1. Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
2. Department of Dermatology, Emory School of Medicine, Atlanta, GA 30322, USA.
3. Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA.
4. UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
5. Deparment of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
6. Atlanta Veterans Administration Medical Center, Atlanta, GA 30322, USA.