خيارات البحث
النتائج 4641 - 4650 من 4,924
Effect of selenium nanoparticles against abnormal fatty acid metabolism induced by hexavalent chromium in chicken’s liver
2019
Luo, Min | Huang, Shucheng | Zhang, Jialu | Zhang, Lihong | Meman, K̲h̲ālid Maḥmūd | Jiang, Jinhuan | Zhang, Niya | Zhou, Donghai
The effect of selenium on excessive fatty acid–induced apoptosis and abnormal amino acid metabolism in the liver is well known, because it is an important site in the fatty acid metabolism pathway. However, the protective role of nano-elemental selenium (nano-Se) supplementation against hexavalent chromium (K₂Cr₂O₇)–induced abnormal fatty acid metabolism has not been evaluated yet. Therefore, we conducted chicken experiments with different nano-Se supplementation doses to investigate the role of nano-Se against Cr(VI)-induced adverse effects. For this purpose, a total of 120 1-day-old chicks were randomly divided into control group, Cr(VI)-exposed group, protection group, treatment group, prevention group, and nano-Se control group. The results of RT-qPCR showed that the nano-Se supplementation notably downregulated (P < 0.01) the messenger RNA (mRNA) expression levels of fatty acid synthase (FASN), whereas nano-Se supplementation significantly upregulated (P < 0.01) the mRNA expression level of acyl-coenzyme A oxidase 1 (ACOX1) in chicken’s liver at day 35 of the experiment. Similar results were further verified by western blot analysis. Moreover, nano-Se supplementation significantly enhanced and reduced the antibody expression levels of ACOX1 and FASN in immunohistochemical analysis, respectively. Thus, finally, it was concluded that nano-Se can alleviate K₂Cr₂O₇-induced abnormal fatty acid metabolism in chicken’s liver.
اظهر المزيد [+] اقل [-]Effects of commonly used therapeutic drugs, paracetamol, and acetylsalicylic acid, on key physiological traits of the sea snail Gibbula umbilicalis
2019
Giménez, Valéria | Nunes, Bruno
Over time, the consumption of pharmaceutical drugs has highly augmented, directly contributing for an increase of the discharges of these substances into sewage water due to excretion, and their direct release to the environment, with or without adequate treatment. Considering that part of the sewage water is dumped into rivers and seas, this is the major source of contamination of the aquatic environment. Paracetamol and acetylsalicylic acid are among the most worldwide consumed pharmaceutical drugs, frequently found in wastewater discharges and consequently in the aquatic environment in considerable amounts, posing ecotoxicity concerns especially towards aquatic non-target species. Thus, it is important to study the ecotoxicological implications that these drugs might pose to organisms from aquatic environments. The objective of this study was to assess the toxic effects of these two compounds on key biochemical features (antioxidant defenses and damage, metabolism, and cholinergic neurotoxicity) of the marine snail species Gibbula umbilicalis after an acute (96 h) exposure, simulating pulses of contamination. In order to understand the effects that those drugs have on this species, the biochemical biomarkers analyzed were the activities of catalase (CAT), glutathione-S-transferases (GSTs), cholinesterases (ChEs), and the levels of lipid peroxidation (TBARS). After acute exposure to paracetamol, catalase activity decreased significantly in organisms exposed to both highest concentrations; no significant alterations were observed for glutathione-S-transferases activity; TBARS concentration decreased significantly in organisms exposed to the intermediate and both highest concentrations, and cholinesterase activity increased significantly in animals exposed to the lowest concentration. However, after acute exposure to acetylsalicylic acid, catalase activity increased significantly; no significant alterations were observed for glutathione-S-transferases activity, and TBARS concentrations and cholinesterase activity increased. This set of data shows that G. umbilicalis is highly responsive to the presence of the tested drugs, and may thus be a promising species to serve as test organism in future marine ecotoxicological testing. The adoption of this species may broaden the offer of highly ecologically representative test organisms to be included in biomonitoring projects of the coastal and marine environment. Furthermore, it is possible to suggest that both drugs may pose significant deleterious effects of pro-oxidative origin to the physiology of the selected species, with potential adverse ecological consequences, even after short periods of exposure. The absence of neurotoxicity showed that despite being able to trigger antioxidant mechanisms, both drugs did not affect neurotransmission.
