Funding for this research was provided by:
Internal research fund of the Hannover Medical School (79273002)
Received: 15 December 2017
Accepted: 6 February 2018
First Online: 17 February 2018
Ethics approval and consent to participate
: The study was approved by the ethics committee of the Hannover Medical School in December 2014 (No.: 2499–2014). All participants in this study gave informed consent prior to any procedure.
: Not applicable.
: The authors declare that they have no competing interests.
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