16 research outputs found
Classical 5D fields generated by a uniformly accelerated point source
Gauge fields associated with the manifestly covariant dynamics of particles
in spacetime are five-dimensional. In this paper we explore the old
problem of fields generated by a source undergoing hyperbolic motion in this
framework. The 5D fields are computed numerically using absolute time
-retarded Green-functions, and qualitatively compared with Maxwell fields
generated by the same motion. We find that although the zero mode of all fields
coincides with the corresponding Maxwell problem, the non-zero mode should
affect, through the Lorentz force, the observed motion of test particles.Comment: 36 pages, 8 figure
Adiabatic Pair Creation
We give here the proof that pair creation in a time dependent potentials is
possible. It happens with probability one if the potential changes
adiabatically in time and becomes overcritical, that is when an eigenvalue
enters the upper spectral continuum. The potential may be assumed to be zero at
large negative and positive times. The rigorous treatment of this effect has
been lacking since the pioneering work of Beck, Steinwedel and Suessmann in
1963 and Gershtein and Zeldovich in 1970.Comment: 53 pages, 1 figure. Editorial changes on page 22 f
A study of the photodynamic efficiencies of some eye lens constituents
We have studied the photochemical quantum yields of singlet oxygen production (using the RNO bleaching method) and superoxide production (using the EPR-spin trapping method and the SOD-inhibitable ferricytochrome c reduction spectral assay) of kynurenine (Ky), N-formylkynurenine (NFK), 3-hydroxykynurenine (3HK), kynurenic acid (KUA), and the flavins, riboflavin (RF) and flavin mononucleotide (FMN). Such a study of the photodynamic efficiencies is important since these compounds appear endogenously in the eye. The singlet oxygen quantum yields of the flavins and KUA are high, while Ky and 3HK generate no detectable amounts of singlet oxygen. The superoxide quantum yields of the sensitizers are low compared to their singlet oxygen, and Ky and 3HK produce no detectable amounts of superoxide. The production of the superoxide radical is enhanced in the presence of electron donor molecules such as EDTA and NADH. These results suggest that the production of oxyradicals in the lens may be modulated by the presence of endogenous electron donor molecules such as the coenzymes NADH and NADPH, which are present in significant amounts in some lenses. They also suggest that Ky and 3HK, which are known to be present in aged lenses, might play a protective rather than a deleterious role in the eye