低分子量聚谷氨酸的制备及其在眼科靶向药物中的应用研究

人体角膜难以吸收分子量较大的药物分子,为了减少高毒药物治疗眼表疾病时经角膜吸收导致的眼内副作用,设计了丝裂霉素C的L-聚谷氨酸衍生物高分子前药。为了减少市售链状大分子聚谷氨酸修饰后,丝裂霉素C被其包缠导致的药效降低,将市售的L-聚谷氨酸先进行定量水解,获得了一系列较低分子量的L-聚谷氨酸(1~5 k),通过电泳法确证其分子量,并将其应用制备了系列低分子量L-聚谷氨酸衍生物高分子丝裂霉素C前药。     

生物法聚谷氨酸工艺问世

据报道,南京工业大学成功开发出γ-聚谷氨酸制备及其应用技术。该项目采用了具有创新性的生物方法制备聚谷氨酸,其菌种与发酵工艺达到国际先进水平,技术优势显著,应用前景看好。自2 0世纪90年代以来,开发绿色化学产品已成为化学工业发展的趋势,而聚合氨基酸系列产品的开发也由此崭露头角。γ-聚谷氨酸是一种由微生物合成的聚氨基酸,具有优良的生物相容性和生物可降解性,在生物体内降解为谷氨酸而直接被吸收,可用作生物医用材料。另外,因聚谷氨酸吸水性强,易修饰,在自然界中可迅速降解,不会造成环境污染,可用于化妆品、食品和药物传输领域。…     

γ-聚谷氨酸/壳聚糖负载紫杉醇复合纳米粒子的制备与研究

紫杉醇是美国FDA批准的用于治疗卵巢癌和乳腺癌的药物。本研究以γ-聚谷氨酸(γ-PGA)/壳聚糖(CS)为研究对象,制备壳聚糖/γ-聚谷氨酸复合纳米粒子。选择紫杉醇(TXL)作为模型药物,根据紫杉醇的浓度变化研究复合纳米粒子的载药性能。红外光谱表征和差示扫描量热分析及电子透射电镜证实药物包埋成功。     

谷氨酸类聚合物的合成方法及其应用

主要介绍了谷氨酸类聚合物的制备方法和应用，包括聚γ谷氨酸、聚谷氨酸-γ-苄酯、聚谷氨酸-γ-甲酯、聚谷氨酸-天冬氨酸共聚物、聚谷氨酸-γ-苄酯-聚乙二醇共聚物。     

聚谷氨酸——新型生物刺激剂在农业上的应用

介绍聚谷氨酸在农业上的应用,并对聚谷氨酸复混肥对油菜产量、生物性状的影响进行分析,对施用聚谷氨酸复混肥的油菜的经济效益进行评价。结果表明,施用聚谷氨酸复混肥的油菜实际产量、生物性状、经济效益均优于施用普通复混肥。     

生产部开展聚谷氨酸尿素产品建标试验工作

<正>为顺利开展聚谷氨酸检测试验工作,7月11日,生产部技术中心人员到厂家南京轩凯生物科技有限公司就聚谷氨酸的检测进行了深入交流,详细了解了聚谷氨酸物理化学特性,原料聚谷氨酸的质量状况等相关知识。据了解,随着公司第二代新型增效尿素——聚谷氨酸尿素产品开发,生产部需组织建立聚谷氨酸尿素产品及原料助剂企业标准,作为企业生产和质量检验的依据。聚谷氨酸尿素是在尿素生产工艺中添加聚谷氨酸增效剂制成的增值尿素,聚谷氨酸含量的检测通常采用高校液相色     

γ-聚谷氨酸的保湿性研究

采用体外称重法考察了γ-聚谷氨酸溶液的浓度、p H对其保湿性的影响,并比较了γ-聚谷氨酸与透明质酸、甘油水溶液的保湿性差异。研究结果表明,γ-聚谷氨酸溶液的浓度越高,保湿效果越好,但二者不成正比例关系。γ-聚谷氨酸溶液在中性和偏碱性环境下的保湿性明显优于酸性和偏酸性环境。0. 5%γ-聚谷氨酸、透明质酸和甘油水溶液都具有良好的保湿性,其保湿性排序为:透明质酸γ-聚谷氨酸甘油。     

