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Objective: The role of left ventricular (LV) volumes and ejection fraction (EF) in the selection of patients for the MitraClip procedure remains matter of debate. The goal of this study is to assess the pattern of LV remodeling and its clinical implications after MitraClip procedures, and to evaluate the role of LV ejection fraction (EF) in patient selection. Methods: Complete echocardiography was performed before, at discharge, 1,6, and 12-months in 45 patients treated with MitraClip for severe mitral regurgitation (MR) [age 78.2 ± 8.3 yrs, NYHA 3.74 ± 0.44, EF 36.5 ± 12.8%]. From baseline to 6-month, reverse and adverse LV-R were defined as a ≥15% decrease in LV end-systolic volume and a ≥10% increase in LV end-systolic volume, respectively. Results: At 6-month, sustained reduction of MR ≤ 2 was observed in all patients, but two; reverse, adverse, and no LV-R occurred in 51% (N = 23), 18% (N = 8), and 31% (N = 14) of patients, respectively. Baseline LV end-diastolic volume was an independent predictor of reverse LV-R [P = 0.004], whereas EF was not. During follow-up (17.5 ± 9.3 months) period, 50% of adverse/no LV-R patients were free of the composite endpoint (mortality and hospitalization for heart failure) compared to 95.7% of reverse LV-R patients (P = 0.006). In Cox analysis, adverse LV-R and adverse/no LV-R were associated with composite endpoint with adjusted hazard ratios of 5.6 (95% CI 1.65-19.00) and 10.08 (95% CI 1.29–78.6), respectively. Conclusion: After MitraClip implantation, sustained adverse or no LV-R occurred in one-in-two patients and was associated with poor prognosis. Large LV volumes may help us to avoid the futility of the procedure.

Highly transparent 10 at.% Yb:GdxY3−xAl5O12 (x = 0.3, 0.5, and 0.7) ceramics were successfully fabricated by vacuum solid‐state reactive sintering at 1800°C for 20 h combined with hot isostatic pressing posttreatment at 1700°C for 3 h under 176 MPa pressure in Ar atmosphere. The in‐line transmittances of these ceramics with the thickness of 2.5 mm are 84.4%, 84.0%, and 83.5% at 1100 nm for x = 0.3, 0.5, and 0.7, respectively. The relationships of the Gd3+ content among the phase, microstructures, spectral, and laser properties of the Yb:GdxY3−xAl5O12 ceramics were elucidated in detail. The introduction of Gd3+ has a little influence on the crystal field strength of the Yb3+ sites in GdxY3−xAl5O12. The absorption, emission spectra, and fluorescence lifetime of the Yb3+ in these ceramics are similar, close to 10 at.% Yb:YAG ceramics. Quasi‐continuous wave laser outputs of the ceramics were also achieved. The maximum laser output powers are 7.8, 7.7, and 6.6 W with the corresponding slope efficiency as 46.2%, 44.7%, and 39.2% for x = 0.3, 0.5, and 0.7, respectively. The 7.8 W laser output power is the highest value achieved so far for the Yb:GdYAG ceramics, to the best of our knowledge. The previous discussions show that not all the mixed garnets could enhance full width at half maximum of absorption and emission peaks for the active ions; however, the Yb:GdYAG ceramics are still excellent laser gain media. [ABSTRACT FROM AUTHOR]

