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1.
J Public Health Manag Pract ; 24(2): e10-e17, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28257404

RESUMO

CONTEXT: Lead is a preventable environmental toxin that has been previously associated with deficits in cognition, academic performance, attention, and behavior in children. Very few studies, however, have examined the relationship between exposure to lead and documented developmental disabilities. OBJECTIVE: This study examined the relative risk of lead exposure on developmental disabilities in preschool-aged children. DESIGN: A statewide lead surveillance data set containing blood lead level (BLL) was integrated with another statewide data set containing developmental disability classifications for special education placement for preschool-aged children. PARTICIPANTS: The participants were the 85 178 children (average age 2.6 years) whose records in both data sets were able to be linked. Forty-six percent of the participants had an identified developmental disability. MAIN OUTCOME MEASURE: Developmental disability classification served as the main outcome measure. RESULTS: A high BLL, defined as 5 µg/dL or more, was associated with significantly increased risk for developmental disabilities (risk ratio [RR] = 1.04; 95% CI = 1.01-1.08), particularly intellectual disability (RR = 1.58, 95% CI = 1.10-2.25) and developmental delay (DD; RR = 1.11, 95% CI = 1.06-1.17). CONCLUSIONS: The results of this study are consistent with previous research identifying an association between lead exposure and numerous intellectual and educational outcomes and demonstrate that high BLL is associated with meeting eligibility criteria for developmental disabilities in young children. Continued research, surveillance, and prevention efforts are needed to further reduce the negative impacts of lead on individuals and society. Reducing or eliminating lead exposure would improve outcomes for individual children (eg, better academic performance) and reduce the burden to society (eg, lower enrollments in special education systems).


Assuntos
Deficiências do Desenvolvimento/etiologia , Chumbo/efeitos adversos , Pré-Escolar , Deficiências do Desenvolvimento/sangue , Deficiências do Desenvolvimento/epidemiologia , Exposição Ambiental/efeitos adversos , Feminino , Humanos , Chumbo/análise , Chumbo/sangue , Masculino
2.
Am J Public Health ; 103(6): 1058-66, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23597356

RESUMO

OBJECTIVES: We evaluated Legacy for Children, a public health strategy to improve child health and development among low-income families. METHODS: Mothers were recruited prenatally or at the birth of a child to participate in Legacy parenting groups for 3 to 5 years. A set of 2 randomized trials in Miami, Florida, and Los Angeles, California, between 2001 and 2009 assessed 574 mother-child pairs when the children were 6, 12, 24, 36, 48, and 60 months old. Intent-to-treat analyses from 12 to 60 months compared groups on child behavioral and socioemotional outcomes. RESULTS: Children of mothers in the intervention group were at lower risk for behavioral concerns at 24 months and socioemotional problems at 48 months in Miami, and lower risk for hyperactive behavior at 60 months in Los Angeles. Longitudinal analyses indicated that children of intervention mothers in Miami were at lower risk for behavior problems from 24 to 60 months of age. CONCLUSIONS: Randomized controlled trials documented effectiveness of the Legacy model over time while allowing for implementation adaptations by 2 different sites. Broadly disseminable, parent-focused prevention models such as Legacy have potential for public health impact. These investments in prevention might reduce the need for later intervention strategies.


Assuntos
Transtornos do Comportamento Infantil/epidemiologia , Proteção da Criança , Promoção da Saúde/métodos , Pobreza , Avaliação de Programas e Projetos de Saúde , Ajustamento Social , Adulto , Fatores Etários , Pré-Escolar , Florida , Humanos , Lactente , Modelos Logísticos , Los Angeles , Relações Mãe-Filho , Poder Familiar , Adulto Jovem
3.
Front Microbiol ; 14: 1199286, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38075904

