Circular Mapping Research Articles

Single versus double transseptal puncture for pulmonary vein isolation with radiofrequency catheter ablation for atrial fibrillation - insights from "Go for Zero Fluoroscopy" registry

Abstract Background Transseptal puncture is one of the most challenging steps in catheter ablation of atrial fibrillation (AF) because of the potential risk of complication. While single TSP reduces the puncture-related risk, double TSP simplifies the procedure (immediate signal visualization in pulmonary veins, avoidance of multiple changes of catheters through the single sheath). The purpose of this study was to analyze the impact of single versus double TSP during pulmonary vein isolation (PVI) with radiofrequency (RF) catheter ablation for AF on the fluoroscopy usage and procedure time. Methods Data reported from the international, multicenter prospective „Go For Zero Fluoroscopy Registry" performed in years 2018–2019 were analyzed. Overall 25 European electrophysiology centers from 14 countries and up to 5 operators from each center were enrolled. Only isolated PVI procedures were analyzed. Results A total data of 393 PVI RF procedures were collected from 25 centers. The median dose-area-product (DAP), fluoroscopy time and overall procedure time were: 810 (325 – 1839) cGy*cm2, 8 (4 – 14) minutes and 124 (92 – 168) minutes, respectively. Single TSP was associated with significantly higher DAP: 984 (459 – 1939) vs 667 (227 – 1469) cGy*cm2 (p=0.002), longer fluoroscopy time: 11 (6 – 19) vs 6 (3 – 11) minutes (p<0.001) and longer overall procedure time: 133 (103 – 168) vs 110 (90 – 168) minutes (p=0.003) as compared with double TSP. Single and double TSP group did not differ significantly in regards of general anesthesia usage, circular and multipolar mapping catheter use (p>0.05). However, single TSP was performed by operators with longer EP lab experience: 10 (4 – 15) vs 3 (0 – 10) years (p<0,001). Conclusions Double TSP is related with lower fluoroscopy usage and shorter overall procedure time of pulmonary vein isolation with radiofrequency catheter ablation for atrial fibrillation.

HD grid versus circular mapping catheter for assessment of pulmonary vein (pv) reconnections

Abstract Background Traditionally, circular mapping catheters (CMC) have been considered superior to other designs for mapping pulmonary vein reconnections due to the circular shape of the PV ostium. The grid multipolar catheter produces higher definition maps potentially overcoming the disadvantage of being rectangular. Purpose We assessed the acute procedural results, comparing Grid versus CMC in the setting of PV re-isolation to understand if one was superior to the other. Methods In this multicentre randomised controlled trial, 169 patients (62% male; median age 66 years [22-83) underwent repeat ablation, between July 2021 and March 2023, for recurrent symptomatic atrial arrhythmias. We undertook two LA maps for patients, utilising the Grid and the CMC. Blinded maps were collected with both catheters, followed by randomisation to one map for analysis and ablation. The primary outcome was the radiofrequency time required to isolate the pulmonary veins. Secondary outcomes include LA mapping time and density for both catheters, ability to identify pulmonary vein sleeves and duration of the ablation procedure. Results 126 patients had PV reconnections. 66 patients (64% male; median age 65 years [22-83]) in the Grid arm and 60 patients (68% male; median age 65.5 years [31-83]) in the CMC arm. There was one pericardial effusion and one TIA. There was no significant difference (p=0.202) found in the RF time required to achieve PV isolation in both Grid (mean RF time 200 ± 232 secs) vs CMC (mean RF time 169 ± 298 secs) arms. There was no significant difference (p=0.407) found between LA mapping time for the CMC (mean 1047 ± 454 seconds) and the Grid (Median 1080 ± 440 seconds). There was no significant difference (p=0.411) found in the total procedure time for the CMC (mean 122.7 minutes) and the HD grid (130 minutes). There were significantly more (p<0.001) PV mapping points identified with the grid (mean 354±213 points) than the CMC (mean 234±154 points) arm. There was no significant difference in PV sleeve reconnections found (p=0.106) between the grid (120 PV sleeve reconnections with a mean 1.4±0.71 reconnections) and the CMC (98 PV sleeve reconnections with a mean 1.52±0.72 reconnections). Both maps were analysed to assess reconnections on opposing catheter arms. The grid identified 20 PV sleeve reconnections not visible on the CMC, whilst 9 were visible on the CMC and not the grid. Conclusion There was no significant difference found in RF time, mapping time and overall procedure time. The Grid identified more reconnections not seen with the CMC and had an overall improved mapping density suggesting that this configuration could be superior for LA mapping.

