Received: 29 March 2019
Accepted: 20 January 2020
First Online: 5 February 2020
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: The research was approved by the local ethics committee (University of Wroclaw, no 01/E/10/2017). All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.