Wang, Ningjian
Zhai, Hualing
Han, Bing
Li, Qin
Chen, Yi
Chen, Yingchao
Xia, Fangzhen
Lin, Dongping
Lu, Yingli
Article History
Received: 2 September 2015
Accepted: 18 December 2015
First Online: 22 January 2016
Competing interests
: The authors declare no competing financial interests.