1. Department of Mechanical and Aerospace Engineering, University of California, Davis, California 95616, USA
2. Department of Mathematics, University of California, Davis, California 95616, USA
3. Department of Biomedical Engineering, Ben Gurion University of the Negev, Be'er Sheva 84105, Israel
4. Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be'er Sheva 84105, Israel