Search Results (2,022)

Background: The influence of the initial ablation modality on pulmonary vein (PV) reconnection and substrate characteristics in redo procedures for recurrent atrial fibrillation (AF) remains unclear. We assessed how different thermal strategies—ablation index (AI)-guided radiofrequency (RF) versus cryoballoon (CB) ablation—affect remapping findings during redo pulmonary vein isolation (PVI). Methods: We included patients undergoing redo ablation between 2015 and 2024 with high-density electroanatomic mapping. Initial PVI modalities were retrospectively classified as low-power, long-duration (LPLD) RF; high-power, short-duration (HPSD) RF; or second-/third-generation CB. Reconnection sites were mapped using multielectrode catheters. Redo PVI was performed using AI-guided RF. Segments showing PV reconnection were reisolated; if all PVs remained isolated and AF persisted, posterior wall isolation was performed. Results: Among 195 patients (LPLD: 63; HPSD: 30; CB: 102), complete PVI at redo was observed in 0% (LPLD), 23.3% (HPSD), and 10.1% (CB) (p < 0.01 for LPLD vs. HPSD). Reconnection patterns varied by technique; LPLD primarily affected the right carina, while HPSD and CB showed reconnections at the LSPV ridge. Organized atrial tachycardia was least frequent after CB (12.7%, p < 0.002). Conclusion: Initial ablation strategy significantly influences PV reconnection and post-PVI arrhythmia patterns, with implications for redo procedure planning. Full article

Background/Objectives: Sarcopenia is defined by the progressive loss of muscle mass, strength, and/or physical performance associated with aging. Radiofrequency ablation (RFA) of the medial branch nerves is a well-established and effective treatment for lumbar facetogenic pain. While sarcopenia is associated with poor outcomes following epidural steroid injections and lumbar spine surgeries, its impact on clinical outcomes in patients undergoing RFA for facetogenic pain remains unexplored. This study aims to evaluate the influence of sarcopenia on treatment outcomes in this patient cohort. Methods: Patients were classified into sarcopenia (n = 35) and non-sarcopenia groups (n = 67) based on predefined psoas muscle index (PMI) thresholds. The primary outcomes included changes in back pain intensity and the proportion of responders at 1, 3, and 6 months following RFA. The secondary outcome was to identify demographic, clinical, and sarcopenia-related factors predictive of treatment response at each follow-up interval. Results: Both groups demonstrated statistically significant improvements in pain scores compared to baseline at all follow-up points. However, the median pain scores at 3 months post-RFA remained significantly higher in the sarcopenia group. Despite this, the proportion of responders did not differ significantly between the two groups at any time point. At 3 months, the absence of prior spinal surgery was identified as a significant predictor of treatment response. At 6 months, favorable outcomes were significantly associated with the absence of diabetes, no history of spinal surgery, and a higher PMI. Conclusions: Sarcopenia may influence the extent of pain improvement following medial branch nerve RFA. Additionally, patient-specific factors, such as diabetes, prior spinal surgery, and PMI, should be considered when predicting treatment outcomes. Full article

This paper serves as a comprehensive and practical resource to guide researchers in selecting suitable metals for use as photocathodes in radio-frequency (RF) and superconducting radio-frequency (SRF) electron guns. It offers an in-depth review of bulk and thin-film metals commonly employed in many applications. The investigation includes the photoemission, optical, chemical, mechanical, and physical properties of metallic materials used in photocathodes, with a particular focus on key performance parameters such as quantum efficiency, operational lifetime, chemical inertness, thermal emittance, response time, dark current, and work function. In addition to these primary attributes, this study examines essential parameters such as surface roughness, morphology, injector compatibility, manufacturing techniques, and the impact of chemical environmental factors on overall performance. The aim is to provide researchers with detailed insights to make well-informed decisions on materials and device selection. The holistic approach of this work associates, in tabular format, all photo-emissive, optical, mechanical, physical, and chemical properties of bulk and thin-film metallic photocathodes with experimental data, aspiring to provide unique tools for maximizing the effectiveness of laser cleaning treatment. Full article

