Search Results (1,815)

Background: Accurate brain tumor segmentation from Magnetic Resonance Imaging (MRI) depends on the fusion of multiple complementary modalities. However, clinical practice often faces incomplete modality sets due to acquisition failures, patient contraindications, or protocol variations. Current methods either treat each modality feature extractor in isolation or depend on computationally expensive teacher networks for cross-modal knowledge transfer. Objective: This paper presents Hierarchical Adaptive Group Self-Support Learning with Boundary-Aware Calibration (HAGSS), a framework that overcomes three key limitations of existing group self-support methods: static group formation that ignores temporal prediction quality, uniform treatment of boundary and interior voxels, and distribution mismatch across heterogeneous modality logits. Methods: We propose a hierarchical adaptive group formation mechanism that reassigns group leader roles at each epoch based on voxel-level prediction confidence scores instead of fixed sensitivity priors. We also introduce a boundary-aware calibration module that applies spatially varied distillation weights with greater emphasis on tumor boundary regions. In addition, we design a cross-scale consistency regularization term that enforces agreement between multi-resolution predictions to stabilize the self-support target. Results: Experiments on BraTS2020, BraTS2018, and BraTS2021 datasets show that HAGSS achieves consistent improvements over state-of-the-art baselines. The average Dice gains across the whole tumor, tumor core, and enhancing tumor regions reach 1.30% on BraTS2020 and 1.61% on BraTS2021 compared to existing methods. All improvements are statistically significant ($p<0.05$). Conclusions: HAGSS operates exclusively during training, adds no parameters or inference cost, and can be applied as a plug-in module to any multi-encoder incomplete multi-modal segmentation architecture. Code is publicly available at GitHub. Full article

Crustal magnetic fields exert a fundamental control on the structure and dynamics of the Martian ionosphere. In this study, we use in situ ion composition measurements from the MAVEN Neutral Gas and Ion Mass Spectrometer (NGIMS) to investigate how crustal magnetic fields modulated the Martian upper atmosphere during the June 2018 global dust storm. By restricting the analysis to a narrow range of solar zenith angles and altitudes, we isolate magnetic effects from variations driven by solar illumination and vertical structure. We find that the densities of O₂⁺, O⁺, and CO₂⁺ differ systematically between regions of strong and weak crustal magnetic fields, with strong-field regions exhibiting reduced variability consistent with magnetic confinement. Importantly, a substantial fraction of observations located outside traditional geographic masks display ion composition signatures that closely resemble those observed in strong-field regions. Spatial analysis shows that these “strong-like” undetermined observations preferentially occur near known crustal magnetic anomalies, indicating that magnetic influence extends beyond fixed geographic boundaries. These results demonstrate that ion composition provides a sensitive diagnostic of magnetic topology at Mars and reveal the importance of magnetic connectivity in regulating ionospheric structure under extreme atmospheric conditions. Our findings suggest that static geographic classifications may underestimate the true spatial reach of crustal magnetic control during periods of enhanced atmospheric disturbance. Full article

This paper investigates abnormal secondary voltage drops in dry-type transformers operating in isolated offshore power systems. While conventional analyses primarily attribute voltage deviations to load conditions and transformer impedance, this study shows that noticeable voltage drops can also occur under no-load conditions due to the combined effects of voltage unbalance, harmonic distortion, and residual magnetic flux. A comprehensive approach integrating on-site measurements, PSCAD simulations, and laboratory experiments is employed to systematically analyze this phenomenon. The results indicate a coupled electromagnetic effect in which source-side voltage imperfections induce asymmetric core flux distribution, which is associated with reduced secondary voltage. In addition, a relationship between synchronous generator winding pitch and harmonic voltage distortion is observed, suggesting its influence on power quality in isolated grids. Simulation results show that the interaction of these factors can lead to a secondary voltage drop of approximately 4–6 V under no-load conditions, even in the absence of transformer defects. Finally, mitigation strategies based on voltage balancing and harmonic reduction are experimentally validated, restoring the secondary voltage to 1.002 pu. These findings provide practical insights for improving voltage stability and power quality in offshore and other isolated power systems. Full article

