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3.
Am J Emerg Med ; 48: 375.e5-375.e6, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33836933

RESUMO

Priapism is a severe urologic condition requiring emergency management. Ischemic priapism is the most common subtype which is characterized by a long-lasting, painful, and rigid erection which can be caused by medications with alpha-adrenergic properties such as hydroxyzine. Typically, medication-induced priapism is reported at therapeutic doses and few case reports exist implicating medication overdose as the cause. We report a case of a patient taking hypercompliant doses of hydroxyzine hydrochloride for worsening insomnia (200-600 mg), including the night before admission. Blood-gas analysis of blood from the right corpora was completed and revealed a pH of 6.736, pCO2 of 147, HCO3 of 18.6 and a base excess of 17.7. The patient required aspiration and 560 µg of intracavernosal phenylephrine to achieve sustained detumescence. Emergency physicians should be aware of this risk as priapism is a medical emergency and this is the first report with hydroxyzine after an intentional overdose to our knowledge.


Assuntos
Antagonistas dos Receptores Histamínicos H1/intoxicação , Hidroxizina/intoxicação , Priapismo/induzido quimicamente , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Adulto , Humanos , Masculino , Priapismo/terapia
4.
PeerJ ; 6: e6002, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30671285

RESUMO

Soil physical parameter calculation by inverse modelling provides an indirect way of estimating the unsaturated hydraulic properties of soils. However many measurements are needed to provide sufficient data to determine unknown parameters. The objective of this research was to assess the use of unsaturated water flow and solute transport experiments, in horizontal packed soil columns, to estimate the parameters that govern water flow and solute transport. The derived parameters are then used to predict water infiltration and solute migration in a repacked soil wedge. Horizontal columns packed with Red Ferrosol were used in a nitrate diffusion experiment to estimate either three or six parameters of the van Genuchten-Mualem equation while keeping residual and saturated water content, and saturated hydraulic conductivity fixed to independently measured values. These parameters were calculated using the inverse optimisation routines in Hydrus 1D. Nitrate concentrations measured along the horizontal soil columns were used to independently determine the Langmuir adsorption isotherm. The soil hydraulic properties described by the van Genuchten-Mualem equation, and the NO3 - adsorption isotherm, were then used to predict water and NO3 - distributions from a point-source in two 3D flow scenarios. The use of horizontal columns of repacked soil and inverse modelling to quantify the soil water retention curve was found to be a simple and effective method for determining soil hydraulic properties of Red Ferrosols. These generated parameters supported subsequent testing of interactive flow and reactive transport processes under dynamic flow conditions.

5.
Antonie Van Leeuwenhoek ; 112(4): 615-632, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30357592

RESUMO

This study determined the loading impacts of wood-based biochar on the eukaryotic community in three different soils (brown sandy loam-BSL, red loam-RL and a black clay loam-BCL) using a pot trial conducted over 10 months. Soil analysis and 18S rRNA gene sequencing performed using the Illumina MiSeq platform was carried out to evaluate the changes in eukaryotic community composition in relation to different added amounts of biochar. It was found that biochar addition had a negligible effect on diversity parameters in the brown sandy loam Kurosol (BSL) and red loam Dermosol (RL) soils. There were, however, significant changes in eukaryotic community composition of these biochar amended soils. These changes were most discernible in the lighter (low clay content) BSL soil for the fungal communities (F = 3.0106, p = 0.0003) present and also when total eukaryotes were considered (F = 2.3907, p = 0.0002). In this respect Glomeromycota seem to be slightly promoted in the lighter BSL soils, which might be due to increased soil porosity and soil chemical fertility. Clay rich BCL soil community structure correlated to a greater degree with soil chemistry influenced by biochar addition. The results showed that soil microeukaryotes were affected by short term carbon amendment, though to a limited extent. The limited effect of biochar loading rates on the soil microbiology could be due to the short incubation period, the lack of added fertiliser nutrients, and also the inherent stability of the soil eukaryotic community. The data suggested the impacts that were observed however included important plant symbiotic organisms. The results also imply biochar applications at different loading levels have differential effects on soil microeurokaryotes in relation to soil properties in particular clay content.


