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Vision plays a peculiar role in intelligence. Visual information, forming a large part of the sensory information, is fed into the human brain to formulate various types of cognition and behaviours that make humans become intelligent agents. Recent advances have led to the development of brain-inspired algorithms and models for machine vision. One of the key components of these methods is the utilization of the computational principles underlying biological neurons. Additionally, advanced experimental neuroscience techniques have generated different types of neural signals that carry essential visual information. Thus, there is a high demand for mapping out functional models for reading out visual information from neural signals. Here, we briefly review recent progress on this issue with a focus on how machine learning techniques can help in the development of models for contending various types of neural signals, from fine-scale neural spikes and single-cell calcium imaging to coarse-scale electroencephalography (EEG) and functional magnetic resonance imaging recordings of brain signals.

Esophageal squamous cell carcinoma (ESCC) is a malignant tumor that commonly occurs worldwide. Usually, Asia, especially China, has a high incidence of esophageal cancer. ESCC often has a poor outcome because of a late diagnosis and lack of effective treatments. To build foundations for the early diagnosis and treatment of ESCC, we used the gene expression datasets GSE20347 and GSE17351 from the GEO database and a private dataset to uncover differentially expressed genes (DEGs) and key genes in ESCC. Notably, we found that replication factor C subunit 4 (RFC4) and guanine monophosphate synthase (GMPS) were upregulated but have been rarely studied in ESCC. In particular, to the best of our knowledge, our study is the first to explore GMPS and ESCC. Furthermore, we found that high levels of RFC4 and GMPS expression may result from an increase in DNA copy number alterations. Furthermore, RFC4 and GMPS were both upregulated in the early stage and early nodal metastases of esophageal carcinoma. The expression of RFC4 was strongly correlated with GMPS. In addition, we explored the relationship between RFC4 and GMPS expression and tumor-infiltrating immune cells (TILs) in esophageal carcinoma. The results showed that the levels of RFC4 and GMPS increased with a decrease in some tumor-infiltrating cells. Upregulated RFC4 and GMPS with high TILs indicate a worse prognosis. In summary, our study shows that RFC4 and GMPS have potential as biomarkers for the early diagnosis of ESCC and may played a crucial role in the process of tumor immunity in ESCC.

Gradient metasurfaces have been extensively applied in the unprecedented control of light beams over thin optical components. However, these metasurfaces suffer from low efficiency when bending light through large angles and high fabrication demand when it requires fine discretion. In this work, we investigate all-dielectric metagratings based on the generalized Kerker effect induced by interference between Mie-type resonances. It allows extraordinary optical diffraction for beam steering through ultralarge angles. The coupling inside and between the lattices in the metagrating can be used to tune the excited states of the electric and magnetic resonances, including both the fundamental dipoles and high-order multipoles, leading to an ideal asymmetrical scattering pattern that redistributes the energy between the diffraction channels as required. The quadrupole and hexadecapole not only significantly enhance the working efficiency but also enable distinctive possibilities for wave manipulation that cannot be reached by dipoles. Utilizing a thin array of silicon rods, large-angle negative refraction and reflection are realized with almost unity efficiency under both transverse magnetic and transverse electric polarization. Compared with conventional metasurfaces, such an all-dielectric metagrating has the merits of high flexibility, high efficiency, and low fabrication requirements. The coupling and interactions among the multipoles may serve as a foundation for various forms of on-chip optical wave control.

Recent advances in spoof surface plasmon (SSP) have offered enormous opportunities for engineering electromagnetic waves at the subwavelength scale. However, the fundamental limitation of the extremely finite space channels on exciting SSP challenges their practical applications. Here, to the best of our knowledge, a new method that can realize high-efficiency infinite-channel SSP excitation based on hyperbolic plasmonic metasurfaces is proposed. Free-space propagating waves impinging from arbitrary directions can be coupled to SSP owing to the theoretical perfect wave vector match between the modulated incident waves and the hyperbolic plasmonic metasurfaces. A proof-of-method metacoupler working at 8 GHz is designed and fabricated with the novel functionality numerically and experimentally verified by the consistent guide wavelength with theory. Further experimental investigation reveals a total coupling efficiency exceeding 50% for the impinging waves with incidence angles ranging from −44° to 44°. The proposed methodology provides a new route to design multichannel antennas and detectors.

