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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. Mature cardiac muscle requires high mitochondrial ATP production and specialized contractile proteins. Here the authors demonstrate that cardiomyocyte-specific contractile maturation involves cooperation between the nuclear receptor ERRγ and cardiogenic transcription factor GATA4, but ERRγ controls metabolic genes independently. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Polyurethane coating materials with different compositions of low surface energy polydimethylsiloxane and degradable poly(L-lactic acid) were synthesized by three major steps. Initially, the hydroxylation-terminated poly(L-lactide)-functionalized graphene (G-g-PLLA) was prepared by ring-opening polymerization of L-lactic acid using the phenol-functionalized graphene (G-f-OH), which was prepared by 1,3-dipolar cycloaddition reaction of graphene and 3,4-dihydroxybenzaldehyde when N-methylglycine and tin octoate were used as initiator and catalyst, respectively. Subsequently, isocyanate-terminated polyurethane prepolymer with polydimethylsiloxane was obtained by condensation polymerization of polydimethylsiloxane and isocyanate-terminated polyurethane prepolymer that was obtained by the condensation polymerization of 4,4′-diphenylmethane diisocyanate and 1,4-butane diol. Finally, the novel polyurethane coating materials were prepared by the condensation polymerization of G-g-PLLA and isocyanate-terminated polyurethane prepolymer with polydimethylsiloxane. These synthesized materials were carefully analyzed with Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectra (1H NMR), field-emission scanning electron microscopy (SEM), and high-resolution transmission (TEM). In addition, the water contact angles were measured. It was found that the surface free energy of the polyurethane coating materials decreased from 52.19 to 11.74 N/m2 with the increase of polydimethylsiloxane content from 0 to 20% and the water contact angle of the polyurethane coating materials increased from 71° to 108°. Moreover, the mechanical property was investigated. The studies also demonstrated that functionalized polyurethane was able to hydrolyze in seawater and the hydrolysis rate decreased as the PDMS content increased. At the same time, simulative ocean hanging plate experiment confirmed that the novel polyurethane coating materials exhibited a good antifouling performance, which indicated that the functionalized polyurethane has a potentiality in marine antifouling coating application. [ABSTRACT FROM AUTHOR]

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 after immersion for 7 days, and the charge transfer resistance ( R) of the three samples is 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 R, and the best surface quality. [ABSTRACT FROM AUTHOR]