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In recent years the use of artificial neural networks for classification and analysis of kinematic and kinetic characteristics of human locomotion has greatly increased. This happens in an attempt to overcome the limitations of traditional dynamic analysis and to find new clinical indicators for interpreting quick and objectively the large amount of information obtained in a gait lab. One of the most widely used neural networks for human gait analysis is the self-organizing or Kohonen map, based on unsupervised learning without prior definition of the formed natural groups. Among the advantages of using this type of neural network is the data dimensionality reduction, with minimal loss of information content, and the grouping of them in function of their similarities. Taking into account this, in this work an application case of a Kohonen map for clustering of locomotion kinetic characteristics in normal and Parkinson's disease individuals is presented. The results indicate that the groups identified by the map are consistent with the classification carried out by experts in function of traditional gait dynamic analysis, showing the potential of this technique for distinguishing between a population of individuals with normal gait and with gait disorders of different etiology.

Nos últimos anos, tem aumentado significativamente o uso de redes neurais artificiais para a classificação e análise cinemática e cinética da marcha humana, em uma tentativa de superar as limitações da análise dinâmica tradicional e de encontrar novos indicadores clínicos para interpretar, de forma rápida e objetiva, a grande quantidade de informação obtida em laboratórios de marcha humana. Uma das redes neurais mais utilizadas para análise de marcha é o mapa de Kohonen ou mapa auto-organizado, baseado em aprendizado não supervisionado, sem uma definição prévia de grupos naturais que se formam. O uso deste tipo de rede neural tem mostrado benefícios significativos associados com a redução da dimensionalidade dos dados com mínima perda de conteúdo de informação e com o agrupamento de dados de acordo com suas semelhanças. Neste contexto, este trabalho apresenta um caso de aplicação de um mapa de Kohonen como classificador das características cinéticas da locomoção em indivíduos normais e com doença de Parkinson. Os resultados indicam que os grupos identificados no mapa são consistentes com a classificação feita por especialistas com base em análise dinâmica tradicional, que mostra o potencial desta técnica para diferenciar populações de indivíduos com marcha normal e de indivíduos com distúrbios da marcha de etiologia diferente.

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OBJECTIVE: Many disorders produce similar or overlapping patterns of bone marrow edema in the ankle. Bone marrow edema may present in a few hindfoot bones simultaneously or in a single bone. The purpose of this pictorial essay is to provide guidelines based on clinical history and specific MRI patterns and locations to accurately identify the cause of ankle bone marrow edema. We will first focus on bone marrow edema in general disease categories involving multiple bones, such as reactive processes, trauma, neuroarthropathy, and arthritides. A discussion of bone marrow edema in individual bones of the ankle and hindfoot including the tibia, fibula, talus, and calcaneus will follow. Helpful hints for arriving at the correct diagnosis will be provided in each section. CONCLUSION: After review of this article, radiologists should be able to use their knowledge of clinical history and specific MRI patterns and locations to accurately distinguish between the various causes of bone marrow edema in the ankle and hindfoot.

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Within the framework of multibody dynamics, a 3D large scale neuromusculoskeletal model of the human body is presented. To characterize the dynamics of skeletal muscle, a phenomenological model of energy expenditure was developed for estimating energy consumption during normal locomotion. Such model is able for predicting thermal and mechanical energy liberation under submaximal activation, muscle fiber type, and varying contractile conditions, typically observed in human motion. Future formulations of the indeterminate biomechanical problem, solved through the physiological criteria of minimization of metabolical cost of transport during gait, should consider the role of muscle groups in coordinating multijoint motion. Such an approach is presented in part II of the paper.

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A phenomenological model of muscle energy expenditure developed in part I of the paper, is utilized as a physiological cost function to estimate the muscle forces during normal locomotion. The model takes into account muscular behaviors typically observed during human gait, such as submaximal activation, variable muscular contraction conditions and muscular fiber type. The solution of the indeterminate biomechanical problem is obtained by integrating multibody dynamics and the global static optimization technique that considers the whole motion. The results for an application case indicate the important role of muscle groups in coordinating multijoint motion with the objective of minimizing metabolic costs of transport during locomotion.

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La ateroscleroris es un proceso multifactorial de gran complejidad cuyo origen es aún desconnocido. Sin embargo, eventos característicos de su patogénesis dan evidencias de una disminuición de la densidad de carga eléctrica exnibida normalmente por el glicocáliz de los elementos parietales y sanguíneos implicados en este proceso. Las investigaciones más recientes indican que el espesor del glicocáliz endotelial es función no sólo de sus moléculas polianiónicas superficiales, sino tambíén de la composición del fluido sanguíneo. Teniendo en cuenta esta dependencia respecto de la composicón de la sangre, el objetivo de este trabajo fue investigar la influencia de la concentración electrolítica y del pH plasmáticos sobre las propiedades electrocinéticas en la interfase pared arterial - fluido sanguíneo. Para lograr esto se evaluó experimentalmente utilizando segmentos aórticos porcinos, el efecto electrocinético que ejerce sobre el endotelio arterial, el flujo de soluciones de contenido iónico y pH variables. Los resultados indicaron que el aumento del contenido iónico normal del plasma podría afectar las propriedades eléctricas de aquellos elementos, favoreciendo su acercamiento. Así también, el decremento del valor del pH fisiológico reduciría la proporción de molécular polianiónicas contenidas en el glicocáliz de dichos elementos, disminuyendo la repulsión electrostática entre ellos. De esta forma, el desarrollo aterogénico asociado con un aumento de la captación de componentes de la sangre, podría estar relacionado con una alteración de las propiedades electrocinéticas de los elementos parietales y sanguíneos involucrados, provocada por cambios de pH o concentración electrolítica plasmática

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