Multi-Objective Optimization Strategy for Commercial Vehicle Permanent Magnet Water Pump Motor Based on Improved Sparrow Algorithm

In order to achieve multi-objective optimization for a permanent magnet water pump motor in heavy commercial vehicles, we propose a strategy based on response-surface methodology and the improved sparrow algorithm (CGE-SSA). Firstly, the output capacity of the pump during actual operation was tested with an experimental bench to determine the design parameters of the motor, and then its modeling was completed using Ansys Maxwell 2022r2 software. Secondly, the response-surface model was established by taking the parameters of permanent magnet width, rib width, and slot width as optimization parameters and the output torque (Ta), torque ripple (Tr), and back electromotive force (EMF) amplitude as optimization objectives. Meanwhile, three methods—namely, circular sinusoidal chaotic mapping, improved golden sinusoidal strategy, and adaptive weight coefficients—were used to improve the convergence speed and accuracy of the sparrow search algorithm (SSA). Finally, the multi-objective optimization of the permanent magnet synchronous motor was completed using the improved sparrow algorithm. A comparative analysis of the motor’s output before and after optimization showed that the torque pulsation and reverse electromotive force of the motor were significantly improved after optimization.

In vivo safety and pulmonary vein isolation performance of a new cryoballoon for the treatment of atrial fibrillation.

Cryoablation to achieve pulmonary vein (PV) isolation has become one of the standard approaches for atrial fibrillation (AF) ablation. The Arctic Front series cryoballoon and Achieve circular mapping catheter (Medtronic) inherently possess design defects that have been associated with unfavorite clinical outcomes. Lately, a new cryoablation system (Nordica Cryoablation System, Synaptic Medical) was developed with improved design of the cryoballoon and circular mapping catheter to address the inadequacies of current cryoablation technology. An animal study was conducted to test the efficacy and safety in performing PVI with the Nordica Cryoablation System. Pulmonary vein isolation with the Nordica Cryoablation System was performed on 12 PVs of six healthy canines. Acute PVI and peri-procedural complications were recorded. All animals underwent a repeat EP study at least 4 weeks after index procedures followed by pathological and histological assessments of the heart and collateral/downstream organs after planned euthanasia. Acute PV isolation was achieved in all targeted PVs with 50% of PVs being isolated with a single cryoablation application. There were no major peri-procedural complications or device malfunction events. All PVs remained isolated after 29-30 days follow-up. Histological examination showed transmural cryo-lesions at treated sites with minimal inflammation, neovascularization, and neointima formation but no significant injury to adjacent tissue or embolization in downstream organs. Acute and durable PVI can be achieved by using the novel Nordica Cryoablation System. Ablation with this new cryoablation system is associated with transmural lesions at targeted myocardium but creates no injury to the collateral tissues or downstream organs.

Single versus double transseptal puncture for pulmonary vein isolation with radiofrequency catheter ablation for atrial fibrillation - insights from "Go for Zero Fluoroscopy" registry

Abstract Background Transseptal puncture is one of the most challenging steps in catheter ablation of atrial fibrillation (AF) because of the potential risk of complication. While single TSP reduces the puncture-related risk, double TSP simplifies the procedure (immediate signal visualization in pulmonary veins, avoidance of multiple changes of catheters through the single sheath). The purpose of this study was to analyze the impact of single versus double TSP during pulmonary vein isolation (PVI) with radiofrequency (RF) catheter ablation for AF on the fluoroscopy usage and procedure time. Methods Data reported from the international, multicenter prospective „Go For Zero Fluoroscopy Registry" performed in years 2018–2019 were analyzed. Overall 25 European electrophysiology centers from 14 countries and up to 5 operators from each center were enrolled. Only isolated PVI procedures were analyzed. Results A total data of 393 PVI RF procedures were collected from 25 centers. The median dose-area-product (DAP), fluoroscopy time and overall procedure time were: 810 (325 – 1839) cGy*cm2, 8 (4 – 14) minutes and 124 (92 – 168) minutes, respectively. Single TSP was associated with significantly higher DAP: 984 (459 – 1939) vs 667 (227 – 1469) cGy*cm2 (p=0.002), longer fluoroscopy time: 11 (6 – 19) vs 6 (3 – 11) minutes (p<0.001) and longer overall procedure time: 133 (103 – 168) vs 110 (90 – 168) minutes (p=0.003) as compared with double TSP. Single and double TSP group did not differ significantly in regards of general anesthesia usage, circular and multipolar mapping catheter use (p>0.05). However, single TSP was performed by operators with longer EP lab experience: 10 (4 – 15) vs 3 (0 – 10) years (p<0,001). Conclusions Double TSP is related with lower fluoroscopy usage and shorter overall procedure time of pulmonary vein isolation with radiofrequency catheter ablation for atrial fibrillation.

