899 resultados para Lead, Jane (Ward), 1623-1704


Relevância:

20.00% 20.00%

Publicador:

Resumo:

We report on the fabrication of novel lead-germanate glasses and fibers. We have characterized these glasses in terms of their thermal properties, Raman spectra and refractive indices (both linear and nonlinear) and present them as viable alternatives to tellurite glasses for applications requiring highly nonlinear optical fibers. © 2013 Optical Society of America.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The development of an electroanalytical method for simultaneous determination of copper and lead ions in sugar cane spirit (cachaça) using carbon paste electrode modified with ascorbic acid and carbon nanotubes (CPE-AaCNT) is described. Squarewave voltammetry (SWV) with anodic stripping was employed, and this technique was optimized with respect to the following parameters: frequency (50 Hz), amplitude (100 mV) and scan increment (9 mV). The analytical curves were linear in the range from 0.0900 to 7.00 mg L - 1 for lead and copper. The limits of detection were 48.5 and 23.9 µg L - 1 for lead and copper, respectively. The developed method was applied to the simultaneous determination of copper and lead in five commercial samples of sugar cane spirit. The results were in good agreement with those obtained by F AAS/GF AAS (flame atomic absorption spectrometry/graphite furnace atomic absorption spectrometry) and showed that CPE-AaCNT can be successfully employed in the simultaneous determination of these metals in real sugar cane spirit samples.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

ABSTRACT: Analytical procedures for U-Pb isotope dilution analyses at the Pará-Iso isotope geology laboratory of the Federal University of Pará (UFPA) are described in detail. The procedures are applied to zircon, titanite, rutile, apatite, columbite-tantalite and whole rock. Reagent preparation and chemical processing are done in clean-room conditions. Samples are dissolved using Teflon™ microcapsules in steel jacket Teflon™ Parr Instrument™ bomb or Teflon™ screw cap containers. U and Pb are separated using anion exchange AG 1x8 resin columns. Typical blanks for mineral sample amounts of 0.01 to 1.0 mg are less than 1 pg U and 20-30 pg Pb. Isotope analysis of the U and Pb from the same filament are carried out using a Finnigan MAT 262 mass-spectrometer in static and dynamic modes. The current analytical level is demonstrated on analyses of international standard zircon 91500 with three different 235U-205Pb and 235U-208Pb isotope tracers and whole rock standards. Results of analyses of two zircon samples are also presented.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A queimadura corresponde ao quadro resultante da ação direta ou indireta do calor do fogo, de substâncias químicas ou da eletricidade sobre o organismo humano. Alguns estudos apontam as crianças como as maiores vítimas. Procedimentos inerentes ao processo de recuperação são reconhecidos como particularmente dolorosos. A frequência de procedimentos médicos invasivos, situação constante ao paciente vítima de queimadura, favorece a emissão de comportamentos concorrentes pela criança, bem como pode ocasionar a generalização do caráter aversivo do procedimento invasivo para estímulos presentes no ambiente, justificando estudos sobre a eficácia de intervenções neste contexto. A pesquisa foi dividida em dois estudos com objetivos específicos. Estudo 1 (n=5): caracterizar comportamentos de crianças vítimas de queimadura emitidos durante procedimento de curativo sem sedação em enfermaria e comparar a frequência de comportamentos concorrentes e não concorrentes emitidos por estas crianças em duas sessões consecutivas deste procedimento. Estudo 2 (n=2): analisar os efeitos do uso de instrução sobre a frequência de comportamentos concorrentes e não concorrentes em crianças vítimas de queimadura durante procedimento de curativo sem sedação em enfermaria. Participaram sete crianças (4 meninos e 3 meninas; 7 a 12 anos) vítimas de queimadura em área corporal inferior a 70% e seus acompanhantes, selecionados em um Centro de Tratamento de Queimados (CTQ). Como instrumentos, foram utilizados: (a) Protocolo de consulta à equipe de saúde; (b) Lista de Verificação Comportamental para crianças/adolescentes (CBCL 6-18anos); (c) Roteiro de entrevista com a criança; (d) Escala de observação comportamental OSBD (Observation Scale of Behavioral Distress); (e) Escala facial para avaliar a percepção de dor da criança (FACES); e (f) Manual de instrução sobre o procedimento de curativo. No Estudo 1, observou-se maior frequência de comportamentos concorrentes sobre os não concorrentes nas duas sessões de curativo. No Estudo 2, após o uso do Manual de instrução, observou-se redução estatisticamente significante na frequência do comportamento concorrente Choramingar (= 0,0447) e aumento significativo (= 0,0324) na frequência do comportamento não concorrente Auxiliar na execução do procedimento. Houve correlação significativa (p-valor = 0,0066) entre a frequência de comportamentos não concorrentes entre as crianças do Estudo 1 e as que participaram do Estudo 2, sugerindo que a intervenção, por meio de instruções, foi eficaz para aumentar a frequência de comportamentos não concorrentes nas crianças participantes do Estudo 2.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

