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Resultados 4571-4580 de 4,924
Amelioration of titanium dioxide nanoparticle reprotoxicity by the antioxidants morin and rutin
2019
Hussein, Mohamed M. A. | Gad, Emad | Ahmed, Mona M. | Arisha, Ahmed H. | Mahdy, Hasnaa F. | Swelum, Ayman Abdel-Aziz | Tukur, Hammed A. | Saadeldin, Islam M.
The present study aimed to examine the ameliorative effects of morin and rutin on the reproductive toxicity induced by titanium dioxide nanoparticles (TiO₂NPs) in male rats. A total of seventy adult male Sprague-Dawley rats were randomly divided into seven groups, each comprising ten rats. Nanoreprotoxicity was induced by treating rats with TiO₂NPs at a dosage of 300 mg/kg body weight for 30 days. Morin (30 mg/kg body weight) and rutin (100 mg/kg body weight) were co-administered with or without TiO₂NPs to rats either individually or combined. Only distilled water was administered to the control group. The results showed that TiO₂NPs enhanced oxidative stress, indicated by reduced levels of antioxidants such as superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) in testicular tissues, and increased levels of the lipid peroxidation marker malondialdehyde (MDA). TiO₂NPs significantly reduced the levels of sex hormones (testosterone, FSH, and LH), reduced sperm motility, viability, and sperm cell count, and increased sperm abnormalities, in addition to damaging the testicular histological architecture. TiO₂NPs resulted in the downregulation of 17β-HSD and the upregulation of proapoptotic gene (Bax) transcripts in the testicular tissues. Conversely, morin and/or rutin had a protective effect on testicular tissue. They effectively counteracted TiO₂NP-induced oxidative damage and morphological injury in the testis by conserving the endogenous antioxidant mechanisms and scavenging free radicals. Thus, we suggest that morin and rutin could be used to alleviate the toxicity and oxidative damage associated with TiO₂NP intake.
Mostrar más [+] Menos [-]Comparison of extraction techniques for polycyclic aromatic hydrocarbons from lichen biomonitors
2019
Van der Wat, Leandri | Forbes, Patricia B. C.
Lichens are useful biomonitors for atmospheric polycyclic aromatic hydrocarbons (PAHs). Different sample preparation techniques were explored in this regard, including ultrasound-assisted solvent extraction, microwave-assisted extraction, Soxhlet, and the quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique. It was found that a QuEChERS technique using hexane:acetone (1:1, v/v), never reported before for application to lichens, provided the best recoveries of internal standards, the highest total peak area for all PAHs of interest, and %RSDs comparable with the other preparation techniques tested. The optimized sample preparation technique was found to be a comparatively fast method (45 min), with good recoveries (96%), using less solvents and minimal energy consumption. Strong matrix effects were found: both strong enhancement (for the lighter PAHs) and strong suppression (for the heavier PAHs). The use of matrix-matched standards is thus imperative for the accurate determination of PAH concentrations in the lichen samples. Graphical abstract “Note: This data is mandatory. Please provide.”
Mostrar más [+] Menos [-]Long-term pollutant removal performance and mitigation of rainwater quality deterioration with ceramsite and Cyperus alternifolius in mountainous cities of China
2019
Chai, Hongxiang | Chen, Zi | Shao, Zhiyu | Deng, Siping | Li, Liang | Xiang, Yu | Li, Li | Hu, Xuebin | He, Qiang
Rainwater harvesting brings various desired environmental and social benefits in urban development. Tanks in rainwater harvesting systems need low-maintenance and low-cost approaches to manage water quality, especially for scattered small rainwater tanks associated with complex terrains in mountainous cities. Four rain barrels were set up to store roof runoff at the campus of Chongqing University, Chongqing, China. Barrel 1 (B1) and barrel 2 (B2) stored the first-flush water and the roof runoff with first-flush water diverted, respectively, while barrel 3 (B3) was loaded with a biological ceramsite and barrel 4 (B4) used biological ceramsite as a substrate media and planted with Cyperus alternifolius (C. alternifolius) to treat the first-flush water. The performances of the rain barrels were evaluated as well as the variations in water quality parameters were examined. The removal efficiency of B3 was 48.2%, 76.0%, 44.3%, and 24.6% for COD, NH₄⁺–N, TN, and TP, respectively, while B4 had removal efficiencies of 93.4%, 71.0%, 75.0%, and 76.5% for COD, NH₄⁺–N, TN, and TP, respectively. B4 had BOD, NH₄⁺–N, TN, and TP concentrations within the class III Chinese Standard requirement after a storage period of about 240 days. Furthermore, the turbidity in B4 kept dropping. Thus, B4 is a more promising alternative for water quality management in mountainous cities of China.
