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Objective To investigate the effects of down-regulation of long non-coding RNA-H19 (lncRNA-H19) expression on apoptosis and autophagy of human keloid fibroblast cell line and to explore potential mechanism. Methods Human scar fibroblasts cell line (KFs) and normal human dermal fibroblasts cell line (HDFs) were collected and KFs cells were infected with lncRNA-H19F low-expressing adenovirus (si-lncRNA-H19) and empty virus vector without si-lncRNA-H19 (si-eGFP). They were divided into HDFs group, KFs group, si-lncRNA-H19+KFs group and si-eGFP+KFs group. KFs cells were co-transfected with si-lncRNA, mTOR over-expressing adenovirus (Ad-mTOR) and empty vector (Ad-eGFP-m), then divided into KFs group, si-lncRNA-H19+Ad-mTOR group,si-eGFP+Ad-mTOR group, si-lncRNA-H19+Ad-eGFP group and si-eGFP+Ad-eGFP group. RT-qPCR was used to detect the expression of lncRNA-H19; flow cytometry was used to detect the cell apoptosis ; autophagy was examined by EM microscopy with fluorescence (acridine orange,AO) staining; immuno-histochemical method was used to detect the positive expression of autophagy pathway-mammalian target of rapamycin (mTOR); Western blot was used to detect the expression of apoptosis and autophagy-related proteins. Results Compared with the HDFs group, the expression of lncRNA-H19 and mTOR activity in the KFs group increased and the number of autophagic vesicles and the expression of apoptosis and autophagy-related proteins decreased (P＜0.05); after down-regulating lncRNA-H19 in KFs cells, the activity of mTOR in KFs cells decreased and apoptosis/autophagy increased (P＜0.05). Up-regulating mTOR while down-regulating lncRNA-H19 lead to more autophagy and apoptotic in KFs cells as compared to that resulted from down-regulation of lncRNA-H19 alone (P＜0.05). Conclusions Down-regulation of lncRNA-H19 expression may promote the autophagy and apoptosis of KFs cells through inhibiting activation of mTOR pathway.

Electromagnetic vortex carries the orbital angular momentum, one of the most fundamental properties of waves. The order of such vortex can be unbounded in principle, thus facilitating high-capability wave technologies for optical communications, photonic integrated circuits and others. However, it remains a key challenge to generate the high-order vortex beams in a reconfigurable, broadband and cost-effective manner. Here, inspired by the balanced-ternary concept, we demonstrate the reconfigurable generation of order-controllable vortices via cascaded N-layer metasurfaces. We theoretically showed that 3N−1${3}^{N}-1$ different vortex modes can be generated by cascading N metasurfaces, each one serving as an individual vortex beam generator for the order of 3k${3}^{k}$ (k = 0,1,2 …, N−1$N-1$). As a proof-of-concept demonstration, a reconfigurable generation of 26 different vortex beams, with orders from 1 to 13 and from −1 to −13, is showcased in a broad millimeter-wave region by a cascade of 3 metasurfaces. Our method can be easily extended to vortex beam generator of arbitrary orders in a reconfigurable and easily implementable manner, paving a new avenue towards tremendous practical applications.

Defects and microstructures have been utilized to effectively modulate electromagnetic (EM) wave absorption for mitigating electromagnetic pollution and stealth issues. However, precisely feasibly tailoring them still remains challenging. Here, by using a multilevel hollow cobalt sulfide embedded in a heteroatomic sulfur (S) ‐doped carbon aerogel, a preferential reaction strategy of modulating point defects and hollow microstructures via controllable S atoms migration is proposed to improve the EM wave absorption. S atoms contribute to the creation of hollow structures via Kirkendall effects, as well as inducing point defects in the carbon lattice through doping. More significantly, the mechanisms prioritizing the formation of hollow structures over defects have been discovered, with low‐velocity atomic migration primarily modulating the microstructure for interfacial polarization and impedance matching, and high‐velocity atom migration focused on introducing defects to achieve polarization and conductive loss. The resulting aerogel exhibits an exceptionally maximum reflection loss of −52.82 dB and an effective absorption bandwidth of 8.82 GHz, which far exceeds most of the currently reported materials. Experimental and theoretical approaches, including microwave heating, Tesla interaction, first principles, and far‐field simulation, are comprehensively employed to verify its absorption effect and mechanism. Furthermore, the combination of excellent infrared stealth and self‐cleaning properties opens up its potential applications in complex environments. [ABSTRACT FROM AUTHOR]

Thermal interface materials (TIMs) play a pivotal role in the transfer of heat from high‐temperature sources, such as CPUs, to heat sinks in power electronics. The effectiveness of grease‐type TIMs is determined by their effective thermal impedance (REFF), which hinges on optimizing both the specific bulk (RB) and contact (RC) thermal resistances. Achieving concurrent optimization of these resistances poses a significant challenge, especially in high filler loading TIMs, typically above 76 vol%. This research leverages interface engineering through Self‐Assembled Monolayers (SAMs) to address this challenge. A substantial decrease in REFF is realized to 0.169 K cm2 W−1, a tenfold enhancement compared to non‐SAM treated TIMs, which exhibit REFF values of 2.265 K cm2 W−1. This leap in performance is primarily ascribed to the reduced surface energy of SAM treated Al2O3, leading to lower particle‐to‐particle Van der Waals forces, thereby improving particle dispersion and strengthening interfacial bonds. Furthermore, longer carbon chains in SAMs result in increased RB, yet a decrease in RC, due to the chains' capacity for enhanced energy absorption and molecular entanglement. The investigation underscores the significance of shorter‐chain SAMs in fine‐tuning thermal resistance, highlighting the crucial role of molecular architecture in the design of advanced TIMs. [ABSTRACT FROM AUTHOR]

