Natural dyeing of cotton is commonly associated with the use of metallic mordants, which are related to harmful effects on the environment and human health. For this reason, more environmentally sustainable processes should be investigated. In this work, cotton was cationized with ovalbumin by cross-linking in order to improve its dyeing with natural cochineal dye. Different pretreatments with chitosan, synthetic cationizer, and metal mordants were also carried out at different dyeing pH values. The best dyeing results were obtained at pH 3 at 55℃ on fiber pretreated by padding with a liquor concentration of 150 g L−1 ovalbumin and 90 g L−1 cross-linker. This cationization of ovalbumin by cross-linking was confirmed by Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, changes in the isoelectric point of the fabrics, and scanning electron microscopy. The kinetic study showed that the pseudo second-order model best represented the experimental data, indicating that the dyeing can be controlled by the chemisorption process. The equilibrium data were easily adjusted by the Langmuir model, indicating the formation of a dye monolayer in the cationized cotton. The thermodynamic study indicated that dye adsorption was spontaneous and exothermic. The cationized fabric with ovalbumin presented low wash fastness, good light fastness, and increase in tensile strength and crease recovery, with a decrease of hydrophilicity when compared with other treatments. Thus, ovalbumin is a viable and eco-friendly alternative in the dyeing of cotton with cochineal.
Silk fabric was dyed with extract of roasted yerba mate ( Ilex paraguariensis). Dyeing experiments were carried out at varying dyestuff concentration, temperature and pH. The influence of mordants, such as potassium alum and tannin, was investigated. The best results in dyeing were produced with 20 g L–1 of dyestuff concentration, pH 3 and temperature of 90℃. Mordants showed negligible influence. The kinetic study showed that the pseudo-second-order equation better represented experimental data, which is related to the chemisorption process as the rate-controlling step. The equilibrium data were easily adjusted by the Langmuir–Freundlich model, indicating the significant contribution of the chemisorption process in a monolayer followed by a multilayer physisorption. The thermodynamic study indicated that dye adsorption was spontaneous and endothermic.
Apoio: sub-projeto de estudo financiado pelo CNPq (processo nº 409315/2006-0). Monteiro, CBM et al. O valor do eletroencefalograma na avaliação de suspeitas de atraso no desenvolvimento neuropsicomotor em crianças com epilepsia. Rev. Bras. Cresc. e Desenv. Hum. 2010; 20(2): 263-269.
Resumo:Objetivos: avaliar o desempenho do Eletroencefalograma (EEG) na predição de suspeitas de atraso no desenvolvimento neuropsicomotor em crianças menores de cinco anos de idade com triagem positiva para epilepsia. Método: uma amostra de 1687 (73,8%) crianças de uma coorte de nascidos vivos no ano de 2003 em Passo Fundo/RS foi rastreada nos domicílios para detecção de crises convulsivas. Os casos identificados foram encaminhados para a Entrevista Neurológica para Epilepsia, avaliação do desenvolvimento neuropsicomotor com o Teste de Denver II e exame eletroencefalográfico. Calculou-se a sensibilidade, a especificidade e valor preditivo do EEG, tomando-se como padrão-ouro a avaliação clínica. Resultados: das 541 (32%) crianças com rastreamento positivo, 59 apresentaram crises convulsivas e 37 realizaram o Teste de Denver II e EEG. Constatou-se 68,9% de EEG alterados e 84,8% de suspeitas de atraso de desenvolvimento, com associação significativa (p<0,03) entre os dois exames. A sensibilidade do EEG foi de 69% e a especificidade de 75%, com VPP de 91%. Conclusão: O estudo demonstrou que o EEG se associa ao diagnóstico precoce de alterações no desenvolvimento neuropsicomotor, ampliando a detecção de casos suspeitos.Palavras-chave: validade dos testes, eletroencefalografia, desenvolvimento infantil. Rev Bras Crescimento Desenvolvimento Hum. 2010; 20(2): 263-269 PESQUISA ORIGINAL ORIGINAL RESEARCH
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