1. Department of Medicine, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
2. Department of Population Health Sciences, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
3. Charlie Norwood VA Medical Center, Augusta, GA 30904, USA
4. Department of Physiological and Technological Nursing, Augusta University, Augusta, GA 30912, USA
5. Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA