12 resultados para THUMB CONFORMATION TRANSITIONS
em Instituto Politécnico do Porto, Portugal
Resumo:
Objetivo: avaliar as modificações ocorridas no âmbito da sequência de ativação o da sinergia extensora do MS e na sua influência sobre a capacidade de placing do polegar face à aplicação de um programa de intervenção em fisioterapia. Pretendeu-se também verificar as repercussões ao nível da participação dos indivíduos nas AVD`s. Metodologia: esta série de estudos de casos foi constituída por dois indivíduos com modificações nas componentes neuromotoras de movimento após AVE predominantes no MS. A avaliação dois indivíduos foi realizada em dois momentos PRE e POST separados por um período de intervenção de cerca de quinze semanas. Em cada momento de avaliação foi aplicada a F-MAMR, foi recolhido sinal electromiográfico dos músculos GD, DP, TLONG, TLAT e ABDPOL durante o movimento de alcance e usaram-se seis itens da CIF selecionadas de acordo com as necessidades sentidas. No momento PRE aplicou-se a MMSE para detetar défices cognitivos que interferissem com o processo de avaliação e de intervenção. O programa de intervenção foi individualizado e devidamente ajustado aos indivíduos, procurando que estes mantivessem um papel ativo durante a reabilitação. Esta foi realizada com a frequência de três vezes por semana e cada sessão teve cerca de quarenta e cinco minutos de trabalho ativo. Resultados: encontraram-se modificações na sequência de ativação muscular nos dois indivíduos e entre os indivíduos nos dois momentos de avaliação, nomeadamente no tempo de ativação muscular. O ABDPOL modificou o tempo em que iniciou atividade muscular e passou a recrutar atividade quase simultaneamente ao início do movimento da mão, verificando-se uma influência positiva da sinergia extensora do MS na capacidade de placing do polegar. Verificaram-se resultados positivos no estado sensório-motor do MS e na capacidade do indivíduo em participar em diversas AVD`s selecionadas de acordo com as necessidades. Conclusão: este estudo parece apontar para uma influência positiva nas modificações do nível de atividade da sinergia extensora do MS e na influência desta sobre a capacidade de placing do polegar durante o movimento de alcance, face a um programa de intervenção. Este estudo parece apontar também para uma influência positiva sobre a capacidade do indivíduo em participar em AVD`s selecionadas para a avaliação de acordo com necessidades sentidas.
Resumo:
Imidazolidin-4-ones are commonly employed as skeletal modifications in bioactive oligopeptides, either as proline surrogates or for protection of the N-terminal amino acid against aminopeptidase-catalysed hydrolysis . We have been working on the synthesis of imidazolidin-4-ones of the antimalarial primaquine , through acylation of primaquine with an α-amino acid and subsequent reaction of the resulting α-aminoamide with a ketone or aldehyde. Thus, when using racemic primaquine, an optically pure chiral α-amino acid and an aldehyde as starting materials, four imidazolidin-4-one diastereomers are to be expected (Scheme 1). However, we have recently observed that imidazolidin-4-one synthesis was stereoselective when 2-carboxybenzaldehyde (2CBA)* was used, as only two diastereomers were produced2. Computational studies have shown that the imine formed prior to ring closure had, for structures derived from 2CBA, a quasi-cyclic rigid structure2. This rigid conformation is stabilized by an intramolecular hydrogen bond involving the C=O oxygen atom of the 2-carboxyl substituent in 2CBA and the N-H group of the α-amino amide moiety2. These findings led us to postulate that the 2-carbonyl substituent in the benzaldehyde moiety was the key for the stereoselective synthesis of the imidazolidin-4-ones2.
