Study on Molecular Weight of Poly-β-hydroxybutyrate Biosynthesized by Methylosinus Trichosporium IMV3011

在甲烷氧化细菌Methylosinus trichosporium IMV3011细胞内生物催化合成聚-β-羟基丁酸酯（PHB）的过程中,对影响聚合物分子量的各种因素进行了研究.发现碳源、培养基组分NH4＋,NO3-,HPO24-,Mg2＋,某些导向PHB合成的关键中间产物以及PHB的提取方法均会对PHB的分子量产生影响.同时,通过对胞内PHB合成酶系中关键作用酶的活性变化进行研究,发现β-酮硫解酶催化着控制进入PHB循环入口的关键反应,而PHB分子量的变化则主要取决于PHB合成酶和PHB降解酶的协同作用.     

高效毛细管电泳-二极管阵列检测法测定土壤中的苯酚

建立了高效毛细管电泳-二极管阵列检测器测定土壤样品中苯酚的方法,研究了检测波长、缓冲体系、缓冲体系的pH值及浓度、分离电压、进样时间及压力等因素。结果表明,在温度25℃、pH=10的30mmol/L K2HPO4+0.5mmol/L十四烷基三甲基溴化铵(TTAB)运行缓冲溶液、检测波长206nm、20kV运行电压、负电压模式、0.5psi进样10s条件下,苯酚在4.2到4.4min内出峰,迁移时间和峰面积的相对标准偏差(RSD)分别为0.11%、0.28%,检出限(3Sb/Sx)为0.01mg/L。该方法成功地应用于土壤中苯酚的测定,其回收率为98.4%。     

多壁碳纳米管/聚醚胺复合物的制备

利用亲核加成逐步聚合法成功地制备了芘标记的聚醚胺(pePEA),并将其用于修饰多壁碳纳米管;采用透射电镜分析了pePEA修饰多壁碳纳米管的微观结构,并利用热重分析测定了聚醚胺的负载量.结果表明:聚醚胺对多壁碳纳米管具有较好的包覆作用,包覆层厚度约为1nm,复合物中聚醚胺的质量分数为20.4%.与此同时,多壁碳纳米管/聚醚胺复合物可在水中稳定地分散,分散液放置3周不分层,无聚集现象发生,稳定性较好.     

合成聚(丙交酯-co-ε-己内酯)的催化剂研究进展

综述了合成聚(丙交酯-co-ε-己内酯)的催化剂的研究进展;针对几种不同类型催化剂的活性、安全性及其对单体催化反应的影响等进行了评述;指出催化剂在内酯开环聚合中所起的关键作用.     

叔丁基取代二苯并-18-冠-6的合成

以二甘醇和邻苯二酚为原料制得二苯并-18-冠-6;以多聚磷酸为催化剂和溶剂,将二苯并-18-冠-6与叔丁醇反应实现叔丁基化;利用正庚烷重结晶对叔丁基化反应产物进行纯化,得到4,4′-二叔丁基二苯并-18-冠-6和4,5′-二叔丁基二苯并-18-冠-6两种对称的二叔丁基二取代苯并冠醚产品.利用红外光谱和核磁共振谱表征了二叔丁基二取代苯并冠醚产物的结构。     

微流控芯片毛细管电泳激光诱导荧光检测法测定片剂中盐酸美西律的含量

建立了微流控芯片毛细管电泳激光诱导荧光检测法测定片剂中盐酸美西律含量的方法,对衍生条件和电泳条件进行了系统的考察。盐酸美西律经异硫氰酸荧光素(FITC)40℃衍生6h,以20 mmol/L硼砂为电泳缓冲溶液,进样30s后,分离电压2000V,可在1 min内完成一次检测。方法的检出限为0.022 mg/L、线性范围0.108～1.079 mg/L、相关系数0.994,加标回收率为99.7%～102.3%,方法适用于盐酸美西律的检测和质量控制。     

