Text and Data Mining valid from 2019-02-09
Received: 13 May 2018
Accepted: 1 February 2019
First Online: 9 February 2019
Compliance with ethical standards
: All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committees and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.