Search Results (331)

This paper proposes a co-design methodology for the power and control stages of a bidirectional battery charger/discharger based on a boost converter topology. The approach ensures safe operation by limiting the battery current derivative, preventing abrupt transients that could degrade battery lifespan. The control strategy combines a cascade structure with an inner sliding mode current controller (for robustness and fast response) and an outer adaptive PI voltage loop (to regulate the DC-link voltage under varying load conditions). Additionally, the design constrains the switching frequency to reduce power losses. Experimental validation on a prototype converter demonstrates the effectiveness of the co-design framework, showing precise current/voltage regulation, adherence to switching frequency limits, and compliance with battery charging/discharging requirements. The results highlight the methodology’s potential to enhance efficiency and reliability in energy storage systems. The dynamic restrictions, overshoot lower than 5%, settling time shorter than 5 ms, and a battery current limitation less than 50 A/ms were always met with SMC and, in some cases, with the PI controller, but the results with SMC were always better: lower overshoot, shorter settling time, and greater restriction on the derivative of the battery current. In addition, the SMC system was 2.5–5.0% more efficient than the PI controller. Full article

This paper presents a flipped-voltage-follower low-dropout regulator (FVF-LDO) for power supply rejection enhancement and low-power operation in CMOS transimpedance amplifiers for optical receiver applications. The proposed FVF-LDO ensures high stability and reliable regulation over a wide range of load conditions by employing a flipped-voltage follower for fast local feedback and improved power supply rejection, while a super-source follower enhances the transient response through increased current-driving capability. A bandgap reference with a 3-bit trimming DAC is adopted to compensate process variations and support stable LDO operations, achieving a temperature coefficient of 19.6 ppm/°C over a wide range of −25 °C to 125 °C. The FVF-LDO exhibits a 101 mV undershoot under a 100 µA-to-10 mA load step with a 100 ns edge time. When applied to an optoelectronic inverter-based active-feedback transimpedance amplifier (TIA), the regulated supply improves the power supply rejection ratio (PSRR) from −6 dB to −38.3 dB. The proposed optoelectronic TIA realized in a 180 nm CMOS process achieves 67 dBΩ transimpedance gain, 869 MHz bandwidth, 66 dB dynamic range, 6.68 pA/√Hz input-referred noise current spectral density, and 4.68 mW power consumption from a single 1.8 V supply. The proposed TIA chip occupies a core area of 940 × 162 µm². Full article

The increasing penetration of Doubly Fed Induction Generator (DFIG)-based wind energy systems raises major concerns regarding voltage stability and Fault Ride-Through (FRT) capability under grid disturbances and wind speed variations. This paper proposes a coordinated control framework for a grid-connected DFIG system, where a Static Synchronous Compensator (STATCOM) based on discrete-time deadbeat current control is integrated with a Supercapacitor Energy Storage System (SCES) connected to the DC link through a bidirectional DC-DC converter governed by cascaded Active Disturbance Rejection Control (ADRC). The deadbeat-controlled STATCOM provides fast reactive current injection for voltage support during sag and swell events, while the cascaded ADRC enhances DC-link voltage regulation and suppresses rotor-speed oscillations. Comprehensive MATLAB/Simulink simulations are carried out under variable wind speed and severe grid disturbances up to 80% voltage sag and 50% voltage swell. For voltage regulation, the proposed method is compared with SVC and PI-based STATCOM. In addition, SCES control performance is evaluated by comparing PI, single ADRC, and cascaded ADRC in terms of DC-link voltage overshoot, undershoot, and ripple. The results show clear improvements in voltage response and transient performance. Under a 20% voltage sag, the proposed deadbeat-controlled STATCOM significantly improves the dynamic response, where the undershoot is reduced from 0.125 p.u. (with SVC) to 0.04 p.u., and the settling time is shortened from 0.04 s to 0.025 s. Under a severe 80% sag, the overshoot is limited to 0.02 p.u., compared with 0.13 p.u. for the SVC and 0.15 p.u. for the PI-based STATCOM. Similarly, under a 50% voltage swell, the overshoot is reduced to 0.20 p.u., compared with 0.46 p.u. for the SVC and 0.27 p.u. for the PI-based STATCOM. Regarding the DC-link performance under 80% sag, the proposed cascaded ADRC-based SCES limits the overshoot and undershoot to 6 V and 2 V, respectively, compared with 39 V and 32 V for the PI-based SCES. These results confirm the superior damping, disturbance rejection, and FRT enhancement achieved by the proposed strategy. Full article

