13438
The GIPAW method was used to compute the NMR shielding parameters for the different models , which included the alpha - PLLA structure obtained by 2 - dimensional wide - angle X - ray diffraction ( WAXD ) at - 150 degrees C ( model M1 ) and at 25 degrees C ( model M2 ) , neutron diffraction ( WAND ) measurements ( model M3 ) and the fully optimized geometry of the PLLA chains in the unit cell with defined size ( model M4 ) .
 Chemical: alpha - PLLA
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: alpha - PLLA