乙醛酸和草酸的毛细管区带电泳分析

建立了同时测定乙醛酸和草酸的毛细管区带电泳法。考察了缓冲溶液的种类、浓度和pH以及分离电压等因素对分离结果的影响。在缓冲溶液为20 mmol/L硼砂-5.5 mmol/L邻苯二甲酸氢钾(pH 9.0)、分离电压20 kV、检测波长212 nm的优化条件下,11 min内即可实现对目标物的分离。乙醛酸和草酸分别在0.8～20 g/L和1.2～20 g/L范围内线性关系良好,相关系数分别为0.9993和0.9975;方法的检出限分别为0.2和0.4 g/L(信噪比为3);样品的加标回收率为98.3%～102.5%,相对标准偏差为0.35%～0.61%。该方法操作简便、快速、成本低廉,已应用于实际样品的分析,并获得了令人满意的结果。     

Particle Size Characterization of an Extra Fine Milled Product

The present research aims to characterize the particle size distribution of sub micron particles suspended in a liquid. The particles milled are an organic poorly water soluble crystalline product. To characterize the size of these particles, different techniques have been tested: imaging techniques (SEM, CryoTEM), static light scattering techniques, dynamic light scattering techniques, centrifugation and flow field flow fractionation. The results indicate that the studied milled particles have a primary particle size close to 180nm and there is strong evidence of larger particles which are very likely aggregates. This is clearly seen from the Cryo TEM results. All the above mentioned techniques should in principle be able to measure samples of dispersion containing particles of ca 180 nm but several are disturbed by the presence of large aggregates. It is difficult to estimate the amount of aggregate present, but most of the time one is interested in what the primary particle size distribution is. It is clear that no single piece of equipment is capable of exactly determining the particle size distribution of our samples, but the static light scattering with low shear on mixing does give a good representation of what is seen with the image analysis by cryo TEM.     

MUSIC ALGORITHM FOR LOCATING POINT-LIKE SCATTERERS CONTAINED IN A SAMPLE ON FLAT SUBSTRATE

In this paper, we consider a MUSIC algorithm for locating point-like scatterers contained in a sample on flat substrate. Based on an asymptotic expansion of the scattering amplitude proposed by Ammari et al., the reconstruction problem can be reduced to a calculation of Green function corresponding to the background medium. In addition, we use an explicit formulation of Green function in the MUSIC algorithm to simplify the calculation when the cross-section of sample is a half-disc. Numerical experiments are included to demonstrate the feasibility of this method.     

“右旋糖酐-磁性层状复合氢氧化物-氟尿嘧啶”给药系统的超分子组装表征与急毒性水平

用"前体共沉淀-离子交换插层-原位复合-溶剂转换"技术合成"右旋糖酐-磁性层状复合氢氧化物-氟尿嘧啶"(DET-MLDH-FU,DMF)运载系统,通过XRD,IR,TEM,TG表征及体外释放实验研究了DMF的物相特征与缓释性能,通过对小鼠灌胃和腹腔注射给药考察了DMF与载体MLDH的急毒性水平.结果表明,DMF等超分子的XRD与R-六方LDH衍射特征相符,是Fe3.6Fe0.9(O,OH,Cl)9型LDH及微量Fe3O4的复合晶相,DMF具有DET,MLDH与FU分级组装形成的核壳式构造.体外pH 7.35 PBS溶出介质中,DMF的药物释放遵守零级模型C-1.162×10-5=4.566×10-7t,速率常数4.566×10-7 mol-1?L?m-1.DMF,MLDH-FU及MLDH可经正常代谢排出体外,口服毒性小;腹腔注射DMF的LD50为2542.8 mg?kg-1,MLDH的LD50为1951.0 mg?kg-1,均属低毒性物质.DET的复合组装对Fe(II,III)LDH构架有抗氧化保护作用,对不同MLDH-FU粒子进行选择、分离与包封,提高MLDH-FU的缓释效果、强化MLDH的控释性能,降低给药系统DMF的急毒性水平.