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Improving environmental protection of waterborne polyurethane coating by adding TiO2/polyaniline/HNT/CNT nanocomposite Full text
2020
Nosrati, Rahimeh | Kiani, Gholamreza | Karimzad Ghavidel, Ayub | Rashīdī, ʻAlī
Nanostructures of titanium dioxide, polyaniline, halloysite, and carbon nanotubes have an excellent effect to improve environmental protection and surface properties of coatings like anticorrosion and self-cleaning attributes. In this research, we studied the individual effect of adding each nanostructure within the polyurethane matrix and also all nanostructure combinations with each other on the mentioned properties. To reach this aim, the polyurethane nanocomposites were prepared; then, anticorrosion and self-cleaning tests were carried out on the samples. FTIR spectroscopy and FESEM images were used to characterize the nanocomposite additives and coating influence. According to the obtained results, the polyurethane coating modified with titanium dioxide/polyaniline/halloysite nanotube/carbon nanotube nanocomposite showed very higher corrosion potential and resistance and lower corrosion current in the comparison with other coatings. Also, the mentioned polyurethane nanocomposite coating showed good hydrophilicity and it decolorized a dye contaminant with high efficiency which makes them appropriate candidate for the protection of the substrate against environmental destructive factors.
Show more [+] Less [-]Exposure to arsenic and lead in children from Salamanca México, effects on telomeric lengthening and mitochondrial DNA Full text
2020
Alegría Torres, Jorge Alejandro | Pérez Rodríguez, Rebeca Yasmín | García Torres, Lizeth | Costilla Salazar, Rogelio | Rocha-Amador, Diana
Levels of urinary arsenic and levels of lead in blood were measured in children attending elementary schools located in an industrial zone in Salamanca, México. Its possible effects using telomere length and mitochondrial DNA copy number as biomarkers of genomic disequilibrium by oxidative stress were studied. Eighty-eight children (6–15 years old) were included and urine samples were collected for quantification of arsenic, while lead was measured in blood samples using inductively coupled plasma mass spectrometry (ICP-MS). DNA was isolated from peripheral blood and relative telomere length and the mitochondrial DNA copy number were determined by real-time PCR. The geometric mean of urinary arsenic was 54.16 μg/L (11.7–141.1 μg/L). Ninety-eight percent of the children were above 15 μg/L (biomonitoring equivalent value). With respect to the concentration of lead in blood, the mean was 3.78 μg/dL (LOD-22.61), where 24.5% of the participants had equal or above the reference value (5 μg/dL; Mexican Official Norm NOM-199-SSA1–2000, 2017). A positive association between urinary arsenic and telomere length was found (β = 0.161; 95% CI: 0.12; 0.301; P = 0.034), while lead blood concentrations were negatively associated with mitochondrial DNA copy number (β = − 0.198; 95% CI: − 2.81; − 0.17; P = 0.019), after adjusting by age, sex, and total white blood cell count. Differences in the mitochondrial DNA content were observed in children with lead blood levels from 2.5 μg/dL, (P ≤ 0.001), suggesting an effect at lead exposure levels considered acceptable (< 5 μg/dL). In conclusion, children living in an industrial area in Salamanca showed an exposure to arsenic and lead and an impact on telomere length and mitochondrial DNA content associated with arsenic and lead exposure, respectively.
Show more [+] Less [-]Carbon inequality in the transportation industry: empirical evidence from China Full text
2020
Du, Qiang | Li, Jingtao | Li, Yi | Huang, Ning | Zhou, Jie | Li, Zhe
Transportation has significantly contributed to carbon emissions, and concerns regarding emissions mitigation have become central research issues. To avoid a reversal of the reduction convergence in the environmental field, mitigation strategies should aim to reduce the environmental risks posed by carbon inequality. This article uses the Gini index and Theil index to examine carbon inequality in the transport sector in China and decomposes the per capita carbon inequality using Kaya factors. Then, the variations within and between regions are analyzed by decomposing the Theil index of the carbon intensity by region. Our major findings are as follows. First, carbon inequality is relatively insignificant in the regional transport sector in China. Second, the main drivers of the per capita carbon inequality include the carbon intensity and per capita added value in the transport sector. Third, intra-regional components are major contributors to the heterogeneous spatial distribution of the carbon intensity, and the degree of carbon inequality in the eastern region is much greater than that in other regions. Moreover, the four economic regional components of the Theil index of the carbon intensity have had an obvious convergence effect since 2009. In addition, this study provides some suggestions for developing differentiated mitigation policies in different regions.
