1. Department of Medicine, University of Vermont, Burlington, Vermont.
2. Unit of Biophysics and Bioengineering, University of Barcelona, Barcelona, Spain.
3. CIBER Enfermedades Respiratorias, Madrid, Spain.
4. Comprehensive Pneumology Center, Helmholtz Center Munich, Ludwig Maximilians University Munich, University Hospital Grosshadern, Member of the German Center for Lung Research (DZL), Munich, Germany.