The electrical ventricular storm (VES) is defined as multiple sustained ventricular arrhythmias arising in a short time, often refractory to standard antiarrhythmic treatment. The three pillars of the physiopathogenesis of the VES are autonomic dysfunction, triggers, and an altered ventricular substrate. Incessant or highly recurrent ventricular arrhythmia impacts the hemodynamic status by worsening heart failure and increasing mortality. A stepwise, team-based, and tailored therapeutic approach is required to stop ventricular arrhythmia and regain the hemodynamic and electric stability of the patient. The authors focused on describing all currently available therapeutic approaches for VES, intending to establish the best VES therapeutic approaches. This process involves considering the patient’s specific condition, responses to previous treatments, and the potential risks and benefits of each approach. The options range from adjusting antiarrhythmic therapy to reprogramming of the ICD, sedation, epidural anaesthesia, stellate ganglia anaesthetic block, and the use of ECMO or left ventricular assist devices and radiofrequency catheter ablation. Particular attention is paid to the detailed management of genetic primary arrhythmia syndromes like long-QT syndrome, catecholaminergic polymorphic ventricular tachycardia, Brugada syndrome and Wolff–Parkinson–White syndrome, early repolarisation syndrome, right ventricular arrhythmogenic dysplasia, and idiopathic ventricular fibrillation. After overcoming the acute events of VES and obtaining hemodynamic stability, the treatment should shift toward an optimal balance of heart failure therapy, controlling the substrate by revascularisation procedures and resolving other pathology-generating ventricular arrhythmias. This article provides a comprehensive overview of ESV’s current management options using the most efficient strategies known to date. Full article

AlGaN-based high-electron-mobility transistors are critical for next-generation power electronics and radio-frequency applications, yet achieving stable enhancement-mode operation with a high threshold voltage remains a key challenge. In this work, we designed p-AlGaN superlattices with different structures and performed energy band structure simulations using the device simulation software Silvaco. The results demonstrate that thin barrier structures lead to reduced acceptor incorporation, thereby decreasing the number of ionized acceptors, while facilitating vertical hole transport. Superlattice samples with varying periodic thicknesses were grown via metal-organic chemical vapor deposition, and their crystalline quality and electrical properties were characterized. The findings reveal that although gradient-thickness barriers contribute to enhancing hole concentration, the presence of thick barrier layers restricts hole tunneling and induces stronger scattering, ultimately increasing resistivity. In addition, we simulated the structure of the enhancement-mode HEMT with p-AlGaN as the under-gate material. Analysis of its energy band structure and channel carrier concentration indicates that adopting p-AlGaN superlattices as the under-gate material facilitates achieving a higher threshold voltage in enhancement-mode HEMT devices, which is crucial for improving device reliability and reducing power loss in practical applications such as electric vehicles. Full article

Radio frequency (RF)-based wireless systems are broadly used in communication systems such as mobile networks, satellite links, and monitoring applications. These systems offer outstanding advantages over wired systems, particularly in terms of ease of installation. However, researchers are looking for safer alternatives as a result of worries about possible health problems connected to high-frequency radiofrequency transmission. Using the visible light spectrum is one promising approach; three cutting-edge technologies are emerging in this regard: Optical Camera Communication (OCC), Light Fidelity (Li-Fi), and Visible Light Communication (VLC). In this paper, we propose a Multiple-Input Multiple-Output (MIMO) modulation technology for Internet of Things (IoT) applications, utilizing an LED array and time-domain on-off keying (OOK). The proposed system is compatible with both rolling shutter and global shutter cameras, including commercially available models such as CCTV, webcams, and smart cameras, commonly deployed in buildings and industrial environments. Despite the compact size of the LED array, we demonstrate that, by optimizing parameters such as exposure time, camera focal length, and channel coding, our system can achieve up to 20 communication links over a 20 m distance with low bit error rate. Full article

