Search Results (547)

This paper presents an open-source miniaturised readout device designed for the wireless interrogation of passive LC sensors and wireless power transmission. The system is based on a Sparkfun RedBoard Artemis microcontroller with a custom-printed circuit board as an extension, providing a compact, low-cost alternative to expensive laboratory-grade equipment. The reader coil is excited by a signal that can be tuned digitally in both frequency and amplitude. The resonance frequency of a wirelessly coupled LC tank is detected by monitoring the voltage minimum of a rectified signal envelope, which corresponds to the impedance change of the reader inductance at resonance. Experimental validation demonstrates that the device accurately tracks resonance frequency shifts resulting from variations of the LC tank’s capacitance, performing comparably to laboratory-grade impedance analysers. Testing the influence of axial separation between the two coils up to 25 $\mathrm{m}$$\mathrm{m}$ showed stable and identifiable voltage dips. The programmable excitation signal peak-to-peak voltage ranges from $0.81$ V to $5.35$ V. The device enables fully stand-alone operation with a display and navigation switch, making it suitable for untethered LC wireless sensing and actuation applications. Full article

Invasive candidiasis caused by drug-resistant Candida species represents a critical global health challenge, with few novel therapeutic scaffolds under development. Here, silver nanoparticles were synthesized using a 21-day fermented Chun Mee kombucha tea extract (K-AgNPs) and characterized by UV-Vis spectroscopy, transmission electron microscopy, nanoparticle tracking analysis, and Fourier-transform infrared spectroscopy. LC-MS/MS profiling of the kombucha substrate documented a phytochemical landscape dominated by epigallocatechin (up to 122,631 µg/mL) and epigallocatechin gallate (up to 415 µg/mL), with a progressive ~80% decline in epicatechin and concomitant increases in gallic acid and chlorogenic acid across the 21-day fermentation. K-AgNPs obtained were spherical, 19.4 nm (±7.9 nm SD) in diameter, with a surface plasmon resonance peak at 415 nm. FTIR confirmed phenolic, carboxylate, and glycosidic surface capping. Antifungal susceptibility testing against eight Candida species, including the WHO critical–priority pathogen Candidozyma auris, showed concordant minimum inhibitory and minimum fungicidal concentrations of 0.80–1.60 µg/mL, confirming fungicidal activity. In vivo evaluation in Galleria mellonella larvae across six infection models demonstrated that K-AgNP treatment at the species-specific MIC significantly improved larval survival versus untreated infected controls (p < 0.01–0.001), while nanoparticle-only groups maintained ≥98% survival, indicating negligible toxicity. Co-treatment amplified total hemocyte mobilization, and K-AgNP-only larvae maintained hemocyte viability above 96% at all time points, indistinguishable from negative controls. Together, these findings demonstrate antifungal activity of K-AgNPs across the genus Candida in standardized in vitro and in vivo settings and provide justification for further investigation, including head-to-head comparison against licensed antifungals and physicochemical validation of nanoparticle stability under assay conditions. Full article

To address the issues of low voltage levels and insufficient reliability in dynamic regulation and voltage stabilization in existing high-voltage power supplies for electron-curtain accelerators, this paper presents a 150 kV/30 kW DC high-voltage power supply specifically designed for electron-curtain accelerators. The main circuit employs an LC high-frequency resonant topology and a step-up transformer with eight secondary windings, utilizing a parallel step-up and series output architecture to increase the output voltage level. During the charging phase, a dual-closed-loop frequency conversion scheme combined with duty cycle feedforward is employed to accelerate charging speed, while the voltage stabilization phase utilizes hysteresis burst control to improve accuracy. Simulation results indicate that the system can charge to 155 kV in 102 ms, with a voltage ripple less than 0.1%, a linear regulation of 0.01%, and a load regulation of 0.5%. Tests on a low-voltage prototype confirmed that the power devices can achieve zero-current soft switching, with a resonant current peak of 40 A and overall efficiency reaching 96%. The accompanying filament power supply can stably output 24 V/20 A, and the closed-loop voltage regulation is stable and reliable, providing technical support for the engineering application of high-voltage power supplies in high-power electron beam accelerators. Full article

