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Smart antennas have received great attention for their potentials to enable communication and perception functions at the same time. However, realizing the function synthesis remains an open challenge, and most existing system solutions are limited to narrow operating bands and high complexity and cost. Here, we propose an externally perceivable leaky-wave antenna (LWA) based on spoof surface plasmon polaritons (SSPPs), which can realize adaptive real-time switching between the “radiating” and “non-radiating” states and beam tracking at different frequencies. With the assistance of computer vision, the smart SSPP-LWA is able to detect the external target user or jammer, and intelligently track the target by self-adjusting the operating frequency. The proposed scheme helps to reduce the power consumption through dynamically controlling the radiating state of the antenna, and improve spectrum utilization and avoid spectrum conflicts through intelligently deciding the radiating frequency. On the other hand, it is also helpful for the physical layer communication security through switching the antenna working state according to the presence of the target and target beam tracking in real time. In addition, the proposed smart antenna can be generalized to other metamaterial systems and could be a candidate for synaesthesia integration in future smart antenna systems.

With the rapid growth of information flux, integrating more channels in limited spaces has been a critical requirement for highly-integrated long-range parallel transmissions. Although meta-waveguides, such as spoof surface plasmon polariton (SSPP) waveguides, can suppress crosstalk between adjacent channels, it is still urgent to seek new methods to further increase the number of channels without occupying additional space. Here, we propose a reconfigurable dual-mode meta-waveguide (RDMMW) by integrating diodes into meta-units, which supports two independent channels using two orthogonal modes. The RDMMW can be switched among dual-mode, even-mode, odd-mode and cutoff states by controlling the diodes, which provides more freedom to manipulate the channel features. The RDMMW possess two outstanding merits in highly-integrated long-range parallel transmissions, including lower coupling between two channels than conventional single-mode waveguides and constant mode coupling in longer waveguides. Thus the proposed RDMMW has advantages of multi-mode, reconfiguration, low coupling and high integration density, providing a new avenue to realize highly-integrated multi-functional systems.

Abstract Intercellular communication often relies on exosomes as messengers and is critical for cancer metastasis in hypoxic tumor microenvironment. Some circular RNAs (circRNAs) are enriched in cancer cell‐derived exosomes, but little is known about their ability to regulate intercellular communication and cancer metastasis. Here, by systematically analyzing exosomes secreted by non‐small cell lung cancer (NSCLC) cells, a hypoxia‐induced exosomal circPLEKHM1 is identified that drives NSCLC metastasis through polarizing macrophages toward to M2 type. Mechanistically, exosomal circPLEKHM1 promoted PABPC1‐eIF4G interaction to facilitate the translation of the oncostatin M receptor (OSMR), thereby promoting macrophage polarization for cancer metastasis. Importantly, circPLEKHM1‐targeted therapy significantly reduces NSCLC metastasis in vivo. circPLEKHM1 serves as a prognostic biomarker for metastasis and poor survival in NSCLC patients. This study unveils a new circRNA‐mediated mechanism underlying how cancer cells crosstalk with macrophages within the hypoxic tumor microenvironment to promote metastasis, highlighting the importance of exosomal circPLEKHM1 as a prognostic biomarker and therapeutic target for lung cancer metastasis.

Intracerebral hemorrhage is a life-threatening condition with a high fatality rate and severe sequelae. However, there is currently no treatment available for intracerebral hemorrhage, unlike for other stroke subtypes. Recent studies have indicated that mitochondrial dysfunction and mitophagy likely relate to the pathophysiology of intracerebral hemorrhage. Mitophagy, or selective autophagy of mitochondria, is an essential pathway to preserve mitochondrial homeostasis by clearing up damaged mitochondria. Mitophagy markedly contributes to the reduction of secondary brain injury caused by mitochondrial dysfunction after intracerebral hemorrhage. This review provides an overview of the mitochondrial dysfunction that occurs after intracerebral hemorrhage and the underlying mechanisms regarding how mitophagy regulates it, and discusses the new direction of therapeutic strategies targeting mitophagy for intracerebral hemorrhage, aiming to determine the close connection between mitophagy and intracerebral hemorrhage and identify new therapies to modulate mitophagy after intracerebral hemorrhage. In conclusion, although only a small number of drugs modulating mitophagy in intracerebral hemorrhage have been found thus far, most of which are in the preclinical stage and require further investigation, mitophagy is still a very valid and promising therapeutic target for intracerebral hemorrhage in the long run.

