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A 14-year-old girl presenting with visual loss in both eyes was diagnosed to have healed toxoplasma retinochoroiditis in the right eye with active choroidal neovascularization (CNV) secondary to toxoplasmosis in the left. She underwent combination photodynamic therapy (PDT) and intravitreal bevacizumab as primary treatment. PDT was performed as per the ′Treatment of Age-related Macular Degeneration by Photodynamic therapy′ study protocol and was followed by intravitreal bevacizumab after 2 days. CNV regressed at 8 weeks of follow-up and remained stable at 8 months of follow-up. The initial visual acuity improved from 20/120 to 20/30. Combination therapy with PDT and intravitreal bevacizumab appears to be effective in the treatment of CNV secondary to toxoplasma retinochoroiditis.

AIM: The aim of this study is to evaluate the effect of panretinal photocoagulation (PRP) on macular perfusion using optical coherence tomography-angiography (OCT-A) in eyes with proliferative diabetic retinopathy (PDR) by assessing the vessel density (VD) and the size of the foveal avascular zone (FAZ) of the superficial capillary plexus (SCP) and the deep capillary plexus (DCP), before and after PRP. SETTINGS AND DESIGN: Prospective interventional study. SUBJECTS AND METHODS: Twenty-nine eyes of 17 patients with PDR underwent a measurement of best-corrected visual acuity (BCVA) and were imaged using OCT and OCT-A at baseline and 6-months of follow-up. Patients received three sittings of PRP using frequency-doubled neodymium-doped yttrium aluminum garnet laser. STATISTICAL ANALYSIS USED: The OCT-A variables were analyzed using generalized estimating equations. RESULTS: BCVA was unchanged at 6-months follow-up (P = 0.09). FAZ of SCP and DCP (P = 0.28 and 0.89, respectively), VD at foveal SCP (P = 0.08), foveal DCP (P = 0.05), parafoveal SCP (P = 0.13), and parafoveal DCP (P = 0.07) showed no statistically significant difference at 6 months post PRP. CONCLUSIONS: OCT-A parameters were not significantly affected by PRP at 6-months follow-up indicating no alteration in macular perfusion. Further analyses with larger samples and longer duration are warranted to confirm our results. [ABSTRACT FROM AUTHOR]

Nanomaterials are promising alternatives for creating hardware security primitives that are considered more robust and less susceptible to physical attacks compared to standard CMOS-based approaches. Here, nanoscale electronic circuits composed of tunable ratios of molecules and colloidal nanoparticles formed via self-assembly on silicon wafers are investigated for information and hardware security by utilizing device-level physical variations induced during fabrication. Two-terminal electronic transport measurements show variations in current through different parts of the nanoscale network, which are used to define electronic physically unclonable functions. By comparing different current paths, arrays of binary bits are generated that can be used as encryption keys. Evaluation of the keys using Hamming inter-distance values indicates that performance is improved by varying the ratio of molecules to nanoparticles in the network, which demonstrates self-assembly as a potential path toward implementing molecular-scale hardware security primitives. These nanoelectronic networks thus combine facile fabrication with a large variety of possible network building blocks, enabling their utilization for hardware security with additional degrees of freedom that is difficult to achieve using conventional systems. [ABSTRACT FROM AUTHOR]

Planetary ball-milled zinc oxide (ZnO) nanoparticle suspensions (nanoinks) were used to produce thin film chemiresistive gas sensors that operate at room temperature. By varying milling or grinding parameters (speed, time, and solvent) different thin film gas sensors with tunable particle sizes and porosity were fabricated and tested with dry air/oxygen against hydrogen, argon, and methane target species, in addition to relative humidity, under ambient light conditions. Grinding speeds of up to 1000 rpm produced particle sizes and RMS thin film roughness below 100 nm, as measured by atomic force and scanning electron microscopy. Raman spectroscopy, photoluminescence, and X-ray analysis confirmed the purity and structure of the resulting ZnO nanoparticles. Gas sensor response at room temperature was found to peak for nanoinks milled at 400 rpm and for 30 min in ethylene glycol and deionized water, which could be correlated to an increased film porosity and enhanced variation in electron concentration resulting from adsorption/desorption of oxygen ions on the surfaces of ZnO nanoparticles. Sensor response and dynamic behavior was found to improve as the temperature was increased, peaking between 100 and 150 °C. This work demonstrates the use of low-cost PBM nanoinks as the active materials for solution-processed thin film gas/humidity sensors for use in environmental, medical, food packaging, laboratory, and industrial applications. [ABSTRACT FROM AUTHOR]

