Liu, H http://orcid.org/0000-0001-7984-6305
Lu, J
Hua, Y
Zhang, P
Liang, Z
Ruan, L
Lian, C
Shi, H
Chen, K
Article History
Received: 5 August 2014
Revised: 22 November 2014
Accepted: 26 November 2014
First Online: 15 January 2015
Competing interests
: The authors declare no conflict of interest.