In ventilation systems of metal mines, the real-time measurement of the airflow field and a reduction in pollutants are necessary for clean environmental management and human health. However, the limited quantitative data and expensive detection technology hinder the accurate assessment of mine ventilation effectiveness and safety status. Therefore, we propose a new method for constructing a mine intelligent ventilation system with a global scheme, which can realize the intelligent prediction of unknown points in the mine ventilation system by measuring the airflow parameters of multiple known points. Firstly, the nodal wind pressure method combined with the Hardy–Cross iterative algorithm is used to solve the mine ventilation network, and the airflow parameters under normal operation and extreme working conditions are simulated, based on which an intelligent ventilation training database is established. Secondly, we compared the airflow parameter prediction ability of three different machine learning models with different neural network models based on the collected small-sample airflow field dataset of a mine roadway. Finally, the depth learning method is optimized to build the intelligent algorithm model of the mine ventilation system, and a large number of three-dimensional simulation data and field measurement data of the mine ventilation system are used to train the model repeatedly to realize the intelligent perception of air flow parameters of a metal mine ventilation network and the construction of an intelligent ventilation system. The results show that the maximum error of a single airflow measurement point is 1.24%, the maximum overall error is 3.25%, and the overall average error is 0.51%. The intelligent algorithm has a good model training effect and high precision and can meet the requirements of the research and application of this project. Through case analysis, this method can predict the airflow parameters of any position underground and realize the real-time control of mine safety.

The authors present an intelligent metasurface system that uses a target detection algorithm combined with a depth camera, to automatically detect the position of moving targets and achieve real-time wireless communications. The system can operate for multiple targets in limited ambient light, outdoor and other realistic environments.

BackgroundDomestic waste classification is one of the major livelihood projects in China. With the introduction of the Shanghai Household Waste Management Regulation in 2019, the work of domestic waste classification has been carried out nationwide, yet its potential risks especially those derived from microorganisms are not clear. ObjectiveTo investigate the microbial characteristics of the domestic waste in typical residential areas in Shanghai, and provide a theoretical basis for health protection during the domestic waste classification process in Shanghai and throughout China. MethodsDry and wet waste from a typical residential community in Shanghai were collected during 2019–2020. Microbial colonies were counted in domestic waste and analyzed for growth patterns. Then through 16S rRNA sequencing using lllumina PE250, hierarchical clustering analysis was conducted to reveal the similarity and dissimilarity of community compositions in different domestic waste groups, alpha diversity was estimated to reflect the richness and diversity of bacterial communities, principal co-ordinates analysis of unweighted UniFrac distance was performed to estimate the beta diversity, and linear discriminant analysis effect size (LEfSe) was used to find features differentially represented among domestic waste groups. ResultsIn the chosen typical residential community of this study, the numbers of microorganisms in waste were quite different, with lower numbers of microorganisms in dry waste than the numbers in wet waste. In addition, different growth curves of microorganisms were shown for different seasons, and the peak baterial colony numbers were 200 CFU·cm−2, 6×105 CFU·mL−1, 10 CFU·cm−2, and 2×106 CFU·mL−1 for summer dry waste, summer wet waste, winter dry waste, and winter wet waste, respectively. The results of 16S RNA demonstrated significant differences in α and β diversity indicators among different waste groups, and the difference in waste classifications was larger than the difference of the same classification of waste in different seasons. The main compositions of bacterial colonies in domestic waste was Proteobacteria, followed by Firmicute and Bacteroidota. The clustering analysis showed that the microbial composition in summer dry waste was close to that in winter dry waste, while other groups were quite different. In total 48 differential bacterial taxa were found at the level of genus including Pseudomonas and Pantoea. ConclusionDifferent seasons and different classifications of domestic waste present varied microbial characteristics, with different potential pathogenic microorganisms. Together with other related studies, we suggest that different measures should be taken for different domestic wastes to prevent and control the health hazards associated with waste classification.

The Airy beam has intrigued long-held research interests and developed various striking applications attributed to the unprecedented diffraction-free, self-bending and self-healing properties. Metasurfaces with superior design freedom and small structure size open a fire-new avenue for generating efficient and broadband Airy beam. Nevertheless, most existing Airy beam generators can only respond to one polarization state of electromagnetic waves and produce the single Airy beam, which immensely limit the serviceability and utilization of the Airy beam generators. Herein, an inspiring strategy of multichannel Airy beam generator based on the multichannel amplitude and phase controlled metasurface is proposed to independently generate the Airy beams for linear polarized waves in 20–24 GHz and orthogonal circular polarized waves in 12–14 GHz and 15–17 GHz. Notably, an appealing paradigm of multichannel beam focusing can be realized by the integrated multichannel Airy beam generator, which possesses strong ability to circumvent the obstacle owing to the self-healing feature of the Airy beam. A proof-of-concept prototype is constructed to verify the feasibility of our methodology, and multitudinous simulations and experiments are in excellent accordance with our theoretical predictions. This novel design of multichannel Airy beam generator will have tremendous application potential in sensing, communication and other multifunctional metadevices.