Background and Objectives: Morton’s neuroma is a painful foot condition that can be treated with continuous radiofrequency. However, its efficacy is not always optimal, with failure rates of 15–20%. It has been suggested that these failures may be due to incomplete nerve ablation, allowing for nerve regeneration and persistent pain. So, the aim of this study was to assess the histological effects of continuous radiofrequency on the nerves affected by Morton’s neuroma. Materials and Methods: The effect of continuous radiofrequency was evaluated in two patients with Morton’s neuroma, which required open surgery excision. In both cases, radiofrequency with a standard protocol was applied ex vivo, following the surgical excision of the neuroma. A TLG10 RF generator (90 °C, 90 s) with a monopolar needle with a 0.5 cm active tip was used. Subsequently, the samples were histologically analyzed to determine the degree of nerve ablation. Results: Histological analysis showed homogeneous focal necrosis in both cases, with lesion depths of 2.4 mm and 3.18 mm. However, areas of intact nerve tissue were identified at the periphery of the neuroma, suggesting incomplete ablation. Conclusions: The findings indicate that continuous radiofrequency does not guarantee total nerve ablation, which could explain recurrence in some cases. Intraoperative neurophysiological monitoring could be key to optimizing the procedure, ensuring complete interruption of nerve conduction and improving treatment efficacy. Full article

The global coffee supply chain is a complex multi-stakeholder ecosystem plagued by fragmented records, unverifiable origin claims, and limited real-time visibility. These limitations pose risks to ethical sourcing, product quality, and consumer trust. To address these issues, this paper proposes a blockchain and IoT-enabled framework for secure and transparent coffee supply chain management. The system integrates simulated IoT sensor data such as Radio-Frequency Identification (RFID) identity tags, Global Positioning System (GPS) logs, weight measurements, environmental readings, and mobile validations with Ethereum smart contracts to establish traceability and automate supply chain logic. A Solidity-based Ethereum smart contract is developed and deployed on the Sepolia testnet to register users and log batches and to handle ownership transfers. The Internet of Things (IoT) data stream is simulated using structured datasets to mimic real-world device behavior, ensuring that the system is tested under realistic conditions. Our performance evaluation on 1000 transactions shows that the model incurs low transaction costs and demonstrates predictable efficiency behavior of the smart contract in decentralized conditions. Over 95% of the 1000 simulated transactions incurred a gas fee of less than ETH 0.001. The proposed architecture is also scalable and modular, providing a foundation for future deployment with live IoT integrations and off-chain data storage. Overall, the results highlight the system’s ability to improve transparency and auditability, automate enforcement, and enhance consumer confidence in the origin and handling of coffee products. Full article

Background: Pulsed field ablation (PFA) is a novel non-thermal modality for pulmonary vein isolation (PVI) in atrial fibrillation (AF), offering myocardial selectivity through irreversible electroporation while sparing surrounding structures. However, concerns have emerged regarding potential subclinical hemolysis, reflected by alterations in biochemical markers such as lactate dehydrogenase (LDH). Methods: We conducted a retrospective, single-center study involving 249 patients undergoing PVI: 121 treated with PFA (PulseSelect or FARAPULSE) and 128 with radiofrequency (RF) ablation (PVAC catheter). Laboratory parameters were assessed at baseline, post-procedure, and at discharge, including hemoglobin, hematocrit, red blood cell (RBC) count, platelet count, creatinine, and LDH. The primary endpoint was the variation in blood cell indices; the secondary endpoint was the evaluation of LDH and hematocrit changes. Statistical analysis included t-tests and chi-square tests. Results: Baseline characteristics and pre-procedural labs did not differ significantly between groups. No significant changes in hemoglobin, hematocrit, RBC count, platelet count, or creatinine were observed post-ablation or at discharge. However, LDH levels significantly increased in the PFA group both post-procedurally and at discharge (p < 0.001), without concurrent changes in other blood cell parameters. Conclusions: PFA and RF ablation yield comparable hematological profiles after PVI, with no significant impact on key blood cell parameters. Nonetheless, the consistent rise in LDH levels in the PFA group suggests mild, subclinical hemolysis or tissue injury due to more extensive lesions. While supporting the hematologic safety of PFA, these findings underscore the need for further studies to assess the clinical significance of these biochemical alterations, particularly in high-risk patients or extensive ablation settings. Full article

