Received: 9 December 2019
Accepted: 21 March 2020
First Online: 5 June 2020
Compliance with ethical standards
: Zhirong Liu, Zhen Zhang, Hao Mei, Jinghe Mao, Xinchun Zhou declare no conflict of interest.
: This study was approved by Institutional Review Board of University of Mississippi Medical Center.
: No consent form was needed.