Energy and glucose homeostasis are regulated by food intake and liver glucose production, respectively. The upper intestine has a critical role in nutrient digestion and absorption. However, studies ...indicate that upper intestinal lipids inhibit food intake as well in rodents and humans by the activation of an intestine-brain axis. In parallel, a brain-liver axis has recently been proposed to detect blood lipids to inhibit glucose production in rodents. Thus, we tested the hypothesis that upper intestinal lipids activate an intestine-brain-liver neural axis to regulate glucose homeostasis. Here we demonstrate that direct administration of lipids into the upper intestine increased upper intestinal long-chain fatty acyl-coenzyme A (LCFA-CoA) levels and suppressed glucose production. Co-infusion of the acyl-CoA synthase inhibitor triacsin C or the anaesthetic tetracaine with duodenal lipids abolished the inhibition of glucose production, indicating that upper intestinal LCFA-CoAs regulate glucose production in the preabsorptive state. Subdiaphragmatic vagotomy or gut vagal deafferentation interrupts the neural connection between the gut and the brain, and blocks the ability of upper intestinal lipids to inhibit glucose production. Direct administration of the N-methyl-d-aspartate ion channel blocker MK-801 into the fourth ventricle or the nucleus of the solitary tract where gut sensory fibres terminate abolished the upper-intestinal-lipid-induced inhibition of glucose production. Finally, hepatic vagotomy negated the inhibitory effects of upper intestinal lipids on glucose production. These findings indicate that upper intestinal lipids activate an intestine-brain-liver neural axis to inhibit glucose production, and thereby reveal a previously unappreciated pathway that regulates glucose homeostasis.
A novel CrCoNiSix (x = 0.1, 0.2, 0.3) medium entropy alloys (MEAs) system was designed to achieve enhanced strength and ductility. The CrCoNiSix MEAs are all single-phase face-centered cubic (FCC) ...structure. The recrystallization rate and average grain size obviously increase with the increase of Si. Compared to CrCoNi MEA, the ultimate tensile strength (UTS) and uniform elongation (UE) of CrCoNiSi0.3 MEA were increased from 790 MPa to 960 MPa and 58% to 92%, respectively, and the product of UTS and total elongation (TE) increased up to 88 GPa% (46 GPa% for CoCrNi MEA), superior to most high strength-ductility alloys. The stacking-fault energy (SFE) in the Si-added MEAs decreases with Si addition, as proved by thermodynamic model. Therefore, the underlying strengthening mechanism is the reduction of SFE and increase in the lattice distortion via Si addition. More concentrated and thinner deformation twins and multiple twinning structures were observed in Si-added MEAs. Furthermore, a nanoscale diffusionless transformation from the FCC to the hexagonal close-packed (HCP) phase occurred at room-temperature tension in Si-added MEAs, which further increased the work hardening and uniform elongation. This work provides a new and significant approach to break through the strength-ductility trade-off in FCC MEAs/HEAs, especially serving as energy-absorbing materials.
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•The strength and ductility of CrCoNi MEA are both significantly improved by adding Si element.•CrCoNiSi0.3 MEA exhibits outstanding product of ultimate tensile strength and total elongation, exceeding most of existing alloys tensioned at room temperature.•The recrystallization rate and the average grain size are obviously increased with the increase of Si content.•Nanoscale transformation from FCC to HCP phase occurs at ambient temperature deformation for Si-added CrCoNiSix MEA.
We use 26×106 galaxies from the Dark Energy Survey (DES) Year 1 shape catalogs over 1321 deg2 of the sky to produce the most significant measurement of cosmic shear in a galaxy survey to date. We ...constrain cosmological parameters in both the flat ΛCDM and the wCDM models, while also varying the neutrino mass density. These results are shown to be robust using two independent shape catalogs, two independent photo-z calibration methods, and two independent analysis pipelines in a blind analysis. We find a 3.5% fractional uncertainty on σ8(Ωm/0.3)0.5=0.782−0.027+0.027 at 68% C.L., which is a factor of 2.5 improvement over the fractional constraining power of our DES Science Verification results. In wCDM, we find a 4.8% fractional uncertainty on σ8(Ωm/0.3)0.5=0.777−0.038+0.036 and a dark energy equation-of-state w=−0.95−0.39+0.33. We find results that are consistent with previous cosmic shear constraints in σ8-Ωm, and we see no evidence for disagreement of our weak lensing data with data from the cosmic microwave background. Finally, we find no evidence preferring a wCDM model allowing w≠−1. We expect further significant improvements with subsequent years of DES data, which will more than triple the sky coverage of our shape catalogs and double the effective integrated exposure time per galaxy.
Ultra-small metal clusters have attracted great attention owing to their superior catalytic performance and extensive application in heterogeneous catalysis. However, the synthesis of high-density ...metal clusters is very challenging due to their facile aggregation. Herein, one-step pyrolysis was used to synthesize ultra-small clusters and single-atom Fe sites embedded in graphitic carbon nitride with high density (iron loading up to 18.2 wt %), evidenced by high-angle annular dark field-scanning transmission electron microscopy, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, and 57Fe Mössbauer spectroscopy. The catalysts exhibit enhanced activity and stability in degrading various organic samples in advanced oxidation processes. The drastically increased metal site density and stability provide useful insights into the design and synthesis of cluster catalysts for practical application in catalytic oxidation reactions.
There is increasing interest in both relating the mechanical behavior of high-entropy alloys to their microstructural evolution and in their development for various applications. A special two-day ...international workshop on the above topic was held in Guiyang, China, in December 2014. The workshop gathered scientists and engineers to exchange information on recent progress in high-entropy alloys, to discuss the scientific issues and challenges to foster international collaborations, and to identify future directions. In this paper, a summary of this workshop is presented, including aspects of definition/terminology, phase formation, microstructure and phase stability, strengthening mechanisms, and high-temperature properties. Future research directions are also outlined.
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•Recent progress in several critical topics of the high-entropy alloys was briefly summarized.•Special emphasis was placed on the relationship between mechanical properties and microstructure.•Future research directions of the discussed areas in HEAs are also outlined.
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