1. Betty and Guy Beatty Center for Integrated Research, Inova Health System, Falls Church, Virginia, USA
2. Center for the Study of Chronic Illness and Disability, George Mason University, Fairfax, Virginia, USA
3. American Institute for Research, Washington, DC, USA
4. Craig Center for Regenerative Research, University of Colorado, Englewood, Colorado, USA
5. Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA