An ideal direct imaging system entails a method to illuminate on command a single diffraction-limited region in a generally thick and turbid volume. The best approximation to this is the use of ...large-aperture lenses that focus light into a spot. This strategy fails for regions that are embedded deep into the sample, where diffraction and scattering prevail. Airy beams and Bessel beams are solutions of the Helmholtz Equation that are both non-diffracting and self-healing, features that make them naturally able to outdo the effects of distance into the volume but intrinsically do not allow resolution along the propagation axis. Here, we demonstrate diffraction-free self-healing three-dimensional monochromatic light spots able to penetrate deep into the volume of a sample, resist against deflection in turbid environments, and offer axial resolution comparable to that of Gaussian beams. The fields, formed from coherent mixtures of Bessel beams, manifest a more than ten-fold increase in their undistorted penetration, even in turbid milk solutions, compared to diffraction-limited beams. In a fluorescence imaging scheme, we find a ten-fold increase in image contrast compared to diffraction-limited illuminations, and a constant axial resolution even after four Rayleigh lengths. Results pave the way to new opportunities in three-dimensional microscopy.
This study evaluated the long-term efficacy of a standard antithrombotic strategy versus half-dose direct oral anticoagulation (DOAC) after Watchman implantation.
No consensus currently exists on the ...selection of the most effective antithrombotic strategy to prevent device-related thrombosis (DRT) in patients undergoing endocardial left atrial appendage closure.
After successful left atrial appendage closure, consecutive patients were prescribed a standard antithrombotic strategy (SAT) or long-term half-dose DOAC (hdDOAC). The primary composite endpoint was DRT and thromboembolic (TE) and bleeding events.
Overall, 555 patients (mean age 75 ± 8 years, 63% male; median CHA2DS2-VASc congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischemic attack or thromboembolism, vascular disease, age 65-74 years, sex category score 4 interquartile range (IQR): 3-6; median HAS-BLED hypertension, abnormal renal or liver function, stroke, bleeding, labile international normalized ratio, elderly, drugs or alcohol score 3 IQR: 2-4) were included. Patients were categorized into 2 groups (SAT: n = 357 vs hdDOAC: n = 198). Baseline clinical characteristics were similar between groups. The median follow-up duration was 13 months (IQR: 12-15 months). DRT occurred in 12 (2.1%) patients, all in the SAT group (3.4% vs 0.0%; log-rank P = 0.009). The risk of nonprocedural major bleeding was significantly more favorable in the hdDOAC group (0.5% vs. 3.9%; log-rank P = 0.018). The rate of the primary composite endpoint of DRT and TE and major bleeding events was 9.5% in SAT patients and 1.0% in hdDOAC patients (HR: 9.8; 95% CI: 2.3-40.7; P = 0.002).
After successful Watchman implantation, long-term half-dose DOAC significantly reduced the risk of the composite endpoint of DRT and TE and major bleeding events compared with a standard, antiplatelet-based, antithrombotic therapy.
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Rhythm control of persistent atrial fibrillation (AF) patients represents a challenge for the modern interventional cardiac electrophysiologist; as a matter of fact, there is still divergence ...regarding the best ablative approach to adopt in this population. Different investigational endpoints, variability of techniques and tools, significant technological evolution, and the lack of universally accepted pathophysiological models engendered a considerable heterogeneity in terms of techniques and outcomes, so much that the treatment of persistent subtypes of AF commonly still relies mainly on pulmonary vein (PV) isolation. The purpose of the present review is to report the current experimental and clinical evidence supporting the importance of mapping and ablating non‐PV triggers and describe our institutional approach for the ablation of nonparoxysmal AF.
Abstract Electrical motors are key components in the electrical transition required for greenhouse gas reduction programs. Future aircraft will certainly employ electrical motors for primary and ...secondary surface control, for landing gear and for other actuations such as high-lift systems, and they will also need electrical motors for propulsion. The motors pose the hardest challenge due to the high-power density required. Hybrid-Electric propulsion represents one of the most important topics in the aerospace industry and offers an opportunity to pursue the electrification change especially in light aircraft segments. The focus of this paper is the comparison among permanent magnet synchronous motors for Hybrid Light Aircraft propulsion with traditional and additive winding technologies.
As atoms and molecules condense to form solids, a crystalline state can emerge with its highly ordered geometry and subnanometric lattice constant. In some physical systems, such as ferroelectric ...perovskites, a perfect crystalline structure forms even when the condensing substances are non-stoichiometric. The resulting solids have compositional disorder and complex macroscopic properties, such as giant susceptibilities and non-ergodicity. Here, we observe the spontaneous formation of a cubic structure in composite ferroelectric potassium-lithium-tantalate-niobate with micrometric lattice constant, 10(4) times larger than that of the underlying perovskite lattice. The 3D effect is observed in specifically designed samples in which the substitutional mixture varies periodically along one specific crystal axis. Laser propagation indicates a coherent polarization super-crystal that produces an optical X-ray diffractometry, an ordered mesoscopic state of matter with important implications for critical phenomena and applications in miniaturized 3D optical technologies.
