Efficiency of dispersive wave generation from a dual-frequency beat signal.

The emission of dispersive waves (DWs) by temporal solitons can be described as a cascaded four-wave mixing process triggered by a pair of monochromatic continuous waves (CWs). We report experimental and numerical results demonstrating that the efficiency of this process is strongly and nontrivially affected by the frequency detuning of the CW pump lasers. We explain our results by showing that individual cycles of the input dual-frequency beat signal can evolve as higher-order solitons whose temporal compression and soliton fission govern the DW efficiency. Analytical predictions based on the detuning dependence of the soliton order are shown to be in excellent agreement with experimental and numerical observations.

Experimental dynamics of Akhmediev breathers in a dispersion varying optical fiber.

We investigate experimentally the dynamics of Akhmediev breathers in an optical fiber with a longitudinally tailored dispersion that allows to nearly freeze the breather evolution near their point of maximal compression. Our results are in good agreement with numerical simulations.

Real time noise and wavelength correlations in octave-spanning supercontinuum generation.

We use dispersive Fourier transformation to measure shot-to-shot spectral instabilities in femtosecond supercontinuum generation. We study both the onset phase of supercontinuum generation with distinct dispersive wave generation, as well as a highly-unstable supercontinuum regime spanning an octave in bandwidth. Wavelength correlation maps allow interactions between separated spectral components to be identified, even when such interactions are not apparent in shot-to-shot or average measurements. Experimental results are interpreted using numerical simulations. Our results show the clear advantages of dispersive Fourier transformation for studying spectral noise during supercontinuum generation.

Cascaded Bragg scattering in fiber optics.

We report on a theoretical and experimental study of cascaded Bragg scattering in fiber optics. We show that the usual energy-momentum conservation of Bragg scattering can be considerably relaxed via cascade-induced phase-matching. Experimentally we demonstrate frequency translation over six- and 11-fold cascades, in excellent agreement with derived phase-matching conditions.

Hydrodynamic supercontinuum.

We report the experimental observation of multi-bound-soliton solutions of the nonlinear Schrödinger equation (NLS) in the context of hydrodynamic surface gravity waves. Higher-order N-soliton solutions with N=2, 3 are studied in detail and shown to be associated with self-focusing in the wave group dynamics and the generation of a steep localized carrier wave underneath the group envelope. We also show that for larger input soliton numbers, the wave group experiences irreversible spectral broadening, which we refer to as a hydrodynamic supercontinuum by analogy with optics. This process is shown to be associated with the fission of the initial multisoliton into individual fundamental solitons due to higher-order nonlinear perturbations to the NLS. Numerical simulations using an extended NLS model described by the modified nonlinear Schrödinger equation, show excellent agreement with experiment and highlight the universal role that higher-order nonlinear perturbations to the NLS play in supercontinuum generation.

Cascaded phase matching and nonlinear symmetry breaking in fiber frequency combs.

We report theoretical, numerical, and experimental studies of cascaded phase matching in fiber frequency combs and show how this mechanism is directly connected to the dynamics of supercontinuum generation. In particular, linking cascaded four-wave mixing with direct higher-order nonlinear processes allows us to derive a simple phase matching condition that governs nonlinear symmetry breaking in the presence of higher-order dispersion. We discuss how this mechanism provides a physical interpretation of soliton-induced Cherenkov radiation and associated spectral recoil in terms of phase-matched frequency mixing pumped by bichromatic pump pairs in the soliton spectrum. Theoretical and numerical predictions are confirmed via experiments using both quasicontinuous wave and picosecond pulse excitation.

Diagnosis and management of heart failure from hospital admission to discharge: A practical expert guidance.

