Reconfigurable intelligent surfaces (RIS) is a promising solution to build a programmable wireless environment via steering the incident signal in fully customizable ways with reconfigurable passive elements. In this paper, we consider a RISaided multiuser multiple-input single-output (MISO) downlink communication system. Our objective is to maximize the weighted sum-rate (WSR) of all users by joint designing the beamforming at the access point (AP) and the phase vector of the RIS elements, while both the perfect channel state information (CSI) setup and the imperfect CSI setup are investigated. For perfect CSI setup, a low-complexity algorithm is proposed to obtain the stationary solution for the joint design problem by utilizing the fractional programming technique. Then, we resort to the stochastic successive convex approximation technique and extend the proposed algorithm to the scenario wherein the CSI is imperfect. The validity of the proposed methods is confirmed by numerical results. In particular, the proposed algorithm performs quite well when the channel uncertainty is smaller than 10%.Index Terms-Reconfigurable intelligent surfaces (RIS), passive radio, multiple-input-multiple-output (MIMO), fractional programming, stochastic successive convex approximation.

In this paper, we introduce an intelligent reflecting surface (IRS) to provide a programmable wireless environment for physical layer security. By adjusting the reflecting coefficients, the IRS can change the attenuation and scattering of the incident electromagnetic wave so that it can propagate in a desired way toward the intended receiver. Specifically, we consider a downlink multiple-input single-output (MISO) broadcast system where the base station (BS) transmits independent data streams to multiple legitimate receivers and keeps them secret from multiple eavesdroppers. By jointly optimizing the beamformers at the BS and reflecting coefficients at the IRS, we formulate a minimum-secrecy-rate maximization problem under various practical constraints on the reflecting coefficients. The constraints capture the scenarios of both continuous and discrete reflecting coefficients of the reflecting elements. Due to the non-convexity of the formulated problem, we propose an efficient algorithm based on the alternating optimization and the path-following algorithm to solve it in an iterative manner. Besides, we show that the proposed algorithm can converge to a local (global) optimum. Furthermore, we develop two suboptimal algorithms with some forms of closed-form solutions to reduce the computational complexity. Finally, the simulation results validate the advantages of the introduced IRS and the effectiveness of the proposed algorithms.Index Terms-Intelligent reflecting surface, programmable wireless environment, physical layer security, beamforming.

MnO x /Al 2 O 3 catalysts (i.e., impregnating manganese oxide on alumina) were employed to remove elemental mercury (Hg 0 ) from flue gas. MnO x /Al 2 O 3 was found to have significant adsorption performance on capturing Hg 0 in the absence of hydrogen chloride (HCl), and its favorable adsorption temperature was about 600 K. However, the catalytic oxidation of Hg 0 became dominant when HCl or chlorine (Cl 2 ) was present in flue gas, and the removal efficiency of Hg 0 was up to 90% with 20 ppm of HCl or 2 ppm of Cl 2 . In addition, the catalysts with adsorbed mercury could be chemically regenerated by rinsing with HCl gas to strip off the adsorbed mercury in the form of HgCl 2 . Sulfur dioxide displayed inhibition to the adsorption of Hg 0 on the catalysts, but the inhibition was less to the catalytic oxidation of Hg 0 , especially in the presence of Cl 2 . The analysis results of XPS and pyrolysis-AAS indicated that the adsorbed mercury was mainly in the forms of mercuric oxide (HgO) and the weakly bonded speciation, and the ratio of them varied with the adsorption amount and manganese content on catalysts. The multifunctional performances of MnO x /Al 2 O 3 on the removal of Hg 0 appeared to be promising in the industrial applications.

Photodynamic therapy (PDT) still faces a key challenge associated with its oxygen-dependent property, which limits its therapeutic efficiency against hypoxic tumor. To address the problem, covalent organic nanosheets (CONs) are prepared with a donor–acceptor molecular heterostructure. CONs can address the hypoxic-tumor PDT by two strategies, that is, type I PDT and type I PDT combined with photothermal therapy (PTT). On the one hand, the molecular heterostructure of CONs can afford highly efficient charge carrier separation, a long lifetime of electrons and holes can be obtained, the electrons can reduce O2 to form O2 ·–, and at the same time, the holes can oxidize water to produce ·OH. Therefore, type I PDT is obtained, which can be used to diminish the limits of hypoxia in type II PDT. On the other hand, the recombination of photoexcited species results in an important nonradiative attenuation, and thus the energy is emitted as heat. A combination of type I PDT and PTT serves as an effective way to get around the difficulties of hypoxia in PDT. Intravenous injection of CONs in nude mice followed by the combination of type I PDT and PTT under single-wavelength irradiation achieves significant tumor ablation.

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β-Sitosterol is a well known phytosterol in plants, but owing to its poor solubility in typical media, determining its cellular mechanisms has been proven to be difficult. In this study, we investigated the anti-inflammatory activity of βsitosterol (BSS) isolated from Moringa oleifera in two cell lines. Over a dose range of 7.5 to 30 μM, BSS dispersed well in the medium as nanoparticles with diameters of 50 ± 5 nm and suppressed the secretion of inflammatory factors from keratinocytes and macrophages induced by PGN, TNF-α, or LPS, such as TNF-α, IL-1β, IL-6, IL-8, and ROS, separately. In addition, BSS significantly reduced the expression of NLRP3, a key component of NLRP3 inflammasomes, and inhibited the activation of caspase-1. There was partial inhibition of NF-κB in macrophages. This is the first study to report an increase in the solubility of nearly water-insoluble phytosterols via the formation of nanoparticles and to delineate the formulation's capacity to inhibit the signal transduction pathways of inflammation in macrophages.

During mobile edge computing, due to the movement of nodes and the exhaustion of node energy, link failure occurs thus reducing the network lifetime in the mobile ad-hoc network. When the route fails, because the single-path protocols need to restart the route discovery process, the delay of the network is greatly increased. Therefore, the multi-path routing protocol is proposed, saving the cost of route discovery. In this paper, we propose an ad hoc on-demand multi-path distance vector (AOMDV) routing protocol based on link lifetime and energy consumption prediction (named LLECP-AOMDV) for mobile edge computing. In the route discovery phase, the energy grading strategy is adopted. When the node energy is lower than the threshold, it no longer participates in the route discovery. In the routing selected phase, the path is selected based on the lifetime of the route link and the minimum energy consumption of the route. According to energy consumption, packet delivery rate, end-to-end delay performance indicators, we evaluate the comparison results. The result shows that under most network performance indicators and parameters, the proposed LLECP-AOMDV is superior to the other three protocols, which improves the network lifetime, reduces the node's energy consumption and the average end-to-end delay. The protocol is very useful for mobile edge computing. INDEX TERMS Mobile edge computing, MANET, AOMDV, energy threshold, link lifetime, energy consumption.

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