Show more [+] Less [-]Assessment on the effectiveness of environmental regulation in China—evidence from a panel data analysis Full text
2020
Lai, Xiaodong | Liu, Zhiming | Luo, Sumei
In the context of global warming and environmental deterioration, the environment impact assessment is a crucial institutional guaranty to assure less or no pollution during the process of the economic growth and rapid social development. This paper selected the environmental regulation system in China as a research target and assesses the effectiveness of green tax on the environment through an empirical analysis. The panel data from 2005 to 2015 in different cities in China are employed to analyze with a two-way fixed regression model; it analyzes the impact of environmental instruments like resource tax, excise tax, vehicle purchase tax, and pollutant discharge fees on environmental pollution and finds that the modeling conditions with green tax reform can lead to higher effect on environmental pollutant constrain but is distributed differently among east, central, and west based on the empirical analysis in China. Moreover, resource tax has a significant effect in the east and midwest of China. The effectiveness of excise tax on integrated pollution is not statistically significant. Compared with the midwest, eastern China’s green tax had a much better performance on reducing environmental pollution. Pollutant discharge fees indicates a significant negative correlation to integrated pollution. The consumption of the other goods (like meat consumption) plays a mediating effect between vehicle purchase tax and integrated environmental pollution. In addition, the relevant policy recommendations are proposed against different tax types.
Show more [+] Less [-]Exploration of the critical factors influencing the water quality in two contrasting climatic regions Full text
2020
Kang, Gelin | Qiu, Yu | Wang, Qingxiu | Qi, Zuoda | Sun, Yuting | Wang, Yuqiu
Over the past few decades, rivers have become severely polluted as a result of receiving vast quantities of domestic and industrial wastewater. The identification of the major factors that influence water quality is crucial to understand the interactions of anthropogenic and natural factors and develop river restoration projects. In this study, the QUAL2Kw water quality model was used to quantitatively evaluate the most critical factors for water quality at two sites with different meteorological conditions and urban scales. The genetic algorithm (GA) was used to optimize the parameters in the model. The Monte Carlo simulation (MCS) method was used to assess the model uncertainty and sensitivity in all reaches for five water quality outputs (temperature, CBOD, DO, TP, and TN) in two seasons. The K-means clustering method associated with the sensitivity results was used to identify the major factors influencing the water quality in all reaches from the input data and the model parameters. The results showed that CBOD, TN, and TP were most sensitive to headwater and tributary quality. DO tended to be affected by more natural reactions than the other water quality indicators. In the cold and dry seasons and the more urbanized areas, river pollution was more severe, and the impact of natural reactions was reduced. The simulation results revealed the reliability of QUAL2Kw in modeling the quantity and quality of all river reaches. The method applied in this study is beneficial for the improvement and management of the water environment.
