Acute e chronic feasibility of left atrial appendage isolation focal ablation catheter toggling between radiofrequency and pulsed field energy

Quantum simulation aims to recreate complex many-body phenomena in controlled environments, offering insights into dynamics that are otherwise difficult to model. Existing platforms, however, are often complex and costly to scale, typically requiring ultrapure vacuum or low temperatures. Here, we introduce a platform based on a thin, strongly interacting C 13 nuclear spin layer in diamond that allows controlled exploration of many-body dynamics at room temperature. Nearby nitrogen-vacancy centers enable polarization, readout, and, combined with radio-frequency fields, coherent control of the nuclear spins. We demonstrate strong, tunable interactions among the nuclear spins and use the system to probe discrete time-crystalline order across varying interaction ranges. By combining ease of use with operation at ambient temperatures, our work opens new opportunities for investigating strongly correlated many-body effects.

Metallized, 3D-printed radiofrequency coils.

The implementation of electron spin resonance in scanning tunneling microscopy (ESR-STM) represented a milestone in controlling spin systems at atomic scales. To drive spin resonance, a radio-frequency (RF) magnetic field is required. Yet, so far, in ESR-STM, instead of an RF magnetic field an RF electric field has been used for driving, which translates into an effective RF magnetic field. For cases in which such a field-conversion mechanism is not feasible, we developed an implementation of a low-GHz RF magnetic field in a scanning-probe setup. To this end, we utilized a single-loop coil based on a flexible polyimide printed-circuit-board to generate the RF magnetic field. To locally enhance the RF magnetic field in the scanning-probe junction, we used a gold-microstrip on an insulating support as a sample surface. We found that up to 3GHz, the transmission only moderately depends on frequency and exhibits no sharp resonances. This development enabled the implementation of ESR in atomic force microscopy, as was demonstrated for individual pentacene molecules.

Numerical simulations can be adopted to aid the evaluation of the interaction between switched gradient fields and metallic implants and estimate the possible temperature increase. Anyway, an analysis of the consistency of their prediction with experiments is lacking, differently from what can be found for exposure to radiofrequency fields. The purpose of this work is to fill this gap. A systematic comparison between experiments and simulations was conducted, considering commercial metallic orthopedic implants. The complexity of the exposure scenario was gradually increased, starting from the conditions defined in the ISO/TS 10974:2018 standard and moving to more realistic exposure scenarios with sinusoidal or pulsed gradient fields. The computational tools demonstrated an overall good capability in predicting the outcomes of the experimental tests, as long as numerical simulations are properly set up (building of the virtual model, discretization parameters, positioning/orientation of the object). The consistency between simulations and measurements is comparable with the one obtainable under radiofrequency exposure and decreases with exposure complexity. The results pave the way for the use of numerical simulations to support laboratory testing of passive implants heating under time-varying gradient fields.

How anthropogenic electromagnetic noise can affect living systems is a poorly understood impact of an increasingly urbanized natural environment, especially when occurring in a sublethal manner. In this study, we investigated impacts of weak-broadband radiofrequency (RF) fields on animal behavior. We exposed migratory soprano pipistrelle bats (Pipistrellus pygmaeus) to 0.01- to 300-megahertz RF fields and then tested their orientation later in the night. Whereas control bats oriented normally, bats exposed to RF noise exhibited random departure flight orientation, suggesting disruptive effects lasting beyond immediate exposure. These findings suggest that electromagnetic pollution has the potential to have a greater effect on animal behavior than previously assumed.

