1. Key Laboratory of Leather Chemistry and Engineering of Ministry of Education; Sichuan University; Chengdu 610065 China
2. ISM, UMR CNRS 5255; Univ. Bordeaux; 33405 Talence Cedex France
3. Facultad de Chimica de San Sebastian; Universidad del Pais Vasco; Apdo 1072 20080 San Sebastian Spain