Background: Noninvasive imaging methods, either anatomical or functional tests, serve as essential instruments for the appropriate management of patients with established or suspected coronary artery disease (CAD). We sought to evaluate the safety and efficacy of a coronary computed tomography angiography (CCTA) plus stress cardiac magnetic resonance imaging (S-CMR) strategy in patients with chronic coronary syndrome (CCS). Methods: Patients with suspected CCS showing intermediate coronary plaques (stenosis 30–70%) at CCTA underwent S-CMR. Patients with a positive S-CMR were referred to invasive coronary angiography (ICA) plus instantaneous wave-free ratio (iFR), and myocardial revascularization if recommended. All patients received guideline-directed medical therapy (GDMT), including high-dose statins, regardless of myocardial revascularization. The primary endpoint was a composite of death from cardiovascular causes, non-fatal myocardial infarction, and unplanned revascularization. Results: According to the results of CCTA, 62 patients showing intermediate coronary plaques underwent S-CMR, which was positive for a myocardial perfusion deficit in n = 17 (27%) and negative in n = 45 (73%) patients. According to the results of ICA plus iFR, revascularization was performed in 13 patients. No differences in the primary endpoint between the positive and negative S-CMR groups were observed at 1 year (1 [5.9%] vs. 1 [2.2%], p = 0.485) and after a median of 33.4 months (2 [11.8%] vs. 3 [6.7%]; p = 0.605). Conclusions: Our study suggests that a CCTA plus S-CMR strategy is effective for the evaluation of patients with suspicion of CCS at low–intermediate risk, and it may help to refine the selection of patients with intermediate coronary plaques at CCTA needing coronary revascularization. [ABSTRACT FROM AUTHOR]

In this work, 5at.% Yb:Lu2O3 transparent ceramics were air‐annealed at different temperatures to eliminate oxygen vacancies for laser performance improvement. The influence of annealing temperature on microstructures, optical quality, and laser performance was investigated comprehensively. The ceramics HIP (Hot isostatic pressing) post‐treated at 1750°C and annealed above 1100°C show a significant optical quality decrease due to residual pore expansion, and the ceramic sample annealed at 900°C shows better laser performance than others. The maximum output of 2.88 W was obtained at 1033.3 nm with a slope efficiency of 37.4% under a quasi‐continuous wave (QCW) mode. Note that 5at.% Yb:Lu2O3 transparent ceramics HIP post‐treated at 1550°C still keep good transparency even when being annealed at 1300°C due to less residual compressed pores. The highest slope efficiency is about 73.8% with a maximum output power of 2.84 W under QCW. Fine‐grained and dense Yb:Lu2O3 transparent ceramics could be annealed at higher temperatures to eliminate oxygen vacancies more thoroughly to improve laser performance. [ABSTRACT FROM AUTHOR]

5at.% Yb:Lu2O3 transparent ceramics were fabricated successfully by vacuum sintering along with hot isostatic pressing posttreatment from the nanopowders. The influences of calcination temperature on morphology and microstructures of powders and ceramics were studied systematically. The optimal ceramic sample from the nanopowder calcined at 1050°C shows uniform and dense microstructure with the in‐line transmittance of 81.5% at 1100 nm. The results of the thermal measurements, that is, thermal conductivity and specific heat, were related to the changes occurring in the microstructure of the ceramics studied. It was shown on this basis that appropriate control of the technological process of sintering ceramics makes it possible to obtain laser ceramics with very good thermal properties as well as maintaining their high optical quality. Concerning the laser performance, the highest‐optical quality 5at.% Yb:Lu2O3 sample was pumped in quasi‐continuous wave conditions measuring a maximum output power of 2.59 W with a corresponding slope efficiency of 32.4%. [ABSTRACT FROM AUTHOR]

Some specifics of spectroscopic and laser properties of Yb3+ dopant are shown in Yb3+‐doped Lu2O3 cubic sesquioxide transparent ceramics, a very important laser material, fabricated by Akio Ikesue using the method based on solid‐state mixing of oxides and sintering by hot isostatic pressing (HIP) technique. For instance, despite the simplicity of Yb3+ electronic configuration, it is emphasized that a lot of precautions need to be considered during the evaluation and the assignment of Yb3+ experimental data in this sample and also in all Yb3+‐doped materials. First, we focus our discussion on the position of 2F7/2 (ground state) and 2F5/2 (excited state) Stark levels of the most populated C2 symmetry site, and on the presence of the magnetic dipole transitions from the C3i (S6) inversion symmetry site. Then, we point out the strong influence of the self‐trapping and the self‐quenching processes on the measurement of the 2F5/2(5) upper level decay time which needs the pin‐hole method. Finally, we comment on the spectrum of the tuneable laser emission behaviour near 1033 nm with respect to the losses of the laser cavity without the laser emission near 1080 nm, as observed in other laser materials. [ABSTRACT FROM AUTHOR]

