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Biomimetic detoxifier Prunus cerasifera Ehrh. silver nanoparticles: innate green bullets for morbific pathogens and persistent pollutants Полный текст
2020
Jaffri, Shaan Bibi | Ahmad, Khuram Shahzad
Silver nanoparticles were fabricated in the presence and absence of light with silver nitrate and aqueous extract of Prunus cerasifera leaf via facile and one-pot green method. P. cerasifera leaf extract reduced and stabilized the nanoparticles with phytometabolites expunging the need for addition of external reducing agents. Optimized silver nanoparticle syntheses was done with variations in leaf extract concentration, time, temperature, and molarity for deciphering the photocatalytic, antifungal, and antibacterial potential of synthesized nanoparticles. Optical, compositional, and morphological analyses of the synthesized nanoparticles were done by UV-visible spectrometry (UV-Vis), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Formation of silver nanoparticles was confirmed firstly through UV-Vis by exhibition of peaks with 400–450 nm. FTIR confirmed the presence of major organic groups responsible for reduction of nanoparticles. AFM confirmed the spherical morphology of the synthesized nanoparticles with remarkable dispersion without any agglomeration. Phytochemical analysis for P. cerasifera leaf metabolites was done by GC-MS. Spherical nanoparticles having a size range of 57–144 nm were obtained with face-centered cubic crystals. The average crystallite size obtained from XRD spectra was 2.34 nm. Enhanced photocatalytic first-order kinetics were obtained for persistent organic pollutants, i.e., crystal violet, methylene blue, and malachite green (R² = 0.99, 0.99, 0.98) in less than 15 min. Biomedical and agricultural significance as an antibiotic drug and utilization as a fungicides substitute was explored against nine resistant microbes. Statistically significant variations were analyzed via one-way analysis of variance (ANOVA) and Kruskal-Wallis test and specific multi comparison tests. Active to highly active inhibition zones manifested the use of biogenic silver nanoparticles as potential candidate for applications in biological arenas and as environmental remediators.
Показать больше [+] Меньше [-]The role of financial development, tourism, and energy utilization in environmental deficit: evidence from 20 highest emitting economies Полный текст
2020
ʻUs̲mān, Muḥammad | Kousar, Rakhshanda | Makhdum, Muhammad Sohail Amjad
This study establishes a long-run relationship between ecological footprint, financial development, energy utilization, and tourism in 20 highest emitting economies under the environmental Kuznets curve (EKC) framework by utilizing the longitudinal data covering the period from 1995 to 2017. In the procedure of panel data estimation, conventional methodologies usually overlook the problem of cross-sectional dependence and heterogeneity across cross-sections. The other concern linked to the published literature is that only a small number of studies have estimated the effect of financial development and tourism on the environment in the presence of EKC framework simultaneously, even though these sectors have potentially substantial impact on environmental quality. To bridge these analyzed gaps, this study employs two different unit root tests: Cross-section Augmented Dickey Fuller (CADF) and Cross-section Augmented Im, Pesaran and Shin (CIPS) to confirm that the series are stationary at first difference after confirming the cross-sectional dependency. Westerlund cointegration test applied to confirm the long-run association among variables. Augmented mean group (AMG) results discovered that financial development and the energy utilization significantly enhance the pollution level, while tourism sector reduces the environmental deficit. Moreover, these findings do not validate the EKC hypothesis. Based on the empirical findings, multiple policy implications are suggested to control and reduce the environmental degradation without hindering economic growth and development for the underlying highest emitting countries.
Показать больше [+] Меньше [-]Stormwater runoff and pollution retention performances of permeable pavements and the effects of structural factors Полный текст
2020
Liu, Wen | Feng, Qi | Chen, Weiping | Deo, Ravinesh C.
Permeable pavements, as additive structures that have a good capability for runoff and pollutant reduction, are extensively used for sustainable urban drainage techniques. However, the exact mechanisms of runoff retention and pollutant reduction of a permeable pavement system remain unclear and so, it has become an ongoing issue and motivation for hydrologists and design and structural engineers. In this research paper, a suite of four scale-based runoff plots representing permeable pavements were designed with different permeable surface types and gravel layer thickness treatments, and coupled with simulated rainfall experiments to analyze the impacts of structural factors of permeable pavements on runoff retentions and pollution reduction. The present results showed that the average time to runoff for permeable pavements under low-intensity rainfall scenarios was approximately 78.5 min, while this was shortened to only 51.5 min under high-intensity rainfall scenarios. In terms of the average runoff retention of permeable pavements tested under low- and high-intensity rainfall cases, the results recorded approximately 52.5% and 42.5%, respectively, but runoff retention performances were relatively greater for the case of smaller storms within the scale experiments. Importantly, there was no statistical significance for the time to runoff and runoff retention between the permeable bricks and porous concretes for the analyzed rainfall events. The thicker gravel layers significantly delayed runoff generation and increased runoff retention percentages. Runoff pollutant load reduction rates of total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP) were varied between permeable bricks and porous concretes. Runoff pollutants load reduction rates of TSS, TN, and TP were highly enhanced while the gravel layer thickness increased from 10 to 20 cm. Higher TSS, TN, and TP pollutant load removals were found from the lower intensity rainfalls. These findings could promote understanding of the hydrologic properties of permeable pavements and help design engineers in optimizing their design of permeable pavements for better runoff retention and pollution removal.
