Search Results (402)

Salinity is a major environmental constraint that influences nutrient acquisition and internal transport in coastal plant species. However, the electrophysiological mechanisms underlying nutrient flow regulation in mangroves remain poorly understood. This study investigates the active transport flow of nutrients (NAF) and nutrient plunder capacity (NPC) in two ecologically significant mangrove species, Aegiceras corniculatum (L.) Blanco (A. corniculatum) and Kandelia obovata Sheue, H.Y. Liu & J.W.H. Yong (K. obovata), using intrinsic electrophysiological leaf traits including inherent impedance (IZ), inherent capacitive reactance (IXC), inherent inductive reactance (IXL), and inherent capacitance (IC). A randomized block design was employed using three different saline treatments with control, such as control (0 mM), low (T1,100 mM), medium (T2, 250 mM), and high (T3, 450 mM). The results of the fitting equations show a positive correlation between resistance (Re), capacitive reactance (XC), and inductive reactance (XL) with clamping force (CF); all values of R² are ≥0.98, and p-values are <0.0001. Nutrient transport capacity (NTC) was non-significant in control and low-salt treatment for both mangrove species, indicating resistance to low levels of salt stress. NAF results of A. corniculatum showed a slight reduction of 7.9% under low salinity, while K. obovata displayed strong positive responses NAF increasing by 63.7% compared to the control. Additionally, the NPC of A. corniculatum species was not significantly affected at low and medium salt levels but declined at high salt levels. In contrast, K. obovata exhibited a higher growth rate and better photosynthetic performance than A. corniculatum. Our findings provide novel mechanistic insights into how electrophysiological regulation governs nutrient transport under salinity stress and highlight interspecies differences in adaptive strategies, with implications for understanding mangrove resilience in saline environments. Full article

STC2 (stanniocalcin 2) controls calcium (Ca²⁺) homeostasis in human platelets and other cell lines. The regulation of intracellular Ca²⁺ homeostasis is crucial for platelet activation; thus, the alteration in intracellular Ca²⁺ concentration or the mechanism involved in its regulation has been proposed to underlie some thrombotic disorders. Our previous studies evidenced that the knockdown of STC2 altered murine platelet activation; furthermore, a reduction in STC2 expression resulted in enhanced Ca²⁺ homeostasis in diabetic patients and, therefore, would contribute to the prothrombotic condition as a hallmark of diabetes mellitus type 2 (DM2). In this study, we examine a possible link between the expression of stanniocalcins (STCs) and different thrombotic events in humans. The expression of STCs was determined by Western blotting (WB); meanwhile, the analysis of protein interaction and phosphorylation was performed by completing a previous immunoprecipitation protocol (IP) of the proteins of interest. Thus, our results from patients with stroke/ictus presented a clear reduction in STC2 expression in their platelets, finding less STC2 content in the youngest thrombotic patients. Furthermore, acetyl-salicylic acid (ASA) administration reversed the decrease in the expression of STC2 in patients who did not suffer additional thrombotic episodes, as evidenced by the longitudinal analysis of up to 10 years of follow-up. Additionally, the increase in STC2 phosphorylation at the serine residues revealed increased activity of STC2 in thrombotic patients. Finally, we suggest that store-operated Ca²⁺ entry (SOCE) is over-activated in patients suffering from stroke/ictus, as revealed by the increase in the STIM1/Orai1 interaction found under resting conditions and, further, because MEG-01 cells transfected with siRNA STC2 to evoke artificial reduction in the STC2 expression presented an increased SOCE with respect to the control cells transfected with siRNA A. Conversely, the expression of the non-capacitative Ca²⁺ channels, Orai3 and TRPC6, was found to be reduced in patients with stroke. Altogether, our data allow us to conclude that STC2 represents a promising marker of stroke/ictus in thrombotic patients. Full article

