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Retinal photoreceptor apoptosis is associated with impaired serum ionized calcium homeostasis in diabetic retinopathy: An in-vivo analysis
摘要： Purpose: The aim of this work was to study the association of serum ionized calcium with retinal photoreceptor apoptosis on spectral domain optical coherence tomography (SD-OCT) in diabetic retinopathy (DR). Methods: Sixty consecutive cases with Type 2 diabetes mellitus were categorized into three groups: no diabetic retinopathy; non-proliferative DR; proliferative DR. The eye with more severe form of the disease was considered. Twenty healthy controls were also included. Best corrected visual acuity (BCVA) was measured on logMAR scale. Retinal photoreceptor apoptosis was defined as disruption of retinal photoreceptor ellipsoid zone (EZ). Ellipsoid zone disruption was assessed using SD-OCT. Serum levels of total and ionized calcium were measured using standard protocol. Results: EZ disruption was found to be positively associated with serum total calcium and ionized calcium. Also, EZ disruption was found to be positively associated with logMAR BCVA. Conclusion: Increased serum ionized calcium induces retinal photoreceptor apoptosis resulting in increased EZ disruption in DR.
关键词： Ionized calcium,Retinal photoreceptor apoptosis,Diabetic retinopathy,Autophagy,Ellipsoid zone,Spectral-domain optical coherence tomography
更新于2025-09-23 15:23:52
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Characteristics of Ultrathin Ni Films
摘要： Conductive and transparent ultra-thin Nickel films are grown by RF sputtering on fused silica substrates. The characteristics of Ni films (thickness, refractive index, and extinction coefficient) are obtained by fitting multi-angle spectrophotometric and ellipsometric data. Films thickness inferred by X ray reflection (XRR) measurements is in good accordance with ellipsometric results. XPS analysis reveals that Ni metal phase is present in the film surface together with Ni mixed oxide phases, which explains the high electrical stability of such films.
关键词： optical measurements,ultrathin films,transparent conductive films,Ni films
更新于2025-09-23 15:23:52
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Progrès dans les méthodes diagnostiques du déficit en cellules souches limbiques. Apport de la microscopie confocale et de la tomographie en cohérence optique
摘要： The limbus is the anatomical and functional barrier between corneal and conjunctival epithelia. It is characterized by presence of the limbal stem cell niche which allows corneal homeostasis to be maintained. Limbal stem cell deficiency is characterized by a dual process: insufficient regeneration of corneal epithelium, which cannot therefore assure its function of physiological support, associated with corneal invasion by conjunctival proliferation. Diagnosis is currently made via routine clinical examination, corneal impression cytology and in vivo confocal microscopy (IVCM). Slit lamp examination shows abnormal limbal anatomy, thin and irregular epithelium with late fluorescein staining, and superficial vascularization. With its high resolution, IVCM allows identification of limbal and corneal epithelial changes at a cellular level in en face views, parallel to the corneal surface, but with a restricted viewing field of the corneal surface. It shows a poor transition between the corneal and conjunctival epithelia, associated with a loss of the normal corneal epithelial stratification, low basal cell and sub-basal nerve plexus densities, even with sub-epithelial fibrosis. Optical coherence tomography in central cornea and at the limbus, with scans in different orientations, allows a quick, global and non-invasive analysis of normal eyes and those with limbal stem cell deficiency. It shows a thin limbal epithelium, lacking normal thickening, featuring absence of stromal undulations and limbal crypts in cross-sections and sections parallel to the limbus, lack of visible limbal crypts in en face sections, loss of clear transition between the hyporeflective corneal epithelium and the hyperreflective conjunctival epithelium, and hyperreflective sub-epithelial fibrosis.