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors in China. However, there are no targets to treat ESCC because the molecular mechanism behind the cancer is still unclear. Here, we found a novel long noncoding RNA LINC02820 was upregulated in ESCC and associated with the ESCC clinicopathological stage. Through a series of functional experiments, we observed that LINC02820 only promoted the migration and invasion capabilities of ESCC cell lines. Mechanically, we found that LINC02820 may affect the cytoskeletal remodeling, interact with splice factor 3B subunit 3 (SF3B3), and cooperate with TNFα to amplify the NF-κB signaling pathway, which can lead to ESCC metastasis. Overall, our findings revealed that LINC02820 is a potential biomarker and therapeutic target for the diagnosis and treatment of ESCC.

Breaking the diffraction limit is always an appealing topic due to the urge for a better imaging resolution in almost all areas. As an effective solution, the superlens based on the plasmonic effec...

The aldo‐keto reductases family 1 member C2 (AKR1C2) has critical roles in the tumorigenesis and progression of malignant tumours. However, it was also discovered to have ambiguous functions in multiple cancers and till present, its clinical significance and molecular mechanism in oesophageal squamous cell carcinoma (ESCC) has been unclear. The aim of this study was to explore the role of AKR1C2 in the tumorigenesis of ESCC. Here, we showed that AKR1C2 expression was found to be up‐regulated in ESCC tissues and was significantly associated with pathological stage, lymph node metastasis and worse outcomes. Functional assays demonstrated that an ectopic expression of AKR1C2 in ESCC cells resulted in increased proliferation, migration and cisplatin resistance, while knockdown led to inversing effects. Bioinformation analyses and mechanistic studies demonstrated that AKR1C2 activated the PI3K/AKT signalling pathway, furthermore, the inhibitor of PI3K or the selective inhibitor of AKR1C2 enzyme activity could reverse the aggressiveness and showed synergistic antitumour effect when combined with cisplatin, both in vitro and in vivo. In conclusion, Our findings revealed that AKR1C2 could function as an oncogene by activating the PI3K/AKT pathway, as a novel prognostic biomarker and/or as a potential therapeutic target to ESCC.

A 1 bit single-polarization broadband space-time-coding digital metasurface element with a zero cross polarization is proposed. This element consists of a modified patch, an electronic switch, a dc-bias network, a ground plane, and two-layer dielectrics. The upper patch with edge loading and centered square hole is fully optimized to achieve broadband and stable phase difference between two states. By electronically controlling the diode, the element achieves a 1 bit phase shift with a relative bandwidth of 20% within 180° ± 30° from 7.71 to 9.43 GHz. Moreover, a negligible cross polarization is obtained due to the uniaxial symmetry of the structure, and the amplitude loss is less than 0.8 dB for two states. The experimental results measured in a rectangular waveguide are well matched with the simulations, further demonstrating validity of the proposed element.

Terahertz biosensing provides a suitable method to identify biomolecules due to their rich spectral fingerprint in this electromagnetic region. However, owing to the limitations of terahertz sources and detectors, the signal is weak and requires to be enhanced by particular technologies. In this paper, we propose a terahertz plasmonic biosensor based on Goos-Hanchen effect in graphene. Sample sensing can be realized by measuring the Goos-Hanchen shift of the reflected light. Numerical simulations show that the sensitivity of this biosensor can reach a high value up to $2.5\times 10^4\mu$ m/RIU. This graphene plasmonic configuration combined with Goos-Hanchen effect provides a novel high-sensitivity approach for future terahertz biosensing applications.

In this work, we propose an angle-independent beam splitter based on spoof surface plasmon. Arbitrary incident waves can be divided in half, and scatter towards two specific and independent directions. The proposed beam splitter consists of the upper periodic metal cylinder and the metal grating below. The former is placed to modulate the incident wave and the spoof surface plasmon with the specified wave vector, and the latter is used to support the excited spoof surface plasmon. To verify the proposed functionalities, we design three beam splitters with different splitter angles and calculate their field distributions under the illumination of the same Gaussian beam. The ideal numerical results agree well with the theory.