RESUMO

Many factors affect the performance of microbial fuel cells (MFCs). Considerable attention has been given to the impact of cell configuration and materials on MFC performance. Much less work has been done on the impact of the anode microbiota, particularly in the context of using complex substrates as fuel. One strategy to improve MFC performance on complex substrates such as wastewater, is to pre-enrich the anode with known, efficient electrogens, such as Geobacter spp. The implication of this strategy is that the electrogens are the limiting factor in MFCs fed complex substrates and the organisms feeding the electrogens through hydrolysis and fermentation are not limiting. We conducted a systematic test of this strategy and the assumptions associated with it. Microbial fuel cells were enriched using three different substrates (acetate, synthetic wastewater and real domestic wastewater) and three different inocula (Activated Sludge, Tyne River sediment, effluent from an MFC). Reactors were either enriched on complex substrates from the start or were initially fed acetate to enrich for Geobacter spp. before switching to synthetic or real wastewater. Pre-enrichment on acetate increased the relative abundance of Geobacter spp. in MFCs that were switched to complex substrates compared to MFCs that had been fed the complex substrates from the beginning of the experiment (wastewater-fed MFCs - 21.9 ± 1.7% Geobacter spp.; acetate-enriched MFCs, fed wastewater - 34.9 ± 6.7% Geobacter spp.; Synthetic wastewater fed MFCs - 42.5 ± 3.7% Geobacter spp.; acetate-enriched synthetic wastewater-fed MFCs - 47.3 ± 3.9% Geobacter spp.). However, acetate pre-enrichment did not translate into significant improvements in cell voltage, maximum current density, maximum power density or substrate removal efficiency. Nevertheless, coulombic efficiency (CE) was higher in MFCs pre-enriched on acetate when complex substrates were fed following acetate enrichment (wastewater-fed MFCs - CE = 22.0 ± 6.2%; acetate-enriched MFCs, fed wastewater - CE =58.5 ± 3.5%; Synthetic wastewater fed MFCs - CE = 22.0 ± 3.2%; acetate-enriched synthetic wastewater-fed MFCs - 28.7 ± 4.2%.) The relative abundance of Geobacter ssp. and CE represents the average of the nine replicate reactors inoculated with three different inocula for each substrate. Efforts to improve the performance of anodic microbial communities in MFCs utilizing complex organic substrates should therefore focus on enhancing the activity of organisms driving hydrolysis and fermentation rather the terminal-oxidizing electrogens.

4.
J Cell Physiol ; 227(2): 578-86, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21448924

RESUMO

In this study we investigated the effect of glucose on GSK3ß and ß-catenin expression and the involvement of the N-linked glycosylation and hexosamine pathways in the Wnt canonical pathway in response to in vitro conditions resembling normoglycemia (5 mmol) and hyperglycemia (20 mmol) in the metastatic breast cancer-derived cell line MDA-MB-231. We also investigated the relationship between this circuitry and the thioredoxin-interacting protein (TXNIP) regulation that seems to be related. MDA-MB-231 cells were grown either in 5 or 20 mM glucose chronically prior to plating. For glucose shift (5/20), cells were plated in 5 mM glucose and shifted to 20 mM at time 0. Both protein and mRNA levels for GSK3ß but only the protein expression for ß-catenin, were increased in response to high glucose. Furthermore, we assessed the response of GSK3ß, ß-catenin, and TXNIP to inhibition of the N-linked glycosylation, hexosamine, and Wnt pathways. Wnt signaling pathway activation was validated by specific reporter assay. We show that high levels of glucose regulate mRNA and protein expression of GSK3ß, and consequently higher levels of activated ß-catenin protein, which locates to the nucleus and is associated with increased levels of cyclin D1 expression. This event coincides with increased level of N-terminal Ser 9 phosphorylation of GSK3ß protein. The inhibition of both the hexosamine pathway and N-linked glycosylation along with Wnt signaling pathway by sFRP1 and DKK1 is associated with significant decrease of the protein levels of GSK3ß, ß-catenin, and TXNIP RNA. Our work illuminates a novel and never described before function of this signaling pathway that relates glucose metabolism with redox regulation mechanism.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas de Transporte/metabolismo , Glucose/metabolismo , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Proteínas de Transporte/genética , Linhagem Celular Tumoral , Ciclina D1/genética , Ciclina D1/metabolismo , Feminino , Regulação Neoplásica da Expressão Gênica/fisiologia , Quinase 3 da Glicogênio Sintase/genética , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Humanos , Transdução de Sinais/fisiologia , Proteínas Wnt/genética , beta Catenina/genética
5.
Environ Sci Technol ; 46(5): 2984-92, 2012 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-22352455

