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The digital and programmable metasurfaces, as opposed to conventional metasurfaces, offer a more sophisticated method of collaborating information and physics, showcasing several real-time controls to electromagnetic (EM) ways in succinct ways. In this work, we propose a multi-frequency amplitude-programmable (MFAP) metasurface with multiple frequency channels to enhance the presentation and manipulation of EM data. With this metasurface, the reflected amplitudes can be simultaneously and independently encoded between high (digit “1”) and low (digit “0”) levels. The amplitude code is unique, which exhibits both reflection coefficients and radiation patterns to allow for flexible multi-functional EM operations with frequency. For instance, the MFAP metasurface can be used to design innovative communication systems by transmitting various EM signals individually across the channels in time domain. It is also possible to carry out multi-bit transmissions by mixing these frequency channels. By introducing complex coding patterns in space domain, it is possible to manipulate EM powers with greater precision. A square-split ring meta-atom that can achieve stable single-frequency amplitude control and multi-frequency 1 bit amplitude-programmable features is described as a proof-of-concept. Varactors loaded on metallic structures of various sizes are switched between operating states to modify the amplitude codes at each frequency channel. The suggested MFAP metasurface’s validity is confirmed by simulations and measurements from a dual-channel MFAP metasurface prototype.

Context Urolithin A (UroA) can inhibit the growth of many human cancer cells, but it has not be reported if UroA inhibits nasopharyngeal carcinoma (NPC) cells.Objective To explore the inhibitory effect of UroA on NPC and potential mechanism in vitro.Materials and methods RNA-sequencing-based mechanistic prediction was conducted by comparing KEGG enrichment of 40 μM UroA-treated for 24 h with untreated CNE2 cells. The untreated cells were selected as control. After NPC cells were treated with 20–60 μM UroA, proliferation, migration and invasion of were measured by colony formation, wound healing and transwell experiments. Apoptosis, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) were measured by flow cytometry, Hoechst 33342, Rhodamine 123, JC-1 staining and ROS assay methods, respectively. Gene and protein expression were measured by RT-qPCR and Western blotting assay.Results RNA-sequencing and KEGG enrichment revealed UroA mainly altered the ECM receptor interaction pathway. UroA inhibited cells proliferation, epithelial–mesenchymal-transition pathway, migration and invasion with IC50 values of 34.72 μM and 44.91 μM, induced apoptosis, MMP depolarization and increase ROS content at a concentration of 40 μM. UroA up-regulated E-cadherin, Bax/Bcl-2, c-caspase-3 and PARP proteins, while inhibiting COL4A1, MMP2, MMP9, N-cadherin, Vimentin and Snail proteins at 20–60 μM. Moreover, co-treatment of UroA (40 μM) and NAC (5 mM) could reverse the effect of UroA on apoptosis-related proteins.Discussion and conclusions RNA-sequencing technology based on bioinformatic analyses may be applicable for studiying the mechanism of drugs for tumour treatment.

In light of the escalating demand for computing powers, wave‐based analog computers have emerged as a compelling study area due to their remarkable capacity for ultra‐fast operation. Here, a programmable wave‐based computer, based on programmable meta‐structures is proposed, which is also called as meta‐computer. The meta‐computer can perform various types of analog computations in real‐time in the electromagnetic (EM) wave space, including matrix‐vector multiplication, discrete Fourier transform, filtering, and solving complex matrix equations. Owing to the powerful capability of the programmable meta‐structures in manipulating the EM fields and waves in real‐time, the proposed meta‐computer exhibits the advantages of flexible re‐programmability, low complexity, and direct computation in the EM space. Two prototypes of the meta‐computer in the microwave frequency are designed and fabricated, and the computing capability is validated through both numerical simulations and experiments. This work contributes a prominent approach for fully programmable wave‐based computers with noteworthy implications for expanding the applications of analog computing. [ABSTRACT FROM AUTHOR]

Dual‐polarization programmable metasurfaces can flexibly manipulate electromagnetic (EM) waves while providing approximately twice the information capacity. Therefore, they hold significant applications in next‐generation communication systems. However, there are three challenges associated with the existing dual‐polarization programmable metasurfaces. This article aims to propose a novel design to address them. First, the design overcomes the challenge of element‐ and polarization‐independent controls, enabling more powerful manipulations of EM waves. Second, by using more energy‐efficient tunable components and reducing their number, the design can be nearly passive (maximum power consumption of 27.7 mW), leading to a significant decrease in the cost and power consumption of the system (at least two orders of magnitude lower than the power consumption of conventional programmable metasurfaces). Third, the design can operate in a broad bandwidth, which is attractive for practical engineering applications. Both the element and array of the metasurface are meticulously designed, and their performance has been carefully studied. The experiments demonstrate that 2D wide‐angle beam scanning can be realized. Moreover, secure communication based on directional information modulation can be implemented by exploiting the metasurface and an efficient discrete optimization algorithm, showing its programmable, multiplexing, broadband, green, and secure features. [ABSTRACT FROM AUTHOR]

