Wang, Ruping
Xu, Huiyong
Du, Liangcheng
Chou, Shan-Ho
Liu, Hongxia
Liu, Youzhou
Liu, Fengquan
Qian, Guoliang
Article History
Received: 4 March 2016
Accepted: 25 April 2016
First Online: 31 May 2016
Competing interests
: The authors declare no competing financial interests.