Sharp faceted interfaces are often observed between compound precipitates and matrix phases, which are remarkably different in their lattice parameters. Multiple orientation relationships (ORs) ...corresponding to various faceted interfaces tend to coexist in one alloy. A near row matching (NRM) approach is proposed for a systematic investigation of ORs corresponding to potential preferred interfaces. Unlike a common practice to search for misorientations corresponding to low sigma grain boundaries associated with matching periodicity in three dimensions (3D), this approach directly searches for ORs that permit local 2D periodic good matching structures in preferred interfaces. The calculation method consists of two simple steps to evaluate matching within and between rows of lattice points. The method has been applied to a Mg
2
Sn/Mg system. Ten of the forty-four predicted facets agree with the experimental observations, for the cases that the preferred facets can be described (approximately) by low index planes of the precipitates. The predictions can cover all known observations, if limited high index planes are included as candidates. Each observed facet is characterized with a periodic pattern of good matching sites (GMSs) in localized regions. NRM is a necessary condition for the existence of a periodic GMS pattern. The agreement between the calculation results and experimental results confirms the important role of periodic matching in the development of preferred interfaces and their corresponding ORs. It also demonstrates the usefulness of geometric matching study for quantitative predictions of potential preferred interfaces.
Abstract
Two-dimensional (2D) materials offer a prospect of membranes that combine negligible gas permeability with high proton conductivity and could outperform the existing proton exchange ...membranes used in various applications including fuel cells. Graphene oxide (GO), a well-known 2D material, facilitates rapid proton transport along its basal plane but proton conductivity across it remains unknown. It is also often presumed that individual GO monolayers contain a large density of nanoscale pinholes that lead to considerable gas leakage across the GO basal plane. Here we show that relatively large, micrometer-scale areas of monolayer GO are impermeable to gases, including helium, while exhibiting proton conductivity through the basal plane which is nearly two orders of magnitude higher than that of graphene. These findings provide insights into the key properties of GO and demonstrate that chemical functionalization of 2D crystals can be utilized to enhance their proton transparency without compromising gas impermeability.
Rasal1 is a Ras GTPase-activating protein which contains C2 domains necessary for dynamic membrane association following intracellular calcium elevation. Membrane-bound Rasal1 inactivates Ras ...signaling through its RasGAP activity, and through such mechanisms has been implicated in regulating various cellular functions in the context of tumors. Although highly expressed in the brain, the contribution of Rasal1 to neuronal development and function has yet to be explored.
We examined the contributions of Rasal1 to neuronal development in primary culture of hippocampal neurons through modulation of Rasal1 expression using molecular tools. Fixed and live cell imaging demonstrate diffuse expression of Rasal1 throughout the cell soma, dendrites and axon which localizes to the neuronal plasma membrane in response to intracellular calcium fluctuation. Pull-down and co-immunoprecipitation demonstrate direct interaction of Rasal1 with PKC, tubulin, and CaMKII. Consequently, Rasal1 is found to stabilize microtubules, through post-translational modification of tubulin, and accordingly inhibit dendritic outgrowth and branching. Through imaging, molecular, and electrophysiological techniques Rasal1 is shown to promote NMDA-mediated synaptic activity and CaMKII phosphorylation.
Rasal1 functions in two separate roles in neuronal development; calcium regulated neurite outgrowth and the promotion of NMDA receptor-mediated postsynaptic events which may be mediated both by interaction with direct binding partners or calcium-dependent regulation of down-stream pathways. Importantly, the outlined molecular mechanisms of Rasal1 may contribute notably to normal neuronal development and synapse formation.
Performance of the BL03U beamline at SSRF Sun, Z. P.; Liu, Z. H.; Liu, Z. T. ...
Journal of synchrotron radiation,
September 2020, Letnik:
27, Številka:
5
Journal Article
Recenzirano
The vacuum ultraviolet beamline BL03U with a photon energy range from 7 eV upwards has been constructed at the 3.5 GeV Shanghai Synchrotron Radiation Facility. Equipped with an APPLE‐Knot undulator, ...this beamline is dedicated to angle‐resolved photoemission spectroscopy. An energy‐resolving power of higher than 4.6 × 104 has been achieved in the photon energy range 21.6–48 eV, which is almost the same as the theoretical estimation.
The design and performance test of the vacuum ultraviolet beamline BL03U at SSRF are described.
Abstract
This study aimed to evaluate the effects of vitamin C and vitamin E on antioxidant capacity and immune function in oxidative-stressed breeder roosters. One hundred twenty 45-week-old Lveyang ...black-boned breeder roosters were randomly assigned to 5 dietary treatments, including negative control group (NC), positive control group (PC), and 3 trial groups, which were fed the diets containing 300 mg/kg VC, 200 mg/kg VE, or 300 mg/kg VC and 200 mg/kg VE (VC+VE). At 47 wk of age, the positive control and trial groups were subcutaneously injected 3 times every other d with dexamethasone (DEX) 4 mg/kg of body weight, the negative control group was injected with saline. The experiment lasted for 35 d. The results showed that at 50 wk of age, average daily feed intake of birds challenged with DEX significantly increased (P < 0.05). During post-stress recovery period (52 wk of age), dietary supplemental VE or VC+VE notably increased body weight under oxidative stress (P < 0.01). Oxidative stress induced by DEX could significantly decrease superoxide dismutase (SOD), IgM, antibody titer of ND and mRNA expression of SOD or glutathion peroxidase activity (GSH-Px), increase serous malondialdehyde (MDA) (P < 0.05). Supplementation of VC or VE significantly decreased serous MDA, and increased SOD under oxidative stress (P < 0.05). Supplementation of VC or VE, or their combination significantly increased the relative expression of GSH-Px mRNA when compared to the oxidative-stressed control treatment (P < 0.05), whereas did not alleviate the relative expression of SOD mRNA (P > 0.05). Therefore, the results suggest that addition of 300 mg/kg VC, 200 mg/kg VE or their combination could improve antioxidant ability and immune performance in oxidative-stressed breeder roosters through up-regulating the expression of GSH-Px gene.
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