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A particular emphasis is placed on protein NMR and hydrogen / deuterium exchange ( HDX ) techniques and how they provide complementary information that , when combined with crystallography , provide detailed insight into the function of nuclear receptors .
 Chemical: hydrogen; Chemical: deuterium
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: hydrogen; Chemical: deuterium