Search Results (6,017)

This paper presents a corrugated Vivaldi antenna architecture targeting sub-6 GHz and millimeter-wave frequency bands for 5G CubeSat applications, combining experimental validation at sub-6 GHz with a simulation-based scaling study at 26.5 GHz. Existing CubeSat antenna designs either target a single frequency band or rely on complex metamaterial structures incompatible with nanosatellite fabrication constraints. To address this gap, a single-element corrugated Vivaldi antenna measuring 90 mm × 80 mm is designed, fabricated on FR-4 substrate, and experimentally validated at 3.5 GHz, confirming a wide impedance bandwidth of 2.75 GHz and a peak gain of 9.6 dBi. The strong agreement between CST Studio Suite simulations and measurements validates the electromagnetic solver configuration, which is subsequently applied, as a simulation-based design study, to a geometrically scaled version on Taconic RF-60A substrate operating at 26.5 GHz. The miniaturized single-element version achieves a simulated 17 GHz ultra-wideband response and 6 dBi gain in a 7.32 mm × 6.32 mm footprint. Two- and four-element array configurations at 26.5 GHz demonstrate systematic simulated gain progression to 9 dBi and 13 dBi, respectively, with beamwidth narrowing from 49${}^{\circ }$ to 30${}^{\circ }$. All 26.5 GHz designs are simulated with lossy copper metallization ($\sigma =5.8\times {10}^7$ S/m) and are entirely simulation-based; experimental mmWave validation is a designated target for future work. These results establish a validated design and scaling roadmap for corrugated Vivaldi antennas spanning sub-6 GHz and millimeter-wave bands, offering a cost-effective and CubeSat-compatible solution for high-data-rate inter-satellite communication links. Full article

Serratia marcescens is a nosocomial pathogen that has acquired resistance to multiple antibiotics, necessitating alternative antimicrobial strategies. The aim of this study was to isolate and characterize a novel phage (ØAS2) against Serratia marcescens and evaluate its biocontrol potential in dairy matrices. In this study, a lytic bacteriophage specific to S. marcescens, designated ØAS2, was isolated from sewage samples collected in Assiut, Egypt. Phage ØAS2 was characterized using plaque assays, transmission electron microscopy (TEM), host range determination, pH and thermal stability tests, and one-step growth curve analysis. Its ability to inhibit bacterial growth and disrupt biofilms was also evaluated in vitro. TEM revealed that ØAS2 possesses an icosahedral head approximately 47.2 nm in diameter and a very short tail, consistent with the morphology of a member of the class Caudoviricetes that exhibits podovirus-like morphology. The phage exhibited a broad host range, infecting various Serratia strains as well as other Gram-negative bacteria, including Klebsiella spp., Escherichia coli, Salmonella typhi, and Shigella spp. ØAS2 was thermostable up to 60 °C and showed maximum activity at pH 8. One-step growth curve analysis revealed a short latent period of 10 min and a burst size of 115 PFU per infected cell. ØAS2 effectively inhibited the growth of S. marcescens SM02 in vitro and significantly reduced preformed biofilms at different multiplicities of infection (MOIs). When applied to skim milk and fresh soft cheese at various MOIs (Multiplicities of Infection), the phage successfully controlled bacterial contamination under refrigerated storage (7 °C for 7–10 days). At MOI 5.0, phage ØAS2 reduced biofilm biomass by 25.6%, planktonic growth by 85.7%, and achieved a reduction of 2.1 log₁₀ CFU/mL in skim milk. These findings indicate that ØAS2 is a promising biocontrol candidate for managing S. marcescens spoilage in dairy products. Full article

