BACKGROUND AND PURPOSE In patients with epidural lipomatosis, axial lumbar spine CT and MR images occasionally reveal a geometric, polygonal or stellar, shape of the dural sac. The purpose of this study was to define the anatomic structures responsible for this radiologic appearance. We hypothesized that meningovertebral ligaments could anchor the dura mater to the osteofibrous walls of the spi...

A local constitutive model for anisotropic granular materials is introduced and applied to isobaric (homogeneous) axial-symmetric deformation. The simplified model (in the coordinate system of the bi-axial box) involves only scalar values for hydrostatic and shear stresses, for the volumetric and shear strains as well as for the new ingredient, the anisotropy modulus. The non-linear constitutiv...

OBJECTIVE In developing countries, tibial shaft fractures are frequently stabilised using Surgical Implant Generation Network (SIGN) nails. Despite widespread use throughout the world, little is known regarding their biomechanical properties. This study aimed to compare the mechanical stiffness of the SIGN tibial nail with a standard hollow tibial nail. METHODS A fracture gap model was create...

Electroreflection and Raman spectra (in situ and ex situ) of zinc phthalocyanine (ZnPc) films (80 nm thick) have been studied. Raman spectra were resonantly and preresonantly enhanced. Both electroreflection and Raman experiments reveal the homogeneous inclusion of electrolyte anions upon oxidation of the film. The anions coordinate preferentially axial positions of the ZnPc molecule. This proc...

The energy absorbing capability is one of the most important aspects of crushing behavior of a structure subjected to axial impact. In this paper, a simple practical method is introduced to enhance the crushing behavior of this kind of structure. The axial impact of metallic energy absorbing thin-walled tubes with special shaped cross-section is simulated using LS-DYNA software. The effect of c...

A mathematical model of blood flow through an arterial vessel is presented and the wave propagation in it is studied numerically. Based on the assumption of long wavelength and small amplitude of the pressure waves, a quasi-one-dimensional (1D) differential model is adopted. It describes the non-linear fluid-wall interaction and includes wall deformation in both radial and axial directions. The...