Text and Data Mining valid from 2018-07-25
Received: 5 May 2018
Accepted: 3 July 2018
First Online: 25 July 2018
Ethics approval and consent to participate
: Ethics approval was permitted by ethics committee of Xuan Wu Hospital, Capital Medical University.The consents to participate are stored in Ethics office.
: Not applicable.
: The authors declare that they have no competing interests.