Spoof surface plasmons (SSPs) can manipulate electromagnetic waves with subwavelength prints, which offers possibilities for many applications. To generate the SSPs propagating on a two-dimensional (2D) scale, the all-dielectric or dielectric-metal metasurfaces are generally exploited. However, the power capacity of the all-dielectric or dielectric-metal metasurfaces is relatively low. In this work, a 2D groove metal array is utilized to generate the SSPs. The dimension of the grooves is changed to possess the SSPs propagating on it. Based on this principle, a 2D half-Maxwell-fisheye lens is proposed utilizing the groove metal array, on which a spot on one side of the lens can diverge to a plane wave on the exit facet in the simulation. The all-metal half-Maxwell-fisheye lens is capable to be employed for high-power application scenarios.

Hong-Fa Xu,1,2,* Tie-Jun Huang,3,* Qin Yang,1 Liang Xu,1 Fen Lin,1 Yan-Hong Lang,1 Hao Hu,4 Li-Xia Peng,1 Dong-Fang Meng,1 Yu-Jie Xie,1 Li Tan,5 Chao-Nan Qian,1 Bi-Jun Huang11Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou 510060, People’s Republic of China; 2Zhuhai Precision Medical Center, Zhuhai People’s Hospital Affiliated to Jinan University, Zhuhai 519000, People’s Republic of China; 3Department of Nuclear Medicine, The Second People’s Hospital of Shenzhen, Shenzhen 518035, People’s Republic of China; 4Department of Traditional Chinese Medicine, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510060, People’s Republic of China; 5Center of Hematology, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510230, People’s Republic of China*These authors contributed equally to this work Background/Aims: The tumor-suppressive functions of interferon regulatory factor 6 (IRF6) in some tumors have been preliminarily established, but its pathogenesis and underlying molecular mechanisms in breast cancer, the most common malignancy in women, remains poorly understood.Methods: Pairs of typical breast cancer cell lines (high- and low-aggressive) in addition to 27 breast cancer tissue samples and 31 non-cancerous breast tissues were used to investigate the expression level of IRF6 and Lentivirus-mediated gain-of-function studies, short hairpin RNA-mediated loss-of-function studies in vivo and in vitro were used to validate the role of IRF6 in breast cancer. Next, we performed RNA-Seq analysis to identify the molecular mechanisms of IRF6 involved in breast cancer progression.Results: Our findings showed that IRF6 was downregulated in highly invasive breast cancer cell lines but upregulated in poorly aggressive ones. Functional assays revealed that elevated IRF6 expression could suppress cell proliferation and tumorigenicity, and enhanced cellular chemotherapeutic sensitivity. To identify the molecular mechanisms involved, we performed a genome-wide and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis in breast cancer cells using RNA sequencing of gene expression profiles following the overexpression of IRF6. Genome-wide and KEGG analyses showed that IRF6 might mediate the PI3K-regulatory subunit PIK3R2, which in turn modulated the PI3K/AKT pathway to control breast cancer pathogenesis.Conclusion: We provide the first evidence of the involvement of IRF6 in breast cancer pathogenesis, which was found to modulate the PI3K/AKT pathway via mediating PIK3R2; indicating that IRF6 can be targeted as a potential therapeutic treatment of breast cancer.Keywords: breast cancer, IRF6, proliferation, RNA sequencing, PIK3R2, PI3K/AKT

With the ability to penetrate to the most nonpolarized materials, terahertz (THz) imaging technologies show great potentials when it comes to nondestructive testing and biomedical sensing. But the resolutions of conventional THz imaging systems are constrained by the diffraction limit. To overcome this, evanescent harmonics decaying in space must be enhanced or transformed into propagating harmonics for far-field super-resolution imaging. Here, we demonstrate that the far-field super-resolution imaging in a broad THz frequency range can be realized by an ultrathin fan-shaped metallic grating. The rigorous mode-expansion theory is used to analyze the transmission of both propagating and evanescent harmonics inside the grating. We also find that a flat subwavelength metallic grating working in canalization regime has similar performance as a negative-index superlens. Both the near-field and far-field superlenses are experimentally verified by scaled models.

