Thus , the detection of traces of COMPOUND_XXX in some of the control group samples is considered not to impair the achievement of the study objectives or the overall validity of the study .
Thus , the detection of traces of COMPOUND_XXX in some of the control group samples is considered not to impair the achievement of the study objectives or the overall validity of the study .
O O O O O O O O O O O O B-GROUP I-GROUP O O O O O O O O O O O O O O O O O O O O