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Article History

Received: 12 December 2017

Accepted: 12 May 2018

First Online: 22 June 2018

Compliance with ethical standards

:

: There are no conflicts of interest with regard to this study or funding from any company.

: The study was approved by the local committee for Ethics . All procedures performed in studies involving human participants were in accordance with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

: For this type of study formal consent is not required.