Assuntos
Carvão Vegetal/farmacologia , Eucariotos/efeitos dos fármacos , Fungos/efeitos dos fármacos , Solo/parasitologia , Carvão Vegetal/análise , Eucariotos/classificação , Eucariotos/genética , Eucariotos/isolamento & purificação , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Micobioma , Solo/química , Microbiologia do Solo
6.
Am J Emerg Med ; 36(10): 1922.e3-1922.e4, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30001816

RESUMO

Acute, unintentional drug-related poisonings lead to an estimated 418,313 ED visits in 2014, according to the latest statistics from the Center for Disease Control and Prevention. While most of these were opiate-related poisonings, anticoagulant rodenticides were the most common cause of rodenticide-related poisoning in the United States. Many clinical syndromes and treatment algorithms have been described for patients with anticoagulant rodenticide poisoning. We report a case of an acute ingestion of two anticoagulant rodenticides and successful reversal of coagulation parameters using 4-factor prothrombin complex concentrate in a fixed-dose approach.


Assuntos
4-Hidroxicumarinas/intoxicação , Anticoagulantes/efeitos adversos , Fatores de Coagulação Sanguínea/administração & dosagem , Hemorragia/induzido quimicamente , Drogas Ilícitas/intoxicação , Rodenticidas/intoxicação , Medicamentos Sintéticos/efeitos adversos , Vitamina K/administração & dosagem , Dor Abdominal/induzido quimicamente , Idoso , Transtornos da Coagulação Sanguínea/induzido quimicamente , Contaminação de Medicamentos , Cálculos da Dosagem de Medicamento , Hemorragia/tratamento farmacológico , Humanos , Masculino , Resultado do Tratamento
8.
AoB Plants ; 10(2): ply015, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29593855

RESUMO

There is high uncertainty in the contribution of land-use change to anthropogenic climate change, especially pertaining to below-ground carbon loss resulting from conversion of primary-to-secondary forest. Soil organic carbon (SOC) and coarse roots are concentrated close to tree trunks, a region usually unmeasured during soil carbon sampling. Soil carbon estimates and their variation with land-use change have not been correspondingly adjusted. Our aim was to deduce allometric equations that will allow improvement of SOC estimates and tree trunk carbon estimates, for primary forest stands that include large trees in rugged terrain. Terrestrial digital photography, photogrammetry and GIS software were used to produce 3D models of the buttresses, roots and humus mounds of large trees in primary forests dominated by Eucalyptus regnans in Tasmania. Models of 29, in situ eucalypts were made and analysed. 3D models of example eucalypt roots, logging debris, rainforest tree species, fallen trees, branches, root and trunk slices, and soil profiles were also derived. Measurements in 2D, from earlier work, of three buttress 'logs' were added to the data set. The 3D models had high spatial resolution. The modelling allowed checking and correction of field measurements. Tree anatomical detail was formulated, such as buttress shape, humus volume, root volume in the under-sampled zone and trunk hollow area. The allometric relationships developed link diameter at breast height and ground slope, to SOC and tree trunk carbon, the latter including a correction for senescence. These formulae can be applied to stand-level carbon accounting. The formulae allow the typically measured, inter-tree SOC to be corrected for not sampling near large trees. The 3D models developed are irreplaceable, being for increasingly rare, large trees, and they could be useful to other scientific endeavours.

9.
J Vis Exp ; (110): e53819, 2016 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-27166738

RESUMO

Initial evaluations of large microbial libraries for potential producers of novel antimicrobial proteins require both qualitative and quantitative methods to screen for target enzymes prior to investing greater research effort and resources. The goal of this protocol is to demonstrate two complementary assays for conducting these initial evaluations. The microslide diffusion assay provides an initial or simple detection screen to enable the qualitative and rapid assessment of proteolytic activity against an array of both viable and heat-killed bacterial target substrates. As a counterpart, the increased sensitivity and reproducibility of the dye-release assay provides a quantitative platform for evaluating and comparing environmental influences affecting the hydrolytic activity of protein antimicrobials. The ability to label specific heat-killed cell culture substrates with Remazol brilliant blue R dye expands this capability to tailor the dye-release assay to characterize enzymatic activity of interest.


