Additional RF Research Articles

LOW SALINITY WATER INJECTION EVALUATION AND MATURE FIELD DEVELOPMENT AT ANGGORO SHALLOW SAND, SANGASANGA FIELD

AbstractAnggoro's shallow sand was perforated at well ANG-1033 (D4-N1 layer). Oil production in this well increased from an average of 15 BOPD to 170 BOPD. That the perforated layer was affected by low salinity water injection (salinity < 3000 ppm). Evaluation of water injection sweep efficiency was carried out using the Dykstra-Parson method, vertical efficiency of about 0.3, area efficiency of 0.7, and displacement efficiency of 0.3. The Estimated Ultimate Recovery (EUR) of this well provides is 197 MBbls with an additional RF of around 20 %. This increase is due to the low salinity water injection sweep mechanism that occurs. The clay content plays an important role in the mechanism that occurs in this layer, these mechanisms fines migration, increase in pH, multi ion exchange, double layer effect, and salting in which these mechanisms result in increased oil recovery. Seeing the production results from the D4-N1 layer and oil production in this layer can still be maximized, in the future this layer can be developed with several programs such as reactivation, workover, and development drilling.Keywords: Low salinity water injection, shallow layer, efficiency

Modification of deceleration zones and late potentials after ventricular tachycardias substrate ablation

Abstract Introduction Characterization of ventricular substrate is crucial during ventricular tachycardias (VT) ablation. Isochronal Late Activation Mapping (ILAM) is a recently introduced visualization tool that permit to identify areas of slow conduction (deceleration zones, DZs), these seems to well correlate with VT isthmuses. However, there are limited data about changes in this substrate after catheter ablations. Purpose To evaluate changes that occur to DZs and late potentials (LPs) after repeated ablative lesion sets. Methods High density voltage map and ILAM of the left ventricles (LV) during paced rhythm were performed in all cases. LV activation map was divided into 8 isochrones and DZ was defined as the presence of 3 isochrones within 1 cm-radius. LPs were defined as EGMs with late and fragmented components after the QRS. PES was performed at the beginning and at the end of the procedure. Each RF lesion set were applied with force-sensing irrigation catheter (target LSI 6-6.5) to abolish all the DZs and LPs discovered at baseline. After the first lesion set a re-map was performed looking for persistent DZs or LPs in the same LV segment (residual) or the appearance in a new ones (shift) in a 17-segment LV model; additional RF lesions and maps were performed only if DZs or LPs were still present in the last map. Results Of 28 VT cases considered, 9 patients with detailed LV maps and subsequent remaps were analyzed. Median age was 66 yo, 8 males, 7/9 with ischemic heart disease. In 7/9 patients clinical VTs were also induced and mapped. At baseline ILAM maps identified 24 DZs; after the first lesion set, 9 DZs were still appreciable at the same localization and 9 shifts to another LV segment (e.g. fig1). In 100% of patients at least one DZ was still appreciable at the first remap, while in 78% of patients a shift of the previous one was noted. At remap after a second lesion set 9 DZs were still present (3 residual, 6 shifts) in 33% of pts. Finally after a third lesion set only 2 DZs were still present in the same segment and then abolished. Furthermore, at baseline LPs were present in 28 LV segments, and after the first lesion set LPs were still present in 15 segments (9 residual, 6 new LPs). At first remap 78% of patients still showed LPs. After a second lesion set LPs were still visible in 6 segments (3 residual, 3 shift) in 22% of patients. In the third remap only in 2 segments could still be appreciated (1 residual, 1 shift) and finally were all abolished (summary in fig2). In 5/7 patients the clinical VT isthmus were identified in a DZ at baseline. At median FU of 6 months 7/9 patients has no VT recurrences, while there was one non-cardiovascular death. Conclusions Frequently DZs and LPs persistence is observed after first sets of lesions and additional RF deliveries are required for complete abolition. Remapping often demonstrates that both DZs and LPs move to other adjacent LV segments, likely where they were previously masked.Fig1Fig2

Electrophysiological characteristics and durability of index pulsed field ablation lesions from redo procedures for atrial arrhythmia recurrences

