Densidade e velocidade do som em soluções aquosas de sulfato de amónio contendo serina ou treonina

Neste trabalho faz-se uma breve apresentação das aplicações industriais dos aminoácidos e relevância do estudo de soluções aquosas contendo aminoácidos, em particular da serina ou da treonina. Estudar a interação de compostos modelo é importante pois tanto os aminoácidos, como péptidos, e seus derivados, constituem parte das estruturas das proteínas. Nesse sentido, foram estudadas as metodologias experimentais que permitem determinar a densidade e a velocidade do som. As propriedades derivadas como volumes molares parciais e compressibilidade adiabática são interpretadas em termos de química-fisica das soluções. Neste trabalho foram realizadas medições experimentais da densidade e velocidade do som em soluções aquosas de sulfato de amónio, a diferentes molalidades, contendo serina ou treonina, a cinco temperaturas diferentes, numa gama entre 278.15 K a 318.15 K. A partir destes dados, foram calculados os volumes molares parciais dos aminoácidos em estudo, de modo a compreender as propriedades físico-químicas das soluções. É também apresentado todo o desenvolvimento experimental, bem como os resultados obtidos e a interpretação teórica dos fenómenos. This work makes a brief presentation of industrial applications and relevance of amino acids, and studies of aqueous solutions containing amino acids, in particular with serine or threonine. The study of model compounds such as amino acids, peptides or their derivatives, as they constitute part of protein structures, is of extreme importance. Accordingly, the experimental methodologies for measuring the density and sound speed were studied. The properties derived such as partial molar volumes and adiabatic compressibility are interpreted in terms of the physical-chemistry of solutions. In this work, experimental values for the density and speed of sound in aqueous solutions of ammonium sulphate at different molalidades, containing serine or threonine, at five different temperatures in a range between 278.15 K to 318.15 K were measured. From these data, partial molar volumes of the amino acids were calculated. From the detailed analysis of that data the physical-chemistry of the solutions was interpreted. It is also presented, carefully, the intensive experimental development, adapted protocol and the theoretical analysis and graphical interpretations of phenomena

Xenografting as a Tool to Preserve Endangered Species: Outcomes and Challenges in Model Systems

The use of testis tissue xenografting as a valuable tool to rescue endangered and genetically valuable individuals that die young or otherwise fail to produce sperm has been the subject of much interest. Although the technique has been successfully applied to a wide variety of species, little is known about what determines the outcome. Furthermore, to improve the applicability of xenografting, new methods to preserve and transport testis tissue from valuable animals are emerging. However, one major issue remains: the application of xenografting implies the development of subsequent ART techniques to produce offspring from the recovered material. This paper focuses on these three aspects of testis tissue xenografting as a tool for rescuing endangered and valuable genetic pools

Thrombotic genetic risk factors and warfarin pharmacogenetic variants in São Miguel's healthy population (Azores)

<p>Summary</p> <p>Background</p> <p>The Azorean population presents the highest standardized mortality rate for cardiovascular diseases (CVD) when compared to mainland Portugal and other populations. Since thrombosis is a common cause of CVD, we assessed four polymorphisms in three thrombotic risk genes – <it>F5 </it>(G1691A), <it>F2 </it>(G20210A) and <it>MTHFR </it>(C677T, A1298C), in 469 healthy blood donors from São Miguel Island (Azores). We also analysed the <it>CYP2C9 </it>(C430T, A1075C) and <it>VKORC1 </it>(G1639A) variants in fifty-eight individuals with predisposition to thrombosis (possessing at least one variation in <it>F5 </it>or <it>F2 </it>genes and one in <it>MTHFR</it>) to evaluate their warfarin drug response genetic profiles.</p> <p>Results</p> <p>Among the 469 individuals, the data showed that thrombotic risk allele frequencies – 1691A (4.9%), 20210A (1.8%), 677T (41.7%) and 1298C (24.8%) – were similar to other Caucasians, but significantly different from mainland Portuguese (χ², <it>p </it>< 0.001). The combined analysis of these variants identified twenty-two different genetic profiles (genotype order: <it>F5</it>, <it>F2</it>, <it>MTHFR </it>C677T and A1298C). Complete homozygosity for all wild-type alleles (GG GG CC AA) was present in 11.7%, being GG GG CT AA (22.4%) the most frequent profile. The results also demonstrated that 12.4% (58 out of 469) of São Miguel islanders have increased genetic predisposition to thrombosis. Subsequently, we evaluated these individuals for their warfarin response genetic profiles. The data showed that seven out of fifty-eight individuals are poor metabolizers (two with <it>CYP2C9</it>*2/*2 and five with <it>CYP2C9</it>*2/*3 genotypes). <it>VKORC1 </it>polymorphism analysis identified twelve individuals (20.7%) with AA genotype, who probably will require lower doses of warfarin. The joint analysis of <it>CYP2C9 </it>and <it>VKORC1 </it>revealed that 79.3% (46 out of 58) of the individuals carry at least one polymorphism in these genes. Within these, twenty-five individuals (43.1%) need intermediate and/or low doses of warfarin, if treatment is started.</p> <p>Conclusion</p> <p>The present study demonstrated, for the first time, that São Miguel, and possibly the Azores population, shows significant differences on allele frequencies of thrombotic risk factors when compared to mainland Portugal. This research constitutes a primary approach for future studies on CVD, as well as for the implementation of warfarin dosing protocols using the patient's genotypic information.</p

