Chemical Modification of Tryptophan Residues in Pullulanase

Tryptophan（Trp）residues in pullulanase have been chemically modified with N-bromossuccinimide（NBS）. The results of ultraviolet spectra indicated that there are 18 Trp residues in pullulanase and nine of them are located on the surface of the enzyme. Three of these Trp residues are none-essential residues which showed the fastest reaction speed by Zhou＇s plot. Two of the seven relative faster reacting residues are essential for the activity of the enzyme. The other eight are none-reactive residues with lowest reaction speed.     

Apoptotic Effects of Hypocrellin A on HeLa Cells

IntroductionApoptosis plays an important role in multiple phy-siological and pathological processes, such as the em-bryonic maturation of the immune system, neurologicaldegeneration and so on. Because cervical cancer is amajor cause of death among women i…     

具有自抗炎功能的胶原基海绵伤口敷料

将聚乙烯吡咯烷酮(PVP)在高温高压及KOH溶液中部分开环,得到具有羧基的ORPVP(开环率4%),再将其与胶原蛋白复合并交联制备得到具有自抗炎功能的海绵敷料.研究结果显示,该海绵材料具有均一的多孔结构,可在20s内快速吸水并接近溶胀平衡,保水率达35%;具有良好的自抗炎作用,可将由脂多糖引起的NO炎症因子降低57.1%;能有效促进NIH-3T3细胞增殖,有望在临床伤口修复治疗中得以应用.     

铈对液态共晶Fe—C合金粘度的影响

利用液态高温回转振荡粘度仪分别对共晶Fe-C合金和Fe-C-Ce合金(铈含量分别为0.08%,0.21%,0.59%)的粘度进行了研究.结果表明,在熔点以上至1420℃的范围内,共晶Fe-C合金的粘度在8.30～5.50mPa@s之间变化,而在熔点附近合金粘度的异常现象与液体合金中石墨的形成有关;铈含量大于0.21%明显降低了共晶Fe-C合金的粘度,分析表明,粘度的降低与液态合金自由体积的增加有关.Fe-C-Ce合金的粘度在1340～1370℃范围内出现反常变化,高温差示扫描量热(DSC)实验发现几乎在同样的温度范围存在异常峰位,分析表明这与液体合金内部的Ce-C化合物原子团簇有关.     

Two New Dammarane Glycosides from the Acid Hydrolysis Product of Panax Notoginseng

In our continuing research works on Panax notoginseng (Burk.) F. H. Chen, a famous traditional Chinese herb medicine1, two new dammarane glycosides named notoginsenosides T1 (1) and T2 (2) were isolated from the mild acid hydrolysis products of the root saponins. We report herein the structure elucidation of these two novel glycosides.Notoginsenosides T1(1) was obtained as white solid, [(] = +14.49 (0.50, MeOH). Its negative mode HR-FAB-MS spectrum showing the quasimolecular ion peak a…     

Generation of Sub-2 Cycle Optical Pulses with a Differentially Pumped Hollow Fiber

We report the generation of optical pulses with an energy of 0. 55 m^3 and duration of 1.6-cycle （4.4 fs） at repetition rate of 1 kHz using a differentially pumped hollow fiber and chirped mirrors. Compared to the statically gasfilled scheme, the differentially pumping hollow fiber is demonstrated to support more energy output with higher transmission efficiency, and to increase the spectral broadening due to a reduction of ionization defocusing in plasma at the fiber entrance. The differentially pumping technique is proved to be an effective way to obtain optical pulses with mono-cycle and higher energy.     

Complex locally uniform rotundity of Musielak-Orlicz spaces

The concepts of complex locally uniform rotundity and complex locally uniformly rotund point are introduced. The sufficient and necessary conditions of them are given in complex MusielakOrlicz spaces.     

基于磁性Fe_3O_4/Ag的表面增强拉曼光谱检测农药丙线磷

以共沉淀法合成Fe3O4纳米颗粒,再通过柠檬酸三钠还原AgNO3制备Fe3O4/Ag磁性复合材料。Fe3O4/Ag能够与溶液中的丙线磷形成吸附,通过磁性收集达到萃取富集的效果。测定吸附于Fe3O4/Ag表面的痕量丙线磷所产生的表面增强拉曼光谱(SERS),其检测过程的拉曼增强因子为1.48×105,极大地提高了检测灵敏度,建立了磁性Fe3O4/Ag萃取富集与SERS分析农药丙线磷的方法。采用紫外可见吸收光谱、能谱及透射电子显微镜对制备的材料进行了分析及形貌与结构的表征。并对丙线磷模型分子进行结构优化的密度泛函理论计算,得到了理论拉曼光谱和谱峰归属,以用于丙线磷的判断。结果表明,SERS峰强在富集15min后基本趋于稳定,其丙线磷浓度低至2×10-8 mol·L-1仍有明显响应,可以满足丙线磷农残检测的要求。其方法可推广至含硫有机磷农药残留的分析。     

象山港沉积物对重金属Fe和Mn的吸附特征

对象山港不同站点的沉积物对重金属铁、锰的吸附特征进行了研究,考察了阳离子交换量、有机质含量对铁、锰的吸附能力的影响。吸附动力学实验表明,沉积物对铜和锌的吸附量随着铁、锰的初始含量增加而增大,但分别都在40 min和30 min左右达到吸附平衡;热力学实验结果表明,不同沉积物对铁、锰的热力学吸附过程符合Freundlich等温方程,各站点沉积物对铁的吸附能力由强到弱依次是S02,S25,S17,S10,S12,D03,D08,各站点沉积物对锰的吸附能力由强到弱依次是S02,S25,S17,S12,S10,D03,D08;影响因素实验表明,有机质的含量是影响沉积物对重金属铁吸附能力的主要影响因素之一,而沉积物对锰的吸附能力与阳离子交换量存在一定的关联性,有机质的含量几乎不影响沉积物对锰的吸附能力。因此,沉积物对重金属铁、锰的吸附系数K并不与其中单个理化性质有明显的相关性,这说明沉积物对铁、锰的吸附强度受多种沉积物理化性质控制。     

装备维修器材生产路径双目标问题优化决策方法研究

在装备维修器材供应保障中,针对精确保障背景下部队用户对器材保障精度的要求,构建了最小化总成本和最大化订单精准执行率的双目标优化决策模型。在ε-约束法框架内,开发可生成近似Pareto前沿的两阶迭代启发式算法,并采用模糊逻辑决策法选择符合决策者偏好的折中最优解。随机实例测试结果表明所提出的模型和算法可以很好地应用在双目标优化问题的研究中,并在求解不同规模实例时表现出优异的性能。