Abstract Background Catheter ablation for atrial fibrillation (AF) has been performed using mainly thermal energy sources (radiofrequency, cryo, or laser). Pulsed field ablation (PFA) is a novel energy with interesting safety and effectiveness demonstrated in previous preclinical and clinical trials. Purpose We sought to assess the electrophysiological characteristics and durability of PFA index procedure procedures using a pentaspline PFA catheter as assessed based on redo procedures in patients with AT/AF recurrences. Methods A total of 169 patients (paroxysmal AF (PAF), 120; persistent AF (PsAF), 49) who underwent PFA using a pentaspline PFA catheter in the index procedure from November 2021 to July 2023 were studied. Pulmonary vein isolation (PVI) was performed with PFA in all patients with additional PFA lines: i)posterolateral mitral isthmus (MI) ablation in 25, ii) posterior line in 40 patients. Twenty-seven patients (PAF, 11; PsAF, 16) had atrial arrhythmia (atrial tachycardia (AT) or AF) recurrence after a 3-month blanking period (16%). We analyzed the electrophysiological characteristics of previous PFA lesions in 18 (PAF, 8; PsAF, 10) out of 27 patients in whom an activation and voltage mapping using 3-D electroanatomical mapping system was available. Results PV reconnections were identified in 7 of 18 patients (13PVs/69PVs ,18.8%) at the PV-LA junctions and carina regions of both left PVs and right PVs, mainly at the anterior aspect of right PV carina (n=6). In 6 out of 10 redo cases, posterolateral MI line using PFA was performed in the index procedure based on our strategy for PsAF ablation. In these 6 cases with previous MI line using PFA for PsAF ablation endocardial PFA was combined with marshall vein ethanolization(Et-VOM). Additional RF endocardial ablation and in the CS was needed to achieve MI block in 2 (33%) in the index procedure. 3D mapping of redo cases showed MI line gaps in 6/6 (100%). In 3 of those patients, the clinical arrhythmia recurrence was a perimitral AT (50%). Nine of the 10 PsAF patients who underwent a redo procedure had an index procedure complete posterior line. Remapping demonstrated durable block in 7/9 (78%). One of these patients presented with a roof dependent AT diagnosed in the redo procedure. Durable posterior lines received a significantly larger number of PFA deliveries during the index procedure: 16.4±3.3 vs 10.0±2.8 respectively, p=0.041). Conclusion This study based on redo cases after PFA using a pentaspline PFA catheter shows that PFA is associated with high durability for PVI and posterior line ablation. However the durability of MI line are poor, even when combined with VOM ethanolization. Further research is needed to define the optimal number of deliveries required to achieve durable posterior line block.

A Method Based on Artificial Intelligence That Predicts Arabica Coffee Yield by Analyzing Abiotic Factors and the Prevalence of Coffee Leaf Rust

Coffee is a perennial crop that harbors infections throughout the plant, which may worsen illness under favorable circumstances. Coffee leaf rust, a widespread coffee disease and Arabica is susceptible to leaf rust. Disease incidence and severity depend on abiotic variables. Cloudy and constant South-West monsoon weather (June–September) promotes coffee leaf rust growth. In this five-model study, an Extra Tree and Gradient Boosting regression model predicted coffee crop output in Chikamagaluru, Karnataka, with the least error utilizing biotic and abiotic factors. We investigated additional tree, gradient boosting, RF, Decision Tree, and KNN models using biotic and abiotic predictors. Used the independent testing dataset's MSE, MAE, RMSE Root mean square errors, and R-squared errors to compare model performance. The extra tree (R²=0.98 kg/ha ˉ¹ and RMSE = 7.96 kg/ha ˉ¹) and gradient boosting (R²=0.96 kg/ha ˉ¹ and RMSE = 10.96 kg/ha ˉ¹) regression models used Group 1 and 2 characteristics as predictor variables and different parameter fine tuning functions to estimate coffee yield most accurately. Compared to the less precise probabilistic models utilized in this work, such as Random Forest, decision tree, and KNN models, shown in the results section. The optimum weather parameter for coffee production forecasts and biotic-CLR incidence data outperformed random forest, decision tree, and K-Nearest Neighbor models.

A closely spaced two-port MIMO antenna with a radiation null for out-of-band suppressions for 5G Sub-6 GHz applications.

