Search Results (142)

Hemorrhoidal disease is a common anorectal condition that may require treatment when bleeding, prolapse or persistent symptoms fail to respond to conservative or office-based therapy. Radiofrequency ablation (RFA) has emerged as a minimally invasive, tissue-sparing technique for symptomatic internal hemorrhoids, based on controlled delivery of high-frequency energy into hemorrhoidal tissue. The resulting thermal effect induces coagulative necrosis, fibrosis, mucosal fixation and progressive reduction in hemorrhoidal volume, without excisional removal of anoderm or rectal mucosa. This narrative review summarizes the mechanism, technical principles, clinical advantages, comparative evidence and remaining uncertainties surrounding RFA, with particular attention to the Rafaelo procedure and related radiofrequency-based approaches. Current evidence suggests that RFA may reduce postoperative pain, analgesic requirements, wound-related morbidity, hospital stay and time to return to normal activity compared with conventional hemorrhoidectomy, while maintaining acceptable short- and mid-term symptom control in selected patients, especially those with grade II–III internal hemorrhoids. However, available studies remain heterogeneous in design, technique, patient selection, outcome definitions and follow-up duration. The relationship between modern probe-based RFA and earlier radiofrequency-based approaches, including Ellman surface coagulation, Celon bipolar radiofrequency-induced thermotherapy and radiofrequency-assisted hemorrhoidectomy, remains insufficiently standardized in the literature. Further randomized trials, standardized outcome reporting, long-term recurrence data and cost-effectiveness analyses are required to define the optimal indications and therapeutic position of RFA. Full article

This study presents a comprehensive computational evaluation of radiofrequency (RF) ablation efficacy and the spatial formation of thermal ablation zones within a 3D model of a liver tumor. By systematically comparing these configurations, the study aims to elucidate the physical mechanisms governing electromagnetic (EM) energy dissipation in hepatic tissue and to provide clear engineering guidelines for optimizing RF applicator selection and treatment planning in clinical practice. To reliably simulate the biophysical phenomena of the RF ablation procedure, a coupled electro-thermal model based on the finite element method and the Pennes bioheat equation was implemented. The research investigates six distinct applicator variants: conventional needle-type applicators and advanced expandable umbrella-type RF applicators equipped with four- and eight-tine electrodes, each evaluated in both monopolar and bipolar configurations. Numerical simulations were conducted for a standard 10 min ablation procedure at varying applied voltages to assess the specific absorption rate (SAR) distribution, transient heating dynamics, and the exact volumes of the resulting coagulation necrosis which were quantified using rigorous isotherms and the cumulative equivalent minutes at 43 °C (CEM₄₃) thermal dose index. Volumetric analysis of the ablation zones revealed that bipolar multi-tine electrodes induce highly localized heat concentration. Conversely, monopolar multi-tine setups strongly disperse EM energy. The results demonstrated that, for conventional needle applicators, the monopolar configuration generated significantly larger necrosis zones than the bipolar operating mode. The RF applicator geometry and its operating mode directly dictate the spatial extent of liver tissue necrosis. Moreover, advanced numerical treatment planning is essential for optimizing SAR and CEM₄₃ distributions and ensuring safe and complete hepatocellular carcinoma eradication. Full article

In this article, the different types of self-coagulation discovered in the fluid simulations of inductively coupled plasma (abbreviated as ICP) at both the electronegative and electropositive cases are presented. Among these, the electronegative plasma sources include Ar/O₂, Ar/Cl₂, and Ar/SF₆, and the electropositive plasma source is the inertial argon plasma itself. The fluid simulation versions are not the same. Concretely, the Comsol software version 5.4 is used to simulate the Ar/O₂, Ar/Cl₂, Ar/SF₆, and the pure argon ICPs, and the self-written code of the fluid model is used to simulate the pure argon ICP as well, but in a different framework of fluid design. The types of self-coagulation refined from these fluid simulations are the physically ambi-polar self-coagulation of ions, the chemically ambi-polar self-coagulation of ions, the mono-polar self-coagulation of electrons, and the non-polar self-coagulation of argon metastable atoms. These self-coagulations are based on mass and founded through the Comsol fluid simulations, and moreover, the self-coagulation of thermal energy of electrons is founded through the self-written fluid code simulation. Based on the self-coagulations of mass and energy, together with the accompanying discharge hierarchy, we hypothesize (1) the correlation of ambi-polar self-coagulation and diffusion, (2) the mean of using the Schrodinger equation to describe the quasi-particle of anions given by self-coagulation in a certain potential barrier, (3) the analogy of the $\beta$ and ${\beta }^{+}$ decay and the asymmetry given by two types of ICP source simulation, (4) the picture of spin orientations of neutrino and anti-neutrino, and (5) the model for photon sustainment. The self-coagulation behavior is seen to be general and the interdisciplinary works of plasma physics with quantum mechanics, particle physics, nuclear physics, and optics are helpful for us to better understand the mass and energy general dynamics. Full article

