19 research outputs found
Recommended from our members
Design and analysis of a structural system for ZTH
A structural support system comprised largely of laminated epoxy fiberglass bulkheads has been designed for the ZTH air core machine, the initial experiment in the Confinement Physics Research Facility (CPRF) at LANL. Fiberglass was chosen to minimize magnetic field errors due to eddy currents. Magnetic fields for ZTH are produced, in part, by 18 poloidal field (PF) coils. Sixteen, equally spaced, 4 inch thick, radial G-10 bulkheads, positioned and held by a series of stainless steel ring beams, support the PF coils and the toroidal front end assembly. PF coils transfix and are supported by the bulkheads at locations dictated by magnetic field effects. The toroidal front end is mounted to the bulkheads by a spline ensuring constant alignment with the coil set while allowing differential expansion. The entire machine assembly is mounted on a central concrete cylinder with outboard stainless steel columns. Finite element analyses were performed as an integral part of the design process for the ZTH structure. Because of irregular shapes, multiple materials, different load cases and numerous geometric discontinuities conventional analyses of the structure could not be performed. Static and dynamic coil loads were applied to a model of the prototype support system to examine structural response. A discussion of the model, assumptions, load cases, boundary conditions, and results is given. Influence of the results on the design are presented. 3 refs
Patogênese e achados clínicos, hematológicos e anatomopatológicos da infecção por Rangelia vitalii em 35 cães (1985-2009)
Resolution of renal adenocarcinoma-induced secondary inappropriate polycythaemia after nephrectomy in two cats
Injury-induced class 3 semaphorin expression in the rat spinal cord
In this study we evaluate the expression of all members of the class 3 semaphorins and their receptor components following complete transection and contusion lesions of the adult rat spinal cord. Following both types of lesions the expression of all class 3 semaphorins is induced in fibroblast in the neural scar. The distribution of semaphorin-positive fibroblasts differs markedly in scars formed after transection or contusion lesion. In contusion lesions semaphorin expression is restricted to fibroblasts of the meningeal sheet surrounding the lesion, while after transection semaphorin-positive fibroblast penetrate deep into the center of the lesion. Two major descending spinal cord motor pathways, the cortico- and rubrospinal tract, continue to express receptor components for class 3 semaphorins following injury, rendering them potentially sensitive to scar-derived semaphorins. In line with this we observed that most descending spinal cord fibers were not able to penetrate the semaphorin positive portion of the neural scar formed at the lesion site. These results suggest that the full range of secreted semaphorins contributes to the inhibitory nature of the neural scar and thereby may inhibit successful regeneration in the injured spinal cord. Future studies will focus on the neutralization of class 3 semaphorins, in order to reveal whether this creates a more permissive environment for regeneration of injured spinal cord axons