Activation analysis standard error

FIGURE 11.3 One-way ANOVA (analysis of variance). One-way analysis of variance of basal rates of metabolism in melanophores (as measured by spontaneous dispersion of pigment due to G,.-protein activation) for four experiments. Cells were transiently transfected with cDNA for human calcitonin receptor (8 j-ig/ml) on four separate occasions to induce constitutive receptor activity. The means of the four basal readings for the cells for each experiment (see Table 11.4) are shown in the histogram (with standard errors). The one-way analysis of variance is used to determine whether there is a significant effect of test occasion (any one of the four experiments is different with respect to level of constitutive activity). 

Methods were described for diminishing the systematic errors in Pb activation analysis, stemming from the variable isotopic composition of Pb. Results with ICP-AES and ICP-MS were taken as standards for comparison106. 

All samples were dried for 72 hours at 80°C, and dry weights were calculated. Dried samples were milled to spectrometrically measure the specific activity of i Cs. The standard error of specific activity was in the range 10-20%. Statistical analysis used the software package MS Excel. 

Recently, Gasteiger et al. [59] reported several models to predict human oral bioavailability using Hou and Wang s data set. A set of ADRIANA.Code and Cerius2 descriptors were calculated, and MLR analysis was performed. The best linear model had r2 of 0.18 and RMSD of 31.15. When a set of subsets was cherry-picked so that each subset had either a common functional group or a similar pharmacological activity, the r2 values were improved and RMSD values dropped. But the performance of those models was still not satisfactory the standard errors were above 20.0 and r2 was lower than 0.6. 

For each parameter, means and standard error calculated, an analysis of variance is performed and the appropriate tests of significance are applied. The mean values of each parameter of the treated groups are compared with the values of the vehicle control group. It is important to compare the results with reference to their use for the rat strain commonly-used in the Laboratory. For many studies it may be advisable to include groups treated with reference compounds of established endocrine activity. 

While high sensitivity has been obtained in the examination of pure materials, a far more rigorous test of the activation method is found in its application to materials of a more complex matrix. Emission and X-ray spectrometry and direct spark source mass spectrometry are all restricted by the lack of suitable standards when applied to materials of complex composition. Provided that precautions are taken to avoid self-shielding errors radioactivation is largely independent of the nature of the matrix material. It is this advantage which has enabled activation analysis to prove such an invaluable tool in geochemistry. 

Fig. 8.6. Comparison of the uptake within liver lesions in pre-therapeutic MAA SPECT images and in post-therapeutic bremsstrahlung SPECT. The analysis is confined to metabolically active liver lesions as determined from F-FDG PET/CT scanning. Values are given as mean standard error. Higher uptake of lesions in pre-therapeutic MAA scintigraphy correlates with higher SIR-Spheres deposition, but this relation does not reach the level of significance...

For the SDT data, we considered only mass loss for kinetic analysis. Instability of the DTA baseline meant that results were inconclusive as to whether the mass loss corresponds to an endothermic or exothermic reaction or some combination thereof Kissinger s method yielded A = 2.19x1013 s-1 and E = 173.5 kj/ mol, with a standard error of 8.7 kj/mol on the activation energy. The Freidman parameters are shown in Figure 3 and are approximately equal to the Kissinger value. The AKTS code with its baseline optimization feature has less noise at low conversion, but the two programs agree very well overall. 

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