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The performance of micro-meso-pore HY zeolite for supporting Mo toward oxidation of dibenzothiophene Full text
2020
Dadashi, Mohaddese | Mazloom, Golshan | Akbari, Azam | Banisharif, Farhad
A uniformly distribution of 3 wt.% Mo (with tetrahedral coordination) on a commercial HY zeolite having both micro- and meso-pores, provided a new active catalyst which resulted 100% removal of DBT in this work. Respectively, H₂O₂ and acetonitrile were used as the oxidant and extraction solvent for oxidative desulfurization (ODS) at a mild condition. The structure of three-dimensional meso-pores, despite major micro-pores, was proved to be intriguing for the use of acidic HY zeolite as a support material in this process. The catalyst samples were characterized by different analyses of XRPD, XRF, FTIR, SEM, EDX, TEM, N₂ adsorption desorption, BET, BJH, UV-vis, and NH₃-TPD. High amounts of Mo were not in favor of the catalytic performance because of increasing non-framework polymolybdate formation, which led to decreasing meso-pore volume. Acid sites strength also decreased by increasing Mo content. The Mo active sites at a low loading of 3 wt.% reached the best performance for the complete removal of DBT (t = 90 min, T = 60 °C, catalyst/fuel = 8 g/L, O/S = 2, VSₒₗᵥₑₙₜ/VOᵢₗ = 1/2, DBT = 1000 ppm), mainly due to the presence of isolated Mo species in the framework of HY. The efficiency still reached to 90% after recycling the catalyst three times. The reusability of catalyst revealed the adsorption of the aqueous phase by this hydrophilic catalyst during the process being as a major deactivation factor. This was significantly diminished via a subsequent washing by acetonitrile.
Show more [+] Less [-]Optimizing reaction conditions and experimental studies of selective catalytic reduction of NO by CO over supported SBA-15 catalyst Full text
2020
Souza, Monique S. | Araújo, Rinaldo S. | Oliveira, Alcineia C.
Selective catalytic reduction of NO with CO (CO-SCR) was investigated based on optimizing the operating conditions by response surface methodology (RSM) and by appropriately choosing the supported SBA-15 catalysts. The effects of the CO-SCR reaction parameters such as NO:CO molar ratios and oxygen concentrations on the catalytic performance were determined by RSM to evaluate the NO conversion using a first-order polynomial model. The CuO/SBA-15 and Fe₂O₃/SBA-15 catalysts were synthesized by a hydrothermal method and characterized by X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), N₂ adsorption-desorption (BET), scanning electron microscopy coupled to energy dispersive X-Ray spectroscopy (SEM-EDS), and Fourier transform infrared spectroscopy (FTIR) to investigate the physicochemical properties of the solids. The RSM showed a very good agreement between predicted values and experimental results with the Pareto analysis confirming the accuracy and reliability of the model. The optimized results indicated the maximum NO conversion at 500 °C with using the NO to CO molar ratio of 1:2 (500:1000 ppm) in the absence of oxygen. Under these conditions, CuO/SBA-15 catalyst achieved 99.7% of NO conversion, whereas Fe₂O₃/SBA-15 had 98.1% of the catalytic parameter. Catalytic tests in CO-SCR reaction were performed on both catalysts at optimum operating conditions with CuO/SBA-15 exhibiting better performance compared to that of Fe₂O₃/SBA-15. The results revealed that CuO/SBA-15 was a promising catalyst for CO-SCR of NO due to the well-dispersed CuO phase on SBA-15 surface that allows the solid being more tolerant to the presence of oxygen.
Show more [+] Less [-]Toxicological potential of penconazole on early embryogenesis of white mice Mus musculus in either pre- or post-implantation exposure Full text
2020
El-Shershaby, Abd El-Fattah M. | Lashein, Fakhr El-Din M. | Seleem, Amin A. | Ahmed, Abeer A.
