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Z-scheme (BiO)2CO3|Cu2O photocatalyst for highly selective CO2 to CO conversion
No full textPhotocatalytic conversion presents a promising approach for developing eco-friendly CO2 reduction catalysts; however, achieving high reaction efficiency and product selectivity remains challenging. In this study, an exceptionally efficient photocatalyst for CO2 conversion was developed by constructing a Z-scheme heterojunction through the growth of p-type Cu2O crystals within an n-type (BiO)2CO3 layer. This architecture effectively suppressed charge recombination, markedly enhancing photoconversion efficiency. While single Cu2O semiconductors exhibit selective CO2-to-CO reduction, their catalytic efficiency is low (CO production of 0.24 μmol g-1h-1). In contrast, the Z-scheme system with (BiO)2CO3 significantly improved charge separation and transfer efficiency. This heterojunction demonstrated outstanding catalyst activity in CO2 conversion, achieving 100 % selectivity and producing 9.79 μmol g-1h−1 of CO gas, while also maintaining high stability through repeated cycles of photocatalytic use. © 2024 Elsevier B.V.FALSEsciescopu
Eco-Friendly Synthesis of Aqua-Nanoparticles via e-Beam Induced Self-Assembly and Polymerization
No full textUnderstanding supramolecular nanoparticle formation pathways remains challenging despite their importance in materials science. Although these nanostructures emerge from "encoded" molecular components, the mechanisms governing assembly are poorly understood. We address this gap through a liquid-cell transmission electron microscopy platform that uses electron beam (e-beam) simultaneously as imaging tool and polymerization energy source. This water-based methodology eliminates organic solvents while enabling precise structural control, aligning with green chemistry. Our research utilizes specially designed rod-coil organic molecules that simultaneously self-assemble and polymerize under controlled e-beam irradiation in water. The developed platform enables real-time visualization of dynamic self-assembly kinetics, including diffusion, collision, fusion, and growth processes. This in-situ imaging provides unprecedented insights into the formation mechanisms of hierarchical nanostructures. By precisely tuning molecular parameters and irradiation conditions, we can kinetically control the assembly process to produce uniform nanoparticles with defined dimensions and morphologies. Our findings reveal that e-beam-induced polymerization can either promote or inhibit self-assembly, providing a powerful mechanism for structural control. We have successfully scaled this methodology beyond the microscope environment to develop a practical batch synthesis process that maintains precision and uniformity. This research contributes to
understanding complex self-assembly processes while establishing a sustainable platform for producing uniform organic nanoparticles with applications in optoelectronics, energy harvesting, and biomedical fields. By combining molecular design, controlled polymerization, and advanced imaging techniques, we present a comprehensive strategy for synthesizing next-generation nanomaterials that balance maximal performance with minimal environmental impact
Ultrafast on-demand exciton formation in a single-molecule junction by tailored terahertz pulses
No full textThe ultrafast manipulation of molecular states by charge transfer is essential for characterizing and controlling molecular dynamics. In this study, we demonstrated exciton formation in a single molecule through ultrafast electron tunneling processes between a molecule and a metal tip of a scanning tunneling microscope (STM) using a phase-controlled terahertz (THz) pulse. The pronounced luminescence of the well-defined molecular system under the distinct carrier-envelope phase of the THz pulse revealed that sequential state-selective electron-tunneling processes to the frontier molecular orbitals promoted ultrafast exciton formation in the molecule at the STM junction. Furthermore, ultrafast control of exciton formation was achieved using phase- and delay-controlled THz pulse pairs, providing a route for the regulation of molecular dynamics and the emergence of new molecular functions.FALSEsciescopu
Synergistic effects of conductive hydrogels and electrical stimulation in volumetric muscle loss
No full textFunctional biomaterials capable of providing regenerative environments have been widely studied to facilitate efficient repair of volumetric muscle loss (VML). In this study, we devised an injectable conductive hydrogel composed of MXene (Ti3C2Tx), a conductive nanoparticle, and hexanoyl glycol chitosan (HGC), a thermoresponsive polymer, for VML muscle regeneration. Especially, the MXene-containing HGC hydrogel (HGC-MX) with 3 mg/mL MXene and 3 % HGC exhibited good injectability with the sol–gel transition at physiologically relevant temperature (approximately 30 °C) and conductivity (0.8 mS/cm), which can effectively create electroactive environments. Animal studies using a mouse VML defect model revealed that HGC-MX injection significantly facilitated muscle regeneration, as evidenced by enhanced muscle strength recovery, increased skeletal muscle fiber maturation, and reduced fibrosis. Electrical stimulation with HGC-MX further enhanced muscle fiber maturation and angiogenesis, demonstrating its synergistic effect with the conductive hydrogel for muscle regeneration. Overall, our injectable conductive hydrogels provide favorable environments and permit efficient electrical stimulation for skeletal muscle regeneration after VML injury. Our HGC-MX hydrogels can serve as promising and effective platforms for the regeneration of various electroactive tissues, including muscles and nerves. © 2025 Elsevier B.V.FALSEsciescopu
Inducing Chiroptical Properties in Achiral DPP-Based Conjugated Polymers through Intermolecular Interactions and Co-Crystallization with Chiral Small Molecules
