Sun, H
Stockbridge, N
Ariagno, R L
Murphy, D
Nelson, R M
Rodriguez, W
Article History
Received: 2 November 2015
Revised: 29 March 2016
Accepted: 11 April 2016
First Online: 14 July 2016
Competing interests
: Views expressed in this manuscript are those of the authors and do not necessarily reflect official positions or policies of the FDA. This research received no grant from any funding agency in the public, commercial or not-for-profit sectors. The authors declare no conflict of interest.