Different predictors of AF recurrence after pulmonary vein isolation with cryoballoon and radiofrequency ablation: insights from clinical and electroanatomical mapping data of the NO-PERSAF study

Abstract Background Pulmonary vein isolation (PVI) with cryobaloon ablation (CBA) and radiofrequency ablation (RFA) lead to a similar outcome of freedom from atrial tachyarrhythmia (ATA) during follow-up as showed by the NO-PERSAF study. Analyses of ATA recurrence for these two techniques based on data of electroanatomical mapping (EAM) are scarce from randomized clinical trials. Purpose This study aimed to evaluate and compare clinical outcomes and EAM data recorded in the left atrium (LA) during CBA and RFA procedures in patients with persistent atrial fibrillation (AF). Methods For the NO-PERSAF study, 101 patients (mean 63.2±8.6 years, 80 male, 21 female) with persistent AF (77 persistent AF, 24 long-standing persistent AF) referred to PVI were randomized (1:1) to CBA or RFA and followed for 12 months. A prolonged 3-year follow-up was carried out. EAM was performed by a circular mapping catheter with a 3-dimensional mapping system in all patients. EAM data were recorded and analyzed off-line. The areas of the LA, posterior wall, low-voltage (<0.5mV) and complex fractionated electrogram (cycle length <120 ms) were measured and corrected by body surface area (BSA). EAM data from 90 patients were qualified for further analysis and the others (5 in CBA and 6 in RFA) excluded because of disqualification or technical failure of recording. Correlation between clinical results of 3-year follow-up and the EAM data were analyzed using univariate cox regression. Results After 3-year follow-up, freedom from ATA was achieved in 51 (50.5%) of the 101 patients, 28 (54.9%) out of 51 patients in the CBA group and 23 (46.0%) out of 50 patients in the RFA group and no difference was found (p=0.327). RFA compared with CBA resulted in larger ablation lesions in the LA (23.9% vs. 21.3%; p=0.037) and particularly in the posterior wall (44.2% vs 31.8%; p<0.001). Compared between the patients with and without recurrence, there was no difference with respect to age, gender, AF history, body mass index, heart disease and CHA2DS2-vasc score. For EAM data, the area of the LA and low voltage were significantly higher in ATA recurrent patients in CBA group, but not in RFA group (Table 1). Univariate cox regression analyses suggested that 3-year follow-up outcomes were associated with the size of the LA and the amount of low voltage corrected by BSA. The criteria of the LA area >55 cm2/m2 or low voltage area <19 cm2/m2 could predict ATA recurrence after CBA, but not after RFA procedure (Figure 1). Conclusions The size of the LA and the amount of low voltage corrected by BSA was associated with the outcomes of PVI during follow-up and could be employed as predictors of ATA recurrence for CBA, but not for RFA procedure.Table 1Figure 1K-M curves after CBA and RFA

Intelligent filter to remove artifact during cryo freezing for pulmonary vein isolation increases the time window for observation of time of isolation

