Funding for this research was provided by:
Deutsche Forschungsgemeinschaft (DFG 3759/4-1)
Received: 17 December 2018
Accepted: 14 January 2020
First Online: 31 January 2020
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures 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. This article does not contain any studies with animals performed by any of the authors.
: Informed consent was obtained from all individual participants included in the study.