7278
Ultrasonic frequencies of 20kHz , 382kHz , 584kHz , 862kHz ( and 998kHz ) have been compared with regard to energy output and hydroxyl radical formation utilising the salicylic acid dosimeter .
 Chemical: hydroxyl; Chemical: salicylic acid
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: hydroxyl; Chemical: salicylic acid