Seismic metamaterials (SMs) have emerged as a novel wave-control strategy for earthquake-resistant engineering, offering the potential to manipulate seismic waves via artificially designed periodic/resonant structures. Field and laboratory experiments are critical to bridge theoretical predictions and engineering practice, yet a systematic synthesis focusing on experimental progress remains lacking. This review systematically classifies SMs into buried (BSMs), above-surface (ASMs), and partially embedded (PESMs) configurations, summarizing their structural designs, attenuation mechanisms, experimental performance, and key limitations. Results show that SMs can achieve >70% attenuation in the 0–50 Hz seismic band, with buried periodic barriers reaching 99.7% energy blocking and forest-like ASMs achieving 93–99% Rayleigh wave reduction. PESMs exhibit superior adaptability to shallow soils, with bandgaps concentrated in 1.5–14.5 Hz (building-sensitive range). Current experiments have advanced from single mechanisms to multi-mechanism synergy and from specialized materials to conventional concrete/steel. However, critical gaps remain: scaling-induced deviations, poor complex-geology adaptability, lack of long-term durability, and insufficient multi-waveform control. Finally, we propose a 3–10-year engineering roadmap and outline future directions: multi-waveform regulation, soil–metamaterial dynamic matching, durability design, and full-scale intelligent upgrades. This work aims to provide a critical experimental reference for the practical deployment of SMs. Full article

To address identity cloning, credential leakage, and delayed authorization in unmanned aerial vehicle (UAV) systems operating in open airspace, we propose a zero-trust authentication and authorization framework. SM9 identity-based mutual authentication establishes a traceable digital identity anchor. On-demand rotor acoustic verification then checks whether the current platform matches the registered identity. A Beta-distribution trust model converts authentication, verification, and behavioral evidence into dynamic authorization decisions. Experimental results show that the acoustic module blocks 104 of 110 spoofing samples. Under identity-cloning attacks, the attacker’s trust value decreases from about 0.97 to 0.27 and falls below the isolation threshold of 0.4. Compared with continuous acoustic authentication, on-demand triggering reduces authentication activation frequency, average inference latency, and normalized energy consumption by 86.8%, 83.6%, and 83.0%, respectively. These results indicate that the framework links identity confirmation, entity verification, and continuous authorization under resource-constrained UAV conditions. Full article

Sustainable EV charging infrastructure is fragmented by proprietary applications, vendor lock-in, and weakly time-differentiated pricing, blunting its contribution to urban-mobility decarbonisation. This paper asks whether an open-protocol, super-app-mediated photovoltaic–storage charging architecture can jointly resolve these three fragmentations under deployed field conditions and what its sustainability profile then looks like. We report a campus photovoltaic–storage microgrid integrating heterogeneous EV chargers under an open, vendor-neutral charging-control protocol with super-app authentication and payment replacing dedicated charging applications and a time-differentiated tariff aligned at the meter-interval level with the underlying utility wholesale rate; the deployment is exercised through a researcher-scheduled commissioning campaign of 13 sessions designed to establish functional correctness across the operating envelope rather than to measure user behaviour. Three results emerge across cross-vendor compatibility, onboarding friction, and grid alignment. First, basic message-level OCPP compatibility is sustained across two charger vendors under a single cloud management system—in sequential single-vendor sessions—including the full charging profile up to near-rated DC peak power. Second, the super-app-mediated workflow, which requires no charging-specific application installation and no new charger-operator account, structurally eliminates the dedicated application installation and the email/SMS/credit-card verification round-trips of conventional onboarding, compressing measured first-use end-to-end interaction to 31 s; relative to reconstructed commercial-operator baselines, this is, to the best of the authors’ knowledge, an order-of-magnitude reduction rather than a controlled benchmark. Third, mid-day energy delivery aligns incidentally with the utility off-peak window, not user-driven demand shifting, while PV-displacement and BESS-discharge contributions to charging are bracketed by scenario rather than being separately metered. The paper’s contribution is therefore a replicable, policy-embedded sustainable charging architecture validated at field scale within the New Taipei Net-Zero Carbon Demonstration Site Programme, with no claim of global novelty; the same architecture is structurally positioned to convert the observed incidental grid-friendliness into a deliberate, user-facing benefit via a hardware-free mid-day-discount redesign. Full article

