6455
Cryogenic transmission electron microscopy ( Cryo - TEM ) revealed a continuous network of fibers throughout the hydrogel sample , even at concentrations as low as 0 . 25 wt % .
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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:
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