2853
Mice null for both NPY and leptin ( NPY ( - / - ) ob / ob ) , display greater cortical bone mass in both long - bones and vertebra , with NPY ( - / - ) ob / ob mice exhibiting thicker and denser cortical bone , associated with greater endocortical and periosteal mineral apposition rate ( MAR ) , compared to ob / ob animals .
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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