The objective of this study was to investigate the electrical impedance properties of rat lung and other tissues ex vivo using Electrical Impedance Spectroscopy. Rat lungs (both electroporated and naïve (untreated)), and mesenteric vessels (naïve) were harvested from male Sprague-Dawley rats; their electrical impedance were measured using a Solartron 1290 impedance analyzer. Mouse lung and heart samples (naïve) were also studied. The resistance (Real Z, ohm) and the reactance (Im Z, negative ohm)) magnitudes and hence the Cole-Cole (Real Z versus Im Z) plots are different for the electroporated lung and the naive lung. The results confirm the close relationship between the structure and the functional characteristic. These also vary for the different biological tissues studied. The impedance values were higher at low frequencies compared to those at high frequencies. This study is of practical interest for biological applications of electrical pulses, such as electroporation, whose efficacy depends on cell type and its electrical impedance characteristics.

The most suitable candidates for ECT were patients with few and small metastases on the lower limb treated with multiple electrode applications and ECT cycles.

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Aging and degradation of 345 kV ethylene propylene diene monomer EPDM transmission line insulators removed from service is presented. These suspension type insulators were installed in a New Hampshire coastal area in 1995 and were removed in 2000 after unexplained outages in that structure. The purpose of this paper is to better understand the aging and degradation mechanisms of EPDM insulators in service. The insulators showed severe chalking and discoloration and partial loss of hydrophobicity on the side facing the sun. The surface structural changes were studied in detail using advanced surface analysis techniques, such as ( ) attenuated total reflection Fourier Transform Infrared Spectroscopy ATR-FTIR , ( ) Scanning Electron Microscopy SEM and X-Ray Photoelectron Spectroscopy ( ) XPS . For the first time, the significant differences in surface properties between ( ) ( ) the chalkedr r r r rdiscolored white and the other surfaces dark were studied quanti-( ) tatively. The Fourier Transform infrared FTIR absorption spectra showed a significant decomposition of the CH groups of the white surface, elucidating the effect of photo-oxidation on the EPDM polymer. The SEM micrographs showed the cracking of the surfaces. The XPS spectra showed the formation of various polar carboxyl groups and the presence of high surface energy compounds, such as silica, and silicates. This study provided valuable basic information on the changes in the surface properties of EPDM insulators during service in a coastal environment. Index Terms -EPDM transmission line insulators, aging, degradation, FTIR, SEM, XPS.1070-9878r r r r r04r r r r r$20.00 ᮊ 2004 IEEE 348 1070-9878r r r r r04r r r r r$20.00 ᮊ 2004 IEEE 1070-9878r r r r r04r r r r r$20.00 ᮊ 2004 IEEE