Assuntos
Antraquinonas/química , Anti-Infecciosos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Salmonella enterica/efeitos dos fármacos , Bacillus subtilis/metabolismo , Proteínas de Bactérias/metabolismo , Bioensaio , Peptidoglicano/metabolismo , Reprodutibilidade dos Testes , Salmonella enterica/metabolismo
10.
Bioconjug Chem ; 27(5): 1276-84, 2016 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-27098672

RESUMO

A disulfide-bridged peptide drug development candidate contained two oligopeptide chains with 11 and 12 natural amino acids joined by a disulfide bond at the N-terminal end. An efficient biotechnology based process for the production of the disulfide-bridged peptide was developed. Initially, the two individual oligopeptide chains were prepared separately by designing different fusion proteins and expressing them in recombinant E. coli. Enzymatic or chemical cleavage of the two fusion proteins provided the two individual oligopeptide chains which could be conjugated via disulfide bond by conventional chemical reaction to the disulfide-bridged peptide. A novel heterodimeric system to bring the two oligopeptide chains closer and induce disulfide bond formation was designed by taking advantage of the self-assembly of a leucine zipper system. The heterodimeric approach involved designing fusion proteins with the acidic and basic components of the leucine zipper, additional amino acids to optimize interaction between the individual chains, specific cleavage sites, specific tag to ensure separation, and two individual oligopeptide chains. Computer modeling was used to identify the nature and number of amino acid residue to be inserted between the leucine zipper and oligopeptides for optimum interaction. Cloning and expression in rec E. coli, fermentation, followed by cell disruption resulted in the formation of heterodimeric protein with the interchain disulfide bond. Separation of the desired heterodimeric protein, followed by specific cleavage at methionine by cyanogen bromide provided the disulfide-bridged peptide.


Assuntos
Biotecnologia , Dissulfetos/química , Peptídeos/química , Peptídeos/metabolismo , Sequência de Aminoácidos , Escherichia coli/genética , Modelos Moleculares , Peptídeos/genética , Multimerização Proteica , Estrutura Quaternária de Proteína
11.
J Clin Gastroenterol ; 50(1): 45-51, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26125461

RESUMO

GOALS: To objectively assess when gastroenterology (GI) fellows achieve technical competency to perform colonoscopy independently. BACKGROUND: New guidelines to assess the procedural competency of GI fellows in training have been developed. Although comprehensive, they do not account for the quality metrics to which independently practicing gastroenterologists are held. STUDY: We performed a prospective study examining consecutive colonoscopies performed by GI fellows from November 2013 through March 2014 at an academic medical center. Using a brief postprocedure questionnaire and the online medical record, we measured rates of independent fellow cecal intubation rate (CIR), insertion time to the cecum (cecal IT), and independent polypectomy rate. Our secondary outcomes were adenoma detection rate and polyp detection rate. RESULTS: A total of 898 colonoscopies performed by 10 GI fellows were analyzed. In the multivariate analysis, CIR [odds ratio (OR)=1.29, P=0.012], cecal IT (ß-coefficient=0.19, P=0.006), and rates of unassisted independent snare polypectomy (OR=1.36, P<0.001) all improved significantly with increased number of procedures performed (OR and ß-coefficient per 100 colonoscopies performed). After performing 500 colonoscopies, fellows achieved a mean CIR>90%, cecal IT between 7 and 10 minutes, and independent polypectomy rate of 90% with further improvement in cecal IT to <7 minutes, and independent snare polypectomy of >95% after 700 cases. CONCLUSIONS: Current procedural recommendations for fellowship training may underestimate the technical skill necessary for independent GI practice upon completion of fellowship. Technical proficiency in snare polypectomy may lag behind proficiency in cecal intubation.


