Single Radio Frequency Research Articles

Impact of pre-ablation left appendage flow velocities on long term recurrence of catheter ablation for paroxysmal atrial fibrillation.

Despite undergoing a single ablation, many patients with paroxysmal atrial fibrillation (PAF) experience a gradually increasing recurrence rate. This study aims to examine the relationship between left atrial appendage emptying velocity (LAAeV) and filling velocity (LAAfV) profiles and 3-year recurrence of AF after ablation. We conducted a prospective study of 658 consecutive PAF patients who underwent their first ablation between January 2018 and December 2019. We collected the clinical and echocardiographic characteristics of the patients. LAAeV and LAAfV were obtained from a transesophageal echocardiogram (TEE) before catheter ablation. Patients were followed at regular intervals to monitor for the primary outcome of AF recurrence. After a median follow-up period of 35.3 months (range, 10.7-36.3), 288 patients (43.8%) experienced AF recurrence after catheter ablation. Patients who experienced AF recurrence had decreased LAAeV and LAAfV (LAAeV: 56.5±21.2vs. 59.6±20.7cm/s, p=.052; LAAfV: 47.5±17.9vs. 51.7±18.2, p=.003). Kaplan-Meier analysis showed that patients in the low LAAeV(<55cm/s) group had a poorer event-free survival rate than those in the high LAAeV (≥55cm/s) group (log-rank p=.012). Patients with LAAfV<48cm/s had a significantly higher risk of AF recurrence than those with LAAfV ≥48cm/s (log-rank p=.003). In the multivariable model, low LAAfV pre-ablation in TEE-guided was significantly independently associated with 3-year recurrence after single radiofrequency ablation in patients with PAF, along with LA dimension and duration of AF. This study found an independent association between low LAAfV pre-ablation in TEE-guided and 3-year recurrence after single radiofrequency ablation in patients with PAF.

1-Bit Programmable Metasurface-Based 2-D Direction Finding

A novel two-dimensional (2-D) direction finding method is proposed, relying on a 1-bit programmable metasurface and the time modulation method. Both the azimuth and elevation angles of far-field signals are estimated simultaneously by analyzing the harmonic characteristic of received signals in the frequency domain. Low hardware cost and computational complexity can be achieved owing to the intrinsic nature of the single radio frequency (RF) chain in the proposed method. Extensive numerical results confirm that the direction finding attains a near-zero mean square error (MSE), when the signal-to-noise ratio (SNR) attains 10 dB. A Ka-band reflective programmable metasurface with 400 elements is fabricated and tested to verify its effectiveness partly.

Optimal Antenna Selection and Beamforming for an IRS Assisted System

An intelligent reflecting surface (IRS) is a cost and energy-efficient solution to improve wireless system performance. Transmit antenna selection (AS) harnesses the benefits of multiple antennas with a smaller number of radio frequency (RF) chains. We focus on joint optimization of antenna subset and transmit beamforming at the transmitter (Tx) and passive beamforming at the IRS to maximize the receive signal power. We derive a closed-form optimal AS rule for a Tx and receiver (Rx) equipped with single RF chain each and ideal IRS. We analyze its performance with a correlated channel model and then extend it to non-ideal IRS. We also propose a simpler rule that significantly reduces the number of computations and pilots. For an Rx that performs maximal ratio combining, we propose a manifold optimization algorithm and a low-complexity selection rule. For a Tx with multiple RF chains, we propose a subset selection algorithm that yields a locally optimal solution and an alternating optimization algorithm that reduces complexity. Our simulations study the impact of estimation errors, discrete phase shifts, and channel correlation on the proposed selection rules, which perform better than the existing AS rules. They also show that the proposed low-complexity rules are near-optimal.

Hybrid Beamforming in Massive MIMO for Next-Generation Communication Technology.

