Liang, X
Ding, Y
Zhang, Y
Chai, Y-H
He, J
Chiu, S-M
Gao, F
Tse, H-F
Lian, Q
Article History
Received: 12 September 2014
Revised: 14 January 2015
Accepted: 16 February 2015
First Online: 21 May 2015
Competing interests
: The authors declare no conflict of interest.