Table 3.

Expected and observed amounts of apoptosis for combined low-dose alpha-particle irradiation and low-dose uranium exposure

No. of embryosa	Expected	Observed	P (Case 1b)	P (Case 2c)	Interaction
144	−0.58 ± 0.03	−0.15 ± 0.04	7.06 × 10–11	3.16 × 10–11	Antagonistic

The expected values (N_{<I L>UL} or N_{I L<UL>}) and observed values (N_ILUL ^†) of apoptosis for the combined effects of ∼0.44 mGy alpha-particle irradiation and exposure to 10 µg/l uranium concentration for 1 h on the 24 hpf Zebrafish embryos, indicating whether the interactions were additive, synergistic or antagonistic. ^aReferring to the total number of embryos in all four sets of samples. ^bN_IL ^† was added to each embryo in the U_L group. ^cN_UL ^† was added to each embryo in the I_L group.