Assuntos
Competência Clínica , Colonoscopia/normas , Neoplasias Colorretais/diagnóstico , Gastroenterologia/normas , Centros Médicos Acadêmicos , Adenoma/diagnóstico , Adenoma/patologia , Adulto , Idoso , Pólipos do Colo/cirurgia , Colonoscopia/educação , Neoplasias Colorretais/patologia , Bolsas de Estudo , Feminino , Gastroenterologia/educação , Guias como Assunto , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos Prospectivos , Fatores de Tempo
12.
R I Med J (2013) ; 98(5): 15-8, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25938399

RESUMO

Chronic hepatitis B (HBV) in the Asian and Pacific Islander (API) American population is an under-recognized health issue in the United States. Among foreign-born API, the prevalence of HBV is approximately 10%. The prevalence in the general population is below 0.5%; among non-Hispanic whites it is below 0.2%. We examined beliefs held by the API populations in Rhode Island (RI) about personal HBV status and compared them with their actual HBV status. Of 59 total study participants, only 19 (32%) participants correctly knew their HBV status. Six (10%) participants were carriers of HBV; 18 (31%) lacked immunity to the virus. This pilot study suggests the RI API population is not knowledgeable about their own HBV status and are inadequately screened, vaccinated against, and treated for HBV. Increased statewide screening and education efforts, tailored to address this population, are needed to identify and inform those in need of medical attention or vaccination.


Assuntos
Asiático , Vacinas contra Hepatite B/administração & dosagem , Hepatite B Crônica/etnologia , Programas de Imunização , Havaiano Nativo ou Outro Ilhéu do Pacífico , Adulto , Estudos Transversais , Feminino , Hepatite B Crônica/prevenção & controle , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Prevalência , Rhode Island/epidemiologia
13.
Phys Chem Chem Phys ; 15(33): 13737-83, 2013 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-23652494

RESUMO

This paper presents a review of the redox and electrocatalytic properties of transition metal oxide electrodes, paying particular attention to the oxygen evolution reaction. Metal oxide materials may be prepared using a variety of methods, resulting in a diverse range of redox and electrocatalytic properties. Here we describe the most common synthetic routes and the important factors relevant to their preparation. The redox and electrocatalytic properties of the resulting oxide layers are ascribed to the presence of extended networks of hydrated surface bound oxymetal complexes termed surfaquo groups. This interpretation presents a possible unifying concept in water oxidation catalysis - bridging the fields of heterogeneous electrocatalysis and homogeneous molecular catalysis.

14.
Med Teach ; 35(3): 226-30, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23425119

RESUMO

BACKGROUND: The incorporation of technology into medical education is critical for learners. Little is known about the effect of integrating iPad technology into undergraduate medical education. AIMS: We introduced iPads into the first-year curriculum in 2011-2012. We aimed to evaluate students' use of, and attitudes toward, the iPad. METHODS: We administered two surveys to students during the 2011-2012 academic year. Additionally, we conducted focus groups to further evaluate the effectiveness of iPad integration into the curriculum. RESULTS: Survey data reflect mixed attitudes toward the use of the iPad in the preclinical curriculum. While a vast majority of students agree "the iPad has value in the medical curriculum" (79% in the first survey; 65% in the second survey), there was a decrease over time in the view that "the iPad is a positive addition to the curriculum" (75% in the first survey; 49% in the second survey). Focus group data indicate students appreciate certain aspects of iPad use in the curriculum, including improved curriculum interactivity, but the majority believe it cannot replace printed handouts at this time. DISCUSSION: The iPad provides some benefits in undergraduate medical education. More studies are necessary to determine how the iPad is best incorporated into medical education.