Показать больше [+] Меньше [-]Evaluation of acute and chronic exposure to aflatoxin B1 in indigenous women of the Huasteca Potosina, Mexico Полный текст
2020
Díaz de León Martínez, Lorena | Rodríguez-Aguilar, Maribel | Wong-Arce, Alejandra | Díaz-Barriga, Fernando | Bañuelos Hernández, Bernardo | Rosales Mendoza, Sergio | Flores Ramírez, Rogelio
Aflatoxin B₁ (AFB₁) is one of the most studied mycotoxins due to its high occurrence in food and its hepatotoxic, immunosuppressive, carcinogenic, childhood growth, genotoxic, mutagenic, and teratogenic effects in humans and animals. Exposure to AFB₁ is reported to be both, acute and chronic; the main exposure pathway to AFB₁ is through the intake of contaminated food. In Mexico, although the reports of several studies addressing the problem of aflatoxins in maize and other foods, the evidence has been centered on exposure to AFB₁ and to the quantification of the Aflatoxins themselves, but there is null evidence about genotoxic effects of aflatoxins in vulnerable populations. Therefore, this study focused on assessing chronic AFB₁ exposure through the AFB₁-lys biomarker adduct and acute exposure through total AFB₁-DNA adducts in women from a rural indigenous community in the Huasteca Potosina (Mexico). A hundred percent of the studied population presented total AFB₁-DNA and AFB₁-lys adducts in concentrations of 1.08 (0.48–1.34) μmol of adduct/mol of DNA and 2.33 (1.08-102.6) pg/mg of albumin respectively (median (min-max)). Thus, continuous monitoring and important changes in regulations are desired and recommended. The results in this study provide enough evidence to support the toxic effects that the exposure to AFB₁ represents, as well as the population risk that it poses, and in the same sense, the current need to create an intervention program that directly influences the control of the sources of exposure in order to reduce it.
Показать больше [+] Меньше [-]The influence of consumers’ intention factors on willingness to pay for renewable energy: a structural equation modeling approach Полный текст
2020
Irfan, Muhammad | Zhao, Zhen-Yu | Li, Heng | Rehman, Abdul
As the adoption of renewable power generation technologies (RPTs) is a complex and multidimensional process influenced by a variety of factors, it provokes traction among researchers to identify these influencing factors. This study aims to investigate the impact of consumers’ intention factors on willingness to pay (WTP) for renewable energy (RE) in Pakistan. The current research has contributed through expanding the theoretical framework of the theory of planned behavior by adding two new constructs, i.e., belief about RE cost and environmental concern to better understand consumers’ intentions towards adoption or prohibition of RPTs. Findings are based on the primary data gathered from 349 residents in the five major cities of Pakistan including, Karachi, Lahore, Faisalabad, Rawalpindi, and Multan by conducting a comprehensive survey. Structural equation modeling was employed for data analysis purposes. Research results indicate that the influencing factors such as attitude, subjective norms, and perceived behavioral control positively moderate the relationship between consumer’s intention and WTP for RE, belief about RE cost has a negative effect, while environmental concern did not find to have a significant effect. Based on research findings, this study offered essential policy recommendations to fulfill the country’s energy needs on its way to a future of sustainable development.
Показать больше [+] Меньше [-]Comparative evaluation of biochemical methane potential of various types of Ugandan agricultural biomass following soaking aqueous ammonia pretreatment Полный текст
2020
Oliwit, Abura Tobby | Cayetano, Roent Dune A. | Kumar, Gopalakrishnan | Kim, Jun Seok | Kim, Sang-Hyoun
The feasibility of pretreatment involving soaking in aqueous ammonia (SAA) for the anaerobic digestion (AD) of eight different types of agricultural biomass of Ugandan origin was investigated. Moderate pretreatment temperatures of 60 and 90 °C were employed, and the NH₃ concentration, solid-to-liquid ratio, and pretreatment time were fixed at 15.0% (w/w), 1:6, and 6 h, respectively. The delignification efficiencies of the SAA pretreatment ranged from 51.1 to 76.6%, and the maximum value was observed for maize bran pretreated at 90 °C. Biochemical methane potential experiments proved that the breaking of the complex bonds of lignin made fermentable sugars easily accessible to microorganisms. In all cases, the SAA pretreatment enhanced the methane potential of the eight types of Ugandan biomass compared with its untreated counterparts. The pretreated maize bran exhibited the highest methane yield of 291.5 mL CH₄/g COD, which is 83.1% of the theoretical conversion. SAA followed by AD is useful for employing Ugandan agricultural biomass as a renewable energy source.
