Spinal Biomechanics
Mojtaba Shahab; Behzad Seyfi; Nasser Fatouraee; Amir Saeid Seddighi
Volume 9, Issue 1 , April 2015, , Pages 1-15
Abstract
Spinal deformities are generally associated with lumbar and cervical chronic pain and additionally they disturb the health. In these deformities, lumbar spinal curvature undergone changes in three dimensional space and in most cases, they cause reduction of lung capacities, breathing problems and negative ...
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Spinal deformities are generally associated with lumbar and cervical chronic pain and additionally they disturb the health. In these deformities, lumbar spinal curvature undergone changes in three dimensional space and in most cases, they cause reduction of lung capacities, breathing problems and negative effects on cardiovascular system. In critical deformity cases, in order to correct the deformity and prevent its progression, surgeons determine to perform posterior spinal fusion. As a result, they need to extract some important clinical parameters of spine such as Cobb angle, sagittal and coronal balance, spinal curvature, vertebraes angles and their rotations. In this study, edited tomographic images in MIMICS, were used to prepare a three dimensional model of the spine. Then by using curve fitting techniques and different clustering methods such as self-organization nueral network, k-means and hierarchical method, vertebras were separated and important geometrical data such as curvature of the spine and vertebras angle were obtained. In addition, through implementation of certain algorithms, other clinical features of each vertebra, including minimum and maximum height, length and width of the vertebral body and the relative displacement of vertebras were calculated automatically. In order to validate the proposed methods, measures and angles; derived values obtained automatically at each stage, were again calculated by a radiologist and a spine surgeon who was unaware of the goals of the research. Automatic values were verified by being compared with these manual results. In conclusion the reliability, accuracy and performance of the proposed automatic algorithms were demonstrated.
Biomimetics
Behzad Seyfi; Hosein Mansourinejad; Bahman Vahidi; Nasser Fatouraee
Volume 6, Issue 3 , June 2012, , Pages 169-175
Abstract
Peristaltic flow is one of the important mechanisms of fluid transmission. In addition to the divers engineering applications, this mechanism plays an important role in biological organs such as digestion system and urine excretion. In this paper, urine bolus transportation in ureter has been investigated ...
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Peristaltic flow is one of the important mechanisms of fluid transmission. In addition to the divers engineering applications, this mechanism plays an important role in biological organs such as digestion system and urine excretion. In this paper, urine bolus transportation in ureter has been investigated experimentally using a peristaltic flow simulator apparatus. Some of the features of this apparatus worth mentioning are its ability to use it to investigate the influence of some important parameters in peristaltic flow, such as the effect of pressure difference between the kidney and the bladder on the quantity of discharge and reflux rates, effect of the mean velocity of bolus transport on discharge rate, existence of fluid film and its effect on bolus discharge rate, and effect of fluid bolus length on reflux rate. Then we compare the obtained results with the similar theoretical studies. It was observed that an increase in the pressure difference between inlet and outlet decreases the ratio of reflux to initial volume of the bolus, and it increases the discharge rate. Moreover, the quantities of reflux and discharge rate decrease by decreasing the bolus transport velocity. It was also observed that the thickness of the fluid film has an inverse relation with respect to the discharge rate and with increasing the bolus length reflux is increasing.
