Received: 14 April 2018
Accepted: 26 March 2019
First Online: 9 April 2019
Ethics approval and consent to participate
: Full departmental, institutional, and local ethical committee approval of the University Hospital Tübingen/Germany were obtained before commencement of the study (project number 122/2012B02). Written informed consent was received from all subjects before participation.
: Not applicable.
: The authors declare that they have no competing interests.
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