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Relationship embedding and environmental governance performance research of pollution in a mining area, China Texte intégral
2020
Mi, Jun | Bian, Jie | Liu, Yaru | Guo, Wenxia
The aim of this study was to explore the enterprises in the mining area, in the face of environmental pollution, to use relationship embedding to acquire new key knowledge from the external network, and to improve environmental governance performance. In this paper, a model between relationship embedding and environmental governance performance was established, and five main hypotheses were proposed. Luliang Mountain Area is a typical mining area in China. And this study used 310 sample datum and regression analysis to empirically test the mechanism, taking Luliang Mountain Area as an example. First, SPSS statistical software was used for reliability and validity analysis of the questionnaire, and the results showed good. Then regression analysis was performed to test the hypothesis. The results showed that relationship embedding has a significant positive impact on environmental governance performance, and enterprises in the mining area use relationship embedding to obtain key knowledge, which can enhance environmental governance performance. Internal social capital has a positive adjustment effect on the relationship between relationship embedding and knowledge acquisition. In order to control environmental pollution in the mining area, enterprises should make full use of the relationship embedding, acquire new key knowledge, improve environmental governance capacity, and improve the environmental governance performance of enterprises.
Afficher plus [+] Moins [-]Utilizing waste corn-cob in biosynthesis of noble metallic nanoparticles for antibacterial effect and catalytic degradation of contaminants Texte intégral
2020
Đoàn, Văn Đạt | Luc, Van-Sieu | Nguyễn, Thị Lan Hương | Nguyễn, Thị Dung | Bảo, Định Giang
In the present study, cost-effective, and environmentally friendly fabrication of silver and gold nanoparticles was performed by using aqueous extract of waste corn-cob. The formation of the metallic nanoparticles (MNPs) was optimized by UV–Vis method. The phytoconstituents were responsible for reduction of silver and gold ions to silver nanoparticles (CC-AgNPs) and gold nanoparticles (CC-AuNPs) which were demonstrated by Fourier-transform infrared (FTIR) spectroscopy while formation of AgCl was attributed to the presence of chloride ions in the aqueous extract. The crystalline nature of the AgNPs, AgCl, and AuNPs was confirmed using the X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. Morphological studies showed that the synthesized CC-AgNPs existed in spherical shape with the size ranging from 2 to 28 nm possessing an average value of 11 nm while CC-AuNPs were present in the multiple shapes with size ranging from 5 to 50 nm possessing an average value of 35 nm. For studies on bioactive application, the CC-AgNPs exhibited a high antibacterial activity against three bacterial strains including Salmonella typhimurium, Bacillus cereus, and Staphylococcus aureus. In addition, the catalytic efficiency of MNPs was investigated for reduction of o-, m-, p-nitrophenols, and degradation of organic dyes including Eosin Y and Rhodamine 6G. The rate constants calculated from the kinetical data revealed that the biosynthesized nanoparticles are excellent catalysts in potential applications for treatment of wastewater. Graphical abstract .
Afficher plus [+] Moins [-]Determination of acute oral toxicity of glyphosate isopropylamine salt in rats Texte intégral
2020
Turkmen, Ruhi | Dogan, Ilkay
In this study, we aim to determine the median lethal dose (LD₅₀) of glyphosate isopropylamine salt (GI), which is commonly used in the world and especially in Turkey against to weeds, in male and female rats by using the probit or logit analysis method. A total of 140 Wistar rats were used, including 70 females and 70 males. To determine LD₅₀, the male and female rats were randomized into 7 groups made up of 10 animals in each group. At doses of 6000, 6500, 7000, 7500, 8000, 8500, and 9000 mg / kg, GI was administered to the male and female rats by oral gavage. After dosing, the animals were periodically monitored for 14 days. No deaths were observed after 48 h of herbicide application. In this study, only logit analysis was used for the LD₅₀ value to be calculated in the male rats within 24 h, while other analyses were carried out with the probit method. In the female and male rats, the LD₅₀ levels of GI between 24 and 48 h were determined as 7444.26–7878.50 mg/kg and 7203.58–7397.25 mg/kg, respectively. According to these results, it was concluded that female rats are more sensitive to GI than male rats. We believe that the findings that were obtained will guide researchers, clinicians, and toxicologists through preventive and curative studies against acute poisoning that may occur with GI.
