Received: 29 November 2018
Accepted: 4 February 2019
First Online: 11 February 2019
Ethics approval and consent to participate
: This study was performed in accordance with institutional review board approval by the local ethical committees (ethical committee of northwestern and central part of Switzerland, (EKNZ) and cantonal ethical committee Zurich (KEK), approval number 2016–01062).
: Not applicable.
: The authors declare that they have no competing interests.
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