Dear Dr. Wassenaar, many thanks for your kind reply. Andrea -- ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ Andrea Carotti Dipartimento di Chimica e Tecnologia del Farmaco Università di Perugia Via del Liceo, 1 06123 Perugia, Italy phone: +39 075 585 5169 fax: +39 075 585 5161 www http://rpg.unipg.it personal www http://iris.chimfarm.unipg.it/users/andcar