Search Results (104)

Radiofrequency ablation (RFA) is a foundational interventional technology in pain management. Despite the diversity of available systems, conventional thermal, internally cooled, bipolar, and pulsed radiofrequency (PRF) all share one biophysical mechanism: high-frequency alternating current (AC) drives tissue ions to oscillate, generating frictional heat within the tissue surrounding the electrode. This localized heating produces predictable patterns of coagulative necrosis shaped by tissue electrical conductivity, electrode geometry, power delivery, and perfusion-related heat dissipation. Classical and contemporary bioheat models, including the Pennes bioheat equation, describe how these variables determine lesion size and morphology. Advances in device engineering have reshaped lesion characteristics through internally cooled probes, bipolar strip-lesioning systems, and pulsed platforms that modulate neural activity while preserving structural integrity. These innovations broaden therapeutic options by enabling targeting of anatomically variable structures, such as the sacral lateral branches, and intraosseous targets, including the basivertebral nerve (BVN). Emerging technologies—high-voltage PRF, hybrid pulsed–thermal systems, and electroporation-based pulsed-field ablation—reflect a growing emphasis on tissue selectivity, energy efficiency, and safety. This narrative review traces the historical development of radiofrequency neurotomy, examines the biophysical principles governing lesion formation (including the Pennes bioheat equation and the roles of current density, impedance, and perfusion), and details the engineering distinctions among modalities. Clinical applications across spinal, joint, and peripheral nerve targets are presented to illustrate how these physical and engineering differences translate into procedural decision-making, and emerging modalities such as high-intensity focused ultrasound (HIFU) and pulsed-field ablation are discussed in the context of the biophysical principles they extend or depart from. Full article

Pulsed Field Ablation (PFA) is an emerging technique for the treatment of cardiac arrhythmias based on the irreversible electroporation of cardiomyocytes. It is rapidly replacing conventional thermal ablation owing to its tissue selectivity. However, its widespread clinical adoption has also highlighted several procedure-related complications. Although PFA is generally regarded as tissue-selective, increasing evidence indicates that exposing circulating blood to intense electric fields may induce red blood cell (RBC) damage and hemolysis. In this work, we develop a physics-based mathematical model to predict the extent of hemolysis during PFA procedures. The model combines a simplified representation of the electric field generated by a bipolar PFA catheter with experimentally derived hemolysis–response relationships, allowing the volume of damaged blood and free hemoglobin (fHb) release to be predicted as functions of pulse amplitude, pulse number, and device geometry. The proposed framework is consistent with both classical electroporation theory and recent clinical observations reporting a dose-dependent increase in hemolysis following PFA. The results provide a mechanistic interpretation of blood damage during PFA. Despite several simplifying assumptions, the proposed framework yields a quantitative tool for assessing hemolytic risk and may support the optimization of future PFA protocols. Full article

Water dissociation (WD) at the internal junction of bipolar membranes (BPMs) is the key process enabling acid/base generation under reverse bias, yet the physical origin of its strong enhancement remains debated. In our previous work, we proposed a power-dissipation model in which WD is enhanced by an intense electric field through local power dissipation by autoprotolysis ions. Here, we experimentally validate this model using three commercial BPMs under acid/base and neutral salt conditions and extend it to high current density by incorporating finite water supply to the BPM junction. Under acid/base conditions, two BPMs showed strong field-dominated quadratic behavior, while a catalyst-containing BPM displayed a predominantly linear response, indicating that heterogeneous interfacial catalysis can mask the purely field-driven signature. In neutral $N{a}_{2}S{O}_4$, all three BPMs exhibited excellent quadratic fits, confirming that the predicted $J_{WD}\propto U_j^2$ behavior is robust. The fitted prefactor varied with membrane type and electrolyte configuration, reflecting differences in hydration, junction thickness, transport behavior, and catalysis effect. The model was extended at higher current density to include finite diffusive water supply to the junction. The resulting saturation law links the intrinsic quadratic WD current $J_{\mathrm{W}\mathrm{D}}$ to a water-transport-limited current $J_{\mathrm{l}\mathrm{i}\mathrm{m},2}$, and predicts an inflection point at $J_{\mathrm{W}\mathrm{D},\mathrm{i}\mathrm{n}\mathrm{f}} = 0.25 J_{\mathrm{l}\mathrm{i}\mathrm{m},2}$. Full article

