. 2013 Aug 26;8:3271–3283. doi: 10.2147/IJN.S47597
© 2013 Deng et al. This work is published by Dove Medical Press Ltd, and licensed under Creative Commons Attribution – Non Commercial (unported, v3.0) License
The full terms of the License are available at http://creativecommons.org/licenses/by-nc/3.0/. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Ltd, provided the work is properly attributed.