Abstract Introduction Time to pulmonary vein isolation (PVI) during cryo balloon (CB) PVI is a critical data point in characterizing the pulmonary vein (PV) isolation status as it improves clinical outcomes. PV potentials on the circular mapping catheter may be obscured by power line artifact during the freeze process as ice forms near the electrode. This study assesses the ability of an intelligent digital filter to sample, predict and remove noise from PV electrograms during the freeze cycle to increase the time window available to observe the abolition of PV potentials. Method An intelligent filter that detects and removes power line related signal artifact was developed. The filter algorithm was then retrospectively applied to electrograms collected during delivery of cryo energy in the PVISION trial of the PVI Analyzer study previously described. The PV potential amplitude immediately before the delivery of cryo energy was recorded. During the freeze cycle, artifact amplitude was measured and the time required for the noise to exceed that of the original PV potential recorded. This operation was repeated with the application of the predictive filter. An example of an analysis of a single bipolar trace is shown in Fig 1. Results The PVISION trial included 47 patients who underwent a cryo PVI procedure (42% female, mean age 59 years, +/- 11 years). Of those, 24 cases and 68 vein cryo applications had sufficient information about when the cryo freeze cycle started and ended. Of these 68 veins treated, 33 exhibited power line noise on one or more bipolar traces during the freeze cycle (49%). The mean amplitude of PV potentials before application of energy was 0.49 mV (+/- 0.79 mV) and the mean time to artifact exceeding this level was 69 (+/-50 seconds), across all bipolar traces with freeze noise present. After application of the intelligent filter, the mean time to artifact exceeding the baseline PV amplitude increased to 82 seconds (+/- 57 seconds), across all bipolar traces with freeze noise present. In 44 veins noise amplitude never exceeded PV potential amplitude on any of the bipolar traces during the freeze after application of the intelligent filter. Paired analysis of the average time of noise exceeding the PV potential amplitude during the freeze was 116 s before application of the filter and 26 s with the filter applied. See Fig 2. for a summary of the results. Conclusion An intelligent digital filter designed to remove artifact from electrograms during cryo ablation procedures might increase the time window before noise saturates PV potentials and, in some cases, remove noise such that it never exceeds that of the PV potential.Fig 1 Example of noise and filteringFig 2. Summary of results

Radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique: 9-year outcome

Abstract Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory atrial fibrillation. Cryoablation has been shown to be a safe and effective technique for pulmonary vein isolation. However, there is a significant arrhythmia recurrence rate after cryoablation procedures and there are no established strategies for redo procedures in these patients. Therefore, we have summarized our experience with radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique (including an analysis of pulmonary vein conduction recovery patterns after procedures performed with the first or second generation cryoballoon). Methods Two hundred and twenty patients (paroxysmal AF: 140 patients, persistent AF: 80 patients) had to undergo a redo procedure after initially successful circumferential PV isolation with the cryoballoon technique (First generation: 110 patients (group A); second generation: 110 patients (group B)). The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy (three-dimensional mapping system) depending on the intra-procedural findings. Results During the redo procedure, a mean number of 1.6 re-conducting PVs were detected (using a circular mapping catheter; group A: 2.2 re-conducting PVs, group B: 1.0 re-conducting PVs). There was a slightly higher incidence of chronic PV reconnections related to the left-sided PV ostia than to the right-sided PVs in both groups. Furthermore, sites of chronic PV reconnection were found more frequently in the inferior parts of the PV ostia than in the superior parts. In 97 patients in group A, a segmental approach was sufficient to eliminate the residual PV conduction because there were only a few recovered PV fibers (1-3 reconnected PVs; group A1). In the remaining 13 patients in group A, a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction of all four pulmonary veins (group A2). In group B, a segmental approach was sufficient in nearly all patients (109/110) because there was only a minor reconnection of 1-2 PVs. All recovered PVs could be isolated sucessfully again. At 108-month follow-up, 69.1 % of all patients were free from an arrhythmia recurrence (152/220 patients; group A: 72/110 patients (65.5 %), group B: 80/110 patients (72.3 %)). There were no major complications in both groups. Conclusions In patients with an initial circumferential PVI using the cryoballoon technique, a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation. In most cases only a few re-conducting PV fibers were found and therefore, a segmental re-ablation approach seems to be sufficient in the majority of patients (especially in patients treated with the second generation cryoballoon).

The contribution of pulmonary veins to the mechanism of persistent AF is dependent on their extent of electrical connection

