TABLE 1.
Parameters Gbase(fr), Gsugar(fr), kbase and ksugar Obtained by Fitting to the Two-Component Model, the Dose–Response Curve for pUC18 Plasmid Film Samples at Various Γ (mol water/mol nucleotide)a
pUC18 plasmids | Gbase(fr) (μ mol/J) | Gsugar(fr) (μ mol/J) | kbase (kGy −1) | ksugar (kGy−1) | G(∑fr) (μmol/J) | Gbase(fr)/G(∑ fr) | G(∑fr)/Ginitial(fr) |
---|---|---|---|---|---|---|---|
at Γ ~2.5 | 0.253 (0.008) | 0.032 (0.0004) | 0.033 (0.001) | 0.0004 (0.00003) | 0.285 (0.006) | 0.89 (0.047) | 0.24 (0.01) |
at Γ ~11.5 | 0.416 (0.008) | 0.053 (0.0004) | 0.034 (0.001) | 0.0006 (0.00003) | 0.469 (0.008) | 0.89 (0.032) | 0.40 (0.01) |
at Γ ~22.5 | 0.560 (0.008) | 0.061 (0.0004) | 0.046 (0.001) | 0.0007 (0.00003) | 0.621 (0.01) | 0.90 (0.019) | 0.53 (0.01) |
The standard error for each parameter as reported by the nonlinear least-squares fitting procedure is included in parentheses. From previous work (36), the relative error in G(∑fr) is seen to vary from ±5% to ±15%. It is assumed that in the absence of geminate ion recombination and cross combination reactions, the initial yield of radicals is Ginitial(fr) ~ 1.18 μmol/J (56).