اظهر المزيد [+] اقل [-]One-pot synthesis of multi-functional and environmental friendly tannic acid polymer with Fe3+ and formaldehyde as double crosslinking agents for selective removal of cation pollutants
2019
Zhang, Mingming | Zhang, Shengxiao | Liu, Xingxing | Chen, Hou | Ming, Yongfei | Xu, Qiang | Wang, Zhenhua
A novel multi-functional and environmental friendly tannic acid polymer (Fe³⁺-TA-HCHO) with Fe³⁺ and formaldehyde as double crosslinking agents together with cysteine as heteroatom source was prepared by a one-pot hydrothermal method. Characterization with transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FT-IR), and elemental analysis demonstrated that the Fe³⁺-TA-HCHO possessed uniform structure and particle size as well as plentiful functional groups. The resulted Fe³⁺-TA-HCHO material as a adsorbent to remove methylene blue, sunset yellow, Pb²⁺, Hg²⁺, and AsO₃³⁻ from water. The results suggested that Fe³⁺-TA-HCHO polymer (pHpzc is 2.33) showed different adsorption properties for anionic pollutants (sunset yellow and AsO₃³⁻) and cationic pollutants (methylene blue, Pb²⁺, and Hg²⁺). The material exhibited remarkable selectivity for adsorption and separation of pollutants. The maximum adsorption capacities calculated from Langmuir model for methylene blue, Pb²⁺, and Hg²⁺ were 154.32, 819.67, and 699.30 mg g⁻¹, respectively. This is the first time that tannic acid polymer is synthesized by double crosslinking method, which not only developed a promising adsorbent for selective removal of cation pollutants, but also opened up a new avenue for synthesis and application of tannic acid polymer.
اظهر المزيد [+] اقل [-]The influence of selected pharmaceuticals on biogas production from laboratory and real anaerobic sludge
2019
Fáberová, Milota | Ivanová, Lucia | Szabová, Petra | Štolcová, Magdalena | Bodík, Igor
The presented study summarizes laboratory tests results to define the inhibition effect of selected pharmaceuticals on biogas production under anaerobic digestion conditions. Two sets of inhibition tests were realized: (i) with real anaerobic sludge (from municipal wastewater treatment plant (WWTP) where sludge is present and includes a wide spectrum of pharmaceuticals over a long period) and (ii) with laboratory sludge (sludge without pharmaceuticals). Methanogenic tests lasting 20 days were performed with three analgesics (diclofenac, ibuprofen, and tramadol), two antibiotics (amoxicillin and ciprofloxacin), β-blocker (atenolol), three psychoactive compounds (carbamazepine, caffeine, and cotinine), and a mixture of these compounds. All tests were performed with two concentrations of pharmaceuticals (10 μg/L and 500 μg/L). Results of the methanogenic tests showed the different behaviors of the investigated sludges in the presence of individual pharmaceuticals. Stimulation of anaerobic digestion was mostly detected for laboratory (unadapted) sludge (e.g., the addition of ibuprofen at a concentration of 500 μg/L increased biogas production by 61%). On the other hand, pharmaceuticals inhibited biogas production for real sludge (e.g., the addition of ciprofloxacin 500 μg/L decreased biogas production by 52%).
اظهر المزيد [+] اقل [-]Atmospheric deposition and air–soil exchange of polybrominated diphenyl ethers (PBDEs) in a background site in Central China
2019
Zhan, Lingxi | Lin, Tian | Cheng, Hairong | Wang, Zuwu | Cheng, Zhineng | Zhou, Deng | Qin, Zhengxin | Zhang, Gan
Jinsha (JSH) is one of the regional background sites in Central China. In this study, eight polybrominated diphenyl ethers (PBDEs) were measured in atmospheric deposition samples (dry particle, wet particle, and wet dissolved), air (gaseous and particle) samples, and soil samples that were collected from March 2012 to March 2013. Of all eight PBDEs, BDE-209 was the most abundant congener in both deposition samples and air/soil samples. Average dry particle, wet particle, and wet dissolved deposition fluxes of Σ₈PBDEs were 270 ± 310 pg m⁻² day⁻¹, 130 ± 210 pg m⁻² day⁻¹, and 250 ± 330 pg m⁻² day⁻¹, respectively, while those of BDE-209 were 210 ± 290 pg m⁻² day⁻¹, 80 ± 120 pg m⁻² day⁻¹, and 160 ± 290 pg m⁻² day⁻¹, respectively. Dry deposition velocities of individual PBDE ranged from 0.11 ± 0.15 cm s⁻¹ (BDE-183) to 0.24 ± 0.38 cm s⁻¹ (BDE-209), and total washout ratios ranged from 5.0 × 10³ (BDE-28) to 4.2 × 10⁴ (BDE-209). The calculated net air–soil gas exchange flux of Σ₈PBDEs was − 16 ± 13 pg m⁻² day⁻¹, suggesting the deposition status of PBDEs. The gas exchange flux at the air–soil interface was significantly lower than the deposition flux, which only accounted for 2.5% of the total deposition flux, implying that atmospheric deposition was an important input pathway for PBDEs to soils. Overall, the pollution level of the soil was relatively low, and the soil serves as a sink for PBDEs from adjacent regions.
