Search Results (899)

Targeted down-modulation of monocytes and macrophages is a promising strategy for controlling excessive inflammatory processes. Bacterial protein toxins are attractive pharmacological modulation tools for this purpose because of their potency and specificity. Here, we combined the specific properties of the two protein toxins C3lim from Clostridium limosum and CyaA from Bordetella pertussis in the preferentially monocyte/macrophage-targeting bioconjugate C2IN-C3lim_E174Q-Cys_His-AC. The enzymatically inactive and monocytic cell-targeting transporter C2IN-C3lim_E174Q-Cys was recombinantly produced and chemically coupled to the isolated adenylate cyclase (AC) domain of CyaA, which mediates down-modulation of monocytic cell functions through intracellular cAMP accumulation Within 1 h, the bioconjugate showed preferential cell association with monocytic cells relative to HeLa cells, which served as the non-target cell model, without impairing overall cellular viability. Intracellular enzymatic activity was successfully confirmed by significantly elevated cAMP levels in all target cell types. Moreover, in migration assays with primary human monocytes, the bioconjugate markedly reduced both general motility and targeted chemotaxis, demonstrating that the delivery of the enzyme moiety translates into a measurable functional response. Therefore, we conclude that the novel bioconjugate C2IN-C3lim_E174Q-Cys_His-AC enables preferential targeting of monocytes and macrophages under the experimental conditions investigated here and provides proof-of-concept for a targeted protein delivery platform for functional modulation of monocytic cells. Full article

This study proposes and implements a DCHC-based CRM/CCM hybrid control with a switching-period limit condition to improve light-load efficiency in an AC-coupled ESS power converter. In grid-connected ESSs, the operating point continuously varies depending on load and grid conditions, and particularly in the light-load region, switching losses become relatively dominant, which can degrade overall system efficiency. Furthermore, in the medium-to-high-load regions, increased current ripple and peak current can lead to greater device stress and conduction losses, making it difficult to simultaneously ensure both efficiency and reliability across the entire load range with a single operating mode. To address this issue, this study proposes an approach that generates the current reference based on a PR controller and combines it with a DCHC-based current control structure to flexibly switch the control mode according to operating conditions. The proposed method is designed to balance the loss factors by reducing switching losses through CRM operation under light-load conditions, while concurrently employing CCM operation as the load increases to limit current ripple and device current stress. Consequently, this study demonstrates the potential for high-efficiency operation of the power converter system by improving the control strategy at the single-phase inverter stage in an AC-coupled ESS environment, and the validity of the proposed method is confirmed through simulation and experiments. Full article

Chronic stress is a pervasive psychophysiological burden and an independent risk factor for chronic kidney disease (CKD). Large-scale cohort studies confirm that stress exposure significantly increases CKD risk and accelerates renal decline, even after adjusting for traditional confounders. However, the neuroendocrine mechanisms translating stress into direct kidney damage remain unclear. This review focuses on the brain–kidney axis, a bidirectional framework integrating neural, endocrine, and immune signals. Under chronic stress, sustained overactivation of the hypothalamic–pituitary–adrenal (HPA) axis and sympathetic nervous system (SNS), coupled with secondary renin–angiotensin–aldosterone system (RAAS) dysregulation, creates a deleterious intrarenal milieu. Unlike classical models driven by high salt or metabolic disorders, a proposed hallmark of stress-induced injury is the non-classical activation of the mineralocorticoid receptor (MR). Given MR’s equal affinity for cortisol and aldosterone, the protective barrier maintained by 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) is compromised under persistent glucocorticoid elevation. This may allow cortisol to escape inactivation and aberrantly activate intrarenal MR, a process putatively termed gluco-mineralo cross-activation. This mechanism is hypothesized to initiate profibrotic cascades via NADPH oxidase 4 (NOX4)/ROS/TGF-β/Smad pathways and amplifies the complement C5a-C5a receptor 1 inflammatory axis, culminating in fibrosis and sclerosis. Based on these insights, we propose stress-related kidney disease (SRKD) as a distinct clinical entity. This review synthesizes current evidence to guide precision interventions targeting the brain–kidney axis. Full article