A novel concept of "Cutoff gray‐level" is introduced for evaluation of MicroLED PWM pixel circuits at low gray‐level with consideration of gamma correction and device variation. Additionally, a cost‐effective two‐level dithering method is proposed and machine learning is used to establish its algorithm. This approach effectively deals with the issue of low grayscale performance in MicroLED displays driven by PWM. [ABSTRACT FROM AUTHOR]

With the increasing demands for computing powers, wave‐based computation has attracted researcher's attention due to its inherent high speed. Metasurfaces have flexible and powerful capabilities to manipulate electromagnetic waves and are good candidates for building a next‐generation of wave‐based computers. In this work, a computational‐metasurface‐based equation solver that yields real‐time solutions to arbitrary complex matrix equations (CME) in the form of K · x + c = 0 is proposed. Full‐wave simulations and experimental measurements are conducted to verify the functionality of the proposed solver. This work serves to provide a promising technique to overcome some shortcomings of the existing designs and lays the first stone of the bridge toward programmable wave‐space computers. [ABSTRACT FROM AUTHOR]

A digital coding metasurface is a platform connecting the digital space and electromagnetic wave space, and has therefore gained much attention due to its intriguing value in reshaping wireless channels and realizing new communication architectures. Correspondingly, there is an urgent need for electromagnetic information theory that reveals the upper limit of communication capacity and supports the accurate design of metasurface-based communication systems. To this end, we propose a macroscopic model and a statistical model of the digital coding metasurface. The macroscopic model uniformly accommodates both digital and electromagnetic aspects of the meta-atoms and predicts all possible scattered fields of the digital coding metasurface based on a small number of simulations or measurements. Full-wave simulations and experimental results show that the macroscopic model is feasible and accurate. A statistical model is further proposed to correlate the mutual coupling between meta-atoms with covariance and to calculate the entropy of the equivalent currents of digital coding metasurface. These two models can help reconfigurable intelligent surfaces achieve more accurate beamforming and channel estimation, and thus improve signal power and coverage. Moreover, the models will encourage the creation of a precoding codebook in metasurface-based direct digital modulation systems, with the aim of approaching the upper limit of channel capacity. With these two models, the concepts of current space and current entropy, as well as the analysis of information loss from the coding space to wave space, is established for the first time, helping to bridge the gap between the digital world and the physical world, and advancing developments of electromagnetic information theory and new-architecture wireless systems. [ABSTRACT FROM AUTHOR]

Information metasurfaces (IMSs) have been considered to be a revolutionary technology for improving the spectral efficiency of sixth‐generation (6G) wireless communications due to their superior ability to manipulate electromagnetic (EM) waves. However, there are still problems to be solved before the widespread application of IMSs. The first is to reduce power consumption, and the second is to achieve a long‐range remote control. In this paper, a long‐range and nearly passive radio frequency identification (RFID)‐controlled IMS is proposed. The proposed IMS comprises four RFID tags and 8 × 8 elements, each of which is integrated with a single‐pole‐double‐throw switch chip to achieve 1‐bit phase reconfigurability. With the remote control of the RFID system, the IMS can be programmed to switch between three functionalities, including beam splitting, beamforming, and EM‐wave absorption. Experiments are performed and the beam‐splitting functionality is demonstrated. The measurement results indicate that the wireless communication between the RFID reader and the IMS is robust within 21.7 m. Additionally, the power consumption of the IMS is as low as 0.576 mW, which can be negligible. The scheme presented in this paper paves the way for the large‐scale applications of IMSs in 6G wireless communications. [ABSTRACT FROM AUTHOR]

The photonic spin Hall effect (SHE) arises from the spin–orbit interaction of lights and plays an important role in light–matter interactions. The phenomenon of spin‐momentum locking validates photonic SHE with unprecedented abilities in wave manipulation. Here, the directional coupling and spin‐momentum locking in spoof surface plasmon polaritons (SSPP) are demonstrated. The transverse spin angular momentum in SSPP is calculated using effective medium theory and the study shows the spin direction is inherently locked to the propagation direction, thus manifesting the spin–orbit interaction of electromagnetic (EM) waves. The spin‐momentum locking is further verified by projecting linearly and circularly polarized waves onto a scatterer‐SSPP structure. It is observed that the helicity of the incident EM wave governs the propagation direction of excited SSPP modes and the directional coupling originates from constructive and destructive interferences of two orthogonal modes. Reconfigurable transmissions of SSPPs are further demonstrated. The proposed design can find applications in reconfigurable sensors, antennas, and power dividers. This approach demonstrates the spin‐momentum locking in SSPPs and introduces new degrees of freedom to manipulate SSPPs by engineering the helicity and interference of EM waves. [ABSTRACT FROM AUTHOR]