聚氨酯分子印章的制备和表征

“软平板印刷”微结构制备技术为微米和亚微米器件的制备提供了一条新的途径 [1] ,已被电子学家和材料学家所应用 ,近年来进入了生物学领域[2 ] .本实验室将这一方法与生物分子电子学相结合 ,提出了用于 DNA芯片在片合成的分子印章法 [3,4 ] .分子印章法的实质是接触压印与组合化学相结合的固相界面反应 .聚二甲氧基硅氧烷 ( PDMS)是一种软印刷的优良材料 [5] ,但是由于其疏水性和较差的机械性能 ,必须对其进行改性才能用来制备 DNA分子印章 [6 ] .　　聚氨酯作为一种功能材料 ,由于分子中交替的软、硬链段及其不同的热动力学性能而形成…     

Studies on the refolding of the reduced-denatured insulin with size exclusion chromatography

The refolding of the reduced-denatured insulin from bovine pancreas was investigated with the size exclusion chromatography (SEC). It was shown that the reduced-denatured insulin originally denatured with 7.0 mol·L-1 guanidine hydrochloride (GuHCI) or 8.0 mol·L-1 urea could not be refolded with a non-oxidized mobile phase. Although the oxidized and reduced glutathione (GSSG and GSH) were employed in the oxidized mobile phase, the reduced-denatured insulin still could not be renatured. However, in the presence of 2.0 mol·L-1 urea in the oxidized mobile phase employed, the reduced-denatured insulin can be refolded with SEC, and the aggregation of denatured insulin can be diminished by urea. In addition, the disul-fide exchange of reduced-denatured insulin also can be accelerated with GSSG/GSH in the oxidized mobile phase. The three disulfide bridges of insulin were formed correctly and the reduced-unfolded insulin can be renatured completely. The results were further tested with re-versed-phase liquid chromatography (RPLC) and hydrophobic interaction chromatography (HIC).     

一种分离抗凝血酶Ⅲ的高效亲和色谱填料的制备及表征

以聚甲基丙烯酸环氧丙酯微球 ( PGMA)为基质 ,利用还原氨化方法将肝素键合在其表面上 ,得到一种以肝素为配基的高效亲和色谱填料 ,该填料对抗凝血酶 的亲和容量为 1 .2 mg/g,对抗凝血酶 和人血清白蛋白的回收率分别为 96.9%和 94 .4 % .利用前沿色谱法测定了肝素与抗凝血酶 之间的表观解离常数为 1 .96× 1 0 - 5mol/L.利用该填料可直接从人血浆中分离出抗凝血酶     

A New Bislabdane-type Diterpenoid from Cunninghamia lanceolata

Cunninghmia lanceolata Hook. is a traditional Chinese medicine used for thetreatment of hernia, arthritis and strangury. its chemical constituents have beenexamined]' 2' 3' '. In a previous paper we reported a bislabdane-type diterpenoidlanceolatic acid from the roots of the plant 5. Further chemical studies on this plantled to the isolation of another new bislabdane-type diterpenoid, named lanceolatin(I ).Compound I was obtained as white amorphous powder. mp 232-234 'C, [a]."-24 (c 0. 10, C…     

Link between the kinetic‐ and exchange‐energy functionals in the generalized gradient approximation

An approximate kinetic‐energy functional of the generalized gradient approximation form was derived following the “conjointness conjecture” of Lee, Lee, and Parr. The functional shares the analytical form of its gradient dependency with the exchange‐energy functionals of Becke and Perdew, Burke, and Ernzerhof. The two free parameters of this functional were determined using the exact values of the kinetic energy of He and Xe atoms. A set of 12 closed‐shell atoms was used to test the accuracy of the proposed functional and more than 30 others taken from the literature. It is shown that the conjointness conjecture leads to a very good class of kinetic‐energy functionals. Moreover, the functional developed in this work is shown to be one of the most accurate despite its simple analytical form. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002     

A new approach to the synthesis of α-chlorocycloalkanones

α-Chlorocycloalkanones(Ⅳ) were synthesized from cycloalkanones via potassiumα-oxocycloalkylsulfonates(Ⅱ).A two-step mechanism was proposed to explain the formation ofⅣfromⅡ.     

Ring-opening Polymerization of e-Caprolactone Using Lanthanide Tris(4-tert-butylphenolate)s as a Single-component Initiator

The ring-opening polymerization of e-caprolactone (CL) initiated by novel single lanthanide tris(4-tert-butylphenolate)s [Ln(OTBP)3] is reported. Single-component La(OTBP)3 can effectively prepare polycaprolactone (PCL) with over 90% yield and viscosity average molecular weight about 60 x 10 under quite mild conditions: molar ratio of CL to initiator is 1000, 60 C, 2 h in toluene. Mechanism study indicates that the monomer inserts into the growing chain via the break of acyl-oxygen bond of CL.     

A New Application of Carbon Nanotubes Constructing Biosensor

Carbon nanotubes used for constructing biosensor was described for the first time. Single-wall carbon nanotubes (SWNTs) functionalized with carboxylic acid groups were used to immobilize glucose oxidase forming a glucose biosensor. The biosensor response can be determined by amperometric method at a low applied potential (0.40V).     

An application of the phosphine-catalyzed [4 + 2] annulation in indole alkaloid synthesis: formal syntheses of (+/-)-alstonerine and (+/-)-macroline

[reaction: see text] An application of the phosphine-catalyzed [4 + 2] annulation in the formal synthesis of alstonerine and macroline is reported. A phosphine-catalyzed [4 + 2] reaction between imine 7a and allene 8 formed the D ring of the target indole alkaloids. A subsequent intramolecular Friedel-Crafts acylation provided the C ring of the bridged tetracycle. Deprotection, followed by methylation of the bridged nitrogen, deoxygenation of the C6 ketone, and reduction of the C16 carbethoxy group provided the previously known intermediate 3.