序列相关Setup单机调度的最小化最大拖期分枝定界算法

研究了具有序列相关Setup带交货期的单机调度NP问题,优化目标是最小化最大拖期.通过松弛子路径连通约束,提出了基于AP算法的下界方法.在算法下界的基础上,基于下界解建立了以改进Karp-Steel补偿启发式方法构成的上界构造方法.发现了反映问题特性的两条优势规则.最后依托Ragatz提出的分枝定界算法框架,引入上界和下界方法,以及两条优势规则,形成了求解该问题的分枝定界枚举算法.通过计算实验证明了算法的有效性.     

材料热释放速率的试验分析

材料的热释放速率是决定火灾危害的关键因素.为系统了解热释放速率的性质以及与其他参数间的关系,从锥形量热计的耗氧原理出发,详细阐述了热释放速率的计算,利用锥形量热计研究了几种有代表性的材料分别在不同的辐射能量下的热释放速率.结果表明,热辐射能量与热释放速率成线性的变化规律,与点燃时间开方的倒数成线性关系.     

海藻酸钠微囊对蛋白质控制释放的分析

研究一种蛋白质类药物的控缓释系统的工艺条件及其体外释放行为;以牛血清白蛋白(BSA)为模型药物,海藻酸钠(Alg)为包埋材料制备微囊,研究不同的阳离子、不同BSA浓度时,测定微囊的形态、粒径和包埋率的影响,并对该微囊包埋前后的完整性和体外溶出速度进行了测定;用Ba2 制备的微囊成型稳定,粒径均一,具有良好的包埋率;发现微囊在制备过程中,BSA没有受到破坏,BSA蛋白分子保持了结构的完整性;用海藻酸钠作为包埋材料对蛋白有一定的缓释效果,突释效应也并不十分明显.     

尿素-壳聚糖微胶囊囊芯释放速率的研究

研究了操作条件对缓释型肥料——尿素-壳聚糖微胶囊囊芯释放速率的影响,并研究了微胶囊在中性(水)、弱酸、弱碱条件下的释放速率.实验表明,胶囊中囊芯的释放速率主要由芯壁比决定,囊壁的壳聚糖质量分数以3%为宜.     

庆大霉素-聚酸酐缓释制剂的制备及释药特性

以聚（二聚酸－癸二酸）共取物[P(DA-SA),wDA;WSA=50:50]为药物缓释材料,庆大霉素为模型药物,采用热熔法制备庆大霉素－聚酸酐缓释药棒,初步的制剂稳定性研究表明,在室温干燥条件下,该缓释药棒具有良好的制剂稳定性,体外释药结果表明,在37度时质量分数为0．9％的生理盐水体系中,该缓释药棒的体外释药时间为25d,释药动力学符合一级动力学方程,其体外释药程为：Y＝9．1826＋6．690lt-0.1272t2,R2=0.9874,上述结果表明庆大霉素－聚酸酐缓释药棒是一类具有明显缓释作用的释药体系。     

几种释放因素对紫杉醇合成与释放的影响

比较研究了几种释放因素对红豆杉细胞生长和紫杉醇合成与释放的影响,结果表明,在中国红豆杉细胞悬浮培养过程中,在细胞生长对数期（14d)加入φ＝5％二甲亚砜及0．2mol/L甘露醇,能显著提高紫杉醇的合成及释放,紫杉醇总产量达到16mg/L,在细胞生长在对数期（14d)加入0．04mol/L氯化钠时,紫杉醇总产量达到7．3mg/L,在细胞生长对数期（14d）加入2mg/L硫酸铈铵时,紫杉醇总产量达到24mg/L。     

红枣乳酸菌饮料的研制

以红枣汁和凝固型酸奶为主要原料 ,枣汁先与牛乳混合发酵后 ,再稀释调配成乳酸菌饮料 ,加工中选择适当的稳定剂使饮料中的乳蛋白粒子均匀分散 ,防止凝集沉淀     

Effects of myocardial ischemia and reperfusion on mitochondrial function and susceptibility to oxidative stress

We investigated the effects of ischemia duration on the functional response of mitochondria to reperfusion and its relationship with changes in mitochondrial susceptibility to oxidative stress. Mitochondria were isolated from hearts perfused by the Langendorff technique immediately after different periods of global ischemia or reperfusion following such ischemia periods. Rates of O₂ consumption and H₂O₂ release with complex I- and complex II-linked substrates, lipid peroxidation, overall antioxidant capacity, capacity to remove H₂O₂, and susceptibility to oxidative stress were determined. The effects of ischemia on some parameters were time dependent so that the changes were greater after 45 than after 20 min of ischemia, or were significantly different to the nonischemic control only after 45 min of ischemia. Thus, succinate-supported state 3 respiration exhibited a significant decrease after 20 min of ischemia and a greater decrease after 45 min, while pyruvate malate-supported respiration showed a significant decrease only after 45 min of ischemia, indicating an ischemia-induced early inhibition of complex II and a late inhibition of complex I. Furthermore, both succinate and pyruvate malate-supported H₂O₂ release showed significant increases only after 45 min of ischemia. Similarly, whole antioxidant capacity significantly increased and susceptibility to oxidants significantly decreased after 45 min of ischemia. Such changes were likely due to the accumulation of reducing equivalents, which are able to remove peroxides and maintain thiols in a reduced state. This condition, which protects mitochondria against oxidants, increases mitochondrial production of oxyradicals and oxidative damage during reperfusion. This could explain the smaller functional recovery of the tissue and the further decline of the mitochondrial function after reperfusion following the longer period of oxygen deprivation. Received 18 May 2001; received after revision 17 July 2001; accepted 24 July 2001     

广西巴马小型猪促生长激素释放激素成熟肽的克隆及序列分析

目的扩增广西巴马小型猪促生长激素释放激素(GHRH),分析其序列结构特点。方法以广西巴马小型猪基因组DNA为模板,用特异性引物扩增GHRH外显子3,再用引物延伸悬挂PCR法扩增GHRH成熟肽,纯化后,连接、转化到大肠杆菌,筛选阳性克隆,测序。结果经测序证实广西巴马小型猪GHRH外显子3及其成熟肽的基因序列与相关文献报道一致。克隆得到的广西巴马小型猪GHRH序列全长为132 bp,其中外显子3基因序列长105bp。同源性比较发现,广西巴马小型猪GHRH外显子3基因序列与GenBank(NCBI)中报到的猪GHRH外显子3相比,同源性为97.14%,有3处发生碱基变化。结论本实验成功克隆了广西巴马小型猪GHRH成熟肽序列。     

固体防垢块中的HEDP粉末的制备

用固体防垢块防止油井结垢,有效期长。为筛选制作这种固体块所需的材料,评价了7种膦酸盐防垢剂,发现羟基乙叉二瞵酸(HEDP)对碳酸钙垢具有较高的防止能力,且热稳定性好。将HEDP防垢剂水溶液由一定浓度的NaOH中和后,经烘干、粉碎,可制得水溶性好、防垢率高的HEDP钠盐粉末;另一种方法是在HEDP水溶液中按n(Ca(OH)₂)/n(HEDP)=1.75的比例加入Ca(OH)₂,经过滤、烘干后,可得到能在水中缓慢溶解的HEDP粉末,其主要成分是Ca₂HEDP。上述两种HEDP粉末同聚乙烯混炼,可制备出固体防垢块。