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Resultados 4241-4250 de 4,937
Efficiency of maternal-fetal transfer of perfluoroalkyl and polyfluoroalkyl substances Texto completo
2019
Perfluoroalkyl and polyfluoroalkyl substances (PFASs) can be transferred from a mother to her fetus during pregnancy and adversely affect fetal development. However, the efficiency and influencing factors of PFASs maternal–fetal transfer remain unclear. We measured the levels of six perfluoroalkylcarboxylates, three perfluoroalkylsulfonates, and one sulfonamide in 369 pairs of maternal and umbilical cord serum and examined the transplacental transfer efficiency (TTE) of PFASs by the functional group and carbon chain length in a prospective birth cohort in Shandong, China. All ten PFASs were detected in both maternal and umbilical cord serum in nearly all samples. Maternal and cord levels were closely correlated (the correlation coefficient [r] ranging from 0.485 to 0.908) in most PFASs except perfluorobutane sulfonic acid (PFBS) (r = 0.159). TTE was significantly affected by the functional group and carbon chain length. Compared to perfluoroalkylcarboxylates, perfluoroalkylsulfonates had a lower ratio of maternal to fetal transfer. A U-shaped relationship between carbon chain length and TTE was observed for perfluoroalkylcarboxylates while a monotonic descending trend was identified between TTE and the increasing carbon chain length for perfluoroalkylsulfonates. PFASs can readily pass through the placenta. The functional group and carbon chain length are important determinants for the TTE of PFASs.
Mostrar más [+] Menos [-]Removal of chlorpheniramine and variations of nitrosamine formation potentials in municipal wastewaters by adsorption onto the GO-Fe3O4 Texto completo
2019
Chlorpheniramine is a pharmaceutical pollutant and a precursor of carcinogenic nitrosamines during disinfection/oxidation. In our previous study, graphene oxide coated with magnetite (GO-Fe₃O₄) was capable of removing chlorpheniramine in deionized water by adsorption. This study investigated the removal of chlorpheniramine and its nitrosamine formation potentials (FPs) by adsorption onto magnetic GO-Fe₃O₄, with respect to the influence by using real municipal wastewaters as the background. In the results, the adsorption performances of chlorpheniramine in wastewaters decreased in the order: GO-Fe₃O₄ suspension > GO-Fe₃O₄ particles > activated carbon. Chlorpheniramine adsorptions on GO-Fe₃O₄ particles and activated carbon were reduced by using real wastewaters as the background, whereas chlorpheniramine adsorption on GO-Fe₃O₄ suspension was enhanced due to the effects of surface charge on GO-Fe₃O₄ and ionic strength variation in water. The fittings of adsorption isotherms indicated that the wastewater background reduced the surface heterogeneity of GO-Fe₃O₄ suspension and improved the adsorption performance. Appreciable removal efficiencies of NDMA and other nitrosamine FPs were observed when GO-Fe₃O₄ particles were added in real wastewaters. However, when chlorpheniramine was present in wastewaters, chlorpheniramine adsorption and degradation reaction simultaneously occurred on the surface of GO-Fe₃O₄, increasing NDMA and other nitrosamine FPs in wastewaters after GO-Fe₃O₄ addition for chlorpheniramine adsorption. The assumption was further demonstrated by observing the NDMA-FP increase during chlorpheniramine adsorption on GO-Fe₃O₄ in deionized water. GO-Fe₃O₄ is a potential adsorbent for chlorpheniramine removal. Nevertheless, the low treatment efficiencies at high doses limit its application for nitrosamine FP adsorptions in real wastewaters.
Mostrar más [+] Menos [-]1H NMR-based serum metabolomics analysis of the age-related metabolic effects of perinatal exposure to BPA, BPS, BPF, and BPAF in female mice offspring Texto completo
2019
Meng, Zhiyuan | Zhu, Wentao | Wang, Dezhen | Li, Ruisheng | Jia, Ming | Yan, Sen | Yan, Jin | Zhou, Zhiqiang
The widespread application of bisphenols (BPs) in the industry has made them ubiquitous in the environment, causing potential environmental risks. Its unknown impacts on human being have received more and more attention. In this study, we have assessed the metabolic effects of perinatal exposure to bisphenol A (BPA) and its substitutes (bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF)) in female mice adolescent offspring and female mice adulthood offspring. ¹H NMR-based serum metabolomics showed that metabolic profiles were disturbed with BPA and its three substitutes exposure in female mice adolescent offspring and female mice adulthood offspring. In addition, age-related metabolic effects were found based on changes in serum endogenous metabolites and metabolic pathways. Specifically, metabolic pathway analysis showed that major disturbed metabolic pathways in female mice adulthood offspring compare with female mice adolescent offspring also changed significantly. With the increase of age of the female mice offspring, changes in the metabolic pathways became more obvious in the BPA treatment group. Conversely, partially disturbed metabolic pathways were restored in the BPS, BPF, and BPAF treatment groups. In conclusion, perinatal exposure to BPA and its three substitutes significantly interferes with metabolic profiles and metabolic pathways, and this metabolic effects were age-related. These results offer more detailed information about the age-related metabolic effects of perinatal exposure to BPA, BPS, BPF, and BPAF in female mice offspring and provide data for systematic evaluation of the health risk assessment of BPA and its substitutes.
