Affiner votre recherche
Résultats 1881-1890 de 7,989
Associations of exposure to perfluoroalkyl substances individually and in mixtures with persistent infections: Recent findings from NHANES 1999–2016
2021
Bulka, Catherine M. | Avula, Vennela | Fry, Rebecca C.
Certain viruses and parasites can cause persistent infections that often co-occur and have been associated with substantial morbidity and mortality. Separate lines of research indicate exposures to per- and polyfluoroalkyl substances (PFAS) suppress the immune system. We hypothesized that PFAS exposures might systematically increase susceptibility to persistent infections resulting in a higher pathogen burden. We used data from 8778 individuals (3189 adolescents, 5589 adults) in the nationally-representative U.S. National Health and Nutrition Examination Survey (NHANES) 1999–2016 to examine cross-sectional associations between serum concentrations of four highly detected PFAS (PFOS, PFOA, PFHxS, PFNA) with the presence of antibodies to cytomegalovirus, Epstein Barr virus, hepatitis C and E, herpes simplex 1 and 2, HIV, T. gondii, and Toxocara spp. Seropositivity was summed to calculate a pathogen burden score reflecting the total number of infections. Separate survey-weighted multivariable regression models were fitted to analyze PFAS individually and quantile g-computation was used to analyze PFAS mixtures. Among adolescents, 38.7% had at least one persistent infection while 14.9% had two or more; among adults, these percentages were 48.0% and 19.7%. Each PFAS was individually associated with significantly higher pathogen burdens and the most pronounced associations were observed in adolescents [e.g., among adolescents, a doubling of PFOS was associated with 30% (95% CI: 25–36%) higher pathogen burden]. Quantile g-computation revealed PFAS mixtures as a whole were also associated with higher pathogen burdens. Taken together, these results suggest PFAS exposure may increase susceptibility to and foster the clustering of persistent infections, particularly among adolescents. Since persistent infections are important contributors to long-term health, prospective data are needed to confirm these findings.
Afficher plus [+] Moins [-]Effect of C/N substrates for enhanced extracellular polymeric substances (EPS) production and Poly Cyclic Aromatic Hydrocarbons (PAHs) degradation
2021
Premnath, N. | Mohanrasu, K. | Guru Raj Rao, R. | Dinesh, G.H. | Siva Prakash, G. | Pugazhendhi, Arivalagan | Jeyakanthan, J. | Govarthanan, Muthusamy | Kumar, Ponnuchamy | Arun, A.
Extracellular Polymeric Substances (EPS) influenced Poly Cyclic Aromatic Hydrocarbons (PAHs) degrading Klebsiella pneumoniae was isolated from the marine environment. To increase the EPS production by Klebsiella pneumoniae, several physicochemical parameters were tweaked such as different carbon sources (arabinose, glucose, glycerol, lactose, lactic acid, mannitol, sodium acetate, starch, and sucrose at 20 g/L), nitrogen sources (ammonium chloride, ammonium sulphate, glycine, potassium nitrate, protease peptone and urea at 2 g/L), different pH, carbon/nitrogen ratio, temperature, and salt concentration were examined. Maximum EPS growth and biodegradation of Anthracene (74.31%), Acenaphthene (67.28%), Fluorene (62.48%), Naphthalene (57.84%), and mixed PAHs (55.85%) were obtained using optimized conditions such as glucose (10 g/L) as carbon source, potassium nitrate (2 g/L) as the nitrogen source at pH 8, growth temperature of 37 °C, 3% NaCl concentration and 72 h incubation period. The Klebsiella pneumoniae biofilm architecture was studied by confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM). The present study demonstrates the EPS influenced PAHs degradation of Klebsiella pneumoniae.
