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The increasing use of hyaluronic acid (HA) implants has made adverse effects more apparent. Here, we present a rare case of massive allergic dermatitis due to HA injections. We performed dermoscopy and color ultrasound, which clarified that this was an allergic dermatitis caused by fillers, and analyzed the possible causes of the allergy. Common treatments were compared, and the advantages of 5-FU-based treatment regimens and their associated mechanisms were noted. A low dose of 5-fluorouracil and triamcinolone acetonide was administered to the patient's entire face and neck, and significant efficacy was achieved. We aimed to gather evidence on extensive dermatitis caused by HA injection, provide new perspectives and solutions for subsequent HA injections, and promote further research on the potential mechanisms of extensive skin inflammation and allergies caused by local HA injections. [ABSTRACT FROM AUTHOR]

Non-binary low-density parity-check (NB-LDPC) codes can exhibit more considerable coding gain than their binary counterparts in numerous cases. To further exploit the benefit of NB-LDPC codes, in this letter, a novel type of non-binary LDPC codes, alterable subset non-binary LDPC (AS-NB-LDPC) codes, is proposed for reducing the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) systems. Firstly, we design the alteration scheme of AS-NB-LDPC codes to make $q$ -ary LDPC codes generate $q$ valid codewords through one alterable subset, and the codeword with the minimum PAPR is selected for transmission. Then inspired by the invertible subset for binary LDPC codes, the necessary and sufficient conditions for alterable subset generation are derived. Furthermore, we propose an improved progressive edge growth (PEG) construction method to obtain AS-NB-LDPC codes with favorable frame error rate (FER) performance. Simulation results verify the effectiveness of the proposed NB-LDPC codes. [ABSTRACT FROM AUTHOR]

In the particle-in-cell simulation study of this paper, it is found that the high-power terahertz radiation at twice the plasma frequency can be generated by the interaction between a weakly relativistic, large-radius, focused electron beam and an overdense plasma. The terahertz radiation is emitted from a multi-filament structure in the electron beam, which is caused by the coupling of the longitudinal two-stream instability and the transverse filamentation instability. The analysis of the k space of the plasma waves indicates that the radiation can be explained by the mode coupling among a forward oblique mode, a backward oblique mode, and a second harmonic radiation mode. The influences of the beam Lorentz factor and plasma density on the radiation power, efficiency, and coherence are also investigated. The present results not only contribute to the development of novel megawatt-level narrowband terahertz radiation sources, but also propose a potential terahertz radiation mechanism for the fundamental research of the beam-plasma system. [ABSTRACT FROM AUTHOR]

It is found that the plasma waves driven by an electron beam rotating in a magnetized overdense plasma can be converted into terahertz electromagnetic radiation by new mechanisms. According to the particle-in-cell simulation results, the radiation modes include a dominant extraordinary (X) mode at twice the plasma frequency 2 f p and a subordinate X mode at f p . The 2 f p radiation can be generated by the coupling of a beam mode and a scattered upper-hybrid (UH) mode, or by the coupling of a beam mode and a right-handed X mode. Here, the beam mode can be a UH mode or a left-handed X mode driven by the beam under the Cherenkov condition, and the right-handed X mode can be induced by high-order electron cyclotron maser instability. The f p radiation is the right- or left-handed fundamental X mode escaping from the plasma boundary. This study also shows that the breakdown of beam modulation is responsible for the radiation attenuation. The scheme proposed in this paper can be applied in high-power THz radiation sources and diagnosis of magnetized plasmas. [ABSTRACT FROM AUTHOR]

In this paper, the mechanism by which current reflux forms from a plasma-focused electron beam is studied theoretically and numerically by considering nonlinear interactions between the beam and plasma. We demonstrate that a moving virtual cathode can be generated at the end of a plasma ion channel due to the influence of the boundary plasma electrons on the beam, and that this accounts for reflux formation. In addition, the reflux formation condition is derived and analyzed via the beam envelope and space-charge-limited current theories. The results indicate that the virtual cathode tends to form at defocusing positions of the beam. Particle-in-cell simulations are used to verify the theoretical results and to show that the beam divergence and energy spread increase during current reflux formation. [ABSTRACT FROM AUTHOR]

The formation condition of the virtual cathode (VC) formed by a self-focusing relativistic electron beam in plasma is studied theoretically and numerically. Together with the threshold function of the VC formation and the self-focusing condition, the parametric regions of forming the VC are found. Then the theoretical result is verified by the particle-in-cell (PIC) simulation, which further shows the phase-space characteristics of the VC formation. This study not only provides a theoretical basis for creating VC with a self-focusing relativistic electron beam in plasma but also helps in parameter selections for the related beam-plasma experiments and simulations. [ABSTRACT FROM AUTHOR]

In this paper, a novel scheme of generating terahertz radiation is proposed, which considers a relativistic electron beam being modulated by its self-excited plasma wakefield in a plasma-filled slow-wave structure (SWS). Both the dispersion relation and the particle-in-cell simulation show that the self-modulation of the beam can act as a mode-selection method to excite the high-harmonics of the SWS and generate terahertz electromagnetic radiation. The present work gives a new thought for researching high-power and tunable terahertz sources. [ABSTRACT FROM AUTHOR]

An experimental study on electromagnetic (EM) radiation in an electron beam‐ion channel system is reported, which indicates the same result predicted by our previous theory. The system is formed in an arc plasma jet with a plasma density of 1017m−3, and the electron beam is driven by a voltage pulse of 20 kV. The result shows that the system can excite EM radiation in the range of the plasma frequency. The scheme is also hopeful to be used for generating high‐frequency and wide‐band EM radiation up to terahertz by enhancing the plasma density. [ABSTRACT FROM AUTHOR]

Polycaprolactone-based fillers are commonly used in plastic surgery to improve facial aging. However, adverse vascular events following these injections have been reported. An arterial embolism is a rare but serious complication associated with injectable filler procedures. We report a case of arterial embolism in a 35-year-old woman who received a polycaprolactone-based dermal filler at the nasal base and was treated with a regimen containing 5-fluorouracil. We discuss the potential causes of the patient's condition and assess the superiority of our method over conventional approaches. Before treatment, ultrasound detected a decreased flow velocity in the patient's right medial canthus artery with distal hypoperfusion, which improved significantly posttreatment. Long-term follow-up revealed near-disappearance of facial scarring. Our treatment effectively addressed facial artery embolism without any reported adverse reactions., Competing Interests: The authors have no financial interest to declare in relation to the content of this article., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)