The control of Dual-Star Induction Machines (DSIMs) with high performance remains a challenging task, particularly in the presence of parameter variations and under sensorless operation. In practice, widely used controllers such as Proportional–Integral (PI) and classical sliding mode (SM) often reach their limits, especially in terms of dynamic responses, sensitivity to disturbances, and chattering, which can negatively affect system stability and efficiency. In this work, an improved Rotor Flux-Oriented Control (RFOC) strategy is proposed. It combines a super-twisting sliding mode (STSM) speed controller with a Model Reference Adaptive System (MRAS) observer. The STSM controller ensures faster convergence and enhanced robustness while significantly reducing chattering. Meanwhile, the MRAS observer enables accurate rotor speed estimation without mechanical sensors, thereby simplifying the system and improving reliability. The control scheme is developed using the Xilinx System Generator (XSG) in a fixed-point environment, providing an FPGA-oriented and compatible simulation framework. To assess its effectiveness, the proposed method is evaluated through several simulation scenarios and compared with conventional RFOC-PI and RFOC-SM approaches. The results demonstrate clear improvements in dynamic performance, disturbance rejection capability, and steady-state accuracy. Overall, the proposed approach provides a practical and efficient solution for DSIM drive systems operating under demanding conditions. Full article

Rock-forming minerals, olivine and pyroxene, from three ore-bearing intrusions in the Norilsk districts were studied. They are the Norilsk 1 and the Northern and Southern Maslovsky massifs with PGE-Cu-Ni ores, located in the Norilsk syncline. Trace elements such as Al, Ti, Co, Cu, Nd, Sm, Ce, Cr, V, Dy, Y, Yb, Er, Sr, and Eu were determined by LA-ICP-MS. The authors found differences in mineral compositions between picritic gabbro-dolerites from these intrusions. The parental melt of the Southern Maslovsky intrusion corresponded to tholeiitic basalt containing (wt.%) H₂O—0.65, CO₂—0.16, and B—0.004. It was concluded that parental magmas for ore-bearing intrusions had no specific features and were closed to intraplate basalts. Full article

Student mental health, stress, and success are interconnected, yet the mechanisms linking them remain insufficiently understood. Drawing on Stress Optimization and Self-Regulated Learning (SRL) theories, this study examined how stress appraisals and learning practices jointly contribute to student mental health and academic functioning in post-secondary students, supporting a view of student success that comprises both feeling well psychosocially and functioning well academically. Using a sample of 226 university students, the study replicated prior work on the predictive roles of coping self-efficacy (CSE) and stress mindset (SM) across indicators of student success, including flourishing mental health, motivation-related challenges, social-emotional challenges, and GPA. It extended this work by testing whether metacognitive monitoring and adaptation, and academic social engagement, mediated these relationships. Results showed that neither CSE nor SM significantly predicted GPA, suggesting that stress appraisals alone may be insufficient to explain academic achievement. However, both CSE and SM significantly predicted flourishing mental health, and CSE was additionally associated with fewer motivation-related and social-emotional challenges. Mediation analyses indicated that metacognitive monitoring partially explained the relationship between CSE and reduced motivation challenges, while academic social engagement mediated relationships between stress appraisals and social-emotional challenges and mental health. Findings underscore the value of integrating psychosocial and educational perspectives in promoting student success. Full article

A novel material, chitosan oligosaccharide@melamine polyphosphate (CMP), with enhanced flame-retardant and hydrophobic properties, was synthesized by cross-linking melamine polyphosphate (MPP) with chitosan oligosaccharide. Compared with MPP, the CMP overcomes its inherent drawbacks when used as a flame retardant in polylactic acid (PLA) composites, namely the high loading demand and unsatisfactory interfacial compatibility with the polymer matrix. The results demonstrated that the peak heat release rate (p-HRR) dropped significantly in comparison to pure PLA, from 304.69 kW·m⁻² to 210.39 kW·m⁻², while the fire performance index (FPI) increased from 0.1 to 0.48 s·m⁻²·kW⁻¹. Furthermore, the fire growth index (FGI) decreased from 1.51 kW·m⁻²·s⁻¹ to 1.03 kW·m⁻²·s⁻¹. Additionally, the CMP demonstrated enhanced thermal stability, making the pyrolysis activation energy E_α increase from 135.04 to 191.97 kJ/mol during 308~416 °C by pyrolysis kinetics. Compared to composite PLA incorporating pristine MPP, the CMP-modified counterpart exhibits superior mechanical properties and significantly enhanced hydrophobicity, evidenced by a maximum water contact angle reaching 93.96°. It provides a strategy for adapting phosphorus-based flame retardants for PLA, thereby broadening their applicability across diverse scenarios. Full article

