Search Results (225)

To address head-end three-phase current unbalance and terminal power-quality deterioration caused by uneven three-phase load allocation in a low-voltage transformer area (LVTA), this paper proposes a DC-link-voltage-control-based phase-wise unbalanced power compensation strategy for a head-to-tail flexible interconnection structure embedded in the LVTA. The proposed structure consists of two three-phase four-leg converters sharing a common DC bus and connected to the head end and tail end of the LVTA, respectively. Different from conventional phase-wise compensation methods in which the DC side mainly acts as a power-transfer channel, the proposed strategy uses the DC-link voltage control of the head-end converter as the core of compensation power generation. Specifically, the outer DC-link voltage loop generates the total active compensation power, which is then allocated among the three phases according to the measured phase-power unbalance of the LVTA, thereby yielding the phase-wise compensation current references. Combined with phase-wise quasi-proportional-resonant current control, the compensation currents of different phase legs can be regulated without explicit positive-, negative-, and zero-sequence decomposition. Meanwhile, the tail-end converter adopts PQ control to support terminal power regulation and improve the terminal voltage quality of the LVTA. To provide a theoretical basis for the proposed method, a switching-cycle averaged model of the three-phase four-leg converter is established, and the leg-level phase-wise control characteristics are analyzed under the assumptions of a stiff DC link and symmetrical converter parameters. A control-oriented equivalent LVTA model is developed in MATLAB/Simulink. The proposed strategy is validated under steady-state unbalanced, RL load, load-disturbance, and equivalent feeder-impedance conditions. In addition, a conventional positive-, negative-, and zero-sequence compensation method is introduced as a benchmark for quantitative comparison. The simulation results demonstrate that the proposed method can effectively suppress the head-end three-phase current unbalance, maintain the DC-link voltage around its reference value, and improve the terminal voltage quality of the LVTA. Compared with the conventional sequence-component-based compensation method, the proposed strategy achieves effective unbalance mitigation while avoiding explicit sequence extraction and reducing the complexity of the compensation-current generation process. This study provides a feasible control framework for three-phase unbalance mitigation in flexible low-voltage transformer areas. Full article

The reliable operation of grid-connected distributed generation converters is challenged by severe unbalanced conditions and stringent fault ride-through requirements. To address these issues, this paper presents a sensorless flexible predictive direct power control (SF-PDPC) strategy for converters operating under severe asymmetrical grid faults. The proposed approach combines a frequency-adaptive neural network quadrature signal generator (FANN-QSG)-based virtual-flux estimator with a flexible power-reference generation scheme, enabling predictive control without grid-voltage sensors, conventional synchronization units, or cascaded filtering stages. The key feature of the proposed method lies in a flexible power-reference formulation that exploits the degrees of freedom associated with positive- and negative-sequence power components, allowing continuous regulation of the trade-off among current quality, active-power oscillations, and reactive-power oscillations under unbalanced grid conditions. This enables a unified control framework adaptable to different grid support objectives. The effectiveness of the proposed strategy is validated under a severe type-C voltage sag, grid frequency deviation, and harmonic distortion. Compared with the conventional PDPC, the proposed method reduces current total harmonic distortion from 57.78% to 0.44% while maintaining satisfactory active power tracking performance. Furthermore, the FANN-QSG-based estimator and the overall control structure demonstrate strong robustness under highly disturbed operating conditions. The proposed SF-PDPC enhances the operational flexibility of predictive power control for grid-connected converters operating under highly disturbed and unbalanced grid conditions. Full article