Pulsed Electric Fields (PEF) offer significant potential to enhance energy efficiency and reduce reliance on SO₂ and other chemical preservatives, aligning with current sustainability and health demands. This work evaluates PEF industrial viability for wine stabilisation through a multidisciplinary pilot-scale approach (108 L/h). A sulfur-free comparative trial evaluated four sequential bipolar PEF treatments (20–23 kV/cm; 19–34 kJ/kg) against stabilisation with a commercial chitosan–glucan complex. PEF caused significant effects on microbial kinetics: B. bruxellensis was successfully maintained below the detection limit and lactic acid bacteria (LAB) were undetected by the end of the trial. Standard oenological parameters showed no relevant changes, except for lactic acid dynamics, corroborating LAB knockdown. Regarding metal ion migration into the food matrix, Fe, Ni, and Cr were assessed. No significant variations were found for Fe and Ni compared to the control group; all elements presented residual concentrations compatible with international regulatory guidelines. Sensory analysis revealed that PEF-treated wines exhibited lower perceived bitterness and higher colour intensity, driven by B. bruxellensis proliferation in control wines. In total, 75% of panellists preferred PEF wines. OPEX analysis demonstrates industrial competitiveness for medium-to-large scale, reducing consumable costs over 10-fold (0.6064 vs. 6.50 €/hL), excluding initial CAPEX. These findings validate multi-stage, pilot-scale PEF as a competitive and electrochemically safe technology to transition toward sustainable reduced-SO₂ or SO₂-free winemaking. Full article

Background and Clinical Significance: This report investigates the complex intersection of macrostructural neuroprotection and cortical hyperexcitability during long-acting atypical antipsychotic maintenance. We present a novel clinical case demonstrating an apparent absence of detectable cerebellar vermis atrophy progression during long-acting injectable (LAI) aripiprazole maintenance, which temporally coincided with the emergence of a potential epileptogenic risk in an adolescent with bipolar disorder (BD) and cannabis use disorder. Beyond motor precision, the vermis modulates emotional-cognitive networks; deficits in these circuits impair impulse control, frequently driving comorbid substance use in youth. Case Presentation: A 16-year-old female with BD and cannabis use disorder presented with pronounced cerebellar and vermis atrophy on brain CT during an acute behavioral crisis. Following diagnostic reformulation, maintenance therapy was initiated via off-label monthly LAI aripiprazole (400 mg) alongside lithium. At 9-month follow-up, psychiatric relapses and cannabis use remitted completely. Repeat CT suggested macrostructural stability with zero apparent atrophy progression. However, during the 9th month, she abruptly developed daily generalized myoclonus. An awake electroencephalogram (EEG) revealed intense cortical hyperexcitability, documenting frequent interictal and ictal epileptiform discharges with generalized 3–4 Hz spike-wave complexes synchronized with the clinical myoclonus. Introduction of levetiracetam (500 mg BID) and cessation of adjunct methylphenidate led to complete clinical and neurophysiological remission. Conclusions: LAI aripiprazole may favorably influence the macrostructural trajectory of the cerebellum/vermis in adolescent BD, suggesting volume stabilization. However, clinicians must monitor for a drug-induced lowering of the seizure threshold, where macrostructural volume preservation coexists with microstructural electrical destabilization. Full article

Silk fibroin (SF) is a promising bio-compatible material for transient and bio-integrated memory devices; however, its relatively high leakage current and limited resistance state stability remain critical issues. In this study, Ag/SF–TiO₂/Pt bio-memristors were fabricated using SF–TiO₂ composite films with TiO₂ nanoparticle concentrations of 0, 0.25, 0.5, and 1.0 wt%. SEM analysis showed that TiO₂ incorporation increased particle aggregation while maintaining continuous film morphology. Optical analyses revealed that TiO₂ nanoparticles reduced the apparent optical gap, enhanced sub-bandgap absorption, and suppressed photoluminescence intensity, indicating the formation of defect- and trap-related states. Electrical measurements demonstrated that TiO₂ incorporation effectively reduced leakage current and stabilized the high-resistance state. The devices exhibited stable bipolar resistive switching within ±1 V, with enhanced I_on/I_off ratios of approximately 10⁴–10⁵ after TiO₂ addition. Endurance and retention measurements confirmed reliable switching over 100 cycles and stable resistance states up to 10⁴ s. Capacitance analysis further revealed resistance state-dependent charge storage behavior, with higher capacitance in the low-resistance state due to conductive filament formation and TiO₂-assisted interfacial polarization. These results indicate that TiO₂ nanoparticles effectively modulate charge trapping, leakage suppression, and memory stability in SF-based bio-memristors. Full article

