Received: 12 November 2018
Accepted: 17 July 2019
First Online: 27 July 2019
Ethics approval and consent to participate
: All procedures were performed in accordance with the ethical standards of the institutional review board of the Ludwig-Maximilians-University of Munich (LMU) (votum no. 507–14) and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed written consent and permission was obtained from all individual participants included in the study.
: Written informed consent to publish was obtained from all individual participants included in the study.
: The authors declare that they have no competing interests.