Stable Field Emission from Single-Crystalline Zirconium Carbide Nanowires.

The <100> oriented single-crystalline Zirconium Carbide (ZrC) nanowires were controllably synthesized on a graphite substrate by chemical vapor deposition (CVD) with optimized growth parameters involving Zirconium tetrachloride (ZrCl), flow of methane (CH), and growth temperature. The length of nanowires is above 10 µm while the diameter is smaller than 100 nm. A single ZrC nanowire was picked up and fixed on a tungsten tip for field emission measurement.

Visualizing interfacial collective reaction behaviour of Li-S batteries.

Benefiting from high energy density (2,600 Wh kg) and low cost, lithium-sulfur (Li-S) batteries are considered promising candidates for advanced energy-storage systems. Despite tremendous efforts in suppressing the long-standing shuttle effect of lithium polysulfides, understanding of the interfacial reactions of lithium polysulfides at the nanoscale remains elusive. This is mainly because of the limitations of in situ characterization tools in tracing the liquid-solid conversion of unstable lithium polysulfides at high temporal-spatial resolution.

Tuning oxygen-containing functional groups of graphene for supercapacitors with high stability.

To investigate the relationship between the oxygen-containing functional groups of graphene and the stability of supercapacitors, reduced graphene oxide (rGO) containing different oxygenic functional groups was prepared by varying the reduction time of GO using hydrazine as the reducing agent. TEM, XRD, Raman, and XPS characterizations revealed that, as the reduction time increased, the sp structure in the rGO sheet was restored and the obtained rGO had good crystallinity accompanied by removal of the oxygenic functional groups. The analysis of the content of the different functional groups also suggested that the reduction rate of the oxygenic functional group was C-O > C[double bond, length as m-dash]O > O-C[double bond, length as m-dash]O.

Facile preparation of flexible binder-free graphene electrodes for high-performance supercapacitors.

A facile two-step strategy to prepare flexible graphene electrodes has been developed for supercapacitors using thermal reduction of graphene oxide (GO) and thermally reduced graphene oxide (TRGO) composite films. The tunable porous structure of the GO/TRGO film provided channels to release the high pressure generated by CO gas. The graphene electrode obtained from reduced-GO/TRGO (1 : 1 in mass ratio) film showed great flexibility and high film density (0.

Irisin Promotes Cardiac Homing of Intravenously Delivered MSCs and Protects against Ischemic Heart Injury.

Few intravenously administered mesenchymal stromal cells (MSCs) engraft to the injured myocardium, thereby limiting their therapeutic efficacy for the treatment of ischemic heart injury. Here, it is found that irisin pretreatment increases the cardiac homing of adipose tissue-derived MSCs (ADSCs) administered by single and multiple intravenous injections to mice with MI/R by more than fivefold, which subsequently increases their antiapoptotic, proangiogenic, and antifibrotic effects in rats and mice that underwent MI/R. RNA sequencing, Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway analysis, and loss-of-function studies identified CSF2RB as a cytokine receptor that facilitates the chemotaxis of irisin-treated ADSCs in the presence of CSF2, a chemokine that is significantly upregulated in the ischemic heart.

Stable field-emission from a CeB nanoneedle point electron source.

A single CeB nanoneedle structure has been fabricated using a focused ion beam (FIB) and its field emission characteristics have been evaluated. A converged electron beam has been obtained, attributed to its sharpened tip with a radius of curvature of about 10 nm. Combined with its low work function, the required electric field is as low as 1.

A "Biconcave-Alleviated" Strategy to Construct -Derived Carbon/MoS for Ultrastable Sodium Ion Storage.

Two-dimensional layered materials commonly face hindered electron transfer and poor structure stability, thus limiting their application in high-rate and long-term sodium ion batteries. In the current study, we adopt finite element simulation to guide the rational design of nanostructures. By calculating the von Mises stress distribution of a series of carbon materials, we find that the hollow biconcave structure could effectively alleviate the stress concentration resulting from expansion.

Reshaping the Cathodic Catalyst Layer for Anion Exchange Membrane Fuel Cells: From Heterogeneous Catalysis to Homogeneous Catalysis.

In anion exchange membrane fuel cells, catalytic reactions occur at a well-defined three-phase interface, wherein conventional heterogeneous catalyst layer structures exacerbate problems, such as low catalyst utilization and limited mass transfer. We developed a structural engineering strategy to immobilize a molecular catalyst tetrakis(4-methoxyphenyl)porphyrin cobalt(II) (TMPPCo) on the side chains of an ionomer (polyfluorene, PF) to obtain a composite material (PF-TMPPCo), thereby achieving a homogeneous catalysis environment inside ion-flow channels, with greatly improved mass transfer and turnover frequency as a result of 100 % utilization of the catalyst molecules. The unique structure of the homogeneous catalysis system comprising interconnected nanoreactors exhibits advantages of low overpotential and high fuel-cell power density.