An experimental morphology-based information extraction methodology is presented for locating reinforcing bars and estimating their effective ultrasonic scattering diameters in reinforced concrete (RC) members using ultrasonic pitch–catch (UPC) non-destructive testing combined with synthetic aperture focusing technique (SAFT) reconstruction. Reinforced concrete slab specimens with known reinforcement layouts were constructed and tested using a commercial ultrasonic device equipped with dry point contact shear wave transducers in a pitch–catch configuration. The collected ultrasonic data were post-processed using an in-house software package to reconstruct two-dimensional (2D) SAFT images of the specimens. In the reconstructed images, embedded rebars consistently produced characteristic bipolar scattering responses composed of dominant trough–crest waveform pairs. Based on these repeatable scattering response features, an empirical morphology-based procedure was developed in which rebar depth was estimated from the midpoint of the dominant trough–crest pair, while the effective ultrasonic scattering diameter was characterized using their vertical separation. The experimental results obtained from twelve reinforced concrete slab specimens demonstrated reliable depth estimation and a strong monotonic relationship between reconstructed scattering response width and nominal rebar diameter under the investigated testing conditions. Regression analysis indicated that larger rebars generally produced broader reconstructed bipolar scattering responses due to cylindrical wave interaction, diffraction, interference, finite transducer aperture effects, and SAFT reconstruction characteristics. The proposed methodology does not attempt to reconstruct the exact physical boundary of the reinforcement or solve the full elastodynamic inverse problem. Instead, the proposed methodology provides a practical and computationally efficient morphology-based information extraction framework that transforms reconstructed ultrasonic scattering responses into quantitative morphological descriptors for embedded reinforcement characterization. By extracting repeatable scattering response features from SAFT-reconstructed images and establishing an empirical mapping between these descriptors and reinforcement characteristics, the proposed approach enables the quantitative interpretation of ultrasonic images without requiring computationally intensive full waveform inversion. Full article

In this work, based on a half-bridge circuit and pulse transformer, a miniaturized and low-cost microsecond high-voltage pulsed power supply for the atmospheric pressure plasma jet (APPJ) is designed. Because of the low bus voltage of the half-bridge circuit, low-voltage switches can be chosen by the power supply. The characteristics of the output high voltage of the power supply are studied. The experimental results show that uni-polar and bi-polar pulses can be generated by the power supply. The high-voltage pulses have good consistency at different frequencies, and the amplitude of the high-voltage pulse varies approximately linearly with the bus voltage. A needle-ring plasma jet device was driven by the uni-polar pulse of this supply, and the single discharge current pulse can be obtained at the rising edge and falling edge of the high-voltage pulse, respectively. The effects of voltage pulse on APPJ and the characteristics of jet are also investigated. The results show that the plasma jet is only formed at the rising edge of the voltage pulse. The jet length is almost unaffected by the pulse frequency, whereas the normalized intensity of most species increases with frequency linearly. Full article

Background: White matter hyperintensities (WMHs) have been implicated in late-onset psychiatric disorders, but their contribution to this clinical phenotype remains insufficiently understood. Methods: We conducted a cross-sectional transdiagnostic study of 90 consecutively admitted acute patients with schizophrenia, bipolar disorder (BD), and major depressive disorder (MDD) meeting the predefined inclusion criteria. Patients with a late onset were compared to earlier onset (EO) psychiatric patients. Late onset was defined as the median age of the disorder onset of the sample (≥40 years). Multidimensional clinical, cognitive, psychomotor, metabolic, and neuroimaging data were evaluated (WHM burden and cerebral atrophy), and a cognitive-psychopathologic composite index was derived. Correlations and sensitivity analysis were performed. A multivariable linear regression was performed to assess the independent effects of age, vascular risk factors, and WMH severity on cognitive performance and psychiatric symptoms. Results: In patients with LO psychiatric disorders, greater WMH burden was significantly associated with poorer global cognition and specific cognitive domains, lower delusional symptoms severity, and greater suicidal thoughts/behavior intensity. These associations were markedly weaker or not present in EO patients. The regression model explained 36.5% of the variance in the cognitive-psychopathologic composite index. After adjusting for age and cumulative risk factors, Fazekas was the only significant independent predictor (β = −0.495, p = 0.001). Conclusions: WMH burden was associated with differences in clinical characteristics in LO psychiatric disorders, including cognitive and neuropsychiatric symptoms. Our findings support a possible vascular-neuropsychiatric interaction in LO phenotypes. Full article