Inspired by the capability of structured illumination microscopy (SIM) in subwavelength imaging, many researchers devoted themselves to investigating this methodology. However, due to the free-propagating feature of the traditional structured illumination fields, the resolution can be only improved up to two-fold of the diffraction-limited microscopy. Besides, most of the previous studies, relying on incoherent illumination sources, are restricted to fluorescent samples. In this work, a subwavelength non-fluorescent imaging method is proposed based on the illumination of terahertz traveling waves and plasmonics. Excited along with a metal grating, the spoof surface plasmons (SSPs) are employed as one of the illuminating sources. When the scattering waves with the SSPs illumination are captured, the sample’s high-order spatial frequencies (SF) components are already encoded into the obtainable low-order ones. Then, a modified post-processing algorithm is exploited to shift the modulated SF components to their actual positions in the SF domain. In this manner, the fine information of samples is introduced to reconstruct the desired imaging, leading to an enhancement of the resolution up to 0.12λ0. Encouragingly, the resolution can be further enhanced by attaching extra illumination of SSPs with an elaborately selected frequency. This method holds promise for some important applications in terahertz non-fluorescent microscopy and sample detection with weak scattering.

Background: The extracellular matrix (ECM) component serglycin promotes the epithelial-to-mesenchymal transition (EMT) and metastasis in an autocrine manner. However, the detailed mechanism underlying the roles of serglycin in Hepatocellular carcinoma (HCC) metastasis progression remains to be clarified.Methods: Analyzing 123 patients’ serum by ELISA to investigate the association between serglycin expression and HCC metastasis and prognosis. Serglycin, CRISPLD2, and YAP were overexpressed or knocked down with vector or RNAi. The RNA - sequence was used to screen serglycin downstream effectors, followed by bioinformatics, ChIP-PCR, luciferase, and promoter site mutation to identify novel target genes. The metastatic abilities of serglycin were demonstrated by a series of in vitro and in vivo experiments. Immunofluorescence, flow cytometry, and western blotting were carried out to demonstrate the potential mechanisms of serglycin.Results: We observed that serglycin was overexpressed in HCC tissues and serum, and its level was associated with metastasis and poor prognosis. By gain- and loss-of-function approaches, we found serglycin affects migratory motility and metastatic capacity in vitro and in vivo, and it's significantly associated with the stemness-like properties. Interestingly, serglycin activated the effector YAP of Hippo pathway, and further study verified the crucial role of serglycin/YAP in tumorigenesis by the DEN-induced HCC mouse model. Furthermore, the CRISPLD2 was selectively upregulated by serglycin, the axis of serglycin / YAP / CRISPLD2 regulated metastatic capacity in HCC cells, it revealed CRISPLD2 was the direct target gene of serglycin-mediated YAP/TEAD1 complex. Besides, serglycin-mediated YAP pathway enhanced cell sorafenib resistance, sorafenib combined with verteporfin reversed serglycin-mediated cellular insensitivity to sorafenib therapy.Conclusions: Autocrine ECM serglycin plays a crucial role in the process of stemness maintenance, tumorigenesis, and metastasis via selective reactivation of the novel YAP/CRISPLD2 developmental axis promotes metastasis and sorafenib resistance in Hepatocellular carcinoma, YAP-TEAD1 inhibitor verteporfin reversed serglycin-mediated cellular sorafenib resistance.

A design of real-time tunable-focus reconfigurable active metasurfaces is proposed in this paper. With the element space of 16 mm (0.458λ), a 1-bit real-time reconfigurable active metasurface element is successfully designed to work at 8.595 GHz. From 7.71 GHz to 9.43 GHz, the element realized a 1-bit phase shift with a relative bandwidth of 20% within 180o ± 30o. Moreover, a negligible cross polarization is obtained and the amplitude loss is less than 0.8 dB for two states. Furthermore, the reflective metasurface is designed with an aperture size of 512mm×512mm (32×32) and aperture efficiency of 43.7% for the tunable beam focusing. By effectively designing the states of each element on the metasurface array, a single-beam focusing on θ = 0° and dual-beam focusing on θ = ±15° are achieved, respectively. Finally, the full wave simulation is performed to demonstrate to the functionalities and effects of the proposed metasurfaces, whose results are in good agreement with the theoretical design.

