2420
Over half of the Fe ( 3 ) O ( 4 ) - NPs were retained in the striata for a minimum of 14 days , and may have induced oxidative damage to the region .
 Chemical: Fe ( 3 ) O ( 4 )
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: Fe ( 3 ) O ( 4 )