Afficher plus [+] Moins [-]Bifenthrin exerts proatherogenic effects via arterial accumulation of native and oxidized LDL in rats: the beneficial role of vitamin E and selenium Texte intégral
2020
Feriani, Anouar | Hachani, Rafik | Tir, Meriam | Ghazouani, Lakhdar | Mufti, Afoua | Borgi, Mohamed Ali | Allagui, Mohamed Salah
The purpose of this study was to investigate, for the first time, the effects of Bifenthrin (Bif) chronic exposure on plasmatic and aortic lipid parameters disturbance and their pro-atherogenic possibility in Wistar rats. The ameliorative role of vitamin E (Vit E) and selenium (Se) were also targeted. Thus, rats were treated by gastric gavage with combination of Vit E (100 mg/kg/bw) and Se (0.25 mg/kg/bw) in alone and co-treated groups for 90 days. Apart from control and Vit E-Se groups, all the groups were subjected to Bif (3 mg/kg, via gavage) toxicity. Results showed that Bif increased markedly plasmatic and aortic total cholesterol, LDL-cholesterol, native LDL-apoB-100, and oxidized-LDL, compared to the control. Moreover, Bif treatment significantly increased the plasmatic levels of the pro-inflammatory cytokines TNF-α, IL-2, and IL-6. In addition, the densitometric quantification of protein bands showed that the amount of hepatic native LDL-receptor protein decreased significantly in the intoxicated rats compared to the control group. The expression of arterial LDL receptors (LDLRs) and scavenger receptors (CD36) was amplified owing to Bif toxicity. This harmful effect was confirmed by histological study using Oil-Red-O staining. Owing to their antioxidant capacities, Vit E and Se have maintained all the changes in plasma and aorta lipids and prevented the pro-atherogenic effect observed in Bif-treated animals.
Afficher plus [+] Moins [-]Application of oxidation-reduction potential (ORP) as a controlling parameter during the synthesis of Fe3O4@PVA nanocomposites from industrial waste (raffinate) Texte intégral
2020
Rezazadeh, Laleh | Sharafi, Shahriar | Schaffie, Mahin | Ranjbar, Mohammad
The objective of this study was to develop a process for the synthesis of magnetite nanocomposites from raffinate of hydrometallurgical plants containing iron ions. Towards this goal, a three-step process was developed. After the reduction of Fe(III) to Fe(II) in the first stage, Al³⁺ in the raffinate was precipitated as Al(OH)₃ and finally magnetite NPs were synthesized by chemical co-precipitation method via controlling the oxidation-reduction potentials (ORPs). The produced nanomaterials were analyzed using XRD, TEM, VSM, TGA, and FTIR. The TG, XPS, and FTIR results affirmed the existence of PVA while TEM images illustrated the spherical nanoparticles with an average size of about 19 ± 4 nm. Evaluation of VSM data indicated the highly ferromagnetic behavior for Fe₃O₄ and Fe₃O₄@PVA products at the room temperature with a saturation magnetization of 46.98 and 35.78 emu/g, respectively.
