Publications by authors named "Htoon H"

Purpose: To assess the prevalence and risk factors of myopic macular degeneration (MMD) in young and middle-aged individuals with high myopia in Changsha, central China.

Methods: A total of 445 adults with high myopia (worse than or equal to -5.0 D) were examined between 2021 and 2023.

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The reaction of aqueous suspensions of single-wall carbon nanotubes (SWCNTs) with UV-excited sodium hypochlorite has previously been reported to be an efficient route for doping nanotubes with oxygen atoms. We have investigated how this reaction system is affected by pH level, dissolved O content, and radical scavengers and traps. Products were characterized with near-IR fluorescence, Raman, and XPS spectroscopy.

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The optothermal Raman method is useful in determining the in-plane thermal conductivity of two-dimensional (2D) materials that are either suspended or supported on a substrate. We compare this method with the Stokes/anti-Stokes scattering thermometry method, which can play a role in both calibration of Raman peak positions as well as extraction of the local phonon temperature. This work demonstrates that the Stokes/anti-Stokes intensity ratio plays an important role in determining the in-plane thermal conductivity of 2D tin diselenide (SnSe) dry-transferred onto a polished copper (Cu) substrate.

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Purpose: This study aimed to investigate the longitudinal associations between myopic optic disc features and optical coherence tomography (OCT) measurements of peripapillary retinal nerve fibre layer (RNFL) thickness in young myopic children in Singapore.

Methods: A prospective, single-site cohort study was conducted, involving children aged 7-16 years who participated in the PROM-Kids clinical cohort study from 2019 to 2022. Participants underwent annual assessments, including cycloplegic refraction, axial length measurements, fundus photography, and OCT imaging, with ocular magnification correction.

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Aim: To assess the glycaemic status of Asian patients in a tertiary care dental setting and develop a risk model for undiagnosed diabetes mellitus (DM).

Material And Methods: A total of 1074 participants completed a diabetes risk test questionnaire, full-mouth periodontal examination and a point-of-care HbA1c finger-prick blood test. Univariable logistic regression was performed to assess the effect of potential factors to predict DM, with confirmed diabetes as the outcome.

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Composite quasi-particles with emergent functionalities in spintronic and quantum information science can be realized in correlated materials due to entangled charge, spin, orbital, and lattice degrees of freedom. Here we show that by reducing the lateral dimension of correlated antiferromagnet NiPS flakes to tens of nanometers and thickness to less than ten nanometers, we can switch-off the bulk spin-orbit entangled exciton in the near-infrared (1.47 eV) and activate visible-range (1.

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Purpose: To study the effect of corneal white-to-white diameter on Pentacam Scheimpflug cornea tomography and Corvis ST corneal visualization Scheimpflug technology parameters in myopic eyes.

Methods: In this retrospective cross-sectional study, 190 eyes of 190 Chinese myopic patients (spherical equivalent range: -1.25 D to -11.

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Purpose: To describe the long-term outcomes of phacotrabeculectomy from a tertiary glaucoma service in Singapore.

Design: Retrospective case series.

Methods: Seven hundred ninety-six eyes of 698 patients who underwent phacotrabeculectomy surgery at the Singapore National Eye Centre between 2005 and 2007 with a minimum follow-up of three years were included.

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Purpose: To establish the reliability and validity of five performance-based activities of daily living task tests (ADLTT), to correlate structure to function, to evaluate the impact of visual impairment (VI) on age-related macular degeneration (AMD), and to develop new outcome measures.

Methods: A multidisciplinary team developed five ADLTTs: (1) reading test (RT); (2) facial expression (FE) recognition; (3) item search (IS) task; (4) money counting (MC) task; and (5) making a drink (MD), tested with binocular and monocular vision. ADLTTs were tested for known-group (i.

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Purpose: To compare differences in corneal densitometry (CD) and higher order aberrations (HOAs) in eyes that underwent small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for the treatment of myopia and myopic astigmatism at postoperative months 3, 6, and 12, and to evaluate their changes in a separate cohort of eyes after SMILE enhancement.

Methods: In this prospective, randomized, paired-eye clinical trial, consecutive eligible participants were randomized to undergo SMILE or FS-LASIK in either eye. Main outcome measures were CD and HOAs preoperatively and at 3, 6, and 12 months postoperatively.

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Purpose: To assess intra- (repeatability) and inter-observer (reproducibility) variability of laser speckle flowgraphy (LSFG) for retinal blood flow (RBF) measurement in 20 eyes of wild type (C57BL/6J) mice and effect of intravitreal Aflibercept on RBF in optic nerve head (ONH) region of 10 eyes of Ins2 (Akita) diabetic mice.

Methods: 'Mean blur rate (MBR)' was measured for all quadrants of tissue area (MT), vessel (MV) and total area (MA) of ONH region. Changes in MT were analysed at each timepoint.

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One of the central aims of the field of spintronics is the control of individual electron spins to effectively manage the transmission of quantized data. One well-known mechanism for controlling electronic spin transport is the chiral-induced spin-selectivity (CISS) effect in which a helical nanostructure imparts a preferential spin orientation on the electronic transport. One potential application of the CISS effect is as a transduction pathway between electronic spin and circularly polarized light within nonreciprocal photonic devices.

