Biomedical Engineering Reference
In-Depth Information
variances based on position in the sequence for each of four cases: For nickel, binding to the
native column comparing positions 1 and 3, and positions 2 and 3;. Also for cadmium
exposed to the modified column comparing positions 1 and 3, and positions 2 and 3. These
values again suggested greater inhomogeneity in the impact of the chemical modification
procedure on the sites involved in the binding of these metal ions.
1 vs. 2 1 vs. 3 2 vs. 3
T Cd native 0.739 0.671 0.985
T Ni native 0.196 0.462 0.338
T Zn native 0.380 0.707 0.596
T Cd modified 0.241 0.195 0.912
T Ni modified 0.699 0.686 0.955
T Zn modified 0.567 0.182 0.428
F Cd native 0.119 0.253 0.296
F Ni native 0.407 0.035 0.022
F Zn native 0.399 0.485 0.413
F Cd modified 0.400 0.025 0.041
F Ni modified 0.223 0.382 0.320
F Zn modified 0.476 0.397 0.421
Table 4. Comparing influent metal bound at each position. T values are statistical probability
that the mean metal bound at each position in sequence are the same. F values are statistical
probability that their variances are the same.
Tables 5a-c provide a closer look at metal position by considering the history of metal
exposure as well as position of each metal ion in the sequence. The t-values for all three
metals indicated no statistical difference as a result of metal exposure history to the influent
metal bound for either the native or modified biomaterial. The F-values again suggest
statistical differences in the variances in Ni
2+
binding based on exposure history. The
modified biomaterial showed a difference in the variances for the comparison of the
sequences CdZnNi with ZnCdNi, and CdNi with CdZnNi. Comparatively larger relative
standard deviations (RSDs) were calculated for the sequences CdNi and ZnCdNi relative to
that for the CdZnNi exposure sequence. A probable difference in variances for the
comparison of CdNi with CdZnNi, and CdNi with ZnCdNi was also observed for the native
material. Under these conditions, CdNi exhibited comparatively large standard deviation
relative to those of the other two conditions.
3.3.3 Binding site matrix analysis
Traditional statistical analysis of the metal ion binding data suggested that the chemical
modification of the
D. innoxia
material decreased the number of binding sites significantly,
thus reducing metal binding capacities for the esterified biomaterial. Additionally,
statistically significant changes in the Ni
2+
binding variability suggested non-uniform
changes in metal-specific sites that resulted from the esterification reaction. In an effort to
extract more information about the binding behavior of the biomaterial towards these three
metals, a secondary method of data analysis was undertaken.
