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Title: The effect of magnetic field on the dielectric properties of DNA
Author: Owen, R. Brynmor
ISNI:       0000 0004 2736 6256
Awarding Body: Prifysgol Bangor University
Current Institution: Bangor University
Date of Award: 2012
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Previous workers have shown that high magnetic fields cause morphological changes in DNA at high concentration where it exists as the liquid crystal cholesteric phase. The aim of the present work was to identify corresponding changes in the dielectric properties of DNA in the frequency range 20 Hz to 300 kHz, at lower magnetic field intensity and lower concentrations. Investigations were carried out with DNA solution on interdigitated electrodes, where the magnetic field was applied perpendicular to the electric field. Evidence was found of reversible changes in the dielectric properties caused by magnetic fields lower than 0.7 Tesla at high concentrations (rv 170 mg/ml). Using planar electrodes, where the magnetic field was applied parallel to the electric field, reversible changes in dielectric properties due to magnetic fields of lower than 0.7 Tesla were found in DNA solutions at lower concentrations (25 - 100 mg/rnl). Replacement of the sodium in the DNA with other cations by dialysis produced similar results, though the frequencies of the responses also varied with the cations used. A method was developed using Matlab's Genetic Algorithm toolbox to analyse the difference between loss spectra caused by changes in one dispersion. The method was able to extract the parameters of the dispersion before and after application of the magnetic field. Changes in these parameters with concentration, temperature, additional sodium chloride, and applied a.c.voltage are reported. Changes with temperature indicate that an Arrhenius-type process is responsible for the dispersion. Evidence was presented that the dispersion found to be susceptible to magnetic field was caused by relaxation of the counter-ions in the condensed phase surrounding the DNA chain.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available