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541.
542.
为了分析苯系物(BTEXs)联合暴露后仿刺参(Apostichopus japonicus)管足转录组差异表达基因,采用Illumina Hi SeqTM2000测序技术,对1.0 mg·L~(-1)苯系物(B)联合暴露12 h后和对照组(C)的仿刺参管足组织分别进行转录组测序。经Trinity软件进行de novo组装,获得了145 675条unigenes。利用公共数据库进行同源比对,共注释了35 330条unigenes。对比分析苯系物联合暴露组和对照组的转录组测序结果,获得了2 418个差异表达基因(DEGs)(|Log2Fold changes|≥1且FDR≤0.001),其中,上调表达和下调表达基因分别为1 049和1 369个。GOseq分析结果显示,158个DEGs显著富集在149个GO terms中,包括103个生物学过程、17个细胞组分和29个分子功能(P0.05);KEGG代谢通路分析结果显示994个差异基因映射到268条代谢通路,这些差异表达基因参与的生理过程与其他生物的同源基因参与的信号传导、癌症、外源性化合物的生物降解代谢等过程相类似。上述结果为在转录组水平筛选苯系物的生物标志物,解析苯系物对仿刺参毒性作用的分子机制提供了科学参考。 相似文献
543.
有机质对Cu2+在棕壤及其各粒级微团聚体中吸附解吸特性的影响 总被引:2,自引:0,他引:2
采用平衡液吸附法和NH4AC、EDTA溶液解吸法,研究了有机质对Cu2+在棕壤及其各粒级微团聚体中(<10 μm,10~50μm,50~250 μm)的吸附解吸过程中的影响,为寻求有效控制土壤中Cu2+环境行为的对策措施提供理论支撑.研究结果表明,各粒级微团聚体中有机质对Cu2+的吸附能力随粒级的减小而增强,原土仅次于<10 μm微团聚体.就吸附机制而言,去除有机质后的原土及其各粒级微团聚体在不同吸附机制控制下的吸附能力也有所变化,表现为:去除有机质后,棕壤及各粒级微团聚体对Cu2+的静电吸附能力增强,络合吸附能力和专性吸附的能力均有所降低.分析表明,原土及其不同粒级微团聚体对Cu2+的吸附能力及稳定性的差异,与其重要组成成分有机质有关. 相似文献
544.
上转换发光剂掺杂纳米TiO2的制备及可见光降解乙基紫的研究 总被引:1,自引:0,他引:1
合成了一种新型含有稀土金属Er的上转换发光剂40CdF2·60BaF2·1.6Er2O3,此上转换发光剂在488 nm可见光的激发下,产生了5个波长均小于387 nm的上转换紫外光发射峰.采用超声波分散的方法制备出了上转换发光剂掺杂的纳米TiO2可见光光催化剂.利用X-射线衍射(XRD)及透射电镜(TEM)对催化剂进行了表征.以乙基紫染料为研究对象,研究了在(三基色灯下发出的)可见光的照射下该可见光光催化剂的催化降解性能,并与未掺杂的纳米TiO2粉末的催化性能进行了对比.结果表明,作为掺杂成分的上转换发光剂可有效地将可见光转化为紫外光并被纳米TiO2粉末吸收利用,在可见光照射12.0 h后乙基紫降解率达到了99.68%,大大高于未掺杂纳米TiO2时的降解率. 相似文献
545.
Human milk survey for dioxins in the general population in Japan 总被引:1,自引:0,他引:1
BACKGROUND: Much attention has been paid to the level of dioxins in breast milk in Japan but few large-scale studies have been conducted on the subject. METHODS: From 1997 to 2002, we collected 839 samples of breast milk from primiparas residing throughout Japan. Starting in 1999, breast milk was also collected from secundiparas. Seven isomers of polychlorinated dibenzo-p-dioxins (PCDDs), 10 of polychlorinated dibenzofurans (PCDFs), 4 of coplanar polychlorinated biphenyls (Co-PCBs) and 8 of mono-orthochlorinated polychlorinated biphenyls (mono-ortho PCBs) were analyzed by employing gas chromatography and mass spectrometry. A correlation between the level of dioxins in human milk and the age of the mothers was noted for the primiparas and the secundiparas; and the levels were compared between the first and the second deliveries. Grouped by parity and prefecture in each year, observations were also made on the trends in these levels. Dioxin levels are shown by using geometric means because their distributions were skewed to the left. RESULTS: The sum of PCDDs and PCDFs, Co-PCBs, mono-ortho PCBs, and total dioxins in the breast milk of primiparas were 13.9, 5.4, 3.4, and 22.7 pg TEQ/g fat, respectively. In the samples obtained from secundiparas, these levels were 63-68 percents of those taken from the primiparas. The correlation coefficients between the PCDDs/DFs, Co-PCBs, mono-ortho PCBs, and total dioxins and the age of the primiparas were 0.19, 0.17, 0.36, and 0.24, respectively. All these correlations were statistically significant (p < 0.001). The positive correlations between these contaminants and the age of the secundiparas were also examined. The total dioxins as well as PCDDs/DFs, Co-PCBs, and mono-ortho PCBs in the breast milk of the primiparas declined significantly between 1998 and 2002 (regression coefficients: -0.04, -0.05, -0.03, and -0.03, respectively). However, no significant decline in these levels was observed when sorted by prefectures. CONCLUSIONS: Much attention should be paid to the age and parity of nursing mothers when investigating the relationship between the level of dioxins in breast milk and the body burden of infants. 相似文献
546.
