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A new simple protocol for the synthesis of nanohybrid catalyst for oxidative desulfurization of dibenzothiophene Full text
2020
Ghahramaninezhad, Mahboube | Ahmadpour, Ali
This study offers an investigation of the catalytic activity of TiO₂/SiO₂ during oxidative desulfurization (ODS) of a model fuel that includes dibenzothiophene (DBT), using hydrogen peroxide (H₂O₂) as a green oxidant in the absence of UV irradiation. For the first time, though a novel and simple protocol, TiO₂/SiO₂ nanohybrid was synthesized using ascorbic acid and glycerol as green complexing and polymerizing agents, respectively. The TiO₂/SiO₂ catalyst was thoroughly characterized by XRD, FT-IR, nitrogen adsorption-desorption measurements, TEM, FESEM, and TGA. Results revealed a high catalytic oxidative activity for the catalyst in the removal of DBT regarding sulfur removal up to 99.4% within 20 min under optimum reaction conditions. The main factors affecting the ODS process, including catalyst dosage, temperature, O/S molar ratio, and different oxidizing agents, were evaluated to identify optimum conditions. The desulfurization efficiency of the recoverable catalysts showed no loss in activity after four times. The present article suggests a new and green method for the synthesis and characterization of an efficient catalyst (TiO₂/SiO₂) in deep oxidative desulfurization at 25 °C and removal of refractory organosulfur compounds that yield ultra-low sulfur fuels. Also, it proved to have a much higher catalytic oxidation capacity when compared to pure TiO₂.
Show more [+] Less [-]Elevated exposure to polycyclic aromatic hydrocarbons (PAHs) may trigger cancers in Pakistan: an environmental, occupational, and genetic perspective Full text
2020
Rehman, Muhammad Yasir Abdur | Taqi, Malik Mumtaz | Hucheina, Imarāna | Nasir, Jawad | Rizvi, Syed Hussain Haider | Syed, Jabir Hussain
Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic compounds which are emitted through incomplete combustion of organic materials, fossil fuels, consumption of processed meat, smoked food, and from various industrial activities. High molecular mass and mobility make PAHs widespread and lethal for human health. A cellular system in human detoxifies these toxicants through specialized enzymatic machinery called xenobiotic-metabolizing (CYP450) and phase-II (GSTs) enzymes (XMEs). These metabolizing enzymes include cytochromes P450 family (CYP1, CYP2), glutathione s-transferases, and ALDHs. Gene polymorphisms in XMEs encoding genes can compromise their metabolizing capacity to detoxify ingested carcinogens (PAHs etc.) that may lead to prolong and elevated exposure to ingested toxicants and may consequently lead to cancer. Moreover, PAHs can induce cancer through reprograming XMEs’ gene functions by altering their epigenetic markers. This review article discusses possible interplay between individual’s gene polymorphism in XMEs’ genes, their altered epigenetic markers, and exposure to PAHs in cancer susceptibility in Pakistan.
Show more [+] Less [-]The nexus between economic globalization and human development in Asian countries: an empirical investigation Full text
2020
Ulucak, Recep | Danish, | Li, Nan
In recent years, countries both developed and developing ones have experienced a rapid economic globalization expanding economic activities. Although this economic globalization process is fruitful for the economy; however, what role it plays in the promotion of the human development index is still unknown. To this end, the study tries to explore the linkage among economic globalization, real income, and human development index in Asian countries from 1990 to 2015. The advanced econometric techniques that allow dependencies across countries are employed. The panel cointegration approach, Westerlund (2007) panel cointegration test, confirms the cointegration relationship among study variables, and the study estimates long-run cointegration parameters. Results reveal that economic globalization has not a significant impact on human development. However, real income promotes human development in Asian countries.
Show more [+] Less [-]Development of agricultural waste/recycled plastic/waste oil bio-composite wallpaper based on two-phase dye and liquefaction filling technology Full text
2020
Xiao, Dingtian | Yu, Zhifeng | Qing, Shan | Du, Shunlin | Xiao, Huaqiang
In this paper, a complete biomass composite processing system based on agricultural waste powders, recycled plastics, and waste oil is proposed. The wood-colored wallpaper, the green wallpaper, and the blue wallpaper are produced by this processing system. These wallpapers are new products with low cost, high added value, and environmental friendliness. These wallpapers have also been systematically tested. Based on the analysis of test results, a 3D model of material formation mechanism, liquefaction filling technology, and hybrid network model construction technology are obtained. The experiment found the reasonable RLDPE and RLLDPE ratio (1:0.26), the reasonable ratio of biomass to specialty solvents (1:1.5), the reasonable dose of the solid dye (3%), and the reasonable concentration of dye solutions. Wood-colored bio-composite wallpaper products have a smooth surface, wood color (ΔE = 36.7), natural aroma, and good comprehensive mechanical properties (tensile strength 9.255 MPa; elongation at break 20.998%; Young’s modulus 2229.475 MPa). The processing system and wallpaper products in this article not only promote the plastic recycling economy and sustainable agricultural development but also provide new channels for the development of waste oil reuse and new ideas for the development of high value-added biocomposite materials.
