The normality of the data was evaluated using the
Kolmogorov-Smirnov test. Statistical comparisons between
the groups were done using Student’s two-tailed
t-test. Differences between exposure times were analyzed
using the non-parametric two-tailed Kruskal-Wallis test
followed by Dunns test for multiple comparisons. The critical
level for rejection of the null hypothesis was p < 0.05.