1. Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
2. Division of Cardiothoracic Surgery, Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
3. Lenox Hill Hospital, New York, New York 10075, USA
4. Integris Baptist Medical Center, Oklahoma City, Oklahoma 73112, USA