Li, Zhen
Jiao, Yanmei
Hu, Yu
Cui, Lianxian
Chen, Dexi
Wu, Hao
Zhang, Jianmin
He, Wei
Article History
Received: 9 March 2014
Revised: 22 July 2014
Accepted: 25 July 2014
First Online: 15 September 2014
Competing interests
: The authors have declared no conflicts of interest in this study.