Manipulation of spoof surface plasmons (SSPs) has recently intrigued enormous interest due to the capability of guiding waves with subwavelength footsteps. However, most of the previous studies, manifested for a single functionality, are not suitable for multifunctional integrated devices. Herein, a bifunctional Luneburg-fisheye lens is proposed based on a two-dimension metal pillar array. Firstly, by tuning the geometric dimension of the metal pillars in the array, its ability to precisely manipulate the excited SSPs along one direction is confirmed, achieving subwavelength focusing and imaging with the resolution up to 0.14 times the wavelength. Then, separately controlling the propagation of the SSPs along the orthotropic directions is further implemented, and the bifunctional Luneburg-fisheye lens is realized. The bifunctional lens is characterized as a Luneburg one along the x-axis, whereas in the y-axis, it presents the properties of a Maxwell fisheye lens. The experimental results almost immaculately match with the simulation ones. This bifunctional lens can validly reduce the system complexity and exert flexibility in multifunctional applications, while the proposed metal pillar-based design method broadens the application range of gradient refractive-index lens in the microwaves, terahertz, and even optical ranges., 9 pages, 5 figures

Recent advances in hyperbolic metamaterials have spurred many breakthroughs in the field of manipulating light propagation. However, the unusual electromagnetic properties also put extremely high demands on its compositional materials. Limited by the finite relative permittivity of the natural materials, the effective permittivity of the constructed hyperbolic metamaterials is also confined to a narrow range. Here, based on the proposed concept of structure-induced spoof surface plasmon, we prove that arbitrary materials can be selected to construct the hyperbolic metamaterials with independent relative effective permittivity components. Besides, the theoretical achievable ranges of the relative effective permittivity components are unlimited. As proofs of the method, three novel hyperbolic metamaterials are designed with their functionalities validated numerically and experimentally by specified directional propagation. To further illustrate the superiority of the method, an all-metal low-loss hyperbolic metamaterial filled with air is proposed and demonstrated. The proposed methodology effectively reduces the design requirement for hyperbolic metamaterials and provides new ideas for the scenarios where large permittivity coverage is needed such as microwave and terahertz focus, super-resolution imaging, electromagnetic cloaking, and so on.

In order to exploit orbital angular momentum (OAM) transmitting data, multiple-mode OAM waves should be generated preferably by a fixed antenna. In this paper, a programmable 1-bit digital coding metasurface is presented for the generation of multi-mode converged OAM waves. The proposed reconfigurable element consists of a microstrip patch, a PIN diode, and a DC biasing circuit. Through electronically controlled the PIN diode ON and OFF, two states with a phase difference of 180°, i.e., "0" and "1" states, can be realized. By properly designing varying states of each element on the metasurface array, the OAM waves can be generated and dynamically reconfigured among l = 0 and l = 1 modes at 7.77GHz. As a consequence, it is potential in wireless communication applications.

Gyrotrons have been developed as terahertz wave sources in dynamic nuclear polarisation (DNP) system to increase the sensitivity of nuclear magnetic resonance (NMR) in the high-magnetic field regime. However, the transmission of the Gaussian beam from the gyrotron output window to the NMR system proves to be a critical challenge. In this study, a terahertz transmission system, composed of a rectangular corrugated waveguide and a back-to-back rectangular corrugated horn for Gaussian mode filtering, is proposed. The attenuation in the optimised 0.33 THz corrugated waveguide remains lower than 0.01 dB/m in a broad frequency range from 280 GHz to 450 GHz. Besides, the coupling coefficient from the electric field in the 0.33 THz mode-filtering horn to the fundamental HE11 mode in the rectangular corrugated waveguide is obtained nearly 99.5%. This terahertz transmission system is potential to be applied in DNP-NMR spectrometer based on continuous wave gyrotrons.

