Effects of walking speed and age on the muscle forces of unimpaired gait subjects

Clinical gait analysis provides great contributions to the understanding of gait disorders and also provides a mean for a more comprehensive treatment plan. However, direct measures of muscle forces are difficult to obtain in clinical settings because it generally requires invasive techniques. Techniques of musculoskeletal modeling have been used for several decades to improve the benefits of clinical gait analysis, but many of the previous studies were focused on analyzing separately the muscle forces distribution of children or adult subjects with only one condition of walking speed. For these reason, the present study aims to enhance the current literature by describing the age and speed gait effects on muscle forces during walking. We used a musculoskeletal model with 23 degrees of freedom and 92 musculotendon actuators to represent 76 muscles in the lower extremities and torso. The computed muscle control algorithm was used to estimate the muscle forces from the kinematics and to adjust the model obtained in the residual reduction algorithm. We find that hamstrings has an important peak in the mid-stance phase in the adult group but this peak disappears in the children group with the same walking speed condition. Furthermore, the rectus femoris presents an increase in the muscle force during the pre- and mid-swing in concordance with the increment in the walking speed of subjects. This behavior could be associated with the role that the rectus femoris has in the acceleration of the knee joint. Finally, we show that the soleus is the muscle that perform the major force throughout the gait cycle regardless of age and walking speed.Fil: Fliger, Carlos G.. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; ArgentinaFil: Crespo, Marcos J.. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Braidot, Ariel A.. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; ArgentinaFil: Ravera, Emiliano Pablo. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Análisis cinemático del salto en pacientes sin patologías en extremidades inferiores

El salto vertical es una habilidad relevante en el desempeño de muchos deportes de alto rendimiento, como el voleibol, básquetbol y fútbol. El gesto está basado en un conjunto de variables independientes específicas, cada una de las cuales puede afectar o favorecer en el rendimiento final. En este trabajo se realizó un análisis cinemático del salto vertical en deportistas amateurs sin antecedentes patológicos en extremidades inferiores, por medio de dos técnicas de squat jump. Para esto, se utilizó un sistema de videografía bidimensional y softwares desarrollados anteriormente en el laboratorio de biomecánica. Se evaluaron los ángulos entre segmentos, posiciones y desplazamientos de los centros de gravedad y velocidades de las articulaciones anatómicas, en cada variante del ejercicio. Los resultados obtenidos permiten caracterizar el gesto realizado y comparar las dos técnicas evaluadas. Se demostró que la técnica mejora el desempeño del salto vertical cuando se usa el balanceo de los brazos, aumentando la altura del centro de masa del cuerpo entero. El estudio demuestra ser una herramienta factible como referencias para futuros análisis del salto vertical en extremidades inferiores.Vertical jumping is a crucial ability in the performance of several sports such as volleyball, basketball and football. The standing vertical jump is based on several specific independent variables, where each can affect or improve the final performance. The main goal of this study was to examine the kinematic vertical jump in amateurs sportsmen without pathological antecedents in lower limbs, through two types of squat jump. The movement was analyzed using two-dimensional video system and the data were processed with the use of software developed in the laboratory. The angles among segments, positions and displacements of the center of mass and anatomical joints velocities were evaluated, in each variant of the exercise. The results obtained allow the characterization of the standing vertical jump performed by the subject and allow the comparison of both techniques as well. It was demonstrated that this technique improves performance of the vertical jump while using arm swing which leads to an increase in height of the body’s center of mass