沈阳细河流域土壤和作物中汞的潜在生态危害及健康风险评价 总被引:1,自引:0,他引:1
为研究沈阳市细河流域土壤汞(Hg)的污染和健康风险状况,对该区土壤和农作物中Hg的含量和分布进行了调查和分析。采用Hakanson潜在生态风险危害指数法评价土壤Hg的污染状况,并利用健康风险评价模型对Hg通过不同暴露途径所引起的健康风险作出评价。研究结果表明,细河流域土壤Hg的潜在生态危害相对较大,其中43.21%样品处于中等危害程度,26.62%属于强及以上风险级别。健康风险评价模型计算表明,人体经食物摄取是土壤Hg暴露的主要途径,Hg日平均暴露剂量依次为食物摄取呼吸暴露皮肤暴露;成人和儿童的非致癌危害指数分别为0.315和0.713,均低于风险阈值1,表明Hg不会对人体造成健康危害。 相似文献
547.
Xiangyu Guan Fei Liu Yuxuan Xie Lingling Zhu Bin Han 《Environmental geochemistry and health》2013,35(4):535-549
Pollution of groundwater with chlorinated aliphatic hydrocarbons (CAHs) is a serious environmental problem which is threatening human health. Microorganisms are the major participants in degrading these contaminants. Here, groundwater contaminated for a decade with CAHs was investigated. Numerical simulation and field measurements were used to track and forecast the migration and transformation of the pollutants. The diversity, abundance, and possible activity of groundwater microbial communities at CAH-polluted sites were characterized by molecular approaches. The number of microorganisms was between 5.65E+05 and 1.49E+08 16S rRNA gene clone numbers per liter according to quantitative real-time PCR analysis. In 16S rRNA gene clone libraries constructed from samples along the groundwater flow, eight phyla were detected, and Proteobacteria were dominant (72.8 %). The microbial communities varied with the composition and concentration of pollutants. Meanwhile, toluene monooxygenases and methane monooxygenases capable of degradation of PCE and TCE were detected, demonstrating the major mechanism for PCE and TCE degradation and possibility for in situ remediation by addition of oxygen in this study. 相似文献
548.
549.
2003年是中国历史上不平凡的一年。先是突如其来的“非典”,后是新疆巴楚-伽师、青海德令哈和云南大姚地震。到了7—8月的主汛期,大江大河安澜度过,人们迎着凉凉的秋风,把自然灾害的伤痛留给了历史。 相似文献
550.
The bronchial dosimeter for Rn progeny proposed by Yu and Guan in 1998 was employed to survey the bronchial dose from Rn progeny in 30 residences in Hong Kong. An average bronchial deposition fraction of Rn progeny was obtained as 0.0334, which gave an average dose conversion factor (DCF) of 8.5 mSv WLM-1. The mean values of potential alpha energy concentration (PAEC) deposited in the tracheobronchial region (PAECT-B), total PAEC in air (PAECT), annual effective dose (E), concentration of Rn gas (RC) and annual dose conversion factor (ADCF) for all the residential sites combined were 0.11 +/- 0.05, 3.1 +/- 1.4 mWL, 1.2 +/- 0.5 mSv yr-1, 23 +/- 10 Bq m-3 and 0.055 +/- 0.020 (mSv yr-1 per Bqm-3), respectively, with air-conditioned sites (AC sites) and non-AC sites having significantly different mean ADCF values. The indoor relative humidity affected PAECT and RC with high confidence levels (> 95%). 相似文献