Antibiotic resistance and biofilm-associated infections require sustainable antimicrobial platforms that combine efficacy with biocompatibility. Fermented matrices are attractive for green nanomaterial production because they provide reducing metabolites and surface-active capping compounds. Rooibos kombucha is a polyphenol-rich fermentation system with potential to serve as a biosynthetic matrix for silver nanoparticles (AgNPs). The present work aimed to develop a rooibos kombucha-enabled platform for the green biosynthesis of phytochemical-capped silver nanoparticles, AgNPs-K, and evaluate their antibacterial, antibiofilm, and in vivo activity. Rooibos kombucha was fermented for 14 days and profiled by liquid chromatography–tandem mass spectrometry (LC–MS/MS). AgNPs-K were generated using kombucha extract and AgNO₃, purified, and characterized by ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and nanoparticle tracking analysis. Antibacterial activity against eight Gram-positive and Gram-negative reference pathogens was assessed by EUCAST-based microdilution and time-kill assays. Biofilm inhibition was measured by the crystal violet assay. In vivo toxicity and therapeutic efficacy were evaluated in Galleria mellonella larvae. AgNP formation was confirmed by a surface plasmon resonance (SPR) peak at 415 nm. TEM showed predominantly spherical nanoparticles with a main size range of 20–30 nm, a hydrodynamic diameter of 98 nm, and a zeta potential of −14.62 ± 0.04 mV. AgNPs-K showed overlapping minimum inhibitory concentration and minimum bactericidal concentration values of 1.14 µg/mL for Gram-positive species and 1.33 µg/mL for Gram-negative species. Time-kill assays showed rapid bactericidal activity after threshold concentrations were reached, with sustained suppression at 24 h. Biofilm formation was abolished at 40 µg/mL and strongly reduced at lower concentrations. AgNPs-K were non-toxic up to 400 µg/mL and improved survival in six of seven infection models. Fermented rooibos kombucha functions as an effective biosynthetic matrix for the green production of phytochemical-capped AgNPs. The resulting nanoparticles combine low-dose antibacterial and antibiofilm activity with favorable in vivo tolerability and efficacy, supporting fermentation-enabled nanobiotechnology strategies against biofilm-associated infection. Full article

In industrial applications such as in situ leaching and uranium mining, permanent magnet synchronous motors (PMSMs) for submersible pumps are frequently connected to frequency converters via long cables. During this long-distance transmission, traveling wave reflections induced by high-frequency pulse width modulation (PWM) generate severe transient overvoltages that threaten motor insulation. Because installation space at deep-well motor terminals is severely restricted, overvoltage suppression must be implemented at the inverter output. Here, the parameter design and optimization of a passive LC filter specifically developed for 250 Hz high-frequency PMSMs are presented. The optimal inductance and capacitance parameters were determined by balancing multiple operational constraints, including fundamental voltage drop, high-frequency harmonic attenuation, and the avoidance of low-order harmonic resonance. Furthermore, the anti-saturation performance of the magnetic core material, evaluated thermal characteristics through electromagnetic-thermal co-simulation, and analyzed the risk of self-excited oscillation between the filter capacitors and the motor was analyzed. Finally, hardware experiments conducted on a 20 m cable test bench validate that the designed LC filter effectively mitigates terminal overvoltage. The peak terminal voltage was reduced from 900 V to 505 V, and total harmonic distortion (THD) was limited to below 5%. This design provides a highly reliable, space-efficient solution for overvoltage suppression in high-speed, long-cable motor drive systems. Full article

