Multi-Objective Optimization for Spectrum and Energy Efficiency Tradeoff in IRS-Assisted CRNs with NOMA

Non-orthogonal multiple access (NOMA) is a promising candidate for the sixth generation wireless communication networks due to its high spectrum efficiency (SE), energy efficiency (EE), and better connectivity. It can be applied in cognitive radio networks (CRNs) to further improve SE and user connectivity. However, the interference caused by spectrum sharing and the utilization of non-orthogonal resources can downgrade the achievable performance. In order to tackle this issue, intelligent reflecting surface (IRS) is exploited in a downlink multiple-input-single-output (MISO) CRN with NOMA. To realize a desirable tradeoff between SE and EE, a multi-objective optimization (MOO) framework is formulated under both the perfect and imperfect channel state information (CSI). An iterative block coordinate descent (BCD)-based algorithm is exploited to optimize the beamforming design and IRS reflection coefficients iteratively under the perfect CSI case. A safe approximation and the S-procedure are used to address the non-convex infinite inequality constraints of the problem under the imperfect CSI case. Simulation results demonstrate that the proposed scheme can achieve a better balance between SE and EE than baseline schemes. Moreover, it is shown that both SE and EE of the proposed algorithm under the imperfect CSI can be significantly improved by exploiting IRS

Itinerant ferromagnetism and intrinsic anomalous Hall effect in amorphous iron-germanium

The amorphous iron-germanium system (a-FexGe1-x) lacks long-range structural order and hence lacks a meaningful Brillouin zone. The magnetization of a-FexGe1-x is well explained by the Stoner model for Fe concentrations x above the onset of magnetic order around x=0.4, indicating that the local order of the amorphous structure preserves the spin-split density of states of the Fe-3d states sufficiently to polarize the electronic structure despite k being a bad quantum number. Measurements reveal an enhanced anomalous Hall resistivity ρxyAH relative to crystalline FeGe; this ρxyAH is compared to density-functional theory calculations of the anomalous Hall conductivity to resolve its underlying mechanisms. The intrinsic mechanism, typically understood as the Berry curvature integrated over occupied k states but shown here to be equivalent to the density of curvature integrated over occupied energies in aperiodic materials, dominates the anomalous Hall conductivity of a-FexGe1-x (0.38≤x≤0.61). The density of curvature is the sum of spin-orbit correlations of local orbital states and can hence be calculated with no reference to k space. This result and the accompanying Stoner-like model for the intrinsic anomalous Hall conductivity establish a unified understanding of the underlying physics of the anomalous Hall effect in both crystalline and disordered systems

Study on the anti-cerebral ischemia effect of borneol and its mechanism

Background: Borneol is the processed item from resin of Dryobalanops aromatica Gaertn. f. It can enhance the activity of antioxidant enzymes in brain tissue and reduce inflammatory response by improving the energy metabolism of ischemic brain regions, and thereby reduces brain tissue damage. The objective of this paper was to study the anti-cerebral ischemia effect of borneol and its mechanism.Materials and Methods: The anti-cerebral ischemia effect of borneol was studied by ligation of bilateral common carotid arteries (CCA), and vagus nerves in mice and the acute cerebral ischemia-reperfusion experiment in rats.Results: Compared with the blank and solvent control groups, the borneol low-; medium-; and high-dose groups can significantly prolong the gasping time of mice after decapitation, and extend the survival time of mice after ligation of bilateral CCA, and vagus nerves.Conclusion: Compared with the Xueshuantong injection group, the prolongation of survival time of mice after ligation of bilateral CCA, and vagus nerves was more apparent in the high-dose borneol experimental group; each experimental group can significantly reduce the number of leukocyte infiltration, the number of ICAM-1-positive vessels, as well as the number of TNF-α-positive cells.Conclusion: Borneol has an anti-cerebral ischemia effect.Key words: borneol; cerebral ischemia-reperfusion; IL-1β, TNF-α; ICAM-

Probing Nucleation Mechanism of Self-Catalyzed InN Nanostructures

The nucleation and evolution of InN nanowires in a self-catalyzed growth process have been investigated to probe the microscopic growth mechanism of the self-catalysis and a model is proposed for high pressure growth window at ~760 Torr. In the initial stage of the growth, amorphous InNx microparticles of cone shape in liquid phase form with assistance of an InNx wetting layer on the substrate. InN crystallites form inside the cone and serve as the seeds for one-dimensional growth along the favorable [0001] orientation, resulting in single-crystalline InN nanowire bundles protruding out from the cones. An amorphous InNx sheath around the faucet tip serves as the interface between growing InN nanowires and the incoming vapors of indium and nitrogen and supports continuous growth of InN nanowires in a similar way to the oxide sheath in the oxide-assisted growth of other semiconductor nanowires. Other InN 1D nanostructures, such as belts and tubes, can be obtained by varying the InN crystallites nucleation and initiation process

