Sn4P3 is introduced for the first time as an anode material for Na‐ion batteries. Sn4P3 delivers a high reversible capacity of 718 mA h g−1, and shows very stable cycle performance with negligible ...capacity fading over 100 cycles, which is attributed to the confinement effect of Sn nanocrystallites in the amorphous phosphorus matrix during cycling.
Aging-related impairments in hippocampus-dependent cognition have been attributed to maladaptive changes in the functional properties of pyramidal neurons within the hippocampal subregions. Much ...evidence has come from work on CA1 pyramidal neurons, with CA3 pyramidal neurons receiving comparatively less attention despite its age-related hyperactivation being postulated to interfere with spatial processing in the hippocampal circuit. Here, we use whole-cell current-clamp to demonstrate that aged rat (29-32 months) CA3 pyramidal neurons fire significantly more action potentials (APs) during theta-burst frequency stimulation and that this is associated with faster AP repolarization (i.e., narrower AP half-widths and enlarged fast afterhyperpolarization). Using a combination of patch-clamp physiology, pharmacology, Western blot analyses, immunohistochemistry, and array tomography, we demonstrate that these faster AP kinetics are mediated by enhanced function and expression of Kv4.2/Kv4.3 A-type K(+) channels, particularly within the perisomatic compartment, of CA3 pyramidal neurons. Thus, our study indicates that inhibition of these A-type K(+) channels can restore the intrinsic excitability properties of aged CA3 pyramidal neurons to a young-like state. Significance statement: Age-related learning deficits have been attributed, in part, to altered hippocampal pyramidal neuronal function with normal aging. Much evidence has come from work on CA1 neurons, with CA3 neurons receiving comparatively less attention despite its age-related hyperactivation being postulated to interfere with spatial processing. Hence, we conducted a series of experiments to identify the cellular mechanisms that underlie the hyperexcitability reported in the CA3 region. Contrary to CA1 neurons, we demonstrate that postburst afterhyperpolarization is not altered with aging and that aged CA3 pyramidal neurons are able to fire significantly more action potentials and that this is associated with faster action potential repolarization through enhanced expression of Kv4.2/Kv4.3 A-type K(+) channels, particularly within the cell bodies of CA3 pyramidal neurons.
All‐solid‐state sodium‐ion batteries that operate at room temperature are attractive candidates for use in large‐scale energy storage systems. However, materials innovation in solid electrolytes is ...imperative to fulfill multiple requirements, including high conductivity, functional synthesis protocols for achieving intimate ionic contact with active materials, and air stability. A new, highly conductive (1.1 mS cm−1 at 25 °C, Ea=0.20 eV) and dry air stable sodium superionic conductor, tetragonal Na3SbS4, is described. Importantly, Na3SbS4 can be prepared by scalable solution processes using methanol or water, and it exhibits high conductivities of 0.1–0.3 mS cm−1. The solution‐processed, highly conductive solidified Na3SbS4 electrolyte coated on an active material (NaCrO2) demonstrates dramatically improved electrochemical performance in all‐solid‐state batteries.
Dissolve and solidify: A new and highly conductive (1.1 mS cm−1), dry air‐stable sodium superionic conductor, tetragonal Na3SbS4, was developed. Importantly, its solution processability using methanol or water allows direct coating onto active materials. The solution‐processed highly conductive (0.1–0.3 mS cm−1) solidified Na3SbS4 coating on NaCrO2 solves the poor ionic contact problem in all‐solid‐state sodium‐ion batteries.
Electrochemical impedance analysis is performed to predict the rate capability of two commercial activated carbon electrodes (RP20 and MSP20) for electric double-layer capacitor. To this end, ac ...impedance data are fitted with an equivalent circuit that comprises ohmic resistance and impedance of intra-particle pores. To characterize the latter, ionic accessibility into intra-particle pores is profiled by using the fitted impedance parameters, and the profiles are transformed into utilizable capacitance plots as a function of charge–discharge rate. The rate capability that is predicted from the impedance analysis is well-matched with that observed from a charge–discharge rate test. It is found that rate capability is determined by ionic accessibility as well as ohmic voltage drop. A lower value in ionic accessibility for MSP20 is attributed to smaller pore diameter, longer length, and higher degree of complexity in pore structure.
Display omitted
•Rate capability of EDLC was quantitatively predicted by an impedance measurement.•Ohmic resistance and pores' ionic accessibility were factorized by EIS.•From the two factors, ohmic voltage drop and utilizable capacitance was derived.•A key formula was devised to correlate the ac with dc information of EDLC.•Thus predicted rate capabilities were verified by comparing with cell test results.
