8576
In this study , anodic TiO ( 2 ) nanotubes have been selectively closed by high energy focused ion beams and re - opened by low energy focused ion beams .
 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: TiO ( 2 )