Accession Number : ADA302761

Title :   Role of Counterions in the Gigahertz Relaxation of Wet DNA,

Descriptive Note : Rept. for 1 Feb 87-31 Jan 91,

Corporate Author : VANDERBILT UNIV NASHVILLE TN

Personal Author(s) : Edwards, Glenn ; Ying, Guangtao ; Tribble, Jerri

PDF Url : ADA302761

Report Date : 31 JAN 1991

Pagination or Media Count : 17

Abstract : We have measured the dielectric properties of concentrated solutions and gels (<30 mg/ml) of random-sequenced DNA from E.coli in the 400 MHz to 26 GHz range. Two Debye-type relaxations are evident, one with a relaxation time near 9 Ps and attributable to the classical Debye relaxation of water. More noteworthy is a second relaxation process with a characteristic time in the 20 to 200 Ps range, i.e. a relaxation frequency in the 0.8 to 8 GHz range, depending upon the species of the counterions and the temperature. The slower relaxation process has an enthalpy of 3.3 kcal/mol and is accounted for by a counter-ion-based relaxation process. These experimental results are considered in terms of two models from polyelectrolyte theory, one by Oosawa and Wyllie and the other by Manning, and we propose that different ion-based relaxation mechanisms dominate in different hydration regimes.

Descriptors :   *RANDOM VARIABLES, *DEOXYRIBONUCLEIC ACIDS, *DIELECTRIC PROPERTIES, *PSEUDO RANDOM SEQUENCES, FREQUENCY, SOLUTIONS(MIXTURES), WATER, POLYELECTROLYTES, THEORY, FREE ELECTRON LASERS, RELAXATION, GELS, HYDRATION, RELAXATION(PHYSIOLOGY).

Subject Categories : Biochemistry
      Medicine and Medical Research
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE