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Influência do ciclo cardíaco no fluxo sanguíneo na vizinhaça da bifurcação ilíaca

Tese de doutoramento em Engenharia Mecânica (área de conhecimento em Mecânica de Fluídos e Transferência de Calor) ; As doenças cardiovasculares são a principal causa de morte na Europa e nos Estados Unidos da América. Uma das doenças cardiovasculares mais comuns é a aterosclerose, que se caracteriza pela presença de depósitos na camada mais interna das paredes das artérias de pequeno e médio tamanho, inclui...

Using a nitrilase for the surface modification of acrylic fibres

The surface of an acrylic fibre was modified with a commercial nitrilase (EC 3.5.5.1). The effect of fibre solvents and polyols on nitrilase catalysis efficiency and stability was investigated. The nitrilase action on the acrylic fabric was improved by the combined addition of 1 M sorbitol and 4% N, N-dimethylacetamide. The colour levels for samples treated with nitrilase increased 156% comparing to the control...

Cutinase : a new tool for biomodification of synthetic fibers

This paper describes two methods to monitor esterase hydrolysis at the surface of polyester fibres (PETPolyethylene terephthalate). The hydroxyl groups were determined on the fibre surface by alkaline reaction with a reactive dye (CI Reactive Black 5) and colour intensity was determined using a reflectance spectrophotometer. The terephthalic acid solution formed was also quantified after reaction with peroxide ...

Estabilização de enzimas para modificação de fibras sintéticas

A qualidade e as propriedades de processamento das fibras têxteis podem ser melhoradas modificando a superfície do polímero. Grande parte dos métodos convencionais descritos na literatura, requer agentes químicos com efeitos negativos para o ambiente. Estes podem ser evitados aplicando novas técnicas de processamento do polímero baseadas em biotecnologia. Neste trabalho estudou-se a estabilidade de enzimas hidr...

Recycling of textile bleaching effluents for dyeing using immobilized catalase

Catalase was immobilized on alumina carrier and crosslinked with glutaraldehyde. Storing stability, temperature and pH profiles of enzyme activity were studied in a column reactor with recirculation and in a batch stirred-tank reactor. The immobilized enzyme retained 44% of its activity at pH 11, 30 °C and 90% at 80 °C, pH 7. The half-life time of the immobilized catalase was increased to 2 h at pH 12, and 60 °...

Studies of stabilization of native catalase using additives