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Refractory high-entropy alloys (HEAs) are promising structure materials in elevated temperature. In the present studies, refractory WMoNbTiCr HEAs with different Cr content were prepared by mechanical alloying followed spark plasma sintering. The effects of chromium content on microstructure and room temperature mechanical properties of WMoNbTiCr HEAs were investigated. The results showed that there are three body-centered cubic (BCC) solid solution phases in the ball-milled powders, including enriching with W, Nb, and Cr solid solution phases, respectively. The bulk WMoNbTiCr alloys were mainly composed of disordered BCC phases and a small amount of Laves phase. As the content of Cr increased from 5 to 20 at.%, the relative content of Laves phase increased correspondingly. With an increase in Cr content, the hardness, fracture toughness, compressive fracture strength, and compressive strain of the WMoNbTiCr HEAs increased, exhibiting the maximum values of 9.73 GPa, 6.68 MPa m1/2, 2116 MPa, and 5.1%, respectively. With an addition of 20 at.% Cr, the WMoNbTiCr HEA exhibited a more refined microstructure. The increasing fracture toughness and compressive strain were mainly attributed to the grain refinement. However, the solid solution strengthening, the second-phase (Laves phase) strengthening, and microstructure refinement resulted in an increase in the hardness and compressive fracture strength.

Estrogen-related receptors (ERR) α and γ were shown recently to serve as regulators of cardiac maturation, yet the underlying mechanisms have not been delineated. Herein, we find that ERR signaling is necessary for induction of genes involved in mitochondrial and cardiac-specific contractile processes during human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) differentiation. Genomic interrogation studies demonstrate that ERRγ occupies many cardiomyocyte enhancers/super-enhancers, often co-localizing with the cardiogenic factor GATA4. ERRγ interacts with GATA4 to cooperatively activate transcription of targets involved in cardiomyocyte-specific processes such as contractile function, whereas ERRγ-mediated control of metabolic genes occurs independent of GATA4. Both mechanisms require the transcriptional coregulator PGC-1α. A disease-causing GATA4 mutation is shown to diminish PGC-1α/ERR/GATA4 cooperativity and expression of ERR target genes are downregulated in human heart failure samples suggesting that dysregulation of this circuitry may contribute to congenital and acquired forms of heart failure.

It is crucial to develop highly sensitive and selective sensors for ammonia, one of the most common toxic gases which have been widely used in pharmaceutical, chemical, and manufacturing industries. In this study, graphene oxide (GO) film was spin-coated onto surfaces of ST-cut quartz surface acoustic wave (SAW) devices with a resonant frequency of 200 MHz for ammonia sensing. The oxygen-containing functional groups (such as hydroxyl and epoxy ones) on the surface of GO film strongly absorb ammonia molecules and thus increase the film stiffness. This is attributed to the main ammonia sensing mechanism of the Love mode SAW devices, which show not only a positive frequency shift of 620 Hz for 500 ppb ammonia gas, but also an excellent selectivity (as compared to other gases such as H2, H2S, CO, and NO2) and a good reproducibility, operated at room temperature of 22 °C.

Dense oxidation coatings have been successfully developed on biocompatible AZ31 magnesium alloy, using microarc oxidation technique, to improve the corrosion resistance. Three different deposition voltages of 250, 300, and 350 V have been employed. The effect of voltage on the coating corrosion resistance has been evaluated through electrochemical experiments in a simulated body fluid (SBF) up to 7 days. Potentiodynamic polarization and electrochemical impedance spectroscopy scans were performed in the SBF solution, followed by optical microscopy surface inspection. The results indicate that the corrosion rates of the coatings are in the order of 250 300 > 350 V. Both the electrochemical tests and the surface inspection suggest that the 250 V coating has the highest corrosion resistance, with lowest corrosion current density, highest Rct, and the best surface quality.