Abstract Introduction Success rate of pulmonary vein isolation (PVI) is lower in patients with persistent AF (peAF) compared to paroxysmal AF. The indiscriminate use of adjunctive catheter ablation (CA) strategies beyond PVI involve potential risks and new areas of iatrogenic arrhythmogenesis. Thus, distinguishing patients with peAF who may be cured with PVI-only from those who need CA beyond PVI would allow a more efficient patient-tailored CA strategy. Purpose We aimed to evaluate whether the circumferential extent of PV electrical connection assessed during pre-ablation mapping predicts the success rate of a PVI-only CA strategy. Methods Consecutive patients with peAF undergoing first CA consisting of a PVI-only CA were included. The extent of PV electrical connection was assessed using a circular mapping catheter placed within the PVs prior to ablation. Based on their follow-up (FU), patients were considered: a) PVI-responders, in the absence of AF or atrial flutter recurrence ≥ 12 months off-anti-arrhythmic drugs, b) PVI-non responders, in case of AF recurrence despite absence of any PV reconnection at reintervention, or despite one reintervention consisting of stand-alone residual PV connection ablation, c) PVI response was considered as indeterminate for all other instances (eg. Sinus rhythm maintenance on-AAD, shorter FU, etc). Results 148 patients were included (mean age 64 ± 9.7 years, mean peAF duration 7.3 ± 7 months). After a mean FU of 18 months after last PVI, we identified 60 PVI-responders and 25 PVI- non responders. In the remaining 63 patients, PVI response was indeterminate. In PVI-responders, the median percentage of the PV circumference displaying PVs potentials was significantly higher compared to PVI-non responders (68% vs. 60%, respectively; p=0.035). Conclusions The circumferential extent of PVs connection is correlated to the success rate of a stand-alone PVI CA strategy in patients with peAF. It may be a marker of the contribution of PVs to AF. Patients with poorly connected PVs during index CA ablation may warrant additional ablation strategies beyond PVI.

Circular Differential Photocurrent Mapping of Hot Electron Response from Individual Plasmonic Nanohelicoids.

Chiral plasmonic nanocrystals have recently attracted increasing attention in circular polarization-dependent photocatalysis driven by hot carriers. While being concealed in traditional ensemble measurements, the individual chiral photocatalytic activity of nanocrystals can exclusively be revealed by directly correlating the circular differential photocurrent response to helical morphologies using single-particle techniques. Herein, we develop a method named circular differential photocurrent mapping (CDPM) and demonstrate that CDPM can be used to characterize the circular differential hot electron (CDHE) response from individual Au nanohelicoids (AuNHs) on a TiO2 photoanode in a photoelectrochemical cell. The single-particle circular differential scattering and CDHE measurements were interpreted with calculations performed on a model in direct correlation to the helical morphologies of the nanocrystal. While CDHE response was found inactive at a dipolar resonance of 750 nm, helicity-convoluted sites of HE generation were identified on the AuNH at a specific higher-order mode of 550 nm, resulting in a significant response of CDHE in association with the handedness of the AuNH. Details of circular differential contributions were further resolved by examining the efficiencies of individual AuNHs in terms of g-factors. Our study provides a powerful microscopic method at the single-particle level for the photocatalytic characterization of chiral nanocrystals, gaining fundamental insights into the photocatalysis of chirality, especially toward plasmon-induced asymmetrical photochemistry or photoelectrochemistry.

Validation of a machine learning algorithm to identify pulmonary vein isolation during ablation procedures for the treatment of atrial fibrillation: results of the PVISION study.

Pulmonary vein isolation (PVI) is the cornerstone of ablation for atrial fibrillation. Confirmation of PVI can be challenging due to the presence of far-field electrograms (EGMs) and sometimes requires additional pacing manoeuvres or mapping. This prospective multicentre study assessed the agreement between a previously trained automated algorithm designed to determine vein isolation status with expert opinion in a real-world clinical setting. Consecutive patients scheduled for PVI were recruited at four centres. The ECGenius electrophysiology (EP) recording system (CathVision ApS, Copenhagen, Denmark) was connected in parallel with the existing system in the laboratory. Electrograms from a circular mapping catheter were annotated during sinus rhythm at baseline pre-ablation, time of isolation, and post-ablation. The ground truth for isolation status was based on operator opinion. The algorithm was applied to the collected PV signals off-line and compared with expert opinion. The primary endpoint was a sensitivity and specificity exceeding 80%. Overall, 498 EGMs (248 at baseline and 250 at PVI) with 5473 individual PV beats from 89 patients (32 females, 62 ± 12 years) were analysed. The algorithm performance reached an area under the curve (AUC) of 92% and met the primary study endpoint with a sensitivity and specificity of 86 and 87%, respectively (P = 0.005; P = 0.004). The algorithm had an accuracy rate of 87% in classifying the time of isolation. This study validated an automated algorithm using machine learning to assess the isolation status of pulmonary veins in patients undergoing PVI with different ablation modalities. The algorithm reached an AUC of 92%, with both sensitivity and specificity exceeding the primary study endpoints.