Preprocesamiento alternativo de imágenes 3D de MRA

En los últimos años el avance de los sistemas de cómputo han permitido un sustancial progreso en las aplicaciones del procesamiento digital de imágenes. Este avance se refleja especialmente en el grado de mejoramiento de las imágenes de tomografía axial computada, ecografía y resonancia magnética nuclear. Una aplicación interesante del procesamiento de imágenes es la identificación del estrechamiento en los vasos. Particularmente en el registro de imágenes mediante MRA se requiere el realce de las imágenes para visualizar nítidamente vasos pequeños. En este marco, se han propuesto trabajos que usan como pre-procesamiento el máximo local medio (LMM) para aumentar la detectabilidad de vasos pequeños. A cada dato correspondiente a un voxel en el volumen original tridimensional (3- D), se aplica el LMM a una línea en el cubo centrada en el voxel de interes y se forma el juego de datos 3-D LMM. A los datos 3-D LMM se le aplica la proyección de máxima intensidad (MIP) para producir la imagen bidimensional (2-D) LMM-MIP que aumenta la detectabilidad de vasos pequeños. En este contexto se propone una modificación de los algoritmos de LMM empleando la mediana en el pre-procesamientoIII Workshop de Computación Gráfica, Imágenes y Visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI

Preprocesamiento alternativo de imágenes 3D de MRA

En los últimos años el avance de los sistemas de cómputo han permitido un sustancial progreso en las aplicaciones del procesamiento digital de imágenes. Este avance se refleja especialmente en el grado de mejoramiento de las imágenes de tomografía axial computada, ecografía y resonancia magnética nuclear. Una aplicación interesante del procesamiento de imágenes es la identificación del estrechamiento en los vasos. Particularmente en el registro de imágenes mediante MRA se requiere el realce de las imágenes para visualizar nítidamente vasos pequeños. En este marco, se han propuesto trabajos que usan como pre-procesamiento el máximo local medio (LMM) para aumentar la detectabilidad de vasos pequeños. A cada dato correspondiente a un voxel en el volumen original tridimensional (3- D), se aplica el LMM a una línea en el cubo centrada en el voxel de interes y se forma el juego de datos 3-D LMM. A los datos 3-D LMM se le aplica la proyección de máxima intensidad (MIP) para producir la imagen bidimensional (2-D) LMM-MIP que aumenta la detectabilidad de vasos pequeños. En este contexto se propone una modificación de los algoritmos de LMM empleando la mediana en el pre-procesamientoIII Workshop de Computación Gráfica, Imágenes y Visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI

Anterior Cruciate Ligament Injury: Compensation during Gait using Hamstring Muscle Activity

Previous research has shown that an increase in hamstring activation may compensate for anterior tibial transalation (ATT) in patients with anterior cruciate ligament deficient knee (ACLd); however, the effects of this compensation still remain unclear. The goals of this study were to quantify the activation of the hamstring muscles needed to compensate the ATT in ACLd knee during the complete gait cycle and to evaluate the effect of this compensation on quadriceps activation and joint contact forces. A two dimensional model of the knee was used, which included the tibiofemoral and patellofemoral joints, knee ligaments, the medial capsule and two muscles units. Simulations were conducted to determine the ATT in healthy and ACLd knee and the hamstring activation needed to correct the abnormal ATT to normal levels (100% compensation) and to 50% compensation. Then, the quadriceps activation and the joint contact forces were calculated. Results showed that 100% compensation would require hamstring and quadriceps activations larger than their maximum isometric force, and would generate an increment in the peak contact force at the tibiofemoral (115%) and patellofemoral (48%) joint with respect to the healthy knee. On the other hand, 50% compensation would require less force generated by the muscles (less than 0.85 of maximum isometric force) and smaller contact forces (peak tibiofemoral contact force increased 23% and peak patellofemoral contact force decreased 7.5% with respect to the healthy knee). Total compensation of ATT by means of increased hamstring activity is possible; however, partial compensation represents a less deleterious strategy