Cardiogenic shock secondary to acute myocardial infarction complicated by mechanical failure remains associated with high mortality despite advances in cardiac surgery and mechanical circulatory support. We report the case of a 42-year-old patient with posterior papillary muscle rupture leading to severe mitral regurgitation, managed with emergency surgical intervention and extracorporeal membrane oxygenation. The patient, with a history of Type I Bipolar Disorder under long-term lithium therapy and chronic Cannabis use, presented in critical condition with cardiogenic shock (Killip IV), acute pulmonary edema, and ST-segment elevation myocardial infarction in the infero-posterior territory. Coronary angiography revealed right coronary artery occlusion and involvement of an obtuse marginal branch. Emergency mitral valve replacement with a mechanical prosthesis and aortocoronary bypass were performed. Due to failure to wean from cardiopulmonary bypass, central veno-arterial ECMO was initiated. The postoperative course was complicated by hemodynamic instability and recurrent pericardial collections requiring repeated surgical interventions and conversion to peripheral ECMO. Multiorgan dysfunction developed, including hepato-renal failure requiring hemofiltration, neurological injury, respiratory impairment, and neuropsychiatric complications. Despite these challenges, progressive recovery was achieved under intensive multidisciplinary management. This case emphasizes the importance of early surgical correction and tailored ECMO support in managing post-infarction mechanical complications. Full article

Background and Objectives: Bipolar disorder (BD) is associated with widespread neuroanatomical alterations, particularly within subcortical structures involved in emotional regulation. Conventional magnetic resonance imaging (MRI) approaches may fail to detect subtle microstructural changes. This study aimed to evaluate histogram-based texture characteristics of the putamen in patients with BD and to compare these findings with those of healthy controls. Materials and Methods: This retrospective cross-sectional study included 66 participants (33 BD patients, 33 controls). All subjects underwent standardized cranial MRI. Regions of interest corresponding to the putamen were manually delineated, and histogram-based texture parameters were extracted using custom-developed software. Group comparisons were performed using appropriate statistical tests based on data distribution. Results: The groups were comparable in age and sex (p > 0.05). Significant differences were observed in multiple texture parameters, particularly in the left putamen. Mean and median values were significantly higher in BD patients compared to controls (511.19 ± 106.96 vs. 440.68 ± 102.21, p = 0.008; 511.92 ± 106.71 vs. 440.53 ± 102.74, p = 0.007). Minimum intensity values and root-sum-of-squares levels were also significantly increased (p < 0.001). Skewness differed significantly (p = 0.004), indicating altered distribution asymmetry. Percentile analyses demonstrated consistent differences across nearly all levels, suggesting a shift in intensity distribution. Additionally, Katz fractal dimension was significantly lower in BD patients (p < 0.001), indicating reduced structural complexity. Similar but less pronounced alterations were observed in the right putamen. Overall, the findings suggest the presence of widespread alterations in intensity distribution and structural characteristics. Conclusions: Patients with BD exhibit significant alterations in putamen texture parameters, potentially reflecting alterations in intensity distribution and texture-derived structural characteristics. Histogram-based texture analysis may provide a sensitive, non-invasive approach for detecting subtle brain alterations in BD and may serve as a complementary neuroimaging biomarker. Full article

Mixed-scene holographic 3D display for film and television visual content presentation remains challenging because recorded digital holograms and computer-generated holograms (CGHs) are produced under different numerical and hardware constraints. Direct hologram superposition typically causes strong zero-order interference, diffraction efficiency degradation, and sampling pitch mismatch between the recording sensor and the replay panel, while conventional resizing reduces the effective replay aperture and narrows the available parallax. To address these issues, this paper proposes a zero-order-suppressed single-hologram fusion framework with parallax-preserving digital resizing. A recorded digital hologram is first processed by Gaussian high-pass filtering to suppress the dominant zero-order component, then resampled to match the LCOS replay pitch, and finally normalized and fused with a CGH generated through bipolar intensity encoding. On this basis, two resizing routes are developed: a spatial-domain method for aperture-preserving whole-scene scaling and a frequency-domain method for object-selective scaling and translation. Optical validation on a three-channel LCOS prototype shows that the quantitative diffraction efficiency analysis predicts an increase from approximately 10.1% to 20.05% per reconstructed object for the two-hologram fusion case, and the revised experimental results are consistent with this improvement trend. The experiments further verify replay scaling at multiple factors, the selective manipulation of physical and virtual objects, mixed-scene color replay, and occlusion-consistent depth ordering. Together with the distortion analysis, these results demonstrate improved replay visibility after fusion while maintaining geometric controllability and effective replay aperture. By relying on hologram-domain preprocessing and resizing rather than full mixed-scene recomputation, the proposed method also reduces computational burden. The study therefore provides an efficient and controllable mixed-scene holographic replay framework for visually enriched film and television content presentation, although its depth applicability remains bounded and dedicated real-time timing benchmarks are left for future work. Full article

