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281.
Inflammation is a major adverse outcome induced by inhaled particulate matter with a diameter of ≤ 2.5 µm (PM2.5), and a critical trigger of most PM2.5 exposure-associated diseases. However, the key molecular events regulating the PM2.5-induced airway inflammation are yet to be elucidated. Considering the critical role of circular RNAs (circRNAs) in regulating inflammation, we predicted 11 circRNAs that may be involved in the PM2.5-induced airway inflammation using three previously reported miRNAs through the starBase website. A novel circRNA circ_0008553 was identified to be responsible for the PM2.5-activated inflammatory response in human bronchial epithelial cells (16HBE) via inducing oxidative stress. Using a combinatorial model PM2.5 library, we found that the synergistic effect of the insoluble core and loaded Zn2+ ions at environmentally relevant concentrations was the major contributor to the upregulation of circ_0008553 and subsequent induction of oxidative stress and inflammation in response to PM2.5 exposures. Our findings provided new insight into the intervention of PM2.5-induced adverse outcomes.  相似文献   
282.
以石煤渣为主要原料研制应用于工业窑炉的保温材料,具有较高的耐压强度和使用温度,导热率低。本文通过分析各原料的主要作用,研究了不同原料掺量对材料性能的影响,从而得到了石煤渣保温材料合理的配方范围为:石煤渣40%~60%、可燃造孔物30%~40%、粘结剂12%~20%、外加剂0.10%~0.20%。  相似文献   
283.
Plant species composition and species number were studied in two types of field margins: 31 arable field margins and 33 road verges. Both field margin types were adjacent to intensively managed grass or cereal fields. Effects of eight variables on field margin vegetation were studied. Despite having many plant species in common, composition and species number differed between the two field margin types, due to different ecological conditions and margin management. Arable field margins were composed of tall and/or nutrient demanding ubiquitous species and were characterised by species of later successional stages than those of road verges. The vegetation of road verges was lower and species numbers were higher than in arable field margins. The road verges contained several semi-natural meadow species that are declining in abundance. A CCA ordination of the field margins and the recorded variables showed that plant species composition was significantly affected by thickness of litter, slope, width, moisture level and type of crop in the adjacent field. Number of plant species was significantly higher in mown than unmown margins and generally higher in margins adjacent to fields with mainly grass production than in margins adjacent to fields with mainly cereal crops. In order to preserve botanical diversity in this agricultural landscape, the maintenance of regularly mown road verges should be prioritized.  相似文献   
284.
日本东京湾地区冬季飘尘污染研究   总被引:3,自引:1,他引:3  
对东京湾地区冬季高浓度飘尘污染进行了分析,研究结果表明,日本某些特定地区也存在着与中国严重污染城市相当的飘尘污染;分析指出高浓度的飘尘污染主要来自于人为污染,其中废弃物焚烧和汽车排气的贡献占重要地位,这与中国大气煤烟型污染截然不同。  相似文献   
285.
勃利县钢铁厂炼铁车间,每年都要排出四万多立方米的急冷水萃矿渣,污染河流、吞食耕田,不能充分有效利用.然而利用钢铁厂碱度大于1.4的急冷水萃矿渣和勃利县的斜发沸石为主要成分,加入适量的有机和无机助剂,经过特殊工艺,复合制成的新型砂浆及混凝土的掺和料,无毒无味,充分利用了钢铁厂的废渣,变废为宝.用该掺和料配制的不同强度等级的抹面砂浆、砌筑砂浆,不仅可以大量取代水泥,降低工程造价,而且可以改变砂浆的和易性、保水性,提高砂浆的强度和耐久性.  相似文献   
286.
高浓度酸性含铁废水处理的试验研究   总被引:6,自引:0,他引:6  
采用中和氧化絮凝工艺对高浓度酸性含铁废水进行了处理,用10?(OH),乳液作中和沉淀剂,Na2SiO2作助凝剂,对Ca(OH)2与Na2SiO3的配比、pH值、絮凝剂和氧化剂的投加量等条件进行了优选,并用该工艺在生产现场进行试运行,出水中各项指标均达到国家排放标准。  相似文献   
287.
苏北沿海沉积物的化学组成和重金属特征   总被引:5,自引:0,他引:5  
苏北沿海沉积物的主要矿物组成为石英、伊利石、高岭石和绿泥石,主元素化学成分变化较大,反映沉积物物质组成差异大。重金属元素分析显示,Cd的富集系数明显高于其它元素,较高的还有Cu和Cr,Hg元素大多低于背景值;连云港、射阳、启东三个地方的变异系数较高,反映它们受人类活动影响大。比较连云港区沉积物不同时间的重金属含量发现,几乎所有重金属都明显增加,特别是新港区。对照沉积物质量标准,Cr的污染最严重,其次是Cd、Cu和As。  相似文献   
288.
This article presents an investigation of relationships between organic farming and landscape composition in Denmark. Landscape composition was analysed in terms of density of uncultivated landscape elements (I), number of land uses per hectare (II), diversity of land use (III) and mean field size (IV). Two analytical approaches were used. The first was based on an examination of the national agricultural registers for 1998, 2001 and 2004. The second approach used aerial photo interpretation for an analysis of 72 conventional and 40 organic farms within three sample areas for 1982, 1995 and 2002. The national analysis indicated that organic farming has a direct effect on landscape composition. In 2001, organic farms were characterised by a higher number of land uses per ha, a higher land use diversity and smaller mean field sizes. From 1998 to 2004, conversion to organic farming was related to an increasing number of land uses per ha, increasing land-use diversity and decreasing mean field sizes. Relationships between organic farming and landscape composition were independent of variations in regional location, farm size or farm size change. At the level of sample areas, a significant relationship between organic farming and landscape composition was only found for densities of small biotopes. However, when differences in farm size and physical geographical conditions between conventional and organic farms were taken into account, several significant differences in landscape composition were clarified in two of the three sample areas. Furthermore, changes in landscape composition following conversion to organic farming were largely biased by the characteristics of the sample areas. Thus, in contrast to the national level, the sample area study indicated that differences in landscape composition between organic and conventional farms were not a direct implication of organic farming practices, but were related to variations within other parameters and to the location of organically farmed land.  相似文献   
289.
以活性炭纤维(ACF)为溶液中铁离子的吸附剂,考察了吸附时间、吸附温度、ACF比表面积及表面酸碱性对Fe3 吸附行为的影响.通过平衡吸附实验获得的吸附等温线,并不符合Langmuir与Freundlich经验吸附方程.吸附温度升高与ACF比表面积增加,都有利于铁离子的吸附,说明吸附过程同时具备物理和化学吸附行为的双重特征.ACF表面碱性基团是影响铁离子吸附的主要因素.  相似文献   
290.
应用陆地卫星TM图象编制闽北土壤图(1:10万)的方法研究   总被引:1,自引:0,他引:1  
以TM原图象合成的标准假彩色和似自然色图象作目视解译为主,根据土壤及其相关地物的野外光谱测定数据,分析其影象色调特征;用TM 7个波段原始黑白图象作对比解译,以预测不同地物的彩色合或效果并选择最佳合成方案;用TM6热红外图象作假彩色等密度分割处理,以提取随海而异的地面温度场和土壤类型垂直分带信息;用TM比值图象及其假彩色合成处理,以逐步增强并提取土壤信息;最后参照同比例尺地质图和地形图等相关资料,完成土壤图的编制。  相似文献   
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