1. Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials and Science and Engineering East China University of Science and Technology Shanghai 200237 P. R. China
2. State Key Laboratory of Bioreactor Engineering East China University of Science and Technology Shanghai 200237 P. R. China
3. Department of General Surgery Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Shanghai 200092 P. R. China
4. Shanghai Research Center of Biliary Tract Disease Shanghai Key Laboratory of Biliary Tract Disease Yangpu District Shanghai 200092 P. R. China