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Thus , our results further confirmed the critical role of ROS and histone hypoacetylation in the cytotoxicity of Ni ( 2 + ) exposure and proved that QU is a potentially useful native dietary compound to efficiently prevent Ni ( 2 + ) - caused cytotoxicity through both diminishing ROS generation and increasing histone acetylation .
 Chemical: Ni ( 2 + ); Chemical: Ni ( 2 + )
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: Ni ( 2 + ); Chemical: Ni ( 2 + )