Neuroinflammation plays a crucial role in various central nervous system (CNS) disorders. This study aims to investigate the potential neuroprotective effects of radiofrequency electromagnetic fields (RF-EMF) and pulsed magnetic fields (PMF) on oxidative stress, apoptosis, and neuroinflammation in lipopolysaccharide (LPS)-induced acute neuroinflammation model in rats. Forty female Wistar Albino rats were randomly assigned to five groups (Control, LPS, LPS + PMF, LPS + RF-EMF, and LPS + RF-EMF + PMF). Acute neuroinflammation was induced by intraperitoneal LPS administration. Rats were subsequently exposed to radiofrequency electromagnetic fields and/or pulsed magnetic fields under controlled conditions. Neuroinflammatory damage was evaluated by histopathological and immunohistochemical analyses targeting apoptosis, inflammation, and myelin integrity. Oxidative stress status was assessed spectrophotometrically, and key genes related to cell survival and neurovascular regulation were analyzed using RT-qPCR. LPS administration induced pronounced neuroinflammation, characterized by histopathological damage, increased apoptotic and inflammatory marker expression, myelin loss, oxidative stress, and suppression of survival- and angiogenesis-related genes. RF-EMF and PMF treatments significantly alleviated these alterations by reducing tissue injury, apoptosis, inflammation, and oxidative stress while restoring myelin integrity. Moreover, RF-EMF and PMF markedly upregulated phosphoinositide 3-kinase/ protein kinase B alpha/ hypoxia-inducible factor 1 alpha signaling and enhanced endothelial nitric oxide synthase and vascular endothelial growth factor expression, indicating improved neurovascular regulation. The combined RF-EMF + PMF therapy produced the most robust protective effects across all evaluated parameters. RF-EMF and/or PMF treatment has features approved by the World Health Organization exerts significant neuroprotective effects by reducing oxidative stress, apoptosis, and neuroinflammation while enhancing cell survival and neurovascular function. The combination of RF-EMF and PMF yielded the most pronounced effects, suggesting that electromagnetic field-based therapies may offer a promising approach for treating neuroinflammation-associated disorders.

Amplitude-modulated radiofrequency (AMRF) fields have emerged as promising non-temperature-induced strategies in oncology. While conventional hyperthermia (HT) relies on thermal stress, the biological impact of AMRF, particularly in combination with radiotherapy (RT), remains insufficiently characterized. We assessed RF and AMRF, alone or with RT, using phenotypic analyses of proliferation, apoptosis, and necrosis across four cancer cell lines (HT29, SW620, U343, U138). Transcriptomic profiling with Kyoto Encyclopedia of Genes and Genomes (KEGG), GO:BP, and Reactome enrichment was performed in SW620 and U138 cells, selected for their strong phenotypic responses. Across the panel, AMRF was associated with broader cytotoxic responses than RF or HT in most but not all cell lines. AMRF+RT produced the strongest necrotic responses, with cell-line-specific exceptions identified explicitly in the Results (the absence of a significant AMRF+RT apoptotic effect in SW620 and the absence of a significant AMRF+RT necrotic response in U343). In SW620 cells, AMRF was associated with extensive transcriptional reprogramming involving immune modulation, extracellular matrix remodeling, and cell cycle regulation, whereas RF alone showed narrower and delayed effects. In contrast, U138 cells showed elevated apoptosis and necrosis but limited transcriptional changes-a phenotype-transcriptome divergence that points to mechanisms operating downstream of transcription and warrants functional investigation in dedicated follow-up studies. AMRF and AMRF+RT emerge as promising non-temperature-induced anticancer modalities in the cell-line models profiled here, with the pattern of response varying between cell lines. These findings expand the biological impact of RF-based treatments and set the grounds for further investigation in mechanistic and translational studies.

Lattice-tip catheter for septal ventricular tachycardia ablation guided by preprocedural imaging.

The problem of spatially selective radio-frequency (RF) pulse design in magnetic resonance imaging (MRI) is typically stated in the form of determining, analytically or numerically, RF waveforms to be applied in synchrony with one or more predetermined gradient waveforms. In most cases, the dynamics of the nuclear spin magnetization under the RF and gradient fields is described in a global rotating frame that cancels the effect of the static (main) magnetic field B0. In this work, we consider an alternative frame of reference, which can be called a local rotating frame where total longitudinal magnetic field (B0 plus gradient) in every voxel is zero. In this frame, the effect of time-dependent gradient field is integrated out, and the remaining magnetization dynamics, governed by much weaker RF fields, becomes both simpler and slower. We show that recasting existing RF design methods in such a frame provides useful insights and techniques that are not obvious in the conventional description. The methods we consider include (i) two-dimensional spatial RF pulse design in the excitation k-space, (ii) Shinnar-Le Roux RF pulse design, (iii) residual phase calculation in slice-selective excitation, and (iv) iterative and numerical solutions for multi-coil RF pulse design. In particular, we show that the new formalism can substantially reduce the Bloch simulation time which can greatly benefit iterative pulse design in parallel transmit. In all, the proposed framework provides considerable theoretical insights and practical utility for RF pulse design in MRI.

