A streptavidin linker layer that functions after drying

The ability of streptavidin (SA) to simultaneously bind four biotins is often used in linker layers, where a biotinylated molecule is linked to a biotin-functionalized surface via SA. For biosensor and array applications, it is desirable that the SA linker layer be stable to drying and rehydration. In this study it was observed that a significant decrease in binding capacity of a SA layer occurred when that layer was dried. For this study a SA linker layer was constructed by binding SA to a biotin-containing alkylthiolate monolayer (BAT/OEG) self-assembled onto gold. Its stability after drying was investigated using surface plasmon resonance (SPR). Approximately a quarter of the SA layer was removed from the BAT/OEG surface upon drying and rehydration, suggesting disruption of SA-biotin binding when dry. This resulted in the dried SA layer losing approximately 40% of its biotinylated ferritin (BF) binding capacity. Coating the layer with trehalose before drying was found to inhibit the loss of SA from the BAT/OEG surface. SPR showed that the trehalose-protected SA linker layer retained approximately 91% of its original BF binding capacity after drying and rehydration. Atomic force microscopy, which was used to image individual surface-bound SA and BF molecules, qualitatively confirmed these observations.     

The crystal and molecular structure of carboxylmethyltriphenylarsonium salt, Ph3 As+CH2 COO^1 11/2H2O

膦、胂叶立德能与醛、酮等通过Wittig反应合成烯烃衍生物,在有机合成中具有很大的应用价值。其反应活性与结构的关系已有深入的讨论,有关分子结构的研究工作仍在继续中。我们按文献[4]合成甲氧羰基亚甲基三苯基胂,熔点153～154℃,然后在甲醇:乙醇为1:2混合溶剂中培养单晶并进行X光晶体     

废轮胎热解炭的分析及其活化特性的研究

用常规分析方法分析了废轮胎热解炭的成分和性质，用X射线能谱分析法、压汞法、N2吸附法等测定了热解炭的孔隙结构特性，并用CO2、含2％氧气的氮气流和水蒸气等活化气体对热解炭进行活化方面的研究。结果表明，热解炭灰分和硫含量比较高；两种不同粒径热解炭的比孔容积均在r≈25 nm处有最大值；在相同活化时间和活化剂流速下，温度越高，活化炭烧失率越大，比表面积也越大；在一定温度和活化剂流速下，烧失率和比表面积随着活化时间的增加而增大；对所有试验工况，烧失率越大，活化炭比表面积也越大。总体上水蒸气活化炭与CO2的活化效果较好，而含2％O2的氮气流活化的效果则次之。活化炭与商业活性炭的比较显示，前者具有较发达的孔隙结构，在进行大分子物质吸附时，具有替代商业活性炭的潜力。     

Metal-free tandem carbene N–H insertions and C–C bond cleavages

A metal-free C–H [5 + 1] annulation reaction of 2-arylanilines with diazo compounds has been achieved, giving rise to two types of prevalent phenanthridines via highly selective C–C cleavage. Compared to the simple N–H insertion manipulation of diazo, this method elegantly accomplishes a tandem N–H insertion/S_EAr/C–C cleavage/aromatization reaction, and the synthetic utility of this new transformation is exemplified by the succinct syntheses of trisphaeridine and bicolorine alkaloids.

A metal-free C–H [5 + 1] annulation reaction of 2-arylanilines with diazo compounds has been achieved, giving rise to two types of prevalent phenanthridines via highly selective C–C cleavage.     

Cp2TiAlH4和Cp2TiBH4电子结构的CNDO研究

本文用CNDO/2方法探讨了Cp₂TiBH₄(Ⅰ)和Cp₂TiAlH₄(Ⅱ)中氢桥 (M=B、Al)的电子结构和化学键。结果表明Ⅰ和Ⅱ在HOMO组成上差异较大。HOMO(Ⅱ)中H_b^a成分较多;而HOMO(Ⅰ)则不含H_b成份,这可能是Ⅱ活泼和Ⅰ稳定的主要原因。     

［La（CCl_3COO）_3（bipy）·H_2O］_2和Tb（CCl_3CO

利用不同溶剂合成并测定了希土三氯醋酸盐与α，α＇－联吡啶（ｂｉｐｙ）不同比例的配合物（Ⅰ）Ｌａ：ｂｉｐｙ＝１：１，［Ｌａ（ＣＣｌ３ＣＯＯ）３（ｂｉｐｙ）·Ｈ２Ｏ］２和（Ⅱ）Ｔｂ：ｂｉｐｙ＝１：２，Ｔｂ（ＣＣｌ３ＣＯＯ）３（ｂｉｐｙ）２·Ｈ２Ｏ，结构测定表明配合物（Ⅰ）与（Ⅱ）均为三斜晶系，中心离子Ｌａ（或Ｔｂ）具有配位数为８的畸变四方反棱柱多面体；但是配合物（Ⅰ）形成具有对称中心的二聚体．     

水中溶解氧的测定

对近年来有关水中溶解氧的各种主要测定方法作了简介和评述,并重点介绍了传感器法的现状和发展趋势。     

A new two‐dimensional supra­molecule composed of μ‐2,6‐dimethyl­pyridine‐3,5‐dicarboxyl­ato‐κ4O3,O3′:O5,O5′‐bis­[chloro­(1,10‐phenanthroline‐κ2N,N′)zinc(II)]

In the binuclear title molecule, [Zn₂(C₉H₇NO₄)Cl₂(C₁₂H₈N₂)₂], the two metal centres are bridged by a 2,6‐dimethyl­pyridine‐3,5‐dicarboxyl­ate ligand. The binuclear unit is extended to form a two‐dimensional supra­molecular motif viaπ–π stacking inter­actions between neighbouring phenanthroline rings.     

Computer Aided Study of Mechanism of Immunoadsorbent for Myasthenia Gravis

Myasthenia Gravis (MG) is an organ specific autoimmune disease mediated by autoantibodies (AChR Ab) against the acetylcholine receptor (AChR). Literature reported that the AChR Ab can be removed by absorbent linked with tryotophan.It was studied in detail in our lab. With the aid of computer, we docked some ligandsinto AChR Ab, and the results fromscores of docking under different generations showed that therewas no specific binding between tryptophan and scFv fragment just as the binding between antigen-antibody. The interaction between Trp and immunoglobulin was a broad-spectntm binding.     

Reaction of CH3O2 and HO2: Ab initio characterization of dimer structure and vibrational mode analysis for reaction mechanisms

All species involved in the multi‐channel reaction of CH₃O₂ with HO₂ have been investigated using density functional theory (DFT). The molecular geometries for various species are optimized employing the B3LYP method implementing the 6‐311++G** basis set. The relative energies of all species are calculated at the same level theory. The results show that there are two kinds of channels: singlet and triplet. The singlet channel involves four intermediates and six transition states. The triplet channel includes two intermediates and two transition states. There are four kinds of reaction products: CH₃OOH + ¹O₂, CH₃OH + O₃, CH₄ + 2O₂, and CH₃OOH + ³O₂. The vibrational mode analysis is used to elucidate the relationships of the intermediates, the transition states, and the products. The extensive investigation shows that the reaction mechanism is reliable. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006