اظهر المزيد [+] اقل [-]An empirical evaluation of financial development-carbon footprint nexus in One Belt and Road region
2019
Hafeez, Muhammad | Yuan, Chunhui | Sānval, K̲h̲uram Shahzād | Aziz, Babar | Iqbal, Kashif | Raza, Salman
The aspiration of study is to explore the financial development-carbon footprint nexus in One Belt and Road initiative (BRI) region utilizing the panel dataset from 1990–2017. The cross-sectional dependence tests and second-generation panel unit tests were applied to affirm the cross-section dependence and integration level. The panel regression estimators from the Driscoll-Kraay standard error method for robust estimators in the presence of cross-sectional dependence have been applied to compute the estimators concerning the financial development-carbon footprint nexus for One Belt and Road economies. The estimates infer that financial development, urban population, and FDI have an adverse effect on carbon footprint. Furthermore, economic growth and energy consumption pollute the environment by enhancing the carbon footprint. Based on findings, it infers that financial development is a potential instrument to keep the environment through financial reforms. The estimates signify that it is necessary to allocate resources for renewable energy, energy efficiency, and energy conservation projects in order to moderate environmental degradation.
اظهر المزيد [+] اقل [-]Protective effects of quercetin supplementation against short-term toxicity of cadmium-induced hematological impairment, hypothyroidism, and testicular disturbances in albino rats
2019
Badr, Gehan M. | Elsawy, Hany | Sedky, Azza | Eid, Rania | Ali, Awatef | Abdallah, Basem M. | Alzahrani, Abdullah M. | Abdel-Moneim, Ashraf M.
The aim of this study was to evaluate the probable protective effect of quercetin (QUE) against cadmium (Cd)-induced sub-chronic toxicity in rats. Adult male rats were given either Cd (as cadmium chloride; 5 mg/kg) alone or in combination with QUE (50 mg/kg) daily for 4 weeks by oral gavage. At the end of the experimental period, Cd accumulation, and selected hematological, thyroid, and reproductive markers were assessed. Results revealed that Cd treatment significantly increased Cd concentrations in blood, thyroid gland, and testicular tissue of rats. Cd also caused a decline in hemoglobin content, hematocrit value, and total erythrocyte and leucocyte counts. Further, significant suppressions in the blood levels of hormones related to thyroid gland function, and male reproductive hormones (i.e., testosterone, luteinizing hormone and follicle-stimulating hormone), were observed in Cd-treated rats compared to the control. In parallel, low sperm count and sperm motility, increased sperm abnormalities, and marked pathology occurred in testis. Combination with QUE recorded amelioration of the deleterious effects of Cd, involving regulation of hematological toxicity and thyroid hormonal levels and subsequently modulation of testicular function. In conclusion, it appears that dietary QUE can rescue from Cd-induced hematological dysfunctions and testicular damage by reversing the hypothyroid state.
اظهر المزيد [+] اقل [-]Occurrence of PCDD/PCDFs, dioxin-like PCBs, and PBDEs in surface sediments from the Neva River and the Eastern Gulf of Finland (Russia)
2019
Metelkova, Larisa | Zhakovskaya, Zoya | Kukhareva, Galina | Rybalko, Alexander | Nikiforov, Vladimir
A total of 26 samples of surface sediments collected in the Neva River (including the St. Petersburg city area) and in the Russian part of the Gulf of Finland were analyzed for 17 polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs), 12 dioxin-like polychlorinated biphenyls (dl-PCBs), and 10 polybrominated diphenyl ethers (PBDEs). The concentrations of total PCDD/Fs and dl-PCBs in sediments ranged from < 0.05 to 219 pg g⁻¹ d.w. and from 44 to 246,600 pg g⁻¹ d.w. respectively. The total World Health Organization toxic equivalent (WHO-TEQPCDD/F ₊ PCB) values varied between 0.01 and 59.0 pg g⁻¹. In the majority of cases, the PCDD/F and dl-PCB concentrations do not exceed the threshold effect level (TEL) recommended by Helsinki Commission (HELCOM) as quantitative target for the sum of PCDD/Fs and dl-PCBs. The congener profile indicates that combustion is the primary source of PCDD/Fs in most of the studied samples. For the PCBs, the historical use of technical PCB products was identified as the major source. ΣPBDE₁₀ concentrations ranged from 0.004 to 1.8 ng g⁻¹ d.w. The congener profile results show that BDE-47 (tetra-BDE) is the dominant congener in sediment samples. According to the sediment and water quality guidelines established in the EU (PNEC) and in Canada (FEQG), all the samples studied can be classified as lowly contaminated by PBDEs. The sediment concentrations of PCDD/Fs, dl-PCBs, and PBDEs measured in this study were comparable to or lower than those reported for other areas of the Baltic Sea.