This paper presents the design and isolation enhancement of a filtering MIMO antenna with a radiation null for out-of-band suppressions suited for 5G sub-6 GHz communications. The MIMO antenna offers -10 dB impedance bandwidth functionality at the most prominent partial spectrum of the 5G NR n78 band for enabling wireless applications in base stations, ranging from 3.4 GHz to 3.61 GHz. To mitigate the redundancy of an RF filter and to achieve a strong filtering response, a radiation null is produced in the gain with four identical rectangular slots, which results in a significant gain drop of more than 8 dBi at the stopband. The geometrical design also allows 30 percent size reduction of single element. Subsequently, a closely spaced (0.11λ0) two-port MIMO antenna is implemented and with the utilization of the proposed rectangular shaped hollow stub parasitic element, the interelement isolation is significantly improved by more than 8 dB over the operational frequency range while retaining the filtering without any additional RF structure. The design simplification, peak gain of 5.4 dBi, near ideal response of diversity gain, ECC less than 0.03, congruency between simulated and measured results, and stable parameters make it a valuable choice for 3.5 GHz sub-6 GHz communications.

Machine Learning Prediction of the Experimental Transition Temperature of Fe(II) Spin-Crossover Complexes.

Spin-crossover (SCO) complexes are materials that exhibit changes in the spin state in response to external stimuli, with potential applications in molecular electronics. It is challenging to know a priori how to design ligands to achieve the delicate balance of entropic and enthalpic contributions needed to tailor a transition temperature close to room temperature. We leverage the SCO complexes from the previously curated SCO-95 data set [Vennelakanti et al. J. Chem. Phys. 159, 024120 (2023)] to train three machine learning (ML) models for transition temperature (T1/2) prediction using graph-based revised autocorrelations as features. We perform feature selection using random forest-ranked recursive feature addition (RF-RFA) to identify the features essential to model transferability. Of the ML models considered, the full feature set RF and recursive feature addition RF models perform best, achieving moderate correlation to experimental T1/2 values. We then compare ML T1/2 predictions to those from three previously identified best-performing density functional approximations (DFAs) which accurately predict SCO behavior across SCO-95, finding that the ML models predict T1/2 more accurately than the best-performing DFAs. In addition, we study ML model predictions for a set of 18 SCO complexes for which only estimated T1/2 values are available. Upon excluding outliers from this set, the RF-RFA RF model shows a strong correlation to estimated T1/2 values with a Pearson's r of 0.82. In contrast, DFA-predicted T1/2 values have large errors and show no correlation to estimated T1/2 values over the same set of complexes. Overall, our study demonstrates slightly superior performance of ML models in comparison with some of the best-performing DFAs, and we expect ML models to improve further as larger data sets of SCO complexes are curated and become available for model training.

High efficacy and safety of pulsed electrical field ablation via contact force-controlled radiofrequency catheters for atrial fibrillation ablation with linear lesions in the left atrium

Abstract Background Pulsed Field Ablation have been shown to be efficient and safe for Pulmonary vein isolation (PVI) in catheter ablation of atrial fibrillation (AF). The bipolar application of pulsed electrical energy for electroporation of myocardium has been established with specially designed catheters, which are not used for linear ablation. Purpose We evaluated a novel monophasic PEF ablation technique applied by commercially available CF-controlled catheters for linear ablation lines beyond PVI for treatment of complex AF patients. Methods Patients (n=31, age 64±12 years, 29% females, BMI 29±4) referred for re-ablation of AF and presented with recurrence of persistent AF (n=13) or atypical atrial flutter (n=14) after a PVI procedure, or patients with longstanding persistent AF and severe enlarged atrium (n=4) were included in our patient cohort for additional AF substrate ablation with PEF applications. After high density voltage mapping of the left atrium with multipolar microelectrode catheters, and PVI, or re-PVI was completed (8 patients), additional left atrial linear lesions were performed according to the atrial flutter mechanism or as fibrosis-guided substrate ablation. All but one patient showed low voltage areas (bipolar electrograms <0.5mV) in 35±31% of the left atrial surface. Using contact force sensing catheters, maximal PEF energy pulses were applied with a minimum of 5g contact force and an interlesion distance ≤6mm. Performed linear lesions were left atrial roof line, lateral mitral isthmus line, anterior mitral line, left posterior wall isolation, and cavotricuspid isthmus (CTI) line. Before PEF application close-by a coronary artery (lateral mitral line, CTI) nitroglycerie 0.2mg i.v. was injected. Results Complete lines with exclusively PEF applications and proofed bidirectional conduction block were 100% for roof lines (n=20), posterior wall isolation (n=8), anterior mitral lines (n=10). Exclusively endocardial PEF applications blocked the lateral mitral line in 14 out of 16 cases (88%). Only in two cases additional epicardial RF applications via coronary sinus and endocardial additional RF applications were necessary to complete the mitral isthmus block. In 7 out of 8 cases CTI were blocked by linear PEF applications (88%), however, in one case additional RF applications became necessary. No ECG ST segment elevation was recorded. No serious complications occurred throughout all procedures. Follow up will be available at presentation time. Conclusion Catheter ablation of complex AF patients with linear lesions is performd very efficient and safe with PEF applications by CF-sensing RF ablation catheters. Especially the high efficacy of exclusively endocardial PEF applications for creation of a lateral mitral isthmus block is very promising. However, the long term permanence of the linear lines have to be awaited.