Resumo:
A Síndrome do Canal Cárpico (SCC) é a neuropatia compressiva mais comum do membro superior, causada pela compressão direta sobre o nervo mediano no interior do canal cárpico.Os resultados deste estudo mostram em cada um dos grupos, após a intervenção, uma melhoria estatisticamente significativa da sintomatologia no G-AFN (p=0,02) e no GTRN/ EAA (p=0,004) e uma melhoria estatisticamente significativa do estado funcional no G-AFN (p=0,022). Verificamos também em cada um dos grupos, após a intervenção, uma melhoria estatisticamente significativa na “Força de preensão” (p=0,005), na “Pinça polegar/dedo indicador” (p=0,021), na “Pinça polegar/dedo médio” (p=0,026) e “Pinça polegar/dedo anular” (p=0,026) no G-AFN, e uma melhoria estatisticamente significativa na “Pinça polegar/indicador” (p=0,016), na “Pinça polegar/dedo médio” (p=0,035), na “Pinça polegar/dedo anular” (p=0,010), na “Pinça trípode” (p=0,005) e na “Pinça lateral” (p=0,051) no G-TRN/EAA. Após a intervenção, não verificamos diferenças estatisticamente significativas nos valores das escalas de gravidade de sintomas (p=0,853) e de estado funcional (p=0,148) entre os grupos, mas diferenças estatisticamente significativas nos valores dos testes neurofisiológicos (p=0,047) e força de preensão da mão (p=0,005). Do estudo, concluímos que a utilização da intervenção articular/fascial/neural (AFN) e a intervenção com tala de repouso noturna e exercícios de auto alongamento (TRN/EAA), beneficia os indivíduos com SCC não severa, como nos casos incipientes, ligeiros ou moderados. Os indivíduos com esta condição clínica apresentam sintomatologia caraterística de dor, parestesia, especialmente noturna e disfunção muscular da mão. Tais manifestações originam perda funcional com implicações nas áreas de desempenho ocupacional, nomeadamente, nas atividades da vida diária, produtivas e de lazer. O tratamento conservador na SCC não severa, como nos casos incipientes, ligeiros e moderados, apesar de controverso, é recomendado. O tema suscita o nosso interesse, razão pela qual nos propomos realizar um estudo experimental em indivíduos com o diagnóstico clínico de SCC não severa e aplicar num grupo a intervenção articular, fascial e neural (AFN) e noutro grupo a intervenção com tala de repouso noturna e exercícios de auto alongamento (TRN/EAA). O estudo tem como principais objetivos, por um lado, verificar o impacto das intervenções em cada um dos grupos e, por outro lado, comparar o seu impacto entre os grupos, no que respeita à gravidade de sintomas, ao estado funcional, à força de preensão da mão e força de pinças finas. Fomos também comparar os resultados dos testes neurofisiológicos (Velocidade de Condução Motora) antes e depois da intervenção AFN e da intervenção com TRN/EAA, e averiguar o seu impacto nos valores da latência motora distal e da velocidade de condução sensitiva, entre os grupos. Identificamos também quais as variáveis sócio demográficas e as que caraterizam a patologia que estão relacionadas com o problema em estudo e com os valores obtidos com as escalas do Boston Carpal Tunnel Questionnaire (BCTQ), no grupo articular, fascial e neural (G-AFN) e no grupo com tala de repouso noturna e exercícios de auto alongamento (G-TRN/EAA). Para a concretização do estudo, recorremos a uma amostra de 23 indivíduos de ambos os sexos do Hospital Curry Cabral, Empresa Pública Empresarial -Centro Hospitalar de Lisboa Central (HCC, EPE -CHLC).
Resumo:
O principal objectivo da animação de personagens virtuais é o de contar uma história através da utilização de personagens virtuais emocionalmente expressivos. Os personagens têm personalidades distintas, e transmitem as suas emoções e processos de pensamento através dos seus comportamentos (comunicação não verbal). As suas acções muitas das vezes constituem a geração de movimentos corporais complexos. Existem diversas questões a considerar quando se anima uma entidade complexa, tais como, a posição das zonas móveis e as suas velocidades. Os personagens virtuais são um exemplo de entidades complexas e estão entre os elementos mais utilizados em animação computacional. O foco desta dissertação consistiu na criação de uma proposta de sistema de animação de personagens virtuais, cujos movimentos e expressões faciais são capazes de transmitir emoções e estados de espírito. Os movimentos primários, ou seja os movimentos que definem o comportamento dos personagens, são provenientes da captura de movimentos humanos (Motion Capture). As animações secundárias, tais como as expressões faciais, são criadas em Autodesk Maya recorrendo à técnica BlendShapes. Os dados obtidos pela captura de movimentos, são organizados numa biblioteca de comportamentos através de um grafo de movimentos, conhecido por Move Tree. Esta estrutura permite o controlo em tempo real dos personagens através da gestão do estado dos personagens. O sistema possibilita também a transição eficaz entre movimentos semelhantes e entre diferentes velocidades de locomoção, minimizando o efeito de arrastamento de pés conhecido como footskate. Torna-se assim possível definir um trajecto que o personagem poderá seguir com movimentos suaves. Estão também disponíveis os resultados obtidos nas sessões de avaliação realizadas, que visaram a determinação da qualidade das transições entre animações. Propõem-se ainda o melhoramento do sistema através da implementação da construção automática do grafo de movimentos.