The western honey bee (Apis mellifera) is increasingly exposed to environmental stressors that affect redox homeostasis, leading to imbalances in cellular functions. Natural bioactive compound-based nutritional strategies show promise in reducing oxidative stress while preserving redox signaling. In this study, we investigated the chemical composition, cytotoxicity, and redox-modulating effects of an aqueous extract of the edible mushroom Agaricus bisporus on the AmE-711 honey bee cell line. High-resolution Orbitrap LC–MS analysis revealed a chemically diverse extract comprising polyols, organic acids, amino acids, phosphorylated sugars, nucleotide derivatives, phenolic, and lipid-related compounds. Among the identified metabolites were mannitol, malic acid, citric acid, glutamic acid, and uridine diphosphate N-acetylglucosamine, providing a biochemical basis for potential metabolic and redox-related activity. Cell viability assays demonstrated that A. bisporus extract exhibited no significant cytotoxicity under the experimental conditions. Electron paramagnetic resonance (EPR) spectroscopy with the TEMPONE spin probe showed that untreated cells exhibited only minimal signal reduction (4.20%), while treatment with the extract alone caused a moderate decrease (12.08%), indicating the absence of reductive stress. Oxidative stress induced by hydrogen peroxide resulted in a pronounced TEMPONE signal reduction (37.88%), whereas co-treatment with the A. bisporus extract substantially attenuated this effect, lowering the signal reduction to 15.34%. These findings suggest that the aqueous A. bisporus extract may help preserve basal redox activity while attenuating peroxide-induced oxidative stress in AmE-711 honey bee cells. Rather than acting as a potent radical scavenger, the extract appears to function as a mild redox modulator or stabilizer under the tested conditions, which may be beneficial for honey bee cellular redox balance. These results support further investigation of physiologically appropriate A. bisporus-based dietary supplements for mitigating oxidative stress in apicultural systems. Full article

Background: Hydroxysafflor Yellow A (HSYA), the major bioactive component from Carthamus tinctorius L., exerts significant protective effects against myocardial ischemia-reperfusion injury (MIRI). Mitophagy is pivotal in the pathological process of MIRI, yet the specific molecular mechanism underlying HSYA-mediated mitophagy regulation remains unclear. Objective: This study aimed to investigate the association between HSYA treatment and mitochondrial autophagy in murine MIRI and to explore the potential mechanistic role of the SIRT1-FOXO3-BNIP3 signaling pathway using functional loss-of-function and rescue experiments. These findings may provide preliminary evidence supporting the clinical translational potential in MIRI therapy. Methods: Mouse myocardial ischemia-reperfusion injury (MIRI) model and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced AC16 cardiomyocyte injury models were established. Metabolomics, molecular docking, and surface plasmon resonance (SPR) techniques were combined to screen the potential targets of HSYA. The SIRT1 inhibitor EX527 and SIRT1 siRNA were used to verify the underlying mechanism. Cardiac function, myocardial infarct size, mitochondrial function, the expression of autophagy-related proteins, and protein–protein interaction were detected and analyzed. Results: Compared with the MIRI group, HSYA significantly improved cardiac function in mice, as evidenced by increased left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) (p < 0.01), attenuated ST-segment elevation, and improved myocardial perfusion. HSYA also markedly reduced myocardial infarct size (p < 0.01) and serum levels of CK-MB, LDH, and cTnI (all p < 0.01) and ameliorated myocardial histopathological damage and mitochondrial ultrastructural integrity. Mechanistic studies revealed that HSYA significantly upregulated the expression of SIRT1, FOXO3, BNIP3, Beclin-1, and the LC3II/I ratio while downregulating p62 expression (p < 0.01), consistent with enhanced mitophagy-related activity. Furthermore, these protective effects were markedly attenuated upon SIRT1 inhibition or siRNA-mediated silencing, whereas HSYA intervention partially reversed these alterations. Additionally, co-immunoprecipitation (Co-IP) and pull-down assays demonstrated that HSYA promoted protein–protein interactions between SIRT1-FOXO3, FOXO3-BNIP3, and BNIP3-LC3B. Conclusions: These findings highlight that HSYA is associated with improved cardiac function, enhanced mitophagy-related activity, and upregulated SIRT1-FOXO3-BNIP3 signaling, providing robust experimental evidence for its clinical translational application in MIRI treatment. Full article

