28923
A combination of two factors , namely , nature of the - O - CH2 - linkage in the LNAs vs their absence in the pure duplexes and similar conformations of the sugar rings in DNA and alpha - LNA vs the other two , is suggested to contribute to the stark differences among the four duplexes studied here in terms of their structural , dynamic , and energetic properties .
 Chemical: O - CH2
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: O - CH2