Zhe, Zhang
Bo, Yang http://orcid.org/0000-0001-9609-6366
Article History
Received: 26 February 2018
Revised: 21 May 2018
Accepted: 6 June 2018
First Online: 15 June 2018
Compliance with ethical standards
: The study was reviewed and approved by the Ethical Inspection Committee of Zhengzhou University and all participants conformed and signed the informed content.
: The authors declare that they have no conflicts of interest.