Ha, Y
Liu, H
Xu, Z
Yokota, H
Narayanan, S P
Lemtalsi, T
Smith, S B
Caldwell, R W
Caldwell, R B
Zhang, W
Article History
Received: 29 March 2015
Revised: 18 August 2015
Accepted: 2 September 2015
First Online: 8 October 2015
Competing interests
: The authors declare no conflict of interest.