We present a mechanism for self-induced Floquet states involving acoustic and optical modes in synthetic antiferromagnets. By driving optical modes off-resonantly with radio frequency fields in the canted antiferromagnetic state, limit cycles arising from the predator-prey dynamics of the acoustic and optical mode populations can appear. The cyclic growth and decay of these mode populations induce a time-periodic modulation of the canted state, which subsequently generates Floquet states. These states appear as a rich frequency comb in the power spectrum of magnetization oscillations.

The redox mechanisms of RAW 264.7 macrophages exposed to 2.45 GHz RF-EMF at subthermal specific absorption rates and to lipopolysaccharide (LPS) and/or the SARS-CoV-2 spike protein (CSP) were investigated. To this end, cellular responses (lysosomal and mitochondrial activity, nitric oxide (NO) production, and cell survival/death) were measured after 6, 24, and 48 h. Selective loss of viability in cells exposed to RF and LPS was observed at 6 h, consistent with early defects in membrane permeability. Lysosomal activity was significantly enhanced in cells treated with RF + LPS. Mitochondrial activity decreased in cells exposed to RF + LPS at 6 h and increased in cells treated with RF + CPS/LPS. Cell viability decreased greatly in cells treated with LPS and CSP + LPS after 24, particularly after 48 h. Nitrite levels peaked in non-irradiated cells treated with RF + LPS and in CSP + LPS at 24 h and decreased in irradiated cells after 48 h. Irradiation affected selection of the death mode: apoptosis decreased or remained unchanged in cells subjected to any of the treatments, while necrosis increased in cells treated with CPS, LPS, or both for 48 h. The combination of RF-EMF and infectious agents reprogrammed the interaction between mitochondria/lysosomes/nitric oxide (NO)/cell death in macrophages in a time- and stimulus-dependent manner.

The characterization of hydrated polysaccharide assemblies by solid-state NMR (ssNMR) remains challenging because hydration modifies proton networks, molecular mobility, and polarization transfer pathways. In this study, we investigate how key experimental parameters-static magnetic field (B0), radiofrequency field strength (B1), magic-angle spinning (MAS) frequency, and cross-polarization (CP) ramp conditions-affect the polarization transfer and proton-mediated spin diffusion in cellulose samples with different hydration states. Using comparative measurements on dry and hydrated cellulose, we analyze how these parameters influence CP efficiency and kinetics, signal intensity, and the spin-diffusion values. The results show that experimental conditions strongly affect the values associated with the proton-driven polarization transfer pathways in hydrated systems. In particular, variations in MAS frequency and RF matching conditions modify the relative contribution of different spin-dynamic processes (THHa, THHb and THHc). The reduced heterogeneity gained at higher magnetic fields results in changes in CP conditions that makes challenging the determination of NMR observables (spin-diffusion and relaxation times). These findings, that cannot be directly assigned to a modification of the underlying molecular dynamics, highlight the importance of carefully optimizing ssNMR experimental conditions when studying hydrated polysaccharide materials. The present work demonstrates how hydration-dependent proton environments influence polarization transfer behavior and the resulting spectroscopic observables. This work provides practical guidance for the design of ssNMR experiments aimed at investigating hydrated cellulose and related biopolymer systems.

