25227
Generation of reactive oxygen species , one of the proposed toxicological mechanisms of NPs , was investigated in A549 cells by the dichlorofluorescin ( DCF ) assay to be significantly induced at NP concentrations above 113 mu g / mL .
 Chemical: oxygen; Chemical: dichlorofluorescin; Chemical: DCF
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: oxygen; Chemical: dichlorofluorescin; Chemical: DCF