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Результаты 3311-3320 из 5,014
Multi-core-shell composite SnO2NPs@ZIF-8: potential antiviral agent and effective photocatalyst for waste-water treatment Полный текст
2019
Chandra, Ramesh | Singh, Vedita | Tomar, Shailly | Nath, Mala
With increasing environment pollution and bacterial transmitted viral diseases globally, the development of new, effective, and low-cost materials/strategies is the current major challenge. To combat with this alarming problem, three new multi-functional and thermally stable SnO₂NPs@ZIF-8 composites (NC1, NC2, and NC3) were synthesized by a facile and sustainable approach involving in situ encapsulation of SnO₂NPs (150, 300, and 500 μL suspension in methanol) within zeolitic imidazole framework at room temperature. The morphology and crystallinity of ZIF-8 remained unchanged upon the proper encapsulation of SnO₂NPs in its matrix. Herein, for the first time, the antiviral potential of ZIF-8 and SnO₂NPs@ZIF-8 against chikungunya virus is reported by investigating their cytotoxicity against Vero cell line (employing MTT ((3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide)) assay). The maximum non-toxic doses were 0.04 mg mL⁻¹ for ZIF-8 and SnO₂NPs@ZIF-8 and 0.1 mg mL⁻¹ for SnO₂NPs. Further, NC1 exhibited (based on plaque assay) reduction in viral load/titers up to > 80% during post-treatment and > 50% during pre-treatment, greater than that of ZIF-8 and SnO₂NPs due to synergistic effect. Further, NC1 (10 mg) exhibited enhanced photocatalytic efficiency (≥ 96%) for degradation of methylene blue (0.5 × 10⁻⁵ M) at pH ˃ 7.0. The probable mechanism for their antiviral activity and photocatalytic activity has been discussed. The multi-functional composites can effectively be used to reduce water pollution and as remedy for mosquito/bacterial transmitted viral diseases.
Показать больше [+] Меньше [-]Fresh underground light non-aqueous liquid (LNAPL) pollution source zone monitoring in an outdoor experiment using cross-hole electrical resistivity tomography Полный текст
2019
Shao, Shuai | Guo, Xiujun | Gao, Chang
Real-time monitoring of source zone of light non-aqueous liquids (LNAPLs) is important for preventing accidental pollution and taking effective underground pollution remediation measures. As a high-precision monitoring technology, cross-hole electrical resistivity tomography (CHERT) has been widely used to obtain static information regarding underground stratigraphic structures and dynamic information regarding fluid motion. The time-lapse data processing method can be used to obtain pollution zone dynamic change information. Since the leakage rate directly affects the diffusion range of pollution, this study simulated the initial evolution process of LNAPL pollution source regions under two different leakage rates. The time-lapse monitoring of the above process was performed using CHERT. The test results show that CHERT can be used to observe the migration of LNAPLs and the initial evolution of the contaminated area. Differences in leakage rate will result in variation in soil wettability and fluid distribution, which will cause changes in soil resistivity in the corresponding region. The low-saturation LNAPL-contaminated area may exhibit low-resistivity characteristics and is easily overlooked in field investigations. In addition, the degree of contamination in the saturated zone can be quantitatively evaluated by CHERT; however, the pollution range and oil saturation value determined by CHERT are underestimated. The results showed the electrical variation characteristics of the initial evolution process of the fresh pollution source area and provide data that will enable early warnings of LNAPL leakage. This shows that CHERT is a promising tool for monitoring LNAPL pollution source leakage even if further research is needed to fully understand the effect of hydrological processes on electronic signals.
