the concentrations of borax ore , kernite ore , and refined borax that reduced the relative plating efficiency to 50 % were approximately 3.2 , 1.6 , and 0.8 mg/ml , respectively , in human fibroblasts and were 0.8 mg/ml for all three substances in c3h/10t1/2 cells .
C0016030
fibroblasts
C0007634
cells