6979
SEC analysis of the acL - CHP nanogel at pH 4 . 0 showed that the grafts were nearly 80 % degraded after 24 h , whereas little or no degradation was observed over the same time period for a pH stable analog ( acS - CHP ) at pH 4 . 0 or the acL - CHP at pH 7 . 0 .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None