Mostrar más [+] Menos [-]Enhanced reductive dechlorination of 1,1,1-trichloroethane using zero-valent iron-biochar-carrageenan microspheres: preparation and microcosm study Texto completo
2019
Ji, Changling | Meng, Liang | Wang, Hualin
In this study, a composite remediation material for the enhanced reductive dechlorination (ERD) of 1,1,1-trichloroethane (1,1,1-TCA) in aqueous solution was prepared. This material was comprised of biochar as the carrier and adsorbent, and carrageenan (CG) as the embedding medium to entrap the organic carbon sources and zero-valent iron (ZVI). We determined the suitable biochar dosage and organic carbon source in the composite alongside the optimal preparation conditions. Furthermore, using an anaerobic microcosm study, we discussed the performance and possible mechanisms of the composite on 1,1,1-TCA removal in aqueous solution. From this, we found that the suitable dosage of biochar in water during the preparation of composite microspheres was 0.2% (w/v). Under this condition, the biochar had a strong capacity to adsorb 1,1,1-TCA with a removal efficiency of 84.2%. Soluble starch was selected as the appropriate organic carbon source, because starch-microspheres show an excellent slow-release effect in water. The optimal preparation conditions of microspheres were identified as follows: 2% CG (w/v) colloidal solution, 6% CaCl₂ (w/v) solution, and a 12-h curing time. After 25-day incubation with the composite prepared under optimized conditions, the removal efficiency of 1,1,1-TCA was 95.68%, which was 24.69% higher than that observed in the microcosm with a commercial remediation material. The scanning electron microscopy (SEM) images show that the amounts of ZVI and soluble starch inside the microsphere decreased obviously, while the biochar amount remained about the same. This indicates that 1,1,1-TCA in aqueous solution was mainly removed via soluble starch-enhanced biotic reductive dechlorination and ZVI-enhanced abiotic reductive dechlorination. The changes in microbial community structure demonstrate that the composite stimulated the activities of functional anaerobic bacteria, in particular, regarding dechlorination and fermentation abilities in the microcosm, therefore enhancing the anaerobic biodegradation of 1,1,1-TCA. This study suggests that the composite, entrapping biochar, ZVI, and organic carbon source in CG microspheres can significantly enhance the reductive dechlorination of 1,1,1-TCA in aqueous solution. We anticipate this novel remediation material could be successfully applied to the in situ ERD remediation of natural groundwater mainly contaminated with 1,1,1-TCA.
Mostrar más [+] Menos [-]Feasibility of anaerobic digestion on the release of biogas and heavy metals from rice straw pretreated with sodium hydroxide Texto completo
2019
Xin, Liqing | Guo, Zhaohui | Xiao, Xiyuan | Peng, Chi | Zeng, Peng | Feng, Wenli | Xu, Wenxuan
The feasibility of anaerobic digestion on the release of biogas and heavy metals from contaminated rice straw pretreated with NaOH solution was studied. The results show that NaOH pretreatment can significantly boost the release of biogas and heavy metals from rice straw using anaerobic digestion. Under the optimal conditions for biomass pretreated 6% (w/w) NaOH with a solid-to-solution ratio of 1:20, total biogas and methane yields of 446.3 mL/g and 263.5 mL/g volatile solids were achieved, which were 22.18% and 41.59% higher than those of the control without NaOH pretreatment, respectively, and the release percentages of Cd, Pb, Cu, and Zn from rice straw reached 86.95–97.69%. The release of heavy metals from rice straw can contribute to both the degradation of lignin by NaOH pretreatment and the utilization/transformation of lignocellulose via anaerobic digestion. The acidification levels and total volatile fatty acid contents significantly influence on the release of heavy metals. Based on the Illumina HiSeq sequencing analysis, the dominant phyla in the biogas residues were proteolytic (Bacteroidetes) and hydrogen-producing (Firmicutes) bacteria, while the growth of Methanospirillum and Methanosaeta in anaerobically digested effluent was promoted. The results revealed that anaerobic digestion combined with NaOH pretreatment is suitable for the disposal of heavy metal–contaminated biomass.