Distribution of triggers in the left atrial posterior wall in AF patients undergoing catheter ablation

Abstract Introduction Having a common embryologic origin with the pulmonary veins (PVs), left atrial posterior wall (LAPW) is considered to be a source of non-PV triggers that facilitate maintenance of atrial fibrillation (AF). However, the benefits of electrical isolation of the posterior wall (PWI) is still debated with contradictory data originating from different ablation approaches. Purpose We report the distribution of triggers in the LAPW area in AF patients undergoing repeat ablation. Methods Consecutive AF patients undergoing catheter ablation between 2015 and 2022 were included in this analysis. PVs were isolated first. Next, high-dose isoproterenol challenge (up to 30µg/min) was used to disclose triggers in the PW by moving the circular mapping catheter along the PW down to the level of coronary sinus, which were targeted using additional RF energy. We defined lower part of LAPW as the area between the line joining the inferior borders of the inferior PV-encircling lesions and the coronary sinus. The endpoint was to achieve electrical isolation, as documented by absence of any electrical activity in the PW. Results Of the 10,963 AF ablations performed during the specified time period, 6249 (57%) had triggers mapped and ablated in the LAPW area. Triggers were seen to be originating from the part of the PW between the PVs in 4124 (66%) and from the lower part of the PW in 2125 (34%) patients. Of these, 1624 (26%) patients had focal triggers detected in both the area between the PVs and the lower PW. All triggers from in between PVs were targeted for ablation, whereas lower PW sites were ablated in 1296 (61%) and not targeted for ablation the remaining 829 (39%). Figure 1 demonstrates the triggers arising from lower PW. At 1 year, amongst patients with lower PW triggers, 1049/1296 (81%) vs 326/829 (39.3%) (p<0.001) were arrhythmia-free. Conclusion Ectopic triggers in the LAPW were documented to be arising from the lower part of the PW in approximately 1/3rd of cases and ablation of those sites resulted in significantly higher success rate.

Tissue characterisation of acute ablation lesions in the right atrium during CMR-guided atrial flutter ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac magnetic resonance (CMR)-guided ablation therapy offers a unique opportunity and incentive to investigate acute ablation lesions. Until present, human studies only used T2-weighted imaging (T2WI) and late gadolinium enhancement (LGE) to assess acute ablation lesions. Purpose To investigate the tissue characteristics of acute ablation lesions during CMR-guided atrial flutter ablation, by combining T2WI and LGE with first-pass perfusion and T1 mapping. Methods Thirteen patients with typical isthmus-dependent atrial flutter were prospectively enrolled and treated with CMR-guided ablation. Pre-ablation tissue characterisation consisted of T2WI and T1 mapping. Postablation imaging was performed directly after application of the primary ablation lesions and included T2WI (n=12), first-pass perfusion (n=9), LGE (n=9) and T1 mapping (n=7). For analysis of T2WI an edema ratio (ER; i.e. the signal intensity ratio between myocardium and reference skeletal muscle) > 2.0 was considered indicative of edema. Post-processing comprised native T1 measurements in three regions of the ablation line (near the tricuspid annulus, mid region, near the caval vein) on pre- and post-ablation images by two independent observers. For each region, the change in T1 value was expressed as the absolute increase (in ms) and the relative increase (in %). A third observer, blinded to the CMR results, reviewed which region(s) had required additional RF lesions after post-ablation CMR imaging. Results In 12 out of 13 patients CMR-guided atrial flutter ablation was successful, resulting in bidirectional conduction block. In 1 patient the ablation procedure was completed in the conventional electrophysiology lab, hampering acute post-ablation imaging. In all patients T2WI demonstrated edema in the ablation region. The ER increased from 1.6 ± 0.3 to 3.3 ± 0.5 post-ablation (p<0.001). Perfusion defects were present in 9/9 patients. The LGE images demonstrated hyperenhancement with a central area of hypo-enhancement in 9/9 patients, suggestive of ablation necrosis and previously reported areas of microvascular damage and hemorrhage. Right atrial T1 mapping was feasible in 20/21 regions (in 1 case artifacts from the adjacent catheter hampered analysis) and reproducible (r 0.981, ICC 0.939). The post-ablation increase in T1 value was significantly different between regions that did (n=10) and did not (n=10) require additional RF lesions, T1 increase was 46 ± 90ms versus 133 ± 69ms (p = 0.026), and 4.7 ± 9.1% versus 13.2 ± 6.8% (p = 0.028) respectively. Conclusion CMR tissue characterisation of acute ablation lesions during CMR-guided atrial flutter ablation demonstrates edema, perfusion defects, and necrosis with a core of microvascular damage. Atrial T1 mapping of the acute ablation lesion is feasible and reproducible, and might distinguish regions that require additional RF applications.

