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Non-noble metal catalyst embedded WO3 microspheres for enhancement of NO2 gas sensing
No full textNitrogen dioxide (NO2) is a toxic gas that critically affects air pollution and human health. Although semiconductor-based gas sensors are highly promising for detecting toxic gases, their performance is often limited by low sensitivity and slow recovery times. Noble metal catalysts have been widely employed to overcome these limitations by promoting oxygen spill-over from NO2 to the semiconductor surface, thereby enhancing sensor response. In this work, we fabricated a high-performance NO2 gas sensor using sulfur, which is non-noble metal catalyst, supported on WO3 microspheres via a two-step hydrothermal synthesis. The incorporation of sulfur did not alter the crystallinity or morphology of the WO3, but it introduced additional oxygen vacancies and facilitated the spill-over effect, resulting in a sensing response more than 100 times higher than that of bare WO3. At an operating temperature of 150 degrees C, the sulfur-loaded WO3 exhibited a response of nearly 500-5 ppm of NO2, with a detection limit as low as 50 ppb. This study suggests a viable approach to replacing noble metal catalysts and presents a simple fabrication strategy for developing highly sensitive gas sensors.FALSEsci
Twin structure and phase transition of VO2 film grown on r-plane Al2O3
No full textWe report the twin structure and phase transition of the VO2 thin film grown on an r-Al2O3(0112) substrate. We found that the film is composed of nano-scale grains with their (211) or (200) crystallographic plane-normal close to the substrate-normal direction. The (211) grains exhibited a twin-domain structure separated by the (100) M twin plane, and their (211) plane-normal was tilted away from the substrate normal by 1.45 degrees to accommodate the twin formation. In situ 3D RSMs revealed a gradual reduction of the tilt angle from 1.45 degrees to 1.25 degrees during the monoclinic-to-rutile structural phase transition. In the rutile phase, the tilt angle remained to be finite, indicating that the (100) M twin plane is preserved even in the rutile phase. A comparison with electrical resistance measurements showed that the structural phase transition (SPT) occurs at a temperature lower than the metal-insulator transition (MIT), while the recovery of the tilt angle upon cooling proceeds gradually contrasting the steep resistance change. These results suggest that the twin structure may influence the kinetics of the structural phase transition in VO2 films grown on r-plane sapphire substrates.FALSEsciescopuskc
Exploration of active copper species in copper containing MWW-type zeolitic catalysts for CO oxidation
No full textA series of copper-containing MWW-type zeolitic catalysts (Cu-DML-x) were synthesized at various hydrothermal temperatures (x = 80-200 degrees C), and the catalytic activity in CO oxidation was investigated depending on the copper species. The chemical states of copper on Cu-DML-x catalysts were identified as a framework and extraframework Cu in MWW structure and copper oxides on the external surface depending on the temperature, and these Cu species coexisted with one another. While the MWW structural property was lost with increasing the synthesis temperature, the copper oxide species were additionally formed at higher temperatures. Cu-DML-100 and-120, mainly containing extraframework Cu, demonstrated superior CO oxidation activity compared to Cu-DML-80 with dominant framework Cu. Cu-DML-160,-180, and-200 catalysts, in which extraframework Cu and copper oxides were dominantly present as dual sites, showed the lowest activation energies. This indicates the critical role of extraframework Cu and copper oxides in promoting CO oxidation over zeolites.FALSEsciescopu
The Gwangju Alzheimer's & Related Dementias (GARD) cohort: Over a decade of Asia's largest longitudinal multimodal study
No full textINTRODUCTION Alzheimer's disease (AD) is a major public health concern in Korea, with a high prevalence among older adults. A community-based longitudinal study is essential for tracking disease progression, identifying biomarkers, and developing targeted prevention and treatment strategies. The Gwangju Alzheimer's & Related Dementias (GARD) cohort was established to address these needs through a multimodal approach. METHODS Participants aged >= 60 years undergo comprehensive clinical evaluations, neuroimaging, and biospecimen collection for multi-omics analyses (genomics, transcriptomics, proteomics, and metagenomics) at baseline and systematic follow-up visits. RESULTS From over 17,000 screened individuals, 12,877 were enrolled. Baseline diagnoses include 5,123 cognitively unimpaired (CU), 3,250 mild cognitive impairment (MCI), and 2,125 AD dementia. The resource includes magnetic resonance imaging scans (n = 10,843) and extensive multi-omics data: genomic (n = 10,775), proteomic (n = 116), and microbiome (n = 595). DISCUSSION The integrated GARD dataset provides a powerful and scalable resource for identifying novel biomarkers, understanding disease heterogeneity, and advancing precision medicine for AD.TRUEsci
Revisiting Ferroelectric-Gated Phototransistors: A Tripartite Synapse-Inspired Approach to In-Sensor Image Processing
No full textNeuromorphic devices inspired by the tripartite synapse system offer enhanced modulation of synaptic weight via a third terminal. However, using an electrically independent terminal for memorizing and processing optical information remains unexplored. Here, a ferroelectric-gated phototransistor (FGPT) incorporating ferroelectric polymers and organic photoactive channels is revisited for neuromorphic vision systems. It is demonstrated that partial polarization switching in the ferroelectric gate insulator enables linear control of the photoactive channel. Furthermore, the photogating effect induced by charge trapping at the ferroelectric insulator/photoactive channel interface further enhances the photonic non-volatile (PNV) characteristics of the FGPT. This allows memorized visual information, expressed as photoconductance, to be incrementally potentiated or depressed. The modulated photoconductance fully spans the current level within the dynamic range of the device (153 dB). Finally, the feasibility of the device for all-day face recognition is shown by in-sensor processing of visual information obtained from unstructured environments into the pre-trained range. This approach results in up to a ≈40% improvement in recognition accuracy. © 2025 The Author(s). Advanced Materials published by Wiley-VCH GmbH.TRUEsciescopu