Mostrar más [+] Menos [-]The remediation potential and kinetics of cadmium in the green alga Cladophora rupestris Texto completo
2019
Zhang, Hui-min | Geng, Geng | Wang, Jun-Jie | Xin, Yue | Zhang, Qian | Cao, De-ju | Ma, You-hua
This study determined the subcellular distribution, chemical forms, and effects of metal homeostasis of excess Cd in Cladophora rupestris. Biosorption data were analyzed with Langmuir and Freundlich adsorption models and kinetic equations. Results showed that C. rupestris can accumulate Cd. Cd mainly localized in the cell wall and debris (42.8–68.2%) of C. rupestris, followed by the soluble fraction (22.1–38.4%) observed in C. rupestris. A large quantity of Cd ions existed as insoluble CdHPO₄ complexed with organic acids, Cd(H₂PO₄)₂, Cd-phosphate complexes (FHAC) (43.2–56.0%), and pectate and protein-integrated Cd (FNₐCₗ) (30.8–43.2%). The adsorption data were well fitted by the Freundlich model (R² = 0.933) and could be described by the pseudo-second-order reaction rate (R² = 0.997) and Elovich (R² = 0.972) equations. Related parameters indicated that Cd adsorption by C. rupestris is a heterogeneous diffusion. Cd promoted Ca and Zn uptake by C. rupestris. Cu, Fe, Mn, and Mg adsorption was promoted by low Cd concentrations and inhibited by high Cd concentrations. Results suggested that cell wall sequestration, vacuolar compartmentalization, and chemical morphological transformation are important mechanisms of Cd stress tolerance by C. rupestris. This study suggests that C. rupestris has bioremediation potential of Cd.
Mostrar más [+] Menos [-]Comparative studies on endogenic stress hormones, antioxidant, biochemical and hematological status of metabolic disturbance in albino rat exposed to roundup herbicide and its active ingredient glyphosate Texto completo
2019
Owagboriaye, Folarin | Dedeke, Gabriel | Ademolu, Kehinde | Olujimi, Olanrewaju | Aladesida, Adeyinka | Adeleke, Mistura
There have been growing concerns and uncertainty about reports attributing the metabolic disturbance induced by a commercial formulation of glyphosate-based herbicide to its active ingredient. We therefore compared the effects of Roundup Original® and its active ingredient glyphosate on some hypothalamic-pituitary-adrenal (HPA) hormones and oxidative stress markers, biochemical and hematological profiles in 56 adult male albino rats randomly assigned to seven treatments of eight rats per treatment. The rats were orally exposed to Roundup Original® and its active ingredient daily at 3.6 mg/kg body weight (bw), 50.4 and 248.4 mg/kgbw of glyphosate equivalent concentrations for 12 weeks, while control treatment received distilled water. Serum concentrations of corticosterone, adrenocorticotropic hormone, aldosterone and concentration of oxidative stress marker, biochemical and hematological profiles in the blood were determined. Concentrations of corticosterone and aldosterone were significantly higher (p < 0.05) in rats treated with Roundup in a dose-dependent manner. Reduced glutathione concentration, catalase, and butyrylcholinesterase activities reduced significantly in rats treated with Roundup relative to those treated with the active ingredient. Lipid peroxidation was observed in rats treated with Roundup. Biochemical and hematological profiles of rats treated with Roundup were significantly altered (p < 0.05). However, significant changes in only acid phosphatase, lactase dehydrogenase, bilirubin, and white blood cells in rats treated with the active ingredient at 50.4 mg/kg were observed. The severe metabolic disturbance and stress observed in rats treated with the commercial formulation of Roundup herbicide may not be associated with the mild changes induced by the active ingredient.
Mostrar más [+] Menos [-]Larvicidal and pupicidal activities of eco-friendly phenolic lipid products from Anacardium occidentale nutshell against arbovirus vectors Texto completo
2019
de Carvalho, George Harrison Ferreira | de Andrade, Milene Aparecida | de Araújo, Carla Nunes | Santos, Maria Lucília | de Castro, Natália Alves | Charneau, Sébastien | Monnerat, Rose | de Santana, Jaime Martins | Bastos, Izabela Marques Dourado
Aedes aegypti and Culex quinquefasciatus are vectors of diseases that constitute public health problems. The discovery of products capable of inhibiting their development which are less harmful to the environment would have a huge impact on vector control. Here, natural cashew nut shell liquid (CNSL), technical CNSL, anacardic acid, cardanol, and cardol were isolated from Anacardium occidentale and evaluated for larvicidal and pupicidal activity against Ae. aegypti and Cx. quinquefasciatus under laboratory and field conditions. The activities of phenol, resorcinol, salicylic acid, and pentadecane, commercial chemicals similar in structure to nut shell derivatives, were also evaluated. All of the fractions extracted from A. occidentale oil exerted larvicidal effects against both mosquito species (LC₅₀ 5.4–22.6 mg/L), and two of the aforementioned were effective against pupae (LC₅₀ 90.8–109.7 mg/L). Of all the fractions tested, cardol demonstrated the strongest larvicidal and pupicidal effects and presented the most prolonged residual activity against the larvae and pupae of Ae. aegypti and Cx. quinquefasciatus under field conditions. This study suggests that A. occidentale nut shell derivatives are sustainable and promising candidates for the development of novel insecticides to overcome the problem of harmful chemical insecticides.