关键词： Limbal stem cell deficiency,Limbus,Optical coherence tomography,In vivo confocal microscopy
更新于2025-09-23 15:23:52
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Highly efficient and thermally stable of a novel red phosphor Sr3NaSbO6:Mn4+ for indoor plant growth
摘要： Far red-emitting Mn4+-activated oxide phosphor based on the substitution of Mn4+ for Sb5+ in the lattice of Sr3NaSbO6 (SNSO) was prepared via solid state reaction process. The crystal structure of the host was carefully discussed and studied. The resultant phosphors were characterized by X-ray powder diffraction, fluorescence spectra, ultraviolet-visible diffuse reflectance spectra, temperature-dependent emission spectra (298–548 K), luminescence decay curves and electroluminescence spectra. Excitation and emission spectra indicated that the sample had a wide excitation band in UV(250–400 nm) and exhibited the strong emission band centered at 695 nm. The band structure for SNSO was calculated based on the density functional theory, and the bandgap value of SNSO host is ～2.92 eV. In addition, the mechanism of quenching concentration and energy-transfer of SNSO:Mn4+ were explored and analyzed in detail through calculation. The UV–Vis diffusion reflectance spectra demonstrated that samples had strong absorption (200–550 nm) in the ultraviolet(UV) and near-ultraviolet (NUV) region. The thermal stability of SNSO:Mn4+ was excellent (I423K/I273K = 39.84%). The internal quantum efficiency is 56.2%. In brief, the prepared phosphors had potential application in indoor plant growth as a LED lamp.
关键词： Sr3NaSbO6:Mn4+,Far red-emitting LED,Photoluminescence,Optical properties,Plant growth
更新于2025-09-23 15:23:52
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Spectroscopic properties of Eu:Bi4Ge3O12 single crystal grown by the micro-pulling-down method
摘要： Eu3+-doped Bi4Ge3O12 (BGO) single crystal with the size of ?2 × 83 mm3 was successfully grown by the micro-pulling-down method. The absorption cross section, emission cross section and Judd–Ofelt analysis of Eu:Bi4Ge3O12 (Eu:BGO) were reported for the first time. The absorption cross-section is 1.03 × 10?20 cm2 with full-width at half-maximum of 3.1 nm at around 393 nm. The spectroscopic intensity parameter Ωt (t = 2,4,6), radiative transition probabilities, branching ratios and radiative lifetime were obtained, respectively. Furthermore, the stimulated emission cross-section centered at 611 nm was calculated to be 6.32 × 10?21 cm2. The fluorescence lifetime of 5D0 level was obtained to be 1.51 ms. The results indicate that Eu: BGO single crystal could be a potential laser host in the visible range.
关键词： Micro-pulling-down method,Optical properties,Eu:BGO
更新于2025-09-23 15:23:52
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Dynamic Magneto-optical Inversion in Magnetic Fluid using NanoMOKE
摘要： Systematic inversion of optical anisotropy with magnetic field sweep (0-5000Gauss) has been observed at a critical concentration in the monodispersed magnetic fluids using NanoMOKE III. This experimental technique is significantly novel method to investigate the optical anisotropy of magnetic nano-suspensions with the time-varying magnetic field. In this work, we report a detailed experimental investigation on the field dependent magneto-optical behaviour of dilute water dispersed Fe3O4 based magnetic fluid. Magnetic fluid shows tunable magneto-optical properties which primarily depends on parameters such as, particle concentration, composition and carrier medium. We have observed a systematic inversion in optical anisotropy at critical concentration for a Fe3O4 magnetic fluid with strong spatial dependence. The observed tuneable magneto-optical phenomena have been correlated to the net effect of the structuration process, electronic transitions and gravitational force in the presence magnetic field. This phenomenon leads to the development of two particle size distribution, negative optical activity initially and strong spatial dependence respectively. The present results provide a strong correlation with theoretical models presented to expound the dependency of various parameters on magneto-optical inversion behaviour of magnetic fluids.
关键词： ferrofluids,Magnetic fluids,optical anisotropy,magnetic Inversion,NanoMOKE
更新于2025-09-23 15:23:52
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Routing, spectrum and core assignment algorithms for protection of space division multiplexing elastic optical networks
摘要： Protection is a key issue in optical networks, mainly in spacial division multiplexing (SDM) elastic optical networks (EONs) as these handle the increasing amount of heterogeneous Internet traffic. In this paper, we address protection in SDM-EONs including inter-core crosstalk. We introduce three algorithms, designed to provide 100% protection from single failures. Extensive simulation is used to show that the proposed algorithms prevents the formation of network bottlenecks, thus maintaining the protection of the connections.
