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Perchlorate has been described as an emerging pollutant that compromises water sources and human health. In this study, a new electrotrophic perchlorate reducing microorganism (EPRM) isolated from the Atacama Desert, Dechloromonas sp. CS-1, was evaluated for perchlorate removal in water in a bioelectrochemical reactor (BER) with a chemically modified electrode. BERs were operated for 17 days under batch mode conditions with an applied potential of -500 mV vs. Ag/AgCl. Surface analysis (i.e., SEM, XPS, FT-IR, RAMAN spectroscopy) on the modified electrode demonstrated heterogeneous transformation of the carbon fibers with the incorporation of nitrogen functional groups and the oxidation of the carbonaceous material. The BERs with the modified electrode and the presence of the EAM reached high cathodic efficiency (90.79 ± 9.157%) and removal rate (0.34 ± 0.007 mol m-3-day) compared with both control conditions. The observed catalytic enhancement of CS-1 was confirmed by a reduction in the charge transfer resistance obtained by electrochemical impedance spectroscopy (EIS). Finally, an electrochemical kinetic study revealed an eight-electron perchlorate bioreduction reaction at -638.33 ± 24.132 mV vs. Ag/AgCl. Therefore, our results show the synergistic effect of EPRM and chemically modified electrodes on perchlorate removal in a BER.
Assuntos
Nitrogênio , Percloratos , Humanos , Espectroscopia de Infravermelho com Transformada de Fourier , Nitrogênio/metabolismo , Eletrodos , OxirreduçãoRESUMO
This study highlights the importance of following a strict protocol for Nafion membrane pretreatment for electrochemical nitrogen reduction reaction experiments. Atmospheric ammonia pollution can be introduced to the experimental setup through membranes and interpreted falsely as catalysis product from N2 . The sources of ammonia contamination vary drastically between locations worldwide and even within the same location between days depending on temperature, wind direction, fertilizer use, and manure accumulation in its vicinity. The study shows that significant amounts of ammonium is accumulated in the membranes after commonly practiced pretreatment methods, where the amount depends on the ammonia concentration in the surrounding of the experiment. Therefore, we introduce a new pretreatment method which removes all the ammonium in the membrane. The membranes can be stored for several days but a short final step in the method needs to be carried out right before NRR experiments.
Assuntos
Amônia/análise , Polímeros de Fluorcarboneto/química , Nitrogênio/química , Técnicas Eletroquímicas , Oxirredução , TemperaturaRESUMO
BACKGROUND: Williams syndrome (WS) is a rare genetic disorder associated with a high prevalence of anxiety disorders. Evidence-based pharmacologic treatments for anxiety in WS are lacking. The purpose of this study is to provide naturalistic data on the use of buspirone for the treatment of anxiety in WS. RESEARCH DESIGN AND METHODS: Medical records of 24 individuals with Williams syndrome (ages 7-47 years) and anxiety who received treatment with buspirone were reviewed. Treatment response to buspirone was rated by assigning a retrospective Clinical Global Impression Improvement subscale (CGI-I) score. RESULTS: Twenty-three of 24 (96%) patients completed at least a 16-week treatment course with buspirone. Sixteen patients (67%; 95% CI 47%, 82%) were treatment responders (CGI-I ≤ 2). Only 1 (4%) patient discontinued buspirone due to a treatment-emergent side effect (nausea and vomiting). The most common side effect was nausea (13%). Twenty (84%) patients remained on buspirone at the time of their most recent follow-up visit. CONCLUSIONS: In this retrospective study, the majority of patients responded to a 16-week course of buspirone. Prospective studies are warranted to further assess the efficacy and tolerability of buspirone for anxiety in WS.
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Ansiolíticos , Síndrome de Williams , Humanos , Buspirona/efeitos adversos , Estudos Retrospectivos , Síndrome de Williams/tratamento farmacológico , Síndrome de Williams/induzido quimicamente , Transtornos de Ansiedade/tratamento farmacológico , Ansiedade/tratamento farmacológico , Ansiedade/etiologia , Ansiolíticos/efeitos adversos , Náusea/induzido quimicamente , Método Duplo-CegoRESUMO
Sex-based differences in the prevalence of autism spectrum disorder (ASD) are well-documented, with a male-to-female ratio of approximately 4:1. The clinical presentation of the core symptoms of ASD can also vary between sexes. Previously, positron emission tomography (PET) studies have identified alterations in the in vivo levels of translocator protein (TSPO)-a mitochondrial protein-in primarily or only male adults with ASD, with our group reporting lower TSPO relative to whole brain mean in males with ASD. However, whether in vivo TSPO levels are altered in females with ASD, specifically, is unknown. This is the first pilot study to measure in vivo TSPO in the brain in adult females with ASD using [11C]PBR28 PET-magnetic resonance imaging (MRI). Twelve adult females with ASD and 10 age- and TSPO genotype-matched controls (CON) completed one or two [11C]PBR28 PET-MRI scans. Females with ASD exhibited elevated [11C]PBR28 standardized uptake value ratio (SUVR) in the midcingulate cortex and splenium of the corpus callosum compared to CON. No brain area showed lower [11C]PBR28 SUVR in females with ASD compared to CON. Test-retest over several months showed stable [11C]PBR28 SUVR across time in both groups. Elevated regional [11C]PBR28 SUVR in females with ASD stand in stark contrast to our previous findings of lower regional [11C]PBR28 SUVR in males with ASD. Preliminary evidence of regionally elevated mitochondrial protein TSPO relative to whole brain mean in ASD females may reflect neuroimmuno-metabolic alterations specific to females with ASD.