Background and Objectives: Schizophrenia in adolescence severely impairs quality of life (QoL) and disrupts critical social, academic, and neurodevelopmental periods. Beyond symptom remission, functional recovery and subjective well-being have become central therapeutic goals; however, the specific contributions of pharmacogenetic, social–cognitive, and residual clinical factors to QoL in early-onset schizophrenia remain largely unexplored. This study investigated the contribution of CYP2D6 metabolizer status, social cognition (theory of mind and empathy), residual psychopathology, and family factors to subjective QoL in adolescents with schizophrenia. Materials and Methods: A cross-sectional study of 52 adolescents with DSM-5 schizophrenia (PAT-SCZ) and 51 matched healthy controls. QoL was measured with the Pediatric Quality of Life Enjoyment and Satisfaction Questionnaire (PQ-LES-Q). Social cognition was assessed using the revised Reading the Mind in the Eyes Test (RMET). Residual symptoms were rated with the Positive and Negative Syndrome Scale (PANSS). CYP2D6 genotyping classified patients as normal metabolizers (NMs) or reduced-function metabolizers (RM: intermediate/poor). Two multivariable OLS regression models examined predictors of QoL. Results: Patients showed markedly lower QoL, impaired theory of mind, lower empathy, and higher residual symptoms than controls (all p < 0.0001). Within patients, reduced-function metabolizer (RM) status was associated with poorer QoL, weaker social cognition, higher negative/general psychopathology, and lower IQ. Two multivariable regression models explained 84.2–84.3% of the variance in QoL (adjusted R²). Social cognition (RMET scores) and CYP2D6 reduced-function metabolizer status emerged as the strongest predictors (β = 0.363 and β = −0.362, respectively, both p < 0.0001), followed by negative symptom severity and dysfunctional family relationships (all p < 0.05). Conclusions: Pharmacogenetic (CYP2D6), social–cognitive, and clinical factors strongly determine QoL in adolescent schizophrenia. Routine CYP2D6 genotyping, social-cognition remediation, and family interventions should be integrated into early treatment to improve long-term well-being. Full article

Background/Objectives: Antimicrobial resistance (AMR) in Escherichia coli is a growing public health concern, particularly in regions affected by environmental contamination and poor wastewater management. Data on locally isolated E. coli-targeting phages in Lebanon remain limited. This study aimed to isolate, characterize, and evaluate two lytic bacteriophages against AMR E. coli. Methods: Two phages, EPIMAM01 (gb:PQ493298) and EPIMRB01 (gb:PQ657784), were isolated from untreated sewage in Beirut using E. coli ATCC 25922. Characterization included double-layer agar assays, one-step growth analysis, and stability testing across temperature and pH ranges. Bacteriolytic activity was assessed in planktonic cultures and preformed biofilms. Host range and efficiency of plating (EOP) were evaluated using clinical isolates. Whole-genome sequencing and comparative analyses were performed. Results: Both phages produced clear plaques and showed a latent period of ~40 min. EPIMAM01 had a higher estimated burst size (140 PFU/infected cell) than EPIMRB01 (75 PFU/infected cell). Both phages remained stable between 4–50 °C and within a pH range of 5–10 but showed marked loss of activity at temperatures ≥60 °C and pH ≤3 or ≥12. EPIMAM01 effectively inhibited planktonic growth of E. coli ATCC 25922, whereas EPIMRB01 showed stronger biofilm-disrupting activity against preformed E. coli biofilms. Both phages lysed several of the 17 tested clinical E. coli isolates. Comparative analyses of gene presence/absence patterns, bacterial defense systems, and adsorption phenotypes among the tested E. coli strains identified mlaA, ydcQ, and ompD-2 as candidate adsorption-associated genes and suggested CRISPR systems may reduce susceptibility. Genomic analysis classified both phages as T4-like phages lacking lysogeny, virulence, or AMR genes. Conclusions: EPIMAM01 and EPIMRB01 are lytic phages with complementary antimicrobial properties, supporting their potential for further development as AMR control agents. Full article