Показать больше [+] Меньше [-]Growth inhibition of Microcystis aeruginosa and adsorption of microcystin toxin by the yeast Aureobasidium pullulans, with no effect on microalgae Полный текст
2020
Mohamed, Zakaria A. | Alamri, Saad | Hashem, Mohamed | Mostafa, Yasser
This study evaluates the inhibitory effect of a yeast strain, Aureobasidium pullulans KKUY0701, isolated from decayed cyanobacterial bloom against harmful cyanobacterium Microcystis aeruginosa and determines the ability of this strain to remove microcystin (MC) toxin from the water. The antialgal activity of this yeast strain was assayed by co-cultivation with M. aeruginosa, diatom, and green algal species. The MC adsorption experiment was conducted in the presence of living and heat-inactivated yeast cells. Both yeast cells and filtrates caused a rapid reduction in the growth of M. aeruginosa, with complete death and cell lysis occurring after 3 days. The yeast strain did not exhibit any inhibitory effect on either green algae or diatoms. Both living and heat-inactivated yeast cells were capable of adsorption of MC on their surfaces. Inactivated yeast exhibited higher adsorption capacity and lower intensity than living yeast for the adsorption of MC toxin. The results of this study suggest that this yeast strain could be employed to selectively reduce cyanobacterial blooms in freshwaters. Moreover, the application of heat-inactivated yeast’s biomass for toxin adsorption gives new possibilities in drinking water treatment plants.
Показать больше [+] Меньше [-]Zinc oxide nanoparticles enhance expression of maspin in human breast cancer cells Полный текст
2020
Khorsandi, Layasadat | Farasat, Maryam
Toxic and apoptotic impacts of zinc oxide nanoparticle (ZNP) on different cancer cells have been reported. Maspin (a mammary serine protease inhibitor) as a tumor suppressor gene can inhibit tumor growth and metastasis. The expression of maspin is modulated by p53, Bcl-2 family genes, and estrogen receptor α (ER-α). This study aimed to assess the ZNP effects on maspin expression in MCF-7 cells (a breast cancer cell). Experimental groups (ZNP5, ZNP10, and ZNP20) received 5, 10, and 20 μM/mL ZNP for 48 h, respectively. 17-β-estradiol (E2) was used to evaluate the role of ER-α in the anticancer impact of ZNP. Cell viability, Annexin V, migration assay, gene expression, and western blotting methods were applied to evaluate ZNP effects on the MCF-7 cells. ZNP at the concentrations of 10 and 20 μM/mL could significantly decrease the viability and migration rate, and significantly increase apoptosis percentage in the MCF-7 cells. ZNP significantly enhanced mRNA expression and protein level of maspin in MCF-7 cells in a concentration-dependent way. ZNP concentration-dependently elevated mRNA expression and protein level of p53 and Bax while reduced the expression of Bcl-2 and ER-α. E2 promoted cancer cell growth by enhancing survival and migration rates. E2 treatment reduced mRNA expression and protein level of maspin and p53, and elevated Bcl-2 expression. ZNP considerably changed these events induced by E2 in the MCF-7 cells. It is concluded that the maspin overexpression is one of the toxic mechanisms of the ZNP on the ER-α-positive breast cancer cells, and can suppress the migration of these cells.
Показать больше [+] Меньше [-]Interaction between shadow economy and pollution: empirical analysis based on panel data of northeast China Полный текст
2020
Pang, Jingru | Mu, Hailin | Zhang, Ming
Side issues of economy development break out in China during recent decades, like environmental pollution or the widely ignored one, shadow economy. Using annual data for the three provinces at northeast China over the period 2000 to 2016, this paper examines the size of the shadow economy by MIMIC model first and then adopts the dynamic panel analysis to study the direct relationship between the shadow economy and pollution level. The major innovation point of this paper is the pioneering study of the impact from the pollution level on the size of shadow economy. We also employ various pollution descriptions from terrestrial, aquatic, and atmospheric ecosystems as the robustness check to make our following conclusions more comprehensive and credible: (1) shadow economy is a direct quality factor to the increase of the pollution level. (2) A positive effect from pollution to shadow economy also exists: the higher the pollution level is, the larger the size of shadow economy will be. In the end, this paper proposes several valuable information and suggestions to the government in economy development and pollution abatement.
Показать больше [+] Меньше [-]Moral extension of the protection motivation theory model to predict climate change mitigation behavioral intentions in Taiwan Полный текст
2020
Chen, Mei-Fang
In this study, perceived moral obligations were included in the protection motivation theory (PMT) model to explain people’s intentions to participate in climate change mitigation behaviors. Empirical data and structural equation modeling results of a nationwide cross-sectional survey in Taiwan confirmed the higher explanatory power of the moral extension PMT model than that of the original PMT model. As expected, threat and coping appraisal of climate change affect protection motivation. In addition, perceived moral obligation affects protection motivation. This protection motivation enhances the intention to participate in climate change mitigation behaviors. The mediation effect of protection motivation was also verified in the moral extension PMT model. Practical implications and suggestions are proposed for the government and related authorities as well as environmental groups to encourage people to participate in climate change mitigation behaviors.
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