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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.

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.

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.

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.

Spoof surface plasmon (SSP) meta-couplers that efficiently integrate other diversified functionalities into a single ultrathin device are highly desirable in the modern microwave and terahertz fields. However, the diversified functionalities, to the best of our knowledge, have not been applied to circular polarization meta-couplers because of the spin coupling between the orthogonal incident waves. In this paper, we propose and numerically demonstrate a terahertz spin-decoupled bifunctional meta-coupler for SSP excitation and beam steering. The designed meta-coupler is composed of a coupling metasurface and a propagating metasurface. The former aims at realizing anomalous reflection or converting the incident waves into SSP under the illumination of the left or right circular polarization waves, respectively, and the latter are used to guide out the excited SSP. The respective converting efficiency can reach 82% and 70% at 0.3THz for the right and left circular polarization incident waves. Besides, by appropriately adjusting the reflection phase distribution, many other diversified functionalities can also be integrated into the meta-coupler. Our study may open up new routes for polarization-related SSP couplers, detectors, and other practical terahertz devices.

In this paper, a linear polarization-controlled (LPC) spoof surface plasmon polaritons (SSPPs) meta-coupler with high efficiency and directionality is proposed and demonstrated in the terahertz (THz) regime. By changing the polarization (TE or TM polarization) of the incident electromagnetic (EM) waves, the corresponding SSPPs can be directionally excited towards opposite directions. The meta-coupler is composed of a coupling metasurface (CM) and two propagating metasurfaces (PMs) on both sides of CM. Under the illumination of specified polarization Gaussian beam, the unit cells of the CMs have the similar electric field distribution with that of PMs, which can realize a smooth and efficient transition between the surface waves and SSPPs. The respective excitation efficiency of the TE and TM polarization can reach up to 87% and 90% at the frequency of 0.355 THz. Besides, the PMs are designed to support the propagation of the specified TE or TM mode SSPPs. This guarantees a relatively high directionality (> 24 dB) in the frequency range of 0.325-0.375 THz. Our study may open up new routes for polarization-related antennas, detectors and other practical THz devices.

An efficiency way to enhance the excitation efficiency of spoof surface plasmons (SSP) is proposed and demonstrated in this work. Under the rigorous theoretical deduction, it is found that almost perfect transmission through transmissive metallic grating can be realized when the Fabry–Perot (FP) resonance occurs. A significantly high conversion efficiency 92% between incident waves and surface waves is achieved by transmissive metallic gratings under the situation of FP resonances. Further studies show that tuning the direction of excited SSP and compressing the thickness of coupler are also realized by tilting the incident waves and filling high-index dielectric, respectively. This work may provide technical supports for plasmonic applications.

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.

Terahertz imaging has recently attracted great attention owing to the abilities of high penetration and low ionizing damages. However, the low resolution and low contrast resulting from the diffraction limit and unwanted background illumination significantly hinder the extensive usage. In this Letter, we propose and numerically demonstrate a terahertz subwavelength imaging method capable of extracting only the edges and fine features of the targets. The underlying physics is the efficient transmission of the scattering evanescent waves related to key geometric information while blocking the propagating components. By exploiting the structurally induced plasmons in a bounded metallic waveguide, the transmission channel for evanescent waves is realized by hyperbolic metamaterials through periodically stacking dielectric layers. On this basis, high-contrast edge detection with a resolution up to 0.1 λ is demonstrated at terahertz wavelengths. The proposed terahertz imaging method may find important applications in non-destructive testing, weak scattering object detection, and high-contrast microscopy.

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.

Terahertz wireless communication has emerged as a fast-growing research area. Routing, which is designed to control the propagation of terahertz wave, is of great importance for building the terahertz all-optical communication network. Metamaterials provide a good method for manipulating the terahertz wave, which can be used to realize the wave router. To steer the input wave in different directions, for example negative refraction angle, some structures have been proposed, such as stacked structures and nanowire arrays. However, in these metamaterials, the incident wave is generally limited to transverse magnetic polarization. Here, a new terahertz routing method for transverse electric wave is put forward with using graphene magnetic metamaterials. Theoretical analysis is performed to show that this metamaterial has negative components not only in effective permittivity tensor but also in effective permeability tensor. Routing is realized by topological transitions between different dispersion regimes in this metamaterial. Our finding provides a new candidate for signal routing of terahertz wave.

