Additional file 1: of A comparison between topical and retrobulbar anesthesia in 27-gauge vitrectomy for vitreous floaters: a randomized controlled trial

CONSORT checklist. (XLSX 14 kb

Additional file 2: of A comparison between topical and retrobulbar anesthesia in 27-gauge vitrectomy for vitreous floaters: a randomized controlled trial

Raw data used and analysed in this study. (XLSX 12 kb

Low-Temperature Solution Synthesis of Transition Metal Dichalcogenide Alloys with Tunable Optical Properties

Nanostructures of layered transition metal dichalcogenide (TMD) alloys with tunable compositions are promising candidates for a broad scope of applications in electronics, optoelectronics, topological devices, and catalysis. Most TMD alloy nanostructures are synthesized as films on substrates using gas-phase methods at high temperatures. However, lower temperature solution routes present an attractive alternative with the potential for larger-scale, higher-yield syntheses of freestanding, higher surface area materials. Here, we report the direct solution synthesis of colloidal few-layer TMD alloys, Mo_<i>x</i>W_1–<i>x</i>Se₂ and WS_2<i>y</i>Se_{2(1–<i>y</i>)}, exhibiting fully tunable metal and chalcogen compositions that span the MoSe₂–WSe₂ and WS₂–WSe₂ solid solutions, respectively. Chemical guidelines for achieving the targeted compounds are presented, along with comprehensive structural characterizations (X-ray diffraction, electron microscopy, Raman, and UV–visible spectroscopies). High-resolution microscopic imaging confirms the formation of TMD alloys and identifies a random distribution of the alloyed elements. Analysis of the tilt-angle dependency of the intensities associated with atomic-resolution annular dark field imaging line scans reveals the types of point vacancies present in the samples, thus providing atomic-level insights into the structures of colloidal TMD alloy nanostructures that were previously only accessible for substrate-confined films. The A excitonic transition of the TMD alloy nanostructures can be readily adjusted between 1.51 and 1.93 eV through metal and chalcogen alloying, correlating the compositional modulation to the realization of tunable optical properties

Spontaneous Formation of Atomically Thin Stripes in Transition Metal Dichalcogenide Monolayers

Whether an alloy is random or ordered can have profound effects on its properties. The close chemical similarity of W and Mo in the two-dimensional semiconductors MoS₂ and WS₂ has led to the expectation that W_<i>x</i>Mo_1–<i>x</i>S₂ is a random alloy. Here we report that triangular monolayer flakes of W_<i>x</i>Mo_1–<i>x</i>S₂ produced by sulfurization of MoO₃/WO₃ are not only nonrandom, but also <i>anisotropic</i>: W and Mo form atomically thin chains oriented parallel to the edges of the triangle, especially around <i>x</i> ∼ 0.5, as resolved by aberration-corrected transmission electron microscopy. First-principles calculations reveal that the binding energies of striped and random alloys are nearly identical but that phase segregation at the growth edge favors one metal over another depending on the local sulfur availability, independent of the composition deeper inside the monolayer. Thus, atomically thin striping is kinetically driven and controlled by fluctuations that couple the local chemical potentials of metals and chalcogenide. Considering the nearly identical electronic properties but very different atomic masses of Mo and W, the resulting striped alloy is electronically isotropic, but vibrationally anisotropic. Phonon anomalies associated with the stripe ordering are predicted, as is an anisotropic thermal conductivity. More generally, fluctuation-driven striping provides a mechanism to produce in-plane subnanometer superlattices within two-dimensional crystals, with broad implications for controlling the electronic, optical, and structural properties of these systems

Defect Coupling and Sub-Angstrom Structural Distortions in W_1–<i>x</i>Mo_<i>x</i>S₂ Monolayers

