Sharif Digital Repository

Spinal load models have become an increasingly valuable tool for the evaluation of the stress placed on the spine. In order to get an accurate representation of these spinal loads, they must be compared to known tolerance values. Bone mineral content and density of the lumbar spine of 23 males and 21 females was measured using a dual energy x-ray absorptiometry. Compression tolerance values were predicted by previously published studies based upon bone mineral levels. Anthropometric measurements were recorded and related to the compression tolerance values through the use of multivariate linear regression techniques. Compression tolerance values based on the bone mineral content or density... 

Body weight is influenced by both food intake and energy expenditure. Acylated ghrelin enhances appetite, and its circulating level is suppressed by Growth Hormone. Data on the acylated ghrelin responses to exercise of different intensities in obese individuals are currently not available. This study examined the effects of an intermittent exercise protocol on acylated ghrelin levels and hunger ratings in obese people. Nine inactive male ran on the treadmill at 0900 with progressive intensities of 50, 60, 70, and 80% of VO2max for 10, 10, 5, and 2 min respectively. Blood samples were collected before the exercise at 0845 (-15 min as the resting values), after each workload (10, 23, 31, and... 

Background: Superior biomechanical performance of tapered interference screws, compared with non-tapered screws, with reference to the anterior cruciate ligament (ACL) reconstruction process, has been reported in the literature. However, the effect of tapered interference screw’s body slope on the initial stability of ACL is poorly understood. Thus, the main goal of this study was to investigate the effect of the interference screw’s body slope on the initial stability of the reconstructed ACL. Methods: Based on the best screw-bone tunnel diameter ratios in non-tapered screws, two different tapered interference screws were designed and fabricated. The diameters of both screws were equal to... 

Due to the complexity of the human spinal motion segments, the intervertebral joints are often simulated in the musculoskeletal trunk models as pivots thus allowing no translational degrees of freedom (DOFs). This work aims to investigate, for the first time, the effect of such widely used assumption on trunk muscle forces, spinal loads, kinematics, and stability during a number of static activities. To address this, the shear deformable beam elements used in our nonlinear finite element (OFE) musculoskeletal model of the trunk were either substantially stiffened in translational directions (SFE model) or replaced by hinge joints interconnected through rotational springs (HFE model). Results... 

Background: Performance indices provide quantitative measures for the quality of motion, and therefore, assist in analyzing and monitoring patients' progress. Measurement of performance indices requires costly devices, such as motion capture systems. Recent developments of sensors for game controllers, such as Microsoft Kinect, have motivated many researchers to develop affordable systems for performance measurement applicable to home and clinical care. In this work, the capability of Kinect in finding motion performance indices was assessed by analyzing intra-session and inter-session test-retest reliability. Method: Eighteen stroke patients and twelve healthy subjects participated in this... 

Objective(s): The molecular basis of “metabolically healthy obese” and “metabolically unhealthy non-obese” phenotypes is not fully understood. Our objective was to identify metabolite patterns differing in obese (metabolically healthy vs unhealthy (MHO vs MUHO)) and non-obese (metabolically healthy vs unhealthy (MHNO vs MUHNO)) individuals. Materials and Methods: This case-control study was performed on 86 subjects stratified into four groups using anthropometric and clinical measurements: MHO (21), MUHO (21), MHNO (22), and MUHNO (22). Serum metabolites were profiled using nuclear magnetic resonance (NMR). Multivariate analysis was applied to uncover discriminant metabolites, and enrichment...