Electronic transport is investigated through self‐assembled benzenedithiol–gold nanoparticle networks with tunable molecule‐to‐particle ratios (1:5–50:1) deposited between planar electrodes. Two‐terminal current–voltage measurements of the networks display linear behavior at low bias, which is described using a circuit model that accounts for different network morphologies, tunable via molecule‐to‐nanoparticle ratio, and defects. At larger biases, nonlinear negative differential resistance and hysteresis behavior are observed for different molecular concentrations, which can be attributed to a combination of field‐assisted tunneling and charge trapping occurring in the nanoscale networks. The directed self‐assembly of benzenedithiol–metal nanoparticle molecular electronic networks is suggested for molecular integrated circuits in applications such as memory, switching, hardware security, and computing. [ABSTRACT FROM AUTHOR]

Electronic transport properties of nanoscale networks composed of interconnected molecules/gold nanoclusters are examined via first-principles plane wave scattering density functional theory-based simulations. Au-molecular (benzene/alkanedithiol) junctions and networks, connected in linear chains and Y-, H- and ring-shaped networks were studied. Molecular orbital calculations show HOMO (highest-occupied-molecular-orbital)-LUMO (lowest-unoccupied-molecular-orbital) gaps of chains decreased with length, indicating decreased barrier to electron transport. Orbitals near the gap of benzenedithiol networks show good delocalization whereas those of alkanedithiol molecules were more localized the metallic clusters. The transmission spectra of benzenedithiol-based networks showed increase in number/width of peaks near the Fermi energy as structures were extended due to increased orbital overlapping (spatially/energetically) with each other leading to formation of transmission pathways and electronic energy band-like properties. In contrast, lower transmission was observed for networks having localized orbitals (alkanedithiol molecular networks) with less overlap near the Fermi energy. Transmission spectra were also in good agreement with associated peaks in electronic density of states. In the case of multi-terminal networks, the location of delocalized orbitals can also shift from one branch to another, indicating potential ON/OFF switching behavior is possible. Switching elements and molecular-scale circuits (e.g., logic gates or inverters) based on Y- and H-shaped networks are proposed in analogy to electron waveguide devices and our simulations indicated that low-energy switching operation on the order of 10-50 meV may be possible. These nanoscale molecular electronic networks linked via metallic clusters provide an avenue for engineering electronics at the molecular level by using superstructures of different organic molecules and topologies. [ABSTRACT FROM AUTHOR]

Electronic transport through self-assembled networks consisting of colloidal gold particles interconnected with thiolated alkane molecules is studied using a combination of broad area and scanning probe microscope-based measurements. The molecule-gold nanoparticle ratio and/or type of molecules is used to alter electronic transport paths through the network and allow the resistance to be controllably tuned by several orders of magnitude (∼105-1011 ohms for the structures studied). Local probing and imaging of the colloidal gold networks via atomic force microscopy is able to detect the presence of molecular connections and also indicates that the number of molecules is important for achieving good network packing with a minimum ratio of molecules to particles between 1:1 and 5:1 found to be needed in order to form well-connected molecular electronic circuits. Circuit simulations used to model the electrical behavior of the self-assembled nanoscale networks based on different morphologies and dimensions show good agreement with experiment and provide a guide for engineering network properties using superstructures of different molecules. These results demonstrate directed self-assembly as a potential avenue for the creation of molecular integrated circuits. [ABSTRACT FROM AUTHOR]