Despite advances in surgery, chemotherapy, and radiation treatments for pancreatic ductal adenocarcinoma (PDAC), 5-year survival rates remain at nearly 11%. Cholangiocarcinoma, while not as severe, also possesses similar survival rates. Fewer than 20% of patients are surgical candidates at time of diagnosis; therefore, it is imperative that alternative therapies are effective for non-surgical patients. There are several thermal ablative techniques, including radiofrequency ablation (RFA), high-intensity focused ultrasound (HIFU), microwave ablation (MWA), alcohol ablation, stereotactic body radiotherapy (SBRT), cryoablation, irreversible electroporation (IRE), biliary intraluminal brachytherapy, and biliary photodynamic therapy (PDT). Emerging literature in animal models and human patients has demonstrated that endoscopic ultrasound (EUS)-guided RFA (EUS-RFA) prevents tumor progression through coagulative necrosis, protein denaturation, and activation of anticancer immunity in local and distant tumor tissue (abscopal effect). RFA treatment has been shown to not only reduce tumor-associated immunosuppressive cells but also increase functional T cells in distant tumor cells not treated with RFA. The remarkable ability to reduce tumor progression and promote tumor microenvironment (TME) remodeling makes RFA a very promising non-surgical therapy technique that has the potential to reduce mortality in this patient population. EUS-RFA offers superior precision and safety compared to other ablation techniques for pancreatic and biliary cancers, due to real-time imaging capabilities and minimally invasive nature. Future research should focus on optimizing RFA protocols, exploring combination therapies with chemotherapy or immunotherapy, and expanding its use in patients with metastatic disease. This review article will explore the current data and underlying pathophysiology of EUS-RFA while also highlighting the role of ablative therapies as a whole in immune activation response. Full article

Background/Objectives: “Ozempic face” is an aesthetic side effect associated with the use of the antidiabetic agent Ozempic (semaglutide), characterized by a prematurely aged and fatigued facial appearance due to rapid weight loss. Currently, treatment options for this condition are limited. In this study, we present our clinical experience with the BodyTite device, provided by InMode Italy S.r.l. (Rome, Italy). Materials and Methods: We report a case series involving 24 patients (19 women and 5 men, aged 27–65 years), treated with subdermal bipolar radiofrequency (Endotissutal Bipolar Radiofrequency) between 2023 and 2024. All patients underwent a minimum follow-up of 12 months. At the end of the follow-up period, patients rated their satisfaction on a from 0 to 10 scale, and an independent expert assessed the stability of clinical outcomes. Results: The majority of patients reported high satisfaction levels (≥8), which correlated with the independent expert’s evaluation of treatment efficacy and result stability. The only observed adverse event was transient cutaneous erythema. Conclusions: “Ozempic face” is an increasingly common side effect associated with newer classes of antidiabetic medications. Although these drugs offer significant metabolic benefits, the accompanying facial volume loss and aging are often poorly tolerated by patients. Our findings suggest that subdermal bipolar radiofrequency represents a safe, low-risk, and cost-effective therapeutic option for the aesthetic management of Ozempic face. Full article

The investigations examined a potential reduction in discrepancies between the values of the unperturbed radiofrequency (RF) electromagnetic field (EMF) and values of the EMF measured by wearable equipment (personal exposure meters) impacted by the proximity of the human body. This was done by modelling distributed wearable (multi-location, with up to seven simultaneously locations) measurements. The performed numerical simulations mimicked distributed measurements in 24 environmental exposure scenarios (recognized as virtual measurements) covered: the horizontal or vertical propagation of the EMF and electric field vector polarization corresponding to typical conditions of far-field exposure from wireless communication systems (at a frequency of 100–3600 MHz). Physical tests using three EMF probes for simultaneous measurements have been also performed. Studies showed that the discrepancy in assessing EMF exposure by an on-body equipment and the parameters of the unperturbed EMF in the location under inspection (mimicking the contribution to measurement uncertainty from the human body proximity) may be significantly reduced by the appropriate use of a distributed measurement system. The use of averaged values, from at least three simultaneous measurements at relevant locations on the body, may reduce the uncertainty approximately threefold. Full article