Transparent 4 at.% Tm:Y3ScAl4O12 (Tm:YSAG) laser ceramics were fabricated by solid‐state reaction combined with vacuum sintering method. The 4 at.% Tm:YSAG ceramic sample sintered at 1800°C for 30 hours possesses homogenous microstructure and excellent optical properties, showing a transmittance of 79.3% at 2000 nm. The absorption and emission spectra of the Tm:YSAG ceramics are studied and compared with those of 4 at.% Tm:Y3Al5O12 ceramics. The introduction of Sc3+ greatly affects the energy levels of the Tm3+, causing the disappearance and degeneration of some absorption and emission peaks in the middle infrared region. The laser performance of the 4 at.% Tm:YSAG ceramics is also tested in the Quasi‐continuous‐wave (QCW) mode by pumping with a 790 nm laser diode (LD). A maximum laser output power of 0.54 W with a slope efficiency of 4.8% is achieved, which is the first laser output for Tm:YSAG ceramics. [ABSTRACT FROM AUTHOR]

Transparent Yb:Y3ScAl4O12 (Yb:YSAG) ceramics with different ytterbium doping concentrations such as 5, 10, 15, 20 at.% have been successfully fabricated by solid‐state reactive sintering. All the obtained ceramics are in dense and homogeneous structure after sintering at 1820°C for 30 hours and with a posttreatment by hot isostatic pressing at 1750°C for 3 hours with 200 MPa pressure. We systematically analyzed the influence of Yb3+ doping concentration on the microstructure and optical properties of the ceramics. The 10 at.% Yb:Y3ScAl4O12 ceramics with a thickness of 3.2 mm show the best transparency as high as 80.9% at 1100 nm. The laser emission of the 10 at.% Yb:YSAG ceramics was tested, resulting in a maximum slope efficiency of 67.6% and a maximum output power of 11.3 W under quasi‐continuous wave pump conditions. The tuning range spanned from 990 to 1071 nm. [ABSTRACT FROM AUTHOR]

In this article, 5 at.% Yb:Lu2O3 transparent ceramics were fabricated by vacuum sintering combined with hot isostatic pressing (HIP) posttreatment using co‐precipitated nano‐powders. The influence of precipitant molar ratio, ammonium hydrogen carbonate, to metal ions (AHC/M3+, R value) on the properties of Yb:Lu2O3 precursors and calcined powders was investigated systematically. It was found that the powders with different R value calcined at 1100°C for 4 hours were pure cubic Lu2O3 but the morphologies of precursors and powders behaved differently. The opaque samples pre‐sintered at 1500°C for 2 hours grew into transparent ceramics after HIP posttreatment at 1750°C for 1 hour. The final ceramic with R = 4.8 showed the best optical quality with the in‐line transmittance of 79.7% at 1100 nm. The quasi‐CW laser operation was performed at 1034 nm and 1080 nm with a maximum output power up to 8.15 W as well as a corresponding slope efficiency of 58.4%. [ABSTRACT FROM AUTHOR]

This paper is devoted to summarizing and discussing the scientific progress achieved during the past decade in diode-pumped ytterbium-doped solid-state lasers. The output radiation centered on the 1-μm region is of particular interest for the well-known applications of previously developed Nd3+ lasers. Several hosts have been studied and tested in recent years. Due to the enormous number of papers dealing with ytterbium, Yb 3+, doped hosts, we will limit our report here to materials based on transparent polycrystalline sesquioxide laser ceramics, such as Lu2O3, Sc2O3, and Y2O3. The reason is basically due to the wider emission band of ytterbium-doped sesquioxides as compared with more commonly used hosts such as YAG. The higher thermal conductivity with respect to hosts such as CaF2 makes them very interesting for applications requiring both good thermal conductivity and a wide fluorescence emission band, as well as for short pulse generation at high average power levels. Furthermore, the replacement of trivalent Yb in sesquioxides does not require any charge compensation (as is the for instance case of the replacement of divalent Ca in CaF2), which makes their fabrication easier, in particular at high doping levels. [ABSTRACT FROM AUTHOR]