Assuntos
Transtorno do Espectro Autista , Encéfalo , Tomografia por Emissão de Pósitrons , Receptores de GABA , Humanos , Feminino , Transtorno do Espectro Autista/metabolismo , Transtorno do Espectro Autista/diagnóstico por imagem , Projetos Piloto , Receptores de GABA/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Adulto , Adulto Jovem , Encéfalo/metabolismo , Encéfalo/diagnóstico por imagem , Caracteres Sexuais , Adolescente , MasculinoRESUMO
The use of antibiotics in the livestock sector has resulted in the entry of these drugs into the soil matrix through the disposal of manure as an organic amendment. To define the fate of these drugs, it is necessary to evaluate kinetic aspects regarding transport in the soil-solution. The aim of this paper is to evaluate the adsorption kinetic parameters of Ciprofloxacin (CIPRO) in Ultisol and Andisol soil which allows obtaining main kinetic parameters (pseudo-first and pseudo-second order models) and to establish the solute transport mechanism by applying kinetic models such as the Elovich equation, Intraparticle diffusion (IPD) and, the Two-site non-equilibrium models (TSNE). The adsorption kinetics of this fluoroquinolone (FQ), on both soils derived from volcanic ashes, is developed using electrochemical techniques for their determination. The experimental amount of CIPRO adsorbed over time (Qt) data best fit with the pseudo-second order kinetic models; R2 = 0.9855, Æ = 10.17% and R2 = 0.9959, Æ = 10.77% for Ultisol and Andisol, respectively; and where CIPRO adsorption was considered time dependent for both soils but the lower adsorption capacity in Ultisol; with 17.6 ± 2.8 µmol g-1; which could mean a greater risk in environmental. Subsequently, applying models to describe solute transport mechanisms showed differences in the CIPRO adsorption extent for the fast and slow phases. Adsorption isotherms were evaluated, where Ultisol occurs on heterogenous sites as multilayers and Andisol by monolayer with similar Qmax. Finally, the socio-economic impact of antibiotic usage is presented, giving the importance of antibiotics in the livestock sector and their effects on human health.
Assuntos
Ciprofloxacina , Solo , Humanos , Adsorção , Antibacterianos , Fatores Socioeconômicos , CinéticaRESUMO
Williams syndrome (WS) is a genetic disorder affecting multiple organ systems. Cardinal features include cardiovascular disease, distinct facies, and a unique cognitive profile characterized by intellectual disability, hypersociability, and visuospatial weaknesses. Here, we synthesize neuroimaging research in WS with a focus on how the current literature and future work may be leveraged to improve health and quality of life in WS. More than 80 neuroimaging studies in WS have been conducted, the vast majority of which have focused on identifying morphometric brain differences. Aside from decreased volume of the parieto-occipital region and increased cerebellar volume, morphometric findings have been variable across studies. fMRI studies investigating the visuospatial deficit have identified dorsal stream dysfunction and abnormal activation of the hippocampal formation. Minimal work has been done using PET or MRS. Future approaches that conduct neuroimaging in tandem with clinical phenotyping, utilize novel imaging techniques to visualize brain vasculature or provide biochemical and molecular information, and include more homogenous age groups across the lifespan, have significant potential to advance clinical care.
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This study evaluated the electrochemical capacity of four perchlorate-reducing microorganisms (PRMs) isolated from an Altiplanic Andean watershed naturally pressured with perchlorate. Three-electrode electrochemical cells were used to test the electrochemical activity of the obtained isolates. Electrochemical evaluation (i.e., cyclic voltammetry, electrochemical impedance spectroscopy, chronoamperometry) revealed that two isolates identified as Dechloromonas sp. CS-1 and Clostridioides sp. CS-2 are electrochemically active PRMs. Bacterial isolates exhibiting cathodic peaks at -651 mV and -303 mV (vs. Ag/AgCl) for CS-1 and CS-2, respectively. Electrotrophic perchlorate removal was demonstrated by a 6-days chronoamperometry with removal rates of 27 and 17 mg L-1 day-1 and cathodic efficiencies of 93% and 45%, for CS-1 and CS-2, respectively. Chemical and electrochemical results suggest two different mechanisms of electrotrophic perchlorate removal, a complete eight-electron bio-reduction (i.e., perchlorate to chloride) for CS-1 and a partial two-electron bio-reduction (i.e., perchlorate to chlorate) for CS-2. The observed differences could be linked to their enzymatic differences, as in their membrane compositions. Thus, the results of this work increase the limited number of known electrotrophic microorganisms and expand the application of bioelectrochemical systems to develop new perchlorate treatment and remediation technologies.