Afficher plus [+] Moins [-]Protective effect of Urtica dioica in induced neurobehavioral changes, nephrotoxicity and hepatotoxicity after chronic exposure to potassium bromate in rats
2021
Dhouibi, Raouia | Affes, Hanen | Ben Salem, Maryem | Charfi, Slim | Marekchi, Rim | Hammami, Serria | Zeghal, Khaled | Ksouda, Kamilia
Chronic exposure to potassium bromate (KBrO₃), a toxic halogen in the environment, has become a global problem of public health. The current study aims to elucidate for the first time the effect of Urtica dioica (UD) on behavioural changes, oxidative stress, and histopathological changes induced by KBrO₃ in the cerebellum, kidney, liver and other organs of adult rats.The rats were divided into four groups: group 1 served as a control received physiological serum, Group 2 received KBrO₃ (2 g/L of drinking water), group 3 received KBrO₃ and Urtica dioica (100 mg/kg), and group 4 received KBrO₃ and Urtica dioica (400 mg/kg). We then measured behavioural changes, oxidative stress, and biochemical and histological changes in the cerebellum, liver, kidney and others organs in these rats. After 30 days of treatment, the animals were sacrificed.We observed significant behavioural changes in KBrO₃-exposed rats. When investigating redox homeostasis in the cerebellum, we found that mice treated with KBrO₃ had increased lipid peroxidation and protein oxidation in the cerebellum. In addition, it inhibits hepatic and lipid peroxidation (malondialdehyde), advanced oxidation protein product (AOPP), attenuates KBrO₃-mediated enzyme depletion, catalase, superoxide dismutase, glutathione peroxidase enzymatic and antioxidant activities in the liver and kidney. Rats that were co-managed with Urtica dioica at the high portion of 400 mg/kg indicated a higher effect than that treated with the low dose of 100 mg/kg practically in all the tests carried out.Our results demonstrate that Urtica dioica is a potential therapeutic agent for oxidative stress associated with neurodegenerative diseases.
Afficher plus [+] Moins [-]Shedding light on toxicity of SARS-CoV-2 peptides in aquatic biota: A study involving neotropical mosquito larvae (Diptera: Culicidae)
2021
Mendonça-Gomes, Juliana Moreira | Charlie-Silva, Ives | Guimarães, Abraão Tiago Batista | Estrela, Fernanda Neves | Calmon, Marilia Freitas | Miceli, Rafael Nava | Sanches, Paulo R.S. | Bittar, Cíntia | Rahal, Paula | Cilli, Eduardo M. | Ahmed, Mohamed Ahmed Ibrahim | Vogel, Christoph F.A. | Malafaia, Guilherme
Knowledge about how the COVID-19 pandemic can affect aquatic wildlife is still extremely limited, and no effect of SARS-CoV-2 or its structural constituents on invertebrate models has been reported so far. Thus, we investigated the presence of the 2019-new coronavirus in different urban wastewater samples and, later, evaluated the behavioral and biochemical effects of the exposure of Culex quinquefasciatus larvae to two SARS-CoV-2 spike protein peptides (PSPD-2002 and PSPD-2003) synthesized in our laboratory. Initially, our results show the contamination of wastewater by the new coronavirus, via RT-qPCR on the viral N1 gene. On the other hand, our study shows that short-term exposure (48 h) to a low concentration (40 μg/L) of the synthesized peptides induced changes in the locomotor and the olfactory-driven behavior of the C. quinquefascitus larvae, which were associated with increased production of ROS and AChE activity (cholinesterase effect). To our knowledge, this is the first study that reports the indirect effects of the COVID-19 pandemic on the larval phase of a freshwater invertebrate species. The results raise concerns at the ecological level where the observed biological effects may lead to drastic consequences.
Afficher plus [+] Moins [-]Uncertainty quantification and atmospheric source estimation with a discrepancy-based and a state-dependent adaptative MCMC
2021
Albani, Roseane A.S. | Albani, Vinicius V.L. | Migon, Helio dos Santos | Silva Neto, Antônio J.
We address the source characterization of atmospheric releases using adaptive strategies in Bayesian inference in combination with the numerical solution of the dispersion problem by a stabilized finite element method and uncertainty quantification in the measurements. The adaptive techniques accelerate the convergence of Monte Carlo Markov Chain (MCMC) algorithms, leading to accurate reconstructions of the source parameters. Such accuracy is illustrated by the comparison with results from previous works. Moreover, the technique used to simulate the corresponding dispersion problem allowed us to introduce relevant meteorological information. The uncertainty quantification also improves the quality of reconstructions. Numerical examples using data from the Copenhagen experimental campaign illustrate the effectiveness of the proposed methodology. We found errors in reconstructions ranging from 0.11% to 8.67% of the size of the search region, which is similar to results found in previous works using deterministic techniques, with comparable computational time.
