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  • Hyaluronic acid and collagen extraction from chicken combs
    Publication . Soares, Gonçalo Costa; Pintado, Maria Manuela Estevez; Oliveira, Ana Leite; Madureira, Ana Raquel
    Poultry industry is a rising agricultural activity, demanding new alternatives for the valorisation of the generated by-products. Hyaluronic acid (HA) is an important biopolymer which is present in high concentrations in chicken combs. It plays many important roles in the human body, such as in the extracellular matrix, in the skin, in cartilage, in synovial fluid, in fertilization, among others. HA can be used in medical and cosmetic industries with applications for tissue engineering, wound healing, aesthetic treatments, adhesions and scar reduction, molecule delivery, control of stem cell behaviour and ophthalmology. Collagen is one of the most important proteins, having many medical applications as a biomaterial, such as in tissue engineering, in drug delivery systems, in ophthalmology, in wound healing, and others. This thesis aimed to investigate the possibility and optimization of a conjoint extraction of HA and collagen from chicken combs. Extraction optimization was based on Fast Protein Liquid Chromatography analyses, which was also used to confirm the integrity of extracted collagen. In the optimized extraction methodology, chicken combs were subjected to a delipidation process with acetone, followed by three consecutive extractions with 0.5 M aceti c acid for 24 hours, at 4 ºC, which allowed the conjoint extraction of HA and collagen with extractions yields of 0.06 % and 2.71 % in terms of dry weight, respectively. Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry confirmed the presence of both HA and collagen type I in lyophilized powders. HA and collagen can thus be viably extracted from chicken combs, with many possible applications in the biomedical field.
    2017-11-14Dissertação de mestrado Acesso aberto Ver mais
  • A resolução em benefício da massa insolvente : a resolução incondicional
    Publication . Resende, Sara Filipa Gomes; Epifânio, Maria do Rosário
    A presente dissertação versa sobre uma temática de bastante pertinência: a Resolução em Beneficio da Massa Insolvente. Pretende-se uma análise geral do regime, tanto da resolução condicional como incondicional, com uma linha de profundidade alargada relativamente a esta ultima e, forçosamente, às diversas alíneas do art 121º do CIRE. Versaremos sobre a análise comparativa face ao regime do CPEREF, concretizando as alterações essências. Cumpre-nos, também, uma referência aos meios gerais de conservação da garantia patrimonial, de entre os quais se destaca a Impugnação Pauliana, instituto que ao longo deste estudo será comparado ao da Resolução em Benefício da massa insolvente, o que permitirá concluir, desde logo, pela acentuada inovação do atual regime com principal destaque para a exclusão do instituto da Impugnação Pauliana Coletiva.
    2017-11-14Dissertação de mestrado Acesso aberto Ver mais