A porcine model was devised to investigate Doppler waveforms in dysfunctional renal allografts. NIH miniature pigs served as allografts donors and recipients. Renal transplantation was effected into ...the recipient pelvis while the left normotopic kidney was subjected to warm ischemia in order to induce acute tubular necrosis (ATN). Doppler demonstration of allograft arterial occlusion in six animals was confirmed at surgery. Increased pulsatility of intrarenal arterial signals constituted evidence of vascular rejection in two animals. Biopsies confirmed the diagnosis in both cases. Histologic changes of ATN were identified in two native kidneys subjected to ischemia. No waveform or pulsatility alterations were observed in these animals. The porcine model provides for the investigation of allograft Doppler waveforms in a controlled setting with free access to biopsy and operative pathologic correlation.
Summary form only given, as follows. A new 3D finite element gun and collector modeling code is under development at SAIC in collaboration with industrial partners and National Laboratories. This ...development program has been designed specifically to address the shortcomings of current simulation and modeling tools. In particular, although there are 3D gun codes that exist today, their ability to address fine scale features is somewhat limited in 3D due to disparate length scales of certain classes of devices. Additionally, features like advanced emission rules, including thermionic Child's law and comprehensive secondary emission models also need attention. The program specifically targets problems classes including gridded-guns, sheet-beam guns, multi-beam devices, and anisotropic collectors. The presentation provides an overview of the program objectives, the approach to be taken by the development team, and a status of the project.
