Funding for this research was provided by:
National Institute on Drug Abuse (R25DA031608)
National Institute on Drug Abuse (K01DA033879)
National Institute on Drug Abuse (R01DA024598)
National Institute on Drug Abuse (R01DA033862)
National Institute on Drug Abuse (R03DA039740)
National Institute of Allergy and Infectious Diseases (R21AI131979)
Article History
First Online: 15 October 2018
Compliance with Ethical Standards
: All study procedures and materials were reviewed and approved by the Institutional Review Boards at Boston University and the Pacific Institute for Research and Evaluation.