The present investigation was conducted to evaluate the effect of penconazole (PEN) fungicide on early embryogenesis of white mice. In the first experiment, 48 pregnant females were divided into different groups; the first group is control (G1). The second group (G2) was treated daily with PEN (30-, 20-, 10-, 5-mg/kg BW). The third group (G3) was treated with PEN (5-mg/kg BW; day after the other day). The fourth group (G4) was treated with PEN (2.5-mg/kg BW daily) during pre-implantation stage (from the 1st to the 4th day of gestation). The fifth group (G5) was treated with PEN (2.5-mg/kg BW daily) during post-implantation (from the 5th to the 8th day of gestation). The pregnant females were sacrificed at the 14th day of gestation. In the second experiment, 63 pregnant females were classified into control, PEN-treated during pre-implantation period (2.5-mg/kg BW), and PEN-administered during post-implantation period (2.5-mg/kg BW). Each group was sacrificed at stages E6.5, E7.5, E8.5, E9.5, E11.5, E14.5, and E18.5. The high doses of PEN in the first experiment showed failed pregnancy, foetoresorption, and embryo disorganization. High doses of PEN induce alterations in the uterus tissue at the level of histology and immunohistochemistry for the expression of TGFβ2, TNFR2, Caspase 10, and HSP70. The low doses of PEN in the second experiment showed upregulated expression of TGFβ2, TNFR2, Caspase 10, and HSP70 at stages E6.5 and E7.5. In conclusion, PEN was found to alter the suitable uterine environment for proper implantation and development at the levels of histological and immunohistochemical that could create a risk during the full course of embryogenesis.
Show more [+] Less [-]Argyrophilic nucleolar organizer regions in oral mucosa cells of crack and cocaine users: a cross-sectional study Full text
2020
Góes Rabelo, Rosângela | Salgueiro, Arthur Pias | Visioli, Fernanda | da Silva, Viviane Palmeira | das Graças Alonso Oliveira, Maria | Ribeiro, Daniel Araki | Cury, Patricia Ramos | dos Santos, Jean Nunes
The objective of this study was to analyze and compare the presence of argyrophilic nucleolar organizer regions (AgNORs) in exfoliated cells obtained from the buccal mucosa among crack and cocaine users and non-users by the AgNOR staining technique. Seventy-three males ≥ 18 years were categorized into two groups: 38 crack and/or cocaine users and 35 non-user volunteers. They were interviewed and responded a questionnaire regarding general health and drug addiction. Exfoliative cytology specimens were collected from the clinically intact buccal mucosa, and cytological preparations were fixed and stained by AgNOR technique. The mean number of AgNORs (p = 0.02) and the percentage of epithelial cells with more than 3 (p = 0.01) and 4 (p = 0.04) AgNORs/nucleus were significantly higher in the non-user group. In conclusion, the frequency and diversity of substances present in the drugs—cocaine, crack, and alcohol—consumed by the volunteers of this study may have influenced the number of AgNORs and the response to damage and consequent effect on protein synthesis.
Show more [+] Less [-]Biological activity and safety profile of monoterpenes against Plutella xylostella L. (Lepidoptera: Plutellidae) Full text
2020
Cai, Yuehong | Hu, Xian | Wang, Pan | Xie, Yongjian | Lin, Zhufeng | Zhang, Zhilin
Plutella xylostella L. is a cosmopolitan pest of wild and cultivated crucifer vegetables worldwide. It has developed resistance to almost all commercial chemicals, making them one of the most problematic field pests in China. The natural plant extracts and essential oils (EOs) could be a safe alternative for agricultural pests. The development and production of EOs decrease the negative effects of synthetic chemicals. In the present study, the fumigation activity of 8 pure monoterpenes against P. xylostella was evaluated. Results from fumigation tests revealed that 8 tested compounds exhibited various degrees of toxicity against adults of the diamondback moth. Cuminaldehyde was the most toxic compound based on the 12-h LC₅₀ (0.17 mg/L) and 24-h LC₅₀ (0.12 mg/L) values, respectively. Also for larvae and eggs, cuminaldehyde was the most toxic compound. The 12-h LC₅₀ value for cuminaldehyde to 1st, 2nd, and 3rd instar larvae was 0.10 mg/L, 0.12 mg/L, and 0.55 mg/L, respectively. The 24-h LC₅₀ value for the different instar larvae was 0.07 mg/L, 0.09 mg/L, and 0.35 mg/L, respectively. The 24-h LC₅₀ value for eggs (endpoint hatching rate) was 1.95 mg/L for cuminaldehyde, followed by carvacrol and eugenol (2.05 mg/L and 2.31 mg/L, respectively). Cuminaldehyde was very friendly to the larvae and adults of Harmonia axyridis and did not cause any mortality. Our results indicated that cuminaldehyde had potential insecticidal activity against P. xylostella and could be utilized in the novel biological pesticide development.