Imaging below the diffraction limit is always a public interest because of the restricted resolution of conventional imaging systems. To beat the limit, evanescent harmonics decaying in space must participate in the imaging process. Here, we introduce the method of spatial spectrum sampling, a novel far-field superresolution imaging method for microwave and terahertz regime. Strong dispersion and momentum conservation allow the spoof surface plasmon polaritons (SSP) structure to become a sensitive probe for spatial harmonics. This enables that the spatial information of the targets including both propagating and evanescent components, can be extracted by tuning and recording SSP in the far field. Then, the subwavelength resolution is constructed by the inversed Fourier transform of the sampled spatial spectrum. Using the modified subwavelength metallic grating as the spoof plasmonic structure, a far-field resolution of 0.17 wavelength is numerically and experimentally verified, and two-dimensional imaging ability is also fully discussed. The imaging ability and flexibility can be further optimizing the SSP structures. We are confident that our working mechanism will have great potentials in the superresolution imaging applications in the microwave and terahertz frequency range, Comment: 7 figures,48 reference,24 pages

Based on phased-gradient metasurfaces, an efficient method is developed to convert waveguide modes in a parallel-plate waveguide. An effective wavevector is imparted to the incident mode at each interaction with matesurfaces, resulting in the mode conversion. The numerical simulation indicates that the efficiency and purity of TE1-to- TE2 conversion can significantly reach up to 99.98% and 99.99% at 9GHz. The conversion between TM3 and TM4 is also achieved, which gives a fair verification of the polarization insensitivity. This work can provide technical guidance for compact modes control.

A plasmonic band-stop reflective filter based on periodic graphene patch is proposed and numerically investigated using the FDTD method. The proposed filter has a simple three-layer structure, which is composed of graphene, dielectric layer, and metal. Simulated results exhibit that significant absorption peak can be achieved. The absorption spectra can be freely tuned in a broad frequency range by changing the chemical potential. Compared with traditional active filters, this filter does not require mechanical motion, which is suitable for many high-performance situations where stability is a primary concern. Besides, the structure of the filter is ultrathin and reduces the requirements of size and weight. The filter is valid for both transverse electric and transverse magnetic polarization. The filter can be used as a high-sensitivity sensor.

An ultra-broadband subwavelength resolution probe that consists of a Teflon rod and six metallic strips is developed for the near-field imaging system. The slit between two metallic strips maintains quasi-TEM modes, avoiding the problem of low coupling efficiency caused by the cutoff effect. The numerical calculations visualize the process of energy compression into a 0.047λ diameter spot with great field enhancement at the taper apex, and the probe holds subwavelength focusing behavior from 10 GHz to 0.25 THz. Although limited by the fabrication, the resolution of 0.16 and 0.25λ are still experimentally demonstrated at 14 GHz and 0.1 THz. The properties of easy fabrication and no cutoff frequency would lower the threshold of a high-resolution near-field imaging system.

The controversy of (p53) in nasopharyngeal carcinoma persists, despite the fact that many studies have been conducted on its correlation with latent membrane protein 1 (LMP1), bcl-2, and prognosis. To better understand this postulated relationship, a meta-analysis was performed based on existing relevant studies. A total of 19 individual studies with a total of 1189 patients were included in the meta-analysis. Overall, the results revealed a significant association of p53-positive status with a poor 5-year survival of nasopharyngeal carcinoma (NPC) patients as the risk difference (RD) was -0.17 (95% CI, -0.31, -0.03; P=0.02, Pheterogeneity =0.01).The overall odds ratio (OR) for LMP1 in the p53 positive group vs. negative group revealed that a significantly elevated risk of positive LMP1 in the former was achieved (OR 5.52 95% CI, 2.66-11.46; P0.00001, Pheterogeneity =0.78). Similarly, a strong correlation between bcl-2 and p53 was found with an OR 6.85 (95% CI, 2.37-19.74; P=0.0004, Pheterogeneity =0.48). However, there did not appear to be any correlations with clinical parameters such as gender, tumor site, lymph node metastasis,pathological type and TNM stage. In conclusion, p53 expression is related to the survival of nasopharyngeal carcinoma. It can be considered as the auxiliary detection index in treatment and prognosis of nasopharyngeal carcinoma.

A gradient index (GRIN) lens is proposed and demonstrated for efficiently focusing incident waves in terahertz regime. This lens is composed of three layers of metamaterial based on annular slots, allowing a large variation of the effective refractive index in both two bands. Thus we manage to design a dual-band focusing lens which can focus the terahertz radiation to a spot size smaller than the wavelength.

The high-order operating modes in gyrotrons are always converted into Gaussian beam for transmission. However, the Gaussian beam radiated from the gyrotrons is frequently non-ideal, which may result in poor coupling to the fundamental HE 11 mode in corrugated waveguides and high attenuation in the transmission line. Therefore, a back-to-back corrugated horn structure is designed in this paper for Gaussian mode filtering This structure is capable of enhancing the coupling coefficient from 82% to nearly 98%. Besides, the high coupling coefficient maintains during a broadband frequency range of $\mathbf{200 GHz }\leq J \leq 240$ GHz.

