Fig. 1From: Calcium-dependent cyto- and genotoxicity of nickel metal and nickel oxide nanoparticles in human lung cellsNanoparticle characterization. a TEM images showing Ni NPs (left, bar indicates 10Â nm) and NiO NPs (right, bar indicates 50Â nm). b Fitted XPS spectra of Ni and NiO confirming the composition of the surface of the NPs. c Intrinsic ROS production measured using the DCFH assay without HRP (left) and with HRP (right)Back to article page