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351.
毒死蜱是目前全世界使用和销售量最大的有机磷杀虫剂之一。为探讨围生期毒死蜱暴露致8周雄性子鼠睾丸组织的氧化损伤,选择健康Wistar妊娠母鼠于妊娠期(gestation days,GD)第6天至子鼠出生后(postnatal days,PND)21天通过灌胃染毒0、0.75、1.35和2.70 mg·kg~(-1)剂量的毒死蜱,待雄性子鼠8周龄取左侧睾丸实施组织病理学检查,右侧睾丸用以检测丙二醛(maleic dialdehyde,MDA)的含量和谷胱甘肽S转移酶(glutathione S transferases,GST)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)、总超氧化物歧化酶(total superoxide dismutase,T-SOD)的活力。结果表明,与对照组比较,随着染毒剂量的增加子鼠体重和睾丸、附睾脏器系数有下降的趋势(P0.05);而MDA呈升高趋势(P0.05)。各组T-SOD和1.35、2.70 mg·kg~(-1)剂量组GSH-Px活力的下降及2.70 mg·kg~(-1)剂量组GST活力的升高均有统计学意义(P0.05)。睾丸组织病理学检查结果可见2.70mg·kg~(-1)剂量组睾丸组织有明显的损伤,管腔中精液量减少,生精细胞脱落增多。上述研究结果提示母鼠于围生期暴露于毒死蜱,可通过氧化损伤诱导子代雄性大鼠睾丸的毒性作用。 相似文献
352.
The pollution status and characteristics of PAEs (phthalate esters) were investigated in indoor air of offices, and PAEs of both gas-phase and particulate-phase were detected in all the samples. The concentration (sum of the gas phase and the particulate phase) was 4748.24 ng/m3, ranging between 3070.09 and 6700.14 ng/m3. Diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate were the most abundant compounds, together accounting for 70% of the Σ6PAEs. Dividing the particulate-phase PAEs into four size ranges (<2.5, 2.5-5, 5-10, >10 μm), the result indicated that PAEs in PM2.5 were the most abundant, with the proportion of 72.64%. In addition, the PAE concentration in PM2.5 correlated significantly with the total particulate-phase PAEs (R2 = 0.85). Thus, the amount of PAEs in PM2.5 can be estimated from the total amount of particulate-phase PAEs using this proportion. In a comparison between the offices and a newly decorated study room, it was found that pollution characteristics were similar between these two places. Thus, it is implied that the PAE concentration decreased by 50% 2 yr after decorating. 相似文献
353.
Yongsheng Zhang Lilin Zhao Ruitao Guo Na Song Jiawei Wang Yan Cao William Orndorff Wei-ping Pan 《环境科学学报(英文版)》2015,27(7):156-162
In this study, the mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor were investigated through thermal decomposition methods. The results show that the mercury adsorption performance of the HBr-modified fly ash was enhanced significantly. The mercury species adsorbed by unmodified fly ash were HgCl2, HgS and HgO. The mercury adsorbed by HBr-modified fly ash, in the entrained-flow reactor, existed in two forms, HgBr2 and HgO, and the HBr was the dominant factor promoting oxidation of elemental mercury in the entrained-flow reactor. In the current study, the concentration of HgBr2 and HgO in ash from the fine ash vessel was 4.6 times greater than for ash from the coarse ash vessel. The fine ash had better mercury adsorption performance than coarse ash, which is most likely due to the higher specific surface area and longer residence time. 相似文献
354.
Min Song Chenchen Chi Min Guo Xueqing Wang Lingxiao Cheng Xueyou Shen 《环境科学学报(英文版)》2015,28(2):157-162
The pollution status and characteristics of PAEs(phthalate esters) were investigated in indoor air of offices, and PAEs of both gas-phase and particulate-phase were detected in all the samples. The concentration(sum of the gas phase and the particulate phase) was4748.24 ng/m3, ranging between 3070.09 and 6700.14 ng/m3. Diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate were the most abundant compounds, together accounting for 70% of the ∑ 6PAEs. Dividing the particulate-phase PAEs into four size ranges( 2.5, 2.5–5, 5–10, 10 μm), the result indicated that PAEs in PM2.5were the most abundant,with the proportion of 72.64%. In addition, the PAE concentration in PM2.5correlated significantly with the total particulate-phase PAEs(R2= 0.85). Thus, the amount of PAEs in PM2.5can be estimated from the total amount of particulate-phase PAEs using this proportion. In a comparison between the offices and a newly decorated study room, it was found that pollution characteristics were similar between these two places. Thus, it is implied that the PAE concentration decreased by 50% 2 yr after decorating. 相似文献
355.
