Received: 11 September 2017
Accepted: 15 May 2018
First Online: 1 June 2018
Ethics approval and consent to participate
: This study was approved by the University of Kent’s Research and Ethics Committee (Prop. 163–2013). Informed consent was obtained from all participants.
: Consent for publication was sought from all participants whose images are contained in this manuscript.
: The authors declare they have no competing interests.
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