木犀草素通过抑制p65 NF-κB、促进p85 PI3K调节微血管内皮细胞VCAM-1表达

通过抑制微血管内皮细胞血管细胞黏附分子(VCAM)-1的表达,木犀草素可阻遏中性粒细胞与微血管内皮细胞的黏附,起到抗炎作用.木犀草素调节VCAM-1表达与三条信号通路有关:丝裂原活化蛋白激酶(MAPK)、核因子kappa B(NF-κB)/IκB和磷脂酰肌醇3激酶(PI3K)/Akt通路.其中,MAPK和NF-κB/IκB通路参与VCAM-1正向调节,PI3K/Akt通路参与VCAM-1负向调节.本文研究了木犀草素对微血管内皮细胞该三条通路中的关键蛋白p38 MAPK、p65 NF-κB、p85 PI3K磷酸化.结果表明:木犀草素在反应的30 s和1 min促进p38 MAPK磷酸化,在30 s、1 min和5 min促进p85 PI3K磷酸化,而在30 s、1 min、5 min和30 min抑制p65 NF-κB磷酸化.阻抑p38 MAPK通路导致VCAM-1表达下调,而p38 MAPK抑制剂SB203580可通过抑制p38 MAPK磷酸化也下调VCAM-1,提示木犀草素对微血管内皮细胞VCAM-1的调节作用独立于p38 MAPK磷酸化.由此可知,木犀草素通过抑制p65 NF-κB磷酸化或促进p85 PI3K磷酸化调节微血管内皮细胞VCAM-1表达.本文为木犀草素抗炎作用的分子机制研究提供了新的线索.

基于T-S模糊故障树的钻爆法施工隧道坍塌可能性评价

针对钻爆法施工隧道施工过程复杂、风险影响因素多、坍塌事故率高,且传统故障树分析方法的应用受概率和精确与或关系的限制以及事件状态只考虑'二态性'的问题,为降低施工风险和预防提供决策依据,提出一种基于T-S模糊故障树的钻爆法施工隧道坍塌可能性评价方法。该方法将模糊数和T-S模糊门引入到故障树分析中,用T-S模糊门代替传统逻辑门描述事件之间的联系,体现出系统故障机制和事件联系的模糊性,同时降低了故障树的建立难度。用模糊数描述各底事件的故障概率和故障程度,克服了传统故障树过度依赖精确故障概率以及不能考虑事件故障状态对系统影响的问题,该方法不仅实现了用底事件的先验模糊可能性和施工中实际故障状态两种不同的方式计算隧道坍塌可能性,而且可以根据底事件重要度分析结果指导风险控制工作。对两个工程实例进行了分析,应用结果表明,所提出的方法相比传统故障树更加符合工程实际,能够更加科学、合理地评价隧道坍塌的可能性以及确定关键致险因子,可作为隧道施工安全风险分析和管理的决策工具。

DATA PROCESSING FOR GPS PRECISE POINT POSITIONING

In the data processing of the precise point positioning (PPP), the un-difference method is commonly used. However, GPS measurements can be differenced with satellites or different observation epochs. In theory,these differencing approaches should be mathematically equivalent. The positioning performance of different PPP data models, including un-difference (UD), satellite difference (SD), time difference (TD) and time-satellite difference (TSD), is examined using the 24 h GPS observation. The positioning accuracy, convergence of ambiguity, and tropspheric delay estimation with these four models are compared with each other.

MULTI-FUNCTION VEHICLE NAVIGATION AND MONITORING SYSTEM IN URBAN AREAS

A vehicle navigation and monitoring system integrated by a high precision navigation system and a vehicle black box is studied to satisfy the demand for the intelligent transportation system (ITS). Firstly, the architecture of the system is proposed. Then the integration scheme of global positioning system/dead reckoning/bluetooth beacon/map matching (GPS/DR/BB/MM) with the hluetooth assistant positioning technology, and the algorithm of the Kalman filter for the integrated GPS/DR are investigated. Finally many field trials for principle prototypes are made. Experimental results show that the proposed integrated navigation algorithm is effective and feasible, and the function of the vehicle black-box is realized.

Co-transformation of HMs-PAHs in rhizosphere soils and adaptive responses of rhizobacteria during whole growth period of rice(Oryza sativa L.)

This study investigated the transformations of heavy metals(HMs) and polycyclic aromatic hydrocarbons(PAHs) in rhizosphere soils and adaptive responses of rhizobacterial community under the real field conditions during four growth stages(e.g., greening, tillering, heading, and maturity) of early rice(Zhongjiazao 17) and late rice(Zhongyou 9918) in Jiangshe village(JSV) and Yangji village(YJV). Results showed that rhizosphere soils of YJV were mildly polluted by Cd and PAHs compared to that of JSV. The relative abundance of bioavailable Cd(bio-Cd) and bioavailable As(bio-As) in rhizosphere soil increased before the heading stage but decreased at the subsequent growth stage, but the content of ΣPAHs in rhizosphere soil decreased gradually during whole growth period. The dominant rhizobacteria genera at YJV(e.g., Bacillus, Massilia, Sphingomonas, and Geobacter) increased at an abundance level from the tillering to heading stage. Rhizobacteria interacted with the above co-pollutant more intensely at the tillering and heading stage, where genes involved in HM-resistance and PAH-degradation appeared to have a significant enhancement. The contents of bioCd and bio-As in rhizosphere soil of early rice were higher than that of late rice at each growth stage, especially at the heading stage. Bio-Cd, ΣPAHs, and organic matter were key factors influencing the community structure of rhizobacteria. Results of this study provide valuable insights about the interactions between HM-PAH co-pollutant and rhizobacterial community under real field conditions and thus develop in-situ rhizosphere remediation techniques for contaminated paddy fields.

偶遇

1潮街在朝阳北路的边上。潮街不是有多潮才迷惑了董二豆,是潮街的水太深了,一直淹没到董二豆的脖子里,让他室息了,魔幻了,才塑造出现在的董二豆来。董二豆看起来有四十七八岁的样子。秃顶,或者不能叫秃顶,而是叫秃偏——秃顶秃成是“地中海”式的较为普遍。董二豆的秃顶不是秃在正中心,秃偏了,偏在左边,整个头的左侧秃了,大约占整个头部的三分之一强。