Mostrar más [+] Menos [-]The remedial effect of Thymus vulgaris extract against lead toxicity-induced oxidative stress, hepatorenal damage, immunosuppression, and hematological disorders in rats Texto completo
2019
El-Boshy, Mohamed E. | Refaat, Bassem | Qasem, Ahmed H. | Khan, Anmar | Ghaith, Mazen | Almasmoum, Hussain | Mahbub, Amani | Almaimani, Riyad A.
The Thymus vulgaris (T. vulgaris) has been used in foods for the flavor, aroma, and preservation and in folk medicines. The objective of the present work was to determine the antioxidant and protective effects of T. vulgaris extract against lead (Pb)-intoxicated rats. A thirty-two male Sprague-Dawley were randomly assigned into 4 equal groups and treated for six weeks as follows: group I (GP-I), served as negative control; GP-II, -III, and -IV received either Pb acetate in drinking water (500 mg/L), T. vulgaris extract (500 mg/kg/day) by oral gavage or Pb acetate with T. vulgaris extract, respectively. Blood samples were collected at the end of the study week 6 to measure the hepatic and renal biochemical markers, complete blood count alongside the serum levels of interleukin (IL)-1β, IL-6, IL-10, tumor necrosis (TNF)-α, and interferon (IFN)-γ. Additionally, liver and kidney tissue specimens were collected for histopathology as well as to measure the antioxidant-reduced glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD) alongside the lipid peroxidation marker, malonaldehyde (MDA). The results indicated that Pb toxicity increased the serum levels of IL-1β, IL-6, and TNF-α, whereas IL-10 and IFN-γ were reduced. The results showed disturbed liver and renal functions; increased serum levels of ALT, AST, ALP, total bilirubin, creatinine, and urea; and decreased total protein, albumin, and calcium. The GSH, Gpx, and CAT levels were significantly decreased in the Pb-administrated group, while MDA was increased. However, regarding the hepatorenal markers, those animals treated with T. vulgaris alone did not induce any significant changes. Moreover, the combined treatment with T. vulgaris extract together with Pb showed significant improvement in Pb-induced toxicity in all the tested parameters compared to the negative control group. We investigated the potential protective effects of the medicinal plant T. vulgaris in vivo, since there are no publications that address the potential protective effect of this leaf extract against Pb-induced hepatorenal toxicity. Our studies concluded that the T. vulgaris extract reduces Pb overload in hepatorenal tissues, and that this has a potential immunomodulatory role, antioxidant activity, and a protective effect against Pb toxicity.
Mostrar más [+] Menos [-]Characterization of blaNDM-harboring, multidrug-resistant Enterobacteriaceae isolated from seafood Texto completo
2019
Dāsa, Udaẏa Nārāẏaṇa | Singh, Asem Sanjit | Lekshmi, Manjusha | Nayak, Binaya Bhusan | Kumar, Sanath
Carbapenem-resistant Enterobacteriaceae (CRE) have evolved into a major challenge to antibiotic therapy worldwide. The problem is more confounding when wider dissemination of CRE occurs in the community and the environment. In this study, six blaNDM-harboring Enterobacteriaceae, four Klebsiella pneumoniae, and two Escherichia coli, isolated from seafood, were characterized with respect to their antibiotic resistance and the genetic factors responsible for these resistances. The isolates were resistant to all β-lactam antibiotics, quinolones, trimethoprim–sulfamethoxazole, chloramphenicol, and tetracycline and were susceptible to colistin, polymixin B, fosfomycin, and tigecycline. Four isolates harbored New Delhi metallo β-lactamase (blaNDM₋₅ genes, while one isolate each harbored blaNDM₋₁ and blaNDM₋₂ genes, respectively. The blaNDM genes in all the isolates were flanked by an upstream, truncated ISAba125, and downstream bleMBL-trpF genes. Conjugation experiments showed that the NDM plasmids were readily transmissible. Further, the two blaNDM-positive E. coli isolates belonged to the multidrug-resistant ST131 clone. This study highlights the growing danger of seafood as carriers of multidrug-resistant bacteria leading to their wider dissemination in the community.
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