Show more [+] Less [-]Single or combined exposure to chlorpyrifos and cypermethrin provoke oxidative stress and downregulation in monoamine oxidase and acetylcholinesterase gene expression of the rat’s brain Full text
2020
Abd El-Moneim Ibrahim, Khairy | Mohamed Abdelrahman, Shimaa | K. A. Elhakim, Heba | Ali Ragab, Eman
The extensive uses of organophosphates and pyrethroids have made it necessary to investigate the neurotoxicity of their combination as they may implicate in the neurodegenerative syndromes. Monoamine oxidase-A (MAO-A) and acetylcholinesterase (AChE) gene expression in the rat brain were evaluated after independent and combined intoxications with chlorpyrifos and cypermethrin. Twenty-four mature male rats were equally distributed into four groups. The first one was kept as a control group, whereas the second, third and fourth were orally gavage with chlorpyrifos (16.324 mg/kg), cypermethrin (25.089 mg/kg) and their combination (9.254 mg/kg), respectively, for 4 weeks. As compared to the control group, intoxications with chlorpyrifos and/or cypermethrin revealed significant (P < 0.05) declines in the levels of brain neurotransmitters (dopamine and serotonin) plus the enzymatic activities of MAO-A, AChE and sodium-potassium adenosine triphosphatase. The mRNA genes expression of MAO-A and AChE have also confirmed the enzymatic actions. Moreover, the oxidative injury recorded as the levels of malondialdehyde and nitric oxide markedly increased (P < 0.01), while the total thiol content reduced and the histopathological outcomes have confirmed these impacts. In conclusion, chlorpyrifos and cypermethrin revealed antagonistic inhibitions on the brain MAO-A and AChE gene regulation through neurotransmission deteriorations and oxidative damage, which could describe their contributions in the neuropathological progressions.
Show more [+] Less [-]Water consumption assessment in Asian chemical industries supply chains based on input–output analysis and one-way analysis of variance Full text
2020
Shafiei, Mahboobe | Moosavirad, Seyed Hamed | Azimifard, Arezoo | Biglari, Shirin
Chemical sector contributes extensively to the economic development of countries, however, it is one of the main water-consuming industries. Considering that the corporate water accounting along complete SCs can help companies in improving their sustainable water managements along their value chains, this paper aims to study the water consumption in the entire supply chain of the chemical industry from a multi-regional input-output perspective. In this regard, six Asian countries including Indonesia, Taiwan, China, Japan, South Korea and India are selected to be studied based upon the availability of their data. In the following, the direct water consumed by themselves and the indirect water used by their suppliers are measured for each country using input-output analysis method. Moreover, to draw on the conclusions of selected Asian countries, the amount of consumed water in their supply chains is compared with each other using one-way analysis of variance method. The results from input-output analysis show that the indirect water consumption in the chemical SCs of Indonesia, China, India and South Korea are 20.66, 4.62, 1.37 and 1.08 times greater than their direct water use, while the indirect water consumption for Japan and Taiwan are 0.73 and 0.13 times less than their direct values. The final results from one-way analysis of variance indicate that direct and indirect amount of water consumptions in the chemical supply chains of the selected countries do not follow the same trend over 15 years. However, India and China are the top two countries in terms of both direct and indirect amounts of water consumption due to their higher population. This study presents valuable information for authorities and policymakers in terms of proper water consumption management in chemical industry and other industrial sectors. In this matter, technology-based or production-related actions are beneficiary for affecting direct water use, while consumption-based or end-use actions are more appropriate for affecting indirect water consumption.
Show more [+] Less [-]Effect of mobile phone radiation on oxidative stress, inflammatory response, and contextual fear memory in Wistar rat Full text
2020
Singh, Kumari Vandana | Gautam, Rohit | Meena, Ramovtar | Nirala, Jay Prakash | Jha, Sushil Kumar | Rajamani, Paulraj
In the present lifestyle, we are continuously exposed to radiofrequency electromagnetic field (RF-EMF) radiation generated mainly by mobile phones (MP). Among other organs, our brain and hippocampus in specific, is the region where effect of any environmental perturbation is most pronounced. So, this study was aimed to examine changes in major parameters (oxidative stress, level of pro-inflammatory cytokines (PICs), hypothalamic-pituitary-adrenal (HPA) axis hormones, and contextual fear conditioning) which are linked to hippocampus directly or indirectly, upon exposure to mobile phone radiofrequency electromagnetic field (MP-RF-EMF) radiation. Exposure was performed on young adult male Wistar rats for 16 weeks continuously (2 h/day) with MP-RF-EMF radiation having frequency, power density, and specific absorption rate (SAR) of 1966.1 MHz, 4.0 mW/cm², and 0.36 W/kg, respectively. Another set of animals kept in similar conditions without any radiation exposure serves as control. Towards the end of exposure period, animals were tested for fear memory and then euthanized to measure hippocampal oxidative stress, level of circulatory PICs, and stress hormones. We observed significant increase in hippocampal oxidative stress (p < 0.05) and elevated level of circulatory PICs viz. IL-1beta (p < 0.01), IL-6 (p < 0.05), and TNF-alpha (p < 0.001) in experimental animals upon exposure to MP-RF-EMF radiation. Adrenal gland weight (p < 0.001) and level of stress hormones viz. adrenocorticotropic hormone (ACTH) (p < 0.01) and corticosterone (CORT) (p < 0.05) were also found to increase significantly in MP-RF-EMF radiation-exposed animals as compared with control. However, alteration in contextual fear memory was not significant enough. In conclusion, current study shows that chronic exposure to MP-RF-EMF radiation emitted from mobile phones may induce oxidative stress, inflammatory response, and HPA axis deregulation. However, changes in hippocampal functionality depend on the complex interplay of several opposing factors that got affected upon MP-RF-EMF exposure.