O presente estudo descreve a ocorrência de intoxicação por chumbo em bovinos e galinhas no Pará, Brasil. Em um lote composto de 80 bezerros de um rebanho leiteiro, 10 animais ficaram doentes e nove morreram, e um animal se recuperou após ser removido do piquete. Após a inspeção deste piquete, foi observada a presença de baterias de caminhões usados para armazenar a energia captada por painéis solares. Os sinais clínicos observados nos bezerros incluíam dificuldade respiratória, corrimento nasal, salivação excessiva, opacidade da córnea, pressão da cabeça contra objetos e decúbito. As galinhas tinham diminuída oviposição e os ovos produzidos eram com cascas malformadas ou tinham a casca mais fina. Os achados de necropsia e as alterações histopatológicas observadas nos bovinos eram de pouco significado, com exceção de um animal que mostrou leve astrocitose no córtex cerebral. Em uma das galinhas, na histopatologia renal observou-se leve necrose tubular aguda multifocal. As concentrações de chumbo médios nos fígados e rins dos bovinos eram 93,91mg/kg e 209,76mg/kg, respectivamente, e a concentração média no fígado de galinhas foi 105,02mg/ kg. Concluiu-se que a fonte de contaminação por chumbo nesses bezerros e galinhas eram placas de bateria de caminhão, aos quais os animais tiveram acesso na pastagem.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVES: Drug safety problems can lead to hospital admission. In Brazil, the prevalence of hospitalization due to adverse drug events is unknown. This study aims to estimate the prevalence of hospitalization due to adverse drug events and to identify the drugs, the adverse drug events, and the risk factors associated with hospital admissions. METHOD: A cross-sectional study was performed in the internal medicine ward of a teaching hospital in São Paulo State, Brazil, from August to December 2008. All patients aged ≥18 years with a length of stay ≥24 hours were interviewed about the drugs used prior to hospital admission and their symptoms/complaints/causes of hospitalization. RESULTS: In total, 248 patients were considered eligible. The prevalence of hospitalization due to potential adverse drug events in the ward was 46.4%. Overprescribed drugs and those indicated for prophylactic treatments were frequently associated with possible adverse drug events. Frequently reported symptoms were breathlessness (15.2%), fatigue (12.3%), and chest pain (9.0%). Polypharmacy was a risk factor for the occurrence of possible adverse drug events. CONCLUSION: Possible adverse drug events led to hospitalization in a high-complexity hospital, mainly in polymedicated patients. The clinical outcomes of adverse drug events are nonspecific, which delays treatment, hinders causality analysis, and contributes to the underreporting of cases.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Human health and environmental concerns are not usually considered at the same time. Tin-lead solders are still widely used in several countries, including Brazil, by manufacturers of electronic assemblies. One of the options to reduce or eliminate lead from the manufacturing environment is its replacement with lead-free alloys. This paper applies emergy synthesis and the DALY indicator (Disability Adjusted Life Years) to assess the impact of manufacturing soft solder using tin, lead and other metals on the environment and on human health. The results are presented together with the company's financial results and the results calculated from the Brazilian statistical value of life. The calculation of emergy per unit showed that more resources are used to produce one ton of lead-free solders than to produce one ton of tin-lead solders, with and without the use of consumer waste recovered through a reverse logistics system. The assessment of air emissions during solder production shows that the benefits of the lead-free solution are limited to the stages of manufacturing and assembling. The tin-lead solder appears as the best option in terms of resource use efficiency and with respect to emissions into the atmosphere when the mining stage is included. A discussion on the influence of the system's boundaries on the decision-making process for materials substitution is presented. (C) 2012 Elsevier Ltd. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Agricultural use of tannery sludge (TS) may increase risks to soils. Thus, composting is recognized as one of the most suitable alternatives for TS recycling. Field experiments were carried out to evaluate the effects of composted tannery sludge (CTS) on chromium (Cr), cadmium (Cd), nickel (Ni), and lead (Pb) accumulation in soil after 3 years. Soil samples were collected 60 days after CTS application. After 3 years, The CTS increased Cr and Ni content, while Cd and Pb contents decreased. The third year, Cr contents showed linear increases as CTS rates were applied. The application of CTS, after 3 years, in the 2.5, 5, and 10 Mg ha(-1) increased Cr significantly (140.7%, 159.7%, and 19%, respectively) and Ni (32%, 53%, and 43.8%, respectively) contents in the soil surface layer. This means that consecutive amendments of CTS increase Cr contents in the soil and plants.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The processing of ferroelectric BaBi4Ti4O15 (BBT) ceramics from powders prepared by conventional solid state reaction (SSR) and mechanochemical activation (MA) has been investigated. It was shown that MA synthesis reduces the synthesis temperature of BBT powders, leading to smaller particles with reduced anisotropy and consequently to smaller grain size of ceramics. Dielectric properties were investigated in a wide range of temperatures (20-800 degrees C) and frequencies (1.21 kHz to 1 MHz). The relative dielectric permittivity at Curie temperature was higher for solid state obtained ceramics than for the mechanically treated ones. The conductivity of sintered samples was studied, suggesting decreasing of conductivity of BBT-MA in comparison with BBT-SS ceramics. The influence of the grain and the grain boundaries contribution to the dielectric behavior in both ceramics was analyzed through impedance spectroscopy. A well-defined ferroelectric hysteresis loop was obtained for both samples. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The constant search for improvement and survival of the companies makes essential the utilization of cost reduction strategies and resources optimization. This study had as its objective the utilization of Lean Manufacturing tools for the repair process lead time reduction, in a car audio manufacturer. Performing an action research, the major problems were studied, such as the potential causes and the possible improvement activities, using the DMAIC methodology. An action plan was developed for all involved processes and, as a result, the objective was reached by making a direct impact on the customers’ satisfaction and adding a competitive differential for the company