雁栖河流域水质的关键影响因素研究

针对雁栖河流域水质变差、富营养化风险增加等问题,通过对流域水质的连续监测,确定了影响流域水质的控制指标是TN和TP.在水质监测的基础上分析了流域水质的时空分布规律,并对流域污染负荷进行了调查和估算,在此基础上采用MIKE21建立平面二维水动力水质模型,对雁栖湖水质变化规律进行了模拟.研究表明,影响流域水质的关键因素是渔...     

小鼠微RNA miR-21真核表达质粒的构建及其在小鼠肾小球系膜细胞中的表达

目的构建小鼠微RNA miR-21真核表达质粒,并在小鼠肾小球系膜细胞中表达。方法人工合成小鼠miR-21基因序列,构建miR-21真核表达质粒pGenesil-miR-21。使用脂质体Lipofectamine2000转染小鼠肾小球系膜细胞后,G418筛选,获得稳定转染克隆,提取总RNA,通过实时荧光定量RT-PCR技术检测miR-21的表达。结果经酶切鉴定和测序证实,合成的miR-21基因序列完全正确,并已成功克隆到真核表达质粒pGenesil-1上。重组真核表达质粒转染小鼠肾小球系膜细胞后,筛选出的阳性克隆可稳定高表达miR-21。结论已成功构建miR-21真核表达质粒,并在小鼠肾小球系膜细胞中高效表达,为进一步探讨miR-21的生物学功能奠定了基础。     

北京新建筑地域性表达倾向

梳理了北京2000年以后建成的若干新建筑,依据地域性表达的程度和方式总结出3种较明显的倾向;通过对3种倾向的分析与归纳,反思了北京新建筑中地域性缺位问题,探讨了地域性表达的解决办法。     

C21甾苷提取方法的研究

为建立萝摩科植物及相应的保健产品中C21甾苷的定量方法，本文首先进行各咱提取方法的探讨。将用于强心苷薄层层析量显色的2-去氧糖反应进行了改进，作为进行各种提取方法C21甾苷相对含量比较的方法。根据C21甾苷的结构，选用了11种萃取剂进行了提取实验，并探讨了原料粉碎度、提取时间等其它条件对提取效果的影响，最终确定了C21甾苷的提取方法。     

The p53-, Bax- and p21-dependent inhibition of colon cancer cell growth by 5-hydroxy polymethoxyflavones

Scope: Previously, we reported that 5‐hydroxy polymethoxyflavones (5OH‐PMFs) isolated from orange, namely 5‐hydroxy‐6,7,8,3′,4′‐pentamethoxyflavone, 5‐hydroxy‐3,6,7,8,3′,4′‐hexamethoxyflavone (5HHMF) and 5‐hydroxy‐6,7,8,4′‐tetramethoxyflavone (5HTMF), potently induced apoptosis and cell‐cycle arrest in multiple human colon cancer cells. Herein, using isogenic variants of HCT116 human colon cancer cells, we investigated the effects of p53, Bax and p21 on the apoptosis and cell‐cycle arrest induced by different 5OH‐PMFs. Methods and results: Annexin V/PI co‐staining assay demonstrated that 5HHMF and 5HTMF significantly induced apoptosis in HCT116 (p53^+/+) cells but not in HCT116 (p53^?/?) cells. Furthermore, 5HHMF and 5HTMF significantly induced apoptosis in HCT116 (Bax^+/?) cells, whereas their pro‐apoptotic effects on HCT116 (Bax^?/?) cells were marginal. All three 5OH‐PMFs increased G0/G1 cell population of HCT116 (p53^+/+) cells, and these effects were abolished in HCT116 (p53^?/?) and HCT116 (p21^?/?) cells. Immunoblotting analysis showed that 5HHMF and 5HTMF increased the levels of cleaved caspase‐3, cleaved PARP in both HCT116 (p53^+/+) and HCT116 (Bax^+/?) cells and these effects were much weaker in HCT116 (p53^?/?) and HCT116 (Bax^?/?) cells. Conclusion: Our results demonstrated that 5OH‐PMFs, especially 5HHMF and 5HTMF, induce apoptosis and cell‐cycle arrest by p53‐, Bax‐ and p21‐dependent mechanism.     

水系调度对锡山区水环境改善效果分析

针对锡山区城市河网流动性差、水环境污染日益严重的问题,基于实测资料,利用MIKE11构建水动力水质耦合数学模型,综合考虑研究区内多种水利工程联合调度,以NH3-N为污染因子,模拟多种水系调度方案,分析水系调度对研究区水体流动性和水质的改善效果。结果显示,水系调度可提高研究区河道的流动性,加快水体更换;科学合理的水系调度方案可大幅降低研究区大部分考核断面的氨氮浓度,使水质达到Ⅳ类甚至更优,有效改善研究区水环境状况。     

MIKE SHE分布式水文模型在广东省中小河流洪水预报中的应用展望

中小河流急需提高洪水预报的有效性与及时性。 MIKE SHE是基于物理过程的分布式水文模型,具有高度灵活性、操作简单、应用范围广泛等特点。该文在分析中小河流洪水预报研究现状的基础上,提出MIKE SHE在广东省中小河流洪水预警预报中的应用展望。     

运用SW6进行双管板换热器管板的计算

由于ＳＷ６－９３（ＳＷ６－１９９８）软件包没有双管板换热器管板的计算模块，因此在设计计算时，我们将双管板换热器分成几个单管板换热器进行计算。几年来设计了数十台固定双管板换热器（卧式、立式）和Ｕ形管双管板换热器，下面介绍分解模式。     

Agglomeration and relocation: Manufacturing plant relocation in Korea

This study investigates the magnitude of localization economies by analysing the relocation pattern of Korean establishments in the manufacturing sector. Relocation of establishments is identified by their move across the border of wards, counties, or cities and distinguished between beyond and within their workers' commuting distance. It seems that relocation beyond commuting distance costs more than that within commuting distance since the former includes additional costs related with searching for, hiring, and training new workers. Key findings of this paper show that external benefits from agglomeration are large enough to be recognized by manufacturers through relocation beyond the border of their workers' commuting area. When the own industry's share of employment in all manufacturing industries becomes doubled through relocation, the probability for establishments to relocate over a long distance across the boundary of their workers' commuting area rises by 17 per cent. The results for sub‐samples divided by the age of establishments show that older establishments are more likely to relocate over a long distance to an area with disproportionate presence of establishments in the same industry. These results seem to fit product life cycle theory by Duranton and Puga. As the production process of the product becomes standardized, the firms producing that product tend to relocate to the specialized area where they can reduce the production costs by increasing dependence on the existing intermediate input suppliers, who are more likely to appear in a more specialized area.