19737
The decreased level of cell toxicity for small AgNPs was 32 +/- 0 . 7 % , whereas it was only 10 . 6 +/- 5 . 2 % for large AgNPs kept 24h under light irradiation .
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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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