Show more [+] Less [-]Distribution of uranium and thorium chains radionuclides in different fractions of phosphogypsum grains Full text
2020
Szajerski, Piotr
This work presents results obtained using gamma spectrometry measurements of phosphogypsum samples on a non-fractionated (native) and fractionated phosphogypsum byproduct. The phosphogypsum was divided into particles size fractions within the range of < 0.063, 0.063–0.090, 0.090–0.125, 0.125–0.250, and over 0.250 mm and analyzed after reaching radioactive equilibrium using high-resolution gamma spectrometry technique. It was found that there is no significant differentiation between ²²⁶Ra distribution among particular grain size fractions of this material; however, tendency for preferential retention of radionuclides in particular grain size fractions is observed. The detailed analysis of results revealed that radium is preferentially retained in smaller grain size fractions, whereas lead and thorium in coarse fractions. The results indicate that overall ²²⁶Ra activity concentrations between particular fractions of phosphogypsum vary globally between − 34 and + 47% regarding non-fractionated material, and for ²¹⁰Pb activity concentration, fluctuations are found between − 26 up and + 38%. Presumably, the mechanism of radium incorporation into gypsum phase is based on a sequence of radium bearing sulfate phases formation followed by a surface adsorption of these phases on the calcium sulfate crystals, whereas for lead and thorium ions, rather incorporation into crystal lattice should be expected as more likelihood process.
Show more [+] Less [-]Synergistic effect of Cordia curassavica Jacq. essential oils association against the phytopathogen Xanthomonas campestris pv. campestris Full text
2020
Da Silva, Rafael Salomão | De Oliveira, Mayara Mendes Gonçalves | Silva, Kleiton Paulo | Da Silva Vasconcelos Rodrigues, Isabela | Dos Santos Pinto, Vanderson | Blank, Arie Fitzgerald | Fernandes, Roberta Pereira Miranda
The increased use of pesticides applied to treat diseases caused by bacteria has caused serious environmental problems. There are few fungicides/bactericides for the treatment of plant diseases caused by Xanthomonas campestris pv. campestris (Xcc), and only two natural products with general bactericidal/fungicidal use are available on the market. Thus, this study evaluated the antimicrobial activity of essential oils (EOs), and their combinations, from five distinct genotypes of Cordia curassavica (Jacq.) Roem. & Schult (Syn. Varronia curassavica Jacq.) (CCUR) against Xcc. GC/MS chemical analysis revealed α-pinene, sabinene, (E)-caryophyllene, ar-curcumene, β-sesquiphellandrene, 7-cyclodecen-1-one, and ar-Turmerone as the major compounds of the five EOs of CCUR. All EOs showed growth inhibition of Xcc with minimum inhibitory concentration between 500 and 1000 μg mL⁻¹. The associations between two EOs from different CCUR genotypes showed that 70% of the total combinations had an additive effect. However, the combinations between CCUR-002 × (-302, -202) and CCUR-302 × (-601) showed a synergistic effect, with mean fractional inhibitory concentration FIC₅₀ values of 0.28, 0.42, and 0.40, respectively. This study demonstrates that combinations of C. curassavica EOs have antimicrobial activity and a potential to be used in the control of black rot. Graphical abstract
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