Implementation of Wireless Backhaul and Inter-Tower Communications With MIMO in ATSC 3.0

Wireless backhaul, i.e., in-band distribution links (IDL) and inter-tower communications networks (ITCN) were previously proposed as key enabling technologies for the next-generation digital broadcasting systems, e.g., the Advanced Television Systems Committee (ATSC) 3.0 system. Both ITCN/IDL can be operated in the spectrum-efficient in-band full-duplex (IBFD) mode and the same frequency band is shared between the broadcast service signal and the ITCN/IDL signals. It is desirable to integrate multi-input multi-output (MIMO) into ITCN/IDL transmission to increase the throughput and reduce the portion of spectrum occupation by ITCN/IDL. However, due to the backward compatibility constraint, conventional symmetrical MIMO techniques cannot be applied directly to the existing broadcast infrastructure without affecting legacy receivers. In this paper, the practical implementation of a non-symmetrical MIMO for ITCN/IDL while maintaining backward compatibility is considered. In addition to the existing broadcasting antenna, the non-symmetrical MIMO comprises an additional low-power RF feeder cable and one or more highly directional antennas to achieve low-cost MIMO implementation for high throughput data distribution and inter-tower communications. When the broadcast service signal and the MIMO signal are multiplexed in Time Division Multiplexing (TDM) format, the signal structure is ATSC 3.0 standard compliant. When the broadcast service signal and the MIMO signal are multiplexed in Layer Division Multiplexing (LDM) format, modification of the ATSC 3.0 standard, i.e., introducing a new pilot encoding scheme, is required. Moreover, MIMO self-interference cancellation (SIC) is investigated for IBFD operation.

AB-452663-3 DISTRIBUTION OF TRIGGERS IN THE LEFT ATRIAL POSTERIOR WALL IN AF PATIENTS UNDERGOING CATHETER ABLATION

Having a common embryologic origin with the pulmonary veins (PVs), left atrial posterior wall (LAPW) is considered to be a source of non-PV triggers that facilitate maintenance of atrial fibrillation (AF). However, the benefits of electrical isolation of the posterior wall (PWI) is still debated with contradictory data originating from different ablation approaches. . We report the distribution of triggers in the LAPW area in AF patients undergoing repeat ablation. Consecutive AF patients undergoing catheter ablation between 2015 and 2022 were included in this analysis. PVs were isolated first. Next, high-dose isoproterenol challenge (up to 30μg/min) was used to disclose triggers in the PW by moving the circular mapping catheter along the PW down to the level of coronary sinus, which were targeted using additional RF energy. We defined lower part of LAPW as the area between the line joining the inferior borders of the inferior PV-encircling lesions and the coronary sinus. The endpoint was to achieve electrical isolation, as documented by absence of any electrical activity in the PW. Of the 10,390 AF ablations performed during the specified time period, 5843 (56.2%) had triggers mapped and ablated in the LAPW area. Triggers were seen to be originating from the part of the PW between the PVs in 3809 (65.2%), from the lower part of the PW in 2028 (34.7%) and focal triggers from all over the PW including the lower part in 1519 (26%) cases. All triggers were targeted for ablation. Figure 1 demonstrates the triggers arising from lower PW. Ectopic triggers in the LAPW were documented to be arising from the lower part of the PW in a large number of cases. Thus, operators should consider extending the ablation to include the lower LAPW area to maximize the benefits of PWI.