The genome of the Arctic snow alga Limnomonas spitsbergensis (Chlamydomonadales).

Snow algae are a diverse group of extremophilic microeukaryotes found on melting polar and alpine snowfields. They play an important role in the microbial ecology of the cryosphere, and their propagation on snow and ice surfaces may in part accelerate climate-induced melting of these systems. High-quality snow algae genomes are needed for studies on their unique physiology, adaptive mechanisms, and genome evolution under multiple forms of stress, including cold temperatures and intense sunlight. Here, we assembled and annotated the genome of Limnomonas spitsbergensis, a cryophilic biciliate green alga originally isolated from melting snow on Svalbard, in the Arctic. The L. spitsbergensis genome assembly is based primarily on the use of PacBio long reads and secondly Illumina short reads, with an assembly size of 260.248 Mb in 124 contigs. A combination of 3 alternative annotation strategies was used including protein homology, RNA-seq evidence, and PacBio full-length transcript isoforms. The best merged set of annotations identified 18,277 protein-coding genes, which were 95.2% complete based on Benchmarking Universal Single-Copy Orthologs analysis. We also provide the annotated mitogenome, which is a relatively large 77.942 kb circular mapping sequence containing extensive repeats. The L. spitsbergensis genome will provide a new resource for research on snow algae adaptation, behavior, and natural selection in unique, low-temperature terrestrial environments that are under threat from climate change.

Method, safety, and outcomes of persistent AF ablation without a circular mapping catheter: 3 years experience of a Belgian Tertiary Centre

Background We aimed to share our methods and experience of persistent AF ablation without a circular mapping catheter (CMC), thereby avoiding femoral venous and transseptal punctures, decreasing the cost of the procedure, and possibly reducing the duration of the procedure and fluoroscopy time. Methods We report our experience with 261 persistent AF ablations performed without a CMC over the past 3 years. Results The procedures were performed with no apparent loss of efficacy or safety. Freedom from recurrence was defined as a 1-year absence of AF/atrial flutter (AFL) episodes >30 s, beyond the 3-month blanking period. At 1 year, 72% of the patients were free from arrythmias. Conclusions Persistent AF ablation is feasible without a CMC, reducing the need for venous and transseptal punctures and the cost of the procedure. We suggest that prospective studies should aim to characterise the reduction in procedure and fluoroscopy times as a result of this technique.

Mundane circular economy policy: Mainstreaming CE education through the agency of schools

This study examines the ways in which the implementation of Circular Economy (CE) principles in basic education in Indonesia contribute to advancing sustainability transitions. The research addresses two key questions. First, how can the disparity between CE principles and their application in everyday practices within educational institutions be effectively bridged? And second, to what extent does this bridging process facilitate the transformation of schools toward the CE paradigm? Employing technologically enabled multi-criteria mapping methods, this study implements an action-based approach which include school principals on Java Island, Indonesia, from 2022 to 2023. The research reveals the significance of using practical mapping tools, specifically (1) mundane circular school decision mapping, (2) mundane decision prioritization map, and (3) transformative pathways for CE transition, for bridging the gap between CE principles and practical application. These outputs, which were collaboratively produced by researchers and school principals, draw insights from current practices and reflections on the Indonesia Green Principal Awards (IGPA) program, which fosters circular transformation in educational institutions. This research contributes to the introduction of mundane circular economy policy concept which illustrate the everyday dimension of circular economy practices at the grassroots level by integrating CE principles into basic education, contributing significantly to the broader global sustainability agenda.

Photo-acoustic spectroscopy with widely tuneable laser enables circular dichroism mapping

Sensitive and reliable characterization of chirality in nanostructures and molecules is of great importance in multidisciplinary research combining physics, chemistry and nanotechnology, with potential applications in pharmaceutical and agrochemical industry. Chirality is connected to circular dichroism (CD) - the absorption difference when the chiral medium is excited with circular polarizations of opposite handedness. Hence, measuring chirality by direct absorption measurements is of great interest in nanophotonics and plasmonics community, where the nanostructured media can enhance chiro-optical effects. Here we present a recently constructed photo-acoustic spectroscopy (PAS) set-up, which offers many degrees of freedom in characterization. We use a laser which is widely tuneable in the near-infrared (680-1080 nm) and visible (340-540 nm) ranges. The laser output is modulated with a mechanical chopper, where its frequency defines the penetration depth of the thermal signal. The input polarization is controlled by a linear polarizer and a quarter-wave plate, and the laser can be focused before impinging on the sample in the tightly closed photo-acoustic cell. The cell is placed on translational and rotational stages, which allows for the spatial mapping and extrinsic chirality measurements. Finally, a sensitive microphone measures the pressure changes in the cell, enabling scattering-free measurement of absorption and CD.

