Text and Data Mining valid from 2020-02-03
Received: 10 June 2019
Accepted: 20 January 2020
First Online: 3 February 2020
Ethics approval and consent to participate
: Local ethics committee (Pavlov First Saint Petersburg State Medical University, Russia) approval was obtained to conduct this study. All patients were consented to participate in the study. Specifically written informed consent was obtained from the participants. There are no patient identifying information in the manuscript.
: Not applicable.
: The author(s) declare(s) that they have no competing interests. Dr. Zhamshid Okhunov, as a member of the editorial board (Section Editor) of this journal, had no role in the handling this manuscript.