Microphysiological systems (MPSs) have emerged as alternatives to animal testing in drug development, following the FDA Modernization Act 2.0. Double-layer channel-type MPS chips with porous membranes are widely used for modeling various organs, including the intestines, blood–brain barrier, renal tubules, and lungs. However, these chips faced challenges owing to optical interference caused by light scattering from the porous membrane, which hinders cell observation. Trans-epithelial electrical resistance (TEER) measurement offers a non-invasive method for assessing barrier integrity in these chips. However, existing electrode-integrated MPS chips for TEER measurement have non-uniform current densities, leading to compromised measurement accuracy. Additionally, chips made from polydimethylsiloxane have been associated with drug absorption issues. This study developed an electrode-integrated MPS chip for TEER measurement with a uniform current distribution and minimal drug absorption. Through a finite element method simulation, electrode patterns were optimized and incorporated into a polyethylene terephthalate (PET)-based chip. The device was fabricated by laminating PET films, porous membranes, and patterned gold electrodes. The chip’s performance was evaluated using a perfused Caco-2 intestinal model. TEER levels increased and peaked on day 5 when cells formed a monolayer, and then they decreased with the development of villi-like structures. Concurrently, capacitance increased, indicating microvilli formation. Exposure to staurosporine resulted in a dose-dependent reduction in TEER, which was validated by immunostaining, indicating a disruption of the tight junction. This study presents a TEER measurement MPS platform with a uniform current density and reduced drug absorption, thereby enhancing TEER measurement reliability. This system effectively monitors barrier integrity and drug responses, demonstrating its potential for non-animal drug-testing applications. Full article

High parasitic capacitance from poly-insulator-poly capacitors in complementary metal oxide semiconductor (CMOS) processes presents a major bottleneck to achieving high-resolution successive approximation register (SAR) analog-to-digital converters (ADCs) in imaging systems. This study proposes a Phase-Adjustable SAR ADC that addresses this limitation through a reconfigurable architecture. The design utilizes a phase-adjustable logic unit to switch between a conventional SAR mode for high-speed operation and a noise-shaping (NS) SAR mode for high-resolution conversion, actively suppressing in-band quantization noise. An improved SAR logic unit facilitates the insertion of an adjustable phase while concurrently achieving an 86% area reduction in the core logic block. A prototype was fabricated and measured in a 0.35-µm CMOS process. In conventional mode, the ADC achieved a 7.69-bit effective number of bits at 2 MS/s. By activating the noise-shaping circuitry, performance was significantly enhanced to an 11.06-bit resolution, corresponding to a signal-to-noise-and-distortion ratio (SNDR) of 68.3 dB, at a 125 kS/s sampling rate. The results demonstrate that the proposed architecture effectively leverages the trade-off between speed and accuracy, providing a practical method for realizing high-performance ADCs despite the inherent limitations of non-ideal passive components. Full article

In the shift toward sustainable energy, there is a strong demand for efficient and durable energy storage solutions. Supercapacitors, in particular, are a promising technology, but they require high-performance materials that can be produced using simple, eco-friendly methods. This has led researchers to investigate new materials and composites that can deliver high energy and power densities, along with long-term stability. Herein, we report a green synthesis approach to create a composite material consisting of reduced graphene oxide and silver nanoparticles (rGO/Ag). The method uses ascorbic acid, a natural compound found in fruits and vegetables, as a non-toxic agent to simultaneously reduce graphene oxide and silver nitrate. To enhance electrochemical performance, the incorporation of silver nanoparticles into the rGO structures is optimized. In this study, different molar concentrations of silver nitrate (1.0, 0.10, and 0.01 M) are used to control silver nanoparticle loading during the synthesis and reduction process. A correlation between silver concentration, defect density in rGO, and the resulting capacitive behavior was assessed by systematically varying the silver molarity. The synthesized materials exhibited excellent performance as supercapacitor electrodes in a three-electrode configuration, with the rGO/Ag 1.0 M composite showing the best performance, reaching a maximum specific capacitance of 392 Fg⁻¹ at 5 mVs⁻¹. Furthermore, the performance of this optimized electrode material was investigated in a two-electrode configuration as a coin cell device, which demonstrates a maximum areal-specific capacitance of 22.63 mFcm⁻² and a gravimetric capacitance of 19.00 Fg⁻¹, which is within the range of commercially viable devices and a significant enhancement, outperforming low-level graphene-based devices. Full article