Mostrar más [+] Menos [-]Linking nano-ZnO contamination to microbial community profiling in sanitary landfill simulations
2019
Akyol, Çağrı | Ozbayram, Emine Gozde | Demirel, Burak | Onay, Turgut Tüzün | Ince, Orhan | Ince, Bahar
Nanomaterials (NMs) commercially used for various activities mostly end up in landfills. Reduced biogas productions reported in landfill reactors create a need for more comprehensive research on these greatly-diverse microbial pools. In order to evaluate the impact of one of the most widely-used NMs, namely nano-zinc oxide (nano-ZnO), simulated bioreactor and conventional landfills were operated using real municipal solid waste (MSW) for 300 days with addition nano-ZnO. Leachate samples were taken at different phases and analyzed by 16S rRNA gene amplicon sequencing. The bacterial communities were distinctly characterized by Cloacamonaceae (phylum WWE1), Rhodocyclaceae (phylum Proteobacteria), Porphyromonadaceae (phylum Bacteroidetes), and Synergistaceae (phylum Synergistetes). The bacterial community in the bioreactors shifted at the end of the operation and was dominated by Rhodocyclaceae. There was not a major change in the bacterial community in the conventional reactors. The methanogenic archaeal diversity highly differed between the bioreactors and conventional reactors. The dominance of Methanomicrobiaceae was observed in the bioreactors during the peak methane-production period; however, their prominence shifted to WSA2 in the nano-ZnO-added bioreactor and to Methanocorpusculaceae in the control bioreactor towards the end. Methanocorpusculaceae was the most abundant family in both conventional control and nano-ZnO-containing reactors.
Mostrar más [+] Menos [-]Adsorption of pharmaceuticals from biologically treated municipal wastewater using paper mill sludge-based activated carbon
2019
Silva, Carla Patrícia | Jaria, Guilaine | Otero, Marta | Esteves, Valdemar I. | Calisto, Vânia
A waste-based alternative activated carbon (AAC) was produced from paper mill sludge under optimized conditions. Aiming its application in tertiary wastewater treatment, AAC was used for the removal of carbamazepine, sulfamethoxazole, and paroxetine from biologically treated municipal wastewater. Kinetic and equilibrium adsorption experiments were run under batch operation conditions. For comparison purposes, they were also performed in ultrapure water and using a high-performance commercial AC (CAC). Adsorption kinetics was fast for the three pharmaceuticals and similar onto AAC and CAC in either wastewater or ultrapure water. However, matrix effects were observed in the equilibrium results, being more remarkable for AAC. These effects were evidenced by Langmuir maximum adsorption capacities (qₘ, mg g⁻¹): for AAC, the lowest and highest qₘ were 194 ± 10 (SMX) and 287 ± 9 (PAR), in ultrapure water, and 47 ± 1 (SMX) and 407 ± 14 (PAR), in wastewater, while for CAC, the lowest and highest qₘ were 118 ± 7 (SMX) and 190 ± 16 (PAR) in ultrapure water and 123 ± 5 (SMX) and 160 ± 7 (CBZ) in wastewater. It was found that the matrix pH played a key role in these differences by controlling the surface electrostatic interactions between pharmaceutical and AC. Overall, it was evidenced the need of adsorption results in real matrices and demonstrated that AAC is a promising option to be implemented in tertiary wastewater treatments for pharmaceuticals’ removal. Graphical abstract Production of an alternative activated carbon (AC) comparing favourably with a commercial AC in the removal of neutral and positive pharmaceuticals from wastewater
