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Abstract: The electrochemical performance of a composite of nano-Si powder and a pyrolytic carbon of polyvinyl chloride (PVC) with carbon nanofiber (CNF) was examined as an anode for lithium-ion batteries. CNF was incorporated into the composite by two methods; direct mixing of CNF with the nano-Si powder coated with carbon produced by pyrolysis of PVC (referred to as Si/C/CNF-1) and mixing of CNF, nano-Si powder, and PVC with subsequent firing (referred to as Si/C/CNF-2). The external Brunauer–Emmett–Teller (BET) surface area of Si/C/CNF-1 was comparable to that of Si/C/CNF-2. The micropore BET surface area of Si/C/CNF-2 (73.86m2 g−1) was extremely higher than that of Si/C/CNF-1 (0.74m2 g−1). The composites prepared by both methods exhibited high capacity and excellent cycling stability for lithium insertion and extraction. A capacity of more than 900mAhg−1 was maintained after 30 cycles. The coulombic efficiency of the first cycle for Si/C/CNF-1 was as low as 53%, compared with 73% for Si/C/CNF-2. Impedance analysis of cells containing these anode materials suggested that the charge transfer resistance for Si/C/CNF-1 was not changed by cycling, but that Si/C/CNF-2 had high charge transfer resistance after cycling. A composite electrode prepared by mixing Si/C/CNF-2 and CNF exhibited a high reversible capacity at high rate, excellent cycling performance, and a high coulombic efficiency during the first lithium insertion and extraction cycles. [Copyright &y& Elsevier]

High lithium ion conductivity solid electrolytes of Li 1 + x Cr x Ti 2 − x (PO 4 ) 3 (x = 0–0.5) and Li 1.4 Al x Cr 0.4 − x Ti 1.6 (PO 4 ) 3 (x = 0–0.4) with the NASICON-type structure were synthesized using a precursor prepared by the sol–gel method. The highest total electrical conductivity of 3.55 × 10 − 4 S cm − 1 at 25 °C was obtained for x = 0.4 in Li 1 + x Cr x Ti 2 − x (PO 4 ) 3 (LACTP) sintered at 1120 °C for 6 h in air. Higher electrical conductivity was observed by the partial substitution of Cr 3 + with Al 3 + . The highest total electrical conductivity of 1.06 × 10 − 3 S cm − 1 and bulk conductivity of 1.77 × 10 − 3 S cm − 1 at 25 °C were obtained for x = 0.3 in Li 1.4 Al x Cr 0.4 − x Ti 1.6 (PO 4 ) 3 sintered at 1070 °C for 6 h in air. The contribution of electronic conductivity to the total conductivity was negligibly small. Li 1.4 Al 0.3 Cr 0.1 Ti 1.6 (PO 4 ) 3 was unstable in water, but stable in saturated LiOH with saturated LiCl aqueous solution. [ABSTRACT FROM AUTHOR]

The metabotropic γ-aminobutyric acid type B receptor (GABA B R) remains a hotspot in the recent research area. Being an idiosyncratic G-protein coupled receptor family member, the GABA B R manifests adaptively tailored functionality under multifarious modulations by a constellation of agents, pointing to cross-talk between receptors and effectors that converge on the domains of mood and memory. This review systematically summarizes the latest achievements in signal transduction mechanisms of the GABA B R-effector-regulator complex and probes how the up-and down-regulation of membrane-delimited GABA B Rs are associated with manifold intrinsic and extrinsic agents in synaptic strength and plasticity. Neuropsychiatric conditions depression and addiction share the similar pathophysiology of synapse inadaptability underlying negative mood-related processes, memory formations, and impairments. In the attempt to emphasize all convergent discoveries, we hope the insights gained on the GABA B R system mechanisms of action are conducive to designing more therapeutic candidates so as to refine the prognosis rate of diseases and minimize side effects. • Mood and memory disorders underpin two mental illnesses addiction and depression. • GABA B R functions as an elaborate system in mood and memory disorders. • KCTD protein is integral for GABA B R's functionality and membrane expression. • Modulations of the GABA B R-effector-regulator axis differ in separate brain regions. • Varied molecules influence the synaptic GABA B R expression conducing to diseases. [ABSTRACT FROM AUTHOR]