The SPARC_LAB Thomson source Vaccarezza, C.; Alesini, D.; Anania, M.P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2016, Letnik:
829
Journal Article
Recenzirano
The SPARC_LAB Thomson source is a compact X-ray source based on the Thomson backscattering process presently under its second phase of commissioning at the LNF. The electron beam energy ranges ...between 30 and 150MeV, the electrons collide head-on with the Ti:Sapphire FLAME laser pulse the energy of which ranges between 1 and 5J with pulse lengths in the 25 fs–10ps range, this provides an X-ray energy tunability in the range of 20–500keV, with the further capability to generate strongly non-linear phenomena and to drive diffusion processes due to multiple and plural scattering effects. The experimental results of the obtained X-ray radiation are presented.
Author Affiliation: (1) St. David's Medical Center, Austin, USA (2) Department of Clinical, Internal, Anesthesiology and Cardiovascular Sciences, Policlinico Universitario Umberto I, Sapienza ...University of Rome, Viale del Policlinico, 155- 00161, Rome, Italy (3) Montefiore Medical Center, Bronx, NY, USA (4) Azienda Ospedaliera-Universitaria Luigi Sacco, Milan, Italy (b) michele.magnocavallo@uniroma1.it Article History: Registration Date: 10/30/2020 Accepted Date: 10/30/2020 Online Date: 11/06/2020 Byline:
This meta-analysis systematically evaluated the outcome of pulmonary vein isolation (PVI) with and without focal impulse and rotor modulation (FIRM) ablation in patients with atrial fibrillation.
...Extensive literature search was performed for studies reporting outcomes of PVI alone and PVI+FIRM procedures. For PVI alone, only randomized trials conducted in the past 3 years reporting single-procedure off-antiarrhythmic drugs success rate at ≥12-month follow-up were included. In PVI+FIRM group, all published studies reporting single-procedure off-antiarrhythmic drugs success rate with at least 1-year follow-up were identified. Meta-analytic estimates were derived using DerSimonian and Laird random-effects models, and pooled estimates of success rate (95% confidence interval) were computed. Statistical heterogeneity was assessed using Cochran
test and
. Study quality was assessed using Newcastle-Ottawa Scale. Fifteen trials were included, 10 with PVI+FIRM (n=511, nonrandomized prospective design), and 5 with PVI-only trials (n=295, randomized trials). All patients in PVI-only trials had 100% nonparoxysmal atrial fibrillation, except 1 study, and no prior ablations. About 24% of PVI+FIRM population had paroxysmal atrial fibrillation. After 15.9±5.5 (median 12) months follow-up, the off-antiarrhythmic drugs pooled success rate was 50% in FIRM+PVI (95% confidence interval, 28%-72%) and 58% in PVI (95% confidence interval, 46%-71%). Difference in effect size between groups was not statistically significant (
=0.21). No significant heterogeneity (total or within group) was observed in this meta-analysis (negative
values considered equal to zero).
The overall pooled estimate did not show any therapeutic benefit of PVI+FIRM approach over PVI alone, which suggests the need to reevaluate the clinical use of FIRM ablation in atrial fibrillation.
Introduction
Atrial fibrillation (AF) and premature ventricular complexes (PVC) are common arrhythmias. We aimed to investigate AF prevalence in patients with PVC and its impact on PVC ablation ...outcomes.
Methods
Consecutive patients undergoing PVC ablation at a single institution between 2016 and 2019 were included and prospectively followed for 2 years. Patients with severe valvular heart disease, hyperthyroidism, malignancy, alcohol use disorder and advanced renal/hepatic diseases were excluded. Twelve‐lead electrocardiograms were used to diagnose AF and assess PVC morphology. All PVCs were targeted for ablation using 4‐mm irrigated‐tip catheters at standardized radiofrequency power guided by 3‐D mapping and intracardiac echocardiography. Patients were followed with remote monitoring, device interrogations and office visits every 6 months for 2 years. Detection of any PVCs in follow‐up was considered as recurrence.
Results
A total of 394 patients underwent PVC ablation and 96 (24%) had concurrent AF. Patients with PVC and AF were significantly older (68.2 ± 10.8 vs. 58.3 ± 15.8 years, p < .001), had lower LV ejection fraction (43.3 ± 13.3% vs. 49.6 ± 12.4%, p < .001), higher CHA2DS2‐VASc (2.8 ± 1.3 vs. 2.0 ± 1.3, p < .001) than those without. PVCs with ≥2 morphologies were detected in 60.4% and 13.7% patients with vs without AF (p < .001). At 2‐year follow‐up, PVC recurrence rate was significantly higher in patients with vs without AF (17.7% vs. 9.4%, p = .02).
Conclusion
AF was documented in 1/4 of patients undergoing PVC ablation and was associated with lower procedural success at long‐term follow‐up. This was likely attributed to older age, worse LV function and higher prevalence of multiple PVC morphologies in patients with concurrent AF.
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