Search

Morphology plays a crucial role in defining the optical, electronic, and mechanical properties of halide perovskite microcrystals. Therefore, developing strategies that offer precise control over crystal morphology during the growth process is highly desirable. This work presents a simple scheme to simultaneously grow distinct geometries of cesium lead bromide (CsPbBr3) microcrystals, including microrods (MR), microplates (MP), and microspheres (MS), in a single chemical vapor deposition (CVD) experiment. By strategically adjusting precursor evaporation temperatures, flux density, and the substrate temperature, we surpass previous techniques by achieving simultaneous yet selective growth of multiple CsPbBr3 geometries at distinct positions on the same substrate. This fine growth control is attributed to the synergistic variation in fluid flow dynamics, precursor substrate distance, and temperature across the substrate, offering regions suitable for the growth of different morphologies. Pertinently, perovskite MR are grown at the top, while MP and MS are observed at the center and bottom regions of the substrate, respectively. Structural analysis reveals high crystallinity and an orthorhombic phase of the as-grown perovskite microcrystals, while persistent photonic lasing manifests their nonlinear optical characteristics, underpinning their potential application for next-generation photonic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Objectives: To investigate whether post‐stroke statin therapy reduces subsequent major vascular events in statin‐naïve patients with pretreatment low‐density lipoprotein cholesterol (LDL‐C) below the recommended target (≤70 mg/dL for atherosclerotic stroke and ≤100 mg/dL for non‐atherosclerotic stroke) at stroke onset. Methods: Patients from an ongoing stroke registry who had an ischemic stroke between 2011 and 2020 were screened. Statin naïve patients with baseline LDL‐C below the target were assessed. The effect of post‐stroke statin therapy on major vascular events (composite of recurrent stroke, myocardial infarction, and death) was investigated using weighted Cox regression analyses using stabilized inverse probability treatment weighting. Results: The baseline LDL‐C level of the 1,858 patients (mean age 67.9 ± 15.3 years, 61.4% men, 13.2% atherosclerotic stroke) included in the study was 75.7 ± 17.0 mg/dL. Statins were prescribed to 1,256 (67.7%) patients (low‐to‐moderate intensity, 23.5%; high intensity, 44.1%). Post‐stroke statin therapy was associated with a lower risk of major vascular events during 1‐year follow‐up (weighted hazard ratio 0.55, 95% confidence interval 0.42–0.71). In a subgroup of patients who were at very high risk of atherosclerotic cardiovascular disease with LDL‐C <55 mg/dL or patients who were not at very high risk of atherosclerotic cardiovascular disease with LDL‐C <70 mg/dL, post‐stroke statin therapy was also associated with a reduction in major vascular events (weighted hazard ratio 0.45, 95% confidence interval 0.29–0.70). The intensity of the most beneficial statin varied by subtype of stroke. Interpretation: Statin therapy may improve vascular outcomes after ischemic stroke, even in cases of LDL‐C below the target without pre‐stroke lipid‐lowering therapy. ANN NEUROL 2024;95:876–885 [ABSTRACT FROM AUTHOR]

This study was conducted to compare and analyze whether Pilates exercise and yoga exercise help improve the performance of female fencers and prevent injury, and the dynamic balance test (LQ-YBT) and functional movement screening (FMS) test score of the elite adult female fencers were compared and analyzed as evaluation indicators. Participants were randomly classified into Pilates (n = 10) and yoga groups (n = 10), members of which took part in 50 min of exercise (5 min of warm-up, 40 min of main exercise, and 5 min of cool-down) twice weekly for eight weeks. The results obtained from this study were analyzed via independent t-test and 2-way ANOVA. The results were as follows: LQ-YBT measures (reaching distance) increased significantly for both groups, as did FMS scores (deep squat, hurdle step, inline lunge, shoulder mobility, active straight-leg raise, trunk-stability push-up, and rotary stability). These results suggest that Pilates exercise and yoga exercise might be likely effective in improving the performance of adult female fencers and injury prevention by increasing their dynamic balance ability and functional movement. [ABSTRACT FROM AUTHOR]

Recently, mixed‐cation halide perovskites have gained significant attention for developing stable, high‐performance solar cells. However, their nonlinear optical (NLO) properties are much less explored. Herein, this study reports on intriguing NLO properties observed from FA0.8MA0.2PbI3 single crystals, having an ideal bandgap of 1.52 eV for photovoltaic performance. Contrary to a simple prediction, the perovskite exhibits higher‐order multiphoton absorption (MPA) over a broad wavelength range from 1300 to 1710 nm as evidenced by wavelength‐ and intensity‐dependent photoluminescence measurements. The corresponding MPA coefficients are very large to dominate lower‐order ordinary MPA across the bandgap. The hexagonal phase present in the perovskite is responsible for the observed higher‐order transition as confirmed by the recovery of ordinary MPA in the absence of the hexagonal phase. Although the perovskite is known to crystallize into the cubic phase at room temperature, these results indicate that minor inclusion of the hexagonal phase (≈4.0% at room temperature) can drastically alter the nature of the multiphoton process by double resonance uniquely offered by the mixed phases. [ABSTRACT FROM AUTHOR]

Recently, mixed‐cation halide perovskites have gained significant attention for developing stable, high‐performance solar cells. However, their nonlinear optical (NLO) properties are much less explored. Herein, this study reports on intriguing NLO properties observed from FA0.8MA0.2PbI3 single crystals, having an ideal bandgap of 1.52 eV for photovoltaic performance. Contrary to a simple prediction, the perovskite exhibits higher‐order multiphoton absorption (MPA) over a broad wavelength range from 1300 to 1710 nm as evidenced by wavelength‐ and intensity‐dependent photoluminescence measurements. The corresponding MPA coefficients are very large to dominate lower‐order ordinary MPA across the bandgap. The hexagonal phase present in the perovskite is responsible for the observed higher‐order transition as confirmed by the recovery of ordinary MPA in the absence of the hexagonal phase. Although the perovskite is known to crystallize into the cubic phase at room temperature, these results indicate that minor inclusion of the hexagonal phase (≈4.0% at room temperature) can drastically alter the nature of the multiphoton process by double resonance uniquely offered by the mixed phases. [ABSTRACT FROM AUTHOR]

The Bi 2 O 2 Se surfaces are well-known to possess 50% Se vacancies, yet they have shown no in-gap states within the indirect bandgap (∼0.8 eV). We have found that the hidden in-gap states arising from the Se vacancies in a 2 × 1 pattern induce a reduced direct bandgap (∼0.5 eV). Such a reduced direct bandgap is responsible for the high electron mobility of Bi 2 O 2 Se. Moreover, the Bi oxide overlayers of the Bi thin films, formed through air exposure and annealing, unexpectedly exhibit a large direct bandgap (∼2.1 eV). The simplified fabrication of Bi oxide overlayers provides promise for improving Bi 2 O 2 Se electronic devices and enhancing photocatalytic activity.