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We demonstrate an important step toward on-chip integration of single-photon sources at room temperature. Excellent photon directionality is achieved with a hybrid metal-dielectric bullseye antenna, while back-excitation is permitted by placement of the emitter in a subwavelength hole positioned at its center. The unique design enables a direct back-excitation and very efficient front coupling of emission either to a low numerical aperture (NA) optics or directly to an optical fiber.

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Interlayer excitons (IXs) formed at the interface of van der Waals materials possess various novel properties. In parallel development, strain engineering has emerged as an effective means for creating 2D quantum emitters. Exploring the intersection of these two exciting areas, we use MoS/WSe heterostructure as a model system and demonstrate how strain, defects, and layering can be utilized to create defect-bound IXs capable of bright, robust, and tunable quantum light emission in the technologically important near-infrared spectral range.

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Purpose: To evaluate factors influencing stabilisation of myopia in the Singapore Cohort of Risk factors for Myopia.

Methods: We evaluated the longitudinal natural history of 424 myopic participants from 1999 to 2022. The outcome was the change in myopia from the adolescence follow-up visit (aged 12-19 years) to the adulthood follow-up visit (aged 26-33 years).

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Quantum light emitters capable of generating single photons with circular polarization and non-classical statistics could enable non-reciprocal single-photon devices and deterministic spin-photon interfaces for quantum networks. To date, the emission of such chiral quantum light relies on the application of intense external magnetic fields, electrical/optical injection of spin-polarized carriers/excitons or coupling with complex photonic metastructures. Here we report the creation of free-space chiral quantum light emitters via the nanoindentation of monolayer WSe/NiPS heterostructures at zero external magnetic field.

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(1) Background: Cell injection therapy is an emerging treatment for bullous keratopathy (BK). Anterior segment optical coherence tomography (AS-OCT) imaging allows the high-resolution assessment of the anterior chamber. Our study aimed to investigate the predictive value of the visibility of cellular aggregates for corneal deturgescence in an animal model of bullous keratopathy.

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Article Synopsis
  • Focused ion beam implantation can precisely place defect centers in wide bandgap semiconductors but has low activation efficiency for creating single photon emitters.
  • A new scalable technique using multiple low-ion-implantation steps and in situ photoluminescence evaluation achieved a 70% yield of single defects in silicon carbide, significantly improving on typical methods.
  • This method shows promise for enhancing quantum information technologies and can be combined with techniques like annealing and cryogenic operations to work with other materials.
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Article Synopsis
  • * The study involves creating bilayer membranes of BaTiO and LaSrMnO using pulsed laser epitaxy, resulting in materials that exhibit both ferroelectricity and ferromagnetism at room temperature.
  • * The findings suggest that freestanding heterostructures can alter magnetic properties without substrate strain, indicating potential for developing flexible multiferroic oxide membranes for electronic uses.
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Single-walled carbon nanotubes (SWCNTs) with covalent surface defects have been explored recently due to their promise for use in single-photon telecommunication emission and in spintronic applications. The all-atom dynamic evolution of electrostatically bound excitons (the primary electronic excitations) in these systems has only been loosely explored from a theoretical perspective due to the size limitations of these large systems (>500 atoms). In this work, we present computational modeling of nonradiative relaxation in a variety of SWCNT chiralities with single-defect functionalizations.

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Article Synopsis
  • - Diamond color centers, especially the negatively charged silicon vacancy (SiV) center, are important in quantum optics due to their narrow emission linewidth and favorable spin properties, making them suitable for various technologies.
  • - Nanodiamond (ND)-based SiV centers can be integrated into advanced structures for applications like biological imaging and sensing, and ion implantation is a key method for creating specific numbers of these color centers.
  • - The study successfully created single SiV centers in nanodiamonds, showing stable single-photon emission at room temperature, which opens new possibilities for advancements in quantum photonics, sensing, and biomedicine.
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Atomically thin transition metal dichalcogenides (TMDs), like MoSwith high carrier mobilities and tunable electron dispersions, are unique active material candidates for next generation opto-electronic devices. Previous studies on ion irradiation show great potential applications when applied to two-dimensional (2D) materials, yet have been limited to micron size exfoliated flakes or smaller. To demonstrate the scalability of this method for industrial applications, we report the application of relatively low power (50 keV)Heion irradiation towards tuning the optoelectronic properties of an epitaxially grown continuous film of MoSat the wafer scale, and demonstrate that precise manipulation of atomistic defects can be achieved in TMD films using ion implanters.

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Background: Optic neuritis (ON) may be the initial manifestation of neuromyelitis optica spectrum disorder (NMOSD). Aquaporin-4 antibody (AQP4 Ab) is used to diagnose NMOSD. This has implications on prognosis and is important for optimal management.

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Purpose: To assess whether aqueous cytokine profiles and pupil size are altered when high capsulotomy energy is used in eyes undergoing femtosecond laser-assisted cataract surgery (FLACS), and if preoperative use of a topical non-steroidal anti-inflammatory drug (NSAID) has an effect on this.

Methods: This prospective study recruited 83 eyes (63 patients) that were allocated to four treatment groups: conventional phacoemulsification (n = 20 eyes); FLACS with 90% capsulotomy energy without NSAID pretreatment (n = 20 eyes); FLACS with 90% capsulotomy energy with NSAID pre-treatment (n = 21 eyes); and FLACS with 150% capsulotomy energy with NSAID pretreatment (n = 22 eyes). Aqueous humor was collected before and after phacoemulsification to assess cytokine profiles.

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