Evaluation of IMU ZigBee Sensors for Upper Limb Rehabilitation

This research presents a novel wireless sensor technology designed to improve post-stroke rehabilitation robotics. This new system consists in a ZigBee network, based on wearable Inertial Measurement Units (IMU) easily adaptable to patient clothing or orthotic frames, allowing kinematic measurements in continuous therapy motion all over the body segments as a Body Sensor Network (BSN). The developed system was applied to upper limb movement during repetitions of a standard trial of reaching and grasping, due to its importance in post-stroke victims daily life. The presented tool was evaluated through simultaneous capture of the movement by an optical tracking system. This allowed to contrast the elbow angle variation obtained from IMU measurement with 3D photogrammetry data, recognized as the golden standard method.Fil: Cifuentes, Carlos A.. Universidade Federal do Espírito Santo; BrasilFil: Braidot, Ariel Andrés Antonio. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Frisoli, Melisa Antonella. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Santiago, Alfonso. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; ArgentinaFil: Frizera, Anselmo. Universidade Federal do Espírito Santo; BrasilFil: Moreno, Juan. Consejo Superior de Investigaciones Científicas; Españ

Where Brain, Body and World Collide

The production cross section of electrons from semileptonic decays of beauty hadrons was measured at mid-rapidity (|y| < 0.8) in the transverse momentum range 1 < pt < 8 Gev/c with the ALICE experiment at the CERN LHC in pp collisions at a center of mass energy sqrt{s} = 7 TeV using an integrated luminosity of 2.2 nb^{-1}. Electrons from beauty hadron decays were selected based on the displacement of the decay vertex from the collision vertex. A perturbative QCD calculation agrees with the measurement within uncertainties. The data were extrapolated to the full phase space to determine the total cross section for the production of beauty quark-antiquark pairs

