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951.

Fine particle matters (PM2.5) is a well-known risk factor for cardiovascular diseases. However, the underlying molecular mechanisms are largely unknown. Vascular hyper-reactivity plays an important roles in the pathogenesis of cardiovascular diseases. The present study was designed to investigate a hypothesis that PM2.5 up-regulated endothelin receptors in mesenteric artery and the potential underlying mechanisms. Rat mesenteric arteries were cultured with PM2.5. The artery contractile responses were recorded by a sensitive myograph. ETB and ETA receptor expressions of mRNA and protein were assessed by quantitative real-time PCR, Western blotting, and immunohistochemistry, respectively. Results showed that ETB receptor agonist, sarafotoxin 6c induced a negligible contraction in fresh artery segments, while ETA receptor agonist, ET-1 induced an obvious contraction. After organ culture, the contraction curve mediated by ETB and ETA receptors were shifted toward the left. PM2.5 1.0 μg/ml cultured for 16 h further enhanced ETB and ETA receptor-mediated contractile responses with a markedly increased maximal contraction. The organ culture enhanced ETB and ETA receptor mRNA and protein levels from fresh arteries, which were further increased by PM2.5. The U0126 (MEK/ERK1/2 inhibitor) and SB203580 (p38 inhibitor) significantly attenuated both organ cultured-induced and PM2.5-induced up-regulation of ETB receptor. U0126 also suppressed organ culture-increased and PM2.5-increased expressions of ETA receptor. SB203580 only suppressed PM2.5-induced enhanced expressions of ETA receptor In conclusion, airborne PM2.5 up-regulates ETB and ETA receptors of mesenteric artery via p38 MAPK and MEK/ERK1/2 MAPK pathways.

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952.
Environmental Science and Pollution Research - The mechanisms of abrupt seasonal temperature changes and warming (cooling) hiatuses remain unclear. Clarifying how they respond to various...  相似文献   
953.
Environmental Science and Pollution Research - A novel adsorbent derived from banyan aerial roots was prepared via modification and employed to aqueous gentian violet (GV) and rhodamine B (RhB)...  相似文献   
954.
Environmental Science and Pollution Research - Rapid separation and analysis of trace quinolones (fleroxacin (FLRX), enoxacin (EN), norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENRO), and...  相似文献   
955.
Environmental Science and Pollution Research - In this study, the feasibility of banana straw (BS) hydrolysate as carbon source and reutilizing the pretreated liquor (PL) of BS in the...  相似文献   
956.
旅游吸引力是目的地旅游发展的动力源泉,基于需求侧的旅游吸引力评价对于乡村旅游地的经营管理和市场营销具有重要的指导意义。以江西省为例,在乡村旅游地类型划分的基础上,构建了基于网络信息的乡村旅游地吸引力评价体系,同时采用空间自相关和核密度分析方法分析了乡村旅游地吸引力的空间分布格局,研究发现:(1)江西省乡村旅游地可以划分为生态观光类、休闲度假类、农事体验类、农业科技类、乡土文化类和特色村镇类六个大类和24个基本类型;(2)江西省乡村旅游地单体吸引力指数相差较大,不同类型乡村旅游地吸引力指数差别显著,生态观光类吸引力指数最高,农业科技类最低;(3)江西省乡村旅游地为旅游者带来了良好的游憩体验,旅游者整体满意度较高,但网络关注度与分享程度相对较低;(4)江西省乡村旅游地吸引力集聚特征显著,且主要集中在“南昌-九江-宜春”、“萍乡-宜春”、“上饶-景德镇”三大片区,各类型乡村旅游地吸引力集聚状况空间差异较大。基于研究结论,文章为江西乡村旅游吸引力的提升及未来乡村旅游的发展提出了针对性的意见与建议。  相似文献   
957.
采用氟、磷、钾化肥三因素通用旋转组合设计,通过计算机模拟寻优,建立了湘南砂岩红壤玉米-大豆立体栽培模式中玉米施肥量-产量、玉米施肥量-利润数学模型;优选出玉米产量和利润最高的各10套施肥方案;计算出玉米最高产量的施肥量为:尿素750kg/hm2,过磷酸钙1125kg/hm2,氯化钾332kg/hm2,N∶P2O5∶K2O=1∶0.39∶0.58;计算出玉米最佳经济效益施肥量为:尿素712.8kg/hm2,过磷酸钙1125kg/hm2,氯化钾285.2kg/hm2,N∶P2O5∶K2O=1∶0.41∶0.52.玉米与大豆的产量间以及两者的利润间均呈极显著正相关.  相似文献   
958.
In recent years the issue of the municipal waste in Poland has become increasingly topical, with a considerable rise in the waste generation, much of which can be attributed to a boom in product packaging (mainly plastic). The annual production of plastics packaging has been constantly increasing over the last 20 to 30 years, and now exceeds 3.7 million tons. Due to a lack of processing technologies and poorly developed selective segregation system, packaging waste is still treated as a part of the municipal solid waste (MSW) stream, most of which is landfilled. As a result of Poland's access to the European Union, previous legal regulations governing municipal waste management have been harmonized with those binding on the member countries. One of the main changes, the most revolutionary one, is to make entrepreneurs liable for environmental risks resulting from the introduction of packaging to the market, and for its recycling. In practice, all entrepreneurs are to ensure recovery, and recycling, of used packaging from products introduced to the market at the required level. In recent year, the required recycling levels were fulfilled for all types of materials but mainly by large institutions using grouped and transport packaging waste for that matter. Household packaging gathered in the selective segregation system at the municipalities was practically left alone. This paper is an attempt to describe the system and assess the first year of functioning of the new, revamped system of packaging waste management in Poland. Recommendations are made relating to those features that need to be included in packaging waste management systems in order to maximize their sustainability and harmonization with the EU legal system.  相似文献   
959.
应用模式识别法研究芳腈化合物结构与活性的关系   总被引:2,自引:0,他引:2  
韩朔睽  许榕 《环境化学》1995,14(3):279-283
基于23个芳腈衍生物对发光菌的毒性疚和一批结构参数,用模式识别法研究了结构与活性的关系。在化合物的生物活性类别与模式特征之间建立的3个类别判别函数对化合物活性类别的判别正确率达91.3%,并为进一步的研究工作合理地挑选了4个代表性化合物。  相似文献   
960.
人口、资源、环境、灾害.这是当今世界考虑人类的生存与发展的四大基本问题,目前均已发出“黄牌警告”.抑制社会与自然向恶性循环方向发展,需唤起全人类的觉醒和国家领导更高的责任感:保护环境和防御大灾.需组织国际交流与协作:协词社会的发展与生存.需促使环保减灾工作纳入发展规划;提高环保减灾的效能.需推动其内部机制走向综合化和社会化,这是90年代国际和国内共同奋斗的目标. 我国是四大基本问题最为严重的少数国家之一,本文列述了有关的一些重要资料,以求在严酷的四大“黄牌”的总况面前.激起社会更广泛的觉醒和行动.最后,简述了对减灾工作的一些设想.  相似文献   
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