Low-emissivity (Low-E) glass, crucial for thermal insulation, significantly attenuates wireless signals, hindering 5G communication. Metasurface technology offers a solution, but the existing designs often neglect the etching ratio constraint and lack physical interpretability. In this work, we propose a physically constrained search method that incorporates prior knowledge of the capacitive equivalent circuit to guide the design of metasurfaces on Low-E glass. First, the equivalent circuit type of the metasurface is determined as a capacitive structure through transmission line model analysis. Then, a random walk-based search is conducted within the solution space of topological patterns corresponding to capacitive structures, ensuring etching ratio constraints and maintaining structural continuity. Using this method, we design a metasurface pattern optimized for 5G communication, which demonstrates over 30 dB improvement in signal transmission compared with full-coating Low-E glass. A fabricated 300 mm × 300 mm prototype, etched with a ratio of 19.5%, demonstrates a minimum transmission loss of 2.509 dB across the 24–30 GHz band with a 3 dB bandwidth of 4.28 GHz, fully covering the 5G n258 band (24.25–27.5 GHz). Additionally, the prototype maintains a transmission coefficient reduction of no more than 3 dB under oblique incidence angles from 0° to 50°, enabling robust 5G connectivity. Full article

Ultrathin oxide semiconductors are promising channel materials for next-generation thin-film transistors (TFTs), but their performance is severely limited by bulk and interface defects as the channel thickness approaches a few nanometers. In this study, we show that high-pressure hydrogen annealing (HPHA) effectively mitigates these limitations in 3.6 nm thick ZnO TFTs. HPHA-treated devices exhibit a nearly four-fold increase in on-current, a steeper subthreshold swing, and a negative shift in threshold voltage compared to reference groups. X-ray photoelectron spectroscopy reveals a marked reduction in oxygen vacancies and hydroxyl groups, while capacitance–voltage measurements confirm more than a three-fold decrease in interface trap density. Low-frequency noise analysis further demonstrates noise suppression and a transition in the dominant noise mechanism from carrier number fluctuation to mobility fluctuation. These results establish HPHA as a robust strategy for defect passivation in ultrathin oxide semiconductor channels and provide critical insights for their integration into future low-power, high-density electronic systems. Full article

Background/Objectives. Despite growing interest in capacitive-resistive electric transfer TECAR) and Vibration therapy (VT), their comparative effectiveness in sports recovery remains unclear. This study aimed to evaluate and contrast the short-term effects of TECAR and VT on neuromuscular recovery following eccentric muscle fatigue, relative to passive rest, in active young adults. We hypothesized that both interventions would accelerate recovery and potentially reduce injury risk. Methods. Forty-one participants were randomized into two groups: TECAR therapy (Group 1) and VT (Group 2). Neuromuscular function was assessed at baseline, post-exercise, and post-intervention using tensiomyography (TMG) and electromyography (EMG). Results. Both groups showed a significant increase in EMG MDF intercept after exercise. Post-intervention, VT induced a further rise in this parameter, whereas TECAR stabilized values without significant change. In the contralateral resting limb, increases persisted after exercise and passive recovery. Between-limb differences were significant only in the TECAR group. TMG analysis revealed a non-significant but large-effect increase in contraction delay (Td) post-exercise, followed by significant reductions after both interventions. In the left limb, Td changes were not significant. For maximal displacement (Dm), both VMO and VLO muscles demonstrated a significant decrease post-exercise and a marked recovery after both therapies. Other TMG parameters (Ts, Tc, Tr) showed no significant changes. Conclusions. Both TECAR and VT effectively enhanced neuromuscular recovery after eccentric exercise. TECAR demonstrated a modest but consistent advantage, particularly in normalizing muscle recruitment and restoring mechanical properties, making it suitable in contexts requiring rapid recovery. VT, however, remains a more accessible and cost-effective modality. These findings support the application of both techniques in sports recovery, while highlighting the need for further research in professional athletes and diverse exercise settings to optimize regeneration strategies and reduce injury risk. Full article