Heavy fermion metals provide a prototype setting to study quantum criticality. Experimentally, quantum critical points have been identified and studied in a growing list of heavy fermion compounds. Theoretically, Kondo destruction has provided a means to characterize a class of unconventional quantum critical points that goes beyond the Landau framework of order-parameter fluctuations. Among the prominent evidence for such local quantum criticality have been measurements in YbRh 2 Si 2 . A rapid crossover is observed at finite temperatures in the isothermal field dependence of the Hall coefficient and other transport and thermodynamic quantities, which specifies a T * B line in the temperature ( T )–magnetic field ( B ) phase diagram. Here, we discuss what happens when temperature is raised, by analyzing the ratio of the crossover width to the crossover position. With this ratio approaching unity at T ≳ 0.5 K , YbRh 2 Si 2 at zero magnetic field belongs to the quantum-critical fluctuation regime, where the single-particle spectral function has significant weight at both the small and large Fermi surfaces. This implies that, in this temperature range, any measurements sensitive to the Fermi surface will also see a significant spectral weight at the large Fermi surface. The angle-resolved photoemission spectroscopy experiments recently reported for YbRh 2 Si 2 at T > 1 K are consistent with this expectation, and therefore support the association of the T * B line with the physics of Kondo destruction. [ABSTRACT FROM AUTHOR]

The pore-forming subunits of the voltage-sensitive K+ channel (Kv) associate with ancillary β-subunits that regulate inactivation and voltage-dependence of the channel. The β-subunits are members of the aldo-keto reductase (AKR) superfamily. We have previously demonstrated that recombinant Kvβ2.1 displays tight binding to NADP(H). The protein also binds NAD(H), but with less affinity. To assess the physiological significance of this binding, we examined how pyridine nucleotides regulate the Kvβ-mediated inactivation of K+ channels. Transient transfection of COS-7 cells with an pIRES-hrGFP vector containing the Kvα1.5 cDNA led to the appearance of the Kv1.5 protein in the membrane fraction and large non-inactivating potassium currents were recorded from the transfected cells. No such currents were observed in cells transfected with the empty vector alone or with Kvβ1.3 (AKR6A3), which was localized to the cytoplasm. In contrast, Kvβ1.3 co-transfected with Kvα1.5 was localized to the membrane, suggesting high affinity binding of the two proteins. Moreover, the K currents recorded from cells transfected with both Kvα1.5 and Kvβ1.3 displayed pronounced inactivation. Inclusion of 1 mM NAD+ in the internal solution of the patch pipette abolished Kvβ-induced inactivation of Kv1.5 currents, but did not affect the non-inactivating currents recorded from cells transfected with Kv1.5 alone, indicating that in the absence of Kvβ, NAD+ does not affect the activity of Kvα. The inactivating currents recorded from cells expressing both Kvα1.5 and Kvβ1.3 were unaffected by the inclusion of 0.1 mM NADPH in the pipette solution. Together, these data suggest that NADPH and NAD+ impart different conformational states to the Kvβ protein and that only the NADPH bound Kvβ imparts inactivation to non-inactivating K+ currents. Thus, differential binding of pyridine nucleotide coenzymes to Kvβ could regulate membrane potential and excitability as a function of the cellular redox state. Because NAD+/NADPH ratio is sensitive to oxygen concentration, the differential changes in Kvβ-mediated inactivation of K currents by NAD+ and NADPH could represent an oxygen-sensing mechanism. [Copyright &y& Elsevier]

SmB 6 has been a well-known Kondo insulator for decades, but recently attracts extensive new attention as a candidate topological system. Studying SmB 6 under pressure provides an opportunity to acquire the much-needed understanding about the effect of electron correlations on both the metallic surface state and bulk insulating state. Here we do so by studying the evolution of two transport gaps (low temperature gap E l and high temperature gap E h ) associated with the Kondo effect by measuring the electrical resistivity under high pressure and low temperature (0.3 K) conditions. We associate the gaps with the bulk Kondo hybridization, and from their evolution with pressure we demonstrate an insulator-to-metal transition at ∼4 GPa. At the transition pressure, a large change in the Hall number and a divergence tendency of the electron-electron scattering coefficient provide evidence for a destruction of the Kondo entanglement in the ground state. Our results raise the new prospect for studying topological electronic states in quantum critical materials settings., (Copyright © 2017 Science China Press. Published by Elsevier B.V. All rights reserved.)