Rydberg-State Engineering: Investigations of Tuning Schemes for Continuous Frequency Sensing

On-resonance Rydberg atom--based radio-frequency- (rf) electric-field sensing methods remain limited by the narrow frequency-signal detection bands available from resonant transitions. An additional rf tuner field can be used to dress or shift a target Rydberg state to return a detuned signal field to resonance and thus dramatically extend the frequency range available for resonant sensing. Here we investigate three distinct tuning-level schemes based on adjacent Rydberg transitions, which are shown to have distinct characteristics and can be controlled with the frequency or the strength of the tuning field. We further show that a two-photon Raman peak can be used as an effective tuning feature separate from conventional Autler-Townes splitting. We compare our tuning schemes with ac Stark effect--based broadband rf-field sensing and show that although the sensitivity is diminished with tuning away from a resonant state, it nevertheless can be used in configurations where there is a low density of Rydberg states, which would result in a weak ac Stark effect.

Agronomic Practices Alter Regulated Effects of Easily Extractable Glomalin-Related Soil Protein on Fruit Quality and Soil Properties of Satsuma Mandarin

Easily extractable glomalin-related soil protein (EEG) released from arbuscular mycorrhizal fungi exhibits many roles in soil and plants, while it is not clear whether the biostimulator alone or in combination with agronomic practices can improve soil characteristics and fruit quality in citrus. The objective of this study was to analyze the effects of foliar sprays of EEG, singly or in combination with fruit bagging (FB), reflective film mulching (RF), and grass-proof cloth mulching (GPC) on root mycorrhizal colonization rate, fruit internal and external quality, and soil structure and fertility on an early-ripening Satsuma mandarin “Oita 4” (Citrus unshiu cv. Oita 4). Exogenous EEG application increased root mycorrhizal colonization, while agronomic practices dramatically inhibited root mycorrhizal colonization in EEG-treated trees. Foliar EEG application significantly improved the internal and external quality of fruits, but the combination of three agronomic practices with EEG did not further enlarge the improved effect on the external quality of fruit and even produced an inhibitory effect. Also, the addition of RF further amplified the improved effect of EEG on the contents of fruit vitamin C and soluble solids. EEG application also significantly elevated sucrose in the fruit pith and juice sac, fructose in the fruit peel, fruit pith, segment membrane, and juice sac, and glucose in the fruit pith, segment membrane, and juice sac. Additional RF treatment could increase sucrose in the fruit peel and juice sac as well as glucose in the fruit peel to varying degrees in EEG-treated trees. EEG application also significantly increased soil organic carbon, mean weight diameter, nitrate nitrogen, ammonium nitrogen, available phosphorus, and available potassium levels, with additional agronomic practices almost reducing the promoting effect of EEG on these soil variables. It has been summarized that a single EEG application had positive effects on fruit quality and soil fertility, while the additional agronomic practices resulted in little change or even suppressed the positive effects of EEG.

Development of an Add-on 23Na-MRI Radiofrequency Platform for a 1H-MRI System Using a Crossband Repeater: Proof-of-concept.

23Na-MRI provides information on Na+ content, and its application in the medical field has been highly anticipated. However, for existing clinical 1H-MRI systems, its implementation requires an additional broadband RF transmitter, dedicated transceivers, and RF coils for Na+ imaging. However, a standard medical MRI system cannot often be modified to perform 23Na imaging. We have developed an add-on crossband RF repeater system that enables 23Na-MRI simply by inserting it into the magnet bore of an existing 1H MRI. The three axis gradient fields controlled by the 1H-MRI system were directly used for 23Na imaging without any deformation. A crossband repeater is a common technique used for amateur radio. This concept was proven by a saline solution phantom and in vivo mouse experiments. This add-on RF platform is applicable to medical 1H MRI systems and can enhance the application of 23Na-MRI in clinical usage.

The association between autoantibodies and risk for venous thromboembolic events among patients with rheumatoid arthritis.