Holography has been continuously spurring tremendous interest of researchers attributed to its unparalleled capability of photographically reconstructing the desired images. Based on the metasurfaces with multiple degrees of freedom, multiplexing meta-holograms are experiencing the research upsurge because of enormous application potential. However, existing multiplexing meta-holograms cannot tailor the amplitude information, and possess limited imaging channels and high channel crosstalk, which hinder the improvement of information capacity and imaging quality of multiplexing meta-holograms. Herein, an innovative multiplexing meta-hologram based on the helicity-assisted meta-atoms is proposed, which can perfectly reconstruct four independent images by altering the working frequency, polarization state and propagation direction of incident waves, and theoretically realize the holography in sixteen different channels by easily rotating, mirroring, and arranging the structures of meta-atoms. Numerous simulations and experiments collectively corroborate the feasibility of our methodology, and the quantitative analyses verify the high fidelity of the reconstructed images, which results from the low crosstalk between the amplitude modulation and phase modulation in different imaging channels. This inspiring strategy of multiplexing meta-hologram with large channel capacity and high imaging quality will have promising application prospects in information display, storage and encryption, and provide an alternative path for the design of multifunctional microwave devices.

Metamaterials (MTMs) are artificial structures characterized by flexible and designable electromagnetic (EM) properties, including permittivity, permeability, and refractive index. Because of their subwavelength‐scale composing units, MTMs are able to manipulate the propagation of EM waves at extremely fine resolutions and offer solutions for new‐concept devices and components with novel functionalities and challenge‐breaking properties. From among the attractive applications of MTMs, this review article focuses on MTM lenses (also termed metalenses) developed in recent years for the purpose of microwave engineering, including beam forming, beam steering, and imaging. Bulk lenses made of 3D MTMs and planar lenses made of 2D transmission‐type metasurfaces are both involved and investigated. Different categories of metalenses, together with the theory, principles, methods, and advantages of their designs, are introduced and discussed. Potential and future applications of metalenses at microwave frequencies are also presented.

Spoof surface plasmon polaritons (SPPs) are highly localized surface waves that can be supported on metal surfaces with subwavelength decorations. Mode matching and momentum matching have been investigated so as to efficiently excite the spoof SPPs through conventional planar waveguides (WGs) such as the microstrip (MS) line and the co-planar waveguide (CPW). In this work, a smooth and wideband bridge between the conventional rectangular waveguide and the plasmonic waveguide of spoof SPPs has been proposed and experimentally demonstrated. High efficiency is achieved in both simulation and experiment in a wide frequency range from 12 to 18 GHz. The high-efficiency and broadband excitation of spoof SPPs through rectangular waveguide has great potentials in microwave, millimeter-wave and terahertz circuits, and systems.

As-cast and as-extruded Mg-[x]Zn-0.3Mn (x=1.5, 2.0 wt.%) alloys were prepared by means of medium-frequency induction-heating technique and extrusion process, respectively. The microstructural characteristics, thermal conductivity and mechanical properties of the samples were characterized. The research results show that the samples are composed of major α-Mg and minor second phases MgZn2. For the as-extruded samples, the grain size is refined. After extrusion, much more second phases were precipitated from α-Mg matrix and the dislocations were reduced. The degree of lattice distortion was decreased for as-extruded samples. Because of the decline of lattice distortion degree, the as-extruded samples display much higher thermal conductivity than the as-cast samples. Additionally, on account of lower lattice distortion, Mg-1.5Zn-0.3Mn alloy has a bit larger thermal conductivity than Mg-2Zn-0.3Mn alloy. Finally, the as-extruded alloys present good mechanical properties based on the fine-grained strengthening and second-phase strengthening mechanism.

We propose a method to design a transmission-spectrum-controllable spoof surface plasmon polaritons (SPPs) based on the interaction between spoof SPP waveguide and frequency tunable metamaterial (MTM) particles. To achieve the tunable MTM particles, we introduce varactor-diodes into split-ring resonators (SRRs). Taking the advantage of sub-wavelength scale of SRRs, we design and fabricate a compact transmission-spectrum-controllable spoof SPPs. Both simulated and measured results demonstrate excellent dynamic control of transmission coefficients at microwave frequencies. [ABSTRACT FROM AUTHOR]

Transformation optics has led the way in the development of electromagnetic invisibility cloaks from science fiction to engineering practice. Invisibility cloaks have been demonstrated over a wide range of the electromagnetic spectrum, and with a variety of different fabrication techniques. However, all previous schemes have relied on the use of metamaterials consisting of arrays of sub-wavelength inclusions. We report on the first cloaking structure made of a high-κ dielectric-loaded foam mixture. A polyurethane foam mixed with different ratios of barium titanate is used to produce the required range of permittivities, and the invisibility cloak is demonstrated to work for all incident angles over a wide range of microwave frequencies. This method will greatly facilitate the development and large-scale manufacture of a wide range of transformation optics-based structures. [ABSTRACT FROM AUTHOR]