Conductance

About: Conductance is a research topic. Over the lifetime, 8088 publications have been published within this topic receiving 235961 citations.

Spin mixing conductance at a well-controlled platinum/yttrium iron garnet interface

Abstract: A platinum (Pt)/yttrium iron garnet (YIG) bilayer system with a well-controlled interface has been developed; spin mixing conductance at the Pt/YIG interface has been studied. A clear interface with good crystal perfection is experimentally demonstrated to be one of the important factors for an ultimate spin mixing conductance. The spin mixing conductance is obtained to be 1.3 × 1018 m–2 at the well-controlled Pt/YIG interface, which is close to a theoretical prediction.

Combined effect of disorder and interaction on the conductance of a one-dimensional fermion system

Abstract: It is shown that the conductance of an interacting one-dimensional system may be expressed in the form of a Landauer formula. An insulator-ideal-conductor transition is found as the interaction is varied at zero temperature.

A pH-sensitive and voltage-dependent proton conductance in the plasma membrane of macrophages.

Abstract: Phagocytes generate large amounts of metabolic acid during activation. Therefore, the presence of a conductive pathway capable of H+ extrusion has been suggested (Henderson, L. M., J. B. Chappell, and O. T. G. Jones. 1987. Biochemical Journal. 246:325-329). In this report, electrophysiological and fluorimetric methods were used to probe the existence of a H+ conductance in murine peritoneal macrophages. In suspended cells, recovery of the cytosolic pH (pHi) from an acid-load in Na+ and HCO3(-)-free medium was detectable in depolarizing but not in hyperpolarizing media. The rate of alkalinization was potentiated by the rheogenic ionophore valinomycin. These findings are consistent with the existence of a conductive H+ (equivalent) pathway. This notion was confirmed by patch-clamping and fluorescence ratio measurements of single adherent cells. When voltage was clamped in the whole-cell configuration, depolarizing pulses induced a sizable outward current which was accompanied by cytosolic alkalinization. Several lines of evidence indicate that H+ (equivalents) carry this current: (a) the conductance was unaffected by substitution of the major ionic constituents of the intra-and/or extracellular media, (b) the reversal potential of the tail currents approached the H+ equilibrium potential; and (c) the voltage-induced currents and pHi changes were both Zn2+ sensitive and had similar time course and potential dependence. The peak whole-cell current displayed marked outward rectification and was exquisitely H+ selective. At constant voltage, the H+ permeability was increased by lowering pHi but was inhibited by extracellular acidification. Together with the voltage dependence of the conductance, these features ensure that H+ extrusion can occur during activation, while potentially deleterious acid uptake is precluded. The properties of the conductance appear ideally suited for pHi regulation during phagocyte activation, because these cells undergo a sustained depolarization and an incipient acidification when stimulated. Comparison of the magnitude of the current with the amount of metabolic acid generated during macrophage activation indicates that the conductance is sufficiently large to contribute to the H+ extrusion required for maintenance of pHi.

Near-perfect conduction through a ferrocene-based molecular wire

Abstract: Here we describe the design, single-molecule transport measurements, and theoretical modeling of a ferrocene-based organometallic molecular wire, whose bias-dependent conductance shows a clear Lorentzian form with magnitude exceeding 70% of the conductance quantum ${G}_{0}$. We attribute this unprecedented level of single-molecule conductance to a manifestation of the low-lying molecular resonance and extended orbital network long predicted for a conjugated organic system. A similar-in-length, all-organic conjugated phenylethynyl oligomer molecular framework shows much lower conductance.

Unique Conductance, Gating, and Selective Permeability Properties of Gap Junction Channels Formed by Connexin40

Abstract: Connexin40 is selectively expressed in specialized cardiac conduction (nodal and His-Purkinje) tissues and the atrium, yet the channel properties formed by this gap junction protein have not been investigated. The conductance, gating, and selective permeability of rat connexin40 (Cx40) gap junction channels between pairs of Cx40-transfected mouse neuroblastoma (N2A) cells in culture were studied by using dual whole-cell voltage-clamp techniques. The macroscopic steady state junctional conductance gating was dependent on transjunctional voltage with a Boltzmann half-inactivation voltage of ±50 mV, a residual voltage-insensitive normalized junctional conductance of 35% of maximum, and a gating charge valence of 3. In the presence of 120 mmol/L potassium glutamate, the slope conductance of single rat Cx40 gap junction channels measured 158±2 pS (n=4). Lower conductance states equal to 21% to 48% of the main open-state conductance were also occasionally observed in two of the four cell pairs. Multichannel open probabilities were found to be heterogeneous. Ion substitution and dye transfer experiments were performed to determine the relative chloride/potassium conductance and dye permeability of anionic fluorescein derivatives in rat Cx40 channels. The rat Cx40 channel had a maximum conductance of 180±18 pS (n=3) in 120 mmol/L KCl and a detectable chloride permeability of 0.29 relative to potassium, indicating some selectivity for cations over anions. Cx40 gap junctions were permeable to 2′,7′-dichlorofluorescein (diCl-F) and also to the more polar 6-carboxyfluorescein dye; however, diCl-F dye transfer was not observed to increase with increasing junctional conductance.