Oxidative stress disrupts protein function through direct oxidation and triggers adaptive post-translational modifications. Among these, small ubiquitin-like modifier (SUMO)-ylation mediates fast and reversible remodeling of nuclear and cytoplasmic proteins. Redox regulation of the SUMO E1–E2 conjugation complex and specific SUMO proteases, such as SENP1 and SENP3, allows ROS to influence SUMO turnover and substrate selectivity. This defines SUMOylation as a versatile stress-response module under oxidative stress. In this review, we describe oxidative stress-induced remodeling of SUMO conjugation and deconjugation, with a focus on SUMO2/3 responses that transiently adjust transcription, DNA damage repair, and nuclear body dynamics. We discuss disease-relevant SUMO targets and pathological alterations in SUMO regulation across four major disease categories: neurodegenerative diseases, cardiovascular disease, cancer, and diabetes/metabolic diseases. In addition, we summarize emerging evidence connecting redox-sensitive SUMO remodeling to germ-cell function and reproductive health. Together, these perspectives highlight the dual role of SUMOylation as both a driver of stress adaptation and a tractable target for informing therapeutic strategies targeting the SUMO pathway. Full article

Experimental investigations and datasets in the open literature remain scarce for the fast transient response of air systems induced by sudden internal structural failures, hindering rigorous experimental validation of the governing trends associated with multiple influencing factors. To address this gap, we establish a fast transient air-system test platform and develop a step boundary simulation device based on mechanical energy storage, enabling rapid and repeatable boundary transients. The experiments demonstrate that the minimum boundary-change time is less than 6 ms, satisfying the simulation requirement for boundary transients associated with typical sudden structural failures (≤10 ms). Guided by a dimensionless analysis, we conduct fast transient cavity-venting experiments under varying outlet areas, cavity geometric parameters, and initial pressure ratios, thereby obtaining the transient response data of the cavity pressure. In parallel, we simulate the test process using a three-dimensional numerical approach validated against the experiments; by combining experimental and numerical results, we systematically analyze the effects of key factors on the fast transient response during cavity venting and elucidate the underlying mechanisms. This paper provides experimentally validated data and a reliable experimental methodology for studying fast transient response processes in air systems, and it supports the passive safety design of aero-engines. Full article

Grid-forming (GFM) battery energy storage system (BESS) inverters are becoming a cornerstone of resilient microgrids, where severe voltage sags and abrupt operating shifts can challenge both voltage regulation and controller stability. Finite-set model predictive control (FS-MPC) offers fast transient response and multi-objective coordination, yet conventional designs rely on static cost-function weights that are typically tuned offline and may become suboptimal under disturbance-driven regime changes. This paper proposes a forecast-guided KAN-adaptive FS-MPC framework that (i) formulates the inner-loop predictive control in the stationary αβ frame, thereby avoiding PLL dependency and mitigating loss-of-lock risk under extreme sags, and (ii) introduces an Operating Stress Index (OSI) that fuses load forecasts with reserve-margin or percent-operating-reserve signals to quantify grid vulnerability and trigger resilience-oriented control adaptation. A lightweight Kolmogorov–Arnold Network (KAN), parameterized by learnable B-spline edge functions, is embedded as an online weight governor to update key FS-MPC weighting factors in real time, dynamically balancing voltage tracking and switching effort. Experimental validation under high-frequency microgrid scenarios shows that, under a 50% symmetrical voltage sag, the proposed controller reduces the worst-case voltage deviation from 0.45 p.u. to 0.16 p.u. (64.4%) and shortens the recovery time from 35 ms to 8 ms (77.1%) compared with static-weight FS-MPC. In the islanding-like transition case, the proposed method restores the PCC voltage within 18 ms, whereas the static baseline fails to recover within 100 ms. Moreover, the deployed KAN governor requires only 6.2 μs per inference on a 200 MHz DSP, supporting real-time embedded implementation. These results demonstrate that forecast-guided adaptive weighting improves transient resilience and power quality while maintaining DSP-feasible computational complexity. Full article