Показать больше [+] Меньше [-]Allocating on coal consumption and CO2 emission from fair and efficient perspective: empirical analysis on provincial panel data of China Полный текст
2019
Wang, Bang-jun | Zhao, Jia-lu | Wu, Yan-fang | Zhu, Chao-qun | He, Yin-nan | Wei, Yi-xi
This paper considers a problem of how to allocate resource effectively and equitably among provinces. To address the problem, a total factor resource input-oriented data envelopment analysis (DEA) model is used to evaluate the energy and environmental efficiency for 30 provinces in China during 2009–2013 in this paper. Based on the evaluation results, from efficient and fair perspective, a revised DEA-based resource allocation model is established. It is worth pointing out that the model takes the input orientation and output orientation into account at the same time and can be used to allocate coal consumption and carbon emission by 2020 for 30 provinces in China. Results indicate that if the Chinese government wants to fulfill the CO₂ emission reduction targets of 40–45% by 2020, and coal consumption intensity reduction target during 13th Five-Year Plan, inefficient provinces will undertake more coal consumption and carbon emission intensity reduction obligation share. And provinces with historical high coal consumption and high CO₂ emission intensity will have greater potential of coal consumption and carbon emission intensity reduction. In addition, this paper set several scenarios of gross domestic product (GDP) growth rate, under the scenarios analysis, finds the growth rate of GDP has negative effect on reduction of coal consumption and carbon dioxide emissions intensity. This research provides more realistic practical significance for achieving sustainable economic development.
Показать больше [+] Меньше [-]Systematic review and meta-analysis on the association between phthalates exposure and insulin resistance Полный текст
2019
Shoshtari-Yeganeh, Bahareh | Zarean, Maryam | Mansourian, Marjan | Riahi, Roya | Poursafa, Parinaz | Teiri, Hakimeh | Rafiei, Nasim | Dehdashti, Bahare | Kelishadi, Roya
This study aims to provide an overview of human studies on the association of exposure to phthalates and insulin resistance. We systematically searched human studies available until 15 January 2018.We conducted a literature search in Scopus, ISI Web of Science, PubMed, Google Scholar, and Cochrane Collaboration. We used the following keywords to identify relevant articles: “phthalate”, “phthalate ester”, “metabolic syndrome”, “insulin resistance”, “glucose intolerance”, and “diabetes”. For analyzing data, we conducted meta-analysis using the Stata software. We appraised each study to examine the sources of heterogeneity, including difference in clinical outcomes and exposure measurements. To determine the robustness and whether some of the factors have the highest impact on the results of the present meta-analysis, several sensitivity analyses were conducted. Sensitivity analysis showed that by removing studies with the highest weight and age groups, no change was observed in heterogeneity. Moreover, with excluding the study conducted in Europe, the results remained unchanged and constant. In addition, the funnel plot and Egger’s tests were executed to access publication bias. Both the funnel plots and Egger’s test did not show any evidence of publication bias (P = 0.31). In the random effects meta-analysis of all studies (n = 8), the pooled correlation coefficient between phthalate exposure and HOMA-IR was 0.10 (95% CI; 0.07–0.12, P < 0.001), with significant heterogeneity (P < 0.001, I² = 85.5%). Our findings revealed positive association between exposure to phthalate metabolites and increased HOMA-IR; this association remained significant even after adjusting the analysis for multiple confounding variables.
Показать больше [+] Меньше [-]Modelling aggregate exposure to pesticides from dietary and crop spray sources in UK residents Полный текст
2019
Kennedy, Marc C. | Garthwaite, David G. | de Boer, Waldo J. | Kruisselbrink, Johannes W.
Human exposure to pesticide mixtures can occur from the diet and other sources. Realistic exposure and risk assessments should include multiple sources and compounds and include the relative hazards of the different compounds. The EU-funded Euromix project is developing new web-based tools to facilitate these calculations. A case study is presented that exemplifies their use for a population of UK residents, including exposure from crop-spraying. A UK pesticide usage survey provided information on real pesticide combinations applied to crops of wheat, potatoes, sugar beet and dessert apples. This information was combined with outputs from two alternative simulation models of spray drift to estimate dermal, oral and inhalation exposures of residents. These non-dietary exposures were combined with dietary exposure estimates using the Monte Carlo Risk Assessment software to produce a distribution of aggregated and cumulative exposures. Compounds are weighted by relative potency to generate a measure of overall risk. Uncertainty quantification was also included in the distribution of exposures. These tools are flexible to allow diverse sources of exposure and can provide important information to decision-makers and help to prioritise testing of pesticide mixtures. Including non-dietary sources changed the prioritisation of pesticide mixtures, when compared to dietary exposure alone.
