Vanadium dioxide (VO2) with its unique sharp resistivity change at the metal-insulator transition (MIT) has been extensively considered for the near-future terahertz/infrared devices and energy ...harvesting systems. Controlling the epitaxial quality and microstructures of vanadium dioxide thin films and understanding the metal-insulator transition behaviors are therefore critical to novel device development. The metal-insulator transition behaviors of the epitaxial vanadium dioxide thin films deposited on Al2O3 (0001) substrates were systematically studied by characterizing the temperature dependency of both Raman spectrum and Fourier transform infrared spectroscopy. Our findings on the correlation between the nucleation dynamics of intermediate monoclinic (M2) phase with microstructures will open a new avenue for the design and integration of advanced heterostructures with controllable multifunctionalities for sensing and imaging system applications.
The ability to control nanoparticle size, concentration, and distribution in epitaxial nanocomposite films has been a formidable challenge in the synthesis of nanostructured composite materials. ...Here, a novel 3D super‐nanocomposite (3D‐sNC) architecture is successfully demonstrated by integrating superlattice and vertically aligned nanocomposite structures. In the 3D‐sNC architecture, the feature size and distribution of the nanocylinders such as the height/lateral dimension and the vertical/lateral spacing of nanocylinders can be precisely controlled. The microstructure parameters such as nanocylinder height and spacing modulated interfacial area control the lattice strain, which further tunes the magnetotransport property. These results demonstrate that 3D‐sNC is a simple and yet effective architecture to achieve controlled functionalities via the precise control of nanocylinder size, spacing, concentration, and distribution. Such a 3D‐sNC structure can be used to design advanced nanostructures with desired physical properties for a variety of material systems.
A 3D super‐nanocomposite is achieved by incorporating vertically aligned nanocomposites into a multilayer/superlattice architecture. The dimension and vertical/lateral spacings of nanocylinders can be precisely controlled. The controlled microstructure provides a unique pathway to design lattice strain as well as desired functional properties.
Vanadium dioxide (VO2) is a strong-correlated metal–oxide with a sharp metal–insulator transition (MIT) for a range of applications. However, synthesizing epitaxial VO2 films with desired properties ...has been a challenge because of the difficulty in controlling the oxygen stoichiometry of VO x , where x can be in the range of 1 < x < 2.5 and V has multiple valence states. Herein, a unique moisture-assisted chemical solution approach has been developed to successfully manipulate the oxygen stoichiometry, to significantly broaden the growth window, and to significantly enhance the MIT performance of VO2 films. The obvious broadening of the growth window of stoichiometric VO2 thin films, from 4 to 36 °C, is ascribed to a self-adjusted process for oxygen partial pressure at different temperatures by introducing moisture. A resistance change as large as 4 orders of magnitude has been achieved in VO2 thin films with a sharp transition width of less than 1 °C. The much enhanced MIT properties can be attributed to the higher and more uniform oxygen stoichiometry. This technique is not only scientifically interesting but also technologically important for fabricating wafer-scaled VO2 films with uniform properties for practical device applications.
The purpose of this study was to investigate the genetic mutation spectrum in Chinese patients with familial exudative vitreoretinopathy-associated rhegmatogenous retinal detachment (FEVR-RRD) and to ...analyze the preliminary genotype-phenotype association.
In this consecutive, cross-sectional study, 54 patients with FEVR-RRD were studied. Comprehensive ophthalmic examinations and targeted next-generation sequencing were performed in all patients. The genotype-phenotype association was also analyzed.
Causative mutations were identified in 38.9% (21/54) of patients (14/54 in LRP5, 4/54 in FDZ4, and 3/54 in TSPAN12). The study identified 22 potentially pathogenic mutations in 21 unrelated FEVR probands, and 14 were novel (10/15 in LRP5, 1/4 in FZD4, and 3/3 in TSPAN12). Furthermore, to explore the genotype-phenotype association, late-phase angiographic posterior and peripheral leakage (LAPPEL) was identified in 100% (4/4) of patients with FZD4 mutations and 100% (3/3) of patients with TSPAN12 mutations but only in 42.9% (6/14) of patients with LRP5 mutations. Extraretinal neovascularization (ERNV) was found in 100% (4/4) of patients with FZD4 mutations and in 66.7% (2/3) of patients with TSPAN12 mutations, but only in 21.4% (3/14) of patients with LRP5 mutations.
The positive rate for pathogenic mutations in the known FEVR-associated genes was 38.9% (21/54). Among the mutations, LRP5 mutation was the predominant, accounting for 66.7% (14/21) of genetic positive patients. Patients with FEVR-RRD due to LRP5 mutations have less retinal vascular leakage or neovasculization than do patients with FEVR-RRD due to TSPAN12/FZD4 mutations. Moreover, 14 novel variants were found, which provided a deeper understanding of this disease.
Reading speed in intermittent exotropia (IXT) children has been minimally examined. This study assessed reading speed in school-age children with IXT and determined clinical characteristics of IXT ...that impacted their reading ability. We compared the reading speed of 63 school-age (10-14 years) children with IXT to 44 age-matched normal counterparts. In addition, the correlation between reading speed and clinical characteristics of IXT were evaluated. The reading speed in children with IXT was 231 ± 51 CPM, while reading speed in normal counterparts was 257 ± 33 CPM. Age, gender were found to be factors associated with reading speed in children with IXT. After adjusting for the age and gender, we found a significant correlation between the LogTNO and reading speed in IXT group based on a generalized linear model (p = 0.014). These data show that reading speed was slower in school-age children with IXT assessed with the International Reading Speed Texts. When age and gender were adjusted, poor stereo function at near was found to be related with a slower reading speed.
Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive syndromic form of albinism, characterized by oculocutaneous albinism (OCA) and other systemic complications. The purpose of this study ...was to investigate patients with HPS-associated gene mutations and describe associated ocular and extraocular phenotypes. Fifty-four probands clinically diagnosed as albinism were enrolled. Ophthalmic examinations and genetic testing were performed in all subjects. The phenotypic and genetic features were evaluated. HPS-associated gene mutation was identified in four of the patients with albinism phenotype. Clinically, photophobia, and nystagmus was detected in all (4/4) patients, and strabismus was found in one (1/4) patient. Fundus examination revealed fundus hypopigmentation and foveal hypoplasia in all (8/8) eyes. Eight novel causative mutations were detected in these four HPS probands. Five (62.5%, 5/8) of the mutations were nonsense, two of the mutations were missense (25%, 2/8), and one of the mutations was frameshift (12.5%, 1/8). All patients in our study carried compound heterozygous variants, and all these pathogenic variants were identified to be novel, with most (62.5%, 5/8) of the mutations being nonsense. Our results improved the understanding of clinical ocular features, and expanded the spectrum of known variants and the genetic background of HPS.
Highly oriented multilayered BaTiO3–(Ba,Ca)TiO3–CaTiO3 thin films were fabricated on Nb-doped (001) SrTiO3 (Nb:STO) substrates by pulsed laser deposition. The configurations of multilayered ...BaTiO3–(Ba,Ca)TiO3–CaTiO3 thin films are designed with the thickness ratio of 1:1:1 and 2:1:1 and total thickness ∼300 nm. Microstructural characterization by X-ray diffraction indicates that the as-deposited thin films are highly c-axis oriented and large in-plane strain is determined in BaTiO3 and CaTiO3 layers. Piezoresponse force microscopy (PFM) studies reveal an intense in-plane polarization component, whereas the out-of-plane shows inferior phase contrast. The optimized combination is found to be the BaTiO3–(Ba0.85Ca0.15)TiO3–CaTiO3 structure with combination ratio 2:1:1, which displays the largest domain switching amplitude under DC electric field, the largest room-temperature dielectric constant ∼646, a small dielectric loss of 0.03, and the largest dielectric tunability of ∼50% at 400 kV/cm. These results suggest that the enhanced dielectric and tunability performance are greatly associated with the large in-plane polarization component and domain switching.
To evaluate the microstructure of the fovea in patients with familial exudative vitreoretinopathy (FEVR) compared to healthy controls using optical coherence tomography angiography (OCTA).
In this ...consecutive, cross-sectional, observational case series, 41 eyes of 41 patients diagnosed as FEVR and 37 eyes in 37 control subjects were studied. OCTA was utilized to automatically measure the foveal avascular zone (FAZ) and the vessel density (VD). Inner retinal thicknesses (IRT) and central retinal thickness (CRT) were measured with the instrument caliper. Targeted next-generation sequencing was performed, and phenotype-genotype association was analyzed.
Small FAZ was found in 31.70% (13/41) FEVR eyes but not in controls. Greater CRT and lower superficial foveal VD were noted in FEVR patients. FAZ is negatively correlated with IRT. Persistence of the inner retinal layer (IRL) in fovea was present in 48.78% (20/41) FEVR eyes but not found in controls. Zero percent (0/10) of patients with the low-density lipoprotein receptor-related protein 5 (LRP5) mutation, 50% (1/2) with the frizzled-4 (FZD4) mutation, and 66.67% (3/4) with the tetraspanin-12 (TSPAN12) mutation had preserved foveal IRL and small FAZ.
Our data indicate FEVR status is associated with a significantly smaller FAZ, decreased vascular density in both the superficial and deep layers of parafoveal area, a thicker fovea, and an abnormally preserved IRL in fovea. In addition, patients with the LRP5 mutation had a milder phenotype than those with the FDZ4 or TSPAN12 mutations. These novel findings could provide insight into the understanding of the pathogenesis of FEVR.
A-site cation-ordered perovskite oxide LaBaCo2O5+δ (LBCO) was synthesized and evaluated as a cathode material of intermediate-temperature solid oxide fuel cells (IT-SOFCs). LBCO was structurally ...stable when calcined at 850 °C in air but transformed into cation-disordered structure at 1050 °C. LBCO showed chemical compatibility with Gd0.1Ce0.9O1.95 (GDC) electrolyte at 850 °C and 1000 °C in air. Conductivity of LBCO firstly increased slightly with higher temperature to a maximum of 470 S cm−1 at ∼250 °C and then decreased gradually with further increase in temperature. Electrochemical impedance spectra of the LBCO/GDC/LBCO symmetric cell were measured, and electrode reaction mechanism for the LBCO cathode was analyzed. The electrode polarization resistance of LBCO was mainly contributed by oxygen ionic transfer across the cathode/electrolyte interface and oxygen atom diffusion-electronic charge transfer process. Low area-specific resistances with values ranging from 0.15 Ω cm2 at 650 °C to 0.0086 Ω cm2 at 800 °C were obtained. These results have demonstrated that the A-site cation-ordered perovskite oxide LBCO is a promising cathode material for IT-SOFCs.
► LBCO showed chemical compatibility with GDC at temperatures up to 1000 °C in air. ► LBCO cathode has ASRs ranging from 0.15 Ω cm2 at 650 °C to 0.0086 Ω cm2 at 800 °C. ► The cation-ordered LBCO is very promising as a cathode material of IT-SOFCs.
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