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Uranium silicide compounds have attracted intensive attention as candidate alternative fuels in commercial light water reactors (LWRs). In this work, the electronic, thermal, mechanical and elastic properties of U3Si5 are comprehensively investigated based on first-principles density functional calculations and semi-classical Boltzmann transport theory. U3Si5 is determined to be a brittle and magnetic metal, and thermal conductivity is dominated by its electronic contribution at high temperature. The ratio between the bulk and shear moduli is 1.205. In addition, the elastic ideal strength is strongly anisotropic, with the minimum value only 6.831 GPa at a uniaxial tensile strain of 0.07. This low strength is mainly caused by an emerged structural transition forming silicon-silicon bonds to absorb strain energy. Moreover, the influences of aluminum incorporation on the structural and elastic properties, and thermal conductivities of U3Si5 are further studied. The aluminum atom prefers to replace the silicon atom at the vertex shared by the silicon triangles and pentagons. The incorporated atom impedes the structural transition, and enhances the toughness of U3Si5. The results from this work may provide useful clue for the improvement in the application of U3Si5.

Podocyte damage is the initial hallmark of diabetic nephropathy (DN), leading to the increasing morbidity and mortality in diabetic patients. Recent researches have corroborated the critical roles of miRNAs in the pathological progression of DN. Here, elevation of miR-217 was verified in high glucose (HG)-stimulated podocytes. Moreover, blocking miR-217 expression antagonized HG-induced cell injury by attenuating the adverse role of HG on cell viability and inhibiting ROS levels and cell apoptosis. Simultaneously, miR-217 repression restored HG-disrupted insulin resistance by elevating glucose uptake and nephrin expression, an essential component for insulin-induced glucose uptake. Mechanism assay substantiated the defective autophagy in HG-treated podocytes, which was resumed by miR-217 cessation. Importantly, suppressing autophagy pathway with 3-MA alleviated the protective roles of miR-217 down-regulation in podocyte injury and insulin resistance. Luciferase reporter analysis confirmed that PTEN was a target of miR-217 in podocytes. Additionally, blocking PTEN expression restrained autophagy restoration in miR-217-decreased cells. Furthermore, PTEN down-regulation attenuated the beneficial role of miR-217 suppression in HG-induced injury and insulin resistance. Together, this study manifests that miR-217inhibition can protectively antagonize HG-induced podocyte damage and insulin resistance by restoring the defective autophagy pathway via targeting PTEN, representing a novel and promising therapeutic target against diabetic nephropathy.

Arbuscular mycorrhizal fungal (AMF) colonization can induce both the local and the systemic increase in phenolic accumulation in hosts. However, the signaling molecules responsible for the systemic induction is still unclear. In this study, a split-root rhizobox system was designed to explore these molecules, with one half of clover (Trifolium repense) roots colonized by AMF, Funneliformis mosseae (formerly known as Glomus mosseae), and the other not (NM/M). Plants with two halves both (M/M) or neither (NM/NM) inoculated were also established for comparison. The contents of phenols and the accumulation of salicylic acid (SA), hydrogen peroxide (H2O2) and nitric oxide (NO) in roots were monitored, the activities of l -phenylalanine ammonia-lyase (PAL) and nitric oxide synthase (NOS) in roots were assayed, and the expressions of pal and chs (gene encoding chalcone synthase) genes in roots were also quantified using qRT-PCR. Results indicated that when phenolic content in NM/NM plants was lower than that in M/M plants, AMF colonization systemically induced the increase in phenolic content in NM/M plants. Similarly, the accumulations of SA and H2O2 were increased by AMF both locally and systemically, while that of NO was only increased locally. Moreover, enzyme assay and qRT-PCR were in accordance with these results. These data suggest that AMF colonization can systemically increase the phenolic biosynthesis, and SA and H2O2 are possibly the signaling molecules involved. The role of MeSA, a signaling molecule capable of long distance transport in this process, is also discussed.

Scientists have found that the size of the cavity of endohedral metallofullerenes (EMFs) can influence the properties of the inner molecule. In this work, the neutral diuranium molecule was encapsulated into the C90 fullerene. The neutral U-U dissociation potential energy surfaces of different electronic states confined in the C90 fullerene were scanned and the quintuple and the septuplet of these states were found to be low-lying. In the fullerene cage, the U2 molecule easily disintegrates along the axis of the fullerene, and then is chemically adsorbed on the both ends of the fullerene. The charge distribution and the molecular orbit properties of the complex were also uncovered.

Reliable structural information of extremal points in a reaction is important but difficult to achieve in molecular chiral transitions under confinement due to the complex molecular interactions. In this Letter, based on statistical results of a number of classical molecular dynamics simulations, we found that a complete chiral transition process of a difluorobenzo[c]phenanthrene molecule (C18H12F2, called D molecule) within a single-walled boron-nitride nanotube involves at least five extremal point structures, showing a unique feature of chiral transition in the confined environment and suggesting an alternative to conventional first-principles calculations to determine the complex potential energy surface of intermolecular interactions.