Mostrar más [+] Menos [-]Traces of intact paraben molecules in endometrial carcinoma
2019
Doğan, Selen | Tongur, Timur | Erkaymaz, Taner | Erdogan, Gulgun | Unal, Betul | Sik, Bulent | Simsek, Tayup
Endometrial carcinoma is the most commonly encountered gynecological cancer in women worldwide and is also one of the popular models of the hormone-dependent carcinomas. This study was aimed to evaluate and compare the concentrations of five paraben molecules (methylparaben, ethylparaben, N-propylparaben, benzylparaben, isobutylparaben + N-butylparaben) in the endometrial and myometrial tissue samples of patients diagnosed with endometrial carcinoma and benign gynecologic diseases. A total of 88 patients were included in the study and chemical analysis was performed on 176 tissue samples. The study group comprised of 33 patients with endometrial carcinoma and 6 patients with endometrial intraepithelial neoplasia. The control group comprised of 49 patients. One endometrial and one myometrial tissue samples were collected from each patient. The analyses were performed using ultrahigh-performance liquid chromatography and tandem mass spectrometry (UHPLC-MS/MS). At least one type of paraben molecule was detected in 23.07% (9/39) of the patients in the study group, and in 2.04% (1/49) of the patients in the control group; this difference between the groups was statistically significant (p = .002). N-Propylparaben and isobutyl + N-butylparaben were the most frequently detected (in 7/10 of the samples) paraben molecules in the study. Tumor characteristics (tumor diameter, myometrial invasion, architectural grade, nuclear grade, lymphovascular space invasion, and tumor stage) were comparable between the two groups of endometrial carcinoma (paraben-detected and paraben-undetected groups). In conclusion, paraben molecules were more frequently detected in the endometrial carcinoma tissue samples than in the normal endometrium.
Mostrar más [+] Menos [-]A simple novel route for porous carbon production from waste tyre
2019
Mozaffarian, Mehrdad | Soleimani, Mansooreh | Bajgiran, Mojtaba Abbaszadeh
In this research, waste tyre rubber was used for activated carbon production with a novel route by modified physo-chemical approach. Potassium hydroxide and carbon dioxide were selected as chemical and physical activating agents, respectively and the process was carried out without carbonization under inert atmospheric conditions. The experiments were designed by applying the central composite design (CCD) as one of the subsets of response surface methodology (RSM). The effects of activation temperature (550–750 °C), activation time (15–75 min), impregnation ratio of KOH/rubber (0.75–3.75) and CO₂ flow rate (200–400 mL/min) on production yield and specific surface area of produced activated carbon were studied. Based on the results, the 2FI and quadratic models were selected for production yield and specific surface area, respectively. The activation temperature was the main effective parameter on both responses in this process. The production yield and specific surface area of produced activated carbon at optimized conditions for each model were 47% and 928 m²/g, respectively. BET, XRF, XRD, FT-IR, EDS and FE-SEM analyses were carried out on the optimized sample of specific surface area model in order to investigate the residual salts and morphological porous structures. Based on the surface properties and the presence of sulfur compounds in produced activated carbon, this activated carbon has the ability of eliminating heavy metals such as mercury from industrial waste water.
