Repositório RCAAP

We present detailed simulation results of localised hemodynamics for a cluster of rolling leukocytes under shear-thinning blood flow using a lattice Boltzmann model. Leukocytes were modelled as hard spheres moving through a venule of rigid walls. The used hemorheological parameters were obtained from in vivo measurements in blood samples of Wistar rats. Velocities, shear stresses and torques were computed and visualised for each individual cell, for the cluster and for the fluid. We have found that the flow is mainly three-dimensional due to the swirling and the asymmetry of the formed vortices during the recruitment process. The shear stress is maximum on a cap covering the cell and a cone with its base on the endothelial wall at the contact region. The leukocyte is recruited to the wall with the aid of trapping vortices and four stagnant regions surrounding the cell in addition to lateral motion towards the wall. We suggest that these phenomena are highly dependent on the angular velocity of the leukocyte and on the attractive force between the leukocyte and the endothelial wall. For a moving cluster of recruited leukocytes, velocities and shear stresses as well as torques are computed. It was found that the shear stress at the endothelium gets higher as the cluster moves in the main stream enabling early initialisation of the rolling process.

Sport participation has been advocated as a strategy to improve adolescents' mental health. However, how these variables evolve during the adolescent years is uncertain. The objective of the present work was to examine the longitudinal associations of sports participation and depressive symptoms in adolescents. Participants were 525 Spanish adolescents (50.3% boys), aged between 12 and 15 years old (M = 13.45, SD = 0.69). They were enrolled in 18 secondary schools located in Andalusia (Spain) in the first two academic years of Compulsory Secondary Education. Data were collected in three waves, separated by one year, by administering self-report measures of depressive symptoms and sport participation. Repeated measures analyses of variance were conducted to examine the change in depressive symptoms and sport participation, and a latent growth curve model was tested to examine the change in depressive symptoms controlling initial sport participation and gender. At each wave, more frequent sport participation was related to lower depressive symptoms. Two years after the first assessment, adolescents became more depressed but not more active. Less active adolescents had more depressive symptoms in each assessment time. At all moments of assessment, girls were less active and reported more depressive symptoms. Moreover, girls had a higher increase in depressive symptoms than boys. Promotion of physical activity (PA) as a mental health strategy needs to consider gender differences as boys and girls have different patterns of presentation of depressive symptoms throughout adolescence.

O presente estudo subordina-se à análise do contrato de cash pooling. O seu estudo justifica-se pelo facto do contrato de cash pooling constituir um verdadeiro meio alternativo de financiamento, que visa gestão consolidada da tesouraria de um grupo de sociedades e justifica-se pela necessidade de evitar-se custos inerentes ao financiamento externo, bem como minimizar o valor dos juros, que aumentaram, fruto da crise no sector financeiro. Entretanto, a nossa pesquisa procura demonstrar que os principais motivos que norteiam a implementação do contrato de cash pooling, devem ser confrontados com os entraves estabelecidos pela lei das sociedades comerciais, bem como pela lei das instituições financeiras. A primeira abordagem, vai no sentido de apresentar a figura, o seu conceito, as suas modalidades, modo de funcionamento e a natureza jurídica da figura. É também feita uma análise do direito comparado do sistema de cash pooling, a nível dos países africanos francófonos, em países como a África do Sul e Nigéria que demonstram um estudo superficial da figura e de países da Europa, onde o estudo da figura tem-se mostrado mais desenvolvido. Finalmente, no terceiro capítulo será feita uma abordagem aos problemas jurídicos que a implementação da figura de cash pooling pode provocar ao ordenamento jurídico Angola, bem como as possíveis soluções para resolução destes problemas, com vista a alcançar os objectivos das sociedades participantes no grupo.