Assuntos
Currículo , Educação de Graduação em Medicina , Minicomputadores , Feminino , Grupos Focais , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Projetos Piloto , Rhode Island , Estudantes de Medicina/psicologia , Inquéritos e Questionários
15.
Phys Chem Chem Phys ; 15(14): 5224-37, 2013 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-23348122

RESUMO

The oxygen evolution reaction at multi-cycled iron oxy-hydroxide films in aqueous alkaline solution is discussed. Steady-state Tafel plot analysis and electrochemical impedance spectroscopy have been used to elucidate the kinetics and mechanism of oxygen evolution. Tafel slopes of ca. 60 mV dec(-1) and 40 mV dec(-1) are found at low overpotentials depending on the oxide growth conditions, with an apparent Tafel slope of ca. 120 mV dec(-1) at high overpotentials. Reaction orders of ca. 0.5 and 1.0 are observed at low and high overpotentials, again depending on the oxide growth conditions. A mechanistic scheme involving the active participation of octahedrally coordinated anionic iron oxyhydroxide surfaquo complexes, which form the porous hydrous layer, is proposed. The latter structure contains considerable quantities of water molecules which facilitate hydroxide ion discharge at the metal site during active oxygen evolution. This work brings together current research in heterogeneous electrocatalysis and homogeneous molecular catalysis for water oxidation.


Assuntos
Técnicas Eletroquímicas , Compostos Férricos/química , Oxigênio/química , Catálise , Espectroscopia Dielétrica , Oxirredução , Água/química
16.
J Contam Hydrol ; 144(1): 66-77, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23159761

RESUMO

Preferential flow in agricultural soils has been demonstrated to result in agrochemical mobilisation to shallow ground water. Land managers and environmental regulators need simple cost effective techniques for identifying soil - land use combinations in which preferential flow occurs. Existing techniques for identifying preferential flow have a range of limitations including; often being destructive, non in situ, small sampling volumes, or are subject to artificial boundary conditions. This study demonstrated that high frequency soil moisture monitoring using a multi-sensory capacitance probe mounted within a vertically rammed access tube, was able to determine the occurrence, depth, and wetting front velocity of preferential flow events following rainfall. Occurrence of preferential flow was not related to either rainfall intensity or rainfall amount, rather preferential flow occurred when antecedent soil moisture content was below 226 mm soil moisture storage (0-70 cm). Results indicate that high temporal frequency soil moisture monitoring may be used to identify soil type - land use combinations in which the presence of preferential flow increases the risk of shallow groundwater contamination by rapid transport of agrochemicals through the soil profile. However use of high frequency based soil moisture monitoring to determine agrochemical mobilisation risk may be limited by, inability to determine the volume of preferential flow, difficulty observing macropore flow at high antecedent soil moisture content, and creation of artificial voids during installation of access tubes in stony soils.


Assuntos
Monitoramento Ambiental/métodos , Água Subterrânea , Solo , Desenho de Equipamento , Chuva , Tasmânia
17.
J Pediatr Genet ; 2(1): 25-31, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27625836

RESUMO

Array comparative genomic hybridization (aCGH) testing can diagnose chromosomal microdeletions and duplications too small to be detected by conventional cytogenetic techniques. We need to consider which patients are more likely to receive a diagnosis from aCGH testing versus patients that have lower likelihood and may benefit from broader genome wide scanning. We retrospectively reviewed charts of a population of 200 patients, 117 boys and 83 girls, who underwent aCGH testing in Genetics Clinic at Rhode Island hospital between 1 January/2008 and 31 December 2010. Data collected included sex, age at initial clinical presentation, aCGH result, history of seizures, autism, dysmorphic features, global developmental delay/intellectual disability, hypotonia and failure to thrive. aCGH analysis revealed abnormal results in 34 (17%) and variants of unknown significance in 24 (12%). Patients with three or more clinical diagnoses had a 25.0% incidence of abnormal aCGH findings, while patients with two or fewer clinical diagnoses had a 12.5% incidence of abnormal aCGH findings. Currently, we provide families with a range of 10-30% of a diagnosis with aCGH testing. With increased clinical complexity, patients have an increased probability of having an abnormal aCGH result. With this, we can provide individualized risk estimates for each patient.