Show more [+] Less [-]Energy recovery from waste printed circuit boards using microwave pyrolysis: product characteristics, reaction kinetics, and benefits Full text
2020
Huang, Yu-Fong | Lo, Shang-Lien
Energy recovery from waste printed circuit boards (PCBs) was carried out by using microwave pyrolysis. According to thermogravimetric analysis, the maximum weight loss rate of waste PCBs occurred at 323 °C. When waste PCBs was heated under microwave irradiation at 300 W, the temperature can be reached within 10 min. Compared with conventional pyrolysis, microwave pyrolysis can provide higher weight loss of waste PCBs by 3–5 wt%. Microwave pyrolysis is helpful for the delamination of waste PCBs. Almost 71% of the gaseous product can be directly used as a fuel or converted into other forms of energy. Microwave pyrolysis can produce more HBr than conventional pyrolysis by approximately 17%. The main components of liquid product were phenols and phenyls. The overall energy recovery from waste PCBs using microwave pyrolysis can be 62%. According to kinetic analysis, it would need 20 min of processing time to decompose the combustible fraction of waste PCBs at 300 W. The maximum processing capacity of the microwave pyrolysis system for waste PCBs can be 1.36 kg, with the energy production of 2710 kJ. Furthermore, the pyrolyzed PCBs can be further processed to recycle valuable metals. Therefore, microwave pyrolysis of waste PCBs can be a complete and effective circular economy system to create high energy and economic benefits.
Show more [+] Less [-]Evaluation of phytotoxicity, cytotoxicity, and genotoxicity of ZnO nanoparticles in Vicia faba Full text
2020
Youssef, Mohamed S. | Elamawi, Rabab M.
Due to the accelerating use of manufactured nanomaterials, more research is needed to define their impact on plants. The present investigation aimed at evaluating the effect of different levels (0.0, 10, 25, 50, and 100 mg/L) of ZnO nanoparticles (NPs) on Vicia faba during seed germination and seedling establishment. Additionally, V. faba root meristems were used as a model to monitor the cytotoxic and genotoxic effects resulting from exposure to ZnO NPs. The influence of ZnO NPs on three isoenzyme systems, peroxidase, α, and β esterase, was also evaluated using native-PAGE. Our results showed that lower concentrations of ZnO NPs (especially 10 and 25 mg/L) enhanced seed germination and improved seedling growth, while higher concentrations (100 and 200 mg/L) resulted in phytotoxicity. Cytological investigations of ZnO NPs-treated V. faba root cells denoted the clastogenic and aneugenic nature of ZnO NPs. Differential increase in mitotic index and significant alterations in cell cycle were observed upon exposure to ZnO NPs. High concentrations of ZnO NPs markedly induced chromosomal aberration, micronuclei, and vacuolated nuclei formation. Chromosomal breakage, chromosomal bridges, ring chromosomes, laggard chromosomes, and stickiness were also observed at a higher rate. The PAGE analysis showed that ZnO NPs treatments altered the expression patterns of all studied enzyme systems. Collectively, results from this work will help to further understand the phytotoxic effects of nanomaterials.
Show more [+] Less [-]Dengue fever awareness: effect of an educational intervention on nursing students, Tanta, Egypt Full text
2020
Aldeib, Abdelaziz F. | Saied, Shimaa M.
Dengue fever (DF) is one of the world’s most important vector-borne illnesses. In 2017, Egypt experienced a dengue outbreak. This study aimed to assess the knowledge and attitudes of nursing students regarding DF and the effectiveness of an education intervention to improve students’ knowledge and attitude. An intervention study was conducted among 4th year nursing students of Tanta Faculty of Nursing using a self-administered predesigned validated questionnaire before and after introducing an educational session. The main DF information sources were formal teaching, social networks, television, and physicians. Less than half of the students (45.5%) had “good” knowledge grade after the intervention compared with only 7.2% in the pre-test. The students’ knowledge and attitude improved after the application of the intervention session. The positive impact of the educational intervention on knowledge and attitude regarding DF and its prevention among the target group revealed the importance of the inclusion of teaching materials about DF into the students’ curricula.
