1 Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Xi'an, China Institute of Advanced Surgical Technology and Engineering, Xi'an, China, Department of Hepatobiliary Surgery, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Xi'an, China Institute of Advanced Surgical Technology and Engineering, Xi'an, China, rwu001@mail.xjtu.edu.cn.