خيارات البحث
النتائج 4781 - 4790 من 4,937
Amelioration of titanium dioxide nanoparticle reprotoxicity by the antioxidants morin and rutin النص الكامل
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.
اظهر المزيد [+] اقل [-]Effects of mutual grafting on cadmium accumulation characteristics of first post-generations of Bidens pilosa L. and Galinsoga parviflora Cav النص الكامل
2019
Li, Hongyan | Wang, Jin | Lin, Lijin | Liao, Ming’an | Lv, Xiulan | Tang, Yi | Wang, Xun | Xia, Hui | Liang, Dong | Ren, Wei | Jiang, Wei
We studied the effects of mutual grafting on cadmium (Cd) accumulation characteristics on the first post-generations of the Cd-hyperaccumulator plants Bidens pilosa L. and Galinsoga parviflora Cav. The seeds from scions and rootstocks of B. pilosa and G. parviflora were collected and planted in Cd-contaminated soil in pot and field experiments. In the pot experiment, rootstock treatment increased the shoot biomass of B. pilosa post-grafting generations, compared with ungrafted B. pilosa, but decreased the Cd content in shoots and Cd extraction by shoots of post-grafting generations; scion treatment decreased or had no significant effect. Mutual grafting resulted in no significant differences to the photosynthetic pigment contents in B. pilosa post-grafting generations. Compared with ungrafted G. parviflora, scion treatment increased the shoot biomass, photosynthetic pigment content, and Cd extraction by shoots of G. parviflora post-grafting generations, but rootstock treatment did not lead to significant differences. Mutual grafting resulted in no significant differences to the Cd contents in shoots of G. parviflora post-grafting generations. In the field experiment, only rootstock treatment increased the shoot biomass of B. pilosa post-grafting generations, and only scion treatment increased the shoot biomass and the Cd extraction by shoots of G. parviflora post-grafting generations. Therefore, mutual grafting of scions may enhance the phytoremediation ability of G. parviflora first post-grafting generations.
اظهر المزيد [+] اقل [-]Revisiting trade and environment nexus in South Africa: fresh evidence from new measure النص الكامل
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.
اظهر المزيد [+] اقل [-]Energy consumption and environmental quality in South Asia: evidence from panel non-linear ARDL النص الكامل
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.
اظهر المزيد [+] اقل [-]Seasonal variation of the organic and inorganic composition of sugarcane vinasse: main implications for its environmental uses النص الكامل
2019
de Godoi, Leandro Augusto Gouvêa | Camiloti, Priscila Rosseto | Bernardes, Alan Nascimento | Sanchez, Bruna Larissa Sandy | Torres, Ana Paula Rodrigues | da Conceição Gomes, Absai | Botta, Lívia Silva
Sugarcane vinasse is the main waste stream of the Brazilian agroindustry. The typical composition of sugarcane vinasse gives it a high polluting potential that implies the necessity to define sustainable strategies for managing this waste. Knowledge of the inorganic and organic composition of vinasse and its seasonal variation is extremely important to conduct scientific research to define alternative managements for vinasse disposal other than fertigation. This study evaluated the variability of vinasse composition throughout the same harvesting season and among three harvesting seasons of one Brazilian annexed biorefinery (2015–2017). The contents of chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), total solids (TS), suspended solids (SS), salinity (K⁺, Na⁺, Ca²⁺, Mg²⁺, Cl⁻, F⁻), nutrients (N, P, S), trace metals (Al³⁺, As²⁺, Ba²⁺, Cd²⁺, Cr³⁺, Co²⁺, Cu²⁺, Fe²⁺, Pb²⁺, Mn²⁺, Hg²⁺, Mo²⁺, Ni²⁺, Se²⁺, Zn²⁺), and specific soluble organic compounds (sugars, alcohols, and organic acids), as well as pH and conductivity, were monitored in 13 samples. The results indicated that sugarcane vinasse is a suitable feedstock for biological treatments, such as anaerobic digestion processes for energy recovery, as well as substrate for biomass (e.g., microalgae, energy crops, lignocellulosic biomass) growth. The application of a previous treatment makes vinasse a more environmentally friendly natural fertilizer for land fertigation.
اظهر المزيد [+] اقل [-]Traces of intact paraben molecules in endometrial carcinoma النص الكامل
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.
اظهر المزيد [+] اقل [-]A simple novel route for porous carbon production from waste tyre النص الكامل
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.
