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Article History

Received: 23 January 2019

Accepted: 8 April 2019

First Online: 24 April 2019

Ethics approval and consent to participate

: No human subjects were involved in this study. For the procedures used and material collected, no formal ethics approval is needed. All experimental procedures and animal handling complied with the guidelines of Norwegian regulation for laboratory animal experimentation (The Norwegian Animal Protection Act, No. 73 of 20 December 1974, Section 20–22, amended 19 June 2009).

: Not applicable.

: The authors declare no competing interests.

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