临床肝素类药物酶解分析二糖组成

肝素是一类结构复杂的高分子糖类,以N-硫酸、6-O硫酸氨基葡萄糖和2-O硫酸艾杜糖醛酸为主要成分组成二糖。常见的肝素注射液是以未分级肝素为原料纯化灭菌制备而来,在临床上使用更为广泛的是将肝素降解得到的低分子片段,低分子肝素保留了肝素糖链基本结构,但是不同制备工艺导致其具有不同的还原及非还原端。本研究以肝素类药物为研究对象,使用肝素裂解酶玉,域及芋将肝素注射液、低分子肝素注射液(达肝素、那屈肝素、依诺肝素)、化学合成的类肝素(磺达肝素)进行酶催化降解产生二糖,结合强阴离子交换色谱( Strong anion exchange high performance liquid chromatography,SAX-HPLC)以及紫外检测器在线分析,使用市售肝素二糖标准品确定各种二糖结构。此外,使用反向离子对色谱和电喷雾质谱联用分析磺达肝素中的甲基二糖以及达肝素和那屈肝素中的脱氨二糖结构,为肝素以及类肝素药物的质量控制提供更为精确的结构信息。     

菲涅耳双棱镜放置方式对实验结果的影响

用菲涅耳双棱镜测光波波长实验是大学物理实验中的基础实验,它是用分波面法获得相干光的典型实验. 在实验装置中,双棱镜的放置方式有2种,即棱镜棱脊面向单缝还是背向单缝. 本文通过详细的理论推导,得出双棱镜的放置方式对实验结果没有影响的结论,而且这个结论已得到了实验的证实.     

Homopolymerization of N-pyrimidinyl acrylamide

Homopolymerization of N-pyrimidinyl acrylamide(NPA)was reported for the first time.The polymer(polyNPA)was soluble only in acidic media and fluoroalcohols,and only in fluoroalcohol was homogeneous polymerization of NPA feasible.~1H NMR analysis proved that a 1:1 H-bonding complex could be formed between NPA andα,α-bis(trifluoromethyl)phenyl propan-2-ol (BTMP).Cumyl dithiobenzoate mediated reversible addition-fragmentation chain transfer(RAFT)polymerization of NPA in BTMP was carried out.~1H NMR analyses proved that the molecular weight increased linearly with the monomer conversion.The polymer prepared in conventional solvents was atactic while in protic media the syndiotacticity was slightly enhanced.     

100MeV负氢回旋加速器高频冷模腔的理论与实验研究

在回旋加速器中,高频系统为带电粒子加速提供能量,高频谐振腔作为高频系统中的关键部件,它性能的好坏直接决定着粒子是否能够被加速,所以,高频谐振腔的设计非常关键.在100MeV负氢回旋加速器的设计中,在空间限制的同时,要求加速电压从中心区的60kV到出引区的120kV变化,这对谐振腔的设计提出了很高的要求.基于上述条件,本工作利用有限差分法的软件CST MICR0wAVESTUDIO设计的双内杆结构的44MHz高频谐振腔初步设计完成,根据初步设计的结论,加工与实际腔体尺寸1:1模型,模型高频参数测量的结果与CST MICROWAVE STuDIO的计算相吻合,结果是可信的.     

Three Novel Terpenoids from Schisandra pubescens var. pubinervis

Three new terpenoids, pubinernoids A–C ( 1 – 3 ), together with six known sesquiterpenoids, were isolated from the leaves and stems of Schisandra pubescens var. pubinervis. The structures of the new compounds were established on the basis of extensive spectroscopic analyses, including application of 2D‐NMR spectroscopic techniques. A plausible formation of the sesquiterpenoid 2 is proposed (Scheme 2), starting from guaianediol ( 4 ) as the biogenetic precursor, which was also present in the extract.     

Synthesis of PAN/SnCl2 composite as Li-ion battery anode material

A novel process was proposed to synthesize the pyrolytic polyacrylonitrile (PAN)/SnCl₂ composite anode material for Li-ion batteries. The preparation started with the dissolution of PAN and SnCl₂ in dimethylformamide (DMF), followed by drying of the solution and pyrolysis of the dried mixture of PAN and SnCl₂ at 300 °C, leading to homogenous dispersal of SnCl₂ in pyrolytic PAN, which becomes conducting polymer matrix. The composite presented stable cycling capacity of about 490 mAh/g. It is demonstrated that SnCl₂, which has been considered to be an inactive electrode material, can become active by the proposed composite technique. This paves the promising way to prepare electrode materials for Li-ion batteries.     

Low potential electrosyntheses of free‐standing poly(dibenzofuran) films in mixed electrolytes of boron trifluoride diethyl etherate and trifluoroacetic acid

Free‐standing poly(dibenzofuran) (PDBF) films were synthesized electrochemically by direct anodic oxidation of dibenzofuran in mixed electrolytes of boron trifluoride diethyl etherate (BFEE) containing certain amount of trifluoroacetic acid (TFA). The oxidation potential of dibenzofuran in pure BFEE was measured to be only 1.31 V versus saturated calomel electrode (SCE). This value was much lower than that determined in acetonitrile + 0.1 mol L^?1 TBATFB (2.14 V vs. SCE). The addition of TFA to BFEE can further decrease the oxidation potential of the monomer to 1.07 V versus SCE in the mixed electrolyte of BFEE + 30% TFA. PDBF films obtained from this medium showed good electrochemical behavior, good electrochromic properties, and good thermal stability with conductivity of 10⁰ S cm^?1. FTIR and ¹H NMR spectra showed that the polymer was grown mainly via the coupling of the monomer at C₍₃₎ C₍₁₀₎ or C₍₄₎ C₍₉₎ positions (Scheme 1). As‐formed PDBF films were partly soluble in tetrahydrofuran (THF) or chloroform. Fluorescent spectral studies indicated that either soluble or PDBF in solid state was a good blue light PDBF emitter. To the best of our knowledge, this is the first report that free‐standing PDBF films can be electrodeposited. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1125–1135, 2006