细化搜索
结果 4381-4390 的 6,558
Acrolein exerts a genotoxic effect in the Leydig cells by stimulating DNA damage-induced apoptosis 全文
2020
Yildizbayrak, Nebahat | Orta-Yilmaz, Banu | Aydin, Yasemin | Erkan, Melike
Acrolein is a highly reactive unsaturated organic molecule and has harmful effects on human health. Acrolein is generally formed in heat-treated foods above 150 °C, as well as in the combustion of gasoline, wood industry, plastic waste, and tobacco smoke. In this study, the effects of acrolein on genotoxicity in Leydig cells and the underlying mechanisms are aimed to be clarified. In addition, the toxicogenomic profile of acrolein was studied in terms of both apoptosis and steroidogenesis. Real-time PCR and ELISA tests were used to analyses of steroidogenic endpoints. Apoptosis was evaluated with double fluorescence staining and gene expression analyses of related genes. Comet assay was used to determine the genotoxicity. The results showed that acrolein caused concentration-dependent inhibition on cell viability at 8 μM and above concentrations, decreased testosterone production at 13.6 and 19.7 μM concentrations, and suppressed expression levels of genes that play an important role in steroidogenic pathway. Furthermore, acrolein downregulated expression of anti-apoptotic Bcl2 gene and upregulated expression of pro-apoptotic Bax, Casp3, and Trp53 gene after 24-h treatment in 7.4, 13.6, and 19.7 μM acrolein-exposed Leydig cells. The results of comet assay showed that acrolein significantly induced tail length, tail % DNA, and Olive tail moment. Overall, it was concluded that acrolein-induced cell damage in Leydig cells may be due to formation of genetic damage in steroidogenesis and apoptosis.
显示更多 [+] 显示较少 [-]The knowledge domain and emerging trends in phytoremediation: a scientometric analysis with CiteSpace 全文
2020
Zhang, Yu | Li, Chen | Ji, Xiaohui | Yun, Chaole | Wang, Maolin | Luo, Xuegang
As a cost-effective, environmentally friendly remediation technology, phytoremediation is defined as the use of green plants to remove pollutants from the environment or render them harmless and has been applied to a variety of contaminated sites throughout the world. There is a prominent phenomenon in which publications about phytoremediation increase each year and involve an increasing number of subject categories. This paper adopts the scientometric analysis method to assess the current state and explore the trends of phytoremediation research based on the bibliographic records retrieved from the Web of Science Core Collection (WoSCC). The results of this paper clearly answer the following questions. (1) What are the publishing characteristics of research on the topic of phytoremediation? What are the characteristics of academic collaboration in phytoremediation research? (2) What are the characteristics and development trends of phytoremediation research? (3) What are the hotspots and frontiers of phytoremediation research? Overall, the research method provides a new approach for the assessment of the performance of phytoremediation research. These results may help new researchers quickly integrate into the field of phytoremediation, as they can easily grasp the frontiers of phytoremediation research and obtain more valuable scientific information. This study also provides references for the follow-up research of relevant researchers.
显示更多 [+] 显示较少 [-]Biochar-related studies from 1999 to 2018: a bibliometrics-based review 全文
2020
Li, Dongyang | Zhao, Rui | Peng, Xing | Ma, Zhifei | Zhao, Ying | Gong, Tiancheng | Sun, Mengyang | Jiao, Yuxin | Yang, Tianxue | Xi, Beidou
Biochar has been paid great attentions during the last two decades, because of its resources potentials and environmental benefits. A bibliometric analysis was applied to assess the publications regarding the keyword biochar from the Web of Science database during the period of 1999 to 2018. A total of 8629 publications were obtained with a rapid increase of annual citations and number of papers. The research topics were diversified, which were mainly divided into “Environmental Sciences and Ecology,” “Agriculture,” and “Engineering.” Bioresource Technology was the journal which published most of the relevant papers. China ranked first in the number of published papers, followed by the USA, Australia, UK, and Germany. Especially, China established close collaboration with the USA in joint publication. Analysis of the keywords indicated that biochar production, comparative sorption, soil-applied black carbon, and soil management were the main research hotspots of biochar. The burst detection reflected that the innovation of biochar production and the new application field of biochar was the future research trends. These results can provide insight into the research progress regarding biochar.
显示更多 [+] 显示较少 [-]The willingness and perception of people regarding green roofs installation 全文
2020
Sarwar, Suleman | Alsaggaf, Majid Ibrahim
Developing economies are facing multifaceted problems like dramatic increase in motorized traffic, urban heat island, urban sprawl, and climatic changes. Environmental Performance Index report states that Pakistan is on 169 among 180 countries due to ill-planned development on prime agriculture land, poor air, water quality, and jeopardizing ecosystem of the country. The change of land uses from the natural to the built environment has created problems like loss of vegetation and habitat, enlarged surface flow, and heavy floods. However, this study addresses this core issue by taking responses from the residents of Lahore, Pakistan. Current research focuses on the willingness and perception of residents regarding the adaptation of green roof technology. The resident perceptions are obtained by a structured questionnaire and analyzed by using statistical techniques. The findings of the research highlight that adaptation of green roof is primarily linked with the four factors, i.e., awareness of green roof among all stakeholders, special provision in building regulation concerning green roof, sustainable environmental consciousness, and subsidized cost of green roof materials.
