Affiliation: | 1. Department of Chemical and Biological Engineering, University of Sheffield, Mappin St., Sheffield S1 3JD, UK;2. telephone: +44‐114‐222‐7505;3. fax: +44‐114‐222‐7501;4. BioTherapeutics Research and Development, Pfizer Corporation, 700 Chesterfield Parkway West, Chesterfield, Missouri 63017 |