Long-time tails in a one component plasma

Oscillatory long-time tails are obtained for the shear viscosity of a one component plasma from a microscopic theory. The non-analytic expansion in k² of the shear mode is also given.     

Kinetic Theory of a Weakly‐Nonideal Spatially Nonuniform Polarizable Plasma

A nonmarkovian and nonlocal kinetic equation, which is a generalization of the (nonlinear) Balescu‐Lenard equation, is derived for a weakly nonuniform multicomponent polarizable plasma. A specific expansion of the plasma resolvent, which allow to separate the dymamic, kinetic and hydrodynamic scales, is proposed. Explicit expressions of the collision integral and of the nonequilibrium pair correlation function are given in an approximation which take into account the effect of patial and temporal nonlocality a well as of the polarization. Balance equation for the momentum and energy densitie are calculated in the first order in nonlocality, and potential contributions to the fluxes due to polarization are obtained.     

A comparative repair study of thymine- and uracil-photodimers with model compounds and a photolyase repair enzyme

Cyclobutane uridine and thymidine dimers with cis-syn-structure are DNA lesions, which are efficiently repaired in many species by DNA photolyases. The essential step of the repair reaction is a light driven electron transfer from a reduced FAD cofactor (FADH ) to the dimer lesion, which splits spontaneously into the monomers. Repair studies with UV-light damaged DNA revealed significant rate differences for the various dimer lesions. In particular the effect of the almost eclipsed positioned methyl groups at the thymidine cyclobutane dimer moiety on the splitting rates is unknown. In order to investigate the cleavage vulnerability of thymine and uracil cyclobutane photodimers outside the protein environment, two model compounds, containing a thymine or a uracil dimer and a covalently connected flavin, were prepared and comparatively investigated. Cleavage investigations under internal competition conditions revealed, in contrast to all previous findings, faster repair of the sterically less encumbered uracil dimer. Stereoelectronic effects are offered as a possible explanation. Ab initio calculations and X-ray crystal structure data reveal a different cyclobutane ring pucker of the uracil dimer, which leads to a better overlap of the pi*-C(4)-O(4)-orbital with the sigma*-C(5)-C(5')-orbital. Enzymatic studies with a DNA photolyase (A. nidulans) and oligonucleotides, which contain either a uridine or a thymidine dimer analogue, showed comparable repair efficiencies for both dimer lesions. Under internal competition conditions significantly faster repair of uridine dimers is observed.     

On the shear viscosity of a strongly coupled one-component plasma

It is shown on the basis of a microscopic theory that the shear viscosity of a one-component plasma exhibits a minimum as a function of temperature.     

Long-time behavior of the nonlocal shear viscosity of a one-component plasma: A microscopic approach

The nonlocal shear viscosity(t) of a classical one-component plasma is shown to have anoscillatory long-time tail. This result is obtained on the basis of amicroscopic theory which does not rely on expansions in a small parameter such as the plasma expansion parameter. Our major approximation is the restriction to the coupling oftwo hydrodynamic propagators in the computation of the long-time behavior of the transport matrix. The Coulomb divergence is correctly accounted for, while the nonanalyticities of both the plasma parameter and gradient expansions are discussed at the level of the kinetic as well as the hydrodynamic equations.