Hybrid beamforming is a viable method for lowering the complexity and expense of massive multiple-input multiple-output systems while achieving high data rates on track with digital beamforming. To this end, the purpose of the research reported in this paper is to assess the effectiveness of the three architectural beamforming techniques (Analog, Digital, and Hybrid beamforming) in massive multiple-input multiple-output systems, especially hybrid beamforming. In hybrid beamforming, the antennas are connected to a single radio frequency chain, unlike digital beamforming, where each antenna has a separate radio frequency chain. The beam formation toward a particular angle depends on the channel state information. Further, massive multiple-input multiple-output is discussed in detail along with the performance parameters like bit error rate, signal-to-noise ratio, achievable sum rate, power consumption in massive multiple-input multiple-output, and energy efficiency. Finally, a comparison has been established between the three beamforming techniques.

A novel method of interference source direction-finding with an existing single antenna beam in communication satellites

Interference has recently become a critical factor in communication satellite performance, and the interference source location is one of the most important factors in resolving this issue. The article proposes an innovative method of interference source direction-finding suitable for communication satellites with an existing single antenna beam and single radio frequency (RF) channel, which utilizes the symmetry of the antenna pattern to search for interference sources. Compared to traditional position methods with time-frequency-synchronized multi-satellites or a directing antenna array in a single satellite, the method does not require any particular direction-finding payload in communication satellites and shares existing antennas and RF channels with communication systems in satellites. The ability to find the direction of the interference source is a software-defined function in the communication processor. The proposed method provides a novel way to solve the problems of interference source direction-finding with the least engineering complexity, and it has excellent coexistence with other existing systems in communication satellites. The computer simulation and out-field experiment results in this article show that the method has excellent performance with high direction-finding resolution within extensive coverage, offering significant value and bright prospects for resolving the growing interference issues in communication satellites.

Spectrally Efficient Pulse Shaping for Beamspace Space Shift Keying in Single-RF ESPAR Systems

A novel spectrally efficient pulse shaping technique for space shift keying (SSK) in single radio frequency (single-RF) antenna systems is proposed. This technique is important since a key issue often overlooked in most single-RF systems, including SSK, is pulse shaping. The proposed pulse shaping technique is based on using an electronically steerable parasitic array radiator (ESPAR). It can avoid the bandwidth expansion arising from switching in SSK while enhancing spectral efficiency (SE) compared to conventional time-limited pulse shaping. In the proposed approach, we pulse shape the parasitic loads of the antennas in the ESPAR by using pulse shaped baseband control voltages to continuously vary the parasitic loads. This is enabled by developing an approximate linear mapping from the baseband control voltages to the ESPAR element currents. Simulation results of the proposed technique are provided, including the continuous-time ESPAR current and its power spectrum density, adjacent channel power ratio, symbol error rate (SER), SE, and energy efficiency (EE). It is shown that the proposed technique can perform spectrally efficient pulse shaping for beamspace SSK and achieve higher SE and EE than time-limited pulse shaping while maintaining the same SER.

Measurements of variable capacitance using single port radio frequency reflectometry

A radio frequency (RF) reflectometry technique is presented to measure device capacitances using a probe station. This technique is used to characterize micro-electromechanical system (MEMS) variable capacitor devices that can be connected to create pull-up and pull-down networks used in digital gates for reversible computing. Adiabatic reversible computing is a promising approach to energy-efficient computing that can dramatically reduce heat dissipation by switching circuits at speeds below their RC time constants, introducing a trade-off between energy and speed. The variable capacitors in this study will be measured using single port RF reflectometry achieved with a custom-made RF probe. The RF probe consists of a micromanipulator with an on-board matching network and is calibrated by measuring a capacitive bank that shows a clearly visible frequency shift with the increase in capacitance. The RF probe worked well when measuring static capacitors with no parasitic resistance; however, the frequency shift is masked when measuring the MEMS variable capacitors due to their high in-series parasitic resistance (around 80 kΩ). Therefore, RF reflectometry has the potential to measure MEMS variable capacitors in the range of 0–30 fF when not masked by a high in-series parasitic resistance, creating a fast and versatile method for characterizing variable capacitors that can be used in energy-efficient computing.