Kv4.2 channels are the principal mediators of the fast transient outward K⁺ current (I_tof) in the heart and the A-type current (I_A) in the nervous system, both of which play a relevant role in shaping cardiac action potentials and neuronal excitability. This review focuses on how interactions with ancillary subunits, such as potassium channel interacting proteins (KChIPs) and dipeptidyl peptidase-like proteins (DPPs), beyond regulating trafficking, membrane expression, and gating properties of Kv4.2 channels, significantly influence channel drug response, demonstrating that Kv4.2 does not represent a fixed pharmacological entity but rather a dynamic macromolecular complex whose drug responsiveness depends on its subunit composition. Understanding this accessory subunit-dependent modulation is important, as the pharmacological profile of Kv4.2-containing channels may differ depending on the predominant accessory subunit composition in each tissue. Full article

The integration of photovoltaic (PV) generation with bidirectional electric vehicle (EV) fast-charging systems offers a promising pathway toward sustainable transportation and grid support. However, the dynamic coupling between maximum power point tracking (MPPT) perturbations and grid-side power quality presents a fundamental challenge in such multi-converter architectures. This paper addresses this challenge through a coordinated design and optimization framework for a grid-connected, PV-assisted bidirectional off-board EV fast charger. The system integrates a 184.695 kW PV array via a DC-DC boost converter, a common DC link, a three-phase bidirectional active front-end rectifier with an LCL filter, and a four-phase interleaved bidirectional DC-DC converter for the EV battery interface. A comparative evaluation of three MPPT algorithms establishes the Fuzzy Logic Variable Step-Size Perturb & Observe (Fuzzy VSS-P&O) as the optimal strategy, achieving 99.7% tracking efficiency with 46 μs settling time. However, initial integration of this high-performance MPPT reveals system-level harmonic distortion, with grid current total harmonic distortion (THD) reaching 4.02% during charging. To resolve this coupling, an Artificial Bee Colony (ABC) metaheuristic algorithm performs coordinated optimization of all critical PI controller gains. The optimized system reduces grid current THD to 1.40% during charging, improves DC-link transient response by 43%, and enhances Phase-Locked Loop (PLL) synchronization accuracy. Comprehensive validation confirms robust bidirectional operation with seamless mode transitions and compliant power quality. The results demonstrate that system-wide intelligent optimization is essential for reconciling advanced energy harvesting with stringent grid requirements in next-generation EV fast-charging infrastructure. Full article

Background: Genetic causes of growth failure should be suspected in patients born small for gestational age (SGA) who fail to show postnatal catch-up growth, present with severe short stature (SS), and exhibit a poor or absent response to growth hormone (rhGH) therapy. Mutations in the insulin-like growth factor 1 receptor (IGF1R) gene are associated with impaired growth, intrauterine growth restriction (IUGR), low birth weight and/or length, and postnatal SS. Case Description: A 9-year-old boy, born SGA for birth length, was evaluated for severe SS. Common causes of SS were excluded. At 9 years and 7 months of age, his height was 112.6 cm (−3.99 SDS), weight 18 kg (−3.79 SDS), and BMI 14.2 kg/m² (−1.8 SDS); pubertal development was Tanner stage 1. The target height was 158 cm (−2.62 SDS). Bone age was delayed by approximately one year compared with chronological age. Serum IGF-1 levels were within the upper-normal range for age. GH therapy (0.035 mg/kg/day) was initiated due to the lack of catch-up growth in an SGA subject. After three years of treatment, the height gain was only 0.5 SDS. IGF-1 levels showed a transient treatment-related increase, followed by persistent normalization during ongoing therapy. Next-generation sequencing (NGS) analysis identified novel heterozygous paternal nonsense variant in the IGF1R gene: c.3498C>G (p.Tyr1166Ter). At 12 years of age, impaired fasting glucose and reduced glucose tolerance were detected; consequently, it was decided to discontinue rhGH therapy, also in light of the IGF1R mutation and the lack of height recovery. Conclusions: This case underlines the critical role of genetic testing in the evaluation of patients born SGA. The coexistence of SGA status and an IGF1R gene mutation may provide a clear explanation for both the poor response to rhGH therapy and the increased risk of alterations in glucose metabolism. An extensive narrative review of the literature on growth outcomes and glucose metabolism abnormalities during GH treatment in SGA patients carrying IGF1R variants was also performed. Full article