Compared with conventional two-coil wireless power transfer (WPT) systems, three-coil WPT systems with an intermediate relay coil offer superior performance in terms of transmission distance and tuning flexibility, making them suitable for a wider range of applications. To address the CC/CV hybrid charging challenge in practical three-coil wireless power transfer (WPT) systems, based on the dual-frequency compensation network (DFCN), this paper proposes a dual-frequency switchable LCC-S-S and S-S-S compensated three-coil topology along with a systematic parameter tuning methodology. Furthermore, the proposed system exhibits zero-phase angle (ZPA) input impedance characteristics at both resonant frequencies, and the ZPA condition remains invariant under coupling coefficient variations. Unlike conventional approaches requiring additional active components, such as relays or AC switches, the proposed compensation topology realizes simple and efficient CC/CV hybrid charging by only switching between two resonant frequencies. An experimental prototype rated at 400 W is constructed to assess the efficacy of the presented framework. The system has a simple structure, is easy to control, and has stable output. The peak DC-DC efficiency reaches 92.15% and 92.75% in both the CC and CV charging modes, respectively. Full article

To address the problems of existing DC crosstalk fault detection methods, including complex procedures, difficult implementation, and potential insulation hazards, this paper proposes the crosstalk fault detection and location method based on variable bridge. First, by periodically switching the busbar-to-ground resistance through a variable-bridge circuit in one DC system, a low-frequency AC signal is injected into one busbar, while the bus voltage of another DC system is synchronously detected. If this low-frequency AC signal is present, it can be determined that a crosstalk fault exists between the two DC systems; this signal injection method avoids the insulation safety hazards caused by the coupling capacitor injection method. Subsequently, a method of alternating injection and detection between the two system sections is adopted to locate the crosstalk branch. Finally, the dual-frequency method is introduced; namely, AC signals of two different frequencies are injected and the impedance of the crosstalk loop is measured separately, and a system of two equations is established to solve for the crosstalk resistance. The simulation experiment results show that, whether positive–positive pole crosstalk or positive–negative pole crosstalk occurs, this method can accurately identify the crosstalk branch and measure the crosstalk resistance. Full article

Equipotential entry on ultrahigh voltage alternating current (UHV AC) transmission lines produces brief potential transfer current pulses with high amplitude. This study develops a coupled capacitance model that retains phase conductors A, B, and C, human body node M, and tower/ground reference G. Capacitances extracted with a three-dimensional quasi-electrostatic boundary element method (BEM) are incorporated into an electromagnetic transient (EMT) model with a cybernetic arc representation and explicit ignition and extinction logic. Under baseline conditions, the proposed model increased peak current by 2.281–2.985% and total specific energy by 10.189–12.868% relative to the traditional model. Coupling between the human body and the two nonworking phases contributed to the transient current balance at node M. Within the investigated configuration with an ideal source, phase-to-ground and phase-to-phase branch currents remained small relative to the peak transfer current. The calculated peak current and total specific energy were compared with reported 1000 kV tension tower measurements. Across the ranges examined in the sensitivity analysis, the values from the proposed model remained higher than the values from the traditional model, and total specific energy was most sensitive to the breakdown threshold and initial gap. Full article

Background: Dark fermentation (DF) of organic solid waste (OSW) is a promising route for sustainable biohydrogen (bioH₂) production, but it is often limited by slow interspecies electron transfer and by acidification of the medium. Promoting direct interspecies electron transfer (DIET) with conductive additives is a candidate strategy to intensify the process. Objective and methods: This study compares the effect of magnetite (Fe₃O₄), granular activated carbon (AC), and laboratory-synthesized nickel–iron-doped activated carbon (DC) on the DF of genuine post-consumer food waste. Batch assays were conducted in 2.1 L anaerobic reactors under mesophilic conditions (35 °C), in triplicate, using food waste as the substrate and raw UASB sewage sludge as a mixed inoculum, without pH control. Biohydrogen was quantified with a portable biogas analyzer and expressed as mL H₂/g COD removed; the additives were characterized by SEM–EDS, and yields were compared by one-way ANOVA with Tukey post hoc test (α = 0.05). Main findings: Additive type had a highly significant effect on biohydrogen yield (F(6,14) = 48.7; p < 0.001; η² = 0.954). DC at 4 g achieved the best performance, reaching 0.271 mL H₂/g COD removed (≈4.5-fold higher than the additive-free control) and COD removals of 65.8–72.4%, whereas magnetite produced only sporadic, non-reproducible gains and undoped AC gave a modest, consistent improvement. Excessive acidification (final pH 2.5–3.1), attributed to the accumulation of volatile fatty acids under the deliberately unbuffered conditions, was the main operational limitation and is interpreted as a conservative ceiling on the yields reported here. Prospects: Metal-doped carbonaceous materials emerged as the most robust and reproducible strategy for intensifying DF of food waste; future work should couple this route with pH buffering and with electrochemical and microbial-community analyses to confirm the DIET contribution and to support scale-up in integrated biorefineries. Full article

