Time Evolution Of Nonequilibrium Photoexcited Plasma In Polar Semiconductors

The nonequilibrium thermodynamics and kinetics of evolution of relaxation processes in polar semiconductors under high levels of optical excitation is studied. This is done using a first-principles theory that allows for the determination of the nonlinear transport equations which describe the irreversible processes that develop in the media in typical pump-probe experiments. Numerical calculations are presented which permit a comprehensive discussion of measurements of ultrafast-time-resolved optical spectra of GaAs. © 1983 The American Physical Society.27127563757

Ultrafast kinetics of evolution of optical phonons in a photoinjected highly excited plasma in semiconductors

We consider the ultrafast kinetics of evolution of optical phonons in a photoinjected highly excited plasma in semiconductors. The state of the nonequilibrium ('hot') phonon system is described in terms of the concept of a nonequilibrium temperature, referred to as quasitemperature, per mode, which can be experimentally characterized and measured. The phonon emission time shows that optical phonons are preferentially produced, well in excess of equilibrium, in a reduced off-center region of the Brillouin zone. The phonons in this region are responsible for the phenomenon referred to as 'hot-phonon temperature overshoot.' Most of the phonons, namely, those outside such a region, are only weakly to moderately excited, and mutual thermalization of the nonequilibrium carriers and optical phonons follows, typically, in the tenfold picosecond scale. All these results are influenced by the experimental conditions, which we discuss on the basis of calculations specialized for GaAs. Comparison with experimental data is presented.5416113111131

DIFFUSION OF PHOTOINJECTED CARRIERS IN PLASMA IN NONEQUILIBRIUM SEMICONDUCTORS

We consider effects of diffusion in the photogenerated carrier system in highly photoexcited polar semiconductors. We develop a quantum quasihydrodynamic description of the system based on the nonequilibrium statistical operator formalism. We derive a generalized Fick's diffusion equation for the charge density of the carriers, with the ambipolar diffusion coefficient obtained at the microscopic level and depending on the evolving macroscopic (nonequilibriium thermodynamic) state of the sample. A detailed numerical calculation for the case of GaAs is done, obtaining good agreement with experimental data.4815108731088

NONLINEAR TRANSPORT IN PHOTOEXCITED PLASMA IN SEMICONDUCTORS - NONOHMIC MOBILITY AND A GENERALIZED EINSTEIN RELATION

Resorting to a theory of responses to thermal and mechanical perturbations, based on statistical irreversible thermodynamics for systems arbitrarily away from equilibrium, we obtain the diffusion and mobility coefficients in a highly photoexcited plasma in semiconductors in the presence of an electric field. They are dependent on the evolution of the nonequilibrium thermodynamic state of the system. From these transport coefficients we derived a generalized Einstein relation for ultrafast transient regimes and for non-Ohmic conditions. In all cases this generalized Einstein law acquires values that are field dependent and larger than those in its original form only valid in steady-state conditions and the limit of weak fields. Numerical results appropriate for the case of a GaAs sample are presented.5219139361394

Promotion of Hendra virus replication by microRNA 146a

Hendra virus is a highly pathogenic zoonotic paramyxovirus in the genus Henipavirus. Thirty-nine outbreaks of Hendra virus have been reported since its initial identification in Queensland, Australia, resulting in seven human infections and four fatalities. Little is known about cellular host factors impacting Hendra virus replication. In this work, we demonstrate that Hendra virus makes use of a microRNA (miRNA) designated miR-146a, an NF-κB-responsive miRNA upregulated by several innate immune ligands, to favor its replication. miR-146a is elevated in the blood of ferrets and horses infected with Hendra virus and is upregulated by Hendra virus in human cells in vitro. Blocking miR-146a reduces Hendra virus replication in vitro, suggesting a role for this miRNA in Hendra virus replication. In silico analysis of miR-146a targets identified ring finger protein (RNF)11, a member of the A20 ubiquitin editing complex that negatively regulates NF-κB activity, as a novel component of Hendra virus replication. RNA interference-mediated silencing of RNF11 promotes Hendra virus replication in vitro, suggesting that increased NF-κB activity aids Hendra virus replication. Furthermore, overexpression of the IκB superrepressor inhibits Hendra virus replication. These studies are the first to demonstrate a host miRNA response to Hendra virus infection and suggest an important role for host miRNAs in Hendra virus disease

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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