This paper presents a systematic experimental comparison of three sliding-mode-based current control strategies—traditional sliding mode control (SMC), fast terminal sliding mode control (FTSMC), and super-twisting sliding mode control (STSMC)—applied to a grid-connected five-level active neutral point clamped flying capacitor (5L-ANPC-FC) inverter. Unlike existing studies that typically investigate a single controller or topology, this work provides a fair, hardware-validated benchmark under identical operating conditions, enabling a clear assessment of convergence speed, harmonic performance, robustness, and implementation complexity. All controllers are designed within a unified framework and their stability is rigorously analyzed using Lyapunov theory. Experimental evaluations are conducted under steady-state operation, step changes in reference current, grid-voltage sag/swell, and DC-link voltage variations. The results demonstrate that while all three controllers ensure robust current tracking and inherent DC-side capacitor voltage balancing without additional control loops, FTSMC achieves the lowest grid-current total harmonic distortion (THD) and fastest convergence. STSMC effectively suppresses chattering, and traditional SMC offers a simple yet reliable baseline solution. The presented findings provide practical design guidelines for selecting appropriate sliding-mode controllers in high-performance multilevel inverter applications. Among the assessed control techniques, FTSMC has the most rapid dynamic response, characterized by a rise time of 0.1 ms and a minimal grid-current THD of 1.95%, indicating exceptional steady-state and transient performance. STSMC markedly diminishes chattering and ripple, attaining a THD of 2.04% with enhanced waveform smoothness relative to traditional SMC. Conversely, traditional SMC offers a more straightforward implementation but demonstrates elevated ripple and THD levels of around 2.29%, along with a peak current inaccuracy of 6–8%. The results underscore the trade-offs between implementation simplicity, dynamic responsiveness, and harmonic performance of the evaluated control techniques. Full article

Ultrafast spin dynamics is a core research focus for advancing ultrafast spintronic devices, yet its accurate quantitative probing remains a challenge with conventional time-resolved techniques. Herein, we employ double-pump optical pump–terahertz emission spectroscopy (OPTE) to investigate the ultrafast spin dynamics of a Pt/Gd₁₉(Co_0.8Fe_0.2)₈₁/Ta ferrimagnetic rare-earth–transition-metal heterostructure. Experimental measurements resolve a single-step ultrafast demagnetization process with a characteristic time of ~0.42 ± 0.02 ps, followed by two-stage magnetic recovery involving a fast relaxation and a slow relaxation process. The fast and slow recovery time constants show a distinct positive dependence on the control pump fluence, increasing from 2.49 ± 0.11 ps to 3.28 ± 0.03 ps and 57.36 ± 11.28 ps to 164.96 ± 1.61 ps, respectively, as the pump fluence rises from 0.80 to 1.19 mJ/cm². The ~0.42 ps demagnetization timescale is consistent with that of 3d transition metals, indicating the transient magnetic response of the low-Gd-concentration heterostructure is dominated by the CoFe sublattice. Our findings validate that OPTE is an effective approach for the quantitative characterization of electron–lattice–spin coupling processes in spin-based heterostructures and provide critical experimental insights for controllable manipulation of ultrafast spin dynamics, laying a foundation for the design of ultrafast terahertz spintronic devices. Full article

This paper presents a quadruple step-down (QSD) trans-inductor voltage regulator (TLVR) converter to accommodate the high-current and fast-transient requirements of processor power supplies. Evolved from dual-step-down (DSD) topology, the QSD configuration offers stronger load capacity; three additional flying capacitors are introduced between adjacent phases to break the 25% duty cycle constraint, thereby extending the output voltage range and accelerating the transient response. Moreover, the converter’s transient response is optimized to its full potential through both multi-phase simultaneous operation and the incorporation of the dedicated TLVR architecture. A modified adaptive on-time (AOT) controller supporting four-phase simultaneous operation is employed. Designed and verified via post-layout simulation in a 180 nm BCD process with all 6 V power transistors, the converter achieves a peak efficiency of 96.1% at 24 V input and 3 V output, as well as a maximum load capacity of 20 A. Under a 19 A load current step with a 19 ns rise time, it exhibits only a 37 mV output voltage droop and a 2 μs settling time, even with a 100 μF output capacitor. Full article

