2 resultados para HETEROGENEOUS POLYMERS

em Universidade Federal do Pará


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Inherited resistance to activated protein C caused by the factor V Leiden (FVL) mutation is the most common genetic cause of venous thrombosis yet described, being found in 20-60% of patients with venous thrombophilia. A relationship between the FVL mutation and an increased predisposition to arterial thrombosis in young women was recently reported. We assessed the prevalence of the FVL mutation in 440 individuals (880 chromosomes) belonging to four different ethnic groups: Caucasians, African Blacks, Asians and Amerindians. PCR amplification followed by MnlI digestion was employed to define the genotype. The FVL mutation was found in a heterozygous state in four out of 152 Whites (2.6%), one out of 151 Amerindians (0.6%), and was absent among 97 African Blacks and 40 Asians. Our results confirm that FVL has a heterogeneous distribution in different human populations, a fact that may contribute to geographic and ethnic differences in the prevalence of thrombotic diseases. In addition, these data may be helpful in decisions regarding the usefulness of screening for the FVL mutation in subjects at risk for thrombosis.

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The possibility of recycling and the favorable mechanical properties of the products have encouraged the study and production of thermoplastic composites from natural fibrous waste. Açaí (cabbage palm) fiber, which is removed from the seed, has been slightly investigated, as compared to what is already known about the fruit pulp. In this study, the influence of açaí fiber as an element of reinforcement in recycled everyday usage thermoplastics using simple, low cost methodology was evaluated. Recycled matrixes of high impact polystyrene and polypropylene were molded by hot compression from which the fiber composites were obtained. The FTIR technique showed that the process was efficient in preventing degradation of the açaí fibers. The influence of the fiber on the mechanical behavior of the recycled matrixes was investigated by microscopic images of compression and impact tests. The results showed better impact performance for the fiber combined with the polymeric matrixes.