We theoretical and simulated demonstrate frequency scanning can be an effective approach to realize terahertz far-field subwavelength imaging. The imaging device composed of metallic gratings and coupler has the ability of coupling evanescent wave and transforming them to corresponding propagating waves so that the subwavelength details will be conserved in the imaging process. By carrying out frequency scanning simulation and a simple data processing from 0.1 THz to 0.24 THz, the operating spatial spectrum is dramatically extended to 5k0 (k is the wavenumber of 0.24 THz) in the far-field, which is well verified our method. Better spatial spectrum range can be expected by decreasing period of grating and increasing scanning frequency points. We are confident this method will find useful applications in terahertz imaging area.

A terahertz polarization converter composed of graphene patch is demonstrated. It can convert circularly polarized wave to linearly polarized wave from 4.6THz to 5.6THz with a transmission intensity more than 40%. The effect of the geometry on the transmitted circularly polarized waves is investigated. This periodic structure is then used in double layer structure to realize a polarization converter with twice the bandwidth compared with the single layer design. This offers a further step in developing ultrathin terahertz polarization components.

Based on the mode expansion theory, a detailed derivation of light transmission properties through fanshaped metallic grating (FMG) is presented. We confirm that all harmonics have considerable transmission coefficients through FMG under limited theoretical assumptions. This means FMG have ability to transmit an image with subwavelength resolution from inner face to outer face. Subsequent simulated results indicate a far-field surperlens by FMG with a resolution better than λ/10 can be obtained. The simulated results are in good agreement with the results of theoretical derivation. Lastly, we demonstrate that clearer image can be reconstructed on the condition of Fabry-Perot resonance, where both the propagating and evanescent waves almost hold same transmission coefficients. This theory can be applied in designing far-field imaging, highly sensitive detector in biosensing, and research in light-matter interactions.

The tunable plasmon-induced transparency (PIT) metamaterial structures composed of periodically patterned graphene microholes and microribbons are presented and numerically investigated. The interaction between plasmonic modes that lead to the PIT effect is studied in detail by analyzing the field distributions. A coupled Lorentz oscillator model is used to explain the mechanism of the PIT effect. The transparency window of PIT structures can be dynamically tuned by varying the Fermi level of the graphene. The tunable graphene PIT device may have potential applications in designing optical switching devices, ultra-compact sensors and slow light devices in the THz region.

Nasopharyngeal carcinoma (NPC), which originates from the nasopharynx, is highly prevalent in Southern China and Southeast Asia, and more than 90% of all NPCs are non-keratinizing undifferentiated cells or poorly differentiated squamous cells. Cancer stem cells (CSCs) are capable of self-renewal and have differentiation potential. These properties form the basis of cancer initiation, development, and radiochemoresistance. However, the molecular mechanisms underlying NPC CSC maintenance remain poorly understood. Here, genomic expression profiling using our previously established monoclonal cellular and animal models revealed that interferon regulatory factor 6 (IRF6) was downregulated in highly metastatic NPC cells, cancer stem-like NPC cells and animal models. Functional assays revealed that elevated IRF6 expression suppressed cell proliferation, growth, CSCs properties and enhanced cell chemotherapeutic sensitivity. However, silencing IRF6 resulted in opposing effects. Moreover, we determined that as a tumor suppressor gene and transcription factor, IRF6 directly bound the upstream region of the ATP-binding cassette sub-family G member 2 (ABCG2) DNA element and suppressed target ABCG2 expression in NPC cells. Consistently, an inverse correlation was observed between the mRNA levels of IRF6 and ABCG2 in clinical NPC samples. With these results, we provide the first evidence that IRF6 directly targets the ABCG2 gene and selectively kills CSCs in NPC and that IRF6 may be a valuable tool for developing new CSC-targeted treatment strategies for undifferentiated NPC patients.

The resolution of conventional terahertz (THz) imaging techniques is limited to about half wavelength, which is not fine enough for applications of biomedical sensing and nondestructive testing. To improve the resolution, a new superlens, constructed by a monolayer graphene sheet combining with a grating voltage gate, are proposed in this paper to achieve deep super-resolution imaging in the THz frequency range. The main idea is based on the Fabry-Perot resonance of graphene edge plasmon waves. By shaping the voltage gate into a radial pattern, magnified images of subwavelength targets can be obtained. With this approach, the finest resolution can achieve up to λ/150. Besides, the superlens can be conveniently tuned to work in a large frequency band ranging from 4.3 THz to 9 THz. The proposal could find potential applications in THz near-field imaging systems.

