close to significanceP = 0.053
Replacing ammonium nitrate with a labelled counterpart ( 15 NH 4 15 NO 3 ) did not significantly affect cell viability (two‐sided, two‐sample Welch test, α = 0.05, N = 12, P = 0.222), but was close to significance when combined with 50% v/v deuterium oxide (two‐sided, two‐sample Welch test, α = 0.05, N = 12, P = 0.053; Figure 1c and Table 1 ).