金属离子在液相氧化中的催化作用 XI.金属酞菁(MPc,M=Co、Fe)在异丙苯液相氧化中的催化作用

研究了MPc(M=CO、Fe)在异丙苯液相氧化中的催化作用,并考察了Py、bPy和菲绕啉等含N配体对MPc催化性能的影响.发现反应遵循配位-链锁反应机理.反应速度对异丙苯为1.5级,对催化剂为0.5级.反应活化能分别为53.1kJ/mol.(CoPe)和43.9 kJ/mol.(FePc).在所选择的反应条件下,异丙苯转化率较低(小于35%),生成过氧化氢异丙苯选择性约为100%.加入第五配体可使诱导期消失.电子光谱和反应动力学结果同时表明,反应是由O_2的配位活化引发的,ESR结果证明酞菁环的电子可和金属离子进行交换.     

聚对苯二甲酸乙二醇酯－己内酯／聚酚氧树脂共混体系荧光光谱

聚对苯二甲酸乙二醇酯－己内酯／聚酚氧树脂共混体系荧光光谱张瑞云，罗筱烈，马德柱（中国科学技术大学材料科学与工程系合肥２３００２６）关键词共混物，相容性，荧光光谱，激基复合物荧光光谱分析作为一种强有力的手段，为在更小的尺寸范围内研究共混体系相容性提供了...     

铕(Ⅲ)-β-二酮-碱三元配合物的合成及其光谱研究

本文合成了铕(Ⅲ)与五种β-二酮(乙酰丙酮Acac、苯甲酰丙酮BA、二苯甲酰甲烷DBM、三氟乙酰丙酮TFA和噻吩甲烷三氟丙酮TTA)和碱(邻菲罗啉phen、哌啶pip、NaOH)的十三种固体三元配合物,其组成为Euβ_3·phen或C~+[Ruβ_4]~-,(C~+=Hpip~+或Na~+)测定了它们的红外、紫外和荧光光谱,观察到当第二配体相同时,随着β-二酮分子中的甲基被苯基、三氟甲基或噻吩基取代时,其配合物的相对荧光强度增大,第二配体的性质与影响配合物的相对荧光强度,表明分子中离域π键范围的大小和含该键平面的刚性是影响其荧光性质的重要因素。     

高效液相色谱法制备罗汉果甜甙Ⅴ标准品

 为深入研究罗汉果中功能成分的药理药效,进一步开发罗汉果中的有效成分,将罗汉果鲜果的水提物以AB-8吸附树脂分离、D-280离子交换树脂脱色后,利用半制备高效液相色谱法得到三萜皂甙类化合物 罗汉果甜甙Ⅴ标准品,纯度达98.5%。色谱柱为Alltech Econosphere NH2柱;流动相为乙腈-水(体积比为68∶32)溶液,流速5 mL/min ;检测波长203 nm;柱温40 ℃。此方法具有操作简便、重现性好、产品纯度高等优点。     

PET和TCL共聚酯共混体系相容性

利用热分析研究了聚对苯二甲酸乙二醇酯（ＰＥＴ）与对苯二甲酸乙二醇酯（ＥＴ）－己内酯（ＣＬ）共聚物（ＴＣＬ）共混体系的相容性，同时考察了体系中ＴＣＬ组成分布不均一性及高温热处理对体系相容性的影响。     

Biomimetic polymer/apatite composite scaffolds for mineralized tissue engineering

The material surface must be considered in the design of scaffolds for bone tissue engineering so that it supports bone cells adhesion, proliferation and differentiation. A biomimetic approach has been developed as a 3D surface modification technique to grow partially carbonated hydroxyapatite (the bonelike mineral) in prefabricated, porous, polymer scaffolds using a simulated body fluid in our lab. For the rational design of scaffolding materials and optimization of the biomimetic process, this work focused on various materials and processing parameters in relation to apatite formation on 3D polymer scaffolds. The apatite nucleation and growth in the internal pores of poly(L-lactide) and poly(D,L-lactide) scaffolds were significantly faster than in those of poly(lactide-co-glycolide) scaffolds in simulated body fluids. The apatite distribution was significantly more uniform in the poly(L-lactide) scaffolds than in the poly(lactide-co-glycolide) scaffolds. After incubation in a simulated body fluid for 30 d, the mass of poly(L-lactide) scaffolds increased approximately 40%, whereas the mass of the poly(lactide-co-glycolide) scaffolds increased by about 15% (see Figure). A higher ionic concentration and higher pH value of the simulated body fluid enhanced apatite formation. The effects of surface functional groups on apatite nucleation and growth were found to be more complex in 3D scaffolds than on 2D films. Surprisingly enough, it was found that carboxyl groups significantly reduced the apatite formation, especially on the internal pore surfaces of 3D scaffolds. These findings are critically important in the rational selection of materials and surface design of 3D scaffolds for mineralized tissue engineering and may contribute to the understanding of biomineralization as well.SEM micrograph of a poly(L-lactide) scaffold.     

Parameters concerning the preparation and performance of a magnetic microparticle antibody

We have described Magnetic Microparticle Antibodies and Their Application to RIAs in a recently published paper¹. In this article operative parameters for the preparation of a magnetic second antibody (MSA-II) including results of purification of donky anti-rabbit (DxR) serum by an (NH₄)₂SO₄ precipitation method, rates of recovery of products in preparation of magnetic nucleus (MN, Fe₃O₄ microparticle), in distillation of acrolein (AL) and in preparation of polyacrolein magnetic particle (PAMP), change in pH value of suspension irradiated before and after⁶⁰Co -irradiation and volume of wet sediment in separation of magnetic particles by a magnetic separator, etc., as well as correlation of levels of quality control (QC) sera obtained with liquid-phase double antibody assay (LDA) and MSA-II assay during four years were supplementarily summarized. These operative parameters would be helpful to mastering the procedures for preparation and/or use of the magnetic particles. The better correlation of levels of QC sera for both the assays showed the reliability of the magnetic antibody.This paper is a progress report of the Technical Contract No. 8955/R0/Deferred Programme Acrivities (DPA) 1994 from 1996-02-15 to 1997-02-14, supported by Intemational Atomic Energy Agency.     

Cache-aware volume rendering methods with dynamic data reorganization

Journal of Visualization -  We present two cache-aware methods for accelerating volume rendering on graphics processing units (GPUs). The proposed methods extend a previous method such...     

A new naphtho-<Emphasis Type="Italic">γ</Emphasis>-pyrone from mangrove endophytic fungus ZSU-H26

A new naphtho-γ-pyrone, 5-hydroxy-6,8-dimethoxy-2-benzyl-4H-naphtho[2,3-b]-pyran-4-one (1), together with three known compounds 5,7-dihydroxy-2-methylbenzopyran-4-one (2), 3,5-dihydroxy-2,7dimethylbenzopyran-4-one (3) and cyclo(Tyr-Tyr) (4) were isolated from the mangrove endophytic fungus Phomopsis sp. ZSU-H26 obtained from the South China Sea. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopic techniques. Primary bioassays showed that 1 exhibited cytotoxicity against HEp-2 and HepG2 cells with IC₅₀ values of 10 and 8 μg/mL, respectively.