RESUMO

Microbial fuel cells (MFCs) can convert organic compounds directly into electricity by catalytic oxidation, and although MFCs have attracted considerable interest, there is little information on the electricity-generating potential of artificial bacterial biofilms. We have used acetate-fed MFCs inoculated with sediment, with two-chamber bottles and carbon cloth electrodes to deliver a maximum power output of ~175 mW · m(-2) and a stable power output of ~105 mW · m(-2). Power production was by direct transfer of electrons to the anode from bacterial consortia growing on the anode, as confirmed by cyclic voltammetry (CV) and scanning electron microscopy (SEM). Twenty different species (74 strains) of bacteria were isolated from the consortium under anaerobic conditions and cultured in the laboratory, of which 34% were found to be exoelectrogens in single-species studies. Exoelectrogenesis by members of the genera Vibrio , Enterobacter , and Citrobacter and by Bacillus stratosphericus was confirmed, by use of culture-based methods, for the first time. An MFC with a natural bacterial consortium showed higher power densities than those obtained with single strains. In addition, the maximum power output could be further increased to ~200 mW · m(-2) when an artificial consortium consisting of the best 25 exoelectrogenic isolates was used, demonstrating the potential for increased performance and underlying the importance of artificial biofilms for increasing power output.


Assuntos
Bactérias/crescimento & desenvolvimento , Fontes de Energia Bioelétrica/microbiologia , Biofilmes/crescimento & desenvolvimento , Eletricidade , Consórcios Microbianos , Microbiologia da Água , Bactérias/genética , Bactérias/ultraestrutura , DNA Ribossômico/genética , Técnicas Eletroquímicas , Eletrodos , Sedimentos Geológicos/microbiologia , Dados de Sequência Molecular , Filogenia , Especificidade da Espécie
6.
BMC Public Health ; 12: 691, 2012 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-22917446

RESUMO

BACKGROUND: One in five Americans under age 18 lives in a family below the Federal poverty threshold. These more than 15 million children are at increased risk of a wide variety of adverse long-term health and developmental outcomes. The early years of life are critical to short- and long-term health and well-being. The Legacy for ChildrenTM model was developed in response to this need and marries the perspectives of epidemiology and public health to developmental psychology theory in order to better address the needs of children at environmental risk for poor developmental outcomes. METHODS/DESIGN: The Legacy for ChildrenTM group-based parenting intervention model was evaluated as a pair of randomized controlled trials among low-income families in Miami and Los Angeles. The study was designed to allow for site-stratified analysis in order to evaluate each model implementation separately. Evaluation domains include comprehensive assessments of family, maternal, and child characteristics, process outcomes, and prospective programmatic cost. Data collection began prenatally or at birth and continues into school-age. DISCUSSION: The societal costs of poor developmental outcomes are substantial. A concerted effort from multiple sectors and disciplines, including public health, is necessary to address these societal concerns. Legacy uses a public health model to engage parents and promote overall child well-being in families in poverty through rigorous evaluation methodologies and evidence-based intervention strategies. This study collects rich and modular information on maternal and child outcomes, process, and cost that will enable a detailed understanding of how Legacy works, how it can be refined and improved, and how it can be translated and disseminated. Taken together, these results will inform public policy and help to address issues of health disparities among at-risk populations. TRIAL REGISTRATION: NCT00164697.


Assuntos
Continuidade da Assistência ao Paciente/normas , Avaliação de Resultados em Cuidados de Saúde/métodos , Aceitação pelo Paciente de Cuidados de Saúde , Pobreza , Saúde Pública/métodos , Adulto , Feminino , Florida , Habitação/economia , Humanos , Los Angeles , Masculino , Idade Materna , Mães/psicologia , Mães/estatística & dados numéricos , Aceitação pelo Paciente de Cuidados de Saúde/etnologia , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Pobreza/etnologia , Pobreza/psicologia , Pobreza/estatística & dados numéricos , Avaliação de Programas e Projetos de Saúde , Projetos de Pesquisa , Tamanho da Amostra , Fatores Socioeconômicos , Adulto Jovem
7.
Chemosphere ; 288(Pt 2): 132548, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34653487