Genetic Architectures of Medical Images Revealed by Registration of Multiple Modalities

The advent of biobanks with vast quantities of medical imaging and paired genetic measurements creates huge opportunities for a new generation of genotype–phenotype association studies. However, disentangling biological signals from the many sources of bias and artifacts remains difficult. Using diverse medical images and time-series (ie, magnetic resonance imagings [MRIs], electrocardiograms [ECGs], and dual-energy X-ray absorptiometries [DXAs]), we show how registration, both spatial and temporal, guided by domain knowledge or learned de novo, helps uncover biological information. A multimodal autoencoder comparison framework quantifies and characterizes how registration affects the representations that unsupervised and self-supervised encoders learn. In this study we (1) train autoencoders before and after registration with nine diverse types of medical image, (2) demonstrate how neural network-based methods (VoxelMorph, DeepCycle, and DropFuse) can effectively learn registrations allowing for more flexible and efficient processing than is possible with hand-crafted registration techniques, and (3) conduct exhaustive phenotypic screening, comprised of millions of statistical tests, to quantify how registration affects the generalizability of learned representations. Genome- and phenome-wide association studies (GWAS and PheWAS) uncover significantly more associations with registered modality representations than with equivalently trained and sized representations learned from native coordinate spaces. Specifically, registered PheWAS yielded 61 more disease associations for ECGs, 53 more disease associations for cardiac MRIs, and 10 more disease associations for brain MRIs. Registration also yields significant increases in the coefficient of determination when regressing continuous phenotypes (eg, 0.36 ± 0.01 with ECGs and 0.11 ± 0.02 for DXA scans). Our findings reveal the crucial role registration plays in enhancing the characterization of physiological states across a broad range of medical imaging data types. Importantly, this finding extends to more flexible types of registration, such as the cross-modal and the circular mapping methods presented here.

High efficiency single-catheter workflow for radiofrequency atrial fibrillation ablation in the QDOT catheter era.

High-power short-duration (HPSD) ablation may improve the consistency and efficiency of pulmonary vein isolation (PVI). The novel QDOT Micro™ catheter (Biosense Webster, Inc.) with temperature feedback and microelectrodes aims to enhance PVI efficiency and safety. This study wants to evaluate the feasibility, safety, and efficiency of a standardized single-catheter workflow for PVI using QDOT (Q-FLOW). The Q-FLOW includes single transeptal access, radiofrequency encircling of the PVs using a power of 50 W in a temperature/flow-controlled mode, and validation of the circles with microelectrodes. A 1:1 propensity-matched cohort of patients treated with conventional power-controlled ablation using a circular mapping catheter (CMC-FLOW) was used to compare procedural and clinical outcomes. A total of 150 consecutive atrial fibrillation patients (paroxysmal 67%, persistent 33%) were included. First-pass isolation rate was 86%. Procedural time, X-ray time, and dose were significantly lower for the Q-FLOW vs the CMC-FLOW (67.2 ± 17.9 vs 88.3 ± 19.2min, P < 0.001; 3.0 ± 1.9 vs 5.0 ± 2.4min, P < 0.001; 4.3 ± 1.9 vs 6.4 ± 2.3 Gycm2, P < 0.001). Complications were numerically but not significantly lower in the Q-FLOW group (2 [1.3%] vs 7 [4.7%], P = 0.091). There was no difference in arrhythmia recurrence at 12months (atrial arrhythmia-free survival rate, 87.5% vs 84.4%, P = 0.565). A streamlined single-catheter workflow for PVI using QDOT was feasible and safe, resulting in a high rate of first-pass isolation and a low complication rate. The Q-FLOW further improved the efficiency of PVI compared to the standard CMC-FLOW, without difference in the 12-month outcome.