Electrical Modeling of Spin-Torque Diodes Used as Radio Frequency Detectors: A Step-by-Step Methodology for Parameter Extraction

In this article here below, we present an electrical model for nanoscale spintronic radio frequency (RF) detectors called spin-torque diodes (STDs). A complete methodology for model parameter extraction is proposed. An equivalent electrical circuit for STD is derived and includes a modeling of the device resistance nonlinearity together with the STD effect. A detailed step-by-step methodology is presented to extract the model parameters using conventional dc measurements, RF scattering parameters ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S$</tex-math> </inline-formula> -parameters), continuous wave (CW), and power characterizations. After parameter extraction, a comparison with measurements of a single STD successfully validates the model. Finally, the proposed STD electrical model is used to anticipate the behavior of a two-STD-based RF detector architecture. Simulation results highlight the interest of the proposed modeling approach to investigate suitable RF detector architectures to enhance RF-to-dc conversion efficiency for single or multiband RF detection.

Analog Beamforming Using ESPAR for Single-RF Precoding Systems

A novel analog beamforming technique that utilizes single radio frequency (single-RF) electronically steerable parasitic array radiator (ESPAR) antennas is proposed. The ESPAR beamforming techniques are aimed at precoding in multiple antenna wireless communication systems using the single or hybrid RF approach. One advantage of ESPAR analog beamforming compared to conventional analog beamforming using phase shifters is that arbitrary patterns can be straightforwardly formed. Therefore, ESPAR analog beamforming can provide performance almost identical to digital beamforming. More importantly, ESPAR analog beamforming does not require phase shifters and power splitters, overcoming implementation challenges of conventional analog beamforming. It also has a more compact size compared to conventional beamforming using uniform antenna arrays. We analyze and optimize ESPAR analog beamforming and propose a channel approach based on beamspace pilot transmission to acquire channel state information (CSI). In addition, we propose limited feedback ESPAR analog beamforming based on a beamforming selection strategy. Simulation results for average gain show that ESPAR analog beamforming has almost identical performance to digital beamforming and better performance than analog beamforming using phase shifters. Energy efficiency simulations show that the technique has the highest efficiency among all the beamforming techniques. Therefore, ESPAR analog beamforming has near optimal performance, high energy efficiency, low circuit complexity, low cost, compact size and can be an effective alternative to conventional analog beamforming.

AoA-Based Low Complexity Beamforming for Aerial RIS Assisted Communications at mmWaves

Reconfigurable intelligent surface (RIS) mounted on mobile devices (aerial RIS), such as unmanned aerial vehicles, is envisioned to increase coverage for future millimeter wave (mmWave) communications. In literature, RIS beamformer is designed using channel state information (CSI) or by scanning through gNodeB and user codebooks over different training RIS weight matrices. Both of these methods incur significant training overhead. Also, the traditional subspace-based AoA estimators require several power-intensive radio frequency (RF) chains, which is not practically affordable to users. As a low-power and low-complexity alternative, we propose to design RIS beamforming weights based on angle-of-arrival (AoA) from gNodeB-to-RIS and from RIS-to-user with a single RF chain coupled to an antenna array. The proposed estimator is a combination of maximum likelihood and maximum correlation estimator and uses a single RIS training matrix. The simulation results show that, though a slightly larger number of antenna elements is required for the same spectral efficiency, the proposed approach offers a significantly energy- and computationally-efficient beamforming alternative compared to the existing subspace-based AoA estimator and CSI based techniques.

Impact of a standardized pacing protocol on end point verification and first pass isolation using a multipolar pulsed-field ablation catheter for pulmonary vein isolation