Resumo:
In this work, tin selenide thin films (SnSex) were grown on soda lime glass substrates by selenization of dc magnetron sputtered Sn metallic precursors. Selenization was performed at maximum temperatures in the range 300 °C to 570 °C. The thickness and the composition of the films were analysed using step profilometry and energy dispersive spectroscopy, respectively. The films were structurally and optically investigated by X-ray diffraction, Raman spectroscopy and optical transmittance and reflectance measurements. X-Ray diffraction patterns suggest that for temperatures between 300 °C and 470 °C, the films are composed of the hexagonal-SnSe2 phase. By increasing the temperature, the films selenized at maximum temperatures of 530 °C and 570 °C show orthorhombic-SnSe as the dominant phase with a preferential crystal orientation along the (400) crystallographic plane. Raman scattering analysis allowed the assignment of peaks at 119 cm−1 and 185 cm−1 to the hexagonal-SnSe2 phase and those at 108 cm−1, 130 cm−1 and 150 cm−1 to the orthorhombic-SnSe phase. All samples presented traces of condensed amorphous Se with a characteristic Raman peak located at 255 cm−1. From optical measurements, the estimated band gap energies for hexagonal-SnSe2 were close to 0.9 eV and 1.7 eV for indirect forbidden and direct transitions, respectively. The samples with the dominant orthorhombic-SnSe phase presented estimated band gap energies of 0.95 eV and 1.15 eV for indirect allowed and direct allowed transitions, respectively.
Resumo:
The present study aimed to develop a pre-endothelialized chitosan (CH) porous hollowed scaffold for application in spinal cord regenerative therapies. CH conduits with different degrees of acetylation (DA; 4% and 15%) were prepared, characterized (microstructure, porosity and water uptake) and functionalized with a recombinant fragment of human fibronectin (rhFNIII7–10). Immobilized rhFNIII7–10 was characterized in terms of amount (125I-radiolabelling), exposure of cell-binding domains (immunofluorescence) and ability to mediate endothelial cell (EC) adhesion and cytoskeletal rearrangement. Functionalized conduits revealed a linear increase in immobilized rhFNIII7–10 with rhFNIII7–10 concentration, and, for the same concentration, higher amounts of rhFNIII7–10 on DA 4% compared with DA 15%. Moreover, rhFNIII7–10 concentrations as low as 5 and 20 lgml 1 in the coupling reaction were shown to provide DA 4% and 15% scaffolds, respectively, with levels of exposed cell-binding domains exceeding those observed on the control (DA 4% scaffolds incubated in a 20 lgml 1 human fibronectin solution). These grafting conditions proved to be effective in mediating EC adhesion/cytoskeletal organization on CH with DA 4% and 15%, without affecting the endothelial angiogenic potential. rhFNIII7–10 grafting to CH could be a strategy of particular interest in tissue engineering applications requiring the use of endothelialized porous matrices with tunable degradation rates.
Resumo:
In this work, we investigated structural, morphological, electrical, and optical properties from a set of Cu2ZnSnS4 thin films grown by sulfurization of metallic precursors deposited on soda lime glass substrates coated with or without molybdenum. X-ray diffraction and Raman spectroscopy measurements revealed the formation of single-phase Cu2ZnSnS4 thin films. A good crystallinity and grain compactness of the film was found by scanning electron microscopy. The grown films are poor in copper and rich in zinc, which is a composition close to that of the Cu2ZnSnS4 solar cells with best reported efficiency. Electrical conductivity and Hall effect measurements showed a high doping level and a strong compensation. The temperature dependence of the free hole concentration showed that the films are nondegenerate. Photoluminescence spectroscopy showed an asymmetric broadband emission. The experimental behavior with increasing excitation power or temperature cannot be explained by donor-acceptor pair transitions. A model of radiative recombination of an electron with a hole bound to an acceptor level, broadened by potential fluctuations of the valence-band edge, was proposed. An ionization energy for the acceptor level in the range 29–40 meV was estimated, and a value of 172 ±2 meV was obtained for the potential fluctuation in the valence-band edge.
Resumo:
Cu2ZnSnS4 is a promising semiconductor to be used as absorber in thin film solar cells. In this work, we investigated optical and structural properties of Cu2ZnSnS4 thin films grown by sulphurization of metallic precursors deposited on soda lime glass substrates. The crystalline phases were studied by X-ray diffraction measurements showing the presence of only the Cu2ZnSnS4 phase. The studied films were copper poor and zinc rich as shown by inductively coupled plasma mass spectroscopy. Scanning electron microscopy revealed a good crystallinity and compactness. An absorption coefficient varying between 3 and 4×104cm−1 was measured in the energy range between 1.75 and 3.5 eV. The band gap energy was estimated in 1.51 eV. Photoluminescence spectroscopy showed an asymmetric broad band emission. The dependence of this emission on the excitation power and temperature was investigated and compared to the predictions of the donor-acceptor-type transitions and radiative recombinations in the model of potential fluctuations. Experimental evidence was found to ascribe the observed emission to radiative transitions involving tail states created by potential fluctuations.