显示更多 [+] 显示较少 [-]Pelagic Sargassum spp. capture CO2 and produce calcite 全文
2020
Paraguay-Delgado, Francisco | Carreño-Gallardo, Caleb | Estrada-Guel, Ivanovich | Zabala-Arceo, Alberto | Martinez-Rodriguez, Harby Alexander | Lardizábal-Gutierrez, Daniel
Pelagic Sargassum is considered an ecological plague that is causing adverse economic impacts to the tourist and fishing industries in the Caribbean. However, its proliferation might be playing an important role to reduce global warming, as it removes a high content of CO₂ from the atmosphere and transforms it into calcium carbonate, in its calcite phase, producing sediment after it dies. We quantified the amount of calcite in Sargassum samples collected from the Mexican Caribbean coast in 2019. Samples were divided into three parts: vesicles, thallus, and leaves. In each part, the amount of carbon, oxygen, and calcium was determined by means of X-ray energy dispersion to confirm the existence of a calcite crystalline phase. Imaging methodologies and IR spectroscopy complemented the structural studies. The thermogravimetric analysis determined that approximately 5% of the CO₂ captured by the Sargassum was converted into calcite. Thus, by extrapolation, the Atlantic Sargasso Belt retained approximately 19.3 million tons of CO₂ from 2011 to 2019.
显示更多 [+] 显示较少 [-]Oxidation of nine petroleum hydrocarbon compounds by combined hydrogen peroxide/sodium persulfate catalyzed by siderite 全文
2020
Li, YueHua | Zhao, Lin | Chen, Fulong | Jin, Kylan S. | Fallgren, Paul H. | Ma, Yukun
A system consisting of hydrogen peroxide/persulfate (H₂O₂/S₂O₈²⁻) catalyzed by siderite was attempted to oxidize nine representative petroleum hydrocarbon compounds [benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene, 1,2,4-trimethylbenzene, methyl-tert-butyl ether, and naphthalene] that tend to persist in the environment. Oxidation under different siderite dosages, H₂O₂:S₂O₈²⁻ ratios, and pH conditions were investigated. Results indicated that oxidation rates increased from 1.21–4.62 to 1.77–8.94 d⁻¹ as siderite increased from 0.16 to 0.48 g/40 mL (H₂O₂:Na₂S₂O₈ = 5:1, initial pH = 3.0), except for naphthalene (decreased from 0.58 to 0.45 d⁻¹ with increased siderite dosage). When the H₂O₂:S₂O₈²⁻ ratio was increased from 1:1 to 5:1 (siderite = 0.16 g, initial pH = 3.0), the oxidation rates increased from 0.02–0.73 to 0.33–2.19 d⁻¹. However, as pH increased to > 5.5 (siderite = 0.16 g, H₂O₂:Na₂S₂O₈ = 2.5:1), the oxidation rates of petroleum hydrocarbons decreased to 0.003–0.09 d⁻¹, which was approximately 90% less than that at pH = 3.0. The partial correlations and principal component analysis of the experimental data were conducted. Overall, both siderite dosage and H₂O₂:S₂O₈²⁻ ratio correlated positively with oxidation efficiency. The oxidation potential by H₂O₂/S₂O₈²⁻ mixtures towards the target petroleum hydrocarbon compounds seemed to be more sensitive to pH conditions than to siderite dosages or H₂O₂:S₂O₈²⁻ ratios.
显示更多 [+] 显示较少 [-]Urinary organophosphate metabolites and oxidative stress in children living in agricultural and urban communities 全文
2020
Sapbamrer, Ratana | Hongsibsong, Surat | Khacha-Ananda, Supakit
Exposure to organophosphate (OP) pesticides in children may increase oxidative stress, resulting in the development of chronic diseases. This study aims to compare urinary OP metabolites and oxidative stress between children in agricultural and urban communities. The study also investigated the factors associated with urinary OP metabolites among children. Urine samples were collected from children for measuring levels of OP metabolites, glutathione (GSH), and malondialdehyde (MDA). The remarkable findings were that total dialkylphosphate (DAP) levels detected among children in this agricultural community were significantly higher than those from the urban community (P = 0.001). Multiple linear regression showed that total diethylphosphate (DEP) levels among children in the agricultural community were negatively associated with distances from children’s residence to the agricultural fields (β ± SE. = − 1.535 ± 0.334, 95%CI = − 2.202, − 0.863) and positively associated with playing on farms (β ± SE. = 0.720 ± 0.342, 95%CI = 0.036, 1.405). In addition, total dimethylphosphate (DMP) levels were positively associated with children working on farms (β ± SE. = 0.619 ± 0.264, 95%CI = 0.091, 1.147). Importantly, GSH levels among children in the agricultural community were significantly lower than those in the urban community (P < 0.001), but MDA levels did not differ. These results therefore suggest that children can be exposed to OPs both outdoors and indoors. Our results also provide supporting evidence that OP exposure can cause oxidative stress in children. As oxidative stress contributes to several chronic diseases, a good proposed strategy for the future would include measurement of oxidative stress biomarkers among children exposed to OPs as an early warning of chronic diseases.