Two-dimensional materials offer a remarkably rich materials platform to study the origin of different material behaviors at the atomic level, and doping provides a key means of tailoring such materials’ functional properties. The local atomic structure around such dopants can be critically important in determining the material’s behavior as it could modulate scattering, catalytic activity, electronic and magnetic properties, and so forth. Here, using aberration-corrected scanning transmission electron microscopy (STEM) with sub-Ångstrom resolution in conjunction with density functional theory calculations, we demonstrate a strong coupling between Mo dopants and two types of defects in WS₂ monolayers: sulfur monovacancies and grain boundaries. Although Mo does occupy a transition metal lattice site, it is <i>not</i> an ideal substitutional dopant: ∼80% of the S vacancies identified by STEM colocalize with Mo dopants, an affinity that appears to be enhanced by symmetry breaking of a partially occupied midgap defect state. Although a Mo dopant by itself does not considerably distort the WS₂ lattice, it induces substantial lattice deformation by apparently facilitating the charging of a sulfur monovacancy paired with it, which is consistent with the results of first-principles calculations. This coupling of foreign substitutional dopants with vacancies could potentially be exploited to control the distribution and location of chalcogenide vacancies within transition metal dichalcogenides (TMD), by segregating vacancies into regions of high Mo concentration that are purposely placed away from active regions of TMD-based devices

Additional file 1: of Eye exercises of acupoints: their impact on myopia and visual symptoms in Chinese rural children

Eye exercises of acupoints questionnaire. (DOCX 12 kb

Tunable oxygen defect density and location for enhancement of energy storage

Defect engineering is in the limelight for the fabrication of electrochemical energy storage devices. However, determining the influence of the defect density and location on the electrochemical behavior remains challenging. Herein, self-organized TiO2 nanotube arrays (TNTAs) are synthesized by anodization, and their oxygen defect location and density are tuned by a controllable post-annealing process. TNTAs annealed at 600 °C in N2 exhibit the highest capacity (289.2 mAh g−1 at 0.8 C) for lithium-ion storage, while those annealed at 900 °C in N2 show a specific capacitance of 35.6 mF cm−2 and stability above 96% after 10,000 cycles for supercapacitor. Ex situ electron paramagnetic resonance spectra show that the surface-exposed oxygen defects increase, but the bulk embedded oxygen defects decrease with increasing annealing temperature. Density functional theory simulations reveal that a higher density of bulk oxygen defects corresponds to higher localized electrons states, which upshift the Fermi level and facilitate the lithium intercalation kinetic process. Meanwhile, differential charge density calculation indicates that the increase of surface oxygen defects in the anatase (101) plane leads to higher density excess electrons, which act as negative charge centers to enhance the surface potential for ion adsorption. This oxygen-deficient location and density tunable strategy introduce new opportunities for high-energy and high-power-density energy storage systems

Characteristics of children and their parents included in this study.

<p>SD: standrad deviation</p><p>*Children’s baseline refraction was defined as the cycloplegic spherical equivalent (SE) of the right eye at baseline; parental baseline refraction was defined as the non-cycloplegic SE of the right eye at baseline.</p><p>Characteristics of children and their parents included in this study.</p

The relationship between the children’s cycloplegic spherical equivalent (SE) change and paternal/maternal reproductive age in all children using the multivariate LOESS regression model.

<p>Left, unadjusted; Right, father: adjusted for children's age, baseline cycloplegic SE, paternal non-cycloplegic SE, and near work time; mother: adjusted for children's age, baseline cycloplegic SE, maternal non-cycloplegic SE, and near work time.</p

Photoluminescence Segmentation within Individual Hexagonal Monolayer Tungsten Disulfide Domains Grown by Chemical Vapor Deposition

We show that hexagonal domains of monolayer tungsten disulfide (WS₂) grown by chemical vapor deposition (CVD) with powder precursors can have discrete segmentation in their photoluminescence (PL) emission intensity, forming symmetric patterns with alternating bright and dark regions. Two-dimensional maps of the PL reveal significant reduction within the segments associated with the longest sides of the hexagonal domains. Analysis of the PL spectra shows differences in the exciton to trion ratio, indicating variations in the exciton recombination dynamics. Monolayers of WS₂ hexagonal islands transferred to new substrates still exhibit this PL segmentation, ruling out local strain in the regions as the dominant cause. High-power laser irradiation causes preferential degradation of the bright segments by sulfur removal, indicating the presence of a more defective region that is higher in oxidative reactivity. Atomic force microscopy (AFM) images of topography and amplitude modes show uniform thickness of the WS₂ domains and no signs of segmentation. However, AFM phase maps do show the same segmentation of the domain as the PL maps and indicate that it is caused by some kind of structural difference that we could not clearly identify. These results provide important insights into the spatially varying properties of these CVD-grown transition metal dichalcogenide materials, which may be important for their effective implementation in fast photo sensors and optical switches