Afficher plus [+] Moins [-]Identifying and evaluating school environmental health indicators Texte intégral
2020
Lin, Shao | Lu, Yi | Lin, Ziqiang | Romeiko, Xiaobo Xue | Marks, Tia | Zhang, Wangjian | Khwaja, Haider A. | Dong, Guanghui | Thurston, George
Children’s health, attendance, and academic performance may be affected by school environmental hazards. While prior studies evaluated home environment and health, few have evaluated indicators of school in-/outdoor environment and health. This study addresses this knowledge gap by systematically reviewing and evaluating outdoor and indoor indicators of school environment and student’s health and performance in New York State (NYS). We also evaluate statistical methodologies to address highly correlated indicators and integrate multiple exposures. Multiple school environmental indicators were identified from various existing NYS datasets. We summarized data sources, completeness, geographic and temporal coverage, and data quality for each indicator. Each indicator was evaluated by scientific basis/relevance, analytic soundness/feasibility, and interpretation/utility, and validated using objective NYS data. Finally, advanced variable selection methods were described and discussed. We have identified and evaluated multiple school environmental health indicators. It was found that mold and moisture problems, ventilation problems, ambient ozone, and PM₂.₅ levels are among the top priorities of school environmental issues/indicators in NYS, which were also consistent while using NYS data. Choice of best variable selection method should be made based on the research questions and data characteristics. The school environmental health indicators identified, and variable selection methods evaluated, in this study could be used by other researchers to help school officials and policy makers initiate prevention programs.
Afficher plus [+] Moins [-]Relationship between oil price volatility and military expenditures in GCC countries Texte intégral
2020
Erdoğan, Seyfettin | Çevik, Emrah İsmail | Gedikli, Ayfer
Natural resource-rich countries transfer more sources to military expenditures due to extreme security concerns. As public revenues have declined due to the decline in oil prices, military expenditures have been cut in many countries. Nevertheless, this is not valid for all countries. Even in some countries, despite the decrease in oil prices and volatility, military expenditures increase. The aim of this study is to investigate the relationship between volatility in oil prices and military expenditures in GCC countries (United Arab Emirates, Bahrain, Qatar, Kuwait, Saudi Arabia, and Oman). The analysis period was determined differently for each country depending on the availability of data. UAE and Qatar were excluded from the analysis as the defense expenditures data of these countries could not be provided regularly. ARDL model was preferred for the research. According to the bound test results, there is a cointegration relationship between the variables in all countries. Besides, the long-term results showed that the volatility in oil prices in all countries, except for Bahrain, positively affects military expenditures. The error correction model indicated that there is a reverse relationship between oil price volatility and military expenditures. These findings indicated that despite the volatility in oil prices, military expenditures in GCC countries are not reduced.
Afficher plus [+] Moins [-]Effects of nitrite graded doses on hepatotoxicity and nephrotoxicity, histopathological alterations, and activation of apoptosis in adult rats Texte intégral
2020
El-Nabarawy, Nagla A. | Gouda, Ahmed S. | Khattab, Mohamed A. | Rashed, Laila A.
Nitrites are found in several forms; they are widely found in water resources and used as additives and preservatives for food and as a color source. We investigated the hazardous effects of exposing rats to different doses of nitrites. Moreover, we examined such impacts, after acute ingestion, on liver and renal tissues in rats and to what extent this affects the organs’ functions. Animals were divided into five groups: one control group 1 (group C) and four sodium nitrite (NaNO₂)–treated group (8 rats per group). The four NaNO₂-treated groups include group 2 (N20), group 3 (N40), group 4 (N60), and group 5 (N75). NaNO₂ was dissolved in distilled water, and single acute dose was orally given by gavage at 20, 40, 60, and 75 mg/kg body weight, respectively. Our results revealed significant increase of liver enzymes activity—aspartate transaminase (AST), alanine aminotransferase (ALT), and creatinine between different groups with increasing doses of nitrite ingestion. The results of hepatic and renal oxidative stress showed significant increase in the malondialdehyde (MDA) levels and significant decrease in the antioxidant parameters, such as reduced glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT), as the dose of nitrite increases. Further, the methemoglobin percent showed significant increase with increasing nitrite doses. Abnormal morphological alterations in the liver and kidney tissues were obviously proportional to the administered nitrite doses. The expression of caspase 3 and Bax level showed enhanced induction of immunoexpression, especially in the high doses of nitrites. On the other hand, the maximal immunoexpression level of anti-apoptotic marker Bcl₂ was found in lower doses of nitrites, whereas marked decrease of Bcl₂ levels was observed in the higher doses. In conclusion, administration of sodium nitrite in a dose-dependent manner is capable of inducing cellular and genetic toxicities and causes disturbance in biochemical analysis, oxidative and anti-oxidative balance, and methemoglobinemia. It also makes histopathological alterations and leads to the activation of apoptosis-related Bax, Bcl₂, and caspase 3 genes of liver and kidney tissues in rats.