Unlocking circular economy potential: evaluating production processes through circular value stream mapping in real case studies

PurposeThe purpose of this study is to propose a new mapping tool called Circular Value Stream Mapping (C-VSM) that combines Circular Economy principles with Lean tools to enhance sustainability performance in operations.Design/methodology/approachTo develop the C-VSM tool, the researchers conducted a literature review and a focus group. The tool was then applied to two real case studies in the agri-food sector, specifically analyzing an artichoke and olive oil producer, to assess its validity and effectiveness.FindingsThe study introduces the Circular Resource Box (CRB) as a key innovation in the C-VSM tool. This visual representation effectively captures resource circularity and how resources and wastes are managed, making it easy to identify circularity in the production process. By combining qualitative and quantitative information with this visual representation, companies can identify improvement opportunities aligned with the CE.Research limitations/implicationsThe research is limited in scope as it focuses on the application of the C-VSM tool in the agri-food sector. Further research could explore its applicability in other industries and settings to understand its broader impact.Practical implicationsThe C-VSM tool provides practical benefits to companies seeking to transition from linear to circular production processes. It enables practitioners to identify opportunities to reduce environmental impacts and optimize production operations in line with CE.Originality/valueThe introduction of the C-VSM tool is a novel approach that bridges the gap between Lean Manufacturing and CE concepts, advancing the understanding of how CE thinking can be effectively implemented in operations.

Circular RNA mapping reveals CircCWC22 as a MiR-3059-x sponge in yak fat deposition by regulating HMGCL

The regulatory mechanisms and functions of circular RNAs (circRNAs) in yak intramuscular fat (IMF) deposition remain unclear. This study aimed to investigate yak circRNAs with high and low IMF content using high-throughput sequencing. A total of 270 differentially expressed circRNAs were identified, of which 129 were upregulated and 141 were downregulated. Among these circRNAs, circCWC22, derived from the yak CWC22 gene, was further studied to understand its functions and regulatory mechanisms. Sequencing and RNase R processing confirmed the circular nature of circCWC22. By constructing a circRNA-miRNA-mRNA co-expression network, the potential regulatory pathway of circCWC22/miR-3059-x/HMGCL was identified. To investigate the roles of circCWC22, miR-3059-x, and HMGCL in the deposition of yak intramuscular preadipocytes (YIMAs), CCK-8, EdU, BODIPY, triglyceride content, and qRT-PCR analyses were performed. The results demonstrated that circCWC22, miR-3059-x, and HMGCL promoted the differentiation and inhibited the proliferation of YIMAs. Using the dual-luciferase reporter system and qRT-PCR, we confirmed that circCWC22 adsorbed miR-3059-x, and HMGCL was identified as a target gene of miR-3059-x. In conclusion, this study uncovered a large number of potential circRNAs involved in IMF deposition and highlighted the significant role of circCWC22 in yak IMF deposition via the circCWC22/miR-3059-x/HMGCL axis.

Initial clinical experience of atrial fibrillation ablation guided by a cryoballoon-compatible, magnetic-based circular catheter.

The circular catheter compatible with current cryoballoon system for atrial fibrillation (AF) ablation is exclusively sensed by impedance-based electro-anatomical mapping (EAM) system, limiting the accuracy of maps. We aim to investigate the feasibility and safety of a magnetic-based circular mapping catheter for AF ablation with cryoballoon. Nineteen consecutive patients who underwent pulmonary vein isolation (PVI) with cryoballoon for paroxysmal or persistent AF were included. EAMs of left atrium (LA) created by the LASSOSTAR™NAV catheter (Lassostar map) before and after PVI were compared to that generated by a high-density mapping catheter (Pentaray map) from different aspects including structural similarity, PV angle, LA posterior wall (LAPW) and low voltage areas (LVAs), and the amplitude of far field electrograms (FFEs) recorded by catheters. All patients had successful PVI without major complications. With similar mapping time and density, the LA volume calculated from the Pentaray map and Lassostar map were comparable. There were no significant differences in PV angle of all PVs and PW area (16.8 ± 3.2 vs. 17.1 ± 2.8, p = .516) between Pentaray map and Lassostar map. High structural similarity score was observed between two maps (0.783 in RAO/LAO view and 0.791 in PA view). Lassostar map detected lesser but not statistically significant extension of LVA (13.9% vs. 18.3%, p = .07). Amplitude of FFE was larger at the right superior PV on Lassostar map (0.21 ± 0.16 vs. 0.14 ± 0.11 mV, p = .041) compared to that on the Pentaray map. In our initial experience, PVI with cryoballoon and magnetic-based circular LASSOSTAR™NAV catheter was safe and effective based on the accurate LA geometry it created.