Yu, X
Zhang, L
Wen, G
Zhao, H
Luong, L A
Chen, Q
Huang, Y
Zhu, J
Ye, S
Xu, Q
Wang, W
Xiao, Q
Article History
Received: 18 February 2014
Revised: 5 November 2014
Accepted: 6 November 2014
First Online: 19 December 2014
Competing interests
: The authors declare no conflict of interest.