Pulsed-field ablation (PFA) has emerged as a novel treatment strategy for patients with atrial fibrillation (AF) ( 1 Badertscher P, Weidlich S, Serban T, et al. Pulsed-field ablation versus single catheter high-power short-duration radiofrequency ablation for atrial fibrillation: procedural characteristics, myocardial injury and midterm outcomes. Heart Rhythm 2023. Google Scholar , 2 Reddy VY, Dukkipati SR, Neuzil P, al. Pulsed Field Ablation of Paroxysmal Atrial Fibrillation: 1-Year Outcomes of IMPULSE, PEFCAT, and PEFCAT II. JACC Clin Electrophysiol 2021; 7(5):614–627. Google Scholar ). In general, acute pulmonary vein isolation (PVI) may be confirmed by entrance and exit block ( 3 Duytschaever M. Meyer G de Acena M. et al. Lessons from dissociated pulmonary vein potentials: entry block implies exit block. Europace. 2013; 15: 805-812 Crossref PubMed Scopus (25) Google Scholar ). The penta-spline PFA catheter only provides larger electrodes and wider inter-electrode distance making such an assessment less reliable. Little is known about the required number of applications when using PFA as systematically assessed via exit block testing. Likewise, since close proximity of the PFA catheter to the PV ostium seems to be of importance ( 2 Reddy VY, Dukkipati SR, Neuzil P, al. Pulsed Field Ablation of Paroxysmal Atrial Fibrillation: 1-Year Outcomes of IMPULSE, PEFCAT, and PEFCAT II. JACC Clin Electrophysiol 2021; 7(5):614–627. Google Scholar ), catheter positioning might be optimized by pacing before the first PFA application and adjusting contact depending on the ability to capture atrial myocardium. Thus, our aim was to assess the number of PFA applications per PV until acute PVI was observed and to assess the impact of a standardized pacing protocol on first pass isolation (FPI) confirmed via electroanatomical mapping (EAM). We prospectively enrolled consecutive patients undergoing their first PVI. In brief, the PFA 31 mm Farawave© catheter (Boston Scientific, Marlborough, MA) was inserted into the left atrium via a single transseptal puncture. PVI was performed as described previously ( 2 Reddy VY, Dukkipati SR, Neuzil P, al. Pulsed Field Ablation of Paroxysmal Atrial Fibrillation: 1-Year Outcomes of IMPULSE, PEFCAT, and PEFCAT II. JACC Clin Electrophysiol 2021; 7(5):614–627. Google Scholar ). In group 1 no standardized pacing protocol was applied prior or after PVI. In group 2, pacing was performed prior to the first application across all five bipoles to assess proximity of the PFA catheter to the PV ostium. Entrance and exit block were then assessed after each PFA application per PV separately. PVI was subsequently confirmed via EAM. The study was approved by the local ethics committees and adhered to the Helsinki Declaration.

Pulsed-field ablation versus single catheter high-power short-duration radiofrequency ablation for atrial fibrillation: procedural characteristics, myocardial injury and midterm outcomes

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulsed-field ablation (PFA) has emerged as a novel treatment strategy for patients with atrial fibrillation (AF). A direct comparison to high-power short-duration (HPSD) radiofrequency (RF) ablation using a single catheter is lacking. Aim To compare pulmonary vein isolation (PVI) using PFA versus single catheter HPSD-RF ablation regarding efficiency, safety, myocardial injury, and outcomes. Methods 119 patients underwent PVI and were included (age 65.6 ± 10 years, ejection fraction 0.55 ± 0.11, left atrial size 41 ± 6.6 mm, paroxysmal AF 55%). 56 patients (47%) underwent PFA using a multi-electrode pentaspline PFA catheter with a biphasic waveform and 63 patients (53%) underwent single catheter HPSD-RF ablation without a multipolar mapping catheter. Results Using PFA the median procedure time was significantly shorter compared to the single catheter HPSD-RF group with 58 (IQR 51-70) min versus 83 (IQR 71-99) min (p&amp;lt;0.001), while fluoroscopic time was significantly longer with 12 (IQR 10-16) min versus 2.2 (IQR 1.3-3.6) min (p&amp;lt;0.001). First-pass isolation was achieved in 91% of the PFA group and 88% in the HPSD-RF group. 3.3 catheters vs. 1.0 catheters were used in the PFA group versus the HPSD-RF group, p&amp;lt;0.01. One procedural complications was observed in the PFA group and one complication in the HPSD-RF group (Tamponades). High sensitivity cardiac troponin levels were on average significantly higher in patients using the PFA system, 1520 (IQR 1010-1980) ng/l compared to 897 (IQR 725-1240) ng/l in the HPSD-RF group. During a median follow-up of 177 days (IQR 92-300), AF recurrence was observed in five patients (9%) from the PFA group and in 15 patients (24%) from the HPSD-RF group. (Figure 1) Conclusion PFA showed shorter procedure times but longer fluoroscopy times, higher levels of hs cTnT, and a possible improved AF-free survival.