Spoof surface plasmon polaritons (SSPPs) offer a powerful way to confine and guide light at terahertz and gigahertz frequencies, but their functionality is typically locked by their static geometries. This study demonstrates the active tuning of SSPP resonances using nematic liquid crystals (LCs) integrated into metallic grating structures. Through full-wave numerical simulations, we show that both reorienting the LC director and inducing the nematic–isotropic phase transition enable the efficient modulation of the SSPP resonance frequency. In the terahertz regime, tuning ranges exceeding 150 GHz are achieved while preserving strong resonant absorption. For GHz-scale structures, we identify optimal configurations—such as partially dielectric-filled grooves topped with an LC layer—that overcome field confinement challenges and provide practical frequency shifts of several gigahertz. These results establish LCs as an effective tuning medium for reconfigurable SSPP devices for future applications in emerging THz and GHz photonics. Full article

Ketosis is one of the most economically significant metabolic disorders affecting periparturient dairy cows, causing production losses and predisposing animals to secondary complications. Current blood-based diagnostics are invasive and provide limited insight into the underlying metabolic perturbations. This study employed an integrated three-platform metabolomics approach to characterize milk metabolite alterations in ketotic Holstein dairy cows and to evaluate milk-based biomarker panels for early ketosis detection. Milk samples from 20 healthy control (CON) cows and 6 ketotic cows were collected at 2 weeks postpartum and analyzed by direct injection/liquid chromatography–tandem mass spectrometry (DI/LC-MS/MS), proton nuclear magnetic resonance (¹H-NMR) spectroscopy, and inductively coupled plasma mass spectrometry (ICP-MS). Ketosis was confirmed by serum β-hydroxybutyrate concentrations ≥ 1400 μmol/L. Principal component analysis, partial least squares-discriminant analysis, and receiver operating characteristic (ROC) curve analyses were applied. All three platforms discriminated ketotic cows from healthy cows, with clear cluster separation validated by 2000 permutation tests (p < 0.05). DI/LC-MS/MS identified 16 significantly altered metabolites (p < 0.05), with butyrylcarnitine (C4), phosphatidylcholine 30:0 (PC 30:0), ether-linked phosphatidylcholine O-38:3 (PC O-38:3), and citrulline identified as the top discriminatory biomarkers (AUC = 0.920; 95% CI: 0.85–0.98; sensitivity = 91.7%; specificity = 93.3%). ICP-MS revealed significantly reduced selenium (Se, p = 0.017), manganese (Mn, p = 0.045), and chromium (Cr, p = 0.037), as well as elevated cobalt (Co, p = 0.014) in ketotic milk (AUC = 0.870). ¹H-NMR detected no individually significant metabolites; however, multivariate analysis distinguished groups (AUC = 0.890), with succinate (numerical fold change: +5.77×; p = 0.059), methanol (−1.94×; not significant), and acetate (+2.88×; not significant) as top VIP contributors. The combined multi-platform biomarker panel (joint classification using top VIP features from all three platforms, without formal data fusion) achieved superior diagnostic performance (AUC = 0.970; 95% CI: 0.93–1.00; sensitivity = 95.0%; specificity = 96.7%). These findings identify coordinated perturbations in glycerophospholipid metabolism, acylcarnitine profiles, amino acid homeostasis, antioxidant mineral status, and energy metabolism during early ketosis, and suggest that milk metabolomics is a promising non-invasive approach for precision dairy health monitoring, pending validation in independent cohorts. We acknowledge the small ketotic group size (n = 6) as a limitation; therefore, these findings should be considered discovery cohort observations requiring prospective validation before clinical translation. Full article

