Joseph D. Keegan

JOSEPH D. KEEGAN, PhD was appointed President and Chief Executive
Officer of the company effective March 30, 1998. From 1992 to 1998, Dr.
Keegan served in various positions at Becton Dickinson and Company, a
research and diagnostic company, including the positions of Vice
President, Sales and Service, Vice President, General Manager of the
Immunocytometry Systems Division and President of the Worldwide Tissue
Culture Business. From 1987 to 1992, he was employed by LEICA, Inc., a
microscope manufacturer, where he held various senior management
positions. Dr. Keegan holds a PhD in Chemistry from Stanford University.