Photo-responsive Zinc Oxide-coated alumina ceramic membrane with super-wettable and self-cleaning features fabricated by single step RF magnetron sputtering for oily water treatment

Zinc Oxide (ZnO) coated alumina ceramic membrane with super-wettable and photo-responsive self-cleaning features was fabricated by radio frequency (RF) magnetic sputtering, and used as a filtering medium in the dead-end filtration system for oily water treatment. The chemistry of the material in conjunction with the optimum surface roughness accomplish by RF magnetic sputtering rendered a unique surface wettability, favorable for water passing oil-in-water emulsion separation. The second desirable functionality of the membrane is its self-cleaning potential under light irradiation, owing to the efficient photo-catalytic property of ZnO. Oil-surface-air and water-surface-air interfacial contact angles for the membrane surface were measured using goniometer and they are close to 0° (superhydrophilic / superoleophillic in air), whereas under the water oil-surface-water interfacial contact angle switched to 158.70° (underwater superoleophobic). The oil-in-water emulsion separation efficiency, the water permeate flux were measured at different trans-membrane pressures, and oil concentrations in oily water emulsion, and the results showed that 99.9% oil-in-water emulsion separation efficiency was maintained for a range of trans-membrane pressure, and oil concentration for a long duration of use. The highest permeate flux rate and separation efficiency (%) of the fabricated Zinc oxide-coated alumina ceramic membrane were found to be ∼325 L/m2.h and 99.9%, respectively at 2 bar using surfactant stabilized oil-in-water emulsions as feed. However, the water flux declined with reduced trans-membrane pressure, increased oil concentration and with the long use of the membrane. The advantage of ZnO-coated alumina ceramic membrane is that it is water passing, and hence the oil clogging of the membrane is quite minimal. However, with the long use the membrane is prone to the deposition of oily contaminant on the membrane surface, which resulted in low water permeate flux, and this problem was resolved, and the original permeate flux was restored by routine self-cleaning of the membrane surface by illuminating light on the photo-catalytic ZnO film on the membrane surface. In addition to the wettability studies of the membrane, the structural, chemical and morphological characterizations of the material, and the coated membrane were carried out.

AB-452663-2 LEFT ATRIAL BOX ISOLATION GUIDED BY FORCE-POWER-TIME FORMULA (ABLATION INDEX): HIGH PREVALENCE OF EPICARDIAL CONDUCTION VIA SEPTOPULMONARY BUNDLE IN ATRIAL FIBRILLATION PATIENTS

Circumferential, continuous, transmural atrial lesions are desired to facilitate pulmonary vein (PV) isolation. However, atrial wall thickness around the PV is variable (5-6 mm in the superior/anterior segments and 2-4 mm in the inferior/posterior segments). Previous experimental studies have shown that radiofrequency (RF) lesion depth and diameter can be predicted by a logarithmic formula using contact force (CF), RF power and application time (Force-Power-Time Formula, Ablation Index, AI). The purpose of this study was to test the ability of AI guided ablation to achieve left atrial (LA) box isolation by a single RF encirclement and examine the location of residual conduction (gap) within the box in patients with atrial fibrillation (AF). In 42 patients with AF, LA box isolation was performed using a 7.5Fr CF catheter (ThermoCool SmartTouch SF, Biosense Webster) and CARTO system. Using RF power (35-40Watts) and CF (5-45g), a target AI value of 380-400 was used for posterior/inferior segments with an inter-lesion distance (ILD) of 4mm and a target AI value of 550-600 for anterior/superior/septal segments with an ILD of 6mm along the box circumference (Figure). RF was delivered until AI reached target values or terminated prematurely when esophageal temperature reached <38.5°C. After the first encirclement along the box line, activation mapping was performed to confirm box isolation and identify gap locations. Total RF time for box isolation was 27.2±4.6 min and box circumference length was 21.2±2.5 cm. Complete box isolation was obtained by the first encirclement in 17/42 (40%) pts. In the remaining 25/42 (60%) pts, activation mapping within the box lesion set identified earliest atrial activation along the ablation line in only 4/42 (10%) pts (indicating endocardial gaps), whereas activation mapping within the box identified earliest atrial activation at a site distant from the ablation line in 21/42 (50%) pts, suggesting epicardial conduction through a septopulmonary bundle (Figure). Focal ablation at endocardial gaps along the ablation line or at the epicardial focal breakouts within the box resulted in compete box isolation in all 25 pts. LA box isolation guided by AI effectively prevented endocardial gaps along the ablation line. However, epicardial conduction via a septopulmonary bundle was often observed (50%).