Microplastic contamination in soils is an emerging environmental challenge requiring effective and scalable remediation strategies. This review synthesizes advances in physical, chemical, biological, and hybrid approaches, focusing on mechanisms, performance, and practical applicability. Physical methods, particularly adsorption using biochar, achieve removal efficiencies exceeding 86% for 1 μm polystyrene microplastics and maintain > 85% efficiency after multiple reuse cycles, demonstrating strong durability. Filtration and aggregation systems, such as permeable reactive barriers, reach up to 81.55% removal but are less effective in co-contaminated conditions. Chemical strategies exhibit the highest efficiencies. Dielectric barrier discharge plasma achieves 96.5–98.7% degradation within 30–60 min, while electrochemical coagulation reaches ~98% removal via flocculation. Thermal treatments, including pyrolysis, enable near-complete microplastic removal (~100%) at ≥400 °C, although high energy demands limit in situ application. Chemical amendments also improve soil quality, increasing organic matter by ~7.35% and enhancing nutrient availability. Biological approaches offer sustainable but slower remediation. Microbial degradation achieves up to ~60% breakdown within 21 days, while enzyme–microbe systems reach ~21.4% over 60 days. Earthworm activity enhances fragmentation and nutrient cycling (up to 36.1%), whereas phytoremediation alone shows minimal direct degradation (<1% over 12 months). Hybrid strategies, particularly biochar-based systems, provide the most practical solutions by combining adsorption, microbial stimulation, and soil restoration, but their effectiveness in degrading microplastics needs further verification. These systems enhance microbial biomass (up to 57.67%), nutrient availability (up to 66.02%), and crop yield (up to 81.41%). Overall, physicochemical methods ensure rapid removal (>90%), biological approaches support long-term degradation, and hybrid systems offer scalable, sustainable remediation for field applications. Full article

Background: Radiofrequency ablation of liver tumors relies on tightly coupled electromagnetic–thermal dynamics. However, conventional computational models oversimplify tissue heterogeneity and the dynamic evolution of biophysical properties, limiting their intraoperative diagnostic utility. Methods: We developed a patient-specific, three-dimensional multiphysics framework for liver RFA that integrates spatially varying tissue porosity with a modified local thermal equilibrium formulation. Advective heat transfer is computed via a supplementary finite-element equation, fully coupled with quasi-static electromagnetic simulations and Arrhenius-based tissue damage kinetics. Results: Simulations revealed three distinct voltage-dependent regimes: stable thermal–electromagnetic coupling at 50 V, optimal lesion expansion at 75 V, and premature electrical conductivity collapse at 100 V. Dynamic conductivity reduction, driven by dehydration and coagulative necrosis, provides a mechanistic basis for interpreting real-time impedance rises as an early indicator of peri-electrode desiccation. Geometry-constrained porosity mapping accurately reproduced anisotropic lesion morphologies, yielding simulated necrotic diameters of 2.8 ± 0.4 cm, closely aligning with MRI-validated clinical benchmarks. Conclusions: By linking microstructural heterogeneity to electromagnetic feedback, this framework transforms intraoperative impedance monitoring into a quantitative, predictive diagnostic tool. Imaging-derived spatial porosity mapping represents a robust biomarker for patient-specific liver RFA planning, significantly reducing procedural uncertainty and improving ablation precision. Full article

Lignin is an abundant aromatic biopolymer, but its conversion into high-performance fibers remains challenging due to intrinsically poor spinnability, structural heterogeneity, and inefficient stress transfer in lignin-rich systems. In this study, a processing and structure strategy is demonstrated to overcome these limitations by transforming industrial black-liquor kraft lignin into a spinnable and load-bearing fiber component. Kraft lignin recovered from black-liquor waste was extracted and subsequently purified using a hot-water treatment to remove inorganic impurities and thermally unstable fractions, increasing lignin purity to 95.9% through extensive deionized water purification using a water-to-lignin ratio of 300:1. The purified lignin was then blended with poly(vinyl alcohol) (PVA), wet-spun into continuous filaments, and subjected to post-spinning hot drawing to induce molecular orientation. This sequential extraction, purification, blending, spinning, and drawing approach enables stable wet spinning and the continuous formation of lignin-rich lignin/PVA filaments without filament breakage, directly addressing the primary processing bottleneck of lignin-based fibers. Molecular-level miscibility between lignin and PVA is confirmed by the presence of a single glass transition temperature at 88.3 °C, indicating the formation of a homogeneous amorphous phase. SEM observations reveal composition-dependent surface roughness and non-circular cross-sectional morphologies arising from differential coagulation and shrinkage, demonstrating that lignin actively participates in the load-bearing fiber network rather than acting as a passive filler. As a result of purification-enabled spinnability, true blend miscibility, and post-spinning hot drawing, fibers with a lignin-to-PVA composition of 40:60 achieve a maximum tensile strength of 2.8 GPa, approaching the performance range of commercial high-strength polymer fibers. This work establishes a clear relationship between material structure, processing strategy, and resulting properties, highlighting the potential of industrial lignin waste as a sustainable precursor for advanced fiber applications. Full article