Показать больше [+] Меньше [-]Economic growth, financial development, and trade in nexuses of CO2 emissions for Southeast Asia Полный текст
2019
Naushīn, Miṣbāḥ | Iqbāl, Jāvīd | Hassan, Syeda Anam
In energy economics literature, we found few studies on the association between environmental quality energy consumption and financial development. The current study is an attempt to contribute in literature by examining the link between carbon dioxide (CO₂) emissions, financial development, energy consumption, and economic growth, in South East Asian economies for the period 1980–2017 using annual time series data. For empirical analysis, Bound tests for cointegration and error correction approach are used. The estimated results confirm that financial development has positive impact on environmental quality. On the other hand, in the long run, the rise in energy consumption economic growth and trade openness is unfavorable for environment quality. Our results confirm U-shaped relationship between economic growth and environmental quality that is a proof of environmental Kuznets curve (EKC). Additionally, the government needs to design different modes of energy consumption to solve the problem of environmental degradation. Moreover, the major conclusion extends new insight for authority to make a comprehensive trade and financial policies to improve environmental quality.
Показать больше [+] Меньше [-]Hepatoprotective effects of curcumin and taurine against bisphenol A-induced liver injury in rats Полный текст
2019
Uzunhisarcikli, Meltem | Aslanturk, Ayse
Bisphenol A (BPA) is an estrogenic endocrine disrupting chemical to which humans are frequently exposed during routine daily life. Curcumin and taurine are natural products that have also been used as antioxidants against different environmental toxin–induced hepatotoxicity. Furthermore, they have protective and therapeutic effects against various diseases. The present investigation has been conducted to evaluate the therapeutic potential of curcumin (100 mg kg⁻¹) and taurine (100 mg kg⁻¹) for their hepatoprotective efficacy against BPA (130 mg kg⁻¹)-induced liver injury in rat. BPA significantly elevated the levels of malondialdehyde (MDA), while it reduced the activities of catalase (CAT), total glutathione S-transferase (GST), total glutathione peroxidase (GPx), and total superoxide dismutase (SOD). Besides, these biochemical changes were accompanied by histopathological alterations marked by the destruction of normal liver structure. The histological examinations showed that exposure of BPA caused dilatation of sinusoids, inflammatory cell infiltration, congestion, and necrosis in liver parenchyma. The BPA-induced histopathological alterations in liver were minimized by curcumin and taurine treatment. Furthermore, no necrosis was observed in the liver tissues of curcumin plus BPA and taurine plus BPA-treated rats. Oral administration of curcumin and taurine to BPA-exposed rats significantly reversed the content of lipid peroxidation products, as well as enhanced the activities of GPx and GST, CAT, and SOD enzymes. These findings have indicated that curcumin and taurine might have a protective effect against BPA-induced hepatotoxicity in rats.
Показать больше [+] Меньше [-]Tree diversity, biomass and carbon storage in sacred groves of Central India Полный текст
2019
Dar, Javid Ahmad | Subashree, Kothandaraman | Raha, Debojyoti | Ashwani Kumar, | Khare, Pramod Kumar | Khan, Mohammed Latif
Sacred groves are small or large patches of forest and are rich in biodiversity, store carbon (C) in biomass and soil, besides providing important ecosystem services. However, the information on tree species diversity, biomass, and C storage in sacred groves of Central India, Madhya Pradesh is elusive and fragmented. In the present study, 41 sacred groves were inventoried for tree species diversity, biomass, and C storage in vegetation and soil. A total of 103 tree species from 81 genera belonging to 37 families were recorded. Shannon’s diversity, Dominance, Fisher’s alpha, and species evenness indices for trees varied: 0.77–2.53, 0.07–0.64, 1.58–20.37, and 0.28–0.90 respectively. Tree density ranged 75–675 no. of stems ha⁻¹ with a mean of 271 no. of stems ha⁻¹, while basal area ranged 6.8–47 m² ha⁻¹ with a mean value of 27 m² ha⁻¹. Tree biomass ranged 34.9–409.8 Mg ha⁻¹ with a mean value of 194.01 Mg ha⁻¹, while, tree C ranged between 17.5 and 204.9 Mg C ha⁻¹ with a mean value of 97.0 Mg C ha⁻¹. The total soil organic carbon stock (0–30 cm) ranged from 22.4 to 112.5 Mg C ha⁻¹ with the mean value of 62 Mg C ha⁻¹. Biomass C and SOC contributed 61% and 39% of the total C stocks, respectively. Tree C stock showed a significant positive relationship with tree basal area (R² = 0.968). A total of five tree species belonging to four families were found to be vulnerable in Central India. The present study reveals that the sacred groves of Central India are species rich, have higher C stocks and sequestration potential in both vegetation and soil, and calls for an immediate attention for conservation and planning for long-term C sequestration.