Mostrar más [+] Menos [-]Revisiting trade and environment nexus in South Africa: fresh evidence from new measure
2019
Udeagha, Maxwell Chukwudi | Ngepah, Nicholas
The paper revisits the dynamic effect of trade openness on environmental quality in South Africa by employing a fresh proxy of trade openness suggested by Squalli and Wilson (The World Economy 34:1745–1770, 2011) over the period 1960–2016. Contrary to the previous literature, the new proxy is constructed to take into consideration both South Africa’s trade share of its GDP and its relative size of trade in relation to the world trade in a specified period of time. Adopting this novel approach to capture openness, the study applies the autoregressive distributed lag (ARDL) bounds test for cointegration approach to investigate the long-run association between trade openness and environmental quality. Our findings show that the results of the long run are materially different from those of the short run. While trade openness has a significantly beneficial impact on CO₂ emissions in the short run, it has a measurably detrimental consequence on it in the long run. These findings are new to the literature and contrast with the previous studies. While confirming the existence of an inverted U-shaped curve that validates the existence of environmental Kuznets curve (EKC) hypothesis for South Africa, our results are further supported by the non-linear ARDL model, which reveals evidence of asymmetric pass-through effects of changes in trade openness on CO₂ emissions. This paper suggests that South Africa’s policymakers must continue to improve trade policy reform with complementary policies to create a less carbon-intensive environment and promote lasting value for reductions of greenhouse gas (GHG) emissions and constantly support the establishment of greener technologies that ultimately lower CO₂ emissions.
Mostrar más [+] Menos [-]Energy consumption and environmental quality in South Asia: evidence from panel non-linear ARDL
2019
Munir, Kashif | Riaz, Nimra
The objective of this study is to estimate the non-linear effect of energy consumption i.e. oil, gas, electricity, and coal consumption on CO₂ emission in South Asian countries. The study uses annual panel data of three South Asian countries i.e. Bangladesh, India, and Pakistan from 1985 to 2017 and applies panel non-linear ARDL methodology to examine the long-run and short-run relationship. Results show that an increase in gas, electricity, coal, and electricity consumption leads to an increase in the carbon dioxide emission, whereas decrease in electricity and coal consumption reduces the carbon dioxide emissions in the long run. Non-linear relationship exists between electricity consumption and CO₂ emissions as well as between coal consumption and CO₂ emissions in South Asian countries in the long run. Results of short run dynamics of individual countries show that non-linear relationship exists between oil consumption and CO₂ emissions, electricity consumption and CO₂ emissions, and coal consumption and CO₂ emissions in Bangladesh and Pakistan. Research and development centers are required to control pollution through new technologies, while discourage to use higher electricity and coal consumption as a source of energy for a healthier environment.
Mostrar más [+] Menos [-]Insight of soil amelioration process of bauxite residues amended with organic materials from different sources
2019
Dong, Yuanpeng | Shao, Yifei | Liu, Aiju | Liu, Xijuan | Wu, Mi | Hu, Xinxin | Zhang, Qian | Meng, Zilin
It aimed to investigate and evaluate the soil amelioration process of bauxite residues with the amendments of organic materials from different sources. Wheat straw, poultry manure compost, and biosolids were chosen as the added organic materials. A series of essential soil properties were analyzed to evaluate the effects of organic materials on the soil amelioration of bauxite residue. The results indicated that organic amendments could obviously improve the texture of bauxite residues by increasing large aggregates contents, and elevating its organic matter content and fertility level (such as TN and TP). At the same time, organic additions were effective in reducing bauxite residues’ salinity as pH, electrical conductivity and sodium content were obviously decreased in all rehabilitated treatments in comparison with control treatment. These improvements created sufficient conditions for a quick recovery of microbial communities in bauxite residues matrix. The maximum microbial biomass C increased to 0.642 g-C·kg⁻¹, and the activities of urease, catalase, and invertase were massively elevated, especially for those after a year of rehabilitation, although alkali-phosphatase was kept a less level compared with other biological parameters. The further principal analysis and cluster analysis indicated that after 1 year of organic amendment, the improved bauxite residues matrix was very close to the reference soil based on the measured soil microbial properties. All the results suggested that organic amendment is an effective way to stimulate the soil amelioration of bauxite residues, and among the three amended organic materials, wheat straw and biosolid were better in improving the abiotic environmental conditions as well as biotic function recovery in soil amelioration of bauxite residue.
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