Recently, reconfigurable metasurfaces have facilitated dynamic manipulation of electromagnetic (EM) waves, opening new opportunities for fascinating meta-devices. So far, most devices are working in reflection region with limited polarization states. Here, we demonstrate a reconfigurable multifunctional transmissive metasurface for both linearly and circularly polarized waves manipulations. Specifically, the designed meta-atom contains dual-layer metallic cross-strips and one-layer circular slotted patch. Eight positive-intrinsic-negative diodes are loaded between each strip structure through via hole, with each two of diodes as a group along x- and y-direction, respectively, and thus supporting four switchable states via different applied bias voltages. Numerical results indicate that the designed meta-atom achieves high-rate transmission of 0.9 and individual phase manipulation in four independent transmission channels at 7.4 GHz. As a proof-of-concept demonstration, we numerically and experimentally show different versatile functionalities, including anomalous deflections with steered beams in range of 0° ∼ 40°, orbital angular momentum generation with mode of l = 1, and beam focusing among four polarization-encoded channels at 7.4 GHz. Our metasurface owns the advantages of multi-polarization EM wave manipulations in transmission mode, which completely distinguishes from previously reported works with single polarization in reflection mode.

Metamaterials have become a promising alternative for stealth technology due to their impressive abilities to freely manipulate electromagnetic waves. With the development of radar detection technology, stringent performances are required for metamaterial absorbers (MAs), such as wideband, wide‐angle operation, and thin thickness. Herein, a systematic strategy to achieve thin broadband MAs based on trilayer indium tin oxide (ITO) resistive films with multimodes is proposed. The operation mechanism and bandwidth enhancement are analyzed and discussed in terms of the equivalent circuit model and surface current distributions. Guided by the established impedance‐gradient theory, an absorber with high‐efficiency absorption is achieved. Numerical results show that it achieves operation bandwidth (reflection loss

ZrO2/Al2O3porous ceramics were prepared by gel-foaming technique. The rheological property of slurry, the effect of solid content on the microstructure and mechanical property of the porous green bodies and the relationship between the MgO sintering additive content with the compressive strength and porosity of porous ceramics were investigated. The results show when the dispersant content is 0.4%(mass fraction), ball milling time is 4 h and the pH value is 4, the low viscosity is conductive to gelcasting. The porosity of green body reduces with the increase of solid content. The excessive solid content makes the slurry hard to flow, and the big pores and cracks form during gelcasting process, then the compressive strength of green body decreases. The mechanical properties of porous ceramics are improved with the phase transformation and micro-crack toughening induced by the ZrO2. The densification of pore supports increases, the porosity reduces and compressive strength increases with the increase of sintering additive content. The highest compressive strength is 30 MPa. The porous ceramics with appropriate porosity and high compressive strength can be prepared by introducing suitable contents of ZrO2 and sintering additive.

Recently, some advanced computer algorithms, including the inverse design method based on deep learning, have been widely applied to design versatile electromagnetic devices, featuring fast design and high efficiency especially in the global optimization problem. However, enormous amount of data generated from blind preliminary and computationally expensive simulations to predict the optical responses is required. Herein, to overcome this shortcoming of traditional deep-learning-based inverse design method, a fast, highly efficient, and sufficiently accurate synergetic strategy for devising photonic applications is presented, which integrates an explicit equivalent-circuit-intervened model as the guide in the implicit deep learning method to avoid blind calculations. As a case study of the proposed synergetic paradigm, the absorbers with customized and challenging spectral patterns are explored. For verification, three proof-of-concept designs were characterized: single-layer notched-band absorption, dual-layer trap absorption, and triple-layer ultra-wideband absorption. Our approach solves the knotty issues of batch designs, as well as the complex and time-consuming processes, suffered in traditional approaches. Moreover, our demonstrated equivalent-circuit-intervened intelligent strategy can be directly extended to various other photonic architectures, advancing a significant step toward real-world applications.

Abstract Electromagnetic metasurface cloaks provide an alternative paradigm toward rendering arbitrarily shaped scatterers invisible. Most transformation-optics (TO) cloaks intrinsically need wavelength-scale volume/thickness, such that the incoming waves could have enough long paths to interact with structured meta-atoms in the cloak region and consequently restore the wavefront. Other challenges of TO cloaks include the polarization-dependent operation to avoid singular parameters of composite cloaking materials and limitations of canonical geometries, e.g., circular, elliptical, trapezoidal, and triangular shapes. Here, we report for the first time a conformal-skin metasurface carpet cloak, enabling to work under arbitrary states of polarization (SOP) at Poincaré sphere for the incident light and arbitrary conformal platform of the object to be cloaked. By exploiting the foundry three-dimensional (3D) printing techniques to fabricate judiciously designed meta-atoms on the external surface of a conformal object, the spatial distributions of intensity and polarization of its scattered lights can be reconstructed exactly the same as if the scattering wavefront were deflected from a flat ground at any SOP, concealing targets under polarization-scanning detections. Two conformal-skin carpet cloaks working for partial- and full-azimuth plane operation are respectively fabricated on trapezoid and pyramid platforms via 3D printing. Experimental results are in good agreement with numerical simulations and both demonstrate the polarization-insensitive cloaking within a desirable bandwidth. Our approach paves a deterministic and robust step forward to the realization of interfacial, free-form, and full-polarization cloaking for a realistic arbitrary-shape target in real-world applications.