3943
Cells exposed to TiO ( 2 ) NPs ( 10 and 50 mu g / ml ) for 6 - 24 h shows significant induction in oxidative stress , that is , the production of reactive oxygen species and malondialdehyde and decrease in the activity of catalase and glutathione .
 Chemical: TiO ( 2 ); Chemical: oxygen; Chemical: malondialdehyde; Chemical: glutathione
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: TiO ( 2 ); Chemical: oxygen; Chemical: malondialdehyde; Chemical: glutathione