Heart failure (HF) has high event rates, mortality, and is challenging to manage in clinical practice. Clinical management is complicated by complex therapeutic strategies in a population with a high prevalence of comorbidity and general frailty. In the last four years, an abundance of research has become available to support multidisciplinary management of heart failure from within the hospital through to discharge and primary care as well as supporting diagnosis and comorbidity management. Within the hospital setting, recent evidence supports sacubitril-valsartan combination in frail, deteriorating or de novo patients with LVEF≤40%. Furthermore, new strategies such as SGLT2 inhibitors and vericiguat provide further benefit for patients with decompensating HF. Studies with tafamidis report major clinical benefits specifically for patients with ATTR cardiac amyloidosis, a remaining underdiagnosed and undertreated disease. New evidence for medical interventions supports his bundle pacing to reduce QRS width and improve haemodynamics as well as ICD defibrillation for non-ischemic cardiomyopathy. The Mitraclip reduces hospitalisations and mortality in patients with symptomatic, secondary mitral regurgitation and ablation reduces mortality and hospitalisations in patients with paroxysmal and persistent atrial fibrillation. In end-stage HF, the 2018 French Heart Allocation policy should improve access to heart transplants for stable, ambulatory patients and, mechanical circulatory support should be considered to avoid deteriorating on the waiting list. In the community, new evidence supports that improving discharge education, treatment and patient support improves outcomes. The authors believe that this review fills the gap between the guidelines and clinical practice and provides practical recommendations to improve HF management.

Giant enhancement of second-harmonic generation in multiple diffraction orders from sub-wavelength resonant waveguide grating.

We demonstrate a purely dielectric resonant waveguide structure that enhances the efficiency of second-harmonic generation by a factor of at least 5500 compared to a flat reference surface in the same geometry. We also show that the structure emits second-harmonic radiation in four different directions when the sample is illuminated with fundamental radiation incident at the resonant angle of the sample.

Giant dispersive wave generation through soliton collision.

We numerically study long pulse supercontinuum generation in a photonic crystal fiber with two zero-dispersion wavelengths, reporting a dynamical effect where soliton collisions excite dispersive waves with 1 order of magnitude greater peak power than that arising from single-soliton generation. The dispersive wave peak power exhibits extreme-value "rogue" characteristics, with the long tail of the distribution populated by collision-related events.

Scimitar syndrome with bicuspid aortic valve. A case report of cross-sectional non- invasive imaging allowing a complete anatomical and functional assessment.

Scimitar syndrome is a variant of partial anomalous pulmonary venous return with an aberrant vein, the Scimitar vein, draining the right lung to the inferior vena cava instead of the left atrium, resulting in a left-to-right shunt. The classic frontal radiographic finding, designated as "the scimitar sign", is of a scimitar (a Turkish sword) shaped density along the right cardiac border. The diagnosis can be made by echocardiography, and cardiac catheterisation remains the gold standard to assess the left-to-right shunt. However, the place of multimodal cardiac imaging by computed tomography and magnetic resonance imaging is increasing. We report the case of a 26 year-old man presenting with chest pain during a brief panic attack, in whom scimitar syndrome was associated with a bicuspid aortic valve, a clinical association rarely reported in the literature. CT and MRI cardiac imaging was as accurate as echocardiography and hemodynamics, particularly for shunt quantification.

Modulation instability, Akhmediev Breathers and continuous wave supercontinuum generation.

Numerical simulations of the onset phase of continuous wave supercontinuum generation from modulation instability show that the structure of the field as it develops can be interpreted in terms of the properties of Akhmediev Breathers. Numerical and analytical results are compared with experimental measurements of spectral broadening in photonic crystal fiber using nanosecond pulses.

Rogue-wave-like characteristics in femtosecond supercontinuum generation.

We experimentally study the characteristics of optical rogue waves in supercontinuum generation in the femtosecond regime. Specifically, the intensity histograms obtained from spectrally filtering the supercontinuum exhibit the L-shaped characteristics typical of extreme-value phenomena on both the long-wavelength and short-wavelength edges of the spectrum owing to cross-phase modulation and soliton-dispersive wave coupling. Furthermore, the form of the histogram on the long-wavelength edge varies from L-shaped to quasi-Gaussian as wavelengths closer to the pump are included in the filtered measurements. Our observations are in agreement with numerical simulations.

Nonlinear envelope equation modeling of sub-cycle dynamics and harmonic generation in nonlinear waveguides.

We describe generalized nonlinear envelope equation modeling of sub-cycle dynamics on the underlying electric field carrier during one-dimensional propagation in fused silica. Generalized envelope equation simulations are shown to be in excellent quantitative agreement with the numerical integration of Maxwell's equations, even in the presence of shock dynamics and carrier steepening on a sub-50 attosecond timescale. In addition, by separating the effects of self-phase modulation and third harmonic generation, we examine the relative contribution of these effects in supercontinuum generation in fused silica nanowire waveguides.

[Variations of radiation dosage delivered to patients undergoing interventional cardiological procedures. A monocentric study 2002-05]. / Variations des doses de rayonnements délivrées au patient en cardiologie interventionnelle. Etude monocentrique 2002-2005.

