2,684 research outputs found

    Electromyographic assessment of scapular girdle and arm muscles during exercises with fixed boundary and axial load

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    O objetivo deste estudo foi comparar a atividade eletromiográfica de músculos da cintura escapular e braço entre os exercícios wall-press 90°, wall-press 45°, bench-press e push-up, realizados com a extremidade distal do segmento fixa sobre uma superfície estável e em esforço isométrico máximo. Participaram desta pesquisa 20 voluntários do sexo masculino, sedentários e sem história de trauma ou doenças na extremidade superior. A atividade elétrica da cabeça longa do músculo bíceps braquial, da porção anterior do músculo deltóide, da porção clavicular do músculo peitoral maior e do músculo serrátil anterior foi registrada por eletromiografia de superfície. O teste modelo estatístico ANOVA e o teste post-hoc de Tukey foram utilizados para determinar diferenças entre os valores de RMS de cada músculo e em cada exercício, normalizados pela contração isométrica voluntária máxima. Os resultados do presente estudo demonstram que o músculo bíceps braquial apresentou a menor atividade eletromiográfica em comparação com os demais músculos avaliados em todos os exercícios, enquanto a porção anterior do músculo deltóide e o serrátil anterior mostraram maior atividade eletromiográfica em relação aos demais músculos nos exercícios bench-press e push-up. Esses achados demonstram que não houve semelhança na atividade eletromiográfica dos músculos avaliados durante os exercícios, porém, houve coativação muscular, visto que os exercícios ativaram todos os músculos, mesmo que em diferentes níveis. Os exercícios estudados não são indicados para ativar o músculo bíceps braquial, mas os exercícios bench-press e push-up o são para ativar a porção anterior do músculo deltóide e o serrátil anterior; o wall-press 90° e o wall-press 45° são indicados para ativar a porção anterior do músculo trapézio.The objective of this study was to compare the electromyography activity of scapular and arm muscles in the wall-press 90°, wall-press 45°, bench-press and push-up exercises, accomplished with the distal extremity of the segment on a stable surface and in maximum isometric effort. Twenty male sedentary (23±7 years), and without trauma history or diseases in the upper extremity volunteers participated in this research. The electric activity of the long head of the muscle biceps brachii, the anterior portion of the deltoid muscle, the clavicular portion of the pectoralis major and the serratus anterior muscle was registered by electromyography surface. The ANOVA and Tukey post hoc were used to determine differences between the RMS values of each muscle and in each exercise, normalized by the maximal voluntary isometric contractions. The results of the present study demonstrated that the biceps brachii muscle presented the smallest electromyographic activity in comparison to the other muscles in all exercises, while the anterior portion of the deltoid and the serratus anterior muscles presented larger electromyography activity in relation to the other muscles in the bench-press and push-up exercises. These findings demonstrate that there was not similarity in the electromyography activity of the evaluated muscles during the exercises; however, there was a muscular coactivation, since the exercises activated all muscles, even if at different levels. The studied exercises are not recommended for activation of the biceps brachii muscle; however, the bench-press and push-up exercises are recommended to activate the anterior portion of deltoid and serratus anterior muscles. Moreover, the wall-press 90° and the wall-press 45° are recommended for activation of the upper trapezius muscle

