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Finite element models of an isolated vertebral body cannot accurately predict compressive strength of the spinal column because, in life, compressive load is variably distributed across the vertebral body and neural arch. The purpose of this study was to develop and validate a patient-specific finite element model of a functional spinal unit, and then use the model to predict vertebral strength from medical images. A total of 16 cadaveric functional spinal units were scanned and then tested mechanically in bending and compression to generate a vertebral wedge fracture. Before testing, an image processing and finite element analysis framework (SpineVox-Pro), developed previously in MATLAB using ANSYS APDL, was used to generate a subject-specific finite element model with eight-node hexahedral elements. Transversely isotropic linear-elastic material properties were assigned to vertebrae, and simple homogeneous linear-elastic properties were assigned to the intervertebral disc. Forward bending loading conditions were applied to simulate manual handling. Results showed that vertebral strengths measured by experiment were positively correlated with strengths predicted by the functional spinal unit finite element model with von Mises or Drucker–Prager failure criteria (R2= 0.80–0.87), with areal bone mineral density measured by dual-energy X-ray absorptiometry (R2= 0.54) and with volumetric bone mineral density from quantitative computed tomography (R2= 0.79). Large-displacement non-linear analyses on all specimens did not improve predictions. We conclude that subject-specific finite element models of a functional spinal unit have potential to estimate the vertebral strength better than bone mineral density alone. more...

This paper discusses the design and application of in-situ particulate sampling systems in evaluating the performance of high-temperature, high-pressure (HTHP) gas-filtration systems at the Power Systems Development Facility (PSDF) in Wilsonville, Alabama. Initial operating experience with the sampling systems is reviewed, and results of initial sampling runs are discussed. more...

An alkoxytitanium carboxylate of a branched carboxylic acid was synthesized and its effectiveness as a dispersant for oxide powders determined. The amount of titanate required to produce stable dispersions & nonaqueous media corresponded to monomolecular layer coverage of the oxide particles by the titanate. Low-molecular-weight organotitanate dispersants should prove useful as substitutes for fish oil or polymers in ceramics processing. more...

The Klippel-Trenaunay Syndrome is a triad of congenital anomalies characterized by a vascular naevus, varicose veins and hypertrophy of soft tissue and bone. A number of patients affected with this rare syndrome need amputation. In this paper the systemic problems, stump complications and prosthetic difficulties of four amputees with Klippel-Trenaunay syndrome are outlined. The period of follow-up ranged from 10 to 24 years after amputation. more...