Percorrer por autor "Costa, Roberto Germano"
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- Caracterização do perfil lipídico e glicémico numa população de BragançaPublication . Costa, Roberto Germano; Pombo, Graça; Ferreira, Isabel C.F.R.A dislipidémia é caracterizada por níveis anormais de lípidos ou lipoproteínas no sangue, que podem estar associadas a manifestações clínicas diversas, tais como: enfartes do miocárdio, acidentes vasculares cerebrais ou doenças vasculares periféricas. No entanto, a detecção precoce de níveis séricos elevados de colesterol torna possível identificar um importante factor de risco modificável para as doenças arteriais coronárias. A ingestão calórica excessiva com alto teor de lípidos afecta os níveis plasmáticos de colesterol total, bem como da fracção de colesterol da lipoproteina de baixa densidade (c-LDL). Embora o colesterol total seja o primeiro lípido sanguíneo medido para avaliar o risco de doença coronárias aterosclerótica, devido à facilidade da sua aferição, utilizam-se também as determinações de c-LDL e de triglicéridos, que actuam como factor de risco, da lipoproteína de alta densidade (c-HDL), que actua como factor de protecção e da lipoproteina de muito baixa densidade (c-VLDL), precursor do c-LDL. A diabetes melitus (DM) é uma doença metabólica caracterizada por hiperglicemia, que ocorre por defeitos na acção e/ou secreção de insulina e está associada ao surgimento de complicações crónicas microvasculares (nefropatia, retinopatia) e macrovasculares (doença arterial coronária, acidente vascular cerebral e doença macrovascular periférica), além de neuropatia diabética. Atingir e manter as concentrações plasmáticas de glucose o mais próximo possível da normalidade é crucial para prevenir e/ou retardar o aparecimento das complicações crónicas da DM. A obtenção de um controle glicémico intensificado, associada ao controle dos lípidos séricos, da pressão arterial e à manutenção de um peso corporal adequado, é um dos principais objectivos destes pacientes.
- Intersubject variability of blood analysis reference values: assessment of age and locality influence by means of a linear discriminant analysis modelPublication . Barreira, João C.M.; Costa, Roberto Germano; Pombo, Graça; Ferreira, Isabel C.F.R.Glycemic and lipidic profiles might be influenced by several factors. The fact that the age group might alter the most extensively evaluated lipidic and glycemic parameters is a more or less well accepted fact. To verify this empirical notion, 996 human subjects aged between 21 and 90 years from different localities were characterized according to age. To assess lipid profile, total cholesterol and cholesterol associated with lipoprotein fractions (c-LDL and c-HDL) and triglycerides were determined. Regarding glycemic profile, glucose and glycated hemoglobin were measured. The majority of the population had values of lipidic parameters fit into the reference values, presenting low or moderate risk for developing cardiovascular disease. Blood glucose was often far above the desirable, but this can be devalued due to the HbA1c values, which were overwhelmingly located in the normal range. The categorization of data in different age groups did not allow defining statistically significant differences. Despite the discriminant linear model was presented, the results indicate that age group did not act as a strong discriminant factor. Somehow unexpectedly, the most significant differences were found among the different localities, which tended to show a similarity according with their latitude. Furthermore, there were no significant correlations in the parameters associated with lipidic profile, but there was a direct correlation between glucose levels and HbA1c (glycemic parameters).
- Optimization of hemp (Cannabis sativa L.) mechanical and physical propertiesPublication . Bueno, Guilherme Irigoyen; Ribeiro, J.E.; Costa, Roberto Germano; Rocha, JoãoNatural fibers are an alternative to the traditional synthetic fibers used for industrial applications and as reinforcement of composites material. Compared to synthetic fibers, the advantages of using natural fibers are their renewability, recyclability, low density, availability in large amounts and low cost [1]. Hemp fiber is used in many applications, it is particularly attractive to reinforcement of composites materials [2]. In this context, a mechanical and physical characterization has been made with hemp fibers grew in Bragança and Mirandela, regions from Portugal, in different conditions of nitrogen fertilization, sowing density, extraction method, and grew location. The objective of the study was to assess the effects of these parameters for optimizing the mechanical properties of hemp fibers. Tensile strength and Young's modulus were determined according to ASTM C1557 [3], density tests were made using a water pycnometer. Average value for tensile strength was 565.3 ± 167.0 MPa, average density was 1.65 ± 0.25 g cm-3 and average Young’s modulus was 92.4 ± 7.4 GPa. A statistical analysis of all parameters was made using ANOVA. The influence of all parameters was determined, the most influent parameter was extraction method and the combined effect of sowing density and nitrogen fertilization, with high influence in specific tensile strength and tensile strength, respectively. Optimal parameters for higher tensile strength were obtained for sowing density of 100 Kg ha-1, nitrogen fertilization of 50 Kg ha-1, extracted with water, cultivated in Bragança. Lower density values were obtained for sowing density of 25 Kg ha-1, nitrogen fertilization of 100 Kg ha-1, extracted with water, cultivated in Bragança. Higher Young's Modulus was determined for fibers from Bragança, with sowing density of 50 Kg ha-1, nitrogen fertilization of 50 Kg ha-1 and extracted with water.
- Performance and ruminal and intestinal morphometry of Santa Inês sheep submitted to feed restriction and refeedingPublication . Lima, Hugo Batista; Costa, Roberto Germano; Dias-Silva, Tairon Pannunzio; Cruz, George Rodrigo Beltrão da; Carvalho, Francisco Fernandes Ramos de; Guerra, Ricardo Romão; Ribeiro, Neila Lidiany; Araújo Filho, José Teodorico de; Teixeira, AlfredoA study was carried out to evaluate the performance and ruminal and intestinal morphology of Santa Inês sheep subjected to feed restriction followed by refeeding. A total of 40 uncastrated lambs with an approximate age of 120 ± 15 days and mean body weight (BW) of 17.04 ± 1.18 kg were randomly divided into two groups of BW (20 and 25 kg of BW), which were subjected to different levels of feed restriction (0%, 25%, and 40% of feed restriction). For performance variables, six treatments were considered (0, 25%, and 40% of feed restriction for both groups (20 and 25 kg of BW)) and five treatments for morphometric variables (ad libitum, 25% and 40% for both groups (20 and 25 kg of BW)). All animals were slaughtered with 14 weeks of experimentation. During the feed restriction phase, the dry matter intake (DMI), feed efficiency (FE), and average daily gain (ADG) decreased (P < 0.05) as the level of restriction increased. During the refeeding phase, lambs with 20 kg of body weight subjected to restriction presented lower (P < 0.05) DMI in the ad libitum treatment. However, lambs with 25 kg of body weight under feed restriction presented DMI, FE, and ADG similar (P > 0.05) to the group ad libitum. The final body weight of restricted lambs after refeeding (both groups 20 and 25 kg of body weight) was lower (P < 0.05) than lambs feed ad libitum. In relation to morphology, restricted lambs showed greater height ruminal papillae and larger (P < 0.05) area of ruminal absorption and intestinal absorption, especially the lambs under treatment 40% of feed restriction. The feed restriction followed by refeeding in sheep provided partial compensatory gain, in addition, caused morphological changes in the rumen and intestine that allowed greater absorption and possibly compensatory gain in periods of greater refeeding.