. 2014 Apr 23;12:106. doi: 10.1186/1477-7819-12-106
Copyright © 2014 Chen et al.; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.