不同水解方式下蚕丝丝素蛋白材料的止血性能

为提升蚕丝丝素蛋白材料的止血性能,采用盐解和酶解2种方式水解蚕丝丝素蛋白,通过冷冻干燥法制备得到2种蚕丝丝素蛋白材料。通过凝胶过滤色谱、水溶性实验、凝血因子实验、血小板黏附实验、酶联免疫吸附实验等分析了2种蚕丝丝素蛋白材料的分子质量、水溶性和止血效果。结果表明:与盐解法相比,酶解所得材料具有较低的分子质量和较好的水溶性,有利于激活凝血因子Ⅻ从而对内源性凝血起到促进作用,止血时血小板黏附量和血小板第4因子含量会明显增加,大鼠肝部出血量减少且出血时间缩短,其止血效果优于市售云南白药。

水解方法对疏水改性聚丙烯酰胺的性能影响

采用水溶液自由基胶束共聚法,通过氧化还原体系引发丙烯酰胺与自制功能单体聚合,以均聚后水解与均聚共水解方法分别制得疏水改性聚丙烯酰胺(HMPAM)。通过探针芘的荧光光谱、扫描电镜和表观粘度测定等手段,表征了HMPAM溶液中疏水缔合作用及分子聚集形态,研究了不同水解方法导致的浓度、温度、矿化度对HM-PAM溶液流变性能的影响。结果表明,均聚后水解产物分子量(1 000多万)大于均聚共水解产物的分子量,并且其在盐水溶液中存在明显的临界缔合浓度。但是均聚共水解产物产物在高温、高矿化度及97 d的老化实验条件下,其粘度保留率高于均聚后水解产物。

α-噻吩甲酰三氟丙酮-哌啶铈对DNA和磷酸二酯键模型物(BDNPP)的作用研究

CeTTA4·HP(here,TTA=2-Thenoyltrifluoroacetone,HP=Piperidine)has been synthesized and characterized.we found that the CeTTA4·HP complex can cleave circular plasmid pBR322 DNA at pH7.2 and 37℃.In addition,we choose BDNPP(bis(2,4-dinitro phenyl)-phosphate)as a model compound to further study the cleavage mechanism for pBR322 DNA.From the second-order kinetics equation,we prove indirectly the mechanism may be hydrolytic cleavage.

甘薯中淀粉测定方法的比较与优化

淀粉含量的测定方法多种多样,但是关于甘薯淀粉的测定方法,目前尚无统一标准。通过对甘薯干基获得方式,淀粉水解方式以及还原糖测定方式3个主要因素对甘薯淀粉含量测定结果的影响进行探究。实验发现,冷冻干燥样品测定的淀粉质量分数比高温干燥样品显著高出38.43%,酸水解方式比酶水解显著高出6.51%。还原糖测定方法中,DNS1和DNS2测定方法分别比斐林试剂滴定法显著高出29.67%和9.47%,DNS1比DNS2测定方法显著高出20.04%。不同水解-还原糖测定方法纯淀粉回收率和加标淀粉回收率均处于95%~105%之间,变异系数均小于2%,准确度和精确度符合质控规范。综合分析表明,冷冻干燥酶水解DNS1法测定甘薯淀粉含量具有最高的准确性和精确性,冷冻干燥酸水解DNS2法则具有最佳的实用性和方便性。

酶解胶原蛋白的多肽的制备与分析

以牛碱皮边角废料为原料，用两步酶解法提取胶原蛋白多肽，对影响酶水解过程的各个因素进行了分析；通过对水解产物分子量分布和等电点等指标的测定，发现分子量呈不连续分布，主要集中在某些分子量处，分子量的分布主要与水解方式和所用酶的种类有关。

The Dependence of the Dissociation Rate of Methane-SDS Hydrate below Ice Point on Its Manners of Forming and Processing

The dissociation rates of methane hydrates formed with and without the presence of sodium dodecyl sulfate （methane-SDS hydrates）, were measured under atmospheric pressure and temperatures below ice point to investigate the influence of the hydrate production conditions and manners upon its dissociation kinetic behavior. The experimental results demonstrated that the dissociation rate of methane hydrate below ice point is strongly dependent on the manners of hydrate formation and processing. The dissociation rate of hydrate formed quiescently was lower than that of hydrate formed with stirring; the dissociation rate of hydrate formed at lower pressure was higher than that of hydrate formed at higher oressure; the comoaction of hydrate after its formation lowered its stability, i.e., increased＇its dissociation rate.The stability of hydrate could beincreased by prolonging the time period for which hydrate was held at formation temperature and pressure before it was cooled down, or by prolonging the time period for which hydrate was held at dissociation temperature and formation pressure before it was depressurized to atmospheric pressure. It was found that the dissociation rate of methane hydrate varied with the temperature （ranging from 245.2 to 272.2 K） anomalously as reported on the dissociation of methane hydrate without the presence of surfactant as kinetic promoter. The dissociation rate at 268 K was found to be the lowest when the manners and conditions at which hydrates were formed and processed were fixed.