Background/Objectives: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a major nosocomial pathogen. Although newer agents have reduced colistin use in high-income countries, this polymyxin remains important in many low- and middle-income settings. Colistin resistance in K. pneumoniae is most commonly associated with chromosomal alterations affecting the MgrB–PhoPQ pathway, or with plasmid-mediated mcr genes. This study aimed to investigate chromosomally mediated colistin resistance in CRKP clinical isolates from a Tunisian tertiary hospital. Methods: Between 2010 and 2015, 317 non-duplicate CRKP isolates were collected at Charles Nicolle Hospital, Tunis. Colistin MICs were determined by broth microdilution. Phenotypic tests and PCR characterized carbapenemases, extended-spectrum β-lactamases, AmpC, plasmid-mediated quinolone resistance, mcr and virulence genes. Porins (OmpK35/OmpK36) and the mgrB, phoP and phoQ loci were analyzed by SDS-PAGE and sequencing. Clonal relatedness was assessed by ERIC-PCR and multilocus sequence typing. We additionally compared colistin-resistant isolates with a panel of colistin-susceptible CRKP controls and assessed phenotypic stability after serial passages without colistin. Results: Five isolates (1.6%) were colistin-resistant. All were multidrug-resistant, produced OXA-48, and two also carried NDM-1. The isolates belonged to five distinct sequence types, including high-risk clones (ST11, ST101, ST147). No mcr genes were detected. Four isolates carried disruptive mutations in mgrB, and the remaining strain harbored inactivating mutations in both phoP and phoQ with an intact mgrB. Truncating alterations in PhoP/PhoQ and frequent loss or truncation of OmpK35/OmpK36 were observed. No mgrB/phoP/phoQ alterations were detected among colistin-susceptible controls, and colistin MICs remained stable after 7 days of drug-free passaging. Conclusions: In Tunisian CRKP, colistin resistance was associated with chromosomal alterations, predominantly involving disruption of the MgrB–PhoPQ pathway, in the absence of mcr genes. These mechanisms in both high-risk and emerging sequence types underscore the adaptability of CRKP and the need for surveillance where colistin remains an important therapeutic option. Full article

With the advent of the big data era, traditional storage technologies struggle to meet the demands for long-term, secure, and cost-effective preservation of massive amounts of information. Collinear holographic storage technology has emerged as a strong contender for next-generation optical storage due to its high storage density, rapid parallel transmission, and exceptional reliability. Among various storage materials, phenanthraquinone-doped poly(methyl methacrylate) (PQ/PMMA) photopolymer has garnered significant attention for its negligible photo-induced volume shrinkage, low cost, controllable thickness, and polarization-sensitive holographic response properties. However, the material’s limited photosensitivity, low polarization response, and poor optical uniformity severely constrain its application in high-speed recording and multidimensional multiplexing holographic systems. This paper reviews the primary methods and strategies employed over the past five years to enhance the holographic performance of PQ/PMMA photopolymer materials, based on the microscopic physicochemical mechanisms underlying traditional and polarization holography, including chemical modification, nanoscale doping, mechanical control, etc. Through a systematic review of these research advances, this paper aims to provide theoretical foundations and technical references for developing high-performance PQ/PMMA photopolymer materials suitable for collinear holographic storage. Full article

Weak-grid operation, with a low short-circuit ratio (SCR), degrades voltage and frequency regulation and impacts the power control performance of inverter-based resources, triggering oscillations. This paper proposes a community-scale battery energy storage system (BESS)-supported grid-forming control scheme, where the grid-forming inverter acts a virtual synchronous generator (VSG). A grid-connected BESS-powered VSG model with cascaded voltage-current dual-loop control is developed to assess the impacts of line impedance and P-Q coupling on weak-grid connection and stability. In addition to the conventional VSG, dq-axis decoupling, virtual impedance, and adaptive inertia-damping (J-D) are incorporated and evaluated through multi-scenario MATLAB/Simulink simulations. The results indicate that virtual impedance effectively suppresses coupled oscillations, and the coordinated J-D adaptation yields the most pronounced peak mitigation during edge disturbances (e.g., fault clearance and load shedding). In particular, under a 50% three-phase voltage sag, the coordinated strategy reduces the post-clearance peaks of $v_{pcc,rms}$ and $i_{pcc,rms}$ by approximately 79.9% and 93.5%, respectively, and decreases the intensity of frequency fluctuations by approximately 97.6%. Overall, the proposed community-scale BESS-VSG scheme enhances the dynamic stability of voltage and frequency under weak-grid conditions and provides a practical control framework for engineering-oriented weak-grid support studies. Full article