Sparganium stoloniferum tubers (SL), known medicinally as Sparganii Rhizoma, are commonly considered superior at the winter-harvest stage, when they show the traditional quality traits of heavy weight and firm texture. However, the developmental basis of this quality phenotype remains insufficiently understood. This study aimed to determine how tissue organization, cell-wall architecture, starch deposition, and related transcriptional patterns are associated with winter-harvest quality in SL. By comparing SL at different developmental stages, we found that maturation was accompanied by reduced moisture content, increased tuber density, higher parenchyma cell density, progressive cell-wall thickening, and marked starch accumulation. Laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) observations further revealed thickened multilamellar cell walls and abundant clustered or compound-like starch bodies in mature SL. Starch isolated from mature SL displayed an A-type crystalline pattern, short-range order, and high gelatinization and pasting temperatures, indicating an ordered and thermally stable starch matrix. Cell-wall Fourier-transform infrared spectroscopy (FTIR) and solid-state nuclear magnetic resonance (NMR) analyses showed a predominantly polysaccharide-rich framework with subtle maturation-associated changes in aromatic- and methoxy-associated wall signals. Transcript-guided pathway analysis, supported by reverse transcription quantitative polymerase chain reaction (RT–qPCR)validation, suggested developmental shifts in carbohydrate metabolism, lipid-related metabolism, and gibberellin-associated transcriptional patterns. Together, these findings indicate that winter-harvest quality in SL is associated with coordinated tissue consolidation, cell-wall maturation, starch deposition, and transcriptional reprogramming, providing a structural and molecular framework for understanding the traditional firm-texture trait of S. stoloniferum. Full article

Magnetorheological elastomers (MREs) have recently attracted significant attention for the development of adaptive vibration isolators and absorbers. Their ability to tune mechanical properties in response to external excitations makes them promising candidates for semi-active control applications. In this study, the Generalized Maxwell model with three Maxwell branches is employed to predict variations in storage and loss moduli of isotropic MREs operating in shear mode under varying excitation frequencies and magnetic flux densities. A practical semi-active MRE-based seat vibration isolator is proposed, and a multidisciplinary design optimization problem is subsequently formulated to determine the optimal geometrical parameters of the isolator. The objective is to maximize the frequency bandwidth while satisfying constraints on weight, material magnetic saturation, and total volume. The optimization results demonstrate that the proposed adaptive isolator can achieve a significant relative increase in its natural frequency by adjusting the applied magnetic flux density, while maintaining a practical total mass. A post-optimality analysis is also conducted to investigate the influence of the upper bound on the isolator’s mass. The findings reveal a nonlinear relationship between the optimal frequency ratio and the total mass of the isolator. Finally, closed-loop control strategies based on on–off skyhook and PID control are implemented and compared to evaluate the capability of the proposed adaptive isolator to mitigate vibration and shock under varying disturbances. Full article

Conventional memory machines often suffer from magnetic interference between high-coercive-force (HCF) and low-coercive-force (LCF) permanent magnets, which unintentionally alters the magnetization state and limits overload capability. To address this challenge, this paper proposes a novel axial parallel memory machine (DCB-AXMM) featuring a DC-bias-controlled variable-flux capability. Instead of a conventional structure, the proposed machine employs an axially segmented topology to spatially isolate the excitation sources, effectively shielding the LCF PMs from HCF PM interference and armature reaction. Furthermore, integrated windings are utilized to perform both armature excitation and pulse magnetization, thereby enhancing the overall space utilization. The flux-regulating mechanism is theoretically elucidated using a piecewise linear hysteresis model. To maximize electromagnetic performance, a two-step optimization framework based on a genetic algorithm (GA) is implemented. Comprehensive non-linear finite element analysis (FEA) is conducted to validate the proposed design. Quantitative results demonstrate that the DCB-AXMM achieves a wide flux regulation range, characterized by a 21.8% average torque reduction from 2.2 Nm at full magnetization to 1.72 Nm at zero magnetization, while maintaining a robust 1.5-times overload capability. These measurable outcomes confirm the topology’s effectiveness and reliability for high-performance variable-flux applications. Full article