Data on premature ventricular complex (PVC) burden after pulmonary vein isolation (PVI) for atrial fibrillation (AF) are inconsistent and often limited to selected populations. We retrospectively analyzed patients undergoing successful first-time PVI for paroxysmal or persistent AF between January 2019 and June 2023. PVC burden was quantified by long-term ECG at baseline, 3months, and 12months. Ablation energy sources included cryoballoon, radiofrequency, and pulsed field ablation. Among 1,069 patients, median PVC burden decreased from 6.82/h at baseline to 1.44/h at 3months and 3.75/h at 12months. In patients with complete follow-up (n = 165), PVC burden declined significantly overall (Friedman test p < 0.001). Post-hoc analyses confirmed reductions from baseline to 3 and 12months, with a modest increase between 3 and 12months (all p < 0.01). PVC burden was similar regardless of AF recurrence or ablation energy. At 12months, 4.6% of patients had high PVC burden (> 5%). Diabetes mellitus (OR = 4.43; 95% CI: 1.49-13.17; p = 0.007) and reduced left ventricular ejection fraction (OR = 6.36; 95% CI: 2.03-19.91; p = 0.002) were independently associated with elevated burden, while other covariates were not significant. PVI significantly reduces PVC burden in most patients, independent of AF recurrence or ablation modality. Diabetes and impaired ventricular function identify patients at risk of persistent high PVC burden. PVI may particularly benefit AF patients with symptomatic PVCs, but larger prospective studies are needed to validate these findings and assess clinical outcomes.

The biological function of proteins is often driven by "invisible" excited states-transient, low-population conformations that remain undetectable by conventional structural methods. Chemical Exchange Saturation Transfer (CEST) NMR spectroscopy is a powerful technique for characterizing these states; however, the complexity of data analysis and the computational cost of numerical fitting have hindered its widespread adoption. To address these challenges, we present ONEST (Optimized Novel Exchange Saturation Transfer), a user-friendly web server designed to automate and accelerate CEST analysis. ONEST utilizes a simultaneous multi-field fitting algorithm that leverages exact analytical solutions for two-state exchange (Baldwin model) rather than computationally intensive numerical integration. This approach incorporates a rigorous correction for radio-frequency (RF) field inhomogeneity and resolves parameter degeneracy by jointly fitting datasets acquired at distinct RF field strengths. Validation against synthetic datasets yielded reduced c2 values near unity (∼1.05), confirming that the analytical approach recovers kinetic parameters with accuracy comparable to full Bloch-McConnell simulations but at a fraction of the computational cost. Furthermore, application to the anti-HIV lectin OAA successfully characterized slow conformational exchange (kex = 279 s-1) involving a minor population of 3%. By streamlining the extraction of kinetic and thermodynamic parameters, ONEST significantly lowers the technical barrier to entry, enabling a broader range of researchers to investigate protein dynamics at atomic resolution. dlee04@kbsi.re.kr. ONEST is available through the web server at http://onest.ai.kr.

A modification ofthe widely used spin-lock-induced crossing (SLIC)procedure is proposed for the solution nuclear magnetic resonance(NMR) of strongly coupled nuclear spin systems, including singletNMR and parahydrogen-enhanced hyperpolarized NMR experiments. Thecompensated-SLIC (cSLIC) scheme uses a repetitive sequence where therepeated element employs two different radio-frequency field amplitudes.Effective compensation for deviations in the radio-frequency fieldamplitude is achieved without increasing the overall duration of theSLIC sequence. The advantageous properties of cSLIC are demonstratedby numerical simulations and representative experiments.

