I am deeply indebted to Dr. Dave Rea for his support during this project, particularly the generous access to his laboratory and Coulter Counter equipment and especially his moral and scientific guidance. Steve Clemens and Eve Arnold were very helpful in their reviews of this manuscript, and their insight was greatly appreciated. This work was supported by funding provided by USSSP, an Indiana University of Pennsylvania Senate grant, and a National Science Foundation summer internship program for undergraduates.