Funding for this research was provided by:
European Community's Seventh Framework Programme (611736)
Received: 19 December 2017
Accepted: 14 March 2018
First Online: 27 March 2018
Ethics approval and consent to participate
: This research project was reviewed by the South African Medical Research Council, Waterford Institute of Technology and Kings College London, and ethics approval was obtained. Proof of ethics approval can be provided upon request.
: Not applicable.
: The authors declare that they have no competing interests.
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