RESUMO

A microbial electrolysis cell (MEC) fully catalysed by microorganisms is an attractive technology because it incorporates the state-of-the-art concept of converting organic waste to hydrogen with less external energy input than conventional electrolysers. In this work, the impact of the anode feed mode on the production of hydrogen by the biocathode was studied. In the first part, three feed modes and MEC performance in terms of hydrogen production were evaluated. The results showed the highest hydrogen production under the continuous mode (14.6 ± 0.4), followed by the fed-batch (12.7 ± 0.4) and batch (0 L m-2 cathode day-1) modes. On one hand, the continuous mode only increased by 15% even though the hydraulic retention time (HRT) (2.78 h) was lower than the fed-batch mode (HRT 5 h). A total replacement (fed-batch) rather than a constant mix of existing anolyte and fresh medium (continuous) was preferable. On the other hand, no hydrogen was produced in batch mode due to the extensive HRT (24 h) and bioanode starvation. In the second part, the fed-batch mode was further evaluated using a chronoamperometry method under a range of applied cell voltages of 0.3-1.6 V. Based on the potential evolution at the electrodes, three main regions were identified depending on the applied cell voltages: the cathode activation (<0.8 V), transition (0.8-1.1 V), and anode limitation (>1.1 V) regions. The maximum hydrogen production recorded was 12.1 ± 2.1 L m-2 cathode day-1 at 1.0 V applied voltage when the oxidation and reduction reactions at the anode and cathode were optimal (2.38 ± 0.61 A m-2). Microbial community analysis of the biocathode revealed that Alpha-, and Deltaproteobacteria were dominant in the samples with >70% abundance. At the genus level, Desulfovibrio sp. was the most abundant in the samples, showing that these microbes may be responsible for hydrogen evolution.


Assuntos
Eletrólise , Hidrogênio , Eletrodos
8.
Appl Microbiol Biotechnol ; 90(2): 789-98, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21347728

RESUMO

This study determined the influence of substrate degradation on power generation in microbial fuel cells (MFCs) and microbial community selection on the anode. Air cathode MFCs were fed synthetic medium containing different substrates (acetate, glucose and starch) using primary clarifier sewage as source of electroactive bacteria. The complexity of the substrate affected the MFC performance both for power generation and COD removal. Power output decreased with an increase in substrate complexity from 99±2 mWm(-2) for acetate to 4±2 mWm(-2) for starch. The organic matter removal and coulombic efficiency (CE) of MFCs with acetate and glucose (82% of COD removal and 26% CE) were greater than MFCs using starch (60% of COD removal and 19% of CE). The combined hydrolysis-fermentation rate obtained (0.0024 h(-1)) was considerably lower than the fermentation rate (0.018 h(-1)), indicating that hydrolysis of complex compounds limits current output over fermentation. Statistical analysis of microbial community fingerprints, developed on the anode, showed that microbial communities were enriched according to the type of substrate used. Microbial communities producing high power outputs (fed acetate) clustered separately from bacterial communities producing low power outputs (fed complex compounds).


Assuntos
Bactérias/metabolismo , Fontes de Energia Bioelétrica/microbiologia , Fermentação , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos/microbiologia , Meios de Cultura , Eletrodos , Glucose/metabolismo , Hidrólise , Esgotos/microbiologia , Amido/metabolismo
9.
Biosens Bioelectron ; 190: 113392, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34153826