    VIH e Doença Coronária - Quando a Prevenção Secundária É Insuficiente

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    Highly active antiretroviral therapy (HAART) has created a new paradigm for human immunodeficiency virus (HIV)-infected patients, but their increased risk for coronary disease is well documented. We present the case of a 57-year-old man, co-infected with HIV-2 and hepatitis B virus, adequately controlled and with insulin-treated type 2 diabetes and dyslipidemia, who was admitted with non-ST elevation acute myocardial infarction. Coronary angiography performed on day four of hospital stay documented two-vessel disease (mid segment of the right coronary artery [RCA, 90% stenosis] and the first marginal). Two drug-eluting stents were successfully implanted. The patient was discharged under dual antiplatelet therapy (aspirin 100 mg/day and clopidogrel 75 mg/day) and standard coronary artery disease medication. He was admitted to the emergency room four hours after discharge with chest pain radiating to the left arm and inferior ST-segment elevation myocardial infarction was diagnosed. Coronary angiography was performed within one hour and documented thrombosis of both stents. Optical coherence tomography revealed good apposition of the stent in the RCA, with intrastent thrombus. Angioplasty was performed, with a good outcome. The acute stent thrombosis might be explained by the thrombotic potential of HIV infection and diabetes. There are no specific guidelines regarding HAART in secondary prevention of acute coronary syndromes. A multidisciplinary approach is essential for optimal management of these patients.info:eu-repo/semantics/publishedVersio

    Age estimation using the radiographic visibility of the periodontal ligament in lower third molars in a Portuguese population

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    Objectives: The mineralization of third molars has been used repeatedly as a method of forensic age estimation. However, this procedure is of little use beyond age 18, especially to determinate if an individual is older than 21 years of age; thus, the development of new approaches is essential. The visibility of the periodontal ligament has been suggested for this purpose. The aim of this work was to determine the usefulness of this methodology in a Portuguese population. Study Design: Periodontal ligament visibility was assessed in the lower third molars, using a sample of 487 orthopantomograms, 228 of which belonging to females and 259 to males, from a Portuguese population aged 17 to 31 years. A classification of four stages based on the visual phenomenon of disappearance of the periodontal ligament of fully mineralized third molars was used. For each stage, median, variance, minimal and maximal age were assessed. Results: The relationship between age and stage of periodontal ligament had a statistical significance for both sexes. In this population, stage 3 can be used to state that a male person is over 21 years-old; for females, another marker should be used. Conclusions: This technique can be useful for determining age over 21, particularly in males. Differences between studies are evident, suggesting that specific population standards should be used when applying this technique

    Fast left ventricle tracking in CMR images using localized anatomical affine optical flow

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    "Progress in Biomedical Optics and Imaging, vol. 16, nr. 41"In daily cardiology practice, assessment of left ventricular (LV) global function using non-invasive imaging remains central for the diagnosis and follow-up of patients with cardiovascular diseases. Despite the different methodologies currently accessible for LV segmentation in cardiac magnetic resonance (CMR) images, a fast and complete LV delineation is still limitedly available for routine use. In this study, a localized anatomically constrained affine optical flow method is proposed for fast and automatic LV tracking throughout the full cardiac cycle in short-axis CMR images. Starting from an automatically delineated LV in the end-diastolic frame, the endocardial and epicardial boundaries are propagated by estimating the motion between adjacent cardiac phases using optical flow. In order to reduce the computational burden, the motion is only estimated in an anatomical region of interest around the tracked boundaries and subsequently integrated into a local affine motion model. Such localized estimation enables to capture complex motion patterns, while still being spatially consistent. The method was validated on 45 CMR datasets taken from the 2009 MICCAI LV segmentation challenge. The proposed approach proved to be robust and efficient, with an average distance error of 2.1 mm and a correlation with reference ejection fraction of 0.98 (1.9 ± 4.5%). Moreover, it showed to be fast, taking 5 seconds for the tracking of a full 4D dataset (30 ms per image). Overall, a novel fast, robust and accurate LV tracking methodology was proposed, enabling accurate assessment of relevant global function cardiac indices, such as volumes and ejection fraction.The authors acknowledge funding support from FCT - Fundação para a Ciência e Tecnologia, Portugal, in the scope of the PhD grant SFRH/BD/93443/2013 and the project EXPL/BBB-BMD/2473/2013. D. Barbosa would also like to acknowledge the kind support of the Fundação Luso-Americana para o Desenvolvimento (FLAD), which has funded the travel costs for participation at SPIE Medical Imaging 2015.info:eu-repo/semantics/publishedVersio

    Cytotoxicity analysis of three Bacillus thuringiensis Subsp. israelensis d-Endotoxins towards insect and mammalian cells