The emissions from biomass combustion systems have recently been the subject of increased attention. In addition to elevated concentrations of particulate matter and hydrocarbons (HCs) in the flue gas, significant levels of NO_x emissions occur depending on the used fuel, such as biogenic residues. In response to legal requirements, owners of medium-sized plants (≈100 kW) are now also forced to minimize these emissions by means of selective catalytic reduction systems (SCR). The implementation of a selective sensor is essential for the efficient dosing of the reducing agent, which is converted to ammonia (NH₃) in the flue gas. Preliminary laboratory investigations on a capacitive NH₃ sensor based on a zeolite functional film have demonstrated a high sensitivity to ammonia with minimal cross-influences from H₂O and NO_x. Further investigations concern the application of this sensor in the real flue gas of an ordinary wood-burning stove and of combustion plants for biogenic residues with an ammonia dosage. The findings demonstrate a high degree of agreement between the NH₃ concentration measured by the sensor and an FTIR spectrometer. Furthermore, the investigation of the long-term stability of the sensor and the poisoning effects of SO₂ and HCl are of particular relevance to the laboratory measurements in this study, which show promising results. Full article

Power transformers are critical components in electrical power systems, where failures can cause significant outages and economic losses. Traditional maintenance strategies, typically based on offline inspections, are increasingly insufficient to meet the reliability requirements of modern digital substations. This work presents an integrated multi-sensor monitoring framework that combines online frequency response analysis (OnFRA^® 4.0), capacitive tap-based monitoring (FRACTIVE^® 4.0), dissolved gas analysis, and temperature measurements. All data streams are synchronized and managed within a SCADA system that supports real-time visualization and historical traceability. To enable automated fault diagnosis, a Random Forest classifier was trained using simulated datasets derived from laboratory experiments that emulate typical transformer and bushing degradation scenarios. Principal Component Analysis was employed for dimensionality reduction, improving model interpretability and computational efficiency. The proposed model achieved perfect classification metrics on the simulated data, demonstrating the feasibility of combining high-fidelity monitoring hardware with machine learning techniques for anomaly detection. Although no in-service failures have been recorded to date, the monitoring infrastructure is already tested and validated through laboratory conditions, enabling continuous data acquisition. Full article

This work presents a high-common-mode-rejection-ratio (CMRR) and high-gain FinFET-based bio-potential amplifier with a novel CMRR reduction technique. In this paper, a feedback buffer is used alongside a capacitively coupled chopper-stabilized circuit to reduce the common-mode signal gain, thus boosting the overall CMRR of the circuit. The conventional pseudoresistor in the feedback circuit is replaced with a tunable parallel-cell configuration of pseudoresistors to achieve high linearity. A chopper spike filter is used to mitigate spikes generated by switching activity. The mid-band gain of the chopper-stabilized amplifier is 42.6 dB, with a bandwidth in the range of 6.96 Hz to 621 Hz. The noise efficiency factor (NEF) of the chopper-stabilized amplifier is 6.1, and its power dissipation is 0.92 µW. The linearity of the parallel pseudoresistor cell is tested for different tuning voltages (V_tune) and various numbers of parallel pseudoresistor cells. The simulation results also demonstrate the pseudoresistor cell performance for different process corners and temperature changes. The low cut-off frequency is adjusted by varying the parameters of the parallel pseudoresistor cell. The CMRR of the chopper-stabilized amplifier, with and without the feedback buffer, is 106.9 dB and 100.3 dB, respectively. The feedback buffer also reduces the low cut-off frequency, demonstrating its multi-utility. The proposed circuit is compatible with bio-signal acquisition and processing. Additionally, a machine learning-based arrhythmia diagnosis model is presented using a convolutional neural network (CNN) + Long Short-Term Memory (LSTM) algorithm. For arrhythmia diagnosis using the CNN+LSTM algorithm, an accuracy of 99.12% and a mean square error (MSE) of 0.0273 were achieved. Full article