Prostate cancer (PCa) progression is critically driven by androgen receptor (AR) signaling, which integrates hormonal cues with metabolic programs supporting tumor growth, survival, and therapy resistance. Emerging evidence suggests that intermittent fasting (IF) and related dietary interventions—such as time-restricted eating (TRE), alternate-day fasting (ADF), and fasting-mimicking diet (FMD)—modulate systemic metabolism, including reductions in insulin and insulin-like growth factor 1 (IGF-1), and induce intracellular nutrient stress that can influence AR activity, splice variant expression (e.g., AR-V7), and downstream metabolic pathways. This systematic literature review (Scopus, PubMed, Web of Science; publications up to December 2025; search terms: “prostate cancer,” “androgen receptor,” “AR splice variants,” “intermittent fasting,” “fasting mimicking diet”, “metabolism,” “therapy resistance”) summarizes preclinical and clinical studies addressing the impact of IF on AR signaling, lipogenesis, mitochondrial function, redox homeostasis, and therapy response. Preclinical studies indicate that IF can reduce AR expression, impair nuclear translocation, modulate AR splice variants such as AR-V7 via nutrient-sensitive splicing mechanisms, and enhance sensitivity to androgen deprivation therapy and AR-targeted agents. Mechanistically, IF-induced metabolic stress engages AMP-activated protein kinase (AMPK), mechanistic target of rapamycin (mTOR), and sirtuin pathways, alters lipid and mitochondrial metabolism, and transiently increases reactive oxygen species (ROS), creating vulnerabilities in prostate tumor cells. Translational evidence suggests potential benefits of integrating IF with standard therapy, but effects may depend on fasting regimen, caloric intake, macronutrient composition, and patient metabolic context, including risk of lean mass loss. This review highlights the metabolic crosstalk between IF and AR signaling and emphasizes the need for future clinical studies incorporating biomarker-guided approaches and body composition monitoring to fully exploit this intersection for improved therapeutic outcomes in prostate cancer. Full article

Precise and smooth actuation is a central requirement in surgical robotics, where small tracking errors or oscillations can directly affect task quality and safety. This paper studies the control of an induction-motor-driven surgical joint using a sliding-mode strategy enhanced by fractional-order operators and implemented within a DTC–SVM structure. The motivation is to improve motion smoothness and disturbance rejection without sacrificing the fast dynamic response offered by direct torque control. A dynamic model of the actuator is developed by combining the electrical equations of the induction motor with the mechanical dynamics of a robotic joint, including inertia, viscous friction, gravity-induced torque, and Coulomb friction. Fractional-order sliding surfaces are introduced for both position and flux regulation, and the closed-loop stability is examined through Lyapunov-based arguments. Simulation results show accurate trajectory tracking with limited overshoot and smooth transient responses. The motor speed remains well regulated, while stator flux and currents stay within admissible bounds. The electromagnetic torque adapts to load variations with reduced ripple, and the rotor pulsation remains bounded. Within the limits of numerical evaluation, these results indicate that the proposed fractional-order sliding-mode DTC–SVM scheme is suitable for precision-oriented surgical robotic actuation. Full article

Silicon carbide (SiC) detectors continue to emerge as a promising technology for applications requiring radiation hardness, fast response times, and stable operation in harsh environments. In this work, the charge-collection dynamics of ultra-thin membrane SiC detectors are investigated through time-dependent TCAD simulations, consistent with previously reported measurements. The study analyzes the transient response following the localized generation of electron–hole pairs induced by ions, comparing bulk and membrane detector geometries with identical active-layer thicknesses. Two-dimensional simulations provide a time-resolved characterization of the electron and hole current-density distributions within the active region of the device. The results show that both device architectures present a transient current signal featuring two main components. Despite similarities in the prompt drift-driven signal component, the SiC membrane response is characterized by a short secondary component returning to zero within 3.5 × 10^–10 s at zero external bias, making it well-suited for reliable single-ion detection. In contrast, bulk devices exhibit a markedly different response, characterized by a significantly more intense and prolonged secondary component followed by a long tail that does not return to zero within the simulation time window for all investigated reverse biases. This tail is the result of the collection of carriers generated in the substrate that reach the depletion region through diffusion-driven processes. These findings contribute to the optimization of SiC-based solid-state detectors for quantum-technology device fabrication, demonstrating that the removal of the substrate drastically reduces the diffusion-dominated current component, thereby ensuring precise timing and minimal charge loss. Full article