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The modifying effects of the products of the equimolar addition of DL-alanine and m-alanyl-oc-alanine to fullerene CW on the structure and permeability of the lipid bilayer of phosphatidylcholine liposomes has been studied using the luminescence probe technique. It is shown that these water soluble amino acid and dipeptide derivatives of fullerene (C,-AD) are quenchers of pyrene fluorescence and erythrosine phosphorescence of in both a water solution and liposomes. To study the permeability of the lipid hilayer a procedure based on the triplet probe technique has been developed. It has been found that the &-AD derivatives under study are able to localize inside the artificial membrane, to penetrate into the liposomes through the lipid hilayer and to perform activated transmembrane transport of bivalent metal ions.

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The multi-electrode current source (MECS) interstitial hyperthermia system, which is used for treatment of cancer, employs segmented electrodes inserted in plastic tubes implanted in the treatment volume. The mean power deposition of the individual electrodes is controlled by varying the duty cycle of the RF signal applied to the electrodes, using thermocouples inside the electrodes for thermometry.A non-zero loss angle results in self-heating of the catheter. The thermal influence of selfheating was investigated and an analysis of the measurement of temperatures inside the catheter during and after heating is presented. Analytical models and a high-resolution numerical model were used for the calculation of steady state and transient distributions, respectively. The model results are compared with experimental data obtained in a muscle equivalent phantom.Results indicate that there is no difference between temperature inside and outside the catheter when using lossless catheter materials (e.g. PE and PTFE). Self-heating in the catheter wall has an adverse effect on the uniformity of the stationary temperature distribution and the reliability of temperature measurement with internal thermometry. These problems remain within acceptable limits for mildly lossy materials; the difference between the temperature inside and outside is only 6% when using low-loss Nylon.Analysis of the thermal decay after power-off shows that low-loss materials allow more time to obtain an accurate estimate of the tissue temperature at the catheter wall during power-on. This effect is enhanced by the presence of minute air layers in the applicator.Distortion of temperature gradients along the catheter was also investigated. Key factors are the thermal conduction across the catheter wall, and especially the presence of minute layers of air between consecutive layers of the probe. The distortion extends less than two millimetres, which is acceptable.The simulation results are compatible with measurements in phantoms and show that, if the proper choice of materials is made, the MECS applicator answers our expectations and that the temperature measurement inside the catheter can be used for direct feedback treatment control.