Afficher plus [+] Moins [-]Reduction in VOC emissions by intermittent aeration in bioreactor landfills with gas-water joint regulation
2021
Chu, Yi-Xuan | Wang, Jing | Tian, Guangming | He, Ruo
Landfill mining and reclamation is a new strategy for addressing the lack of space available for new landfills and realizing the sustainable development of landfills. A gas-water joint bioreactor landfill is regulated by injecting water and/or recirculating leachate, and a blasting aeration system to optimize waste stabilization. In this study, four landfill reactors were constructed to investigate the effects of ventilation methods, including continuous (20 h d⁻¹) and intermittent aeration (4 h d⁻¹ in continuous or 2-h aeration per 12 h, twice a day), on the degradation of organic matter and volatile organic compound (VOC) emissions in comparison with traditional landfills. A total of 62 VOCs were detected in the landfill reactors. Among them, halogenated compounds had the highest abundance (39.8–65.4 %), followed by oxygenated compounds, alkanes and alkenes, and aromatic compounds. Both intermittent and continuous aeration could accelerate the degradation of landfilled waste and increase the volatilization rate of VOCs. Compared with intermittent aeration, the degradation of landfilled waste was more quickly in the landfill reactor with continuous aeration. However, intermittent aeration could create anaerobic-anoxic-aerobic conditions, which were conducive to the growth and metabolism of anaerobic and aerobic microorganisms in landfills and thereby reduced more than 63.4 % of total VOC emissions from the landfill reactor with continuous aeration. Moreover, intermittent aeration could reduce the ventilation rate and decrease the cost of aeration by 80 % relative to continuous aeration. Firmicutes, Bacteroidetes, Proteobacteria and Tenericutes predominated in the landfill reactors. The environmental variables including organic matter and VOCs concentrations had significant influences on microbial community structure in the landfilled waste. These findings indicated that intermittent aeration was an effective way to accelerate the stabilization of landfilled waste and reduce the cost and environmental risks in bioreactor landfills with gas-water joint regulation.
Afficher plus [+] Moins [-]A 150-year record of black carbon (soot and char) and polycyclic aromatic compounds deposition in Lake Phayao, north Thailand
2021
Han, Yongming | Bandowe, Benjamin A Musa | Schneider, Tobias | Pongpiachan, Siwatt | Ho, Steven Sai Hang | Wei, Chong | Wang, Qiyuan | Xing, Li | Wilcke, Wolfgang
An improved understanding of the historical variation in the emissions and sources (biomass burning, BB vs. fossil fuel, FF combustion) of soot and char, the two components of black carbon (BC), and polycyclic aromatic compounds (PACs) may help in assessing the environmental effects of the Atmospheric Brown Cloud (ABC) in SE Asia. We therefore determined historical variations of the fluxes of soot, char, and PACs (24 polycyclic aromatic hydrocarbons (PAHs), 12 oxygenated PAHs (OPAHs), and 4 azaarenes) in a dated sediment core (covering the past ∼150 years) of Phayao Lake in Thailand. The soot fluxes have been increasing in recent times, but at a far lower rate than previously estimated based on BC emission inventories. This may be associated with a decreasing BB contribution as indicated by the decreasing char fluxes from old to young sediments. The fluxes of high- and low-molecular-weight (HMW and LMW) PAHs, OPAHs, and azaarenes all sharply increased after ∼1980, while the ΣLMW-/ΣHMW-PAHs ratios decreased, further supporting the reduction in BB contribution at the expense of increasing FF combustion emissions. We also suggest that the separate record of char and soot, which has up to now not been done in aerosol studies, is useful to assess the environmental effects of ABC because of the different light-absorbing properties of these two BC components. Our results suggest that besides the establishment of improved FF combustion technology, BB must be further reduced in the SE Asian region in order to weaken the ABC haze.
Afficher plus [+] Moins [-]Green remediation of toxic metals contaminated mining soil using bacterial consortium and Brassica juncea
2021
Jeyasundar, Parimala Gnana Soundari Arockiam | Ali, Amjad | Azeem, Muhammad | Li, Yiman | Guo, Di | Sikdar, Ashim | Abdelrahman, Hamada | Kwon, Eilhann | Antoniadis, Vasileios | Mani, Vellingiri Manon | Shaheen, Sabry M. | Rinklebe, Jörg | Zhang, Zengqiang
Microorganism-assisted phytoremediation is being developed as an efficient green approach for management of toxic metals contaminated soils and mitigating the potential human health risk. The capability of plant growth promoting Actinobacteria (Streptomyces pactum Act12 - ACT) and Firmicutes (Bacillus subtilis and Bacillus licheniformis - BC) in mono- and co-applications (consortium) to improve soil properties and enhance phytoextraction of Cd, Cu, Pb, and Zn by Brassica juncea (L.) Czern. was studied here for the first time in both incubation and pot experiments. The predominant microbial taxa were Proteobacteria, Actinobacteria and Bacteroidetes, which are important lineages for maintaining soil ecological activities. The consortium improved the levels of alkaline phosphatase, β-D glucosidase, dehydrogenase, sucrase and urease (up to 33%) as compared to the control. The bacterial inoculum also triggered increases in plant fresh weight, pigments and antioxidants. The consortium application enhanced significantly the metals bioavailability (DTPA extractable) and mobilization (acid soluble fraction), relative to those in the unamended soil; therefore, significantly improved the metals uptake by roots and shoots. The phytoextraction indices indicated that B. juncea is an efficient accumulator of Cd and Zn. Overall, co-application of ACT and BC can be an effective solution for enhancing phytoremediation potential and thus reducing the potential human health risk from smelter-contaminated soil. Field studies may further credit the understanding of consortium interactions with soil and different plant systems in remediating multi-metal contaminated environments.
