Analysis of Genotoxicity Data in a Regulatory Context

Abstract

Analytical methods for regulatory tests usually must be defined before testing. To take this into account and to minimise equivocal interpretations, a sequential strategy is recommended. Assay validity must be verified and results then classed as clearly negative, clearly positive, or uncertain based on historical data. Where there is uncertainty, standard parametric or non-parametric statistical methods should be used with appropriate corrections to assess the significance. The biological importance of statistically significant data should then be evaluated using historical data.

Three Dimensional Picture of the Local Structure of 1,4-Polybutadiene from a Complete Atomistic Model and Neutron Scattering Data

“…The rest of the diffraction pattern is dominated by scattering between atoms joined by covalent bonds and the changes in that region cannot be directly observed from the relative changes in the pattern. By performing nonlinear peak fitting using a Gaussian function, 22 the relative position and width of the main scattering peak as a function of temperature can be deduced and the results are presented in Figures 2 and 3. From these figures the crossover between the liquid and glassy regime can be clearly seen and the intersection of the two fitting lines to the experimental data can be associated with the glass transition temperature.…”

“…The calculated function is in principle available as a continuous function. However, due to the need for a speedy computation process to allow many models to be considered, we calculate the structure factor by fast Fourier transform techniques 22 which yield a discrete set of calculation points. Furthermore, the interatomic distances were binned; thus, the χ 2 relationship is a calculation between two discrete and not continuous functions.…”