A beam-scanning terahertz (THz) radiation mechanism in a free-electron-driven grating system is proposed for THz applications. By loading a period-asynchronous rod array above the grating, the spoof surface plasmon (SSP) originally excited by the electron changes its radiation characteristics owing to the rod-induced Brillouin zone folding effect. The rod array functions as an antenna and converts the SSP into a spatial coherent THz radiation. The radiation frequency and direction can be precisely controlled by the electron energy. The field intensity of the radiation is increased approximately 20 times compared with that of the conventional Smith-Purcell radiation in the same frequency range. In addition, a microwave-band scaling prototype is fabricated and the frequency-controlled radiation is measured. Excellent agreement between the experimental and simulated results is obtained. This study paves the way for the development of on-chip THz sources for advanced communication and detection applications.

Emerging evidence confirms that cancer stem cells (CSCs) are responsible for the chemoradioresistance of malignancies. EBV-encoded latent membrane protein 1 (LMP1) is associated with tumor relapse and poor prognosis of nasopharyngeal carcinoma (NPC). However, whether LMP1 induces the development of CSCs and the mechanism by which this rare cell subpopulation leads to radioresistance in NPC remain unclear. In the present study, LMP1-transformed NPC cells showed significant radioresistance compared to the empty vector control. We found that LMP1 up-regulated the expression of several stemness-related genes, increased the cell number of side population (SP) by flow cytometry analysis, enhanced the self-renewal properties of the cells in a spherical culture and enhanced the in vivo tumor initiation ability. We also found that LMP1 positively regulated the expression of the CSC marker CD44. The CD44(+/High) subpopulation of the LMP1-transformed NPC cells displayed more significant CSC characteristics than the CD44(-/Low) subpopulation of the LMP1-transformed NPC cells; these characteristics included the upregulation of stemness-related genes, in vitro self-renewal and in vivo tumor initiation ability. Importantly, the CD44(+/High) subpopulation displayed more radioresistance than the CD44(-/Low) subpopulation. Our results also demonstrated that phosphorylation of the DNA damage response (DDR) proteins, ATM, Chk1, Chk2 and p53, was inactivated in the LMP1-induced CD44(+/High) cells in response to DNA damage, and this was accompanied by a downregulation of the p53-targeted proapoptotic genes, which suggested that the inactivation of the p53-mediated apoptosis pathway was responsible for the radioresistance in the CD44(+/High) cells. Taken together, we found that LMP1 induced an increase in CSC-like CD44(+/High) cells, and we determined the molecular mechanism underlying the radioresistance of the LMP1-activated CSCs, highlighting the need of CSC-targeted radiotherapy in EBV-positive NPC.

A new scenario to realize superfocusing of terahertz waves based on a gradient index (GRIN) metasurface is proposed. To design the GRIN material, a robust algorithm is presented and numerically demonstrated to retrieve the constitutive effective parameters (permittivity and permeability) of the metasurface from the measurement of S parameters. In addition, a new kind of unit cell with a simple structure is designed to verify the theory of effective parameters. By computing the effective refractive index of the unit cell using the algorithm, we design a plate with a thickness of approximately 0.11λ0 (free-space wavelength) at 0.967 THz to superfocus terahertz waves in one dimension. We also revise the theory of superfocusing to make full use of the coupling effect among the cells in the plate and are able to demonstrate it. Comprehensive simulations of focusing are provided, and the full width at half-maximum beam width reaches up to 0.167λ0 at a distance of 0.2λ0. The focusing depth can be further enhanced by decreasing the cell size of the metasurface. This work is beneficial for metasurface design, super-resolution imaging, and other applications in the near field.

In this paper, we propose and numerically demonstrate a new way to realize superfocusing of terahertz waves via the spoof surface plasmons (SSP). With the assist of a modified subwavelength metallic grating, a near-field rapid oscillation can be formed, originating from the Fabry-Perot resonances due to the reflection of SSP waves at terminations. We show that the field pattern of oscillation on textured metallic surface can be engineered by adjusting groove width and grating number. This produces a desired modulation of phase and amplitude for the radiationless electromagnetic interference (REI) focusing. The effective focusing depth through the corrugated metal is evaluated by the full-width-half-maximum (FWHM) beamwidth. At the situation of third-order Fabry-Perot resonance, the FWMH reaches up to 0.069λ at a distance of 0.1λ, improving the beamwidth by more than 540% compared with a single slit. The FWHM is optimized to 0.06λ as the order of Fabry-Perot resonance becomes seven, leading to the superfocusing metric of 1.67. On the basis of this, we further show the focusing ability can be held on the ultra-thin metallic grating. Two-dimensional subwavelength focusing behavior is also numerically verified. Our study may extend the working distance of sensing and super-resolution imaging devices at terahertz frequency.