18.
Methods Mol Biol ; 913: 415-25, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22895776

RESUMO

Soil salinity is a form of land degradation in which salts accumulate in the soil profile to an extent that plant growth or infrastructure are negatively affected. A range of both field and laboratory procedures exist for measuring soil salinity. In the field, soil salinity is usually inferred from apparent electrical conductivity (EC(a)) using a range of devices, depending on the required depth of analysis, or size of the survey area. Field measurements of EC(a) require calibration to the actual salt content by laboratory analysis. In the laboratory, soil salinity is usually assessed by determining either the total soluble salts by evaporation of a soil water extract (TSS), or by determining the electrical conductivity (EC) of either a 1:5 distilled water:soil dilution, or a saturated paste extract. Although procedures for measuring soil salinity appear relatively straightforward, differences in methodology have considerable influence on measured values and interpretation of results.


Assuntos
Monitoramento Ambiental/métodos , Salinidade , Solo/química
19.
Fam Pract ; 29(5): 601-8, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22379185

RESUMO

PURPOSE: We compared physicians' self-reported attitudes and behaviours regarding electronic health record (EHR) use before and after installation of computers in patient examination rooms and transition to full implementation of an EHR in a family medicine training practice to identify anticipated and observed effects these changes would have on physicians' practices and clinical encounters. METHODS: We conducted two individual qualitative interviews with family physicians. The first interview was before and second interview was 8 months later after full implementation of an EHR and computer installation in the examination rooms. Data were analysed through project team discussions and subsequent coding with qualitative analysis software. RESULTS: At the first interviews, physicians frequently expressed concerns about the potential negative effect of the EHR on quality of care and physician-patient interaction, adequacy of their skills in EHR use and privacy and confidentiality concerns. Nevertheless, most physicians also anticipated multiple benefits, including improved accessibility of patient data and online health information. In the second interviews, physicians reported that their concerns did not persist. Many anticipated benefits were realized, appearing to facilitate collaborative physician-patient relationships. Physicians reported a greater teaching role with patients and sharing online medical information and treatment plan decisions. CONCLUSIONS: Before computer installation and full EHR implementation, physicians expressed concerns about the impact of computer use on patient care. After installation and implementation, however, many concerns were mitigated. Using computers in the examination rooms to document and access patients' records along with online medical information and decision-making tools appears to contribute to improved physician-patient communication and collaboration.


Assuntos
Atitude do Pessoal de Saúde , Atitude Frente aos Computadores , Registros Eletrônicos de Saúde , Exame Físico , Consultórios Médicos , Medicina de Família e Comunidade , Humanos , Relações Médico-Paciente , Pesquisa Qualitativa , Qualidade da Assistência à Saúde , Estados Unidos
20.
Phys Chem Chem Phys ; 13(48): 21530-51, 2011 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-22068318

RESUMO

Outstanding issues regarding the film formation, redox switching characteristics and the oxygen evolution reaction (OER) electrocatalytic behaviour of multicycled iron oxyhydroxide films in aqueous alkaline solution have been revisited. The oxide is grown using a repetitive potential multicycling technique, and the mechanism of the latter hydrous oxide formation process has been discussed. A duplex layer model of the oxide/solution interphase region is proposed. The acid/base behaviour of the hydrous oxide and the microdispersed nature of the latter material has been emphasised. The hydrous oxide is considered as a porous assembly of interlinked octahedrally coordinated anionic metal oxyhydroxide surfaquo complexes which form an open network structure. The latter contains considerable quantities of water molecules which facilitate hydroxide ion discharge at the metal site during active oxygen evolution, and also charge compensating cations. The dynamics of redox switching has been quantified via analysis of the cyclic voltammetry response as a function of potential sweep rate using the Laviron-Aoki electron hopping diffusion model by analogy with redox polymer modified electrodes. Steady state Tafel plot analysis has been used to elucidate the kinetics and mechanism of oxygen evolution. Tafel slope values of ca. 60 mV dec(-1) and ca. 120 mV dec(-1) are found at low and high overpotentials respectively, whereas the reaction order with respect to hydroxide ion activity changes from ca. 3/2 to ca. 1 as the potential is increased. These observations are rationalised in terms of a kinetic scheme involving Temkin adsorption and the rate determining formation of a physisorbed hydrogen peroxide intermediate on the oxide surface. The dual Tafel slope behaviour is ascribed to the potential dependence of the surface coverage of adsorbed intermediates.

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