19500
The half - life of HK - SLEs ( t1 / 2 ( alpha ) = 8 . 014 min , t1 / 2 ( beta ) = 35 . 784 min ) was remarkably prolonged compared to that of HK - SOL ( t1 / 2 ( alpha ) = 4 . 318 min , t1 / 2 ( beta ) = 15 . 522 min ) .
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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