The systematic review by Mevissen et al. (2025, Environment International) evaluated the evidence on the carcinogenicity of radiofrequency electromagnetic fields (RF-EMF) in laboratory animals and concluded with a high certainty of evidence (CoE) that exposure to RF-EMF increases the risk of malignant glioma and malignant schwannoma in the brain and heart, respectively. Deviating from their pre-published systematic review protocol, the authors did not perform meta-analyses. Instead, they based their assessment on whether or not statistically significant increases in tumour rates were observed in the included studies. One positive finding was deemed sufficient to conclude an adverse effect of RF-EMF exposure in a specific organ, thereby setting the target of the CoE rating for that organ. Here, we question this approach because it does not consider all the available evidence, and highlight further methodologically inconsistent decisions, while laying out a quantitative alternative based on the protocol and common guidelines for systematic reviews. Re-assessing the eligible long-term carcinogenicity experiments, we consider important studies to be sufficiently similar to be combined in a meta-analysis (MA). We calculate odds ratios as the effect measure and perform MA as well as dose-response MA. Rating the results using GRADE and OHAT guidance, we downgrade the CoE for imprecision due to the very wide confidence intervals of the pooled odds ratios, and upgrade the CoE for malignant heart schwannomas because of a positive exposure-response association, concluding moderate and low CoE for carcinogenicity of RF-EMF exposures in the heart and brain, respectively. In summary, our quantitative assessment of the evidence results in lower CoE conclusions than those of Mevissen et al.

The electron cyclotron resonance ion plasma accelerator (ECRIPAC) is an original accelerator concept proposed in the 1990s for the generation of highly energetic pulsed ion beams, suitable for a wide array of applications. The initial studies on the subject were characterized by an important calculation mistake, leading to incomplete and erroneous literature on the topic. Nevertheless, the simple and well-mastered techniques involved in the system (radio frequency and magnetic field), together with the device compactness, are strong motivations for further studies on the ECRIPAC. This Letter proposes a comprehensive introduction to ECRIPAC physics, including a summary of its corrected theory. The designs of several compact demonstrator devices, able to accelerate different ion species to energies up to 100 MeV, are presented. Particular focus is devoted to a He^{2+} accelerator, capable of generating 9.5-MeV/nucleon ions inside a 1.8-m-long accelerating cavity. This device has been simulated using a Monte Carlo (MC) code, developed to model the electron dynamics inside this system. The MC results show excellent agreement with the updated theory, which validates the new theoretical framework of the ECRIPAC. Finally, some estimations for the beam parameters of the ion bunch extracted from the accelerator are provided.

Rydberg atom radio frequency sensors are unique in a number of ways, including possessing extraordinary carrier bandwidth, self-calibration, and accuracy. In this Letter, we examine the impact of thermal radiation on Rydberg atom sensors. Antennas are limited by their thermal background, while Rydberg atom sensors are coherent sensors. Incoherent thermal radiation does not limit Rydberg atom sensors in the same way as an antenna. The primary consequence of a thermal radiation field on Rydberg atom sensors is to decrease their coherence, as the decay rates of the Rydberg states used for sensing the radio frequency field are increased due to the thermal field, i.e., blackbody, modification of the atomic decay rates. Thermal and coherent field excitation are fundamentally different in that thermal fields produce statistically independent excitations with well-defined frequency, polarization, and propagation direction, while coherent states are coherent superpositions of photon number states. Consequently, thermal fields do not contribute to the coherences of the density matrix that are used for Rydberg atom sensing, except for damping them.

Control over plasmonic properties and local electric field enhancement has become an essential aspect of many modern technologies. Here we investigate these phenomena in graphene / hexagonal boron nitride (G/h-BN) heterostructures positioned on silicon (Si) and silicon dioxide (SiO2) substrates. Using finite element method for physics-based simulations of radio-frequency (RF) fields in optical range, we analyze electric field at the edges, on the flakes, and in the surrounding regions of the G/h-BN heterostructures. The results demonstrate that the electric field distribution around and within the heterostructure is strongly dependent on the thickness of graphene and h-BN flakes. The highest electric field amplification and focusing occurs at the G/h-BN edge for h-BN thicknesses between 80 and 100 nm on the Si substrate. In contrast, the SiO2 substrate substantially reduces overall field intensity in the G/h-BN heterostructures in comparison to the Si and reference structure without h-BN. These findings provide a consistent theoretical explanation for previously reported experimental Raman spectroscopy data on G/h-BN heterostructures and corroborate the model of localized charge carrier accumulation at the nanoscale G/h-BN edges on Si substrates. Furthermore, the study provides predictions for optimal excitation frequencies and for tailoring graphene plasmonic features in visible spectral range with the use of diamond and other CMOS compatible materials.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-026-40039-y.