Show more [+] Less [-]Urinary paraben concentrations and their implications for human exposure in Iranian pregnant women Full text
2020
Hajizadeh, Yaghoub | Kiani Feizabadi, Ghasem | Ebrahimpour, Karim | Shoshtari-Yeganeh, Bahareh | Fadaei, Saeid | Darvishmotevalli, Mohammad | Karimi, Hossein
Parabens are widely used as preservatives in cosmetics, medicines, and foods due to its antimicrobial properties. Concerns have been raised regarding the estrogenic activity and potential endocrine disruption effects of parabens. Studies on monitoring of paraben exposure in the Iranian population are very scarce. This study was carried out to measure urinary concentrations of parabens, to estimate their daily intake, and to identify some of the sociodemographic factors affecting exposure to these compounds. The concentrations of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) were measured in urine samples collected from 95 Iranian pregnant women by gas chromatography mass spectrometry. The highest median concentration was 87.0 μg/L for MP, followed by PP, EP, and BP with median concentrations of 15.6, 9.64, and 8.57 μg/L, respectively. Except BP, the urinary concentrations of other parabens were comparable to those in other countries. Also, the highest daily intake was related to MP (median = 16.5 μg/kg-BW/day), which is less than the acceptable daily intake (ADI). A significant positive correlation was observed between the measured parabens. Significant negative associations were observed between age and BP, BMI and EP as well as parity and PP. On the other hand, income and smoking were significantly positively associated with MP, BP and EP, BP, respectively. The urinary MP and BP concentrations were higher among the subjects with diploma education (P = 0.003 and P = 0.006, respectively), and during the spring, urinary MP concentration was higher than other seasons. The results showed that Iranian pregnant women are more prone to parabens and their urinary paraben concentrations are associated with sociodemographic factors. This result could serve as a basis for evaluating the rate of exposure of the Iranian population to parabens in future studies.
Show more [+] Less [-]Stakeholders’ perspective on strategies to promote contaminated site remediation and brownfield redevelopment in developing countries: empirical evidence from Pakistan Full text
2020
Ahmad, Naveed | Zhu, Yuming | Shao, Jing | Lin, Hongli
Due to the potential of reducing negative outcomes of brownfields on environment and contribution to urban sustainability, brownfield redevelopment (BR) gained considerable recognition in the more recent era. Comprehensive literature shows that many studies proposed strategies to promote BR in developed nations; however, studies focusing on developing economies are scarce. Therefore, this study intends to identify significant strategies to promote BR in developing countries by taking the case of Pakistan. A comprehensive literature review and expert opinion were commenced to identify potential strategies. Data were collected from the main stakeholders involved in BR process through an empirical questionnaire. The findings revealed that “Low-interest loans and subsidies with the collaboration of government and financial institutions,” “Standardized definition, guidelines, and simplified brownfield process,” “Development of technical and infrastructure support,” “Create investors interest,” “Strengthening remediation technologies R&D” were the five most important strategies to promote BR in Pakistan. Theoretically, the novelty of the current study is to highlight the key strategies to promote BR in developing countries. Practically, the study facilitates governments, urban policymakers, environmentalists, and stakeholders to propose and implement appropriate strategies for promoting BR. Future studies can consider modeling the interactions between strategies and their impact on BR adoption.