Optic nerve colobomas are congenital defects in the posterior globe of eye with typical funduscopic appearances. We report a two-year-old child suspected of morning glory disc anomaly who underwent thin-section 3D steady-state magnetic resonance imaging which showed characteristic findings of a tiny defect and discontinuity in the optic nerve head. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate high-risk histopathological features (HRHF) following primary enucleation of eyes with retinoblastoma (RB) and assess the patient outcomes across continents., Methods: Retrospective study of 1426 primarily enucleated RB eyes from five continents., Results: Of all, 923 (65%) were from Asia (AS), 27 (2%) from Australia (AUS), 120 (8%) from Europe (EUR), 162 (11%) from North America (NA), and 194 (14%) from South America (SA). Based on the continent (AS vs. AUS vs. EUR vs. NA vs. SA), the histopathology features included massive choroidal invasion (31% vs. 7% vs. 13% vs. 19% vs. 27%, p=0.001), post-laminar optic nerve invasion (27% vs. 0% vs. 16% vs. 21% vs. 19%, p=0.0006), scleral infiltration (5% vs. 0% vs. 4% vs. 2% vs. 7%, p=0.13), and microscopic extrascleral infiltration (4% vs. 0% vs. <1% vs. <1% vs. 4%, p=0.68). Adjuvant chemotherapy with/without orbital radiotherapy was given in 761 (53%) patients. Based on Kaplan-Meier estimates in different continents (AS vs. AUS vs. EUR vs. NA vs. SA), the 6-year risk of orbital tumor recurrence was 5% vs. 2% vs. 0% vs. 0% vs. 12% (p<0.001), systemic metastasis was reported in 8% vs. 5% vs. 2% vs. 0% vs. 13% (p=0.001), and death in 10% vs. 3% vs. 2% vs. 0% vs. 11% (p<0.001) patients., Conclusion: There is a wide variation in the infiltrative histopathology features of RB across continents, resulting in variable outcomes. SA and AS had a higher risk of orbital tumor recurrence, systemic metastasis, and death compared to AUS, EUR, and NA., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Opthalmic Communications Society, Inc.)

Self-assembly offers unique possibilities for fabricating nanostructures, with different morphologies and properties, typically from vapour or liquid phase precursors. Molecular units, nanoparticles, biological molecules and other discrete elements can spontaneously organise or form via interactions at the nanoscale. Currently, nanoscale self-assembly finds applications in a wide variety of areas including carbon nanomaterials and semiconductor nanowires, semiconductor heterojunctions and superlattices, the deposition of quantum dots, drug delivery, such as mRNA-based vaccines, and modern integrated circuits and nanoelectronics, to name a few. Recent advancements in drug delivery, silicon nanoelectronics, lasers and nanotechnology in general, owing to nanoscale self-assembly, coupled with its versatility, simplicity and scalability, have highlighted its importance and potential for fabricating more complex nanostructures with advanced functionalities in the future. This review aims to provide readers with concise information about the basic concepts of nanoscale self-assembly, its applications to date, and future outlook. First, an overview of various self-assembly techniques such as vapour deposition, colloidal growth, molecular self-assembly and directed self-assembly/hybrid approaches are discussed. Applications in diverse fields involving specific examples of nanoscale self-assembly then highlight the state of the art and finally, the future outlook for nanoscale self-assembly and potential for more complex nanomaterial assemblies in the future as technological functionality increases., (© 2022 IOP Publishing Ltd.)

Optic nerve colobomas are congenital defects in the posterior globe of eye with typical funduscopic appearances. We report a two-year-old child suspected of morning glory disc anomaly who underwent thin-section 3D steady-state magnetic resonance imaging which showed characteristic findings of a tiny defect and discontinuity in the optic nerve head., (© 2020 Taylor & Francis Group, LLC.)