1. Department of Thoracic Surgery, The Fourth Hospital of Hebei Medical University, Shijiazhuang, P.R. China.
2. Department of Cardiothoracic Surgery, The Third Hospital of Shijiazhuang, Shijiazhuang, P.R. China.
3. Department of Laboratory Medicine, Children's Hospital of Hebei Province, Shijiazhuang, P.R. China.