1. Department of Biomedical Engineering, Michigan Technological University, Houghton, Michigan 49931;
2. Nerites Corporation, Madison, Wisconsin 53719
3. Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60201;
4. Department of Chemical Engineering, University of California, Santa Barbara, California 93106;
5. Molecular, Cell & Developmental Biology, University of California, Santa Barbara, California 93106;