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Therefore , the main objective of this work was to investigate the effects of two types of TiO2 NPs , with different crystalline structure , on human SHSY5Y neuronal cells .
 Chemical: TiO2
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: TiO2