This paper proposes a physics-informed neural network (PINN)-based design optimization framework for a compact smart actuator motor in physical artificial intelligence (Physical AI) robotic systems, where artificial intelligence is integrated with sensing, actuation, and physical interaction to perceive and act in the real world. To improve integration density and joint compactness, a printed circuit board (PCB) stator axial-flux permanent magnet (AFPM) motor is adopted as a thin and highly integrated topology. Because its performance is strongly affected by coupled design variables, including outer diameter, PCB count, turns per slot, trace width, and magnet thickness, an efficient and physically consistent optimization method is required. The proposed framework constructs a finite element analysis (FEA)-based design database and trains a physics-reconstructed PINN surrogate model to predict torque and loss components. Unlike purely data-driven models, the proposed PINN reconstructs output power and efficiency using physical power-balance relations, thereby improving consistency among torque, loss, output power, and efficiency. The trained surrogate is coupled with the nondominated sorting genetic algorithm II (NSGA-II) to maximize torque and efficiency while minimizing AC loss under dimensional and performance constraints. The optimized candidates are further verified by high-fidelity FEA. The results demonstrate that the proposed framework provides an effective Physical AI-oriented design methodology for compact robotic smart actuators by integrating PCB stator AFPM motor topology, physics-informed learning, and multi-objective optimization. Full article

The offshore wind power transmission system based on a diode rectifier unit (DRU) high-voltage direct current (HVDC) faces DRU blocking under sending-end AC faults and DC overvoltage under receiving-end AC faults. To address these two types of AC fault scenarios, corresponding fault ride-through strategies are proposed. For sending-end AC faults, a fault ride-through strategy based on active voltage reduction of the receiving-end converter station is proposed. An active voltage reduction control loop based on DC current deviation is added before the original DC voltage control loop of the receiving-end converter station, so that the DC voltage can be adaptively reduced with the decrease in DC current during sending-end faults. Thus, the conduction condition of the DRU is satisfied, and wind power transmission is maintained. For receiving-end AC faults, a fault ride-through strategy based on source-side active power reduction is proposed. According to the coupling relationship between the DC voltage and the wind turbine outlet voltage, an active power reduction control loop based on the outlet voltage deviation is added before the active power control loop of the wind turbine grid-side converter. During receiving-end faults, each wind turbine actively reduces its active power output, thereby suppressing the DC-side power surplus from the source side. The effectiveness of the proposed strategies was further evaluated through comparative simulations. Taking the 50% voltage-sag cases as examples, the proposed strategy maintains the DC current and transmitted power at approximately 0.84 p.u. and 0.42 p.u., respectively, during the sending-end fault, whereas both decrease to zero under the traditional strategy. During the receiving-end fault, the proposed strategy limits the DC voltage to within 1.05 p.u. and stabilizes the sending-end and receiving-end transmitted powers at approximately 0.49 p.u., while avoiding sustained voltage and current oscillations. Full article

Nonlinear and asymmetrical loads in microgrids cause severe current distortion and phase unbalance, presenting critical challenges for grid-connected energy storage inverters. Conventional dq-frame Linear Active Disturbance Rejection Control (LADRC) suffers from two key limitations: bandwidth coupling between the observer and controller, and insufficient AC disturbance attenuation. To address these issues, an improved Quasi-Proportional Resonant-LADRC (QPR-LADRC) strategy is proposed for the inner current loop. First, by reconfiguring the disturbance feedback structure within the Linear Extended State Observer (LESO), observer bandwidth is decoupled from controller bandwidth, eliminating parameter tuning conflicts. Second, parallel QPR units tuned at 2ω₀ and 6ω₀ are integrated into the LESO state-error feedback loop to construct a QPR-LESO. This provides high selective gain for dq-frame AC ripples, enabling zero steady-state error tracking for negative-sequence components and dominant 5th/7th harmonics. Validated via MATLAB/Simulink and StarSim Hardware-in-the-Loop (HIL) testing, the proposed strategy restricts grid-connected current Total Harmonic Distortion (THD) below 2.7% (2.61%, 2.54%, and 2.63% for phases A, B, and C) under severe nonlinear and unbalanced loads. Compared with conventional PI and conventional LADRC schemes, it achieves maximum THD reductions of 1.68% and 3.43%, respectively, while maintaining three-phase current unbalance below 1.1%. Full article