The Blockchain technology that revolutionized the world was launched in 2008 with the publication of the paper undertitled ‘Bitcoin: A Peer-to-peer Electronic Cash System’, by the enigmatic pseudonym of Satoshi Nakamoto, which described a version of electronic cash that allowed online payments to be directly made from one party to another. Succeeding the ground-breaking transformation that was carried out, cryptocurrencies commenced to shift the monetary system to a predominantly digital one, more adapted to the reality of a fast, technological, audacious and computerized world, interconnected by the largest and worldwide network ever seen. Behind this ingenious structure comes the concept of Blockchain, Virtual Currencies and Distributed Ledger Technology (DLT), innovative and high-tech tools of security and storage that aim to reduce mistakes, frauds and costs. Decentralization, transparency and immutability are the three pillars that allow the safekeeping of private relations in order to generate confidence, reduction of finance transaction costs as well as reinforce any and all public relations involved. On the other hand, these revolutionary novelties follow an unregulated social pattern, fostering an unbridled advance by generating vast uncertainties, diversity and asymmetries. In order to reduce its vulnerabilities, these technologies are in most need of a financial and tax regulatory effort to align them under a uniform concept, as well its main characteristics and aptitudes. Beyond the legislative and conceptual approach, the challenges of a digital era and the financial revolution lead the world to innovative methods to solve issues that have arisen. The Blockchain, DLT and Virtual Currencies provide transformation and key answers that might contribute to efficient, scientific and solid solutions in real-time to governmental activities, specially tax administrations. Considering its foremost democratic and accountable features, they can be used in e-identities, personal records, assets inventories, citizenships, border control, tax transparency, financial and tax compliance, and especially smart contracts on public administration. From this perspective, it is key to scrutinize the efficiency of the new world’s Blockchain paradigm in order to verify its utmost reliability prospective.

An exaggerated accumulation of type I and type III fibrillar collagens occurs throughout the free wall and interventricular septum of patients with primary hypertension and left ventricular hypertrophy (LVH). In the present study the serum concentration of procollagen type III amino terminal peptide (PIIIP) was measured to determine the value of this peptide as a potential marker of ventricular fibrosis in hypertensive patients, particularly those with LVH.

Objective: Physical fitness (PF) and physical activity (PA) are inversely associated with body mass index and waist circumference (WC), whereas sedentary time (ST) seems to boost obesity in youth. The aim was to examine the associations of each selected PF test, PA-related exposures, and specific ST patterns with obesity and determine the most relevant ones, in a large sample of a school-aged adolescent. Methods: The sample consisted of 2696 Portuguese youth aged 10 to 18 years. Height, weight, and WC were measured. PA and ST components were measured using accelerometry. PF was evaluated using a battery of tests. Results: The Progressive Aerobic Cardiovascular Endurance Run (PACER) and push-up tests seemed to be the exposures that presented the strongest and more consistent associations with obesity, independent of PA/ST profiles (P < .05). The second exposure of relevance for adolescent obesity level was the breaks in ST with a negative relationship regardless of PA/PF profiles (P < .05). Finally, ST accumulated in periods of <30 minutes, and moderateto-vigorous PA were favorably associated with obesity, independent of ST/PF. Conclusions: Independent of PA and ST, cardiorespiratory fitness (CRF), measured by PACER, was associated with obesity markers. This may be in part due to the dependence of PACER performance on adiposity. Also, limiting prolonged ST and promoting interruptions in this behavior were associated with obesity. These associations suggest that future research should examine other strategies beyond PA promotion for tackling obesity that consider CRF and breaking ST.

The use of aspirin, while well established in the secondary prevention of cardiovascular events, remains controversial in the primary prevention of these events in the general adult population. In this setting, aspirin showed a significant but modest decrease of cardiovascular event incidence at the cost of a significantly increased risk of bleeding, a pattern that is also seen in higher risk patients, such as diabetics. It becomes exceedingly important to identify other patient clusters that would benefit from cardiovascular risk reduction at the best benefit/risk ratio.

The aim of this work is to study the relationships between blood pressure profile, cardiac manifestations of high blood pressure and P-III-P as an index of fibrosis. We studied hypertensives without other diseases using echocardiography (M and B mode, and Doppler), ABPM using a Spacelabs 9000, and plasma levels of P-III-P. The model ANOVA, one way, was used for the statistical analysis. The level of significance was accepted for p<0.01 (two-tailed probabilities). The 73 hypertensives studied were divided in two subgroups: dippers (49 subjects) and non-dippers (21 subjects). The non-dipper group had an higher degree of left ventricular hypertrophy obtained by the higher measurement of the inter-ventricular septum thickness (p<0.01), posterior wall thickness (p<0.01), and an higher index of left ventricular mass (p<0.01) then the dippers, they also had higher levels of fibrinogen (p<0,01) and higher plasma levels of P-III-P then dippers (p<0.01). It was found a correlation between the fibrinogen, P-III-P levels and index of left ventricular mass (p<0,01). In conclusion, P-III-P might be a marker of tissue lesion, and fibrinogen might be a plasma marker of gravity of hypertension. This gravity can be express by the degree of left ventricular hypertrophy.