Show more [+] Less [-]Exposure to arsenite and cadmium induces organotoxicity and miRNAs deregulation in male rats Full text
2020
Mumtaz, Farah | Albeltagy, Rasha S. | Diab, Marwa S. M. | Abdel Moneim, Ahmed E. | El-Habit, Ola H.
Sodium arsenite (NaAsO₂) and cadmium chloride (CdCl₂) are two prime examples of un-biodegradable compounds that accumulate in the ecosystems causing great threats to human health and produce severe adverse effects. However, their joint toxicities are poorly understood in mammals. This study aimed to identify the effect of exposure to NaAsO₂ (5 mg/kg, by oral gavage) and CdCl₂ (1 mg/kg injected interperitoneal, i.p.) either alone or in combinations after 14 and 28 days on oxidative stress, antioxidant enzyme activities, and histopathological changes. The results revealed a downregulation of miR-146a also, in miR-let7a after 14 days and a notable upregulation after 28 days. However, administrations of their combinations for 14 days caused downregulated miR-146a and miR-let7a. However, upregulation miR-let7a was observed only after 28 days. Organotoxicity of liver results in a remarkable increase in oxidative stress biomarkers by the two metals either alone or in combinations. A remarkable decrease was noted in an antioxidant enzyme activity indicating a defect in the antioxidant defense system. Also, CdCl₂ alone showed remarkable liver histopathological changes. This study concluded that there was a close relationship of high epigenetic changes as deregulation of both miR-146a and miR-let7a as a result of the joint toxicity of both compounds, and ultimately major changes in hepatic tissues that may lead to cell transformations. However, further studies are needed to investigate the target genes for those miRNAs.
Show more [+] Less [-]Prospect of phytoremediation combined with other approaches for remediation of heavy metal-polluted soils Full text
2020
Liu, Shuming | Yang, Bo | Liang, Yunshan | Xiao, Yunhua | Fang, Jun
Accumulation of heavy metals in agricultural soils due to human production activities—mining, fossil fuel combustion, and application of chemical fertilizers/pesticides—results in severe environmental pollution. As the transmission of heavy metals through the food chain and their accumulation pose a serious risk to human health and safety, there has been increasing attention in the investigation of heavy metal pollution and search for effective soil remediation technologies. Here, we summarized and discussed the basic principles, strengths and weaknesses, and limitations of common standalone approaches such as those based on physics, chemistry, and biology, emphasizing their incompatibility with large-scale applications. Moreover, we explained the effects, advantages, and disadvantages of the combinations of common single repair approaches. We highlighted the latest research advances and prospects in phytoremediation-chemical, phytoremediation-microbe, and phytoremediation-genetic engineering combined with remediation approaches by changing metal availability, improving plant tolerance, promoting plant growth, improving phytoextraction and phytostabilization, etc. We then explained the improved safety and applicability of phytoremediation combined with other repair approaches compared to common standalone approaches. Finally, we established a prospective research direction of phytoremediation combined with multi-technology repair strategy.
Show more [+] Less [-]An effective recycling direction of water-based drilling cuttings and phosphogypsum co-processing in road cushion layer Full text
2020
Li, Bing | Wei, Sha | Zhen, Yi-wen
The technology used in the production and exploration of shale gas creates a new source of clean energy. However, during the processes, large amounts of water-based drilling cuttings (WDC) are generated. Phosphogypsum (PG) is a by-product from the industry of phosphate fertilizer. Approximately, 5 tons of PG are generated for the production of per ton of phosphoric acid. The pile up of WDC and PG lead to severe risks of nearby soil and surface water. This paper paid attention to the recycling of WDC and PG as major raw materials in the preparation of construction cushion layer. In the research, physical properties, microstructure, and environmental pollution of the road cushion layer prepared from WDC and PG were investigated. The results show that the physical properties of compactness and unconfined compressive strength are basic meet the China national standard. The WDC cushion layer mainly constitutes of AFt, C-S-H, and plate-like Ca(OH)₂ around the mineral phases. The leaching test revealed that the contaminants in the layer do not exceed the limits allowed by the “National Overall Discharge Standard of Sewage” (GB 8978-1996). This paper therefore outlines the effects that provide an effective way for the utilization of WDC and PG.
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