Two and three-dimensional morphometric analysis of trabecular bone using X-ray microtomography (µCT)

INTRODUCTION: Trabecular bones have a porous microstructure and can be modeled as linear elastic solids, heterogeneous and anisotropic. In the literature, few investigations have compared the two- dimensional (2D) and three-dimensional (3D) morphometric analyses of cancellous bone. METHODS: In this investigation eighteen cylindrical samples of cancellous bone (10 mm of diameter and 20 mm of height) were obtained from six bovine head femurs, with similar values for the weight and age, of the same race and gender. The samples were harvested and freezed at - 20 °C before carrying out the microCT analysis. The CT-Analyzer software was used to measure in three directions (superior-inferior, lateral-medial and anterior-posterior) parameters such as trabecular thickness, trabecular separation, trabecular number and the eigenvalues of the fabric tensor (M). RESULTS: The Comparison of 2D and 3D analyses for the parameters: 2D (plate model) trabecular thickness, trabecular separation and trabecular number were statistically different (p = 0) showing that measurements are not similar to the 3D ones. However, 2D (rod model) trabecular thickness and 3D trabecular thickness measurements presented no significant difference (p = 0.26). The eigenvalues show that the bovine trabecular microstructure has a tendency to transverserly isotropic symmetry. DISCUSSION: The method proved to be quite interesting for the characterization of the bone structure through 3D measurements of trabecular bone morphometric parameters in the three possible directions of loading. The results show that x-ray microtomography (∝CT) is a technique of great potential for characterization and generating bone quality parameters for the diagnosis of bone metabolism diseases.

Construção de um cicloergômetro de baixo custo para membros superiores e inferiores / Construction of low cost ergometer for upper and lower limbs

Este artigo descreve uma bicicleta ergométrica construída e adaptada com um sistema de manípulos capazes de realizar o exercício rotativo simultâneo dos membros superiores e inferiores. O equipamento foi calibrado após adaptação de um torquímetro de alumínio, e as medidas foram registradas por um sistema para medição de torque em eixos rotativos por meio de telemetria. Foi realizada a calibração dinâmica dos manípulos e dos pedais, e os dados foram registrados a cada seis ciclos de carga pré-determinados pelo aperto de uma fita de couro geradora de resistência ao movimento. Foram determinados dois pontos de fixação da fita de couro na estrutura da bicicleta para obter um maior número de carga, esta exercida de forma gradativa durante a realização de exercícios no equipamento. Através dos resultados das calibrações visualizadas pela ponte de telemetria, observou-se que no 1º ponto de fixação da fita de couro, tanto na calibração dos manípulos como na dos pedais, obteve-se a carga máxima de 6mv/v. No 2º ponto de fixação da fita de couro, na calibração dos manípulos, foi registrada a carga máxima de 14 mv/v e, na calibração dos pedais, a carga máxima foi de 16 mv/v. A calibração dinâmica mostrou que o equipamento possui recursos de medidas de carga e que, provavelmente, poderá ser utilizado na reabilitação de pacientes com patologias diversas. Por fim, conclui-se que o equipamento é de baixo custo e sem similar no mercado nacional, podendo ser útil para a realização de testes de esforços físicos.

This article describes an exercise bike built and fitted with a system of levers capable of performing the exercise simultaneously rotating the upper and lower limbs. The equipment was manufactured and calibrated with a aluminum torque wrench, and the measurements were recorded by a system for measuring torque in rotating shafts by telemetry. We performed dynamic calibration of the handles and pedals, and the data were recorded every 6 load cycles predetermined by tightening a leather strap generating resistance movement. Two points of attachment of leather strap structure of the bicycle was determined to obtain a greater number of loads, which was gradually exerted during the exercises. The results of calibrations by telemetry showed that the 1st point of attachment of leather tape, both for calibration of the handles and the pedals obtained the maximum load of 6 mv / v. In the 2nd point of the leather strap, the maximum load of 14 mv / v was found to calibrate the handles and 16 mv / v to calibrate the pedals. Dynamic calibration showed that the equipment is suitable for load measurements and probably could be used in the rehabilitation of patients with different pathologies. Finally, we concluded that the equipment is inexpensive and unique in the market and is useful for testing of physical efforts.

Biocompatibilidade do revestimento de nitreto de titânio (TiN): um estudo preliminar / Biocompatibility of nitride titanium revetment: a preliminary study

Com o objetivo de analisar o comportamento à biocorrosão do revestimento de TiN, no presente trabalho foram ensaiadas amostras de aço inoxidável austeníaco (AISI316L) e aço carbono comum (1015), com e sem revestimento. As análises foram feitas a partir de curvas potenciodinâmicas realizadas em meio fisiológico com adição de 10 por cento de soro bovino. As amostras revestidas apresentaram uma menor taxa de corrosão com relação às suas respectivas sem revestimento. O melhor desempenho foi encontrado nas amostras de aço 316L revestidas com TiN.

ABSTRACT - ln order to analise TiN coating biocorrosion performance, in the present work austenitic stainless steel (AIS! 3 l 6L) and carbon steel (SAE 1O15) sample with and without coating have been examined. If was seem smaller corrosion rates for coated samples compared to the uncoated samples. The best performance was find in the AIS! 3 l 6L stainless steel TiN coated samples. Potentiodynamic polarization tests using in fisiological medi um with 10% bovine serum adition were done

Avaliaçäo da toxicidade sistêmica da poliuretana derivada de óleo de mamona: resultados preliminares / Evaluation of systemic toxicity of polyurethane derivade castor-oil plant: preliminary results

Seguindo normatizações internacionais (ASTM), a avaliação toxicológica de um material polimérico derivado de óleo de mamona está sendo feita através da injeção sistêmica em camundongos albinos. Posteriormente, será feita a averiguação histopatológica de rins, fígado, baço e pulmões. Os sinais clínicos apresentados pelos animais após a injeção não revelaram aspectos de toxicidade

Abstract - The toxicological evaluation of a polymeric material from castor oil is being carried out by systemic injection in albino mice and by a subsequent histopathological analysis of their kidneys, liver, spleen and lungs. The animais have not developed clinicai signs of toxicity after the injection. Histopathological analysis of their organs were not concluded yet