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    Three members of the d-endotoxin group of toxins expressed by Bacillus thuringiensis subsp. israelensis, Cyt2Ba, Cry4Aa and Cry11A, were individually expressed in recombinant acrystalliferous B. thuringiensis strains for in vitro evaluation of their toxic activities against insect and mammalian cell lines. Both Cry4Aa and Cry11A toxins, activated with either trypsin or Spodoptera frugiperda gastric juice (GJ), resulted in different cleavage patterns for the activated toxins as seen by SDS-PAGE. The GJ-processed proteins were not cytotoxic to insect cell cultures. On the other hand, the combination of the trypsinactivated Cry4Aa and Cry11A toxins yielded the highest levels of cytotoxicity to all insect cells tested. The combination of activated Cyt2Ba and Cry11A also showed higher toxic activity than that of toxins activated individually. When activated Cry4Aa, Cry11A and Cyt2Ba were used simultaneously in the same assay a decrease in toxic activity was observed in all insect cells tested. No toxic effect was observed for the trypsin-activated Cry toxins in mammalian cells, but activated Cyt2Ba was toxic to human breast cancer cells (MCF-7) when tested at 20 mg/mL

    Multispecies virial expansions

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    We study the virial expansion of mixtures of countably many different types of particles. The main tool is the Lagrange–Good inversion formula, which has other applications such as counting coloured trees or studying probability generating functions in multi-type branching processes. We prove that the virial expansion converges absolutely in a domain of small densities. In addition, we establish that the virial coefficients can be expressed in terms of two-connected graphs

    Optimization Techniques for Wireless Power Transfer using Resonant Coupled Coils

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    The construction of a wireless power transfer system that guarantees an output power for a determined range is needed for manufacturing in large quantities and for the fulfillment of specifications that bring quality of service and other advantages like predicting what will be the manufacturing costs, occupied space and the overall performance, even taking into account that differences in coil construction, even with standardized production, can still not compromise the system and obtain a good performance. The challenges are the determination of work frequency, coil inductance and parasitic capacitance to know what coils should be build and how they should be build when taking into account the number of turns, height and radius of the coils and creating a model that shows the behavior of the system while distance changes. The proposed solution consists in creating mathematical models to calculate inductance, parasitic capacity and frequency of the coils and to study the behavior of the coupling coefficient, k, the mutual inductance, M, the power, or in this case, secondary voltage, V2, that arrives at the receiver, and the rate of transferred energy, RoTE, and global efficiency to predict what coils should be dimensioned and for what range the system guarantees a given output power. A prototype was built to validate the models created and simulations were made to improve prototype blocks before primary.A construção de um sistema de transferência de energia sem fios que garanta uma potência de saída para um determinado alcance é necessária para a fabricação em grandes quantidades destes dispositivos e para o atendimento de especificações que tragam qualidade de serviço e outras vantagens como prever quais serão os custos de fabricação, espaço ocupado e o desempenho geral, mesmo tendo em consideração que diferenças na construção das bobinas, mesmo com produção em série, conseguem ainda assim não comprometer o sistema e obter um bom desempenho. Os desafios são a determinação da frequência de trabalho, indutância da bobina e capacitância parasita para saber que bobinas devem ser construídas e como devem ser construídas considerando o número de espiras, altura e raio das bobinas e criando um modelo que mostre o comportamento do sistema enquanto a distância muda. A solução proposta consiste em criar modelos matemáticos para calcular a indutância, capacidade parasita e frequência das bobinas e estudar o comportamento do coeficiente de acoplamento, k, a indutância mútua, M, a potência, ou neste caso, tensão do secundário, V2, que chega ao receptor, a taxa de energia transferida, RoTE e eficiência global para prever que bobinas devem ser dimensionadas e para que alcance o sistema garante uma determinada potência de saída. Um protótipo foi construído para validar os modelos criados e foram feitas simulações para melhorar os blocos do protótipo antes do primário
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