1. Dynamical Systems Group, School of Engineering, Rice University, Houston, TX 77005, USA
2. Biomedical Engineering Center, University of Texas Medical Branch, Galveston, TX 77555, USA
3. Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
4. Department of Thoracic Surgery, University of Texas Medical Branch, Galveston, TX 77555, USA