اظهر المزيد [+] اقل [-]Butyrylcholinesterase—a potential plasma biomarker in manganese-induced neurobehavioral changes
2019
Anjum, Adiba | Biswas, Sheta | Rahman, Mizanur | Rahman, Atiqur | Siddique, Abu Eabrahim | Karim, Yeasir | Aktar, Sharmin | Nikkon, Farjana | Haque, Azizul | Himeno, Seiichiro | Hosāina, Khāleda | Saud, Zahangir Alam
Groundwater particularly drinking water contamination with metals has created an environmental disaster in Bangladesh. Manganese (Mn), an essential trace element, plays a key role in the development and function of the brain. Excess Mn exposure is reported to be associated with complex neurological disorders. Here, we have found a notably large extent of Mn above the permissive limit in the tube-well water of Rajshahi and Naogaon districts in Bangladesh. Higher levels of Mn in hair and nail samples, and a decreasing level of butyrylcholinesterase (BChE) activity were detected in plasma samples of the human subjects recruited from Naogaon district. Mn concentrations in water, hair, and nails were negatively correlated with the plasma BChE levels in Mn-exposed populations. To compare and validate these human studies, an animal model was used to determine the in vivo effects of Mn on neurobehavioral changes and blood BChE levels. In elevated plus maze, the time spent was significantly reduced in open arms and increased in closed arms of Mn-exposed mice compared to control group. The mean latency time to find the platform was declined significantly in control mice compared to Mn-treated group during 7 days in Morris water maze test, and Mn-exposed group also spent significantly less time in the desired quadrant as compared to the control group in probe trial. BChE activity was significantly reduced in Mn-exposed mice compared to control mice. Taken together, these results suggest that plasma BChE levels may serve as reliable biomarker of Mn-induced neurotoxicity related to behavioral changes.
اظهر المزيد [+] اقل [-]Residues of endosulfan in cotton growing area of Vehari, Pakistan: an assessment of knowledge and awareness of pesticide use and health risks
2019
Ashfaq, Ahmad | Shāhid, Muḥammad | Khalid, Sana | Zaffar, Habiba | Naqvi, Tatheer | Pervez, Arshid | Vēlāyutan̲, T. A. | Ali, Muhammad Arif | Abbas, Ghulam | Nasim, Wajid
This study is based on self-reported information collected from selected farmers of Vehari District, Punjab, Pakistan, to determine their technical knowledge and awareness about pesticide use and associated environmental and health risks. Moreover, soil contamination by routinely used persistent organochlorine pesticide, endosulfan, was also evaluated. Survey data revealed very low literacy rate (on an average 9th grade education) and technical knowledge (almost missing) of the farmers in Vehari District. The farmers are unable to fully read and understand the instructions about the use of pesticide marked on the containers. They are not fully aware of pesticide persistence and toxicity (73%), unable to identify cotton pests and diseases (86%), and do not know which crop to grow in cotton adjacent fields (100%). Data also revealed that the farmers (100%) do not follow safety measure during pesticide application and are unaware of pesticide toxicity symptoms in human as well as the basic first-aid practices (89%).Poor literacy rate and lack of technical knowledge of farmers in Vehari regarding pesticide use and handling are posing serious environmental and health risks among the local inhabitants, particularly among farmers. Soil analysis results showed that concentration of α- and β-endosulfan ranged from 0–14 to 0–14.64 μg/mg, respectively. Principal component analysis showed that soil organic matter is the key soil parameter controlling the occurrence and fate of endosulfan under sandy loam soil conditions of Vehari District. There is a serious need of improving technical and environmental knowledge of farmer about pesticide risks on human health in the studied area, in particular, and the entire country in general. Findings are of great use for policymaking in Pakistan to minimize pesticide risks in Pakistan.
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