1. Division of Pulmonary, Asthma, and Sleep Medicine, Center for Excellence in Pulmonary Biology, and
2. Division of Pediatric Critical Care Medicine, Department of Pediatrics, Stanford University School of Medicine, Stanford, California;
3. Metabolomics and Analytics Centre, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands; and
4. Comprehensive Pneumology Center, Ludwig Maximilian University of Munich, Munich, Germany