The increasing penetration of renewable energy has led to the large-scale integration of power electronic devices into the power grid. In weakly connected grids, such devices are connected to the grid via voltage source converters (VSCs) using grid-forming (GFM) control strategies. Ideally, the point of common coupling (PCC) with the grid is treated as a purely inductive circuit. However, in weak grids, the resistance-to-inductance ratio (R/X) cannot be ignored, which leads to the power coupling problem between active power (P) and reactive power (Q). This phenomenon impedes the precise control of P and Q, potentially resulting in steady-state power deviations and even system instability. Traditional power-decoupling methods based on virtual inductance (VI) have inherent limitations and fail to achieve complete decoupling between P and Q. To address this issue, this paper first analyzes the influencing factors of power coupling through an established power coupling model. Comparisons between the output voltage and the degree of power coupling demonstrate that power decoupling can be achieved by compensating the output voltage. Consequently, an improved power-decoupling strategy based on apparent power feedforward (APPFF) is proposed. The proposed APPFF method realizes complete P-Q decoupling, with a steady-state reactive power error of less than 1% of the rated value. Compared with the PI-decoupling method, the reactive power overshoot is reduced by about 24%, and no additional active power overshoot is introduced. Compared with the conventional virtual inductance method that only reduces coupling by up to 35%, APPFF eliminates the power coupling fundamentally while retaining the reactive power–voltage droop characteristics and fast dynamic response. By directly compensating the reference voltage to the ideal value using apparent power as the feedforward variable, the proposed method is essentially different from the existing voltage/angle compensation schemes. The feasibility and effectiveness of the proposed decoupling method are verified under various working conditions, such as different R/X ratios, line resistances and power references, through both Simulink simulations and experimental results. Full article

Background: Schizophrenia in adolescence disrupts neurodevelopment and long-term functioning. While symptom reduction remains a primary treatment goal, quality of life (QoL) represents a critical, patient-centered outcome. Pharmacogenetic variability, particularly in CYP2D6 metabolism of second-generation antipsychotics, may influence tolerability and subjective well-being beyond symptom control. Materials and Methods: Forty-seven adolescents (aged 14–18 years) diagnosed with schizophrenia (DSM-5) were followed in routine clinical care. CYP2D6 genotyping classified patients as normal metabolizers (NM, n = 27) or reduced-function metabolizers (RFM, including intermediate/poor, n = 20). Symptom severity was assessed with PANSS, QoL was assessed with the Pediatric Quality of Life Enjoyment and Satisfaction Questionnaire (PQ-LES-Q), and adverse effects (hyperprolactinemia, extrapyramidal symptoms, sedation, metabolic changes) were monitored. Non-parametric tests and multiple linear regression were applied. Results: At 12 months, RFM patients showed significantly higher PANSS scores, markedly more adverse reactions (95% vs. 48.1%), and lower PQ-LES-Q total and domain scores (all p < 0.0001) compared to NM patients. A regression analysis identified the metabolizer status (β = −0.410, p = 0.001), extrapyramidal symptoms (β = −0.248, p = 0.003), sedation (β = −0.193, p = 0.029), and hyperprolactinemia (β = −0.190, p = 0.012) as independent predictors of a reduced QoL, explaining 84% of the variance. The residual symptom severity was not independently associated. Conclusions: In adolescent schizophrenia, the CYP2D6-reduced metabolizer status is the strongest independent predictor of long-term QoL impairment, associated primarily through a substantially higher burden of treatment-related adverse effects (metabolic, endocrine, neurological, and sedative) rather than through persistence of psychotic symptoms alone. These findings support early pharmacogenetic testing to guide individualized dosing and improve tolerability and patient-reported outcomes. Full article

