The acknowledgements to this article have been updated from their original published display to provide additional specific details on the sources of the funding for the grant numbers supporting this study. The new funding statement appears below:
“This study was supported by grants to SK-S through National Institute on Drug Abuse (NIDA) grants P50DA009241 and P50DA036151 from the NIDA and FDA Center for Tobacco Products (CTP). The efforts of DRC and GK were also supported by K12DA033012, Clinical and Translational Science Award grants UL1 TR000142, and KL2 TR000140 from the National Center for Advancing Translational Science (NCATS), components of the National Institutes of Health (NIH), and NIH Roadmap for Medical Research. The funders had no role in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the article for publication.”