The limitation of nanograined materials is their strong tendency to coarsen at elevated temperatures. As grain size decreases into the nanoscale, grain coarsening occurs at much lower temperatures, as low as ambient temperatures for some metals. We discovered that nanometer-sized grains in pure copper and nickel produced from plastic deformation at low temperatures exhibit notable thermal stability below a critical grain size. The instability temperature rises substantially at smaller grain sizes, and the nanograins remain stable even above the recrystallization temperatures of coarse grains. The inherent thermal stability of nanograins originates from an autonomous grain boundary evolution to low-energy states due to activation of partial dislocations in plastic deformation.

The effectiveness of a novel nickel-antimony doped tin oxide electrode for electrochemical degradation of organic pollutants was investigated using 4-chlorophenol (4-CP) as a model toxic organic. The experimental results demonstrate that the optimal Ni content was at Ni:Sn=1:500 in atomic ratio in the precursor coating solution, whereas the Sb:Sn ratio was set at 8:500. Using the electrode prepared with the optimal Ni doping ratio for 4-CP degradation, the charge-based efficiencies were up to 89 microg C(-1) for 4-CP destruction and 15 microg C(-1) for TOC removal, which were considerably higher than the efficiencies observed for other electrodes. It is suggested that the enhancement of the electrode for electrochemical oxidation of organics could be attributed to the production of hydroxyl radicals in anodic water electrolysis.

Fibroblast growth factor 21 (FGF21) is known as a potent metabolic regulator but its protective mechanisms against lipotoxicity-induced β-cell dysfunction and apoptosis remain elusive. Here, we aimed to examine the regulatory pathways whereby FGF21 mediates islet lipid metabolism in lipotoxicity-treated cells and animal models. Rat β-cell line (INS-1E cells) and islets isolated from C57/BL6J mice were exposed to palmitic acid (PA) with/without FGF21, mimicking lipotoxic conditions. Resultant insulin secretion and intracellular signaling were analyzed with Western blotting and RNA-seq. C57/BL6J and global FGF21 knockout (KO) mice were fed with a high-fat diet (HFD) to induce lipotoxicity and given with a long-acting mimetic of FGF21. Insulin resistance and β-cell function were then assessed using homeostasis model assessment of insulin resistance (HOMA-IR) and insulinogenic index. FGF21 ameliorated PA-induced lipid accumulation, reversed cell apoptosis, and enhanced glucose-stimulated insulin secretion (GSIS) as impaired by lipotoxicity in islet β-cells. Mechanistically, FGF21 exerted its beneficial effects through activation of AMPK-ACC (acetyl-CoA carboxylase) pathway and peroxisome proliferation-activated receptors (PPARs) δ/γ signaling, thus increasing the levels of carnitine palmitoyltransferase-1A (CPT1A) and leading to increased fatty acid (FA) oxidation and reduced lipid deposition in β-cells. Interestingly, FGF21 reduced PA-induced cell death via restoration of the expression of apoptosis inhibitor Birc3. In vivo studies further showed that FGF21 is critical for islet insulinogenic capacity and normal function in the context of HFD-treated animals. FGF21 down-regulates islet cell lipid accumulation, probably via activation of AMPK-ACC and PPARδ/γ signaling, and reduces cell death under lipotoxicity, indicating that FGF21 is protective against lipotoxicity-induced β-cell dysfunction and apoptosis.

High atomic diffusivity in metals enables substantial tuneability of their structure and properties by tailoring the diffusional processes, but this causes their customized properties to be unstable at elevated temperatures. Eliminating diffusive interfaces by fabricating single crystals or heavily alloying helps to address this issue but does not inhibit atomic diffusion at high homologous temperatures. We discovered that the Schwarz crystal structure was effective at suppressing atomic diffusion in a supersaturated aluminum–magnesium alloy with extremely fine grains. By forming these stable structures, diffusion-controlled intermetallic precipitation from the nanosized grains and their coarsening were inhibited up to the equilibrium melting temperature, around which the apparent across-boundary diffusivity was reduced by about seven orders of magnitude. Developing advanced engineering alloys using the Schwarz crystal structure may lead to useful properties for high-temperature applications.

A multicenter distorted-wave (MCDW) method for fast-electron-impact single ionization of a molecular system in the coplanar-asymmetric kinematics is developed. Plane waves are used to describe the fast incoming and outgoing electrons and the multicenter nature of the molecule is considered by describing the slow ejected electron with the multicenter distorted wave, which is solved from the anisotropic multicenter potential between the ejected electron and the ionic molecule. The MCDW method improves the conventional molecular distorted-wave methods, whose distorted wave is solved from the spherically averaged isotropic potential. The application to the water molecule shows reasonable agreement with the available experimental data.