Construction of Highly Active Metal-Containing Nanoparticles and FeCo-N Composite Sites for the Acidic Oxygen Reduction Reaction.

Metal-containing nanoparticles (M-NPs) in metal/nitrogen-doped carbon (M-N-C) catalysts have been considered hostile to the acidic oxygen reduction reaction (ORR). The relation between M-NPs and the active sites of metal coordinated with nitrogen (MN ) is hard to establish in acid medium owing to the poor stability of M-NPs. Herein, we develop a strategy to successfully construct a new FeCo-N-C catalyst containing highly active M-NPs and MN composite sites (M/FeCo-SAs-N-C).

Insight into Adsorption Performance and Mechanism on Efficient Removal of Methylene Blue by Accordion-like VCT MXene.

Dye-bearing wastewaters leading to the water pollution and ecological upset is a crucial issue in the textile industry. Herein, we report a facile method using two-dimensional transition metal carbides (MXenes) for the removal of the methylene blue (MB) in the water. The accordion-like VCT MXene is originally demonstrated to have high and spontaneous adsorption capacity of MB at 111.

Branched-Chain Amino Acids Exacerbate Obesity-Related Hepatic Glucose and Lipid Metabolic Disorders via Attenuating Akt2 Signaling.

Branched chain amino acids (BCAAs) are associated with the progression of obesity-related metabolic disorders, including type 2 diabetes and nonalcoholic fatty liver disease. However, whether BCAAs disrupt the homeostasis of hepatic glucose and lipid metabolism remains unknown. In this study, we observed that BCAAs supplementation significantly reduced high-fat (HF) diet-induced hepatic lipid accumulation while increasing the plasma lipid levels and promoting muscular and renal lipid accumulation.

N-Cadherin Overexpression Mobilizes the Protective Effects of Mesenchymal Stromal Cells Against Ischemic Heart Injury Through a β-Catenin-Dependent Manner.

Rationale: Mesenchymal stromal cell-based therapy is promising against ischemic heart failure. However, its efficacy is limited due to low cell retention and poor paracrine function. A transmembrane protein capable of enhancing cell-cell adhesion, N-cadherin garnered attention in the field of stem cell biology only recently.

Tailorable Hydrogel Improves Retention and Cardioprotection of Intramyocardial Transplanted Mesenchymal Stem Cells for the Treatment of Acute Myocardial Infarction in Mice.

Background Poor engraftment of intramyocardial stem cells limits their therapeutic efficiency against myocardial infarction (MI)-induced cardiac injury. Transglutaminase cross-linked Gelatin (Col-Tgel) is a tailorable collagen-based hydrogel that is becoming an excellent biomaterial scaffold for cellular delivery in vivo. Here, we tested the hypothesis that Col-Tgel increases retention of intramyocardially-injected stem cells, and thereby reduces post-MI cardiac injury.

Pretreatment of Diabetic Adipose-derived Stem Cells with mitoTEMPO Reverses their Defective Proangiogenic Function in Diabetic Mice with Critical Limb Ischemia.

Adipose-derived stem cells (ADSCs) have the ability to migrate to injury sites and facilitate tissue repair by promoting angiogenesis. However, the therapeutic effect of ADSCs from patients with diabetes is impaired due to oxidative stress. Given that diabetes is a group of metabolic disorders and mitochondria are a major source of reactive oxygen species (ROS), it is possible that mitochondrial ROS plays an important role in the induction of diabetic ADSC (dADSC) dysfunction.

Accurate measurement of the chirality of WS nanotubes.

We describe the structural parameters and atomic positions of a single-walled WS nanotube. The structure factor is calculated in detail using analytic expressions for both single-walled and multi-walled WS nanotubes. A zoning scheme has been developed to obtain the ratio m/n from the electron diffraction patterns.

Ultrasensitive Memristive Synapses Based on Lightly Oxidized Sulfide Films.

For biological synapses, high sensitivity is crucial for transmitting information quickly and accurately. Compared to biological synapses, memristive ones show a much lower sensitivity to electrical stimuli since much higher voltages are needed to induce synaptic plasticity. Yet, little attention has been paid to enhancing the sensitivity of synaptic devices.