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AltAuthor: A Context-Aware Alt Text Authoring Tool with Image Classification and LMM-Powered Accessibility Compliance
No full textWeb accessibility remains a persistent challenge, particularly in providing appropriate alternative text (alt text) for images that meet the needs of people with visual impairments. Existing tools often generate generic descriptions without taking into account image types and webpage context, leading to alt text that fails to align with established accessibility guidelines. To overcome these limitations, we present AltAuthor, an authoring tool designed to assist developers in managing alt text on existing websites. AltAuthor consists of three key components: (1) Image Classifier, which identifies visual content and its type, (2) Alt Text Generator, leveraging a Large Multimodal Model to generate compliant descriptions by incorporating identified image type, webpage context, and Section 508 accessibility guidelines, and (3) Interactive Authoring Interface, allowing developers to customize automated suggestions. Through this integrated approach, AltAuthor provides developers with tools to enhance accessibility management.N
Cellular Nanointerface of Vertical Nanostructures: Impact of Size-Modulated Nanopillar Arrays on Neuronal Morphology, Maturation, and Synapse Formation
No full textInvestigating the cellular mechanisms facilitated by highly ordered nanostructures in vitro neuronal networks is crucial for advancing biomedical research. However, the intricate effects of these nanostructures on cellular behavior remain unclear. Herein, we explore how variations in nanopillar (NP) array dimensions, defined by the spacing-to-diameter (S/D) ratio, influence cortical neuronal responses-including cellular morphology, mechanosensing, neuronal maturation, and synapse formation. NP arrays with a low S/D ratio accelerate neurite protrusion and enhance neuronal maturation. These topography-driven changes are attributed to the degree of cell confinement on NPs, which can be visualized using focused ion beam scanning microscopy. Furthermore, the synaptic density in cortical neurons declines as the S/D ratio decreases, with neurons preferring to form synapses along the NPs. By utilizing correlative light and electron microscopy, the spatial organization of these synapses is mapped relative to the NP geometries, revealing specialized synaptic regions with remarkable clarity. This approach to designing high-aspect-ratio nanostructures with various S/D ratios holds broad applications in materials engineering, offering insights into nervous system engineering and neural-interfacing bioelectronics.Y
Design Method for Agricultural Irrigation Pipeline Layout and Extra Pipeline Considering Pipe Failure Probability
No full textAs rice paddies are being converted to upland fields, there is necessary to design agricultural irrigation pipelines for upland crops. The layout ofirrigation pipelines needs to consider spatial data, as they tend to be laid on plot boundaries, roads and rivers. The objective of this study was to designirrigation pipeline layouts for stable water supply considering spatial information. Two reservoir irrigation districts (Geoyeo and Shinheung) withsignificant conversion from rice paddies to upland fields were selected as study sites. The optimal number and location of water storages were designedusing a genetic algorithm. The branched pipeline layouts that minimized water supply failure areas were designed using Dijkstra algorithm and takinginto account pipe break probability. To ensure a stable water supply, the reduction in water supply areas was calculated after adding extra pipelinesconnecting branch lines. The results of branched pipeline layout, the Geoyeo site needed 3.2 km of mainline and 15.4 km of branch line, while theShinheung site needed 5.2 km of mainline and 11.2 km of branch line. The water supply failure areas were 2.96 ha in Geoyeo and 2.33 ha inShinheung. The water supply failure areas could be reduced by up to 9% in Geoyeo and by up to 15% in Shinheung by adding extra pipelines. Thisstudy can be applied to determine the layout of agricultural irrigation pipeline, ensuring a stable water supply for upland cropsN
Laser-patterned 2D transparent amorphous phase
No full textFabricating disordered solids at atomic-scale thickness at the desired area is challenging because of the high energy cost of weakening the covalent bonds. Here, we demonstrate a low-power laser-patterning of a transparent amorphous phase on a two-dimensional transition metal chalcogenide alloy. Laser irradiation induces selective evaporation of elements in the crystalline 2H-Mo0.92W0.08Te2 (c-2H), resulting in the progressive phase transformation from crystalline 2H to amorphous MoWTe (a-MoWTe) phase with an intermediate polycrystalline 1T'-Mo0.92W0.08Te2-x (p-1T'). The a-MoWTe has multi-valent cations of Mo5+, W4+, and W6+, indicating that the local chemical environments of a-MoWTe are different from those of c-2H. The multi-valence states of cations could result in a significant lattice disorder by changing the coordination numbers, leading to the phase transformation from crystalline to amorphous phase. Our laser-patterned 2D amorphous phase enables a practical application for next-generation nanoelectronics and photonics, energy storage/conversion, and sensors.N
Double-sided van der Waals epitaxy of topological insulators across an atomically thin membrane
No full textAtomically thin van der Waals (vdW) films provide a material platform for the epitaxial growth of quantum heterostructures. However, unlike the remote epitaxial growth of three-dimensional bulk crystals, the growth of two-dimensional material heterostructures across atomic layers has been limited due to the weak vdW interaction. Here we report the double-sided epitaxy of vdW layered materials through atomic membranes. We grow vdW topological insulators Sb2Te3 and Bi2Se3 by molecular-beam epitaxy on both surfaces of atomically thin graphene or hexagonal boron nitride, which serve as suspended two-dimensional vdW substrate layers. Both homo- and hetero-double-sided vdW topological insulator tunnel junctions are fabricated, with the atomically thin hexagonal boron nitride acting as a crystal-momentum-conserving tunnelling barrier with abrupt and epitaxial interfaces. By performing field-angle-dependent magneto-tunnelling spectroscopy on these devices, we reveal the energy-momentum-spin resonance of massless Dirac electrons tunnelling between helical Landau levels developed in the topological surface states at the interfaces.N
