连翘酯甙分离提取及抑制弹性蛋白酶活性研究

弹性蛋白酶是一种水解酶 ,具有降解胶原蛋白、弹性蛋白等多种蛋白质的能力。在体内 ,当弹性蛋白酶与天然抑制剂的平衡失衡后 ,酶活力增加 ,这是诱发包括肺气肿在内的多种疾病的病因之一[1] 。因此 ,寻找合适的弹性蛋白酶抑制剂 ,增强机体抑制弹性蛋白酶的能力 ,进而恢复体内弹性蛋白酶与天然抑制剂的平衡 ,是研究治疗肺气肿疾病药物的一条有效途径。据报道[2 ] 连翘水提液具有抑制弹性蛋白酶的作用 ,但尚未见进一步研究报道。我们对连翘中的主要有效成分连翘酯甙进行了分离提取 ,并初步研究了连翘酯甙对猪胰弹性蛋白酶 (ＰＰＥ)的抑制作用。…     

冷轧谐波齿輪成形工艺及質量分析

本文介绍了作者对冷轧谐波齿轮成形工艺的研究成果。文中给出了合理的轧制条件受工艺参数,对轧制齿轮的质量也进行了较为详细的分析。     

Surface Modification of Montmorillonites by Chlorosilanes

Montmorillonite was modified by chlorosilane derivatives (trimethylchlorosilane and tert-butyldimethylchlorosilane)based on the reaction between OH group and chlorosilane,Fourier-transformed infrared spectra(FTIR)confirmed that chlorosilanes did react with the OH groups of montmorillonite.The effect of reaction time and dispersing agents on the intercalation was studied by wide angle X-ray diffraction(WAXD) method.Further experiments proved that there is no reactive OH group on the surface of layers in the interlayer galleries of montmorillonite.The cation exchange capacity(CEC) of montmorillonites was measured.showing that after modification by chlorosilane derivatives,CEC values drastically decreased.The dispersibility measurements of montmorillonites were conducted.which showed that the dispersibility of modified montmorillonites both in H2O and toluene wer improved due to the decrease of attractions of particles and layers.     

十二烷基硫酸钠诱导Rhodobacter azotoformans外周捕光复合体LH2 B800细菌叶绿素特异性解离

采用吸收光谱法研究了十二烷基硫酸钠(SDS)诱导Rhodobacter azotoformans外周捕光复合体LH2 细菌叶绿素(bacteriochlorophylls, BChls)的解离行为和规律. 结果表明: 室温下, 在10 mmol•L^－1 Tris-HCl (pH 8.0)缓冲液中, 低浓度SDS只诱导LH2中B800 细菌叶绿素解离生成游离BChls, 而B850不受影响; 当浓度达到0.08% (w/V) 时, 能特异性地诱导B800缺失, 其缺失过程和游离BChls的生成过程均符合单指数模型, 且二者的速率常数近似相等. 高浓度SDS能同时诱导B800和B850解离生成游离BChls, 其中B800可发生缺失, 而B850则不完全解离, 解离过程均符合单指数模型; B800对SDS更敏感, 其解离速率常数约是B850的4倍, 游离BChls生成速率常数明显低于B800解离速率常数, 而与B850解离速率常数相接近.