Text and Data Mining valid from 2019-03-07
Received: 15 January 2019
Accepted: 27 February 2019
First Online: 7 March 2019
Compliance with ethical standards
: The authors declare no competing interests for this manuscript.
: All procedures in studies involving human participants were in accordance with the Ethical Standards of the institutional and /or national research committee 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.