhydryl-containing amino acids (cysteine, homocysteine and methionine) as well as the sulfhydryl-containing small peptide glutathione. The mechanism of the competitive displacement assay is evaluated by examining the thermodynamics of formation of the donor-acceptor linkage and adducts between the acceptor metal and the sulfhydryl-containing analytes as well as by systematic variation of the donor and acceptor metals in the chemodosimetric ensembles.     

ZSM-5分子筛催化剂酸性对积炭的影响

研究了几种分子筛在乙基化反应中的积炭过程,并与分子筛的酸性、孔结构等参数关联,阐明了ZSM-5分子筛催化剂的酸中心对积炭起着主要作用。酸强度越高,越容易积炭,酸量越大积炭越多。积炭的形成部位与酸中心在晶内外的分布关系密切。分子筛外表面酸中心比晶内的更易生成积炭,体现了积炭的择形性。     

迭代目标转换因子分析法在光度分析中的应用研究——用三溴偶氮氯膦同时测定15个稀土元素

以三溴偶氮氯膦为显色剂,应用迭代目标转换因子分析光度法对15个稀土元素混合物合成样品进行同时测定,结果的平均相对误差为2.9％～5.6％。对标准数据阵的构成。主因子数的确定以及组份间浓度比对计算结果的影响等问题作了讨论。     

火花源质谱法定量分析高纯氧化钬和氧化镥中痕量元素

本文采用相对灵敏度因子，研究了９９．９９９％－９９．９９９９％的Ｈｏ２Ｏ３和Ｌｕ２Ｏ３中４０余种杂质元素的火花源定量分析方法，讨论了谱线干扰。做了加入回收及生理性实验，大多数元素的相对标准偏差在３０％以内，检测下限为０．００ｘμｇ／ｇ。     

Synthesis of a slow‐release and superabsorbent nitrogen fertilizer and its properties

A slow‐release and superabsorbent nitrogen fertilizer (SSNF) was synthesized by aqueous solution copolymerization of acrylic acid and maleic anhydride using N,N′‐methylene bisacrylamide as a crosslinker, ammonium persulfate and sodium sulfite as an initiator in the presence of urea. The effects on water absorbency such as amount of crosslinker, initiator, urea and maleic acid, degree of neutralization, etc. were investigated. To improve slow release and water retention properties, the product was surface‐crosslinked with trihydroxymethyl propane glycidol ether (6360). The nitrogen content of the SSNF synthesized under optimal conditions was 28.5%, and the water absorbencies were about 900 (g/g) in distilled water and 180 (g/g) in tap water. The nitrogen slow release behavior of the SSNF in water and water retention capacity of the soil with SSNF were also investigated. The results showed that the surface‐crosslinked product not only had good slow release property but also excellent soil moisture preservation capacity, which could effectively improve the utilization of fertilizer and water resources simultaneously. The results of the present work indicated that the SSNF could be found an application in agriculture and horticulture, especially in drought‐prone areas where the availability of water is insufficient. Copyright © 2006 John Wiley & Sons, Ltd.     

枸杞子中红色素的提取及稳定性

枸杞子中红色素的提取及稳定性伍明，王杰，闪春霞，任仲皎，宋锡瑾，詹国庆（中南民族学院化学系武汉４３００７４）关键词枸杞，色素，液泛提取法枸杞子为茄科枸杞属植物的果实，具有补肾养肝，润肺明目以及调节机体免疫力，抑制肿瘤生长和细胞突变，延缓衰老及抗脂肪肝...     

Bond strength and bond angles for hybrid orbitals composed of arbitrary sets of orbital angular momentum quantum number

According to the formulas obtained in the preceding paper, it may be used for all types of the hybridization with any set of azimuthal quantum numbers l, l = 0 through l = 5, and a complete theoretical data of bond angles and bond strengths are shown in this paper.     

Synthesis,characterization and properties of the α-K7[GaW11Ti(O2)O39]·11H2O heteropolyanion

The peroxotitanium-substituted heteropolytungstate -K₇[GaW₁₁Ti(O₂)O₃₉]·11H₂O has been prepared and characterized by elemental analysis, i.r., u.v., ¹⁸³W-n.m.r. and by electrochemistry. The ¹⁸³W-n.m.r. spectrum consists of six lines with intensity ratio 2:2:1:2:2:2, indicating that the TiO₂ occupies the empty octahedral site of the -K₉[GaW₁₁O₃₉]·xH₂O anion forming a polyanion with C _s symmetry. The characteristic charge-transfer absorption band O^2– ₂ Ti at 385 nm occurs in the u.v. spectrum. The polargraphic reduction potential of O^2– ₂ at ca. + 0.95 V has been determined.     

三(邻甲苯基)氢化锡与1-乙炔基环戊醇和1-乙炔基环己醇的加成物的合成及晶体结构

通过三(邻甲苯基)氢化锡与1-乙炔基环己醇和1-乙炔基环戊醇发生加成反应,得到两个加成物:(Z)-1-[2-(三-邻甲苯基锡基)乙烯基]环戊醇(1)和(Z)-1-[2-(三-邻甲苯基锡基)乙烯基]环己醇(2).通过元素分析、红外光谱和核磁共振氢谱等手段对其结构进行了表征.用X射线单晶衍射测定了加成物1和2的晶体结构.二者均为具有分子内O→Sn弱配位的扭曲四面体结构.1属于单斜晶系,P21/n空间群,晶胞参数:a=1.0496(2)nm,b=1.7658(4)nm,c=1.3193(3)nm,β=90.60(3)°,V=2.4451(8)nm3,Z=4,R=0.0317,wR=0.0820.2属于三斜晶系,空间群P1,晶胞参数:a=O.85592(17)nm,b=0.93016(19)nm,c=1.6368(3)nm;α=83.76(3)°,β=82.69(3)°,γ=78.05(3)°;V=12600(4)nm3,Z=2,R=0.0377,wR=O.1030.     

Trichosanthin's interfacial interactions with phospholipids: a monolayer study

Lipid monolayer at the air/water interface, as half a membrane, was used here to investigate the interaction between trichosanthin (TCS), a ribosome inactivating protein, and phospholipid membrane. First, the protein adsorption experiments showed that the negatively charged DPPG caused obvious enrichment of TCS beneath the monolayer, indicating electrostatic attraction between TCS and the negatively charged phospholipid. Second, when TCS was incorporated into the phospholipid monolayer, it could not be completely squeezed out until the monolayer collapsed. The results were demonstrated to be irrelative with the phospholipid headgroup, suggesting a strong hydrophobic force between TCS and phospholipid hydrocarbon chain was involved in the interaction. Third, the protein/membrane interaction was further studied with fluorescence microscope. The results showed that TCS could penetrate into both the condensed and the fluid phase of the DPPG monolayer under low pH condition and eventually resulted in a homogeneous phospholipid phase. The breakage of ordered packing of phospholipid by TCS may be responsible for this homogenizing effect.