Purpose: Acanthosis nigricans (AN) is a hyperpigmented dermatosis associated with obesity and insulin resistance (IR). There is no consensus whether AN extension scoring offers added value to the clinical estimation of IR. In this study we aimed to assess and score AN using both a short and an extended version of the scale proposed by Burke et al. and analyze the relationships of both versions with hyperinsulinemia and IR. Methods: We analyzed data from 139 overweight adolescents (body mass index ≥85th percentile) aged 12–18 with (n=67) or without (n=72) AN who were followed at a pediatric obesity clinic. Results: Adolescents with AN had higher levels of insulin (d=0.56, P=0.003) and HOMA-IR (d=0.55, P=0.003) compared to those without. Neither the short nor the extended versions of AN scores explained either hyperinsulinemia (β=1.10, P=0.316; β=1.15, P=0.251) or IR (β=1.07, P=0.422; β=1.10, P=0.374). The presence of AN alone predicted hyperinsulinemia and the presence of IR in 7.3% (β=2.68, P=0.008) and 7.1% (β=2.59, P=0.009) of adolescents, respectively. Conclusion: Screening for AN at the neck and axilla is a noninvasive and cost-effective way to identify asymptomatic overweight adolescents with or at risk of developing IR.

Este relatório descreve o trabalho realizado no âmbito da disciplina de Projecto em Engenharia Informática do Mestrado em Engenharia Informática da Faculdade de Ciências da Universidade de Lisboa (FCUL), no período decorrente entre 3 de Setembro de 2007 e 3 de Junho de 2008. O projecto surge no contexto do sistema das Declarações Electrónicas (DE), do Sistema de Gestão dos Impostos do Património (Sistema do Património), do Sistema Value Added Tax on E-Services (VAT) e do Sistema de Controlo e Gestão (SCG). Os três primeiros sistemas integram-se ambos na Direcção-Geral dos Impostos (DGCI), tendo como objectivo facilitar o relacionamento dos contribuintes com a DGCI permitindo, em particular, a entrega do imposto Municipal sobre Transmissões Onerosas de Imóveis (IMT) e do Imposto sobre o Valor Acrescentado pela Internet. Por sua vez, o SCG é um sistema interno desenvolvido pela Opensoft. Sobre estes sistemas foram desenvolvidos os projectos: “Casa Pronta” nas DE e Sistema do Património, “Processos Periódicos” no SCG, “Acessibilidade VAT” no sistema VAT, Sistema de Gestão de Remunerações de Peritos (SIREP) e “Porta 65 Jovem” no Sistema do Património. O desenvolvimento destes projectos envolveu tarefas relacionadas com a análise, implementação, testes e avaliação. Na fase da análise foram estudados os requisitos das aplicações (escolha de interfaces, definição do formato de ficheiro, protocolos de comunicação e descrição funcional). Na fase de implementação foram explicados, com detalhe, quais os passos tomados no decorrer dos projectos assim como as decisões tomadas e respectivas consequências.

The PTEN proteins (PTEN, for phosphatase and tensin homolog deleted on chromosome ten) are a family of multi-specific phosphatases able to use both lipidic and proteic substrates (for recent reviews on their biochemistry and biomedical relevance see, e.g. The most important physiological PTEN substrate is the lipidic second messenger phosphatidylinositol-3,4,5-trisphosphate (PIP3). Thus, PTEN reverts the phosphoinositide-3-kinases (PI3K) phosphorilation of phosphatidylinositol-4,5-bisphosphate (PIP2) to PIP3. As PIP3 activates the serine–threonine kinase Akt, which is involved in anti-apoptosis, proliferation and oncogenesis, its dephosphorylation by PTEN negatively regulates tumorigenesis. Mutations in the PTEN gene in human can lead to sporadic cancers (e.g., glioblastoma, endometrial and prostatic cancers) or to hereditary disorders characterized by multiple hamartomas and increased risk of cancers (Cowden disease, Bannayan-Zonana syndrome and Lhermitte-Duclos disease). PTEN expression is also associated with neuronal differentiation, and G1 phase cell cycle arrest in cell cultures.