RESUMO

Microbial Fuel Cells (MFCs) operated as biosensors could potentially enable truly low-cost, real-time monitoring of organic loading in wastewaters. The current generated by MFCs has been correlated with conventional measures of organic load such as Biochemical Oxygen Demand (BOD), but much remains to be established in terms of the reliability and applicability of such sensors. In this study, batch-mode and multi-stage, flow-mode MFCs were operated for over 800 days and regularly re-calibrated with synthetic wastewater containing glucose and glutamic acid (GGA). BOD5 calibration curves were obtained by normalising the current measured as a percentage of maximum current. There was little drift between recalibrations and non-linear Hill models of the combined dataset had R2 of 88-95%, exhibiting a stable response over time and across devices. Nonetheless, factors which do affect calibration were also assessed. Increasing external resistance (from 43.5 to 5100 Ω) above the internal resistance determined by polarisation curve decreased the calibration upper limit from 240 to 30 mg/l O2 BOD5. Furthermore, more fermentable carbon sources increased the detection range, as tested with samples of real wastewater and synthetic media containing GGA, glucose-only and glutamic acid-only. Biofilm acclimatisation therefore did not account for differences between aerobic oxygen demand determinations and anaerobic MFC responses; these are likely attributable to competitive processes such as fermentation. This further highlights the potential for MFCs as real-time sensors for organic load monitoring and process control in addition to BOD-compliant measurement systems.


Assuntos
Fontes de Energia Bioelétrica , Técnicas Biossensoriais , Análise da Demanda Biológica de Oxigênio , Calibragem , Reprodutibilidade dos Testes , Águas Residuárias
10.
ACS Appl Mater Interfaces ; 13(3): 4062-4071, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33428393

RESUMO

Aprotic lithium-oxygen batteries currently suffer from poor cyclic stability and low achievable energy density. Herein, gold nanoparticles capped with mercaptosuccinic acid are dispersed in 1.0 M LiClO4/dimethyl sulfoxide (DMSO) as a novel electrolyte for lithium-oxygen batteries. Morphological and electrochemical analyses indicate that film-like amorphous lithium peroxide is formed using the gold nanocolloid electrolyte instead of bulk crystals in battery discharging, which apparently increases the conductivity and accelerates the decomposition kinetics of discharge products in recharging, accompanied by the release of incorporated gold nanoparticles with the decomposition of lithium peroxide into the electrolyte. Experiments and theoretical calculations further demonstrate that the suspended gold nanoparticles in the electrolyte can adsorb some intermediates generated by an oxygen reduction reaction, which effectively alleviates the cleavage of the electrolyte and impedes the corrosion of the lithium anode. As a result, the life span of lithium-oxygen batteries is dramatically increased from 55 to 438 cycles, and the rate performance and full-discharge capacity are also massively enhanced. The battery failure is attributed to the degradation of gold nanocolloid electrolytes, and further studies on improvement of colloid stability during battery cycling are underway.

11.
Sci Total Environ ; 756: 143752, 2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33279191

RESUMO

In this study, an azo dye (Acid Blue 29 or AB29) was efficiently degraded with acetate as co-substrate into less contaminated biodegraded products using an integrated single chamber microbial fuel cell (SMFC)-aerobic bioreactor set-up. The decolorization efficiencies were varied from 91 ± 2% to 94 ± 1.9% and more than 85% of chemical oxygen demand (COD) removal was achieved for all dye concentrations after different operating time. The highest coulombic efficiency (CE) and cell potential were 3.18 ± 0.45% and 287.2 mV, respectively, for SMFC treating 100 mg L-1 of AB29. Electrochemical impedance spectroscopy (EIS) revealed that the anode resistance was 0.3 Ω representing an entirely grown biofilm on the anode surface resulted in higher electron transfer rate. Gas chromatography coupled mass spectrometry (GC-MS) investigation demonstrated that initially biodegradation of AB29 started with the cleavage of the azo bond (-N=N-), resulted the biotransformation into aromatic amines. In successive aerobic treatment stage, these amines were biodegraded into lower molecular weight compounds. The 16S rRNA microbial community analysis indicated that at phylum level, both inoculum and dye acclimated cultures were mainly consisting of Proteobacteria which was 27.9, 53.6 and 68.9% in inoculum, suspension and anodic biofilm, respectively. At genus level, both suspension and biofilm contained decolorization as well as electrochemically active bacteria. The outcomes exhibited that the AB29 decolorization would contest with electrogenic bacteria for electrons.


