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221.
Xiaofei Qin Xijuan Xi Zhongzhi Yang Shishuai Yan Yaxian Zhao Rongguo Wei Yan Li Mi Tian Xingru Zhao Zhanfen Qin Xiaobai Xu 《环境科学学报(英文版)》2010,22(5):744-751
Decabromodiphenyl ether (decaBDE), as a flame retardant, is widely produced and used. To study the thyroid disruption by technical
decaBDE at low concentrations, Xenopus laevis tadpoles were exposed to technical decaBDE mixture DE-83R (1–1000 ng/L) in
water from stage 46/47 (free swimming larvae, system of Nieuwkoop and Faber) to stage 62. DE-83R at concentration of 1000 ng/L
significantly delayed the time to metamorphosis (presented by forelimb emergence, FLE). Histological examination showed that DE-
83R at all tested concentrations caused histological alterations – multilayer follicular epithelial cell and markedly increased follicle size
accompanied by partial colloid depletion and increase in the peripheral colloid vacuolation, in thyroid glands. All tested concentrations
of DE-83R also induced a down-regulation of thyroid receptor mRNA expression. These results demonstrated that technical decaBDE
disrupted the thyroid system in X. laevis tadpoles. Analysis of polybrominated diphenyl ethers (PBDEs) (sum of 39 congeners) in X.
laevis indicated that mean concentrations of total PBDEs in X. laevis exposed to 1, 10, 100, 1000 ng/L were 11.0, 128.1, 412.1, 1400.2
ng/g wet weight, respectively. Considering that PBDEs burden of X. laevis tadpoles was close to PBDEs levels in amphibians as reported
in previous studies, our study has raised new concerns for thyroid disruption in amphibians of technical decaBDE at environmentally
relevant concentrations. 相似文献
222.
Manman Ma Bo Zhang Ye Chen Wenrong Feng Tiezhu Mi Jianhua Qi Wenshuai Li Zhigang Yu Yu Zhen 《Frontiers of Environmental Science & Engineering》2021,15(3):42
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225.
农业文化遗产保护目标下农户生计状况分析 总被引:2,自引:0,他引:2
农户生计是农业文化遗产认定标准之一,也是影响农业文化遗产保护与传承的关键因素,在贫困地区,遗产保护与农户脱贫的两难困境更为突出。本研究基于可持续生计理论和分析框架,以全球重要农业文化遗产地——云南红河哈尼稻作梯田为案例区域,通过生计资本指标体系构建和量化,对比分析了不同生计途径农户的生计状况。评估结果发现,农户的生计资本均值为2.312,生计资本处于匮乏状态,金融资本值最低,而文化资本值最高。从事农业和打工是当前农户的主要生计途径,旅游接待成为生计拓展的重要形式。三类农户生计资本值和家庭年均收入排序相同,都表现为旅游接待户打工兼业户纯农业户,纯农业户的生计状况最差。从单项生计资本看,旅游接待户和打工兼业户的人力资本显著高于纯农业户,物质资本和金融资本比较中,旅游接待户显著高于其他两类农户,说明人力资本越丰富的农户越可能倾向于兼业,农户开展旅游接待需要较高的物质和金融资本作为基础。这意味着,农业文化遗产保护要大力提高农户的农业经营收益,延长农业的价值链和产业链,完善农村金融市场,开展旅游接待培训,从人力、金融等多方面改善农户生计资本状况,实现生计途径拓展。 相似文献
226.
Xiaofeng Zhang Tongxu Liu Fangbai Li Xiaomin Li Yanhong Du Huanyun Yu Xiangqin Wang Chuanpin Liu Mi Feng Bing Liao 《环境科学学报(英文版)》2021,33(2):90-98
Nitrate (NO3?) is known to be actively involved in the processes of mineralization and heavy metal transformation; however, it is unclear whether and how it affects the bioavailability of antimony (Sb) in paddy soils and subsequent Sb accumulation in rice. Here, the effects of NO3? on Sb transformation in soil-rice system were investigated with pot experiments over the entire growth period. Results demonstrated that NO3? reduced Sb accumulation in brown rice by 15.6% compared to that in the control. After amendment with NO3?, the Sb content in rice plants increased initially and then gradually decreased (in roots by 46.1%). During the first 15 days, the soil pH increased, the oxidation of Sb(III) and sulfides was promoted, but the reduction of iron oxide minerals was inhibited, resulting in the release of adsorbed and organic-bound Sb from soil. The microbial arsenite-oxidizing marker gene aoxB played an important role in Sb(III) oxidation. From days 15 to 45, after NO3? was partially consumed, the soil pH decreased, and the reductive dissolution of Fe(III)-bearing minerals was enhanced; consequently, iron oxide-bound Sb was transformed into adsorbed and dissolved Sb species. After day 45, NO3? was completely reduced, Sb(V) was evidently reduced to Sb(III), and green rust was generated gradually. Thus, the available Sb decreased due to its enhanced affinity for iron oxides. Moreover, NO3? inhibited the reductive dissolution of iron minerals, which ultimately caused low Sb availability. Therefore, NO3? can chemically and biologically reduce the Sb availability in paddy soils and alleviate Sb accumulation in rice. This study provides a potential strategy for decreasing Sb accumulation in rice in the Sb-contaminated sites. 相似文献
227.
