Daegu Gyeongbuk Institute of Science and Technology
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Energy Harvesting and Storage using Highly Durable Biomass-Based Artificial Muscle Fibers via Shape Memory Effect
No full textThis study presents the development of novel artificial muscle fibers from biomass-derived polylactic acid (PLA) and thermoplastic polyurethane (TPU), demonstrating multifunctional properties, including shape memory, energy harvesting, and storage, and offering a sustainable alternative to traditional actuators. The optimized TPU/PLA 4:6 conjugate fiber demonstrates exceptional shape fixity (99.83 %) and shape recovery (99.36 %), with outstanding cyclic durability, retaining over a 98.3 % recovery ratio after fifty consecutive cycles. The fibers exhibit a specific work output of 5.230 J g–1 and can lift weights over 56,000 times their own, significantly outperforming conventional artificial muscle fibers. Twisting (240 turns m−1) and 2-ply configurations enhance tensile strength by 4.18 times compared to untreated shape memory fibers, highlighting their mechanical robustness. The TPU/PLA fibers also generate significant piezoelectric energy directly during the shape memory effect, emphasizing their dual functionality in actuation and energy harvesting. Energy production is significantly higher in the longitudinal direction than in the perpendicular direction, with an open circuit voltage of 488 mV and a short circuit current of 6.28 μA, demonstrating efficient energy generation during deformation and shape recovery. Additionally, CNT-coated fibers display efficient energy storage with a specific capacitance of 42.18 μF cm–1 and retain 90.8 % of their initial capacitance after 1,000 cycles, confirming their durability in repeated applications. © 2024 Elsevier B.V.FALSEsciescopu
N/S co-doped nanocomposite of graphene oxide and graphene-like organic molecules as all-carbonaceous anode material for high-performance Li-ion batteries
Full text linkIn this study, to enhance the electrochemical performance of graphene-based anodes for Li-ion batteries (LIBs), we synthesized an all-carbonaceous N/S co-doped nanocomposite of graphene oxide (GO) and graphene-like small organic molecules (GOM) using a mild, eco-friendly, one-step hydrothermal method with thiourea (CH4N2S) (denoted as h-N/S-GO/GOM). The thiourea facilitated N/S co-doping and π−π bonding, which improved the interaction between hydrophilic GO and hydrophobic GOM in aqueous solution. Notably, the formation of π−π bonds between GO and GOM created pathways that enhanced electron transfer, thereby promoting efficient Li-ion transport from the electrolyte through the channels during rapid charge–discharge cycles. Additionally, the functional groups resulting from N/S co-doping increased the number of active sites within the nanocomposite. Consequently, the h-N/S-GO/GOM anode demonstrated superior electrochemical performance, achieving an average reversible capacity of 1265 mAh g−1 at 0.1 A g−1 and retaining 83.0 % of its capacity after 200 cycles. Furthermore, the nanocomposite exhibited excellent long-term cycling stability, maintaining a capacity of 688 mAh g−1 even after 1000 cycles at a high current density of 1.0 A g−1. The hierarchical network structure of the all-carbonaceous h-N/S-GO/GOM anode facilitated efficient charge transfer between the electrode and electrolyte through shorter diffusion paths for Li-ion transport and provided additional active sites, contributing to its outstanding electrical performance. The h-N/S-GO/GOM nanocomposite represents a promising alternative to traditional graphite-based anodes, offering a path toward high-performance, eco-friendly LIBs suitable for applications such as electric vehicles and energy storage systems. © 2024 The AuthorsTRUEscopu
Phytochrome-interacting factors PIF4 and PIF5 directly regulate autophagy during leaf senescence in Arabidopsis
No full textDuring leaf senescence, autophagy plays a critical role by removing damaged cellular components and participating in nutrient remobilization to sink organs. However, how AUTOPHAGY (ATG) genes are regulated during natural leaf senescence remains largely unknown. In this study, we attempted to identify upstream transcriptional regulator(s) of ATG genes and their molecular basis during leaf senescence in Arabidopsis through the combined analyses of promoter binding, autophagy flux, and genetic interactions. We found that PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and PIF5 directly bind to the promoters of ATG5, ATG12a, ATG12b, ATG8a, ATG8e, ATG8f, and ATG8g, inducing their transcription. These target ATG genes are down-regulated in pif4, pif5, and pif4pif5 mutants, resulting in decreased autophagic activity and slower degradation of chloroplast proteins and chlorophyll. Conversely, overexpression of ATG8 genes accelerated protein degradation with early leaf senescence. Moreover, our data suggested partial suppression of the pif4pif5 phenotype by ATG8a overexpression. PIF4/PIF5 also influence senescence induced by nutrient starvation, another hallmark of the autophagy pathway. Furthermore, we observed that the PIF4/PIF5-ATG regulatory module may contribute to seed maturation. Our study not only unveils transcriptional regulators of autophagy in natural leaf senescence but also underscores the potential role of PIF4/PIF5 as functional regulators in leaf senescence and nutrient remobilization.FALSEsciescopu