Cell-Laden Constructs with Anisotropic Pores Fabricated by Collagen/Silk-Fibroin for Muscle Tissue Regeneration
No full textAdvancements in bioprinting technology, driven by innovations in bioink formulations, have made it possible to create tissue-engineered constructs that closely replicate the intricate structures of native tissues. Despite the development of numerous cell-laden bioinks, three critical challenges remain: (1) achieving adequate porosity, (2) mimicking the anisotropic morphology of native tissues, and (3) maintaining mechanical properties sufficient for structural integrity. Although previous studies using collagen-based foam bioinks have addressed the issue of porosity, the enhancement of mechanical properties and anisotropic physical structure remains limited. In this study, silk fibroin (S-F) is integrated with collagen to form an interpenetrating polymer network with improved mechanical strength. In addition, a stretching technique is applied to generate anisotropic morphological features, producing biocomposites with enhanced mechanical and structural properties suitable for muscle tissue regeneration. The resulting cell-laden constructs demonstrated significantly improved cellular activities, including myogenic differentiation, which are attributed to their anisotropic oval shapes, aligned collagen fibrils, and mechanical stimulation. These properties are assessed using in vitro and in vivo experiments. The findings suggest that anisotropically porous collagen/S-F constructs offer a versatile platform for anisotropic tissue regeneration, effectively bridging the gap between physical structure and biological function in tissue engineering.FALSEsciescopu
Chemical oxidation and reduction technologies for water and wastewater treatment: Current status, challenges, and future directions
No full textChemical oxidation and reduction technologies have been extensively explored as effective approaches for degrading recalcitrant contaminants in water and wastewater, with several methods already adopted commercially and implemented in real-world applications. This review presents a comprehensive evaluation of the current progress, obstacles, and future prospects of principal redox-based processes, encompassing ozoneand UV-based oxidation, persulfate activation, zero-valent iron reduction, noble metal-catalyzed reduction, electrochemical methods, and photocatalysis. These processes utilize highly reactive oxidizing and reducing agents, which facilitate broad-spectrum contaminant elimination due to robust redox potentials and adaptability to various water matrices. Nevertheless, widespread adoption on a large-scale is still limited by considerable energy consumption, elevated material expenses, and the production of undesirable secondary byproducts. Through systematic analysis of advantages and drawbacks, this review identifies strategies to advance chemical redox technologies toward scalable, energy-efficient, and robust water treatment systems. Ultimately, chemical oxidation and reduction methods demonstrate significant promise for supplementing or exceeding conventional treatment solutions, thus supporting the preservation of clean and safe water resources for generations to come. © 2025 Korean Society of Environmental Engineers.TRUEsciescopuskc
Amorphous boron nitride as an ultrathin copper diffusion barrier for advanced interconnects
No full textThis study focuses on amorphous boron nitride ( alpha-BN) as a novel diffusion barrier for advanced semiconductor technology, particularly addressing the critical challenge of copper diffusion in back-end-of-line (BEOL) interconnects. Owing to its ultralow dielectric constant and robust barrier properties, alpha-BN is examined as an alternative to conventional low-k dielectrics. The investigation primarily employs theoretical modelling, using a Gaussian approximation potential, to simulate and understand the atomic-level interactions. This machine-learning-based potential enables realistic simulations of amorphous alpha-BN structures and allows us to examine how different film morphologies affect barrier performance. Furthermore, we studied the electronic and optical properties of the films using a simple Tight-Binding model. In addition to the theoretical work, we performed copper diffusion experiments through PECVD-grown alpha-BN on Si substrates. Theoretical and experimental results indicate that alpha-BN films can suppress Cu diffusion at nanometre thicknesses. Together, molecular dynamics simulations based on a machine-learned interatomic potential and PECVD experiments support the use of alpha-BN as a Cu diffusion barrier for BEOL interconnects.FALSEsciescopu
Quantitative lipidomics for three-dimensional cell culture using deuterium oxide metabolic labeling
No full textThree-dimensional (3D) cell culture offers a more physiologically relevant model than traditional twodimensional culture, yet standardized methods for lipid quantification in 3D systems are lacking. This study presents a novel quantitative lipidomic approach combining 3D culture with deuterium oxide (D2O) metabolic labeling to provide comprehensive insights into metabolic alterations. Using a hydrogel-based 3D system, we cultured preadipocytes and adipocytes, incorporating macrophage co-culture to induce insulin resistance. Relative lipid quantification was achieved using D2O labeling for global omics relative quantification (DOL-GOReQ). This method enabled the quantification of hundreds of lipids across major categories, including glycerolipids, glycerophospholipids, fatty acyls, and sphingolipids, while also revealing cell-type-specific D-labeling efficiencies. DOLGOReQ analysis revealed that macrophage co-culture significantly reduced long-chain free fatty acids and triacylglycerols (TGs). Quantitative correlation analysis between TGs and free fatty acids indicated that the macrophage-mediated TG reduction stemmed from decreased free fatty acid availability, the precursors for lipid synthesis. Furthermore, macrophages increased D-labeling efficiency, suggesting enhanced lipolysis contributing to TG reduction. DOLGOReQ not only facilitates relative quantification of lipid changes but also provides valuable insights into lipid turnover dynamics. These findings establish DOLGOReQ as a powerful tool for investigating global lipid metabolism changes induced by external stimuli in 3D cell culture.FALSEsciescopu