3274
The subjects were exposed to cold air (4 degrees C) twice/d, 30 min/exposure, for a total of 80 exposures.
 None
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 None