X-ray exposure of patient during coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) may have some deleterious effects. The dose area product (DAP), related to the effective dose, is a measure of stochastic risk and a potential quality indicator. The aim of our study was to assess radiation exposure of patients in a large series of "real life" interventional cardiac procedures. We evaluated DAP and Fluoroscopy time (t) during CA and/or PTCA in 3600 consecutive patients from 2002 to 2005. Procedures were performed by five experienced physicians, using successively femoral and radial techniques. DAP and t significantly correlated (r = 0.73; p < 0.0001). Median [25th-75th percentiles] values for DAP and for t were 63 [40-101] Gy.cm2 and 6.3 [4-10] min for CA, 100 [62-178] Gy.cm2 and 14.0 [9-22] min for elective PTCA, and 141 [90-219] Gy.cm2 and 15.7 [11-23] min for CA immediately followed by ad hoc PTCA, respectively. Differences between operators ranged from 50% (CA) to 70% (PTCA) for both DAP and t (p < 0.001). Moving from the femoral to the radial approach resulted in a 1.5 to 2-fold increase in DAP in 2002 (p < 0.001). DAP and t then decreased toward the european DIMOND reference values (in 2005: 53.4 Gy.cm2 and 5.5 min for CA, 104.64 Gy.cm2 and 13.1 min for elective PTCA, 128.4 Gy.cm2 and 13.6 min for ad hoc PTCA). In conclusion, radiation exposure to patients and staff are strongly dependent on operators, time course, and the arterial access, due in part to the learning curve for radial approach. The enhanced knowledge of radiation dose is the first step of a radiation dose-reduction program, likely to minimize patient and operator radiation hazards in interventional cardiology. Definition of national reference values for DAP and fluoroscopy time would be helpful for appropriate comparisons.

[Complicated transcatheter aortic-valve endocarditis with abscess and pseudoaneurysm: Value of the ECG-gated multidetector computed tomography angiography]. / Endocardite infectieuse sur TAVI compliqué d'abcès et pseudo-anévrysme : apport du scanner cardiaque synchronisé à l'ECG.

A 80-year-old man was admitted to catheterization room for an acute infero-lateral ST-elevation myocardial infarction (STEMI). Coronary angiography showed a thrombotic occlusion of the second left marginal branch, and normal other coronary arteries. The thrombo-embolic mechanism of the STEMI, and the infectious context in this patient who had had a transcatheter aortic valve implantation (TAVI) two months earlier, led us to suspect a bioprosthesis endocarditis. It was confirmed by transthoracic and transoesophageal echocardiography, which showed an aortic-mitral curtain abscess and aortic bioprosthesis vegetations, associated to Enterococcus faecalis bacteriemia. In order to specify the diagnosis, an ECG-gated multidetector CT angiography (MDCTA) had been performed. Additionally to echocardiographic findings, MDCTA showed a pseudo-aneurysm, sized 20 to 22mm, beginning from the outflow tract of the left ventricle to end on the antero-lateral face of the aorta. The patient was referred for emergency aortic bioprosthesis removal and replacement. Through this case, MDCTA showed its importance for the diagnosis and the prognostic evaluation of cardiac prosthesis endocarditis. MDCTA provided additional informations that echocardiography could not detect, because of artifacts caused by the prosthetic material and calcifications, frequent in elderly patients with comorbidities.

Immediate coronary angiography in survivors of out-of-hospital cardiac arrest without obvious extracardiac cause: Who benefits?