This paper evaluates the advantages of overlapping microwave ablation (OMWA) for the personalized treatment of large tumors, providing quantitative and technical references for conformal tumor eradication. A three-dimensional numerical model coupled with electromagnetic fields and Pennes’ biological heat transfer equation was constructed, comprehensively considering the nonlinear behavior of tissue electrical and thermal parameters with temperature changes. A simulation model was developed to predict temperature distribution and the formation of the coagulation zone under single-needle multiple-point and multiple-needle multiple-point OMWA strategies. The LiTS2017 public dataset of liver tumor cases and real clinical cases was selected for verification. The results showed that OMWA could achieve faster thermal accumulation, higher central temperature, and more conformal tumor coverage. Compared with the single-needle strategy, OMWA significantly reduces thermal damage to surrounding healthy tissues while achieving complete tumor coverage. Therefore, OMWA is more efficient and safer than the single-needle strategy in the personalized treatment of large tumors and can provide important references for clinical preoperative planning and parameter optimization. Full article

Cadmium contamination of water resources represents a serious environmental and public health challenge, with conventional treatment methods often proving inadequate for industrial-level remediation. In this study, we present a novel, sustainable composite material, functionalized cellulose nanocrystal polyvinyl alcohol zinc oxide ferric chloride (CNC-PVA-ZnOFe) beads for the efficient removal of cadmium from contaminated water. The material integrates adsorption, coagulation, and flocculation mechanisms within a single hybrid platform, with coagulation–flocculation serving as the dominant mechanism given the material’s macroporous structure and limited surface area (1.2–3.3 m²/g). Functionalized cellulose nanocrystals provide supporting adsorptive sites for metal binding, while a PVA matrix incorporating ZnOFe improves structural integrity, mechanical stability, and coagulation performance. Characterization confirmed successful functionalization, enhanced thermal stability, and a macroporous structure (12–52 nm pores) conducive to floc entrapment, though with limited surface area (1.2–3.3 m²/g) for conventional adsorption. Under optimized conditions (pH 7–10, initial Cd²⁺ concentration of 100 mg/L, coagulant dose of 0.1 g, and sedimentation time of 60 min), the functionalized CNC-PVA-ZnOFe beads achieved a cadmium removal efficiency of 78%, achieving significantly higher cadmium removal efficiency than traditional coagulants, such as aluminum sulfate (69%). The beads also demonstrated good reusability, retaining 85% removal efficiency after five regeneration cycles. This work presents a scalable, eco-friendly material for cadmium removal under controlled laboratory conditions using synthetic solutions. However, further evaluation in real wastewater matrices containing competing ions and organic matter is necessary to establish practical applicability for water treatment applications. The study highlights the combined potential of multifunctional hybrid materials while acknowledging the need for validation under environmentally relevant conditions. While the results indicate successful integration of multiple removal mechanisms, direct validation of synergistic interactions through techniques such as zeta potential and XPS analysis remains an important direction for future research. Full article

Bipolar forceps, powered by high-frequency alternating electrical current, are the main tools for electrocoagulation in surgical operations. Coagulation occurs through thermal heating; however, excessive temperatures can induce tissue damage. The study aims to measure the temperature increment between bipolar forceps’ tips on ex vivo biological tissues from the liver and white and grey matter of the calf brain. Three forceps, disposable and reusable, are tested using electrical power of 5, 10 and 15 W applied for 5 s, penetrating 1 mm into the tissue; the same procedure is followed for all the 135 tests performed. Infrared thermal measurements are collected during the transient, statistically analyzed in terms of the median and scatter of the peak temperatures, and compared among the forceps types. The outcomes allow evidence that disposable forceps are more performing than reusable ones for all tissues, e.g., limit excessive thermal heating and experience lower scatter, potentially reducing the risk of unintended injury to adjacent or peripheral tissues when applied in surgical operations. Full article

