Similarity of sputum mediator signatures between e-cigarette users and COPD depends on GOLD stage and type of e-cigarette: a pilot study - Elise Hickman; William Dabbs; Heather Wells; R. Graham Barr; Prescott Woodruff; Jill Ohar; Fernando J. Martinez; Russell Bowler; Christopher B. Cooper; Jeffrey L. Curtis; J. Michael Wells; Wassim W. Labaki; et al. (PLoS ONE, 2026)