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A combinational intragastric administration of 40mg / kg atRA can partially reverse NiCl ( 2 ) - induced arrhythmia in rats .
 Chemical: atRA; Chemical: NiCl ( 2 )
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: atRA, NiCl ( 2 ) 
Answer:
 Chemical: atRA; Chemical: NiCl ( 2 )