显示更多 [+] 显示较少 [-]From race-to-the-bottom to strategic imitation: how does political competition impact the environmental enforcement of local governments in China? 全文
2020
Zhang, Zhenbo | Jin, Taijun | Meng, Xiaohua
In China, national environmental regulations have customarily found themselves to be inhibited by local government’s ostensible obedience. This research investigates how local officials, motivated and constrained by political competition, dedicate themselves to the environment and interact with each other regarding environmental regulation implementation and actual regulatory performance. Based on a spatial econometric model using data from 30 provinces from 2000 to 2016, the empirical results document the spatial dependence of environmental regulatory enforcement among provinces of similar economic levels and reveal that since 2007, there has been a performance-oriented peer competition for SO₂ emission reduction but no similar competition for CO₂ emission reduction. The findings indicate a transformation of the regulatory behavior of local governments from a race-to-the-bottom to strategic imitation and provide institutional insight into the spatial attributes of environmental enforcement under the impact of the political regime in China.
显示更多 [+] 显示较少 [-]Female parliamentarians and environmental performance: the role of the income threshold 全文
2020
Lv, Zhike | Gao, Zhenya | Xu, Ting
This paper investigates whether the effect of female parliamentarians on environmental performance differs by the level of income. To that end, a threshold estimation approach is applied to a panel of 91 countries over the period 2002–2012. The results suggest the existence of income threshold effects in female parliamentarians-environmental performance nexus. Specifically, when it is above the income threshold value, the extent of this positive correlation is much greater than below it. It means that theoretically although the female parliamentarians have a higher awareness of environmental protection and a positive effect on environmental performance than men, the economic development of countries will affect the implementation of this effect. Countries tend to prioritize economic development when income levels are low, only in high-income countries will the proportion of female parliaments significantly improve the country’s environmental performance. These results provide some important implications for policymakers when considering the relationship between female parliamentarians and environmental performance.
显示更多 [+] 显示较少 [-]The positive effect of siderite-derived α-Fe2O3 during coaling on the NO behavior in the presence of NH3 全文
2020
Shu, Daobing | Liu, Haibo | Chen, Tianhu | Chen, Dong | Zou, Xuehua | Wang, Can | Li, Mengxue | Wang, Hanlin
Siderite is a naturally occurring mineral that can be found extensively in coal. The structural evolution of siderite in the process of coaling and its performance in the transformation of NO in the presence of NH₃ were investigated in this work. In addition, the effects of the coexisting component, including vapor, SO₂, and the alkali metal K, were also discussed. Heat treatment was performed at 450, 500, 550, 600, and 700 °C to obtain siderite-derived α-Fe₂O₃, which was then evaluated in de-NOₓ via the selective catalytic reduction (SCR) of NO with NH₃ in a fixed bed. The X-ray diffraction (XRD), the X-ray fluorescence spectrometer (XRF), N₂ adsorption-desorption (BET), the X-ray photoelectron spectrometer (XPS), the scanning electron microscope (SEM), and the transmission electron microscope (TEM) were used to investigate the variations in the morphology and structure of the thermally treated siderite. The results showed that siderite was gradually oxidized and decomposed into α-Fe₂O₃ with a nanoporous structure and large surface area of 27.27 m² g⁻¹ after calcination under an air atmosphere. The α-Fe₂O₃ derived from siderite at 500 °C (H500) exhibited an excellent SCR performance, where the NO conversion rate was great than 90% between 250 and 300 °C due to the pore structure and high specific surface area, additional adsorbed oxygen states, abundant oligomeric Fe oxide clusters, and large amount of acid sites. Regardless of the vapor content, SO₂ concentration, and reaction temperature, the α-Fe₂O₃ derived from siderite at 500 °C (H500) still favored the conversion of NO. When the reaction temperature was lower than 350 °C, H500 favored the conversion of NO even in the presence of an alkali metal (K). The experimental data demonstrated the positive effect of siderite-derived α-Fe₂O₃ in SCR technology and provided insight into NO behavior in coaling flue gas after NH₃ injection.
显示更多 [+] 显示较少 [-]