1. Department of Pulmonary and Critical Care Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea;
2. Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea;
3. Premedical Science, College of Medicine, Chosun University, Gwangju, Republic of Korea;
4. Department of Bio-Medical Sciences, College of Medicine, Chosun University, Gwangju, Republic of Korea