The intermittent nature of photovoltaic (PV) energy, especially under nonlinear and unbalanced loading situations, has made it more difficult to ensure steady operation as it is increasingly integrated into modern power systems. The Power Quality (PQ) issues cause severe degradation of both system performance and device lifetime. A novel Neural Power Quality Network (NeuPQ-Net) controlled Unified Power Quality Conditioner (UPQC) combined with a Quasi Z-Source Lift (QZSL) converter for PV applications is presented in this research as a novel solution for addressing these issues. The QZSL converter, which is controlled by a Maximum Power Point Tracking (MPPT) algorithm based on Perturb and Observe (P&O), increases the PV source voltage to the necessary DC-link level. A Zebra Optimisation Algorithm tuned PI (ZOA-PI) controller continually adjusts PI gains for quick and accurate regulation, ensuring steady DC-link voltage. Unlike conventional Synchronous Reference Frame (SRF) or Decoupled Double Synchronous Reference Frame (DDSRF)-based reference generation, the proposed NeuPQ-Net operates directly in the abc domain, eliminating Phase-Locked Loop (PLL) dependency and reducing computational complexity. Simulation and hardware prototype validations demonstrate that the proposed system achieves significant improvements in PQ indices, including reduced Total Harmonic Distortion (THD), faster response to transients, and enhanced voltage regulation, while complying with IEEE-519 standards. Full article

Coffea arabica, a popular beverage ingredient, is prized for its rich chemical composition, which has demonstrated significant positive effects in terms of antioxidant, anti-inflammatory, neuroprotective, and metabolic health. In November 2024, fruit rot with a 15% incidence was observed on C. arabica in Menglian city, Yunnan province, China. Symptoms began as irregular black spots that turned necrotic, wrinkled, and cracked. Fungal isolates from lesions showed morphological characteristics consistent with Fusarium coffeibaccae. Morphological data were supplemented with phylogenetic analyses based on three loci (ITS, TEF1-α, RPB2), and sequences were deposited in GenBank as for ITS (PV211189 and PV211190), TEF1-α (PQ867811 and PQ867812), and RPB2 (PV261064 and PV261065). Koch’s postulates were fulfilled on attached fruits. After 17 days at 25 °C with 70% humidity, typical rot symptoms appeared on inoculated fruits, while controls remained symptom-free. This is the first report of C. arabica fruit rot caused by F. coffeibaccae in China. This study aims to identify the aetiological agent of recently observed coffee fruit rot in Yunnan and to characterize F. coffeibaccae. It provides the first baseline data for targeted monitoring and sustainable control of F. coffeibaccae-mediated fruit rot in China’s expanding coffee sector. Full article

The rapid deployment of electric vehicles (EVs) has introduced new challenges to distribution networks, which are mainly related to power quality and grid reliability. Electric vehicle chargers behave as nonlinear loads because they are based on power electronic converters, which generate harmonic currents, cause voltage distortion, increase stress on network components, and might impact the overall power quality of distribution networks. In this study, power quality (PQ) measurements and harmonic characteristics were investigated for five electric vehicle models, namely the BYD Song Plus, Volkswagen ID6, Neta U, Nissan LEAF 2016, and Tesla Model 3. Measurements were carried out for different power levels—slow AC, low-power and fast AC, high-power charging modes—to evaluate the PQ characteristics and harmonic behavior of EVs. Fast charging power levels for most vehicles ranged between 5 and 11 kW, while slow charging ranged between 2.7 and 3.6 kW. It is found that harmonic characteristics, total harmonic current distortion (THD_I), and harmonic distribution depend on the EV type and the charging mode. This study found that THD_I varies between 1.5% and 10.72% for the tested EVs. Comparison with IEC power quality standards indicates that the impact of electric vehicle charging on voltage quality is limited, while current harmonic distortion varies significantly among vehicle models. Harmonic analysis reveals that the third and fifth orders dominate across most of the tested EVs, while the transition from slow to fast charging power level generally reduces low-order harmonics in most models, with vehicle-specific redistribution patterns that reflect converter topology and control strategy. The results also show that some EV chargers draw reactive power and operate with a lagging power factor, whereas other vehicles inject reactive power and operate under leading power factor conditions. Full article