Physics-based simulations are increasingly used to improve understanding of electrosurgical processes and to enable model-based estimation of tissue state when direct sensing is limited. The performance of such simulation-based virtual sensing approaches strongly depends on an accurate representation of the electrode–tissue interface. Despite its central role in electrical and thermal coupling, the influence of the electrode–tissue contact area has received limited attention in existing simulation studies. In this work, the influence of the electrode–tissue contact area on the sensitivity of key temperature-dependent tissue parameters was investigated for electrosurgical monopolar soft coagulation. Using a multiphysics finite element model under controlled boundary conditions, the sensitivity of maximum temperature development and necrotic tissue volume formation was analyzed with respect to varying contact areas and initial values of electrical conductivity, thermal conductivity, and effective heat capacity. The results demonstrate that parameter sensitivities are strongly contact-area-dependent. Electrical conductivity exhibits the most pronounced influence, particularly at larger contact areas, while thermal conductivity remains of minor relevance. In contrast, effective heat capacity significantly affects necrotic tissue volume formation, with increasing sensitivity for larger contact areas. These findings emphasize the importance of accurately accounting for electrode–tissue contact conditions in simulation-based analyses and clarify how contact-area-dependent sensitivities influence model-based tissue state estimation in electrosurgical coagulation. Full article

Perchlorate (ClO₄⁻) is difficult to remove efficiently using conventional treatment technologies, such as coagulation and reverse osmosis, due to its high water solubility and exceptional chemical stability. Quaternary ammonium resins have emerged as cost-effective and efficient materials for ClO₄⁻ removal; therefore, the development of high-performance quaternary ammonium resins is critical for improving ClO₄⁻ remediation. In this study, a novel resin (PS-QA) was synthesized by aminating poly (vinylbenzyl chloride) with N,N-dimethylethanolamine, and its adsorption performance was systematically compared with that of three internationally recognized commercial ClO₄⁻ removal resins. Although all four resins exhibited spherical morphologies, the polystyrene backbone exhibited strong hydrophobicity, and the functional group –[R-N⁺(CH₃)₂(C₂H₄OH)]Cl⁻ possesses good electrophilicity, thereby conferring excellent selectivity toward ClO₄⁻. PS-QA exhibited a specific surface area of 19.94 m²/g, an average pore diameter of 32 nm, and a pore volume of 0.157 cm³/g, indicating comparable adsorption performance relative to the commercial counterparts. Its high thermal stability was further demonstrated through thermogravimetric analysis. Adsorption equilibrium was reached within 60 min, and the kinetic performance of PS-QA was comparable to that of the commercial resins. Isotherm analysis showed that ClO₄⁻ adsorption conformed to the Freundlich model, suggesting a coupled physical–chemical adsorption mechanism. Moreover, PS-QA exhibited both strong resistance to interference in complex water matrices and excellent reusability. After three adsorption–desorption cycles, more than 80% of the adsorption sites remained active. Notably, PS-QA also demonstrated outstanding performance in pilot-scale applications. Full article

Antarctic krill oil (AKO) is a valuable nutraceutical; however, it is highly susceptible to oxidation. Encapsulation represents an effective strategy to enhance the storage stability of AKO. This study explored a novel approach for encapsulating AKO using sodium alginate (ALG) and gelatin (GLN) to improve its stability, and multiple parameters were systematically evaluated, including oil-loading efficiency, surface oil content, particle size, water activity, and thermal stability. Additionally, core-material retention efficiency, acid value, peroxide value, and anisidine value were measured after accelerated oxidation. The results demonstrated that the optimal encapsulation conditions consisted of an ALG:GLN ratio of 2:1, a 9% CaCl₂ coagulation bath, 750 μm nozzle size, followed by freeze-drying. Under these conditions, the microcapsules achieved an oil-loading efficiency of 62.63% and a surface oil content of 19.21%. The water activity of the microcapsules was 0.516. Thermogravimetric analysis indicated that AKO microcapsules encapsulated with ALG/GLN exhibited higher thermal stability (~300 °C) compared to those encapsulated with ALG alone (~280 °C). When AKO or its microcapsules were subjected to accelerated oxidation at 65 °C, compared to ALG-encapsulation alone, the ALG/GLN encapsulation system significantly reduced the oxidation indicators of the oil, such as acid value (24%), peroxide value (26%), and anisidine value (28%). In conclusion, incorporating GLN into ALG-based microcapsules significantly enhanced the antioxidant capacity of AKO and prolonged its shelf life. Full article

Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal malignancy due to late presentation, limited resectability, therapeutic resistance, and a dense desmoplastic immunosuppressive tumor microenvironment that impairs drug penetration and antitumor immunity. Focused ultrasound (FUS) is an emerging non-invasive, image-guided therapeutic platform capable of delivering spatially confined acoustic energy to induce tumor ablation, disrupt stromal barriers, and enhance delivery of drugs, nanoparticles, and nucleic acids. Depending on acoustic parameters, FUS can produce thermal effects resulting in coagulative necrosis or non-thermal mechanical effects, including cavitation, sonoporation, and histotripsy which remodel extracellular matrix architecture, increase vascular and cellular permeability, and facilitate tumor debulking. In addition, FUS-induced cell injury can promote immunogenic cell death and release tumor-associated antigens and danger signals, providing a rationale for combination strategies with chemotherapy, radiation, and immunotherapy. This review synthesizes the mechanistic foundations, preclinical modeling advances, and emerging clinical applications of FUS in PDAC, with emphasis on treatment integration, patient selection, real-time monitoring, and acoustic parameter optimization, while acknowledging current safety considerations and limited clinical toxicity data. Key limitations, translational challenges, and priority knowledge gaps are also discussed to define the role of FUS in multimodal PDAC care. Full article

Malignancy-related gastrointestinal bleeding (GIB) remains a significant clinical challenge, contributing substantially to morbidity, mortality, and healthcare utilization in patients with cancer. Up to 10% of individuals with advanced malignancies develop GIB during their disease, and these episodes are frequently characterized by a high risk of rebleeding and poor long-term hemostatic control. Tumor-associated bleeding typically arises from friable, infiltrative, and highly vascular lesions that respond suboptimally to conventional endoscopic techniques such as thermal coagulation or mechanical clipping. These limitations underscore the need for improved diagnostic accuracy and more reliable therapeutic options. Recent advances in imaging modalities, including contrast-enhanced CT studies, have enhanced the ability to localize and characterize bleeding sources in complex oncologic cases. Parallel developments in endoscopic hemostasis—such as over-the-scope clips and contact-free coagulation devices—have expanded the therapeutic armamentarium for managing malignant bleeding. Clinically, topical hemostatic powders—particularly TC-325—represent a highly effective option for achieving rapid endoscopic hemostasis, supported by the strongest comparative evidence and the highest rates of immediate bleeding control among currently available technologies. In this review, we synthesize contemporary diagnostic approaches to GIB and place particular emphasis on the evolving and emerging therapeutic strategies for malignancy-related bleeding. We also highlight innovative technologies that are reshaping clinical practice and improving management options in this challenging clinical domain. Full article

Background: Thromboembolic events, though infrequent, remain a significant complication of atrial fibrillation (AF) ablation, largely related to endothelial damage. Cryoballoon (CB) and radiofrequency ablation can induce pro-coagulant responses, whereas pulsed-field ablation (PFA), a novel non-thermal electroporation-based technique, has shown tissue selectivity with potential endothelial-sparing effects. Methods: We aimed to compare PFA and second-generation CB ablation regarding endothelial injury in patients with paroxysmal AF. In this single-center prospective observational study, 25 patients with paroxysmal drug-refractory AF underwent pulmonary vein isolation using either a pentaspline PFA catheter (n = 14) or a second-generation CB catheter (n = 11). Circulating von Willebrand factor antigen (vWF) levels were assessed before and after ablation as a biomarker of endothelial damage, alongside routine laboratory and echocardiographic parameters. Procedural characteristics were also analyzed. Results: Baseline demographic, clinical, and echocardiographic data were comparable between groups. PFA was associated with significantly shorter skin-to-skin procedure time (59 vs. 94 min, p = 0.005) and left atrial dwell time (44 vs. 79 min, p < 0.001) compared with CB ablation. Importantly, vWF levels decreased significantly after PFA (−7.6%, p = 0.007), while CB ablation showed a non-significant increase (+9.5%, p = 0.155). The between-group difference in percent change of vWF was statistically significant (−5.6% vs. +8.3%, p = 0.006). Conclusions: PFA was associated with reduced endothelial injury and shorter procedural times compared with CB ablation, suggesting a potential advantage in lowering thromboembolic risk. These findings support the concept of PFA as an “endothelial sparing” ablation modality. However, the PFA procedure was associated with a significantly greater extent of myocardial injury, as reflected in circulating high-sensitivity cardiac troponin T values, compared to CB ablation (p = 0.007). Larger, randomized studies are warranted to confirm these results and evaluate long-term clinical outcomes. Full article