PM2.5暴露对肺AQP1表达的影响研究

为研究肺水通道蛋白1（AQP1）在PM_2.5暴露引起肺损伤中的作用,本文首先在细胞水平上检测了PM_2.5暴露对肺上皮细胞A549的细胞存活率、细胞AQP1的mRNA和蛋白表达变化,以及AQP1在细胞内的表达定位的影响.另外,将10只雄性SD大鼠随机分为2组：对照组和PM _2.5染毒组（1.5 mg·kg^-1体重）,每组5只,采用气管滴注法染毒,每隔1 d染毒1次,共2周,制备PM_2.5暴露大鼠模型,进一步观察PM_2.5暴露对大鼠肺AQP1表达及肺组织损伤的影响情况.结果显示,PM_2.5暴露可引起肺上皮细胞A549形态异常和存活率降低.PM_2.5暴露后的24 h内A549细胞的AQP1 mRNA及蛋白相对表达水平先升高,并在暴露后的12 h内达到最高水平,然后有所下降;免疫荧光结果也证实AQP1蛋白在PM_2.5暴露后表达水平升高,并呈现从细胞质向细胞膜定位的过程;用PM_2.5暴露处理SD大鼠肺组织中AQP1表达亦显著增加,并且肺组织出现肺泡隔增厚,并有广泛的水肿充血及炎症细胞浸润.总之,PM_2.5暴露可诱导A549细胞及大鼠肺组织内AQP1的表达升高,可能参与PM_2.5暴露引起的肺病理性损伤过程.     

冬季北京城区PM2.5诱导人肺上皮细胞系A549中多环芳烃受体(AhR)通路的激活

使用冬季北京市城区的细颗粒物（PM_2.5）评估其对人肺上皮细胞系A549中多环芳烃受体（AhR）通路的激活作用.利用CCK-8法检测细胞暴露PM_2.5后的存活率,选取50%抑制浓度（IC₅₀）作为细胞暴露剂量,采用Western blot和免疫荧光检测PM_2.5暴露诱导AhR定位变化,采用荧光定量PCR和Western blot检测AhR的靶基因CYP1A1的转录和翻译水平改变,应用双荧光素酶报告基因法测定AhR与靶基因结合位点（XRE）的活性,利用酶标仪测定CYP1A1的酶活性改变.结果显示,随着暴露时间的增加,AhR逐渐从细胞质易位至细胞核;CYP1A1 mRNA和蛋白质的表达水平也呈时间依赖性显著增加;AhR与XRE结合活性的增加表明了PM_2.5诱导CYP1A1增加的调节机制;最后引起细胞内CYP1A1酶活性显著增加.研究表明,来自冬季北京城区的PM_2.5样品可激活A549细胞的AhR通路,提示AhR介导的信号途径可能与PM_2.5的暴露毒性有关.     

Modeling the probability of freeway lane-changing collision occurrence considering intervehicle interaction

Objective: To better capture the relationships between lane-changing collisions and explanatory variables, a microscopic model is developed for freeway lane-changing collisions based on the interactions between lane-changing vehicles.

Methods: The model applies an intervehicle interaction structure to account for the occurrence mechanism of lane-changing collisions. The occurrence mechanism can be described as the failure of a vehicle driver of an adjacent lane in avoiding the lane-changing vehicle, which disturbs the smooth movement of the adjacent lane vehicle and requires the driver's brake action to avoid an angle collision. This model is examined using data collected from freeways in Washington State during 2010 to 2011 and validated using lane-changing collision data for the SR 520 freeway.

Results: The findings of this study show that generalized truck percentage has a significant decreasing effect on lane-changing collision risk, whereas average spacing and several roadway characteristics have significant increasing effects. The frequency of slight collisions during peak hours is higher than that during off-peak hours. Young female drivers are more likely to be involved in collisions during lane-changing than young male drivers, but the result for senior drivers is opposite, with older male drivers having a higher probability of lane-changing collisions than female drivers in the same age group.

Conclusion: The process of lane-changing collisions is a complicated maneuver. Truck percentage, average spacing, and good roadway characteristics, such as straight and level segment, in the target lane have a significant effect on the occurrence of lane-changing collisions. Age and gender are also 2 important factors contributing to the relationship between lane-changing collisions and explanatory variables.     

