A discrete mechanics framework for real time virtual surgical simulations with application to virtual laparoscopic nephrectomy.

The inability to render realistic soft-tissue behavior in real time has remained a barrier to face and content aspects of validity for many virtual reality surgical training systems. Biophysically based models are not only suitable for training purposes but also for patient-specific clinical applications, physiological modeling and surgical planning. When considering the existing approaches for modeling soft tissue for virtual reality surgical simulation, the computer graphics-based approach lacks predictive capability; the mass-spring model (MSM) based approach lacks biophysically realistic soft-tissue dynamic behavior; and the finite element method (FEM) approaches fail to meet the real-time requirement.

Novel heat conduction model for bridging different space and time scales.

This exposition describes a novel heat transport model and an underlying unified theory emanating from the physics of the Boltzmann transport equation which acknowledges simultaneously the coexistence of that termed as slow processes (at low energies) and fast processes (at high energies) as heat carriers while describing the evolution of heat transport characteristics spanning both spatial scales (characterizing ballistic to diffusive limits), and also time scales (characterizing finite to infinite heat propagation speeds).