Assuntos
Bioprospecção , Percloratos , Eletrodos , Elétrons , OxirreduçãoRESUMO
Microbially influenced corrosion (MIC) is an aggressive type of corrosion that occurs in aquatic environments and is sparked by the development of a complex biological matrix over a metal surface. In marine environments, MIC is exacerbated by the frequent variability in environmental conditions and the typically high diversity of microbial communities; hence, local and in situ studies are crucial to improve our understanding of biofilm composition, biological interactions among its members, MIC characteristics, and corrosivity. Typically, material performance and anticorrosion strategies are evaluated under controlled laboratory conditions, where natural fluctuations and gradients (e.g., light, temperature, and microbial composition) are not effectively replicated. To determine whether MIC development and material deterioration observed in the laboratory are comparable to those that occur under service conditions (i.e., field conditions), we used two testing setups, in the lab and in the field. Stainless steel (SS) AISI 316L coupons were exposed to southeastern Pacific seawater for 70 days using (i) acrylic tanks in a running seawater laboratory and (ii) an offshore mooring system with experimental frames immersed at two depths (5 and 15 m). Results of electrochemical evaluation, together with those of microbial community analyses and micrographs of formed biofilms, demonstrated that the laboratory setup provides critical information on the early biofilm development process (days), but the information gathered does not predict deterioration or biofouling of SS surfaces exposed to natural conditions in the field. Our results highlight the need to conduct further research efforts to understand how laboratory experiments may better reproduce field conditions where applications are to be deployed, as well as to improve our understanding of the role of eukaryotes and the flux of nutrients and oxygen in marine MIC events.
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Antimicrobial compounds are found in a range of environments as pollutants. Here, we evaluated the influence of two common anions, NO3- and PO43-, on ciprofloxacin adsorption on humic acid/ferrihydrite composite (HA-DIG/Fh), synthetic ferrihydrite (Fh), and humic acid (HA-DIG) under controlled pH (7.0), ionic strength (0.1â¯M) and temperature (25⯰C). All materials were characterized by isoelectric point (IEP), while the composite and the iron oxide were characterized by Mössbauer spectroscopy. Kinetic and isotherm adsorption studies were carried out using cyclic voltammetry (in KH2PO4) and square wave voltammetry (in KNO3). The application of kinetic models for both anions revealed Fh to fit to a pseudo second order model (R2â¯=â¯0.941); while HA-DIG (R2â¯=â¯0.950) and HA-DIG/Fh (R2â¯=â¯0.993) were fitted to pseudo first order models. The adsorption results showed a high dependency electrolyte, especially in Fh, where different shape curves (H-type in KNO3 and C-type in KH2PO4) and maximum experimental adsorbed amount Cm were observed. This finding is supported by the distinct IEP values and change in sign of surface charge between the two ions. Finally, results suggest that HA-DIG could be potentially used in environmental remediation to remove antibiotics from natural matrices, though the risk of antibiotic transportation increased with depth in the soil profile.
Assuntos
Antibacterianos/química , Ciprofloxacina/química , Compostos Férricos/química , Substâncias Húmicas , Adsorção , Cinética , Nitratos/química , Fosfatos/química , Eletricidade Estática , Propriedades de SuperfícieRESUMO
Chlorate has been described as an emerging pollutant that compromises water sources. In this study, bioelectrochemical reactors (BERs) using Dechloromonas agitata CKB, were evaluated as a sustainable alternative for chlorate removal. BERs were operated under flow-recirculation and batch modes with an applied cell-voltage of 0.44 V over a resistance of 1 kΩ. Results show chlorate removal up to 607.288 mg/L. After 115 days, scanning electron microscopy showed biofilm development over the electrodes, and electrochemical impedance spectroscopy confirmed the biocatalytic effect of CKB. The theoretical chlorate bioreduction potential (ε° = 0.792 V) was proven, and a kinetic study indicated that 6 electrons were involved in the reduction mechanism. Finally, a hypothetical bioelectrochemical mechanism for chlorate reduction in a BER was proposed. This research expands upon current knowledge of novel electrochemically active microorganisms and widens the scope of BER applications for chlorate removal.