探究性教学在大学语文课程中的运用——以讲授苏轼《水调歌头》一课为例

《大学语文》作为高职高专的一门公共基础课,因其丰富的人文内蕴、情感价值和审美趣味而承担了进一步提高大学生人文素质、增进文化修养的功能,从而培养大学生具有深厚人文精神的理想人格。在《大学语文》教学活动中开展探究性教学,既是教育改革全面实施素质教育的客观要求,也是大学生自我提升的内在需要。以讲授苏轼的《水调歌头·明月几时有》一课为例,阐述如何在高职高专《大学语文》课程的教学活动中引导和组织学生开展探究性教学。     

双酚芴的清洁生产工艺

根据清洁生产的理论与思维模式，对生产双酚芴的传统工艺进行了改进，以强酸性阳离子交换树脂代替传统的催化剂催化合成双酚芴，以沸水代替甲醇水溶液洗涤反应混合物，产生的废液经液液萃取和蒸馏处理，使苯酚等有效组分被回收利用，解决了废液的排放问题，基本实现了双酚芴产品的清洁生产。采用清洁生产工艺生产双酚芴，每生产1t产品可从废液中回收1．6t苯酚，按30t／a计算，可节约资金约43．2万元/a。与传统工艺相比，双酚芴的清洁生产工艺在经济效益和环境效益方面有明显优势。     

Performance of the supported copper oxide catalysts for the catalytic incineration of aromatic hydrocarbons

A fixed bed reactor was used to assess the catalytic incineration of toluene by various transition-metal oxide species supported on gamma-Al(2)O(3). CuO/gamma-Al(2)O(3) was found to be the most active of seven catalysts investigated. The CuO species, with a Cu content of 5% (wt), was hence used with four different supports (CeO(2), gamma-Al(2)O(3), TiO(2) and V(2)O(5)) in order to define the optimal combination. Results of the catalytic incineration of toluene, X-ray diffraction (XRD) analysis, oxygen-temperature programmed desorption (O(2)-TPD), toluene-temperature programmed desorption (toluene-TPD) and hydrogen-temperature programmed reduction (H(2)-TPR) showed that CuO/CeO(2) was the most active catalyst, followed by CuO/gamma-Al(2)O(3). The activity of CuO/CeO(2) with respect to the VOC molecule was observed to follow this sequence: toluen>p-xylene>benzene. The addition of water vapor or CO(2) significantly inhibited the activity of the CuO/CeO(2) and CuO/gamma-Al(2)O(3) catalysts. The inhibiting effect of both was reversible for CuO/gamma-Al(2)O(3). For CuO/CeO(2), the inhibiting effect of CO(2) was reversible and even insignificant at a higher temperature (220 degrees C), but the effect of H(2)O vapor was somewhat irreversible at lower incineration temperatures (220 degrees C). For complete oxidation of toluene, the required reaction temperature increased with gas hourly space velocity (GHSV) and toluene inlet concentration.     

A historical perspective of river basin management in the Pearl River Delta of China

Three innovations in water and soil conservancy technology in the Pearl River Delta of South China, i.e., dike building, land reclamation, and dike-pond systems, were examined from a historical perspective. They were found to best reflect local farmers' efforts to cope with the challenges of various water disasters and to build a harmonious relationship with the changed environment. These technologies were critical to the agricultural success and sustainability over the past 2000 years, and reflected local farmers' wisdom in balancing land use and environmental conservation. Imprudent use of a new agricultural technology could damage the environment, and could disturb the human-environment relationship, as evidenced by the more frequent flooding that followed inappropriate dike building and premature reclamation. It is suggested that as the urbanization and industrialization process in the delta region continues, the kind of thinking that made the water and soil conservancy sustainable needs to be incorporated into the design of similar technologies for water use and river basin management today.     

绿色壁垒的法律分析

面对我国国际贸易深受国外绿色壁垒影响的现状,我国应以国际规则坚决抵制贸易保护主义,制定绿色产品及其包装发展鼓励条例,并不断完善环境管理和绿色保障法律制度。