13322
The D - spacing distribution on phlogopite mica is independent of type I collagen concentration , but on muscovite mica D - spacing distributions showed increased negative skewness at 20 mu g / mL and higher concentrations .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 None