超旱生植物沙冬青高温胁迫下的快速叶绿素荧光动力学特征 总被引:6,自引:0,他引:6
沙冬青Ammopiptanthus mongolicus是温带荒漠地区唯一的常绿阔叶灌木,由于其生长的沙漠中极端高温远高于其它地区,因此研究沙冬青对高温胁迫的响应特征对于解释植物的抗逆机理具有极为重要的意义.快速叶绿素荧光动力学可以在无损情况下探知叶片光合机构的热损伤程度,JIP-test方法将测量值转化为多种具有生物学意义的参数,因而被广泛应用于高温胁迫的有关研究中.对不同环境条件下快速叶绿素荧光诱导动力学曲线的分析可以深入了解植物光合机构对环境的适应机制.本文利用高频采样叶绿素荧光仪在野外下测定了沙冬青在不同温度处理下的荧光响应情况.研究结果表明,沙冬青耐热性在40~45℃;25℃、30℃及40℃时的F_V/F_M在O.80以上,光合反应正常.50℃时出现高温胁迫特征:1)F_V/F_M降低为0.73;2)OJIP曲线变形为OKJIP曲线,K点出现在300 ms左右,值为245.00;3)反应中心的活性下降,Q_A-的还原速率加快.这些变化是由于光合反应中的电子传递受阻引起的,而光合反应中心并没有被破坏,胁迫条件解除后,光合机构还可恢复,说明沙冬青具有极强耐热性. 相似文献
228.
非洲爪蟾肝细胞原代培养方法 总被引:1,自引:1,他引:0
非洲爪蟾是研究内分泌干扰物的良好模型动物,其体外肝细胞可用于类雌激素活性评价、污染物代谢等研究.论文探讨了非洲爪蟾肝细胞原代培养的方法,采用两步原位灌注法分离非洲爪蟾肝细胞,通过胶原酶的作用使细胞之间解离,后经过一系列转速的离心,获得纯化的肝实质细胞.研究结果表明,采用此法获得的细胞数量为2.5~5×106个,细胞成活率达95%以上,纯度在95%以上,细胞胞体透亮,折光性强,状态良好.培养24h后贴壁较好,每2d换液1次,可培养8~10d,细胞可满足多种后续实验的要求. 相似文献
229.
Katelyn A. Stallings Mi G. Chorzepa 《International Journal of Sustainable Engineering》2019,12(3):189-200
According to the Rubber Manufacturer’s Association, the United States generated 3664 thousand metric tons of scrap tires in 2015. While most waste tires are repurposed, approximately 409.5 thousand metric tons were disposed in landfills. This study investigates an alternative use of the waste tires as a replacement of natural aggregates in concrete mixtures. This study investigated fresh concrete properties and compressive strength. Different coarse and fine aggregate rubber particle sizes were evaluated: 19-mm tire chips (TCs) and 30-mesh crumb rubber (CR). TCs were used to replace coarse aggregates, while CR was used to replace fine aggregate in the concrete mixtures in increments of 10% by volume. Concrete strength loss was reduced with a fine aggregate replacement with CR as opposed to greater losses of strength exhibited by a coarse aggregate replacement with TCs. Adequate strengths were achieved at replacement levels as high as 40% by volume with CR, whereas satisfactory strengths were achieved with only a 10% replacement of coarse aggregates with TCs. Acceptable strengths were obtained from mixtures utilizing a combination of the two rubber sizes. Cement content was observed to have greater influence on rubberized concrete compressive strength at lower rubber contents than higher levels. 相似文献
230.
Hsiao-Hsuan Mi Wan-Ju Wang Sheng-Lun Lin Yi-Chieh Lai John Kennedy Mwangi Lin Chi Wang Guo-Ping Chang-Chien 《Environmental science and pollution research international》2014,21(18):10751-10764
Municipal solid waste incinerators (MSWIs) have long been the major contributors of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) to ambient air in Taiwan. After stringent MSWI emission standards were introduced in 2001, the long-term continuous monitoring of flue gas and ambient air quality became necessary to ensure the effectiveness of the related control strategies. Three MSWIs and the surrounding ambient air were investigated in the current study for PCDD/F characteristics during 2006 to 2011. The average concentrations in the flue gas ranged from 0.008?~?0.0488 ng I-TEQ/Nm3, which is much less than the emission standard in Taiwan (0.1 ng I-TEQ/Nm3) (I-TEQ is the abbreviation of International Toxic Equivalent). This led to extremely low levels in the ambient air, 0.0255 pg I-TEQ/Nm3, much less than the levels seen in most urban areas around the world. Additionally, the results obtained using the Industrial Source Complex Short-Term Dispersion Model (ISCST3) indicate that the PCDD/F contributions from the three MSWIs to the ambient air were only in the range from 0.164?~?0.723 %. Principal component analysis (PCA) showed that the PCDD/Fs in the air samples had very similar characteristics to those from mobile sources. The results thus show that stringent regulations have been an effective control strategy, especially for urban areas, such as Taipei City. 相似文献