Landauer Theory, Inelastic Scattering and Electron Transport in Molecular Wires

In this paper we address the topic of inelastic electron scattering in mesoscopic quantum transport. For systems where only elastic scattering is present, Landauer theory provides an adequate description of transport that relates the electronic current to single-particle transmission and reflection probabilities. A formalism proposed recently by Bonca and Trugman facilitates the calculation of the one-electron transmission and reflection probabilities for inelastic processes in mesoscopic conductors connected to one-dimensional ideal leads. Building on their work, we have developed a self-consistent procedure for the evaluation of the non-equilibrium electron distributions in ideal leads connecting such mesoscopic conductors to electron reservoirs at finite temperatures and voltages. We evaluate the net electronic current flowing through the mesoscopic device by utilizing these non-equilibrium distributions. Our approach is a generalization of Landauer theory that takes account of the Pauli exclusion principle for the various competing elastic and inelastic processes while satisfying the requirement of particle conservation. As an application we examine the influence of elastic and inelastic scattering on conduction through a two site molecular wire with longitudinal phonons using the Su-Schrieffer-Heeger model of electron-phonon coupling.Comment: 25 pages, 8 figure

Recent and Future Advances in the Treatment of Status Epilepticus

Status epilepticus (SE) is one of the most frequent neurological emergencies with an incidence of 20/100,000 per year and a mortality between 3% and 40% depending on etiology, age, SE type and duration. Generalized convulsive forms of SE (GTCSE), in particular, require aggressive treatment. Presently, only 55–80% of cases of GTCSE are controlled by initial therapy. Therefore, there is a need for new options for the treatment of SE. Here we review the current standard treatment including recent advances and provide a summary of preclinical and clinical data regarding treatment options which may become available in the near future. The initial treatment of SE usually consists of a benzodiazepine (preferably lorazepam 0.1 mg/kg) followed by phenytoin or fosphenytoin or valproic acid (where approved for SE therapy). With intravenous formulations of levetiracetam, available since 2006, and lacosamide, which is expected for autumn of 2008, new treatment options have become available, that should be evaluated in prospective controlled trials. If SE remains refractory, the induction of general anaesthesia using propofol, midazolam, thiopental, or pentobarbital is warranted in GTCSE

DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy

Funding Information: This material is based upon work supported by the US Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Awards DE-FC02-04ER54698 and DE-AC52-07NA27344. Publisher Copyright: © 2022 IAEA, Vienna.DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.Peer reviewe