Funding for this research was provided by:
Foundation for the National Institutes of Health (NIDA R25 DA031608-01)
University of California, San Diego (3-P3035)
California HIV/AIDS Research Program (HD15-SD-059)
National Institute on Drug Abuse Intramural Research Program
Received: 25 June 2019
Accepted: 26 May 2020
First Online: 11 June 2020
Ethics approval and consent to participate
: All participants provided written informed consent. This study was approved by the Institutional Review Board at the University of California, San Diego.
: All authors reviewed this manuscript and consent to its publication.
: The authors declare that there they have no competing interests.