No full textChiral optoelectronic materials capable of interacting with circularly polarized (CP) light have emerged as promising candidates for next-generation technologies. This study presents a facile strategy for the preparation of chiroptical films by blending an achiral conjugated polymer, PDVT-10, containing diketopyrrolopyrrole (DPP) moieties with chiral small molecules, 1,1′-binaphthyl-2,2′-diamine (BN). Chirality induction in conjugated polymer systems is driven comprehensively from intermolecular hydrogen bonding to co-crystallization with aggregation, as revealed by a stepwise approach of optical and X-ray scattering analyses depending on the ratio. By optimizing the blending ratio of PDVT-10 and BN to 7:3, near-infrared (NIR)-circularly polarized light-sensitive phototransistors are successfully fabricated on 850nm, which exhibit distinct CP light discrimination and photodetection performance. These findings provide insights into the mechanism of inducing chirality to achiral conjugated polymers, enhancing chiroptical properties, and providing applications in CP photosensitive optoelectronics. © 2025 Elsevier B.V., All rights reserved.FALSEsciescopu
Clinical Application of Vitamin D in Depression
No full textVitamin D, a neuroactive steroid with widespread receptors in brain tissue, has garnered increasing attention as a potential therapeutic agent for major depressive disorder (MDD). This article reviews the current evidence on the efficacy, mechanisms of action, and clinical implications of vitamin D supplementation in MDD treatment. The antidepressant effects of vitamin D are thought to be mediated through multiple mechanisms, including modulation of the hypothalamic-pituitary-adrenal axis, enhancement of neuroplasticity, and anti-inflammatory effects. Current evidence provides mixed support for the use of vitamin D primarily as an adjunctive therapy to standard antidepressants, with limited data on its efficacy as monotherapy. Dosages ranging from 1,500 to 5,000 IU/day for 8 to 20 weeks have shown mixed efficacy in improving depressive symptoms. While generally well tolerated, monitoring is advisable to prevent potential toxicity with long-term use of high doses. The efficacy of vitamin D supplementation may be limited in certain populations such as older adults, while evidence remains inconclusive for perinatal depression. Given its favorable safety profile and potential benefits, vitamin D supplementation warrants consideration as part of a comprehensive treatment approach for MDD, particularly in patients with concurrent vitamin D deficiency. Further research is needed to establish optimal dosing regimens, treatment duration and to explore its efficacy as monotherapy. This review synthesizes the current understanding of the role of vitamin D in MDD treatment and highlights areas for future investigation. © SLACK Incorporated.FALSEssciscopu
Dehydrogenation of a single acetylene molecule on the Cu(111) surface
No full textDehydrogenation of acetylene molecules on metal surfaces is a crucial step in converting acetylene into carbon materials and other useful hydrocarbons for industrial applications. In this study, the dehydrogenation of a single acetylene molecule on a Cu(111) surface was investigated using scanning tunneling microscopy (STM) experiments and density functional theory (DFT) calculations. The dehydrogenation reaction, induced by applying a bias voltage pulse, transforms acetylene to C2 without producing a detectable C2H intermediate, in contrast to similar experiments on Cu(100) where a C2H intermediate was detected. DFT calculations indicate that differences in molecule-surface interactions alter the reaction barrier for the two steps of dehydrogenation. The immediate reaction from acetylene to C2 is driven by a lower reaction barrier for the second C-H bond dissociation compared to the first, along with the absence of an orientation change in the target molecule.FALSEsciescopu
Massive Grant-Free Access With Low Latency Using User Grouping
No full textIn future 6G networks, massive machine-type communications (mMTC) must support highly reliable and low latency uplink transmission. To address these challenges, we propose a user grouping-based data transmission scheme for grant-free mMTC scenarios. Conventional grant-free access schemes typically assume that all active devices transmit data over all available time slots, leading to high inter-user interference and significant detection complexity. In contrast, the proposed scheme divides devices into multiple groups and allocates group-specific data transmission time slots, significantly reducing the number of simultaneous transmissions per slot. This enables faster and more reliable data detection at the base station (BS) using MMSE-based algorithms, while also reducing latency by limiting per-slot detection complexity. The BS further utilizes group membership information to enhance detection performance. Simulation results show that the proposed method outperforms benchmark schemes in terms of symbol error rate (SER), particularly under diverse pilot lengths, BS antenna sizes, and device distributions. The scheme is effective in both homogeneous and heterogeneous device environments, and its low-latency, high-reliability design makes it highly suitable for massive grant-free access in 6G-enabled mMTC systems.MasterCHAPTER I. Introduction 1
CHAPTER Ⅱ. System Model 4
CHAPTER Ⅲ. Massive Grant-free Access Using User Grouping 7
CHAPTER Ⅳ. Simulation Results 11
CHAPTER Ⅴ. Conclusion 21
References 22
Summary (In Korean) 2
Molecularly Engineered Self-Healing Polyimide with Dynamic Bond Exchange for Durable and Flexible Electronics
No full textPolyimide (PI) is a high-performance material with excellent thermal stability, mechanical strength, and chemical resistance, which makes it valuable for aerospace and electronics. However, prolonged cyclic mechanical stress can cause irreversible damage, reducing structural integrity and device lifespan. To overcome this challenge, an intrinsically self-healing PI is developed that enables rapid and efficient damage recovery for advanced electronics. By incorporating disulfide bonds and siloxane-containing aliphatic chains, we enhanced self-healing efficiency through dynamic exchange reactions and improved molecular mobility. The precise molecular design using two tailored diamines resulted in a glass transition temperature (Tg) of 155°C, tensile strength of 66.3 ± 3.4 MPa, toughness of 4.4 ± 1.4 MJ m−3, and 92% self-healing efficiency. This PI maintained mechanical integrity even after multiple healing cycles, ensuring long-term durability. With enhanced toughness and flexibility, this PI is a strong candidate for flexible electronics substrates. Additionally, Joule heating enables on-demand self-healing, providing a fast and energy-efficient repair strategy. This study highlights the superior self-healing, mechanical strength, and long-term durability of molecularly engineered PI, paving the way for next-generation flexible and wearable electronic materials. © 2025 Elsevier B.V., All rights reserved.FALSEsciescopu
