11071
Using the relationship between these responses to 4 - week inhalation and intratracheal instillation , it may be possible to estimate what aerosol concentrations of other nanomaterials might cause the same responses of PMN production as intratracheal instillation tests .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
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