Received: 28 July 2019
Accepted: 29 April 2020
First Online: 18 May 2020
Ethics approval and consent to participate
: All investigations were performed in strict compliance with the restrictions of the German Animal Protection Law. For the study images acquired for previous research projects were assessed, thus approval from the Committee on the Ethics of Animal Experiments of the Justus-Liebig-University and the local Hessian government was not required.
: Not applicable.
: The authors declare that they have no competing interests.