Background/Objectives: Achillea millefolium is a well-known plant used in traditional medicine for the treatment of inflammation, gastrointestinal disorders, respiratory diseases, hypertension, and diabetes, among others. These effects are attributed to the metabolite content of flavonoids and terpenes such as achillin (1) and leucodin (2). Thus, the current investigation aims to standardize the extracts from A. millefollium based on the presence of 1 and 2 and relate them to their relaxant effect in ex vivo assays. Methods: A validated High-Performance Liquid Chromatography (HPLC) method was used to determine the concentration of the main compounds, employing standard molecules previously isolated from the same species and characterized by nuclear magnetic resonance (NMR) and X-ray diffraction. Also, the relaxant effects of both compounds and their combinations were assayed on aortic and tracheal rat rings in an organ bath. Results: Compounds (1) and (2) are the main compounds in hexane, dichloromethane, and hydroalcoholic extracts, present in different proportions. The relaxant effects in ex vivo models of the aorta and trachea showed that the sesquiterpene lactones achillin (1) [Trachea, maximum effect (Emax): 67.67 ± 5.01%, medium effective concentration (EC50): 304.44 ± 2.61 µM; Aorta: Emax: 63.94 ± 6.28%, EC50: 225.73 ± 4.49 µM)] and leucodin (2) (Trachea: Emax: 76.71 ± 4.73%, EC50: 266.40 ± 2.05 µM; Aorta, Emax: 72.96 ± 1.73%, EC50: 163.29 ± 2.99 µM) are responsible for the relaxant effects shown by the extracts. The observed effect is proportional to the concentration of these molecules, with hexane extracts being more active. Additionally, we demonstrate the safety of molecules 1 and 2 through toxicological studies recommended by the OECD. Conclusions: The isolated compounds achillin and leucodin are the primary constituents in the flowers of A. millefolium, with higher concentrations found in hexane extracts, particularly of achillin, which shows a correlation of 2.33 with respect to leucodin. This correlation is closely related to their relaxant effect, as these compounds are the main contributors to the relaxant response in the trachea and aorta, being more effective when used together. Full article

Background: South Korea continues to report a considerable burden of drug-resistant tuberculosis (TB). Bedaquiline-containing regimens are recommended for multidrug-resistant pulmonary TB, but evidence regarding the optimal treatment for extrapulmonary manifestations such as spinal TB remains limited. Case presentation: Herein, we report two cases of drug-resistant tuberculous spondylitis that were successfully managed using bedaquiline-containing regimens. Case 1 involved a 67-year-old man who was receiving chemotherapy for lymphoma and had a history of spinal TB treated 20 years earlier. The patient presented with dysphagia and upper limb weakness. Cervical magnetic resonance imaging revealed C4–5 spondylitis with an epidural abscess. He underwent surgical treatment, and Mycobacterium tuberculosis resistant to rifampin was isolated from cultured intraoperatively obtained tissue specimens. The patient received an antibiotic regimen consisting of bedaquiline, levofloxacin, linezolid, cycloserine, and clofazimine. Clinical and radiological improvements were achieved after 12 months of this treatment; bedaquiline was included in the regimen for the first 6 months, while the other agents were continued for the entire course. Case 2 involved a 71-year-old man with T12–L2 spondylitis and a left psoas abscess. Tissue culture confirmed Mycobacterium tuberculosis resistant to isoniazid, rifampin, and ethambutol. The patient was started on the same bedaquiline-containing regimen. Clinical and radiological improvements were observed after 18 months of this therapy, including 6 months of bedaquiline. Conclusions: Our clinical experiences suggest that bedaquiline-containing regimens represent a feasible and effective therapeutic option for drug-resistant tuberculous spondylitis. Larger studies are warranted to establish the optimal management strategies for extrapulmonary drug-resistant TB infections. Full article

Objectives: Autism spectrum disorder (ASD) is increasingly conceptualized as a neurodevelopmental condition with prenatal origins. Advances in fetal magnetic resonance imaging (MRI), including high-resolution structural imaging and resting-state functional connectivity analysis, now enable in vivo characterization of the developing human brain before birth. This review examines whether fetal MRI biomarkers are associated with later ASD diagnosis or autistic traits. Methods: We conducted a PRISMA-informed narrative review of human studies identified through MEDLINE, EMBASE, SCOPUS, and Web of Science. Eligible studies included original human investigations using fetal MRI to assess brain structure and/or function, with postnatal ASD diagnosis or standardized autistic-trait outcomes. Results: Eight eligible studies provide converging evidence that neurodevelopmental divergence associated with ASD may be detectable in utero. Structural analyses consistently report prenatal volumetric alterations, particularly enlargement of the insular cortex between the second and third trimesters. Additional findings of regional overgrowth and hemispheric asymmetries suggest distributed deviations in cortical maturation. Functional fetal MRI studies further demonstrate atypical large-scale network organization prior to birth. Altered connectivity within cingulate, prefrontal, temporal, and cerebellar circuits has been prospectively associated with later autistic traits, indicating that network-level integration may diverge before behavioral symptoms emerge. Evidence from high-risk conditions, including isolated ventriculomegaly and tuberous sclerosis complex, reinforces the association between prenatal structural abnormalities and increased ASD risk. Conclusions: Current evidence suggests that structural and functional brain alterations identifiable by fetal MRI may precede the clinical manifestation of ASD. These findings support a model of ASD as a condition potentially rooted in prenatal neurodevelopmental divergence. However, larger, standardized, multicenter studies are required before fetal MRI biomarkers can be translated into predictive or clinical applications. Full article