Effects of intervention programs on child and adolescent BMI: a meta-analysis study

This meta-analysis study aims to assess the efficacy of school-based and after-school intervention programs on the BMIs of child and adolescents, addressing the correlation between some moderating variables. Methods: We analyzed 52 studies (N = 28,236) published between 2000-2011. Results: The overall effect size was 0.068 (P < .001), school (r = .069) and after-school intervention (r = .065). Programs conducted with children aged between 15-19 years were the most effective (r = .133). Interventions programs with boys and girls show better effect sizes (r = .110) than programs that included just girls (r = .073). There were no significant differences between the programs implemented in school and after-school (P = .770). The effect size was higher in interventions lasting 1 year (r = .095), with physical activity and nutritional education (r = .148), and that included 3-5 sessions of physical activity per week (r = .080). The effect size also increased as the level of parental involvement increased. Conclusions: Although of low magnitude (r = .068), the intervention programs had a positive effect in prevention and decreasing obesity in children. This effect seems to be higher in older children's, involving interventions with physical activity and nutritional education combined, with parent's participation and with 1-year duration. School or after-school interventions had a similar effect

Successes and Challenges of Food Market Reform: Experiences from Kenya, Mozambique, Zambia, and Zimbabwe

Agricultural and Food Policy, Downloads July 2008-July 2009: 38,

Association between dietary calcium intake and blood pressure among portuguese children

Higher blood pressure (BP) in childhood is associated with cardiovascular risk. It has been described that dietary calcium intake may affect BP regulation. The objective of this study was to analyze the association between dietary calcium intake and BP in children.info:eu-repo/semantics/publishedVersio

Adiposity indicators and cardiovascular risk factors in Azorean adolescents

This study was conducted to evaluate the association of adiposity indicators (body mass index, waist circumference and waist-to-height ratio) with cardiovascular risk factors in lean andobese Azorean adolescents.info:eu-repo/semantics/publishedVersio

Ability of Different Measures of Adiposity to Identify High Metabolic Risk in Adolescents

Introduction. This study aimed to evaluate the screening performance of different measures of adiposity: body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) for high metabolic risk in a sample of adolescents. Methods. A cross-sectional school-based study was conducted on 517 adolescents aged 15–18, from the Azorean Islands, Portugal. We measured fasting glucose, insulin, total cholesterol (TC), HDL-cholesterol, triglycerides, and systolic blood pressure. HOMA and TC/HDL-C ratio were calculated. For each of these variables, a Z-score was computed by age and sex. A metabolic risk score (MRS) was constructed by summing the Z-scores of all individual risk factors. High risk was considered when the individual had ≥1SD of this score. Receiver-operating characteristics (ROC) were used. Results. Linear regression analyses showed that, after adjusting for age and pubertal stage, all different measures of adiposity are positively and significantly associated with MRS in both sexes, with exception of WHtR for boys. BMI, WC, and WHtR performed well in detecting high MRS, indicated by areas under the curve (AUC), with slightly greater AUC for BMI than for WC and WHtR in both sexes. Conclusion. All measures of adiposity were significantly associated with metabolic risk factors in a sample of Portuguese adolescents