A discrete Hartley transform (DHT)-based orthogonal frequency division multiplexing (OFDM) scheme is investigated for intensity modulation/direct detection (IM/DD) visible light communication (VLC) systems, where transmitted signals are required to be real-valued and non-negative. To address this constraint, a practical unipolar transmission framework with corresponding bipolar reconstruction is developed. By exploiting the real-valued and self-inverse properties of the DHT, the proposed scheme removes the need for Hermitian symmetry and enables full utilization of available subcarriers. Under equal-bandwidth conditions, this results in an approximately 50% reduction in computational complexity compared with conventional DCO-OFDM and ACO-OFDM schemes. Theoretical analysis and numerical results further show that the proposed approach achieves comparable bit error rate (BER) performance while exhibiting improved spectral confinement, as reflected by reduced out-of-band sidelobes under identical filtering conditions. In addition, it maintains spectral efficiency equivalent to DCO-OFDM under the same bandwidth constraint. These advantages are achieved at the cost of restricting subcarrier modulation to real-valued constellations, which may reduce flexibility in frequency-selective channels. Overall, these findings support DHT-OFDM as a low-complexity, spectrally confined multicarrier waveform for IM/DD VLC systems, particularly in scenarios where efficient spectrum utilization and reduced adjacent-channel interference are required. Full article

Light is the primary zeitgeber for circadian rhythms, and also through these mechanisms, is closely related to mood regulation. Bright light therapy (BLT) is a therapeutic intervention that specifically exploits this physiological mechanism. This review summarizes the clinical procedures of BLT, the mechanisms through which light influences circadian rhythms and mood, and the evidence supporting BLT in psychiatric disorders. BLT is administered by considering device distance, treatment duration, and light intensity. Through pathways originating in the retina and projecting to the Suprachiasmatic Nucleus (SCN), light might generate signals within the central nervous system that influence not only circadian regulation but also mood, via connections involving the limbic system, the lateral habenula, and interactions with the hormonal system. At the clinical level, the strongest evidence for BLT concerns seasonal affective disorder, but data also indicate antidepressant efficacy in major depressive disorder and bipolar disorder, with an excellent tolerability profile. Emerging evidence further suggests benefits for insomnia, and sporadic and heterogeneous findings have explored its potential role in other conditions. Future studies are needed to better define the role of BLT in additional psychiatric disorders and in specific symptom domains that may not adequately respond to standard treatments, such as sexual dysfunction. Full article

Bipolar Polymer Membranes (BPMs) enable the creation of large, stable pH gradients by driving water dissociation (WD) at the cation/anion junction under reverse bias, a process central to electrodialysis, CO₂ capture, and emerging acid–alkaline water electrolysis. Yet despite decades of study, the mechanism by which intense interfacial electric fields accelerate WD remains debated and is often modeled with ad hoc assumptions. In this study, we present a power dissipation model in which minority ions from water autoprotolysis act as carriers that continuously dissipate field-supplied power in the hydrated nanometric junction. This dissipative input increases the local probability of heterolytic O–H bond cleavage and analytically leads to a quadratic dependence of the dissociation rate constant on the field. Without adjustable parameters, the model reproduces the required orders of magnitude for the enhancement ratio k_d(E)/k_d(0), where k_d(E) is the field-enhanced water dissociation rate constant and k_d(0) is its zero-field value across typical BPM fields, and yields a quadratic current–voltage junction law. A proof-of-principle measurement on a commercial Fumasep^® FBM bipolar membrane confirms the quadratic current–voltage trend, supporting a power-dissipation-driven water dissociation mechanism and providing a concise, falsifiable baseline for future studies. Full article