BACKGROUND: Immediate coronary angiography (iCA) and primary percutaneous coronary angioplasty (pPCI) in patients successfully resuscitated after out-of-hospital cardiac arrest (OHCA) of suspected cardiac cause is controversial. Our aims were to assess the results of iCA, the prognostic impact of pPCI after OHCA, and to identify subgroups most likely to benefit from this strategy. METHODS: In this single-centre retrospective study, patients aged ≥18 years with sustained return of spontaneous circulation after OHCA and no evidence of a non-cardiac cause underwent routine iCA at admission, with pPCI if indicated. Results of iCA, and factors associated with in-hospital survival were analysed. RESULTS: Between 2006 and 2013, 160 survivors from OHCA presumed of cardiac origin were included (median age, 60 years; 85% males). iCA showed significant coronary-artery lesions in 75% of patients, and acute occlusion or unstable lesion in only 41%. pPCI was performed in 34% of patients and was not associated with survival by univariate or multivariate analysis (P=0.67). ST-segment elevation predicted acute coronary occlusion in 40%. An initial shockable rhythm was associated with higher in-hospital survival (52% vs. 19%; P<0.001). After initial defibrillation, the first rhythm recorded by 12-lead electrocardiography was highly associated with prognosis: secondary asystole had a very low survival rate (5%, 1/21) despite PCI in 43% of patients, compared to sustained ventricular tachycardia/fibrillation (42%, 15/36) and supraventricular rhythm (71%, 50/70) (P<0.001). CONCLUSIONS: In our experience, the prevalence of acute coronary occlusion or unstable lesion immediately after OHCA of likely cardiac cause is only 41%. Immediate CA in OHCA survivors, with pPCI if indicated, should be restricted to highly selected patients.

Supercontinuum generation by nanosecond dual-wavelength pumping in microstructured optical fibers.

We study experimentally the spectral evolution of supercontinua in two different microstructured fibers that are pumped with nanosecond pulses from dual-wavelength sources of either 1064/532 nm or 946/473 nm output. The experimental findings are compared with simulations based on numerically solving the nonlinear Schrödinger equation. The role of cascaded cross-phase modulation processes and the group-delay properties of the fiber are emphasized and demonstrated to determine the extent of the broadening of the continua to the visible wavelengths.

[Intracoronary administration of antithrombotic agents via a perfusion balloon catheter in patients with ST-segment elevation myocardial infarction presenting with massive intraluminal thrombus and failed aspiration]. / Apport de l'administration intracoronaire d'antithrombotiques par cathéter à ballon de perfusion en phase aiguë d'infarctus du myocarde avec thrombus massif et échec de la thromboaspiration.

BACKGROUND: Massive intracoronary thrombus is associated with adverse procedural results including failed aspiration and unfavourable reperfusion. We aim to evaluate the effect of the intracoronary administration of antithrombotic agents via a perfusion catheter in patients with ST-segment elevation myocardial infarction (STEMI) presenting with a large thrombus burden and failed aspiration. METHODS: We retrospectively analyzed the thrombus burden, the TIMI grade flow, and the myocardial Blush in 25 consecutive STEMI patients with a large thrombus burden and failed manual aspiration, who received intracoronary infusion of glycoprotein IIb/IIIa inhibitors (N=17) or bivalirudine (N=8) via a 6F-infusion catheter (ClearWay™ RX) RESULTS: Mean age was 67±14 years, 16 patients (64 %) presented with anterior STEMI, and 7 (28 %) with cardiogenic shock. Immediately after intracoronary infusion, the TIMI flow grade improved of 2 grades in 7 patients (28 %), and 1 grade in 14 (56 %), a complete resolution of the thrombus was observed in 9 patients, and a >50 % resolution in 12. Blush was improved of 3 grades in 15 patients (60 %), of 2 grades in 7 (28 %), and Blush grade 0 remained in 3. At the end of procedure, we observed normal TIMI 3flow in most patients (92 %), a complete resolution of thrombus in 80 %, and a Blush grade 3 in 68 %. CONCLUSIONS: In STEMI patients presenting with a large thrombus burden and failed aspiration, intracoronary administration of glycoprotein IIb/IIIa inhibitors or bivalirudin via the perfusion catheter ClearWay™ RX significantly reduced the thrombus burden and improved the TIMI flow and the Blush grade, without bleeding.

Supercontinuum generation in large mode-area microstructured fibers.

Supercontinuum generation in large mode-area microstructured fibers is demonstrated by launching into the fiber ns pulses from a passively Q-switched Nd:YAG laser. The special properties of these fibers open the way to compact, single-mode, high-power supercontinuum sources with a low divergence of the output beam. The nonlinear phenomena leading to the formation of the broad spectrum are also described.

[Coronary stent evaluation with cardiac CT: Literature review]. / Évaluation des stents coronaires en scanner cardiaque: revue de la littérature.

Since the introduction of the 64-generation scanners, the accuracy and robustness of the diagnosis of coronary artery disease has progressed. The main advantage of cardiac CT is the exclusion of coronary artery disease by its excellent negative predictive value. Currently, cardiac CT applications extend thanks to innovations both in terms of technological development systems scanner or stents implanted. This is a literature review of stent evaluation with cardiac CT.