To assess the association between venous thromboembolic (VTE) events and autoantibodies, following patients from RA diagnosis, measuring occurrence, levels and collective load of different autoantibodies against post-translational protein modifications, in particular recognizing citrullination (e.g. citrullinated fibrinogen) and RF by isotype. A cohort of 2814 patients with newly diagnosed RA were followed for incident VTE through register linkages. Sera from RA diagnosis were centrally analysed for antibodies to second generation cyclic citrullinated peptides (anti-CCP2), 20 anti-citrullinated protein antibody (ACPA) fine-specificities, antibodies to additional protein modifications (carbamylation and acetylation) and RF by isotype. Association between baseline serology status and future VTE was analysed using Cox regression adjusted for age, sex and calendar period of RA diagnosis, overall and stratified by anti-CCP2 and RF positivity. During a median 16 years of follow-up, 213 first-ever VTE events were registered (5.0/1000 person-years). IgG anti-CCP2 (present in 65% of cohort) associated with VTE (hazard ratio [HR] = 1.33, 95% CI: 1.00, 1.78), in a dose-response manner. The risk of VTE increased with number of ACPA fine-specificities. IgM RF, but no other RF isotypes, associated with VTE (HR = 1.38, 95% CI: 1.04, 1.82). The associations were independent from smoking and HLA-DRB1 shared epitope alleles. None of the carbamylated or acetylated antibody reactivities associated with VTE. Anti-CCP2, load of ACPA fine-specificities and IgM RF at RA diagnosis are associated with an increased risk of future VTE in RA. Antibodies to citrullinated fibrinogen did not differ substantially from other ACPA fine-specificities. Autoreactivity to other post-translational modifications was not associated with VTE risk.

Assessment of SAR in Road-Users from 5G-V2X Vehicular Connectivity Based on Computational Simulations.

(1) Background: Cooperative Intelligent Transportation Systems (C-ITS) will soon operate using 5G New-Radio (NR) wireless communication, overcoming the limitations of the current V2X (Vehicle-to-Everything) wireless communication technologies and increasing road-safety and driving efficiency. These innovations will also change the RF exposure levels of pedestrians and road-users in general. These people, in fact, will be exposed to additional RF sources coming from nearby cars and from the infrastructure. Therefore, an exposure assessment of people in the proximity of a connected car is necessary and urgent. (2) Methods: Two array antennas for 5G-V2X communication at 3.5 GHz were modelled and mounted on a realistic 3D car model for evaluating the exposure levels of a human model representing people on the road near the car. Computational simulations were conducted using the FDTD solver implemented in the Sim4Life platform; different positions and orientations between the car and the human model were assessed. The analyzed quantities were the Specific Absorption Rate on the whole body (SARwb), averaged over 10 g (SAR10g) in specific tissues, as indicated in the ICNIRP guidelines. (3) Results: the data showed that the highest exposure levels were obtained mostly in the head area of the human model, with the highest peak obtained in the configuration where the main beam of the 5G-V2X antennas was more direct towards the human model. Moreover, in all configurations, the dose absorbed by a pedestrian was well below the ICNIRP guidelines to avoid harmful effects. (4) Conclusions: This work is the first study on human exposure assessment in a 5G-V2X scenario, and it expands the knowledge about the exposure levels for the forthcoming use of 5G in connected vehicles.

Microwave photonics analog link based on two integrated D-DPMZM linearized signals and with eliminated odd harmonics and all IMD’s

In this paper a novel Microwave Photonics Analog Link (MPAL) system configuration based on two Dual-drive Dual-parallel Mach–Zehnder modulators (D-DPMZMs) and two Balanced Photo-Detectors (BPDs) is developed and system performance parameters are optimised for Radio over Fibre (RoF) high-speed transmissions. The Intermodulation Distortions (IMDs), as well as the harmonic distortions have been eliminated. The proposed linearization of RF signal configuration is double side banded in both D-DPMZM. A detailed mathematical system modelling is developed for the proposed RoF system configuration, benchmarked against newly generated system simulations, and implemented utilising particular device characteristics derived from experimental work. The proposed Microwave Photonic Link (MPL) system uses fewer RF shifters and is easier to implement in actual applications since all of the system's commercially available off-the-shelf components have already been experimentally demonstrated. The RF linearization for this configuration has been tested by introducing an additional RF signal, as well as phase and intensity errors in MZ branches. The proposed novel linearized MPAL with high spurious free dynamic range would have a great impact on future aerospace, radar, defense and satellite-to-ground downlink communication systems applications.

