1. Department of Pharmaceutical Sciences, University of Ferrara, Ferrara, Italy
2. Division of Clinical Virology, Huddinge University Hospital, Huddinge/Stockholm, Sweden
3. Computer-aided Systems Laboratory, Department of Chemical Engineering, University of Trieste, Trieste, Italy
4. Istituto di Genetica Molecolare, CNR, Pavia, Italy
5. Rega Institute for Medical Research, Katholieke Universiteit Leuven, Leuven, Belgium