Research on the coupling coordination relationship between land–use carbon emissions (LUCE) and ecosystem service value (ESV) is vital for achieving China’s “dual carbon” goals and advancing ecological civilization. Applying the carbon emission coefficient method, equivalent factor method, coupling coordination degree model, and Geographically and Temporally Weighted Regression (GTWR) model, this study examined spatiotemporal patterns of land–use changes, carbon emissions per unit area (ACE), and ecosystem service value per unit area (AESV) across China (excluding Xizang, Hong Kong, Macao, and Taiwan) from 2000 to 2020, along with their coupling relationship and driving forces. Results showed that grassland, forest, and cropland accounted for more than 70% of China’s land area, with a total land–use conversion area of 1.42 × 106 km². ACE increased while AESV generally decreased, both displaying strong spatial heterogeneity and agglomeration. The average Dagum Gini coefficients were approximately 0.70 for ACE and 0.58 for AESV. Coupling coordination degree mostly fluctuated around 0.20, rising initially and then falling, with distinct spatial variations in coordinated development types. Population density, Normalized Difference Vegetation Index (NDVI), and average elevation were negatively correlated with the synergistic effect between LUCE and ESV, whereas GDP density, annual precipitation, and average slope showed positive correlations. These findings provided theoretical support for formulating scientific land–use policies, optimizing carbon emission management, and implementing effective ecological protection measures. Full article

The multi-infeed short-circuit ratio (MSCR) is widely used to characterize the steady-state strength of AC receiving systems with multiple line-commutated converter high-voltage direct-current (LCC-HVDC) infeeds. Its rated-power denominator, however, does not describe the disturbance actually imposed during converter blocking, commutation failure, AC-fault clearing, or concurrent disturbances at neighboring infeeds. This paper introduces a unified disturbance-driven transient multi-infeed short-circuit ratio (UDTMSCR). Six quantities obtained from the fault trajectory—reactive-power deviation, active-power reduction, reactive-power ramp, disturbance energy, recovery duration, and a fault-class correction—are normalized and combined into an infeed disturbance term. Substitution of this term for rated power retains the original impedance-coupling structure of MSCR, weights each neighboring disturbance by a bounded participation coefficient, and thereby accounts for the severity and timing of local and neighboring disturbances. The denominator is further separated into local and mutual contributions, and percentile thresholds may be used for severity classification. Numerical evaluation comprises eight representative two-infeed cases and a 48-case parametric study of mutual-path impedance, neighboring-event delay, and neighboring-disturbance amplitude. For the eight cases, the Pearson and Spearman correlations between inverse UDTMSCR and the fault-side voltage peak are 0.979 and 0.976, compared with 0.193 and 0.246 for inverse MSCR. The corresponding values in the parametric study are 0.973 and 0.983 for inverse UDTMSCR and −0.294 and −0.310 for inverse MSCR. A peak-only transient index and a transient voltage severity index are included as additional references, and the sensitivity of the results to the disturbance weights, coupling weights, grading thresholds, event window, and record imperfections is quantified. These results show that the proposed index retains the engineering interpretation of MSCR while better reflecting fault severity, inter-infeed coupling, and recovery. Because the trajectories are generated by a reduced-order model, verification with detailed electromagnetic-transient models and field records remains necessary. Full article

