Text and Data Mining valid from 2019-01-14
Received: 22 August 2018
Accepted: 6 January 2019
First Online: 14 January 2019
Compliance with ethical standards
: The authors have declared that no conflict of interest exists.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee at which the studies were conducted (IRB approval number 29–94) 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.