The increasingly prominent “double-high” characteristics (high penetration of renewable energy and high proportion of power electronic devices) in modern power systems pose severe challenges to secure and stable operation, especially due to wideband oscillations induced by grid-connected inverters. In view of the fact that existing impedance modeling for grid-forming control often neglects the decoupling effect of the LC filter capacitor and the dynamics of inner voltage/current loops, leading to inaccurate characterization of mid-to-high frequency impedance, this paper aims to establish more accurate impedance models for grid-connected inverters and to develop effective oscillation mitigation methods accordingly. First, the harmonic linearization method is adopted to derive refined positive- and negative-sequence impedance analytical models for NPC inverters under both grid-following and grid-forming control. Second, simulation-based frequency scanning is conducted to validate the accuracy of the proposed models, and the differences in system resonance characteristics under the two control modes are comparatively analyzed. Finally, oscillation suppression strategies based on active damping and virtual impedance are, respectively, designed. The results show that the proposed models can accurately characterize mid-to-high frequency impedance, reveal the distinct resonance mechanisms of different control modes, and the proposed suppression strategies can effectively attenuate wideband oscillations. These findings provide theoretical foundations and practical technical pathways for stability analysis and optimization design of inverter-grid systems in high-renewable-penetration scenarios. Full article

This work presents a reliability-oriented design methodology for LC oscillators, focusing on Colpitts configurations implemented by a bipolar transistor. A nonlinear steady-state analytical framework is used as a practical design tool to determine the resonant tank parameters, loop gain conditions, and the dependence of oscillation amplitude on the operating conditions. Based on this analysis, a systematic sizing procedure is developed, in which the LC tank is designed and statistically characterized prior to amplifier and bias selection. The influence of component tolerances, temperature variation, supply voltage deviation, and load changes is quantified through statistical Monte Carlo analysis. To overcome the amplitude instability observed in the classical Colpitts topology, an automatic gain control (AGC) block is introduced that directly regulates the transistor transconductance, eliminating the need for individual amplitude adjustment. The simulation results demonstrate that, while the conventional Colpitts oscillator exhibits output amplitude variations of approximately ±30% under realistic parameter deviations, the proposed AGC-enhanced design limits worst-case amplitude variation to within ±10% using only standard tolerance components. A hardware prototype was developed to experimentally validate the methodology over wide variations in resonant tank parameters, amplifier bias conditions, and external load. The combined analytical, statistical, and experimental results confirm that the proposed approach simplifies the design process, improves robustness, and enables predictable, trimming-free oscillator operation suitable for mass-produced electronic systems. Full article

The high-density integration of low-temperature co-fired ceramic (LTCC) filters inevitably induces complex parasitic coupling. Traditional designs rely on forced isolation to mitigate this issue, often at the expense of increased physical footprints. To overcome this limitation, this paper proposes a strategy for the controlled utilization of parasitic effects. Methodologically, localized grounding structures are introduced to construct a controlled electromagnetic boundary. The system’s main path exhibits alternating inductive-capacitive (L-C) coupling, with a single explicit capacitive cross-coupling introduced between specific nodes (resonators 2 and 5). Based on the principle of multi-path signal cancellation, this explicit path synergizes with the implicit parasitic environment. By satisfying conditions of equal amplitude and a 180° phase difference at specific frequencies, a high-order hybrid network is equivalently reconstructed, generating four transmission zeros (TZs). A compact sixth-order LTCC filter was fabricated and tested. Measured results demonstrate a fractional bandwidth (FBW) of 38.6%, a shape factor of 1.16 (based on the 20-dB/3-dB bandwidth ratio), and a 20-dB upper stopband extending beyond $4.28f_0$. In conclusion, the rational utilization—rather than forced isolation—of inherent parasitic effects provides an effective solution for enhancing frequency selectivity and stopband performance in high-density integrated RF front-ends. Full article

Flat bands exhibit vanishing group velocity and marked sensitivity to lattice geometry, making them a useful setting for studying localization driven by destructive interference. In this work, electrical-circuit simulations are employed to investigate flat-band systems in one, two, and three dimensions. A one-dimensional two-band circuit is first considered, and its flat-band response is characterized through node-to-ground impedance spectra and steady-state voltage distributions. The analysis is then extended to two- and three-dimensional Lieb lattice circuits characterized by sublattice imbalance. In the two-dimensional Lieb circuit, the flat band touches the dispersive bands at a Dirac point, so hybridization with dispersive modes affects the observed localization. Under periodic boundary conditions, wave vector quantization also produces responses that depend on whether the number of unit cells is even or odd. By contrast, in the three-dimensional Lieb circuit, the flat band is spectrally isolated from the dispersive bands, allowing stronger spatial confinement and clearer sublattice selectivity. The one-dimensional, two-dimensional, and three-dimensional models therefore represent three different situations: a singular flat band, a flat band that touches dispersive bands, and a spectrally isolated flat band. Comparing these cases shows how different degeneracy conditions shape impedance responses and localization patterns in electrical circuit systems. At the flat band frequency, the localized voltage response can also be used to generate spatial patterns in both two-dimensional and three-dimensional circuits, pointing to a possible route for spatial mode control of compact localized states in electrical systems. Full article