Afficher plus [+] Moins [-]Eco-friendly synthesis of lignin mediated silver nanoparticles as a selective sensor and their catalytic removal of aromatic toxic nitro compounds
2021
Lee, Seung Jun | Begildayeva, Talshyn | Yeon, Sanghun | Naik, Shreyanka Shankar | Ryu, Hakseung | Kim, Tae Ho | Choi, Myong Yong
The development of an eco-friendly and reliable process for the production of nanomaterials is essential to overcome the toxicity and exorbitant cost of conventional methods. As such, a facile and green synthesis method is introduced for the preparation of lignin mediated silver nanoparticles (L-Ag NPs). This is produced by reducing Ag precursors using lignin biopolymers which are formulated by pulsed laser irradiation and an ultrasonication process. Lignin operates as both a reducing and stabilizing agent. The various analytical techniques of ultraviolet–visible spectroscopy, transmission electron microscope and X-ray diffractometer studies were employed to verify the formation of non-aggregated spherical L-Ag NPs with an average size as small as 7–8 nm. The selective sensing capability of the synthesized L-Ag NPs was examined for the detection of hydrogen peroxide and mercury ions in an aqueous environment. Furthermore, the superior catalytic performance of L-Ag NPs was demonstrated by the rapid conversion of toxic 4-nitrophenol and nitrobenzene as targeted pollutants to the corresponding amino compounds. A plausible catalytic reduction mechanism for the removal of toxic nitro-organic pollutants over L-Ag NPs is proposed. This research coincides with existing studies and affirms that L-Ag NPs are an effective sensor that be applied as a catalytic material within environmental remediation and also alternative biomedical applications.
Afficher plus [+] Moins [-]Simultaneous enantioselective analysis of illicit drugs in wastewater and surface water by chiral LC–MS/MS: A pilot study on a wastewater treatment plant and its receiving river
2021
Wang, Weimin | Guo, Changsheng | Chen, Like | Qiu, Ziwen | Yin, Xingxing | Xu, Jian
An enantioselective method for quantifying amphetamine-type chiral illicit drugs (CIDs) in wastewater and surface water was developed, validated, and applied to samples from a wastewater treatment plant (WWTP) and its effluent-receiving river in Beijing, China. Water samples were subjected to solid-phase extraction (SPE) and then quantified via liquid chromatography–tandem mass spectrometry. The enantioseparation of CIDs was performed with a CHIRALPAK CBH column. Chromatographic parameters, including mobile phase composition and flow rates, were tested to identify the satisfactory enantiomeric resolution. The SPE method was optimized by evaluating variables, including SPE cartridge types, extraction solvents, and solvent volumes. The Oasis HLB sorbent showed good performance with recoveries exceeding 60% and matrix effects ranging from −19.6% to 26.6% for most target enantiomers, except for norephedrine (NE), in three different aquatic matrixes. The established method was superior to previously reported methods and had a low limit of detection, low limit of quantification, and short runtime (<45 min). The repeatability and reproducibility of the method reached 19.1% and 17.8%, respectively. The method was successfully utilized to monitor the daily variations in CIDs in the influent, effluent, and effluent-receiving river of a WWTP in Beijing over 1 week. The common occurrence of 1 R,2 S-(−)-ephedrine (1 R,2 S-(−)-EPH), 1 S,2 S-(+)-pseudoephedrine (1 S,2 S-(+)-PEPH), R-(−)-methamphetamine (METH), and S-(+)-METH in wastewater samples was observed. Ephedrines (1 R,2 S-(−)-EPH and 1 S,2 S-(+)-PEPH) were the most abundant CIDs in the influent, effluent, upstream, and downstream samples with concentrations of 725.8 ± 181.2 ng/L, 22.9 ± 4.9 ng/L, 12.96 ± 0.79 ng/L, and 11.6 ± 6.7 ng/L, respectively. METH was detectable in most water samples and was present in excess in S-enantiomer form in the influent and in R-enantiomer form in the effluent and surface water. R-(−)-MDMA was detected at a concentration of up to 2.4 ng/L in the influent. The metabolites norketamine (NK), amphetamine(AMP), MDA, and NE were not detected in water samples given the low concentration of their parent drugs.
Afficher plus [+] Moins [-]