Terahertz waves generated by vacuum electron devices have been successfully applied in dynamic nuclear polarization enhanced nuclear magnetic resonance (DNP-NMR) technology to significantly enhance the sensitivity of high-field NMR. To reduce the magnetic field interference, the high-power terahertz wave source and the NMR spectrometer need to be separated by a few meters apart. Corrugated horns and directional couplers are key components for shaping high linearly polarized terahertz Gaussian beam and accurately coupling electromagnetic power in the transmission system. In this paper, a corrugated TE11-HE11 mode converter and a three-port directional coupler realized by its inner cylindrical wire array are proposed for a 330 GHz/500 MHz DNP-NMR system. The output mode of the mode converter presents a characteristic of highly linear polarization, which is 98.8% at 330 GHz for subsequent low loss transmission. The designed three-port directional coupler can produce approximately −33 dB electromagnetic wave power on port 3 in the frequency range between 300–360 GHz stably, which can be used to measure the electromagnetic wave power of the transmission line in real-time. The designed mode converter and direction coupler can be installed and replaced easily in the corrugated waveguide transmission system.

Perception is the interaction interface between an intelligent system and the real world. Without sophisticated and flexible perceptual capabilities, it is impossible to create advanced artificial intelligence (AI) systems. For the next-generation AI, called ‘AI 2.0’, one of the most significant features will be that AI is empowered with intelligent perceptual capabilities, which can simulate human brain’s mechanisms and are likely to surpass human brain in terms of performance. In this paper, we briefly review the state-of-the-art advances across different areas of perception, including visual perception, auditory perception, speech perception, and perceptual information processing and learning engines. On this basis, we envision several RD (2) auditory perception and computation in an actual auditory setting; (3) speech perception and computation in a natural interaction setting; (4) autonomous learning of perceptual information; (5) large-scale perceptual information processing and learning platforms; and (6) urban omnidirectional intelligent perception and reasoning engines. We believe these research directions should be highlighted in the future plans for AI 2.0.

In this work, an alternative method is proposed to realize terahertz far-field super-resolution imaging. Due the unique dispersive properties of the spoof surface plasmon (SSP), the spatial spectrum of the targets can be extracted and conserved by the adjacent SSP structure through a frequency canning operation. With the assist of a broadband coupler, the sampled information can be sent and retrieved in the far-filed. Then, the image with subwavelength resolution is constructed by inverse Fourier Transform. Although the resolution of $0.1\lambda$ is verified, the resolution can be further enhanced by optimizing the SSP structure. This work may find applications in non-destructive testing and biomedical imaging.

Based on the combination of propagation phase with geometric phase, to the best of our knowledge, a new reflective metasurface which can control the direction of reflected waves and excite spoof surface plasmon polariton (SSPP) simultaneously is proposed and numerically demonstrated for the circular polarization incident waves. The incident waves can be converted into SSP with longitudinal wave vector $k_{x}$ = $1.2 k_{0}$ or anomalously reflected with reflection angle $\theta _{r}$ = 13.9° under the illumination of the left or the right circular polarization beam, respectively. The respective converting efficiency of the left and right circular polarization can reach up to 70% and 82% at the frequency of 0.3 THz. Our study may open up new routes for polarization-related antennas, detectors and other practical terahertz devices.

In this Letter, we propose and experimentally demonstrate a simple but efficient method to excite spoof surface plasmons (SSP) through periodic metallic cylinders at microwave frequencies. The rigorous multiple scattering theory indicates that most of the incident propagating waves can pass the cylinders and be converted into the desired harmonics. Furthermore, by tuning the incident angle, controlling the directions of the excited SSP at different frequencies is also realized. The numerical simulations achieve a bidirectional efficiency of 90% at 9.68 GHz and unidirectional efficiency of 79%–85% at 7.46–9.7 GHz, when the incident angle changes from 60° to 120°. Meanwhile, the maximum contrast ratio between the powers of SSP launched in two opposite directions can reach up to 34 dB. The experimental results under 90° and 77.5° illuminations at 9.68 and 8.56 GHz provide strong support for the coupling mechanism. This method may provide technique support in the SSP-based communication and imaging systems.

A novel electronically reconfigurable reflectarray (RRA) element, based on slotting technique, is presented for an improved bandwidth performance. Composed by two substrate layers and one PIN diode, this element can be electronically controlled to generate two states with 180° phase difference, which is practical for large-aperture beam-scanning applications. As a result, a 1-bit phase shift is achieved within $180^{\circ}\pm 24^{\circ}$ from 7.66 to 8.52 GHz, which indicates a wide relative bandwidth of 10.96%. Moreover, the element loss is smaller than 1 dB for two states. A DC bias circuit is designed without influence on the reflection performance of the element.