اظهر المزيد [+] اقل [-]Experimental investigation of diesel engine performance fuelled with the blends of Jatropha curcas, ethanol, and diesel النص الكامل
2019
Kavitha, Kutuva Rajaraman | Beemkumar, Nagappan | Rajasekar, Rajendiran
Nonrenewable fossil fuels show increased demand and with fossil fuels at a rapid depleting stage, there seems to be an increase in requirement for alternative fuels too. Biofuels and blended fossil fuels are one of a kind. Nonedible jatropha (Jatropha curcas) oil-based methyl ester was produced and mixed with ethanol and blended with conventional diesel in various compositions. Jatropha biodiesel is used because of its great blending capacity with diesel. Sodium hydroxide is used as a catalyst which allows miscibility between ethanol and diesel. In present epoch, the paucity of fossil fuels and its adverse impact have driven researchers to focus on alternative fuels. Biodiesel is one of the most favorable and promising alternatives in the application of automobiles, boilers, gas turbines, etc. This study targets at finding the engine performance and emission characteristics under various load conditions on Kirloskar single-cylinder VCR research engine by blending both jatropha biodiesel and ethanol with base diesel at various compositions. Both jatropha biodiesel and ethanol have high calorific value which is a most important factor for engine power production. The performance analysis showed that the biodiesel blend of 98% diesel with 1.5% jatropha biodiesel and 0.5% (D98J1.5E0.5) of ethanol had a significant improvement in the engine performance than the conventional diesel.
اظهر المزيد [+] اقل [-]A mini review of bisphenol A (BPA) effects on cancer-related cellular signaling pathways النص الكامل
2019
Nomiri, Samira | Hoshyar, Reyhane | Ambrosino, Concetta | Tyler, Charles R. | Mansouri, Borhan
Bisphenol A (BPA) is a plasticizer used widely in many industrial products and is now well established as an endocrine-disrupting chemical (EDC). BPA readily leaches out from these products into the environment and into foodstuffs (from packaging materials) and human exposure can be considerable. Many studies have shown that BPA exposure is associated with a range of chronic human health conditions, including diabetes, cardiovascular disorders, polycystic ovarian disease, hepatotoxicity, and various types of cancer. BPA exerts its effects through deregulating cell signaling pathways associated with cell growth, proliferation, migration, invasion, and apoptosis. Previous studies on the molecular mechanisms of BPA have illustrated a variety of pathways impaired at very low exposure concentrations and that stimulate cellular responses relating to tumorigenesis both in cancer onset and progression. In this mini review, the recent advancements made through in vitro analyses are reported on for the effect of BPA on various cellular signaling pathways focusing on the signaling pathways that play a major role in carcinogenesis.
اظهر المزيد [+] اقل [-]Endocrine disrupting pesticides in soil and their health risk through ingestion of vegetables grown in Pakistan النص الكامل
2019
Ali, Neelum | K̲h̲ān, Sardār | Khan, Muhammad Amjad | Waqas, Muhammad | Yao, Huaiying
A comprehensive study was conducted to appraise the concentrations of 30 endocrine disrupting pesticides (EDPs) in soil and vegetable samples collected from Khyber Pakhtunkhwa, Pakistan. The sum of 30 EDPs (Σ₃₀EDPs) ranged from 192 to 2148 μg kg⁻¹ in the collected soils. The selected EDP concentrations exceeded their respective limits in most of the tested soils and showed great variation from site to site. Similarly, high variations in Σ₃₀EDP concentrations were also observed in vegetables with the highest mean concentration in lettuce (28.9 μg kg⁻¹), followed by radish (26.6 μg kg⁻¹), spinach (25.7 μg kg⁻¹), onion (16.2 μg kg⁻¹), turnip (15.6 μg kg⁻¹), and garlic (14.7 μg kg⁻¹). However, EDP levels in all studied vegetables were within FAO/WHO limits. The mean bioconcentration factor values were observed < 1 for all the studied vegetables. The health risk assessment revealed that the incremental lifetime cancer risk (ILCR) of Σ₃₀EDPs associated with vegetable ingestion was below the acceptable risk level (1 × 10⁻⁶), showing no cancer risk to local inhabitants. However, exposure to endocrine disruptor and probable carcinogen heptachlor epoxide poses a potential non-cancer risk (hazard quotient (HQ > 1)) to children through vegetable consumption. The presence of banned EDPs in soils and vegetables of the study area indicates the stability of these legacy chemicals in the environment from over usage in the past or illegal current application for agricultural purposes. Graphical abstract
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