Afficher plus [+] Moins [-]Thermodynamic study of the acid-induced decontamination of waste green sand generated in a brass foundry Texte intégral
2020
Sawai, Hikaru | Rahman, Ismail M. M. | Jii, Naoyuki | Egawa, Yuji | Mizutani, Satoshi | Hasegawa, Hiroshi
Waste foundry sand (WFS) from the brass and bronze casting and molding process include various potentially toxic elements (PTEs), such as copper, zinc, tin, and lead. Hence, the utilization of WFS in construction and geotechnical applications evokes environmental concerns due to the rain-induced leaching of PTEs into the groundwater system. The present study investigated the extractive decontamination of WFS using mineral acids, e.g., HCl, H₂SO₄, or HNO₃. Favorable extraction efficiency was achieved with HCl as compared to the other mineral acids, which was further enhanced at high temperatures and increased acid concentrations. The thermodynamic analysis indicated that ≥ 4 mol L⁻¹ of HCl and ≤ 100 °C temperature ensured maximum extraction of PTEs due to the endothermic interactions between the HCl and PTEs. The HCl-treated WFS needed to be rinsed with water to restrict the after treatment elution of PTEs. The hazardous environmental impact of acid-treated WFS was evaluated following the standard leaching test and comparison with legislative recommendations for PTEs, which showed the water-assisted leaching rate of all the PTEs are within the regulatory limits.
Afficher plus [+] Moins [-]Effects of soil heavy metal pollution on microbial activities and community diversity in different land use types in mining areas Texte intégral
2020
Zhao, Xingqing | Sun, Yu | Huang, Jian | Wang, Hui | Tang, Ding
Microbial activities and community structures play crucial roles in the soil environment and can be served as effective indicators to assess the ecological influence of heavy metal pollution in soil. This article selected soil samples from five land use types (mining area, mineral processing area, heap mining area, tailing area, and vegetable area) in the Shizishan mining area in Tongling, Anhui Province, China. The physicochemical properties, pollution characteristics, enzyme activities (catalase, urease, alkaline phosphatase, neutral phosphatase, cellulase, and sucrase), microbial biomass carbon (MBC), basal respiration (SBR), and metabolic entropy (qCO₂) in soil were determined and compared, and the relationship between environmental factors and the microbial activities and community diversity was analyzed. The results showed that, according to the Nemerow’s Pollution Index (PN), the values were the heap mining area (24.47) > mineral processing area (12.55) > mining area (9.81) > tailings area (6.02) > vegetable area (4.51). With the increase of heavy metal contamination in the sampling area, the six enzyme activities, MBC and SBR decreased, but the qCO₂ increased. Principal coordinate analysis (PCoA) and canonical correlation analysis (CCA) showed that the land use types, soil moisture content (MC), heavy metal content, pH, MBC, SBR, and qCO₂ were significantly affected by the microbial community. The most dominant phyla were Proteobacteria (34.73%), Bacteroidetes (9.25%), Acidobacteria (8.99%), and Chloroflexi (8.68%) at the phylum (0.01) level by a total of 18 phyla. It was also found that Firmicutes and Phormidium were more tolerant to heavy metals. These results contributed to an insight into key environmental variables shaping the microbial activities, community structure, and diversity under various land use types in mining area.
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