Received: 18 July 2018
Accepted: 6 November 2018
First Online: 22 November 2018
Ethics approval and consent to participate
: The study was performed in accordance with the ethics standards at the Techniqueal University of Munich (TUM) (ethical vote: 28.02.2018s, 88/18 S).Name of committee: Ethikkommission der Technischen Universität München.
: Not applicable
: The authors declare that they have no competing interests.
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