Funding for this research was provided by:
Defense Health Agency (HU0001-11-1-0023)
Received: 15 February 2018
Accepted: 5 September 2018
First Online: 17 September 2018
Ethics approval and consent to participate
: This study received Institutional Review Board (IRB) approval through the Uniformed Services University in Bethesda, Maryland.
: Not applicable.
: The authors declare that they have no competing interests.
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