响应面法优化花椒总多酚的吸附分离工艺

以花椒籽为原料,在单因素实验基础上,用响应面法优化花椒总多酚的大孔树脂吸附分离工艺,考察了pH值、吸附温度和吸附时间对总多酚提取率的影响,建立了数学模型,并对试验结果进行了显著性检验和方差分析.结果表明,在pH值6.0,70℃吸附90min后,总多酚提取率为3.867 2%,模型预测值为3.929 7%,组合实验结果比模型预测值小0.062 5%.     

一般预测模型的预测值y＊-优越性

评估一般预测模型y＊=X＊β＋ε＊预测值y＊的优越性,仿照估计值（β）的均值分散误差,引入预测值y＊的均值分散误差准则,并因此定义预测值的y＊-优越性.主要依据所给定义得出我们所定义的预测值y＊-优于经典预测值（P）0=X＊（β）口的条件.     

音教美学的现代重构

美学教育在现代的一个突出进展，是从音乐主观直觉切入，最终达到审美能力的提高。在美学现代性的理论前提下．从现代网络及音乐教育环境的现状观察的基础上，研究了审美发生的内容和形式，讨论了在现代音乐教育产业正在形成的背景上，审美如何实现其艺术性与生存两者兼顾。     

《类篇》异读字所反映的云、以合流演变规律

云母本为匣母之细音,最初与以母有别,到唐代时渐读为一类,沿及宋代皆变为零声母,本文主要通过《类篇》中19个云以异读字例分析其合流的演变规律.     

大行程升降舞台结构方案的二级模糊综合评判

提出了一种对大行程升降舞台进行结构方案选择的模糊综合评判法 .该方法在对不同结构形式进行全面性能分析的基础上 ,以模糊变量的定量描述为手段 ,将综合性能的优劣用量化指标反映出来 ,从而可以从众多的可行方案中选出最佳方案 .这种方法也为舞台机械和其它产品的选型提供了依据     

中英咨询业比较研究

分析比较了中英两国咨询业发展的历史、现状、咨询业人员的素质、政府对咨询业扶植的政策，从英国咨询业的特点，找出我国咨询业现存在的问题，提出了我国咨询业发展的对策。     

以科学手段保障运城电网安全

对电网事故情况下调度自动化系统所发挥的作用进行了分析，结合运城电网实际，讨论了实用化工作中存在的问题，并提出了改进建议。     

Hochschild公式的推广

Hochschild曾证明了如下公式:如果F是特征p的域,D是F的一个非零导子,a是F中的任一元素,则成立本文将这一公式推广到特征为p的交换环上,进一步推广到n个导子的更一般的情况。     

β-phenylethyl isothiocyanate-mediated apoptosis in hepatoma HepG2 cells

-Phenylethyl isothiocyanate (PEITC) is a promising chemoprotective compound that is routinely consumed in the diet as its glucosinolate precursor. Previous studies have shown that PEITC can inhibit phase I enzymes and induce phase II detoxification enzymes along with apoptosis in vitro. The detailed mechanisms involved in the apoptotic cascade, however, have not been elucidated. In the present study, we demonstrate that PEITC can induce apoptosis in hepatoma HepG2 cells in a concentration- and time-dependant manner as determined by TUNEL positive and SubG1 population analysis. Caspase-3-like activity and poly(ADP-ribosyl)polymerase cleavage increased during treatment with 20 µM PEITC; high concentrations, however, induced necrosis. Pre-treatment with Z-VAD-FMK and the caspase-3-specific inhibitor Ac-DEVD-CHO prevented PEITC-induced apoptosis, as determined by caspase-3-like activity and DNA fragmentation. Additional investigations also showed that at concentrations of 5-C10 µM PEITC, DNA synthesis was inhibited and G2/M phase cell cycle arrest occurred, correlating with an alteration in cyclin B1 and p34^cdc2 protein levels. Furthermore, we also demonstrate a concentration- and time-dependant burst of superoxide (O₂^-) in PEITC-treated cells. However, pre- and co-treatment with the free radical scavengers Trolox, ascorbate, mannitol, uric acid and the superoxide mimetic manganese (III) tetrakis (N-methyl-2-pyridyl) porphyrin failed to prevent PEITC-mediated apoptosis. Taken together, these results suggest that PEITC potently induces apoptosis and cell cycle arrest in HepG2 cells and that the generation of reactive oxygen species appears to be a secondary effect.Received 23 December 2002; accepted 22 April 2003     

太原市环境监测现状及发展对策探讨

现代化的环境监测是现代化环境管理的基础工作，是科学监督管理的重要手段。阐述了太原市环境监测的现状和存在的主要环境问题，并有针对性地在加强太原市环境监测能力建设和深化监测事业改革等方面提出了具体的对策和建议。