12298
Considering that the reactor is thoroughly mixed during each discharge and that LD50 = 0 . 9 values are nearly independent of E . coli concentrations in the range of 2 x 10 ( 3 ) < or = E coli / cfu mL ( - 1 ) < or = 3 x 10 ( 6 ) , we ascribe the nonexponential Pn decay of single - strain E . coli colonies to a shielding phenomenon where inactive cells protect the successively smaller numbers of viable cells in the EHD .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
 Entities:  
Answer:
 None