Show more [+] Less [-]Year-to-year climate variability affects methane emission from paddy fields under irrigated conditions Full text
2020
Sun, Huifeng | Zhou, Sheng | Zhang, Jining | Zhang, Xianxian | Wang, Cong
A field experiment in Yangtze River delta of China was conducted to investigate the effects of four treatments (conventional chemical fertilizers (CF), chemical fertilizers incorporated with wheat straw (CF-WS), slow-release urea fertilizer incorporated with wheat straw (SCF-WS), and no fertilizers (Non-F)) on methane emission, rice grain yield, and straw biomass in three (2013, 2014, and 2015) consecutive growing seasons. Similar air temperature and precipitation were recorded in 2014 and 2015 normal seasons; however, the 2013 season with a 2.1–2.3 °C higher mean air temperature and a 61–64% lower precipitation than the normal seasons was considered as a warm-and-dry season.No significant differences in seasonal total methane emissions across all treatments were observed in 2014 and 2015 seasons. Seasonal total methane emissions were 58–294% higher in 2013 season compared to 2014 and 2015 seasons, which suggests that higher ambient temperatures increase methane emissions from paddy fields. The enhanced methane emission was seen mainly during the mid-to-late growth stages after mid-season drainage. CF-WS and SCF-WS significantly increased methane emissions before mid-season drainage relative to CF, and thereby enhanced methane emissions in both normal and warm-and-dry seasons in a seasonal scale.While rice grain yield in each treatment in 2013 season was close to or lower than that in 2014 and 2015 seasons, straw biomass in CF, CF-WS, and SCF-WS in 2013 season were significantly higher than those in 2014 and 2015 seasons, by both 29%, 33–41%, and 15–16%, respectively. Enhancements in methane emissions at higher air temperatures were significantly correlated to its greater straw biomass. Furthermore, combination of slow-release urea fertilizer and straw by ploughing can significantly increase above-ground biomass yields and nitrogen use efficiency in both normal and warm-and-dry seasons.
Show more [+] Less [-]The effect of environmental regulation on capacity utilization in China’s manufacturing industry Full text
2020
Cheng, Zhonghua | Liu, Jun | Li, Lianshui | Gu, Xinbei
How environmental regulations are used to improve manufacturing capacity is crucial to the future development of China’s manufacturing industry from a quality point of view. This paper adopts a dynamic spatial panel model to empirically analyze both the effects of different types of environmental regulation policies on capacity utilization in China’s manufacturing industry and their mechanisms. The results show that China’s manufacturing capacity utilization varies a great deal, with improvements in technical efficiency playing the main role, although with significant regional differences. Both command-and-control and market-incentive environmental regulation are conducive to improvements in manufacturing capacity utilization; market-incentive environmental regulation, however, plays the stronger role. The above mechanisms have certain differences though. Both types of environmental regulations are able to improve manufacturing capacity utilization by improving technical efficiency and equipment utilization but the command-and-control policy tool exerts a greater effect in improving technical efficiency while the market-incentive mechanism has a greater effect in improving equipment utilization.
Show more [+] Less [-]Performance evaluation of conventional and hybrid woven fabrics for the development of sustainable personal protective clothing Full text
2020
Memon, Arshad Hussain | Peerzada, Mazhar Hussain | Brohi, Khan Muhammad | Memon, Sheeraz Ahmed | Mangi, Sajjad Ali
This study examines the performance level of hybrid woven protective clothing (HWPC), manufactured from Kevlar® (K) and Ramie (R) yarns. The weave structures (plain, twill 1/3) and variables fiber ratios were used to produce HWPC. The performance level of HWPC was measured according to EN 388:2016. We came to the conclusion that blade cut resistance of plain and twill structure sustained protection level up to increase of KR 80:20 and KR 70:30, respectively; puncture resistance of K100% and HWPC remained in the same level of protection for plain and twill weaves; Abrasion resistance of K100% and HWPC of plain and twill weaves samples presented abrasive performance of same protection level, but the average number of cycles sustained for twill weave samples was slightly higher than plain weave. However, comparing the plain and twill weaves sample for tear resistance, twill weave samples have higher tear resistance than plain weave. A gray relational analysis and Taguchi method was performed to optimize the performance of two structures with variable fiber ratios. It was established that the article produced with K&R yarns with KR 80:20 ratio and twill weave presented the best performance against all test runs. The main objective of this study is to reduce plastic pollution by reducing the amount of synthetic fiber proportion in personal protective clothing and thereby reducing the dependence on nonrenewable sources for synthetic fiber. The 41 g/m² reduction of Kevlar® fiber has been made in a conventional PC with ramie fiber, without compromising the protection level. This will enhance the sustainability of HWPC.
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