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Here , on the basis of a comprehensive analysis of long ( 5 - 10 mm ) individual polyacrylonitrile nanofibers , we show that nanofiber toughness also dramatically improves .
 Chemical: polyacrylonitrile
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: polyacrylonitrile