Lu, L
Zou, Y-C
Wang, M
Huang, Y-F
Chen, D-X
Wei, L-B
Article History
Received: 13 October 2014
Revised: 5 March 2015
Accepted: 15 March 2015
First Online: 29 April 2015
Competing interests
: We declare that we have no financial or personal relationships with other people or organisations that can inappropriately influence our work; there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, this manuscript.