Yb:YAG ceramic solid-state laser gain media have been of growing interest for high-repetition rate and high-power lasers during the last few years. A great advantage of ceramic technology compared with that of single crystals is the flexibility of shaping methods allowing the production of near-net-shape components with a well-defined internal structure. A favorable dopant distribution can enhance laser efficiency by mitigating thermal effects. The presented work reports on Yb:YAG transparent ceramics composed of layers with different Yb doping produced by two different shaping methods: dry pressing of spray-dried powders and tape casting, all sintered under high vacuum. The selected geometry of materials was based on numerical simulations. Optical quality of produced ceramics was characterized and discussed in connection with the microstructure and laser emission results. Output power of nearly 7 W and slope efficiency of 58.1% were obtained in quasi-continuous wave regime from bilayered 0% to 10% Yb:YAG. In the case of multilayered materials, higher scattering losses were observed. The comparison of the two processing methods highlighted that the tape-cast materials provided higher optical uniformity and the diffusion zone between the single layers with different dopant content was about 150 μm compared to about 250 μm in samples produced by pressing of powders. [ABSTRACT FROM AUTHOR]

Thermal effects in transparent laser crystals and ceramics are generally an unwanted consequence of the pumping process: temperature gradients give rise to an unevenly distributed refractive index variation and a distortion of the optical surfaces crossed by the laser beam (thermal lens); birefringence due to thermomechanical stress can cause depolarization losses; and absorption from the ground level usually increases with temperature in quasi-three-level systems. All these effects can seriously impair laser performance, especially in high-power devices. Layered structures with a tailored modulation of the doping level can be used to reduce the peak temperature, the temperature gradients and also the thermally induced deformation of the laser material, thus mitigating the overall thermal effects. In the present work, structures comprising two and three layers of different compositions (pure YAG/10 at% Yb:YAG and pure YAG/10 at% Yb:YAG/pure YAG) were designed with a view to control deformation and stresses, and to reduce the thermal lensing effect. The multilayered samples were assembled by linear and cold isostatic pressing, and co-sintered under a high vacuum in a clean-atmosphere furnace. The microstructure of the layered samples obtained was characterized by FEG SEM, ESEM and TEM. The Yb diffusion profile across the doped/undoped interface was identified and related to the laser's output power. An internal optical transmittance up to 96% was obtained. A laser output power up to 5 W, with a slope efficiency as high as 74.3%, was also achieved. [ABSTRACT FROM AUTHOR]

We present the performance of a laser prototype based on 1% at. Yb : Lu2O3 ceramic, longitudinally pumped in quasi-CW regime at 968 nm. A slope efficiency of 49% with respect to the absorbed pump power was obtained for laser operation at 1032.5 nm. We studied the effects on the laser oscillation due to the reinjection of the residual pump. The thermal behavior of the sample was investigated by means of numerical simulations, accounting for the different thermal load resulting from spontaneous and laser emission. Finally, we report the measured level of the Amplified Spontaneous Emission, which is found to be less than 0.1mW. [ABSTRACT FROM AUTHOR]

Samples of magnesium aluminum spinel ceramics doped with manganese ions were prepared by a high-temperature solid-state reaction method; their potential as red-emitting phosphors was analyzed using a time-resolved luminescence spectroscopy technique, from room temperature to 10 K. It was found that in the red spectral range, the luminescence spectra of manganese ions in the MgAl2O4 spinel showed a narrow band peaking at 651 nm due to the emission of Mn4+ and a broader emission band in the region of 675 ÷ 720 nm; the ratio of intensities for these bands depends on the synthesis conditions. By applying a special multi-step annealing procedure, the MgAl2O4:Mn4+ phosphor containing only tetravalent manganese ions, Mn4+, was synthesized. Broad-band far-red emission observed from MgAl2O4:Mn and Mg1.25Al1.75O3.75F0.25:Mn phosphors, prepared by a conventional method of a solid-state reaction, was interpreted as coming from Mn3+ ions. [ABSTRACT FROM AUTHOR]