1. Department of Bioengineering, Clemson University, Clemson, South Carolina 29634-0905.
2. NASA Lewis Research Center, Cleveland, Ohio 44135.
3. Institut fŭr Pathologie, Universităt Mainz, Germany.
4. Abteilung fūr Paradontologie, Klinikum der J-L Universităt Gießen, Germany.