21810
For fluorescein , the results showed that the obstruction factor , which is the ratio of the diffusion coefficients inside the media and in open solution , is equal to the porosity within experimental error .
 Chemical: fluorescein
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: fluorescein 
Answer:
 Chemical: fluorescein