Fatores de personalidade e evolu??o cl?nica em pacientes transplantados de rim

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS ([email protected]) on 2015-10-28T22:00:26Z No. of bitstreams: 1 475925 - Texto Completo.pdf: 4376108 bytes, checksum: 6bf0771ea7aea9aa52f43e4e367e7bab (MD5)Made available in DSpace on 2015-10-28T22:00:26Z (GMT). No. of bitstreams: 1 475925 - Texto Completo.pdf: 4376108 bytes, checksum: 6bf0771ea7aea9aa52f43e4e367e7bab (MD5) Previous issue date: 2015-08-31Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPESConselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPqThe relationship between personality and health is frequently studied in scientific research. This study aimed to investigate the clinical/biochemical course of kidney transplant patients and its relationship with personality traits in the 3rd, 6th and 9th month after transplantation. Participants were 114 kidney transplant patients, 68 men and 46 women, with an average age of 47.72 years (SD=11.4). Personality was assessed using the Brazilian Factorial Personality Inventory (BFP). Patient charts were used to record clinical/biochemical variables over nine months following transplantation (hypertension, acute rejection, graft loss, death, creatinine and estimated glomerular filtration rate/eGFR). In addition to sociodemographic variables, information was also collected on transfusions prior to transplantation and panel reactive antibodies (HLA I and II).Two groups with personality types were differentiated by psychological characteristics (hierarchical cluster analysis): Cluster 1- average Neuroticism, high Surgency, Agreeableness and Conscientiousness, and low Openness; Cluster 2- high Neuroticism, average Surgency and Agreeableness, average Conscientiousness and low Openness. There was no statistically significant difference between the two clusters in terms of hypertension, acute infection, graft loss, death and HLA I and II panel reactive antibodies. Creatinine levels, eGFR and transfusions were associated with personality types. Cluster 1 contained significantly higher creatinine levels than Cluster 2 and these remained high on all three assessment occasions, with transfusion prior to transplantation less frequent in this group. Cluster 1 exhibited a slight decrease in average eGFR over time, with an increase observed in cluster 2. In individual analyses, Neuroticism was higher in patients with lower schooling levels (p=0.002) and exhibited a significant positive correlation with average eGFR (r=0.250; p=0.008). Agreeableness was significantly higher in men patients (p<0.001) and those without infection (p=0.050). Agreeableness also showed a significant positive correlation with average creatinine levels (r= 0.250; p= 0.007) and a negative association with eGFR (r=-0.208; p=0.027). Higher levels of Conscientiousness were observed in participants with children (p=0.026) not taking medication for depression (p=0.033), as well as a positive correlation with HLA I panel reactive antibodies (r=0.223; p=0.018). In relation to Openness, the only statistically significant difference identified was in relation to schooling, with higher average values found among participants who had completed higher education (p=0.037). The results suggest that personality traits may be associated with transplant results. Monitoring these patients over a longer period may provide a better understanding of the relationship between personality traits and clinical course during the posttransplant period.A rela??o entre personalidade e sa?de tem sido objeto de estudo frequente em pesquisas cient?ficas. Este estudo teve como objetivo principal investigar a evolu??o cl?nica/laboratorial de pacientes transplantados de rim e sua rela??o com tra?os de personalidade no 30, 60 e 90 m?s ap?s o transplante. Participaram do estudo 114 pacientes transplantados renais, 68 homens e 46 mulheres, com idade m?dia de 47,72 anos (DP=11,4). Para a avalia??o da personalidade foi utilizada a Bateria Fatorial de Personalidade (BFP). A partir dos prontu?rios, foram registradas as vari?veis cl?nicas/laboratoriais ao longo de nove meses ap?s o transplante (hipertens?o arterial (HA), rejei??o aguda, infec??o, perda do enxerto, ?bito, creatinina e taxa de filtra??o glomerular estimada/ TFGe). Al?m das vari?veis sociodemogr?ficas, coletaram-se ainda informa??es sobre as transfus?es pr?vias ao transplante e Painel de ant?genos HLA (classe I e II). Dois grupos com perfis de personalidade foram diferenciados pelas caracter?sticas psicol?gicas (an?lise de cluster hierarquizado): Cluster 1- Neuroticismo m?dio, Extrovers?o, Socializa??o e Realiza??o altos e Abertura baixo; Cluster 2- Neuroticismo alto, Extrovers?o, Socializa??o, Realiza??o m?dio e Abertura baixo. Para HA, rejei??o aguda, infec??o, perda do enxerto, ?bito e Painel de ant?genos HLA, classe I e II n?o houve diferen?a estatisticamente significativa entre os dois Clusters. Os n?veis de creatinina, TFGe e transfus?es tiveram associa??o com os perfis de personalidade. Verificou-se que o Cluster 1 concentrou n?veis de creatinina significativamente mais altos que o Cluster 2 e que se mantiveram mais elevados nos tr?s momentos de avalia??o, sendo a transfus?o pr?via ao transplante menos frequente neste grupo. No Cluster 1 ocorreu leve redu??o da m?dia de TFGe ao longo do tempo, enquanto que no Cluster 2 houve aumento. Nas an?lises individuais, Neuroticismo apresentou m?dias mais elevadas nos pacientes com menor escolaridade (p=0,002) e correla??o significativa e positiva com a m?dia de TFGe (r=0,250; p=0,008). O fator Socializa??o apresentou m?dias significativamente mais elevadas nos pacientes homens (p<0,001) e em pacientes sem infe??o (p=0,050). Al?m disto, o fator Socializa??o indicou correla??o significativa positiva com a m?dia de creatinina (r= 0,250; p= 0,007) e negativa com TFGe (r=-0,208; p=0,027). O fator Realiza??o apontou n?veis mais altos nos participantes com filhos (p=0,026) e sem uso de medica??es para depress?o (p=0,033), al?m de correla??o positiva com Reatividade contra painel de ant?genos HLA I (r=0,223; p=0,018). No fator Abertura a ?nica diferen?a estat?stica significativa identificada foi em rela??o ? escolaridade que apontou maiores m?dias nos investigados com Ensino Superior (p=0,037). Os resultados sugerem que as caracter?sticas de personalidade podem estar associadas aos resultados do transplante O acompanhamento destes pacientes durante um per?odo maior poder? levar a um melhor entendimento da rela??o entre fatores de personalidade e evolu??o cl?nica no per?odo p?s-transplante