10121
Upon photoactivation , a larger number of hydroxyl radicals were detected from TiO ( 2 ) particles with larger surface area , again suggesting a surface area dependent phototoxic effect .
 Chemical: hydroxyl; Chemical: TiO ( 2 )
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: hydroxyl; Chemical: TiO ( 2 )