Results 1 - 10 of 99584
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[en] A new chemiluminescence (CL) method is proposed for the determination of phentolamine, which is based on the reaction between studied drug and Cerium(IV) (Ce(IV)) in a nitric acid medium and measurement of the CL intensity produced by rhodamine 6G used as a sensitizer. In the optimum conditions, CL intensities are proportional to concentrations of the studied drug over the range 1x10-9-1x10-6 g/ml with a detection limit of 4x10-10 g/ml. The relative standard deviation (R.S.D.) is 3.4% for 1x10-7 g/ml phentolamine (n=11). The method has been applied to the determination of studied drug in injections and biological fluids with satisfactory results
[en] PARP inhibitors are currently evaluated in combination with radiotherapy and/or chemotherapy. As sensitizers, PARP inhibitors are active at very low concentrations therefore requiring highly sensitive pharmacodynamic (PD) assays. Current clinical PD-assays partly fail to provide such sensitivities. The aim of our study was to enable sensitive PD evaluation of PARP inhibitors for clinical sensitizer development.
[en] When reporting best estimates as measurement results, systematic influences near the natural limit are introduced that originate not only in the possible inconsistency of the analytical procedure but also in the conversion of the primary measurement results to best estimates. It has been shown that the probability density distribution resembling shifting of values observed in the unfeasible region to the limit of the feasible range (the natural limit) introduces a smaller systematic influence than the Bayesian posterior, resembling censoring with repetition of the measurements that result in observed values in the unfeasible region. The drawback that the uncertainty intervals calculated with the Bayesian posterior do not encompass the natural limit and may not encompass the observed value, although it lies within the feasible region, is avoided by using the probability density distribution resembling shifting. Therefore, such best estimates introduce a smaller systematic influence into the measurement results and are better suited as inputs for subsequent analyses. (author)
[en] Mixture models are receiving considerable significance in the last years. Practical situations in reliability and survival analysis may be addressed by using mixture models. When making inferences on them, besides the estimates of the parameters, a sensitivity analysis is necessary. In this paper, a general technique to estimate local prior sensitivities in finite mixtures of distributions from natural exponential families having quadratic variance function (NEF-QVF) is proposed. Those families include some distributions of wide use in reliability theory. An advantage of this method is that it allows a direct implementation of the sensitivity measure estimates and their errors. In addition, the samples that are drawn to estimate the parameters in the mixture model are re-used to estimate the sensitivity measures and their errors. An illustrative application based on insulating fluid failure data is shown.
[en] Highlights: → The sensitivity and uncertainty analyses were performed to comprehend the reliability of the XT-ADS neutronic design. → The uncertainties deduced from the covariance data for the XT-ADS criticality were 0.94%, 1.9% and 1.1% by the SCALE 44-group, TENDL-2009 and JENDL-3.3 data, respectively. → When the target accuracy of 0.3%Δk for the criticality was considered, the uncertainties did not satisfy it. → To achieve this accuracy, the uncertainties should be improved by experiments under an adequate condition. - Abstract: The XT-ADS, an accelerator-driven system for an experimental demonstration, has been investigated in the framework of IP EUROTRANS FP6 project. In this study, the sensitivity and uncertainty analyses were performed to comprehend the reliability of the XT-ADS neutronic design. For the sensitivity analysis, it was found that the sensitivity coefficients were significantly different by changing the geometry models and calculation codes. For the uncertainty analysis, it was confirmed that the uncertainties deduced from the covariance data varied significantly by changing them. The uncertainties deduced from the covariance data for the XT-ADS criticality were 0.94%, 1.9% and 1.1% by the SCALE 44-group, TENDL-2009 and JENDL-3.3 data, respectively. When the target accuracy of 0.3%Δk for the criticality was considered, the uncertainties did not satisfy it. To achieve this accuracy, the uncertainties should be improved by experiments under an adequate condition.
[en] The unique action of paclitaxel to stabilise microtubules and block cells at the radiosensitive G2/M phase of the cell cycle, suggests it may sensitise tumours to radiotherapy. Since the use of paclitaxel may be compromised in drug resistant tumours due to drug efflux by P-glycoprotein, the ability of paclitaxel to sensitise multidrug resistant cells to radiation was examined in HL60 cells and a multidrug resistant subline, H/E8, developed by intermittent treatment with epirubicin. Poster 201. (author)
[en] Equations are derived that connect the mass of a representative sample and such components of the total variance which characterize the dispersion of the results of neutron activation analysis (NAA), such as the variances of nonuniformity and replicate reproducibility. A method is proposed to estimate the minimum mass of a representative sample in the NAA of nonhomogeneous materials
[en] Neurodegenerative diseases of the central motor system often lead to discrete but functionally important parenchymal abnormalities in various parts of the brain. MRI is the most sensitive imaging method to detect these abnormalities. Various neurodegenerative diseases are presented with their clinical symptoms and MRI findings. Criteria for differential diagnosis are provided as well. (orig.)