Assuntos
Fontes de Energia Bioelétrica , Compostos Azo , Reatores Biológicos , Corantes , Eletrodos , Naftalenos , RNA Ribossômico 16S
12.
Sci Total Environ ; 776: 145934, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33647656

RESUMO

Microbial fuel cells (MFCs) that simultaneously remove organic contaminants and recovering metals provide a potential route for industry to adopt clean technologies. In this work, two goals were set: to study the feasibility of zinc removal from industrial effluents using MFCs and to understand the removal process by using reaction rate models. The removal of Zn2+ in MFC was over 96% for synthetic and industrial samples with initial Zn2+ concentrations less than 2.0 mM after 22 h of operation. However, only 83 and 42% of the zinc recovered from synthetic and industrial samples, respectively, was attached on the cathode surface of the MFCs. The results marked the domination of electroprecipitation rather than the electrodeposition process in the industrial samples. Energy dispersive X-ray (EDX) analysis showed that the recovered compound contained not only Zn but also O, evidence that Zn(OH)2 could be formed. The removal of Zn2+ in the MFC followed a mechanism where oxygen was reduced to hydroxide before reacting with Zn2+. Nernst equations and rate law expressions were derived to understand the mechanism and used to estimate the Zn2+ concentration and removal efficiency. The zero-, first- and second-order rate equations successfully fitted the data, predicted the final Zn2+ removal efficiency, and suggested that possible mechanistic reactions occurred in the electrolysis cell (direct reduction), MFC (O2 reduction), and control (chemisorption) modes. The half-life, t1/2, of the Zn2+ removal reaction using synthetic and industrial samples was estimated to be 7.0 and 2.7 h, respectively. The t1/2 values of the controls (without the power input from the MFC bioanode) were much slower and were recorded as 21.5 and 7.3 h for synthetic and industrial samples, respectively. The study suggests that MFCs can act as a sustainable and environmentally friendly technology for heavy metal removal without electrical energy input or the addition of chemicals.


Assuntos
Fontes de Energia Bioelétrica , Metais Pesados , Eletricidade , Eletrodos , Águas Residuárias , Zinco
13.
Appl Microbiol Biotechnol ; 85(5): 1373-81, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19697021

RESUMO

The effect of electron shuttles on electron transfer to microbial fuel cell (MFC) anodes was studied in systems where direct contact with the anode was precluded. MFCs were inoculated with Shewanella cells, and flavins used as the electron shuttling compound. In MFCs with no added electron shuttles, flavin concentrations monitored in the MFCs' bulk liquid increased continuously with FMN as the predominant flavin. The maximum concentrations were 0.6 microM for flavin mononucleotide and 0.2 microM for riboflavin. In MFCs with added flavins, micro-molar concentrations were shown to increase current and power output. The peak current was at least four times higher in MFCs with high concentrations of flavins (4.5-5.5 microM) than in MFCs with low concentrations (0.2-0.6 microM). Although high power outputs (around 150 mW/m(2)) were achieved in MFCs with high concentrations of flavins, a Clostridium-like bacterium along with other reactor limitations affected overall coulombic efficiencies (CE) obtained, achieving a maximum CE of 13%. Electron shuttle compounds (flavins) permitted bacteria to utilise a remote electron acceptor (anode) that was not accessible to the cells allowing current production until the electron donor (lactate) was consumed.


Assuntos
Fontes de Energia Bioelétrica , Elétrons , Flavinas/metabolismo , Shewanella/metabolismo , Anaerobiose , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Biodegradação Ambiental , Eletricidade , Eletroquímica , Eletrodos , Transporte de Elétrons , Fermentação , Mononucleotídeo de Flavina/metabolismo , Ácido Láctico/metabolismo , Oxirredução , Oxigênio , Riboflavina/metabolismo , Shewanella/crescimento & desenvolvimento
14.
Appl Microbiol Biotechnol ; 87(5): 1699-713, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20473665

RESUMO

The influence of various carbon anodes; graphite, sponge, paper, cloth, felt, fiber, foam and reticulated vitreous carbon (RVC); on microbial fuel cell (MFC) performance is reported. The feed was brewery wastewater diluted in domestic wastewater. Biofilms were grown at open circuit or under an external load. Microbial diversity was analysed as a function of current and anode material. The bacterial community formed at open circuit was influenced by the anode material. However at closed circuit its role in determining the bacterial consortia formed was less important than the passage of current. The rate and extent of organic matter removal were similar for all materials: over 95% under closed circuit. The biofilm in MFCs working at open circuit and in the control reactors, increased COD removal by up to a factor of nine compared with that for baseline reactors. The average voltage output was 0.6 V at closed circuit, with an external resistor of 300 kOmega and 0.75 V at open circuit for all materials except RVC. The poor performance of this material might be related to the surface area available and concentration polarizations caused by the morphology of the material and the structure of the biofilm. Peak power varied from 1.3 mW m(-2) for RVC to 568 mW m(-2) for graphite with biofilm grown at closed circuit.


