22503
ROS activity was measured by the nitroblue tetrazolium reduction assay and visualized by fluorescent microscopy .
 Chemical: nitroblue tetrazolium
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: nitroblue tetrazolium