. 2014 Oct 20;3:180. Originally published 2014 Jul 31. [Version 2] doi: 10.12688/f1000research.4856.2
Copyright: © 2014 Guo T et al.
This is an open access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Data associated with the article are available under the terms of the Creative Commons Zero "No rights reserved" data waiver (CC0 1.0 Public domain dedication).