Current trends and future challenges in AI-based English language assessment research: A synthesis study
No full textRecently, generative artificial intelligence (GAI) systems, such as ChatGPT, is becoming a buzz word in almost every sector of our society. This innovative technology is being widely applied, used, and researched in various contexts of English language education and assessment. The main goals of the current paper are to: (a) investigate the current trends in research and development on AI-based English language assessments by reviewing, and analyzing, recently published research studies in South Korea; and (b) identify a program of research that urgently needs to be conducted to facilitate wide application and effective use of GAI in the field of English language assessment in the South Korean context. Results of analyses show that there were few research studies that attempted to newly develop AI-based, automated English assessment systems or rigorously investigate the reliability and validity of such AI-based assessment systems. Implications of the major findings are also discussed along with some promising avenues of future research.N
Facet-dependent reactive oxygen species generation regulates photocatalytic oxidation of benzylamines
No full textThe regulation of active oxygen species (ROS) is a key step in the photocatalytic oxidation process, while the effect of catalyst surface structure on this process has rarely been explored. Herein, we modulate the catalyst surface structure by exposing different crystal facets and disclosing facet-dependent ROS generation mechanism over NH2-MIL-125(Ti). Under light irradiation, {110} facet exposed titanium clusters and {001} facet exposed ligands enrich photogenerated electrons and holes, respectively, while {111} facet exposed titanium clusters and ligands contain both. Accordingly, the {001}, {110} and {111} facet generate distinct ROS of •OH, O2•− and 1O2 through different pathways, respectively. Taking photocatalytic benzylamines oxidation as the model reaction, the O2•− and 1O2 produced on the {110} and {111} facets favor the oxidation benzylamine, while the •OH produced on the {001} facet exhibits catalytic inertia. The present work discloses a facet-dependent ROS generation mechanism and provides a new horizon to the design of photocatalytic systems.N
Simultaneous Detection of Neural Activity and Temperature in Photothermal Neural Stimulation
No full textPhotothermal neuromodulation is a promising non-electrical neural stimulation technology for treating brain diseases through optically induced cell membrane temperature changes. However, the technology faces limitations in understanding its mechanism and impact on cellular behavior due to the restriction of directly measuring temperature changes at the cell interface from a very close distance during optical stimulation of neural cells, necessitating advancements in high-precision temperature sensing and electrical recording without light interference. This challenge is addressed by developing ultrasensitive cell membrane interface temperature sensors integrated with low-noise electrical recording capabilities. Transparent resistive temperature detectors, composed of a 10 nm thickness of ultrathin Au film fabricated by polyelectrolyte seed layer-induced thermal evaporation, achieved precise measurement and control of temperature changes without significant light interference and self-heating. A transparent electrode composed of the same ultrathin Au layer shows low-noise electrical recordings of neural signals upon photothermal stimulation. Using this multifunctional system, it is demonstrated that an average increase of 2.34 degrees C at neuronal cell surfaces results in over 95% suppression of hippocampal neural spike activities. The approach provides unprecedented insights into the mechanisms of photothermal neuromodulation and its effects on cellular behavior, paving the way for advanced treatments of neurological disordersY
Giant charge trapping in 2D layered oxide nanosheets via intrinsic quantum wells
No full textThe atomically thin nature of two-dimensional (2D) layered materials makes them susceptible to charge trapping by randomly created disorders, adversely affecting carrier dynamics such as charge transport and exciton lifetime. Typically, these disorders lead to poor device performance or require additional space to mitigate performance degradation. In this study, we investigate 2D layered Dion-Jacobson (DJ)-phase oxide perovskite nanosheets, which exhibit charge trapping within their well-defined quantum well (QW) structures, resulting in unique tailoring of electrical conductivity and photoconductivity. These DJ-phase perovskites, composed of tunable atomic constituents, demonstrate resonant tunneling and anomalous charge trapping due to their ultra-clean QWs. Remarkably, the conductivity of insulating HSr2Nb3O10 (HSNO) increased over 10 0 0 times upon applying voltage without additional treatments. We observed persistent photoconductivity in 2D vertical heterostructure devices, attributed to charge trapping in QWs, and demonstrated artificial synaptic behaviours in a single flake with tailored energy consumption. Varying the number of perovskite layers significantly allows the tunability of the energy bandgap. This study also highlights the high tunability of 2D perovskite nanosheets, promising various applications, including magnetic, high-k dielectric, and resistive switching devices. Our findings suggest a new class of ionic layered materials with great potential as novel two-dimensional building blocks for device applications. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.N