Wang, Wei
Ma, Ting
Zhang, Baoliang
Yao, Nana
Li, Mingchang
Cui, Lianlei
Li, Guoqiang
Ma, Zhenping
Cheng, Jiansong
Article History
Received: 20 August 2014
Accepted: 14 November 2014
First Online: 2 December 2014
Competing interests
: The authors declare no competing financial interests.