关键词： Elastic optical network with space division multiplexing,Survivability,Multi-core fiber
更新于2025-09-23 15:23:52
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Crystal structure, optical and electrical properties of metal-halide compound [C7H16N2][ZnCl4]
摘要： A new organic–inorganic hybrid compound [C7H16N2][ZnCl4] was synthesized by hydrothermal method and characterized by single-crystal X-ray diffraction, IR and Raman spectroscopy, optical absorption, differential scanning calorimetry and dielectric measurements. Single crystal diffraction results showed that [C7H16N2][ZnCl4] crystallizes in the monoclinic system, space group P21/c at room temperature. In the molecular arrangement, the tetrachlorozincate anions are connected to organic cations through N-H...Cl hydrogen bonds. The Raman and IR analyses confirm the presence of the organic groups and the anionic entities. UV–Visible absorption spectrum revealed the energy of the optical band gap. DSC measurements indicated that [C7H16N2][ZnCl4] undergoes three sequential phase transitions at 287, 338 and 356 K. The dielectric study proved the ferroelectric properties below the 338K and indicates their classical character for this compound. The analysis of Nyquist plots revealed the contribution of the bulk mechanism and the grain boundaries.
关键词： Phase transitions,Hybrid material,Crystal structure,Optical absorption,Ferroelectric properties,Conduction mechanism
更新于2025-09-23 15:23:52
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Vascular and structural alterations of the choroid evaluated by optical coherence tomography angiography and optical coherence tomography after half-fluence photodynamic therapy in chronic central serous chorioretinopathy
摘要： Purpose To concurrently evaluate the effect of half-fluence photodynamic therapy (hf PDT) on choriocapillaris (CC) perfusion and choroidal structure in chronic central serous chorioretinopathy (CSC). Methods This prospective study included 48 eyes of 41 patients with chronic CSC. Enhanced depth imaging optical coherence tomography and optical coherence tomography angiography (OCTA) images were analyzed. Choroidal area (CA), luminal area (LA), and stromal area (SA) were computed using Image J software. Results One month after hf-PDT, total CA decreased to 1.312 mm2 from 1.490 mm2 (p < 0.001), LA decreased to 0.981 mm2 from 1.097 mm2 (p < 0.001), and SA decreased to 0.331 mm2 from 0.393 mm2 (p < 0.001). In OCTA, the CC flow in the eyes with CSC (17.75 mm2) was statistically significantly lower than the fellow eyes (18.93 mm2) at the baseline visit (p < 0.001). After hf-PDT, the flow in the choriocapillaris statistically significantly increased to 18.81 mm2 at the first month (p = 0.02). Conclusions OCTA proves that after hf-PDT a significant increase in CC perfusion occurred at first month. The decrease of the luminal areas in enhanced depth imaging optical coherence tomography is mainly due to a decrease in large-caliber vessels, which indicates that hf-PDT has an effect on larger choroidal vessels and spares CC flow.
关键词： Chronic central serous chorioretinopathy,Optical coherence tomography angiography,Half-fluence photodynamic therapy,Choriocapillaris perfusion
更新于2025-09-23 15:23:52
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Investigation of Keratinizing Squamous Cell Carcinoma of the Tongue Using Terahertz Reflection Imaging
摘要： We investigated the feasibility of using terahertz (THz) reflection imaging to detect keratinizing squamous cell carcinoma (SCC) of the tongue. Four fresh keratinizing SCC tissues were studied, which had been surgically resected. All of the keratinizing SCCs were well distinguished from normal healthy tissues. We showed that the tumor regions exhibited low THz reflection despite having higher water content than normal regions. The refractive indices and absorption coefficients were low in the tumor tissues despite the relatively high water content. Our results showed that there were dominant factors such as keratin pearls, other than the water content affecting the THz reflection signal.
关键词： Optical diagnostics for medicine,Tissue diagnostics,Terahertz imaging,Medical and biological imaging,Terahertz spectroscopy
更新于2025-09-23 15:23:52