γ-聚谷氨酸的微生物合成及应用

γ-聚谷氨酸是一种多功能、可降解的生物高分子,可由微生物发酵合成,近年来受到广泛关注。文章综述了γ-聚谷氨酸的化学结构、制备方法(重点是微生物发酵合成法)、产生菌及相应发酵条件、微生物合成γ-聚谷氨酸的分子机制及γ-聚谷氨酸在医药、食品、化妆品、农业、工业等方面的应用,并对γ-聚谷氨酸研究的发展前景作了展望。     

γ-聚谷氨酸的生物合成及应用

聚谷氨酸是一种可降解的生物高分子 ,可由微生物生物聚合而得到。综述了聚谷氨酸的生物合成方法、高吸水性聚谷氨酸制备技术以及在农业、医药、化工等领域的应用     

γ-聚谷氨酸的特性、生产及应用

γ-聚谷氨酸是-种谷氨酸同聚物,可由微生物发酵得到.γ-聚谷氨酸具有水溶性、可生物降解性和可食用性且对人和环境无毒的诸多优点,这使得γ-聚谷氨酸及其衍生物在食品、化妆品、医药和农业等领域具有广阔的应用前景.本文综述了γ-聚谷氨酸的化学结构、性质、生产方法及其用途.     

乙烯酮(双乙烯酮)下游产品废水的治理技术

乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。     

几种乙炔加压设备性能的比较

阐述并比较了几种加压设备在乙炔加压清净过程中的性能和特点。     

三种煤样燃烧热的测定

本文通过三个厂家提供的三种煤样燃烧热的测定,由测定结果综合得出3号煤样燃烧最完全、燃烧热也最大,是三个煤样中最好的一种。     

Semi-empirical equation of state of metals. Equation of state of aluminum

A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO₂) of density 0.08 g/cm³. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008.     

水泥水化热测定方法综述

水泥水化热是中、低热水泥和核电工程用水泥的一项关键的技术指标。全球范围内测定水泥水化热的方法有溶解法、直接法/半绝热法、等温传导量热法三种。本文总结了中、美、欧相关方法标准,对其测试原理、仪器设备、试验过程等方面进行了比对,并对其在领域的应用做了简单的概括。     

Calorimetric and Computational Study of Enthalpy of Formation of Diperoxide of Cyclohexanone

A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out.     

我国聚碳酸酯工业发展概况

介绍我国聚碳酸酯生产能力和消费需求,对聚碳酸酯在信息工业中的应用作了简短介绍     

小议汽车涂装工艺设计对涂装成本的影响

论述了涂装工艺设计对涂装设备投资、涂装生产成本的影响。     

Effect of degree of deacetylation of chitosan on the kinetics of ultrasonic degradation of chitosan

The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003     

Measurement of the gradient of viscosity with composition of mixtures of non-ideal gases

A perturbation viscometer is a differential capillary viscometer that measures the logarithmic viscosity gradient of the viscosity-composition curve for gas mixtures. Measurements are made at different gas mixture compositions. Integration of the logarithmic viscosity gradients measured over the full composition range gives the mixture viscosity relative to the viscosity of one of the pure components of the gas mixture. This method is attractive because, for measurements of equal precision, integration of the gradients is potentially an order of magnitude more precise than measurement of the viscosities directly. It can also work at high and low temperatures and perhaps high pressures.The perturbation viscometer has been used to make measurements on ideal gas mixtures at ambient and elevated temperatures. The situation is more complicated when the gas mixtures are non-ideal. Extra effects due to density differences, molar volume change on mixing and differential thermal expansion may be measured in addition to the desired viscosity change producing systematic errors in the results. Thus, a more sophisticated apparatus is required. The standard perturbation viscometer has been modified to separate out the extra effects to permit measurement of the true change in viscosity. In addition, the theoretical operation of the modified apparatus has been revised to account for the design changes to permit calculation of the viscosity-composition profiles from the results.The apparatus has been tested using helium-HFC-125 mixtures and two new viscosity-composition profiles are presented for these mixtures at 23 and . Internal consistency tests have been used to confirm that the data produced are of high quality with an estimated uncertainty in the viscosity ratio data at of 0.9% and at of 1.5%.