Background/Objectives: Self-medication (SM) is a global public health phenomenon with both benefits and risks. Evidence on its determinants remains inconsistent, particularly among university students, and limited in Central and Eastern Europe despite high OTC availability and variable health literacy. This study aimed to assess SM behaviors among health sciences students and identify sociodemographic and health-related determinants of OTC use. Methods: The cross-sectional CAWI survey was conducted between November 2024 and March 2025 among 435 students of the Medical University of Warsaw selected through purposive sampling. Univariable and multivariable logistic regression analyses were performed in the study population to characterize respondents practicing SM. Detailed analyses of SM behaviors included only respondents reporting self-medication (n = 278; 64.2%). Associations between sociodemographic and health-related characteristics and selected SM behaviors were assessed using the chi-square (χ²) test, with false discovery rate correction applied using the Benjamini–Hochberg procedure. Questionnaire reliability was confirmed using Cohen’s kappa coefficients ranging from 0.63 to 1.00. Statistical significance was set at p < 0.05. Results: The most commonly used medicines were analgesics (97.5%), vitamins (54.7%), and antipyretics (48.2%). Adjusted multivariable analysis showed that the odds of SM were higher among women (AOR = 4.11, 95% CI = 2.11–8.02), Emergency Medical Services students (AOR = 3.57, 95% CI = 1.45–8.75), master’s degree students (AOR = 3.45, 95% CI = 1.96–5.88), and students living in large cities with more than 500,000 inhabitants (AOR = 2.63, 95% CI = 1.43–5.00). Motivations, perceived benefits, risks, and adherence to package leaflet instructions differed significantly by respondent characteristics. Conclusions: SM behaviors are influenced by sociodemographic and health-related factors. Targeted education on rational OTC use, professional responsibility, and critical appraisal of health information is needed. Safe SM practices among health sciences students may support their future role in promoting responsible self-medication. Full article

Background: Organ-preservation strategies in locally advanced rectal cancer (LARC) increasingly require accurate assessment of response to neoadjuvant therapy, yet magnetic resonance imaging poorly distinguishes complete from near-complete responses. We investigated plasma sphingolipid dynamics across multiple treatment timepoints as monitoring biomarkers for pathological response. Methods: This single-centre cohort study included 86 patients with histologically confirmed LARC; 58 received neoadjuvant treatment followed by surgical resection with an evaluable Mandard tumour regression grade (TRG) and formed the response-evaluable cohort (19 good responders [TRG 1–2], 39 poor [TRG 3–5]). Plasma sphingomyelin (SM), sphingosine-1-phosphate and glucosylceramide were quantified by UPLC–MS/MS at baseline (M0), post-chemoradiotherapy (M1) and post-surgery (M2). Discrimination was assessed by receiver operating characteristic analysis and odds ratios, longitudinal trajectories by a linear mixed-effects model, and SM was compared head-to-head with serum carcinoembryonic antigen (CEA). Results: SM did not discriminate response at baseline (M0 AUC = 0.53) but did after treatment (M1 AUC = 0.750, p = 0.024; M2 AUC = 0.786, p = 0.010; pooled AUC = 0.767; odds ratio 10.67 at a 164.0 mg/L cutoff; negative predictive value 84%). SM correlated inversely with TRG grade (Spearman ρ = −0.43, p = 0.016) and outperformed serum CEA (AUC 0.74 vs. 0.60). Trajectories diverged over time (mixed-model time × group interaction p = 0.023) with no baseline difference (p = 0.96): good responders increased SM by +22.5% from M0 to M2, whereas poor responders declined by −8.4%. Conclusions: Plasma SM is not a pre-treatment predictor but emerges as a post-treatment monitoring biomarker for pathological response in LARC, supporting its integration into multimodal response assessment for organ-preservation decision-making. External validation in independent cohorts is warranted. Full article