In this paper, 8 mol% yttria cubic stabilized zirconia (8YCSZ) composites with reduced graphene oxide (rGO) contents up to 10 vol% were consolidated by spark plasma sintering (SPS) at two different temperatures with the aim of evaluating the relationship of their electrical properties with the graphene content, the rGO crystallinity, and the microstructural features. Successful in situ reduction of GO was accomplished during SPS, and highly densified composites with homogeneous rGO distribution, even at the highest contents, were obtained. The electrical properties were analyzed using impedance spectroscopy. Measurements were taken up to 700 °C, revealing an inductive response for the composites with 5 and 10 vol% rGO and a capacitive response for the composites with 1 and 2.5 vol% rGO. The results indicate that, along with the ionic conduction typical of zirconia, there are additional polarization mechanisms associated with the presence of graphene at ceramic grain boundaries that substantially modify the impedance response. A minor electronic conductivity contribution was identified in the composites below the percolation threshold. These characteristics make the 8YCSZ composites promising candidates for application as SOFC components, as ceramic interconnects when the graphene content is above the percolation threshold, or as electrolytes when the graphene content is below this limit. Full article

A new approach is presented to elucidate the phenomena that occur within a porous single-walled carbon nanotubes (SWCNTs) modified glassy carbon electrode (GCE) and that influence the electrochemical behavior of the modified electrode. By employing cyclic voltammetry, reverse pulse voltammetry, and double potential step chronoamperometry, insights into the structural changes in the electrochemical double layer and the mass transport regimes are gained. An analysis of the reduction of the electrochemically generated [Fe(CN)₆]³⁻ shows that the SWCNTs layer can be considered inactive. However, their pronounced influence on the electrochemical signal arises from their capacitive behavior. Furthermore, a novel criterion for distinguishing the mass transport domains is proposed, which allows the estimation of the points at which a change in the mass transport regime occurs. The results also show the role of the porous SWCNTs layer in preventing the expansion of the double layer as well as in the process of ion condensation in the Gouy-Chapman layer. Finally, the counterintuitive and unexpected voltametric behavior, such as the independence of the current peak heights from the ionic strength of the support, the parabolic dependence of the peak potential on the scan rates, and the occurrence of steady-state currents, are discussed. Full article

In this study, a green hydrothermal synthesis method was employed to produce Mn₃O₄ and Mn₃O₄/β-MnO₂ nanostructures using EET-50, an organic extract obtained from a by-product of Carménère wine production. The biomolecules in EET-50 acted as reducing agents due to their electron-donating functional groups, enabling nanostructure formation without the need for additional chemical reductants. Morphological characterization by SEM revealed that a KMnO₄/EET-50 mass ratio of 3:1 led to the synthesis of nano-octahedra alongside rod-like structures, with shorter reaction times favoring the development of isolated nano-octahedra ranging from 100 nm to 170 nm. Structural analyses by XRD and Raman spectroscopy confirmed the formation of mixed-phase Mn₃O₄/β-MnO₂ and Mn₃O₄ (hausmannite). Electrochemical performance tests demonstrated that Mn₃O₄ nano-octahedra exhibited a superior specific capacitance of 236.27 F/g at 1 mA/g, surpassing the mixed-phase sample by 28.3%, and showed excellent capacitance retention (99.98%) after 100 cycles at 8 mA/g. Additionally, the Mn₃O₄ nano-octahedra exhibited enhanced oxygen evolution reaction performance in alkaline media, with an overpotential of 0.430 V vs. RHE and a Tafel slope of 205 mV/dec. These results underscore the potential of Mn₃O₄ nano-octahedra, synthesized via a green route using grape pomace extract as a reducing agent, offering an environmentally friendly alternative for applications in energy storage and electrocatalysis. Full article

Parallel-type slew-rate enhancers (PSREs) improve the driving capability of operational transconductance amplifiers (OTAs) for large capacitive loads. While capacitive-boosting (CB) techniques enhance PSRE efficiency in fully-differential designs, their application to single-ended configurations—common in off-chip load driving—remains unexplored. This work identifies a critical limitation of standard CB in single-ended unity-gain buffers: severe slew-rate degradation due to large common-mode input swings. To overcome this, we propose a novel split CB (SCB) technique for single-ended PSREs that strategically divides the boosting capacitance. Simulated in a 0.18-µm CMOS process, the proposed method achieves a ×5.53 reduction in settling time compared to standard CB when driving a 1-nF load. With only 4 µA quiescent current under a 3.3-V supply, it attains a 1% settling time of 2.56 µs for 2.64-V steps, demonstrating robust performance across process-voltage-temperature variations. This technique enables low-power, high-speed interfaces for drivers of off-chip devices. Full article