The Reconfigurable Intelligent Surface-Aided Multi-Node IoT Downlink: Beamforming Design and Performance Analysis

Reconfigurable intelligent surfaces (RISs) are capable of enhancing the wireless propagation environment of the future Internet of Things (IoT). Recently, they have also been configured as a transmitter to realize information modulation at low hardware complexity. In this article, we conceive a transmitter relying on a single radio frequency (RF) chain for low-complexity RIS-aided multiuser downlink communication. More explicitly, in the proposed architecture, the multiuser information is transmit precoded and modulated at the RIS by appropriately configuring the phase shift and amplitude of each RIS element. We assume that the distribution of multiple users obeys on a Poisson point process (PPP), where we jointly optimize the total power reflected from the RIS and the power allocation fraction assigned to each user, under the practical constraint of a realistic amplitude limitation of each RIS element. Additionally, we theoretically analyze the ergodic rate, symbol error probability, outage probability, and coverage range of the proposed RIS-aided single-RF downlink and confirm the accuracy of our analysis by simulations. Finally, we compare its performance to that of the conventional multiple-input-multiple-output (MIMO) systems employing multiple RF-chains.

High efficiency radio frequency antennas for amplifier free quantum sensing applications

Radio frequency (RF) signals are frequently used in emerging quantum applications due to their spin state manipulation capability. Efficient coupling of RF signals into a particular quantum system requires the utilization of carefully designed and fabricated antennas. Nitrogen vacancy (NV) defects in diamond are commonly utilized platforms in quantum sensing experiments with the optically detected magnetic resonance (ODMR) method, where an RF antenna is an essential element. We report on the design and fabrication of high efficiency coplanar RF antennas for quantum sensing applications. Single and double ring coplanar RF antennas were designed with −37 dB experimental return loss at 2.87 GHz, the zero-field splitting frequency of the negatively charged NV defect in diamond. The efficiency of both antennas was demonstrated in magnetic field sensing experiments with NV color centers in diamond. An RF amplifier was not needed, and the 0 dB output of a standard RF signal generator was adequate to run the ODMR experiments due to the high efficiency of the RF antennas.

Joint RIS Grouping Design Assisted Generalized Quadrature Reflection Modulation

In this paper, a novel joint reconfigurable intelligent surface (RIS) grouping design assisted generalized quadrature reflection modulation (JGD-GQRM) scheme is proposed for a single radio frequency (RF) multiple-input multiple-output (MIMO) system. In JGD-GQRM, a limited number of RIS elements are spatially grouped, and the remaining reflection patterns are utilized for joint mapping to improve the reliability of the transmission. Moreover, it maps additional information bits by full reflection passive beamforming to improve the system's spectral efficiency (SE). In addition to the optimal maximum likelihood (ML) detector that has high computational complexity, a low-complexity sequential greedy detection (SGD) for JGD-GQRM is proposed. Simulation results show that the proposed scheme can achieve better bit error rate (BER) performance than the existing reflection modulation.