Dual-mode microresonators as straightforward access to octave-spanning dissipative Kerr solitons

The Kerr soliton frequency comb is a revolutionary compact ruler of coherent light that allows applications from precision metrology to quantum information technology. The universal, reliable, and low-cost soliton microcomb source is key to these applications. As a development and extension of the direct creation of a soliton microcomb with the dual-mode scheme in an aluminum nitride microresonator, this paper thoroughly presents the design strategy to reliably attain such dual-modes in the silicon nitride (Si3N4) platform, separated by ∼10 GHz, which stabilizes soliton formation without using additional auxiliary laser or RF components. We demonstrate the deterministic generation of the refined single-solitons that span 1.5-octaves, i.e., near 200 THz, via adiabatic pump wavelength tuning. The ultra-wide soliton existence range up to 17 GHz not only suggests the robustness of the system but will also extend the applications of soliton combs. Moreover, the proposed scheme is found to easily give rise to multi-solitons as well as the soliton crystals featuring enhanced repetition rate (2 and 3 THz) and conversion efficiency greater than 10%. We also show the effective thermal tuning of mode separation to increase the possibility to access the single-soliton state. Our results are crucial for the chip-scale self-referenced frequency combs with a simplified configuration.

Contact force-controlled high power short duration radiofrequency ablation enables efficient creation of roof line and anterior mitral line in course of low voltage areas

Abstract Funding Acknowledgements Type of funding sources: None. Background Linear ablation lines in the left atrium are questionable for treatment of atrial fibrillation (AF). In particular they are challenging, performed with limited success rate and are arrhythmogenic due to recurrence of conduction. Contact force (CF)-controlled high power short duration (HPSD) radiofrequency ablation (RFA) in areas of fibrosis may overcome these limitations. Purpose We investigated the efficiency of contact force (CF)-controlled high power short duration (HPSD) radiofrequency ablation (RFA) for creation of linear lines in case of fibrotic areas in the anterior left atrium. Methods In 530 consecutive patients (pts), age 65±9 years, paroxysmal AF in 45%, persistent AF in 55%, AF-re-ablation in 32% of pts, undergoing HPSD CF-controlled RF ablation of AF. Besides from pulmonary vein isolation (PVI) additional left atrial linear ablation in the anterior left atrium was performed in 28% of patients exclusively in case of low voltage areas in the course of the line or in case of re-ablation of prior performed lines. Fibrosis was defined by areas of less than 0.5mV signals in high density 3D microelectrode mapping. More than 5% low voltage was present in 46% of pts and more than 20% low voltage in 27% of pts. HPSD RF ablation was performed using a power of 50 Watt, duration 5-15s, with CF-controlled catheters, seeking for CF of 10-30g, and an interlesion distance of 6mm. Results A anterior roof line between both upper pulmonary veins was performed in 25% of pts (n=133), and an anterior mitral line in 17% of pts (n=88). The anterior mitral line connected the superior mitral anulus with left upper, right upper PV or anywhere this the roof line depending on the distribution of low voltage areas. Overall success rate of bidirectional conduction block at the roof line was 92% and at the mitral line 94%. After remapping of gaps and re-ablation with conventional 35-40 Watt RF application of unlimited duration, success rate at the roof line improved to 98% and at the mitral line to 97%. No serious complications were associated with creation of these lines, especially, no pericardial tamponade occurred. Limited follow up will presented at the time of presentation. Conclusions CF-controlled creation of ablation lines in the anterior left atrium (roof line and anterior mitral line) by HPSD RF ablation is very efficient and safe in case of areas of low voltage in the course of the linear ablation. In rare cases additional conventional RF application of unlimited duration becomes necessary to complete the lines supported by identification of gaps by high density 3D microelectrode mapping. This approach has the potential to improve efficacy of AF ablation in patients with atrial fibrosis. The hypothesis have to be proven by a prospective controlled study in the near future.

Evaluation of a New DC-Ion Funnel Drift Tube for Use in Proton Transfer Reaction Mass Spectrometry.

We have developed and characterized a novel drift tube called the direct current-ion funnel (DC-ion funnel) drift tube, consisting of 20 traditional ring electrodes and 5 new DC-focusing electrodes (DC-FEs) for use in proton transfer reaction mass spectrometry (PTR-MS). Ion trajectory simulations demonstrate the ion focusing effect of the DC-FE and DC-ion funnel drift tube. Further comparative experiments show that the PTR-MS with the novel DC-ion funnel drift tube has a higher sensitivity (3.8-7.3 times for the volatile organic compounds considered in this work) than the PTR-MS with a traditional drift tube. Different from conventional radiofrequency (rf) focusing methods, the DC-ion funnel drift tube can realize ion focusing with only a DC electric field and no additional rf power supply, which makes it especially suitable for instruments requiring miniaturization and low power consumption to improve detection sensitivity. In addition, the DC-ion funnel drift tube can easily be coupled to other types of mass spectrometers to increase their detection sensitivity.