Hot ring rolling is a highly nonlinear, unsteady-state and asymmetry process which is affected by many parameters. The friction coefficient between the ring ,the driver roll and the idle roll is one of the problems, which has significant effect on the quality of final product. In this study, the effect of these two parameters on hot ring rolling was investigated based on a 3D coupled-thermo mec...

Background: The purpose of this prospective study was to determine the accuracy of pedicular screw insertion withoutthe use of fluoroscopy.Methods: This study was conducted on patients with spinal diseases in need of pedicular screw fixation and fusion.The included patients suffered from such conditions as vertebral fracture, spinal stenosis, kyphosis, tumor, and pelvicf...

Introduction Pedicle screws are commonly used in posterior internal fixation systems to stabilise the spine for fusion procedures. Rigid fixation systems place high requirements on the load-carrying capacity at the screw-bone interface. Poor bone quality decreases the integrity of this interface, increasing screw micromotion and consequently reducing screw stability and possibly fusion success....

background and objectives: in many studies, chronic diseases are associated with incidence of driving accident. the main objective of the present study is investigation the effect of physical and mental disorders status of bus drivers on the occurrence of crashes. materials and methods: this research is a cross-sectional and descriptive-analytical study that was performed on 665 bus drivers' pu...

background and objectives: in many studies, chronic diseases are associated with incidence of driving accident. the main objective of the present study is investigation the effect of physical and mental disorders status of bus drivers on the occurrence of crashes. materials and methods: this research is a cross-sectional and descriptive-analytical study that was performed on 665 bus drivers' pu...

PURPOSE To biomechanically evaluate single screw and varying 2 screw fixations for an unstable slipped capital femoral epiphysis (SCFE) model using physiologically relevant loading. STUDY DESIGN In vitro biomechanical study. METHODS Twenty-four immature porcine proximal femurs were prepared to simulate a mild-to-moderate unstable SCFE. The femurs were randomized into 4 fixation groups: sing...

Expansive pedicle screws significantly improve fixation strength in osteoporotic spines. However, the previous literature does not adequately address the effects of the number of lengthwise slits and the extent of screw expansion on the strength of the bone/screw interface when expansive screws are used with or without cement augmentation. Herein, four designs for expansive pedicle screws with ...