Received: 10 December 2020
Accepted: 2 February 2021
First Online: 12 February 2021
Ethics approval and consent to participate
: The study was approved by the local ethics committee of the University of Freiburg (327/20) and all procedures were in accordance with the latest revision of the Declaration of Helsinki. Written informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.