In this study, a homogeneous polysaccharide, designated as PFP-80, was isolated from the dried root of Polygonatum filipes using enzymatic extraction combined with graded ethanol precipitation. Structural characterization suggested that PFP-80 was a fructan polysaccharide with a molecular weight of 4.06 kDa. The analysis with gas chromatograph–mass spectrometer (GC–MS) and nuclear magnetic resonance (NMR) further confirmed that PFP-80 consisted of →1)-β-D-Fruf-(2→ and →1,6)-β-D-Fruf-(2→ linkages, with branching occurring at the O-6 position. After 48 h of fermentation, the pH was decreased while SCFAs were increased significantly due to the utilization of PFP-80. Furthermore, PFP-80 was found to modulate the gut microbiota by enhancing microbial abundance and diversity, and by impeding the growth of deleterious pathogens such as Ruminococcus gnavus. In summary, the present results provide a scientific basis for the subsequent development of PFP-derived functional food products. Full article

This study investigates the enhancement of hydrogen production efficiency in water electrolysis through the application of external magnetic fields. A series of controlled experiments were conducted using four distinct electrode materials—stainless steel (SS), low-carbon steel (LCS), titanium (Ti), and platinum-plated titanium (Ti/Pt)—to identify the optimal configuration for maximizing gas output. The research evaluated the influence of electrolyte concentration (KOH), current density, and magnetic field intensity ranging from 0 to 1800 G. Our findings indicate that the application of a 200 G magnetic field leads to a notable 6% increase in the rate of gas production compared to non-magnetized conditions. Specifically, a magnetic field oriented parallel to the electrode plates outperformed a perpendicular orientation by approximately 5%, a phenomenon attributed to the Lorentz force facilitating ionic mass transfer and gas bubble detachment. Furthermore, the integration of ion-exchange and proton-exchange membranes (MC-3470 and N-117) effectively isolated the anodic and cathodic products, elevating hydrogen purity from 67.4% to approaching 100% without compromising electrolysis efficiency. These results demonstrate that the strategic coupling of moderate magnetic fields with optimized electrode configurations provides a promising pathway for improving the efficiency and cleanliness of hydrogen production, which is essential for its role as a sustainable energy carrier. Full article

The genus Trichinella comprises zoonotic nematodes infecting a wide range of carnivorous and omnivorous animals, including humans. Infection occurs through the consumption of raw or undercooked meat containing viable Trichinella larvae. Among the species within this genus, Trichinella spiralis is considered one of the most epidemiologically important due to its high reproductive capacity and its frequent association with infections in domestic animals and humans. In this study, muscle samples from 18 invasive American minks (Neovison vison) were examined for Trichinella larvae using the magnetic stirrer method. Species identification was performed via multiplex polymerase chain reaction (PCR), while the internal transcribed spacer 1 (ITS1) region was amplified to evaluate the intraspecific genetic variability. Trichinella larvae were detected in one of the 18 (5.6%) animals investigated, and all isolates were identified as T. spiralis. Ten ITS1 sequences obtained from individual larvae were 100% identical. Network and principal coordinate analyses revealed that the sequences clustered by geographic origin rather than host species and were more related to isolates from domestic pigs than to wildlife animals. These findings provide the first evidence of T. spiralis in American minks in Baltic and Scandinavian countries and contribute to a better understanding of the epidemiology of trichinellosis in the region. Full article