In situ epitaxial engineering of graphene and h-BN lateral heterostructure with a tunable morphology comprising h-BN domains

Graphene and hexagonal boron nitride (h-BN), as typical two-dimensional (2D) materials, have long attracted substantial attention due to their unique properties and promise in a wide range of applications. Although they have a rather large difference in their intrinsic bandgaps, they share a very similar atomic lattice; thus, there is great potential in constructing heterostructures by lateral stitching. Herein, we present the in situ growth of graphene and h-BN lateral heterostructures with tunable morphologies that range from a regular hexagon to highly symmetrical star-like structure on the surface of liquid Cu. The chemical vapor deposition (CVD) method is used, where the growth of the h-BN is demonstrated to be highly templated by the graphene. Furthermore, large-area production of lateral G-h-BN heterostructures at the centimeter scale with uniform orientation is realized by precisely tuning the CVD conditions. We found that the growth of h-BN is determined by the initial graphene and symmetrical features are produced that demonstrate heteroepitaxy. Simulations based on the phase field and density functional theories are carried out to elucidate the growth processes of G-h-BN flakes with various morphologies, and they have a striking consistency with experimental observations. The growth of a lateral G-h-BN heterostructure and an understanding of the growth mechanism can accelerate the construction of various heterostructures based on 2D materials

Monoclonal antibody induced with inactived EV71-Hn2 virus protects mice against lethal EV71-Hn2 virus infection

<p>Abstract</p> <p>Background</p> <p>Enterovirus 71 (EV71) is a viral pathogen that belongs to the <it>Picornaviridae </it>family, EV71-infected children can develop severe neurological complications leading to rapid clinical deterioration and death.</p> <p>Results</p> <p>In this study, several monoclonal antibodies (MAbs) were produced by immunizing mice with the inactived EV71 Henan (Hn2) virus strain. The isolated MAbs were characterised by <it>in vitro </it>neutralizing analysis and peptide ELISA. ELISA assay showed that the neutralizing monoclonal antibody 4E8 specifically reacted with synthetic peptides which contain amino acid 240-250 and 250-260 of EV71 VP1. The <it>in vivo </it>protection assay showed that 4E8 can protect two-day-old BALB/c mice against the lethal challenge of EV71 virus.</p> <p>Conclusion</p> <p>The MAb 4E8 could be a promising candidate to be humanized and used for treatment of EV71 infection.</p

Measurement of w-InN/h-BN Heterojunction Band Offsets by X-Ray Photoemission Spectroscopy

X-ray photoelectron spectroscopy has been used to measure the valence band offset (VBO) of the w-InN/h-BN heterojunction. We find that it is a type-II heterojunction with the VBO being −0.30 ± 0.09 eV and the corresponding conduction band offset (CBO) being 4.99 ± 0.09 eV. The accurate determination of VBO and CBO is important for designing the w-InN/h-BN-based electronic devices

SMG1 and NIK regulate apoptosis induced by Smac mimetic compounds

Smac mimetic compounds (SMCs) are experimental small molecules that induce tumour necrosis factor alpha (TNFα)-dependent cancer cell death by targeting the inhibitor of apoptosis proteins. However, many cancer cell lines are resistant to SMC-mediated apoptosis despite the presence of TNFα. To add insight into the mechanism of SMC-resistance, we used functional siRNA-based kinomic and focused chemical screens and identified suppressor of morphogenesis in genitalia-1 (SMG1) and NF-κB-inducing kinase (NIK) as novel protective factors. Both SMG1 and NIK prevent SMC-mediated apoptosis likely by maintaining FLICE inhibitory protein (c-FLIP) levels to suppress caspase-8 activation. In SMC-resistant cells, the accumulation of NIK upon SMC treatment enhanced the activity of both the classical and alternative nuclear factor-κB pathways, and increased c-FLIP mRNA levels. In parallel, persistent SMG1 expression in SMC-resistant cells repressed SMC-mediated TNFα-induced JNK activation and c-FLIP levels were sustained. Importantly, SMC-resistance is overcome by depleting NIK and SMG1, which appear to facilitate the downregulation of c-FLIP in response to SMC and TNFα treatment, leading to caspase-8-dependent apoptosis. Collectively, these data show that SMG1 and NIK function as critical repressors of SMC-mediated apoptosis by potentially converging on the regulation of c-FLIP metabolism