Text and Data Mining valid from 2018-04-04
First Online: 4 April 2018
Compliance with ethical standards
: The authors declare that they have no conflicts of interest.
: All procedures performed 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. For this study, informed consent was waived by the institutional review board where the study took place.