Timolol maleate is a compound used in treatment for reducing increased intra-ocular pressure by limiting aqueous humor production. Decreased erythrocyte deformability (ED), increased activity of erythrocyte acetylcholinesterase (AChE), increased values of nitrosoglutathione (GSNO) and nitic oxide (NO) and decreased plasma levels of NO metabolites, were described in primary open angle glaucoma patients. In healthy human red blood cells (RBCs), timolol is an inhibitor of AChE and induces NO efflux and GSNO efflux from that blood component in lower concentration than those obtained in presence of the natural AChE substrate, acetylcholine (ACh). The signal transduction pathway in RBCs described for NO in dependence of AChE-ACh active complex involves Gi protein, protein tyrosine kinase (PTK like Syk and p53/56Lyn), protein tyrosine phosphatase (PTP) and adenylyl cyclase (AC).The aim of this in vitro study was to verify the effect of timolol maleate in ED, NO efflux and NO derivatives molecules (NOx) like nitrite (NO2-), nitrate (NO3-, peroxynitrite (-ONOO) and GSNO under the presence of PTK, PTP, AC and guanylyl cyclase (GC) enzyme proteins inhibitors.Blood samples from healthy donors were each one divided and were performed aliquots in absence (control aliquots) and presence of timolol or timolol plus each inhibitor and Gi protein uncoupling. No significant differences in erythrocyte NO efflux, GSNO, peroxynitrite, nitrite and nitrate concentrations in response to timolol when compared with the untreated blood samples aliquots were obtained.It was observed an increase in erythrocyte deformability at high shear stresses induced by the simultaneous presence of timolol and band 3 protein dephosphorylation by PTK syk inhibitor. No significant differences where verified in peroxynitrite levels in the blood aliquots in presence of timolol plus each enzyme inhibitor and Gi protein uncoupling in relation to the control aliquots. No variation of GSNO concentration occurs under the presence of timolol and AMGT (PTK lyn inhibitor) besides the significant higher values observed with each one of the other inhibitors. Nitrate concentration increases significantly in all aliquots with timolol plus each one of the inhibitors. The same was observe with nitrite levels with exception of the aliquots with timolol plus AMGT or timolol plus Gi protein uncoupling showing no significant values in relation to the control aliquots.Besides the changes in NO derivative molecules and NO efflux from RBCs obtained in this study with blood samples of healthy donors under the effect of timolol plus each inhibitor of the proteins participants in NO signal transduction mechanism, further analogue studies must be promoted with blood samples of patients with glaucoma or any other inflammatory vascular disease.

O objectivo da Newsletter do Instituto de Saúde Baseado na Evidência (ISBE) é a disponibilização de informação sobre áreas relevantes para a prática clínica, baseada na melhor evidência científica. São localizados estudos relevantes e de alta qualidade, criticamente avaliados pela sua validade, importância dos resultados e aplicabilidade prática e resumidos numa óptica de suporte à decisão clínica. É dada prioridade aos estudos de causalidade – revisões sistemáticas, ensaios clínicos, estudos de coorte prospectivos/retrospectivos, estudos seccionais cruzados e caso‐controlo – incluindo‐se ainda, quando justificado, estudos qualitativos considerados de elevada qualidade metodológica e importância clínica.

Children's sleep habits are profoundly affected by socio-economic, cultural, and environmental factors. We aim to describe the sleep habits of pediatric sub-populations from Cape Verde and Mozambique using the Children's Sleep Habits Questionnaire, and to ascertain the determinants of the questionnaire's score. Material and Methods: We conducted cross-sectional surveys in surveillance appointments in Cape Verde and in a school in Maputo (Mozambique). The Cape Verde sample included 206 children (mean age: 6.5) and the Mozambique sample 454 children (mean age: 8). The Portuguese version of the Children’s Sleep Habits Questionnaire was used to evaluate the children’s sleep habits. The distributions of the questionnaire’s scores across different levels of the demographic variables were compared using the Mann-Whitney and the Kruskal-Wallis tests. We used regression models to quantify the relationship between the demographic variables and the questionnaire’s scores. Results: Cape Verde sample: Questionnaire median score: 50 (range 36 – 81). Prevalence of sleep problems: 29.9% (cut-off = 56). Prevalence of parent-reported sleep problems: 22.8%. Co-sleeping: 63%. Bedtime television: 30%. Daytime nap: 63%. Questionnaire scores are associated with the mother’s educational level, the children’s age group, and with the frequency of daytime napping. Mozambique Sample: Median Questionnaire score: 48 (range 35 – 77). Prevalence of sleep problems: 28.4% (cut-off: 52). Percentage of parent-reported sleep problems: 6.9%. Co-sleeping: 29%. Bedtime television: 33%. Daytime nap: 23%. Questionnaire scores are associated with the mother’s nationality, the father educational level, and with the frequency of bedtime television. Discussion: Parents tend to overestimate the quality of their children’s sleep. The prevalence of sleep disturbances and the cut-off values are higher than observed in previous studies, which may be due to the existence of different standards and cultural expectations across populations. Bedtime television, typically associated with more disturbed sleep, is frequent in both samples. Co-sleeping and daytime napping are frequent in the Cape Verde sample; wetting the bed is common and more prevalent than in previous studies. Bed-sharing increases the parents’ awareness of their children’s sleep quality, contributing to the high prevalence of parent-reported sleep problems. Conclusion: Parent-reported sleep problems underestimate the Children’s Sleep Habits Questionnaire results. This is not necessarily indicative of more disturbed sleep and might reflect differences in sleep behavior, childcare practice, and cognitions and attitudes towards the concept of ‘normal’ sleep.