The concentrations of phthalate esters(PAEs) in Chinese hospitals were investigated by simultaneously determining concentrations of gas- and particle-phase PAEs. PAEs were detected in two third-class first-grade hospitals, two second-class first-grade hospitals, and a community health service center. Hospital drugstores had the highest concentration(24.19 μg/m3), which was 1.54 times that of newly decorated houses. The second highest concentration was found in the transfusion rooms, averaging 21.89 μg/m3; this was followed by the concentrations of PAEs in the nurse's workstations, the wards, and the doctor's offices, with mean concentrations of 20.66, 20.0, and 16.92 μg/m3, respectively. The lowest concentrations were found in the hallways(16.30 μg/m3). Of the six different kinds of PAEs found, major pollutants included diethyl phthalates, dibutyl phthalates, butylbenzyl phthalates and di(2-ethylhexyl) phthalates, comprising more than 80% of all PAEs present.Meanwhile, a comparison between different wards showed that PAE concentrations in the maternity wards were 1.63 times higher than in the main wards. Based on known health hazards, our results suggest that the PAEs seriously influence the health of the pregnant women and babies; therefore, it is of great importance to take the phthalate concentrations in hospitals into consideration. In addition, hospital indoor air was more seriously contaminated than the air of newly decorated houses. 相似文献
356.
目的研究采样频率为2~10 MHz的64通道超高速同步瞬态测试系统的设计技术,实现两类典型超高速瞬态测试系统的硬件架构设计与软件架构设计。方法一类采用PXI-Express高带宽总线和高速RAID磁盘阵列架构构建持续流盘存储的连续高速测试系统,另一类是采用大容量板载数据缓存和PXI总线事后下载传输数据的架构构造高速测试系统。在高性能测试软件设计方面,主要应用生产者/消费者结构与有限状态机相结合的软件架构进行高性能测试系统软件设计。结果目前64通道下基于持续流盘架构的测试系统受数据记录的速度限制系统最高采样频率仅达2.5 MHz,而基于板载缓存数据与PXI总线事后下载数据架构的测试系统最高采样频率可达10 MHz,测试时长可达5 s。结论当前两类架构的测试系统均可满足超高速瞬态测试需求,设计时需根据需求的最高采样频率决定使用的架构形式。 相似文献
357.
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359.
城市大气污染治理研究多年来未见突破,为了解决城市大气污染给人们生活带来的危害,利用提高生态修复主体利用率的方法,研究出一种新的城市大气污染治理方法——“城市新风系统”,这种方法理论上可以快速有效改善城市区域内大气环境.该研究以南京为例进行模拟计算,并建立了理论模型的雏形.理论模型预期可在数周内改善城市大气环境,并通过污染与新风总量的科学控制实现范围内的全优环境,这是一个具有可复制性,并有极强的推广意义的方法. 相似文献
360.
Geosmin is a secondary metabolite responsible for earthy odors. The occurrence of geosmin has great impact on the quality of water environment. The gene essential for geosmin biosynthesis have been identified in several species. But little is known about the mechanism of geosmin synthesis in Aphanizomenon gracile. This study attempted to clone the gene involved in geosmin biosynthesis of Aphanizomenon gracile a nd a nalyze t he geosmin production u nder d ifferent e nvironments. T he high-efficiency thermal asymmetric interlaced PCR (hiTAIL-PCR) was used to amplify the full-length of geosmin synthase gene from Aphanizomenon gracile (WH-1). Real time PCR (RT-PCR) was applied to quantify the geosmin production in different light and temperature. As a result, geo, a geosmin synthase gene from Aphanizomenon gracile (WH-1) was cloned by hiTAIL-PCR. The full-length open reading frame (ORF) of geo was 2 262 bp, coding for a protein of 753 amino acids. Meanwhile, WH-1 was treated with different environment conditions and mRNA expression levels of geo were quantified by RT-PCR. It was found that low temperature (15 °C), high light intensity (35 μmol m-2 s-1) and continuous light illumination were beneficial to the expression of geo. The successful amplification of geosmin synthase gene verified that hiTAIL-PCR is an effective and simple procedure of low cost. The result provides fundamental knowledge on the monitoring and prevention for odorants. 相似文献