Alternatively activated macrophages (M2) have an important function in innate immune responses to parasitic helminths, and emerging evidence also indicates these cells are regulators of systemic ...metabolism. Here we show a critical role for mTORC2 signalling in the generation of M2 macrophages. Abrogation of mTORC2 signalling in macrophages by selective conditional deletion of the adaptor molecule Rictor inhibits the generation of M2 macrophages while leaving the generation of classically activated macrophages (M1) intact. Selective deletion of Rictor in macrophages prevents M2 differentiation and clearance of a parasitic helminth infection in mice, and also abrogates the ability of mice to regulate brown fat and maintain core body temperature. Our findings define a role for mTORC2 in macrophages in integrating signals from the immune microenvironment to promote innate type 2 immunity, and also to integrate systemic metabolic and thermogenic responses.
The corrosion behavior of aluminum foil that is used as the positive current collector for lithium-ion batteries is studied in N-methyl-N-propyl-pyrrolidinium bis(fluorosulfonyl)imide (PMPyr-FSI), ...which is considered as a highly attractive solvent due to a very low viscosity. This work reports that FSI anion is corrosive for aluminum foil upon anodic polarization (>4.0V vs. Li/Li+). The pitting corrosion is, however, greatly reduced by adding lithium hexafluorophosphate (LiPF6). The anion of the salt is known to be a corrosion inhibitor for aluminum. It likely reacts to generate hydrofluoric acid that then attacks the native aluminum oxide (Al2O3) to produce a strong passivation layer comprising aluminum fluoride (AlF3). Resultantly, the high rate capability, which is the potential merit achievable by using the FSI-containing ionic liquid solvent, can be implemented with a LiCoO2 positive electrode.
► Al positive current collector is corroded by an attack of FSI anion. ► Addition of LiPF6 leads to a formation of a strong passivation layer (AlF3). ► The absence of corrosion on the Al current collector allows a stable cycling of LiCoO2 electrode. ► A high-rate cycling is achieved by using the FSI-based ionic liquid solvent of low viscosity.
Interactions with the microenvironment modulate the fate of stem cells in perivascular niches in tissues (e.g., bone) and organs (e.g., liver). However, the functional relevance of the molecular ...crosstalk between endothelial cells and stem cells within the perivascular niche in dental pulps is unclear. Here, we tested the hypothesis that endothelial cell–initiated signaling is necessary to maintain self-renewal of dental pulp stem cells. Confocal microscopy showed that ALDH1high and Bmi-1high stem cells are preferentially localized in close proximity to blood vessels in physiological human dental pulps. Secondary orosphere assays revealed that endothelial cell–derived factors (e.g., interleukin-6 IL-6) promote self-renewal of dental pulp stem cells cultured in low-attachment conditions. Mechanistic studies demonstrated that endothelial cell–derived IL-6 activates IL-6R (IL-6 Receptor) and signal transducer and activator of transcription 3 (STAT3) signaling and induces expression of Bmi-1 (master regulator of stem cell self-renewal) in dental pulp stem cells. Transplantation of dental pulp stem cells stably transduced with small hairpin RNA (shRNA)–STAT3 into immunodeficient mice revealed a decrease in the number of blood vessels surrounded by ALDH1high or Bmi-1high cells (perivascular niches) compared to tissues formed upon transplantation of vector control stem cells. And finally, in vitro capillary sprouting assays revealed that inhibition of IL-6 or STAT3 signaling decreases the vasculogenic potential of dental pulp stem cells. Collectively, these data demonstrate that endothelial cell–derived IL-6 enhances the self-renewal of dental pulp stem cells via STAT3 signaling and induction of Bmi-1. These data suggest that a crosstalk between endothelial cells and stem cells within the perivascular niche is required for the maintenance of stem cell pools in dental pulps.
Single-ion conducting electrolytes present a unique alternative to traditional binary salt conductors used in lithium-ion batteries. It has been shown theoretically that single-ion electrolytes can ...eliminate the salt concentration gradient and polarization loss in the cell that develop in a binary salt system, resulting in substantial improvements in materials utilization for high power and energy densities. Here, we describe synthesis and characterization of a class of single-ion electrolytes based on aromatic poly(arylene ether)s with pendant lithium perfluoroethyl sulfonates. The microporous polymer film saturated with organic carbonates exhibits a nearly unity Li+ transference number, very high conductivities (e.g., > 10–3 S m–1 at room temperature) over a wide range of temperatures, great electrochemical stability, and outstanding mechanical properties. Excellent cyclability with almost identical charge and discharge capacities has been demonstrated at ambient temperature in the batteries assembled from the prepared single-ion conductors.
Disodium terephthalate and its various derivatives are synthesized via simple acid‐base chemistry for anode materials in Na ion batteries. They show excellent electrochemical performance, including ...little capacity fading over 90 cycles, ideal redox potential, and excellent rate performance, making them promising candidates for Na ion batteries.
PDF
