1. Cardiothoracic Surgery & Transplant Research Center, Emam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
2. Chronic Obstructive Pulmonary Disease Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
3. Student Research Committee, Faculty of medicine, Mashhad University of Medical Sciences, Mashhad, Iran