Li, Jing
Liu, Mengchun
Zong, Jinbao
Tan, Ping
Wang, Jingli
Wang, Xunfeng
Ye, Yuanhua
Liu, Shiguo
Liu, Xuemei
Article History
Received: 14 March 2014
Accepted: 15 May 2014
First Online: 11 June 2014
Competing interests
: The authors declare no competing financial interests.