Resumo:
A large part of power dissipation in a system is generated by I/O devices. Increasingly these devices provide power saving mechanisms, inter alia to enhance battery life. While I/O device scheduling has been studied in the past for realtime systems, the use of energy resources by these scheduling algorithms may be improved. These approaches are crafted considering a very large overhead of device transitions. Technology enhancements have allowed the hardware vendors to reduce the device transition overhead and energy consumption. We propose an intra-task device scheduling algorithm for real time systems that allows to shut-down devices while ensuring system schedulability. Our results show an energy gain of up to 90% when compared to the techniques proposed in the state-of-the-art.
Resumo:
Embedded real-time systems often have to support the embedding system in very different and changing application scenarios. An aircraft taxiing, taking off and in cruise flight is one example. The different application scenarios are reflected in the software structure with a changing task set and thus different operational modes. At the same time there is a strong push for integrating previously isolated functionalities in single-chip multicore processors. On such multicores the behavior of the system during a mode change, when the systems transitions from one mode to another, is complex but crucial to get right. In the past we have investigated mode change in multiprocessor systems where a mode change requires a complete change of task set. Now, we present the first analysis which considers mode changes in multicore systems, which use global EDF to schedule a set of mode independent (MI) and mode specific (MS) tasks. In such systems, only the set of MS tasks has to be replaced during mode changes, without jeopardizing the schedulability of the MI tasks. Of prime concern is that the mode change is safe and efficient: i.e. the mode change needs to be performed in a predefined time window and no deadlines may be missed as a function of the mode change.
Resumo:
The interest for environmental fate assessment of chiral pharmaceuticals is increasing and enantioselective analytical methods are mandatory. This study presents an enantioselective analytical method for the quantification of seven pairs of enantiomers of pharmaceuticals and a pair of a metabolite. The selected chiral pharmaceuticals belong to three different therapeutic classes, namely selective serotonin reuptake inhibitors (venlafaxine, fluoxetine and its metabolite norfluoxetine), beta-blockers (alprenolol, bisoprolol, metoprolol, propranolol) and a beta2-adrenergic agonist (salbutamol). The analytical method was based on solid phase extraction followed by liquid chromatography tandem mass spectrometry with a triple quadrupole analyser. Briefly, Oasis® MCX cartridges were used to preconcentrate 250 mL of water samples and the reconstituted extracts were analysed with a Chirobiotic™ V under reversed mode. The effluent of a laboratory-scale aerobic granular sludge sequencing batch reactor (AGS-SBR) was used to validate the method. Linearity (r2 > 0.99), selectivity and sensitivity were achieved in the range of 20–400 ng L−1 for all enantiomers, except for norfluoxetine enantiomers which range covered 30–400 ng L−1. The method detection limits were between 0.65 and 11.5 ng L−1 and the method quantification limits were between 1.98 and 19.7 ng L−1. The identity of all enantiomers was confirmed using two MS/MS transitions and its ion ratios, according to European Commission Decision 2002/657/EC. This method was successfully applied to evaluate effluents of wastewater treatment plants (WWTP) in Portugal. Venlafaxine and fluoxetine were quantified as non-racemic mixtures (enantiomeric fraction ≠ 0.5). The enantioselective validated method was able to monitor chiral pharmaceuticals in WWTP effluents and has potential to assess the enantioselective biodegradation in bioreactors. Further application in environmental matrices as surface and estuarine waters can be exploited.
Resumo:
Activity rhythms in animal groups arise both from external changes in the environment, as well as from internal group dynamics. These cycles are reminiscent of physical and chemical systems with quasiperiodic and even chaotic behavior resulting from “autocatalytic” mechanisms. We use nonlinear differential equations to model how the coupling between the self-excitatory interactions of individuals and external forcing can produce four different types of activity rhythms: quasiperiodic, chaotic, phase locked, and displaying over or under shooting. At the transition between quasiperiodic and chaotic regimes, activity cycles are asymmetrical, with rapid activity increases and slower decreases and a phase shift between external forcing and activity. We find similar activity patterns in ant colonies in response to varying temperature during the day. Thus foraging ants operate in a region of quasiperiodicity close to a cascade of transitions leading to chaos. The model suggests that a wide range of temporal structures and irregularities seen in the activity of animal and human groups might be accounted for by the coupling between collectively generated internal clocks and external forcings.