Morphine is widely used as an analgesic in vertebrates, yet its cardiorespiratory safety and effective therapeutic range remain poorly explored in fish. This study investigated the dose-dependent effects of morphine on cardiac and respiratory parameters of juvenile tambaqui (Colossoma macropomum). Juveniles (25.95 ± 4.08 g) were randomly assigned to control, sham (0.9% saline) or morphine groups (24, 28, 32, 36 and 40 mg kg⁻¹, i.p.). Electrocardiogram (ECG) recordings were used to assess heart rate (HR), PQ, RR and QT intervals, and QRS amplitude, while opercular beat rate (OBR) and opercular beat intensity (OBI) were measured to evaluate respiratory responses. Morphine induced a significant dose-dependent bradycardia and QT prolongation, without affecting QRS amplitude or conduction integrity. Respiratory frequency and intensity also decreased with increasing doses, with responses plateauing above 32 mg kg⁻¹. The EC₅₀ for HR reduction was 27.18 mg kg⁻¹, aligning with a safe therapeutic range of 24–32 mg kg⁻¹. By establishing this dose–response dynamic, the study provides the first characterization of a physiologically safe therapeutic window of morphine in tambaqui and highlights its safety profile for cardiorespiratory parameters. Moreover, the present results demonstrate that the opioid system of juvenile tambaqui is functionally developed, providing a physiological basis for future studies on nociception and analgesic efficacy, with relevance to welfare-oriented practices in aquaculture. Full article

Quorum-sensing (QS) systems play a crucial role in regulating virulence, biofilm formation, and antibiotic resistance in clinically relevant microbes. This review explores the potential of QS systems as targets for developing novel plant-based therapeutic strategies using bioinformatics, aimed at combating highly pathogenic bacteria: uropathogenic Escherichia coli (UPEC) and Pseudomonas aeruginosa. We examine the key components and molecular pathways of QS systems in these microbes, including autoinducer synthases, receptors, and regulatory proteins. In UPEC, we discuss the LuxS-dependent autoinducer (AI)-2 system, while for P. aeruginosa, we analyze the more complex interconnected Las, Rhl, and PQS circuits. We highlight how these systems control the expression of virulence factors and contribute to biofilm formation, emphasizing their importance in pathogenesis. Furthermore, we explore bioinformatics approaches for identifying and characterizing QS components, i.e., by predicting protein structures and interactions. The potential of in silico screening for QS inhibitors is also discussed, along with challenges and opportunities in targeting QS systems for therapeutic interventions. By integrating microbiological, molecular, and computational perspectives, this review aims to provide insights into the application of bioinformatics in understanding and targeting QS systems in these clinically significant pathogens. The goal is to facilitate the development of novel anti-virulence approaches in search of novel antibiotics that could complement or replace traditional antibiotic treatments, addressing the growing concern of antimicrobial resistance in these clinically relevant microbes. Full article

Biofuel cells (BFCs) generate electricity by converting chemical energy into electrical energy using biological systems. Saccharomyces cerevisiae (yeast) is an attractive biocatalyst for BFCs due to its robustness, low cost, and metabolic versatility; however, electron transfer from the intracellular reactions to the electrode is limited by the cell membrane. Nystatin is an antifungal antibiotic that increases the permeability of fungal membranes. We hypothesized that sub-lethal nystatin treatment could enhance mediator-assisted electron transfer without compromising cell viability. In this work, yeast was treated with nystatin during cultivation at concentrations of up to 6 µg/mL and combined with a dual-mediator system consisting of a lipophilic mediator (9,10-phenanthrenequinone, PQ) and a hydrophilic mediator (potassium ferricyanide). Scanning electrochemical microscopy revealed that the dual-mediator system increased local current responses by approximately fivefold compared to a single mediator (from ~11 pA to ~59 pA), and that nystatin-treated yeast exhibited higher local electrochemical activity than untreated yeast (maximum currents of ~0.476 nA versus ~0.303 nA). Microbial fuel cell measurements showed that nystatin treatment increased the maximum power density from approximately 0.58 mW/m² to approximately 0.62 mW/m² under identical conditions. Nystatin concentrations between 4 and 5 µg/mL maintain yeast viability at near-control levels, while higher concentrations cause a decrease in viability. These results demonstrate that controlled, sub-lethal membrane permeabilization combined with a dual-mediator strategy can enhance electron transfer in yeast-based biofuel cells. Full article