1. Critical Care Medicine Department, National Institutes of Health (NIH) Clinical Center, Bethesda, MD;
2. Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA;
3. Department of Physics and the Translational Science Center, Wake Forest University, Winston-Salem, NC;
4. Laboratory of Pathology, National Cancer Institute, NIH, Bethesda, MD;
5. Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA; and
6. Department of Transfusion Medicine, NIH Clinical Center, Bethesda, MD