Per- and polyfluoroalkyl substances (PFASs) in fluorinated firefighting wastewater (FFW), which are difficult to remediate using conventional technologies, represent a critical environmental hazard due to the extreme persistence and bioaccumulation potential of soil–groundwater systems. Niobium-supported boron-doped diamond (BDD) anodes were synthesized by microwave plasma chemical vapor deposition, and their performance in the electrochemical advanced oxidation processes (EAOPs) of FFW were systematically investigated. Under optimized conditions (100 mM Na₂SO₄ electrolyte with 100 mM peroxymonosulfate (PMS), current density of 33.3 mA/cm², pH = 6), the BDD anode achieved near-complete mineralization, with 92.5% total organic carbon (TOC) removal and significant defluorination (77.5% F⁻ release) within 240 min in simulated FFW-contaminated groundwater. For FFW-contaminated soil remediation, 90.2% TOC removal and 41.6% defluorination were achieved after 720 min under optimal treatment (water-to-soil ratio of 20:1). Quenching experiments and electron paramagnetic resonance (EPR) tests revealed that hydroxyl radicals (·OH) and singlet oxygen (¹O₂) were the predominant reactive species. Liquid chromatography–mass spectrometry/mass spectrometry (LC-MS/MS) analysis indicated that PFASs were removed by shortened carbon chains, ultimately mineralizing to CO₂ and F⁻. Toxicity assessment using Vibrio fischeri luminescence demonstrated a reduction in toxicity (from 99.8% to 20.9%), confirming the effective detoxification of BDD-based EAOPs. This work establishes BDD-based EAOPs as a promising technology for eliminating PFASs in groundwater and soil, offering theoretical insights into EAOPs and engineering solutions for PFAS remediation. Full article

Background and clinical significance: Autoimmune hepatitis (AIH) and ankylosing spondylitis (AS) are distinct immune-mediated disorders that only rarely coexist. Diagnostic interpretation becomes especially challenging when the liver biochemistry is not classically hepatocellular and the histology is unavailable. Case presentation: We report a 51-year-old man with inflammatory back pain, polyarthralgia, weight loss, fatigue, night sweats and fever. Laboratory tests showed marked systemic inflammation, anemia and a cholestatic-predominant liver profile with associated aminotransferase elevation. Imaging demonstrated bilateral sacroiliitis and syndesmophytosis. Liver workup excluded viral, obstructive, metabolic, hereditary and inflammatory bowel disease-associated cholangiopathic causes. Antinuclear antiboidies (ANA) and anti liver cyotsole 1 antiboidies (anti-LC-1) were positive, IgG was mildly elevated, magnetic resonance cholangio-pancreatography (MRCP) was negative for primary sclerosing cholangitis and the simplified AIH score was six. A liver biopsy was proposed but refused. The patient received a short course of prednisone for rheumatologic flare control, followed by nonsteroidal anti-inflammatory treatment and sulfasalazine, with normalization of liver tests during follow-up. Conclusions: This case is suggestive, but not diagnostic, of autoimmune hepatitis in a patient with ankylosing spondylitis. In the absence of histology and in the setting of a cholestatic-predominant biochemical profile, the findings may be more appropriately interpreted as an autoimmune hepatitis-like syndrome. The main teaching point is that abnormal liver tests in AS warrant structured evaluation beyond drug toxicity and viral hepatitis, particularly when autoimmune serology is positive, even in a cholestatic-predominant presentation. Full article