Assuntos
Biodiversidade , Fontes de Energia Bioelétrica/microbiologia , Biofilmes/crescimento & desenvolvimento , Eletricidade , Eletrodos/microbiologia , Resíduos Industriais , Compostos Orgânicos/metabolismo , Microbiologia da Água
15.
Biofouling ; 26(1): 57-71, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20390557

RESUMO

The concept of an electro-active biofilm (EAB) has recently emerged from a few studies that discovered that certain bacteria which form biofilms on conductive materials can achieve a direct electrochemical connection with the electrode surface using it as electron exchanger, without the aid of mediators. This electro-catalytic property of biofilms has been clearly related to the presence of some specific strains that are able to exchange electrons with solid substrata (eg Geobacter sulfurreducens and Rhodoferax ferrireducens). EABs can be obtained principally from natural sites such as soils or seawater and freshwater sediments or from samples collected from a wide range of different microbially rich environments (sewage sludge, activated sludge, or industrial and domestic effluents). The capability of some microorganisms to connect their metabolisms directly in an external electrical power supply is very exciting and extensive research is in progress on exploring the possibilities of EABs applications. Indeed, the best known application is probably the microbial fuel cell technology that is capable of turning biomass into electrical energy. Nevertheless, EABs coated onto electrodes have recently become popular in other fields like bioremediation, biosynthesis processes, biosensor design, and biohydrogen production.


Assuntos
Biofilmes/crescimento & desenvolvimento , Eletrodos/microbiologia , Fontes de Energia Bioelétrica/microbiologia , Burkholderia/crescimento & desenvolvimento , Burkholderia/fisiologia , Eletroquímica , Transporte de Elétrons , Geobacter/crescimento & desenvolvimento , Geobacter/fisiologia , Esgotos/microbiologia , Propriedades de Superfície , Purificação da Água/métodos
16.
ACS Appl Mater Interfaces ; 12(33): 37079-37091, 2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32692534

RESUMO

Significant reductions in total cost of ownership can be realized by engineering PEM fuel cells to run on low-purity hydrogen. One of the main drawbacks of low-purity hydrogen fuels is the carbon monoxide fraction, which poisons platinum electrocatalysts and reduces the power output below useful levels. Platinum-tungsten oxide catalyst systems have previously shown high levels of CO tolerance during both ex situ and in situ investigations. In this work, we explore the mechanism of enhanced tolerance using in situ electrochemical attenuated total reflection-infrared (ATR-IR) and Raman spectroscopy methods and investigate, using a mixture of Pt/C and WO3 powders, the role of the WV/WVI redox couple in the oxidation of adsorbed CO.

17.
Front Psychol ; 11: 537612, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33424670

RESUMO

The misleading and propagandistic tendencies in American news reporting have been a part of public discussion from its earliest days as a republic (Innis, 2007; Sheppard, 2007). "Fake news" is hardly new (McKernon, 1925), and the term has been applied to a variety of distinct phenomenon ranging from satire to news, which one may find disagreeable (Jankowski, 2018; Tandoc et al., 2018). However, this problem has become increasingly acute in recent years with the Macquarie Dictionary declaring "fake news" the word of the year in 2016 (Lavoipierre, 2017). The international recognition of fake news as a problem (Pomerantsev and Weiss, 2014; Applebaum and Lucas, 2016) has led to a number of initiatives to mitigate perceived causes, with varying levels of success (Flanagin and Metzger, 2014; Horne and Adali, 2017; Sample et al., 2018). The inability to create a holistic solution continues to stymie researchers and vested parties. A significant contributor to the problem is the interdisciplinary nature of digital deception. While technology enables the rapid and wide dissemination of digitally deceptive data, the design and consumption of data rely on a mixture of psychology, sociology, political science, economics, linguistics, marketing, and fine arts. The authors for this effort discuss deception's history, both old and new, from an interdisciplinary viewpoint and then proceed to discuss how various disciplines contribute to aiding in the detection and countering of fake news narratives. A discussion of various fake news types (printed, staged events, altered photographs, and deep fakes) ensues with the various technologies being used to identify these; the shortcomings of those technologies and finally the insights offered by the other disciplines can be incorporated to improve outcomes. A three-point evaluation model that focuses on contextual data evaluation, pattern spread, and archival analysis of both the author and publication archives is introduced. While the model put forth cannot determine fact from fiction, the ability to measure distance from fact across various domains provides a starting point for evaluating the veracity of a new story.