The series-connected chain MMC with DC-blocking capacitor (C-SCMMC) is an emerging topology for HVDC tapping applications with high voltage and relatively low power capacity. However, the DC-blocking capacitor can be bulky and costly, which deteriorates its economy and flexibility. This paper investigates the feasibility of DC-blocking capacitor reduction, with special emphasis on the characteristics, control, and parameter design. The principle of C-SCMMC considering the DC-blocking capacitor dynamics is firstly modeled and analyzed, and the ripples and harmonics, as well as their influences on the external performance of the converter, are analyzed; then, improved control strategies, namely, the grid-tied harmonics suppression and current control, are proposed considering the enlarged DC-blocking capacitor voltage ripple; after that, the influence of reduced DC-blocking capacitor on the operation range and parameter design are analyzed, and the economic advantage is demonstrated via parameter design and comparison based on a typical bench mark. Analysis shows that the DC-blocking capacitor voltage ripple is coupled with other parameters, such as the arm output voltage and SM capacitance, and the advised range is from 0.1 to 0.3 p.u. at unity power factor to reduce the overall cost. In a typical design, the C-SCMMC can reduce the number of SMs by 2/3 and the capacitor energy storage capacity by 15% compared to the conventional MMC. Finally, simulation results obtained in MATLAB/Simulink 2024b are provided to verify the feasibility of the proposed converter and the correctness of the parameter design. Full article

The primary control mechanism for synaptic uptake of GABA is through γ-aminobutyric acid transporter 1 (GAT-1, SLC6A1), a known target for anti-epileptic drugs. Although there is a clinically used GAT-1 inhibitor, tiagabine, the development of a new ligand with an advanced pharmacological profile is desirable. For this purpose, a multi-tiered virtual approach to screening has been created, involving pharmacophore-based search; application of the Informational Spectrum Method for Small Molecules, followed by EIIP/AQVN filtering (ISM-SM); molecular docking using an ensemble of several experimentally obtained structures of GAT-1; and ADMET predictions. Pharmacophore-based screening of the ZINC database of natural products, combined with ISM-SM/EIIP filtering, yielded 237 candidate compounds. Structural separation analysis discriminated between the positives and negatives, enabling enrichment-based prioritization. The use of a composite normalized rank score based on docking affinity and structural similarity allowed for the identification of the top candidates: ZINC03643214 and ZINC67840571. Collectively, these refinements establish a more sophisticated computational model for identifying novel GAT-1 inhibitors and highlight promising candidates for future experimental evaluation. Full article

In this paper, a high-sensitivity sub-zero temperature sensor based on the Mach–Zehnder interferometer coated with organic silicone film is proposed. The sensor is fabricated by polishing four orthogonal sides in the multimode fiber (MMF) of the single-mode–multimode–single-mode (SMS) structure with a CO₂ laser and then coating the structure with a mixed film of hydroxyl-terminated siloxane and methyl MQ silicone resin to form a sub-zero-sensitive layer. The sub-zero temperature sensitivity of the coated sensors is experimentally compared for samples with different numbers of polished facets. The experimental results show that the sub-zero temperature sensitivity of the sensors with one to four polished facets increased from 0.73 nm/K to 2.15 nm/K in the temperature range of 223 K to 273 K. The fiber sub-zero sensor has the advantages of compact structure, high sensitivity and low cost, which lead to the potential for application in fields such as biomedicine, aerospace and energy. Full article

Myogenic differentiation is a powerful mechanism for generating diverse cell types from fibroblasts. Here, we show that targeted suppression of β-actin by RNA interference in human fibroblasts triggers coordinated molecular and structural changes consistent with trans-differentiation toward SMC-like phenotype. This conversion is marked by upregulation of smooth muscle differentiation markers (α- and γ-smooth muscle actins, SM22, smooth muscle myosin, desmin, vinculin) at mRNA and protein levels, together with distinct morphological alterations: increased cell area, loss of polarity, and reorganization of the actin cytoskeleton. Notably, β-actin-downregulated fibroblasts exhibited a focal adhesion architecture that differed from parental fibroblasts. These findings indicate that β-actin downregulation may provide a novel in vitro method to induce SMC-like differentiation, with potential implications for vascular biology and tissue engineering. Full article