Coronary artery disease (CAD) is the third leading cause of disability and death globally. Intravascular ultrasound (IVUS) is the most commonly used imaging modality for the characterization of vulnerable plaques. The development of novel intravascular imaging and therapy devices requires dedicated open systems (e.g., for pulse sequences for imaging or thrombolysis), which are not currently available. This paper presents the development of a novel multifunctional FPGA-based pulser/receiver system for intravascular ultrasound imaging and therapy research. The open platform consists of a host PC with a Matlab-based software interface, an FPGA board, and a proprietary analog front-end board with state-of-the-art electronics for highly flexible transmission and reception schemes. The main features of the system include the capability to convert arbitrary waveforms into tristate bipolar pulses by using the PWM technique and by the direct acquisition of raw radiofrequency (RF) echo data. The results of a multicycle excitation pulse applied to a custom 550 kHz therapy transducer for acoustic characterization and a pulse-echo experiment conducted with a high-voltage, short-pulse excitation for a 19.48 MHz transducer are reported. Testing results show that the proposed system can be easily controlled to match the frequency and bandwidth required for different IVUS transducers across a broad class of applications. Full article

Background and aims: Epicardial RFA is often required when ventricular tachyarrhythmias originate from epicardial or subepicardial substrates that cannot be effectively ablated endocardially. Our objective was to evaluate the impact of intrapericardial fluid accumulation on the lesion size in the myocardium and the extent of thermal damage to adjacent structures, particularly the lung. Methods: An in silico model of epicardial RFA was developed, featuring an irrigated-tip catheter placed horizontally on the epicardium. A 50 W–30 s RF pulse was simulated. Temperature distributions and resultant thermal lesions in both the myocardium and lung were computed. Results: An increase in pericardial space from 2.5 mm to 4.5 mm resulted in a reduction of myocardial lesion depth by up to 1 mm, while the volume of lung damage decreased from 200 to 300 mm³ to nearly zero, irrespective of myocardial or epicardial fat thickness. Myocardial lesion size was markedly influenced by the thickness of the epicardial fat layer. In the absence of fat and with a narrow pericardial space, lesions reached up to 262 mm³ in volume and 6.1 mm in depth. With 1 mm of fat, lesion volume decreased to below 100 mm³ and depth to 3 mm; with 2 mm, to under 40 mm³ and 2 mm; and with 3 mm, to less than 16 mm³ and 1.2 mm. Lung damage increased moderately with greater fat thickness. Cooling the irrigation fluid from 37 °C to 5 °C reduced lung damage by up to 51%, while myocardial lesion size decreased by only 15%. Conclusions: Intrapericardial fluid accumulation can limit myocardial lesion formation while protecting adjacent structures. Cooling the irrigation fluid may reduce collateral damage without compromising myocardial lesion depth. Full article

The proliferation of telecommunication devices in recent decades has resulted in a substantial increase in exposure risk to manmade radiofrequency electromagnetic fields (RF-EMFs) for both animals and plants. The physiological effects of these exposures remain to be fully elucidated. In this study, we measured and analyzed the chlorophyll fluorescence rise kinetics of lettuce plants in the presence of RF-EMFs and after a short drought treatment. The analysis of the fluorescence data was conducted using two different strategies: a conventional JIP test and a novel machine learning-assisted anomaly-detection approach. Our results suggest that exposure to RF-EMFs weakens the plant’s hormetic responses induced by drought treatment, both in terms of the response’s magnitude and its extent. These findings provide further evidence supporting the hypothesis that RF-EMFs interfere with plant stress responses. Full article