The 24 hours ABPM has allowed the discrimination of hypertensive patients in dippers and non-dippers. Being the last ones associated with a higher number of cardiac and vascular repercussions. The objective of the present work is to evaluate the haemomeologic alterations in hypertensive patients and to determine if there are differences of haemorheologic parameters between these two groups.

Introduction: The 24 hours monitoring blood pressure has allowed the discrimination between hypertension and white coat hypertension. Several works have shown haemorheolyic alterations in hypertensive patients, which might be related with the increased risk for cardiovascular events. The objective of the present work was to evaluate if any alteration in haemorheologyc parameters was present in the WCH.

O estudo in vivo ou in vitro da produção de monóxido de azoto (NO) em células endoteliais requer o uso de eléctrodos específicos de NO, que permitem compreender melhor os mecanismos de transducção de sinal a nível intracelular. Neste trabalho estudou-se a hipótese da acetilcolina (ACh) ser um modulador do metabolismo do NO através da acetilcolinesterase (AChE), funcionando como receptor de transducção de sinal para este mensageiro intracelular, utilizando a velnacrina maleato como inibidor da AChE. As células endoteliais da veia do cordão umbilical humano (HUVECs) em cultura foram estimuladas com ACh 10-5M e velnacrina maleato 10-5M (VM), medindo-se a produção e/ou libertação de NO pelas HUVECs, utilizando um eléctrodo sensor de NO. Os resultados obtidos de concentração de NO nas HUVECs foram de 1,83 ± 0,54 nM (n=5) na presença de ACh 10-5M e de 0,83 ± 0,19 nM na presença de VM 10-5M. Com a adição simultânea destes dois compostos obteve-se uma concentração de NO de 1,12 ± 0,18 nM. A presença de VM inibe significativamente o efeito que a ACh produz no aumento da concentração de NO (P=0,009). Os resultados experimentais permitem chegar à conclusão que a formação do complexo AChE-velnacrina maleato pouco activo interfere com mecanismos de transducção de sinal desconhecidos. A hipótese colocada de que a acetilcolina modula o metabolismo do NO, através da acetilcolinesterase, podendo funcionar como receptor de transducção de sinal, parece ser válida embora o seu mecanismo continue a ser desconhecido.

Red cell acetylcholinesterase (AChE) and Na, + K + - adenosinetriphosphatase (ATPase) activities, cell 2,3 - diphosphoglycerate (2,3 - DPG) and adenosinetriphosphate (ATP) content and filterability ratio were studied in two children (with moderate hemolytic anemia and marked spherocytosis) and their parents. Patients’ parents have no medical problem but evidenced discrete spherocytosis on peripheral smear. Except some increased apparent red cell rigidity detected in the father, all the parameters studied in both parents were found to be normal, as compared to healthy controls. In contrast, red cell rigidity, 2,3-DPG and ATP levels and Na, + K + ATPase activity were increased in both children, whereas AChE activity was similar to values of normal subjects. These observations suggest that both affected patients suffered from homozygous hereditary spherocytosis linked to an apparently recessively inherited red cell membrane defect.

In addition to the suggestive involvement of the noradrenergic system, there is substantial evidence that blood pressure regulation in the man and some other mammais (e.g.cat, dog and rat) is dependent on the cholinergic activity. Many experimental and some clinical studies have demonstrated that the stimulation of the central cholinergic system by direct receptor agonists or acetylcholinesterase (AChE) inhibitors, mediates a rise in arterial pressure.

Esta dissertação estuda a linguagem do Sueste da Beira nos planos diacrónico e sincrónico. Começa por, partindo do que a tradição científica identifica, apresentar as principais questões e os principais traços definidores da referida linguagem e por fazer uma breve caracterização (apontada ao foco da dissertação) dos falares de Espanha confinantes com a mesma linguagem. Depois faz estudos descritivos dessa linguagem nas suas fases antiga – partindo de um corpus de documentos produzidos na região nos séculos XIII e XIV – e contemporânea – partindo de dados do Atlas Linguístico-Etnográfico de Portugal e da Galiza e de dados de recolha própria. Finalmente, junta os elementos apurados nas análises anteriores.