Li, Li
Wang, Liyan
Wu, Zhiqin
Yao, Lijun
Wu, Yonghou
Huang, Lian
Liu, Kan
Zhou, Xiang
Gou, Deming
Article History
Received: 16 April 2014
Accepted: 11 August 2014
First Online: 29 August 2014
Competing interests
: The authors declare no competing financial interests.