Показать больше [+] Меньше [-]Antioxidant-oxidant balance and vital parameter alterations in an eukaryotic system induced by aflatoxin B2 exposure Полный текст
2019
Çavuşoğlu, Kültiğin | Yalçin, Emine
This study was performed to evaluate the toxic effects of aflatoxin B₂ (AFB₂) on antioxidant-oxidant balance and vital parameters such as physiological, cytogenetic, and anatomical alterations in Allium cepa L. root tip cells. Toxic effects of AFB₂ on vital parameters were investigated by using the changes in weight gain, germination percentage, chromosomal aberrations (CAs), mitotic index (MI), micronucleus frequency (MN), and anatomical structure. Malondialdehyde (MDA) and reduced glutathion (GSH) levels and superoxide dismutase (SOD) and catalase (CAT) activities in root cells were investigated as antioxidant-oxidant parameters. For this aim, A. cepa bulbs were seperated into five groups as negative control, positive control, and AFB₂ treatment groups. In results, while the rate of germination percentage, weight gain, and MI rates decreased, MN and CA frequency increased in AFB₂-treated groups compared with the negative control. Most common CAs observed in AFB₂-treated groups were fragment and chromosome bridges. It was determined that in 160 μg L⁻¹ AFB₂-treated group there was a 70.8% increase in MDA and a 78.1% decrease in GSH level compared with the negative control group and these changes indicate oxidative damage. In 160 μg L⁻¹ AFB₂ treatment group, SOD and CAT activities decreased importantly due to inhibition. In anatomical examinations, it was determined that AFB₂ treatment caused some anatomical damages in A. cepa root cells such as necrosis, cell deformation, and thickening in cell wall. This study showed that AFB₂, which has the least data among aflatoxins, causes serious in vivo toxic effects in A. cepa root cells.
Показать больше [+] Меньше [-]Spent pot liner from aluminum industry: genotoxic and mutagenic action on human leukocytes Полный текст
2019
Andrade-Vieira, Larissa Fonseca | Trento, Marcus Vinícius Cardoso | César, Pedro Henrique Souza | Marcussi, Silvana
Spent pot liner (SPL) is a toxic solid waste generated in the aluminum mining and processing industry. SPL is considered as an environmental pollution agent when is dumped on environment. Thus, it is important to access its toxicological risk for the exposed organisms. The comet assay and micronucleus test are efficient tests to detect genotoxic/mutagenic compounds by DNA damage observation. Therefore, in the present study, the genotoxic potential of SPL was evaluated through the micronucleus and comet assay on human leukocytes. After ethics committee approval (COEP—UFLA n°. CAAE 11355312.8.0000.5060), blood aliquots collected from healthy volunteers were exposed to increasing concentrations of SPL (from 0.1 to 80 g L⁻¹). All SPL treatments, including the lowest concentration applied (0.1 g L⁻¹), significantly increased the micronucleus frequency. The frequency of DNA damage was determined by visual scores (from 0 to 4) and the results were expressed on percentage of damage and arbitrary units (AU). CaCl₂ (0.01 M) was applied as negative control (NC) and doxorubicin (10 μg mL⁻¹) as positive control (PC). It was observed a dose-dependency between SPL treatments: as SPL concentration for cell incubation increases, the frequency of damage on DNA also increases. Cells incubated on the NC presented nucleoids class 0 to 2, while those exposed to SPL presents nucleoids class 0 to 4. SPL-incubated cells increasing significantly the frequency of nucleoids class 4. For the PC, the UA of damage was 267.74, which is lower than the one observed for the treatments with high doses of SPL (40–287.40 g L⁻¹ and 80–315.30 g L⁻¹). Thus, it was demonstrated that the SPL is a genotoxic agent that induces DNA damage on exposed organisms.
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