Active voltage control in distribution networks depends on a sensing–decision–actuation chain that must remain effective as feeder topology, inverter participation, and telemetry quality change. Most multi-agent reinforcement learning controllers retain feeder-specific observation and action interfaces, and their behavior under imperfect telemetry is rarely tested under whole-graph transfer. This paper proposes GRAS-AVC, which is a zero-shot graph actor–critic framework with a permutation-equivariant shared actor, variable-size twin graph critics, droop-residual actions, and deployment-time AC power-flow risk screening. The 322-bus target feeder contributes no replay, gradient updates, risk fitting, or checkpoint selection. On an independent third-year ten-day test, GRAS-AVC reduces violating bus–time pairs from 7.455% under droop control to 2.723% (63.5% relative reduction). Against a matched edge-conditioned Graph-TD3 backbone, the GRAS actor lowers pooled exposure from 9.239% to 4.027%; after identical screening, GRAS-AVC lowers it from 3.896% to 2.723% while triggering 15.89 percentage points less often. Across information-matched tests spanning reconstructed missing telemetry, graph-correlated errors, gross bad data, a one-step delay, compound stress, and 50 paired announced reconfigurations, the frozen system maintains 63.1–63.6% droop-relative reductions and improves bus–time exposure in every seed. A selector-model audit records no false acceptance across 40 exact-and-bounded-mismatch condition–seed evaluations. GRAS-AVC therefore couples topology-aware policy inference with auditable physical screening for scalable sensing-to-control operation in DER-rich distribution networks. Full article

This article presents a low-cost, high-voltage excitation circuit (EC) for capacitive ultra-sonic transducers (CUTs) based on a dual-path architecture. The proposed design comprises two independent AC excitation channels (AC-branch) that share a regulated DC-bias voltage (DC-branch). The circuit was developed to satisfy a fundamental operational requirement of CUTs: simultaneous application of a static bias voltage and a time-varying drive voltage. Because the electrostatic force depends nonlinearly on the applied voltage, efficient first-harmonic actuation requires the superposition of DC and AC voltage components. To reach this objective, the circuit and the transducer must be treated as a coupled electrical, electrostatic, mechanical, and acoustic system. In the proposed implementation, the DC-branch uses a TL494-PWM controller, a TIP50 switching transistor, a step-up transformer, and a rectifier-filter stage to generate the high-voltage bias of up to 200 V_DC. Each AC-channel employs an LM3886TF amplifier followed by a 1:15 step-up transformer, enabling the generation of excitation signals of up 180 V_peak. A key feature of the proposed architecture is the electrical independence of the two AC-channels, which allows for distinct excitation frequencies with minimal mutual interference. Experimental validation, performed with and without ultrasonic loads, demonstrates the relation between excitation conditions and the acoustic performance of the CUTs. Full article

This study presents a numerical optimization framework for a micro pin-fin heat sink (MPFHS). Three-dimensional conjugate heat transfer and fluid flow are simulated using the commercial CFD code CFD-ACE+. Coupled with the Levenberg–Marquardt method (LMM), the geometric parameters are optimized to minimize the base wall temperature T_bw under a constant total fin-volume constraint. The investigation assesses four pin-fin architectures—solid square (MPFHS-S), solid cylindrical (MPFHS-C), perforated square (MPFHS-S_P), and perforated cylindrical (MPFHS-C_P)—across five distinct fin-height distributions: uniform, constant-step (Design #1), increasing-step (Design #2), decreasing-step (Design #3), and hybrid-step (Design #4). The results demonstrate that perforated fins significantly enhance heat transfer by disrupting the thermal boundary layer and mitigating heat accumulation in the wake region. Within the allowable geometric constraints, larger perforation radii provide superior cooling performance. Among all examined configurations, the LMM-optimized Design #4 consistently achieves the lowest base temperature across the entire Reynolds number range. Specifically, for the MPFHS-C_P configuration, the optimized Design #4 yields T_bw values of 326.279 K, 311.617 K, and 309.142 K at Reynolds numbers of 200, 800, and 1200, respectively. As the Reynolds number increases, the temperature differences among the configurations gradually diminish, indicating that forced convection increasingly dominates the flow and reduces the sensitivity to fin geometry. Pressure-drop analysis reveals that perforated configurations incur an approximate 10–15% higher pressure loss compared to their solid counterparts. To evaluate the overall thermo-fluid behavior, the thermal performance factor η is employed to evaluate the trade-off between heat transfer enhancement and the associated pressure-drop penalty. The results confirm that cylindrical fins consistently outperform square fins, with perforations providing an additional reduction in T_bw. Overall, combining a hybrid fin-height distribution with perforated pin fins presents an effective strategy for optimizing MPFHS performance, offering practical guidelines for the thermal management of high-power electronic devices. Full article