A robust cascaded deep neural network for image reconstruction of single plane wave ultrasound RF data

Reconstruction of ultrasound data from single plane wave Radio Frequency (RF) data is a challenging task. The traditional Delay and Sum (DAS) method produces an image with low resolution and contrast, if employed with RF data from only a single plane wave. A Coherent Compounding (CC) method that reconstructs the image by coherently summing the individual DAS images was proposed to enhance the image quality. However, CC relies on a large number of plane waves to accurately sum the individual DAS images, hence it produces high quality images but with low frame rate that may not be suitable for time-demanding applications. Therefore, there is a need for a method that can create a high quality image with higher frame rates. Furthermore, the method needs to be robust against the input transmission angle of the plane wave. To reduce the method’s dependence on the input angle, we propose to unify the RF data at different angles by learning a linear data transformation from different angled data to a common, 0° data. We further propose a cascade of two independent neural networks to reconstruct an image, similar in quality to CC, by making use of a single plane wave. The first network, denoted as “PixelNet”, is a fully Convolutional Neural Network (CNN) which takes in the transformed time-delayed RF data as input. PixelNet learns optimal pixel weights that get element-wise multiplied with the single angle DAS image. The second network is a conditional Generative Adversarial Network (cGAN) which is used to further enhance the image quality. Our networks were trained on the publicly available PICMUS and CPWC datasets and evaluated on a completely separate, CUBDL dataset obtained from different acquisition settings than the training dataset. The results thus obtained on the testing dataset, demonstrate the networks’ ability to generalize well on unseen data, with frame rates better than the CC method. This paves the way for applications that require high-quality images reconstructed at higher frame rates.

Safety, tolerability and short-term efficacy of transvaginal fractional bipolar radiofrequency therapy for symptoms of stress and or mixed incontinence in conjunction with genitourinary syndrome of menopause.

Radiofrequency (RF) energy application stimulates collagen and elastin remodeling to restore the elasticity, and moisture of the superficial vaginal mucosa. This is the first study to report on the use of microneedling to deliver RF energy to the vaginal canal. Microneedling increases the response of the collagen contraction and neocollagenesis in deeper layers of tissue, thus increasing the support to the surface. The novel intravaginal microneedling device used in this study allows penetration of the needles to 1, 2, or 3 mm. A prospective study to evaluate the safety and short-term outcome of a single fractional RF treatment of the vaginal canal in a series of women with coexistent stress or mixed incontinence (MUI) and genitourinary syndrome of menopause (GSM). Twenty women who had symptoms of SUI and or MUI in conjunction with GSM were given a single vaginal treatment that consisted of fractional bipolar RF energy using the EmpowerRF platform with the Morpheus8V applicator (InMode). RF energy was delivered into the vaginal walls via 24 microneedles, at a depth of 1, 2, and 3 mm. Outcomes were evaluated by "cough" stress test, questionnaires (MESA SI, MESA UI, iQoL, UDI-6) and evaluation of vaginal tissue through the VHI scale at 1-, 3-, and 6-months post-treatment compared to baseline. Biopsies were performed at baseline and 3-months on five patients for histological reference and tissue evaluation. Eight out of eight outcomes measured from baseline to 6-months post-treatment showed improvement. The parameters scored in the questionnaires including frequency, urgency, nocturia, urge incontinence, and stress incontinence showed significant improvement in all areas at the 1-, 3-, and 6-month follow-up sessions compared to baseline. The results showed evidence that fractional RF energy delivered vaginally is safe, well tolerated, and provide short term improvement of SUI and or MUI in conjunction with GSM.

Persistent dynamics in coupled non-degenerate parametric oscillators: pump saturation prevents mode competition.

The coherent dynamics in networks of coupled oscillators is of great interest in wave-physics since the coupling produces various dynamical effects, such as coherent energy exchange (beats) between the oscillators. However, it is common wisdom that these coherent dynamics are transients that quickly decay in active oscillators (e.g. lasers) since pump saturation causes mode competition that results, for homogeneous gain, in the prevalence of the single winning mode. We observe that pump saturation in coupled parametric oscillators counter-intuitively encourages the multi-mode dynamics of beating and indefinitely preserves it, despite the existence of mode competition. We explore in detail the coherent dynamics of a pair of coupled parametric oscillators with a shared pump and arbitrary coupling in a radio frequency (RF) experiment, as well as in simulation. Specifically, we realize two parametric oscillators as different frequency-modes of a single RF cavity and couple them arbitrarily using a digital high-bandwidth FPGA. We observe persistent coherent beats that are maintained at any pump level, even high above the threshold. The simulation highlights how the interplay of pump depletion between the two oscillators prevents them from synchronizing, even when the oscillation is deeply saturated.