Background and Purpose: Complete angiographic reperfusion (TICI 3) is considered the optimal procedural endpoint of mechanical thrombectomy (MT) in acute ischemic stroke. However, new diffusion-weighted imaging (DWI) lesions are frequently observed despite apparent angiographic success. We aimed to investigate the incidence, morphological patterns, and clinical relevance of these lesions in a strictly defined TICI 3 cohort. Methods: In this retrospective single-center study, 89 patients with anterior circulation large-vessel occlusion (LVO) who achieved true TICI 3 were analyzed. Baseline and follow-up Magnetic Resonance Imaging (MRI) within 48 h were systematically compared using paired diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps to identify new lesions. Lesions were classified according to morphology and distribution. Stroke etiology was assessed using TOAST criteria. Functional outcomes were evaluated using the 90-day modified Rankin Scale (mRS) with the Rankin Focused Assessment. Results: New DWI lesions were detected in 28 of 89 patients (31.5%). The predominant pattern was millimetric cortical foci (85.7%), most frequently ipsilateral to the recanalized vessel (78.6%), with fewer contralateral (14.3%) and bilateral (7.1%) lesions. Territorial infarcts and isolated basal ganglia infarcts were each identified in 14.3% of patients, with some overlap between categories. No significant differences were observed between patients with and without new lesions regarding baseline characteristics or procedural metrics (all p > 0.05). Importantly, the presence of new DWI lesions was not associated with 90-day functional outcome (p = 0.930) or survival (p = 0.613). Conclusions: New DWI lesions are common even after complete angiographic reperfusion, highlighting a persistent dissociation between macrovascular success and tissue-level integrity. Although predominantly small and clinically silent in the short term, these findings underscore the limitations of angiographic endpoints alone and support the need for strategies targeting microvascular protection and prevention of distal embolization. Full article

The torque ripples of robotic permanent magnet synchronous motors (PMSMs) degrade motion smoothness and positioning accuracy of the system, while inevitable load transients in robotic tasks further complicate torque ripple attenuation. To address this issue, this paper develops an event-triggered torque ripple attenuation method that explicitly distinguishes torque ripple from dynamic load transients. First, a sliding-mode torque observer is constructed to obtain real-time torque information, whose stability is rigorously analyzed using a Lyapunov function. Second, frequency-selective torque ripple extraction schemes are proposed to accurately isolate steady-state high-frequency torque ripple from the estimated torque signal. In particular, two specially designed filtering structures are developed and compared, one of which is selected to preserve ripple-related frequency content during test, ensuring robust and accurate ripple identification under varying operating conditions in robotics. Third, a torque-ripple-regulation-based compensation strategy is used within a vector-controlled PMSM drive, in which the extracted torque ripple is processed by a dedicated ripple regulator to generate voltage compensation signals. This strategy achieves effective steady-state torque ripple attenuation with low implementation complexity, while avoiding performance degradation during dynamic load transients. Finally, experimental results are provided to validate the effectiveness of the proposed methods. Full article

Traditional cardiovascular assessment has historically focused on the isolated evaluation of either atrial or ventricular structure and function. However, the left atrioventricular coupling index (LACI) represents a paradigm shift by moving beyond single-chamber metrics to quantify the dynamic interaction between the left atrium and left ventricle. Defined as the ratio of left atrial end-diastolic volume to left ventricular end-diastolic volume, LACI integrates structural and functional aspects of cardiac performance. This comprehensive review examines the physiological basis of how the left atrium and ventricle operate as an integrated hemodynamic unit. We detail current measurement methodologies, including two- and three-dimensional echocardiography, cardiac computed tomography, and cardiac magnetic resonance imaging, which serves as the reference standard. Furthermore, the review explores the pathophysiological mechanisms driving atrioventricular uncoupling, specifically mechanical dysfunction, electromechanical desynchrony, and hemodynamic alterations. Extensive clinical evidence demonstrates LACI’s robust independent prognostic value across diverse cardiovascular conditions, such as heart failure, myocardial infarction, cardiomyopathies, and atrial fibrillation. Observational data suggest that LACI provides a promising prognostic value beyond established risk assessment tools by combining the assessment of both chambers’ interdependence. Finally, we outline future directions for clinical translation, highlighting the necessity for standardized measurement protocols, the integration of artificial intelligence, and the potential of LACI as a target for personalized therapeutic strategies. Full article