Wang, L
Li, H
Ren, Y
Zou, S
Fang, W
Jiang, X
Jia, L
Li, M
Liu, X
Yuan, X
Chen, G
Yang, J
Wu, C
Article History
Received: 22 August 2015
Revised: 25 September 2015
Accepted: 6 October 2015
First Online: 21 January 2016
Competing interests
: The authors declare no conflict of interest.