18.
Water Sci Technol ; 60(11): 2879-87, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19934509

RESUMO

This study reports an investigation of the effect of the anode surface area on the performance of a single chamber microbial fuel cell (SCMFC) based biosensor for measuring the organic content of wastewater. A packed bed of graphite granules was used as the anode. The surface area of the anode was changed by altering the granule bed thickness (0.3 cm and 1 cm). The anode surface area was found to play a role in the dynamic response of the system. For a granule bed thickness of 1 cm and with an external resistance of 500 Omega, the response time (defined as the time required to achieve 95% of the steady-state current) was reduced by approximately 65% in comparison to a SCMFC biosensor with a carbon cloth anode.


Assuntos
Compostos Orgânicos/análise , Eliminação de Resíduos Líquidos/métodos , Microbiologia da Água/normas , Cloreto de Amônio/análise , Técnicas Biossensoriais , Cloreto de Cálcio/análise , Cloretos/análise , Sulfato de Cobre/análise , Eletrodos , Desenho de Equipamento , Cloreto de Magnésio/análise , Compostos de Manganês/análise , Sulfatos/análise , Eliminação de Resíduos Líquidos/estatística & dados numéricos , Água/análise , Compostos de Zinco/análise
19.
J Dev Behav Pediatr ; 40(4): 275-284, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30921105

RESUMO

OBJECTIVE: In an effort to promote the health and developmental outcomes of children born into poverty, the Centers for Disease Control and Prevention (CDC) conceptualized and designed the Legacy for Children™ (Legacy) public health prevention model. This article examines the impact of Legacy on children's cognitive and language development (intelligence quotient [IQ], achievement, language skills, and early reading skills) using both standardized assessments and parent-reported indictors through third grade. METHODS: Data were collected from 2001 to 2014 from 541 mother-child dyads who were recruited into the 2 concurrent randomized controlled trials of Legacy in Miami and Los Angels. Cognitive and/or language outcomes of children were assessed annually from age 2 to 5 years as well as during a follow-up visit in the third grade. RESULTS: Children experiencing Legacy at the Los Angeles site had significantly higher IQ and achievement scores at 2 and 6 years postintervention, equivalent to approximately one-third of an SD (4 IQ points). IQ results persisted over time, and the difference between intervention and comparison groups on achievement scores widened. There were no significant differences in cognitive outcomes in the Miami sample. There were no significant differences in language outcomes for either site. CONCLUSION: Legacy shows evidence of effectiveness as an intervention to prevent cognitive delays among children living in poverty. The mixed findings across sites may not only reflect the impact of heterogeneous risk profiles noted by other intervention research programs but also warrant additional study.


Assuntos
Sucesso Acadêmico , Desenvolvimento Infantil , Deficiências do Desenvolvimento/prevenção & controle , Intervenção Educacional Precoce , Educação não Profissionalizante , Mães , Pobreza , Saúde Pública , Adolescente , Adulto , Criança , Desenvolvimento Infantil/fisiologia , Pré-Escolar , Intervenção Educacional Precoce/métodos , Educação não Profissionalizante/métodos , Feminino , Florida , Seguimentos , Humanos , Desenvolvimento da Linguagem , Los Angeles , Masculino , Mães/educação , Resultado do Tratamento , Adulto Jovem
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