Funding for this research was provided by:
University of Innsbruck and Medical University of Innsbruck
Article History
Received: 17 January 2018
Accepted: 23 March 2018
First Online: 13 April 2018
Conflict of interest
: L. Gasteiger, S. Eschertzhuber and W. Tiefenthaler declare that they have no competing interests.