Ni-based electrodes on 3D substrates: Development and performance for asymmetric supercapacitors
No full textTo produce high-performance supercapacitors, an easy hydrothermal method was utilized to fabricate the positive electrode employing transition metal nickel and carbonate, which exhibits good wettability and reacts well with aqueous electrolytes. In addition, electrodes without and with a 3D Ni foam substrate were compared, focusing on their surface area and electrochemical performance. The electrodes were fabricated using carbonate (CO32−) based compounds with high wettability. The Ni2(CO3)(OH)2 electrode without Ni foam substrates demonstrated higher electrochemical values at low current densities, while the Ni2(CO3)(OH)2 electrode with Ni foam substrates exhibited higher capacitance at increased current densities. As the current density increased from 3 A/g to 15 A/g, the capacitance of Ni2(CO3)(OH)2 without Ni foam and with Ni foam electrodes decreased by 58.1 % and 46.5 %, respectively. This indicates that higher electrochemical stability is possessed by electrodes directly deposited on Ni foam substrates. The significance of substrate selection for enhancing electrochemical performance is highlighted, with the Ni2(CO3)(OH)2 electrode deposited on Ni foam substrate showing a high capacitance of 101.5mAh/g at a current density of 3 A/g. Additionally, an asymmetric supercapacitor comprising Ni2(CO3)(OH)2 electrodes with Ni foam and graphene as positive and negative electrode, respectively, demonstrated a remarkable energy density of 22.1 W h kg−1 and power density of 673.1 W kg−1 at a current density of 2 A/g. Impressively, excellent cycling stability was exhibited by this asymmetric supercapacitor, with ∼83.4 % capacitance retention after 5000 cycles. © 2024 Elsevier B.V.FALSEsciescopu
Drugcarrier comprising RGD ligand and MNPs for Preventing or Treating of Pancreas cancer
No full textHigh Resolution Direct Photo-crosslinking Patterning of QDs Using Non-heterocyclic Aromatic Thiol Molecules
No full textQuantum Dot, Nanostructure, Patterning, Thiol-ene click chemistry, Transition Metal Dichalcogenide, Hybrid Photodetector, Quantum Dot Light Emitting DiodesCHAPTER 1. INTRODUCTION 1
1.1. Background 1
1.1.1. Quantum Dot 1
1.1.2. Direct Optical Lithography of Functional Inorganic Nanomaterials (DOLFIN) 3
1.1.3. Hybrid Photodetector 5
1.1.4. Quantum Dot Light Emitting Diodes (QLEDs) 7
CHAPTER 2. EXPERIMENTAL SECTION 9
2.1. Synthesis of CdSe/CdZnS Quantum Dot 9
2.1.1. Materials 9
2.1.2. Synthesis of CdSe Core 9
2.1.3. Synthesis of CdSe/CdZnS Core/Shell 10
2.2. Growth of few-layer MoS2 10
2.2.1. Chemicals and Materials 10
2.2.2. Synthesis of MoS2 10
2.3. Ligand Crosslinking using TBBT (Hybrid Photodetector) 11
2.4. CdSe/CdZnS/MoS2 Hybrid Photodetector Device Fabrication 11
2.5. Ligand Crosslinking using TBBT and BPDT (QLEDs) 12
2.6. QLED Device Fabrication 13
2.6.1. Chemical and Materials 13
2.6.2. QLED Fabrication 14
CHAPTER 3. CHARACTERIZATION 15
3.1. Instrumentation 15
CHAPTER 4. RESULT AND DISCUSSION 17
4.1. Direct Photo-Crosslinking Patterning for High-Performance 0D-2D Hybrid Photodetectors 17
4.1.1. Optical Properties and Chemical Analyses of CdSe/CdZnS-TBBT films 17
4.1.2. Direct Photo-Crosslinking Patterning of CdSe/CdZnS using TBBT 23
4.1.3. Carrier Transfer Mechanism of Hybrid Structure 25
4.1.4. 0D-2D Hybrid Photodetector Performance of CdSe/CdZnS-TBBT/MoS2 29
4.1.5. Summary 34
4.2. Role of Conjugated Structure of Crosslinkers in Direct Photo-Crosslinking Patterning of Colloidal Nanocrystals for QLED Performance Enhancement. 35
4.2.1. The Role of Conjugated Structure of Crosslinkers in the Patterning of NCs 35
4.2.2. Solvent Resistance of Quantum Dot Films and Chemical Bonding Analysis of Thiol-ene Reaction 38
4.2.3. CdZnSe/ZnS/CdZnS Pattern Formation and Optical Properties after Patterning Process 42
4.2.4. QLED Performance with Crosslinked CdZnSe/ZnS/CdZnS 47
4.2.5. Summary 50
CHAPTER 5. CONCLUSION 51
References 53
요 약 문 60MasterdCollectio
Gintonin Binds to Reduced LPA4 Receptor Subtype in Human Cortical Neurons in Alzheimer's Disease Brains
Full text linkGinseng, a traditional herbal medicine with a long history of use, is known to support human health, particularly by influencing brain function. Recent studies have identified gintonin, a lysophosphatidic acid (LPA) receptor ligand derived from ginseng, as a key bioactive. However, the specific LPA receptor subtypes targeted by gintonin in the human brain to exert its anti-Alzheimer’s (AD) effects remain unclear. This study aimed to elucidate the LPA receptor subtype targeted by gintonin in the human cortex. Using a fluorescent gintonin conjugate, we investigated receptor binding in cortical samples from healthy individuals (n = 4) and AD patients (n = 4). Our results demonstrated that fluorescent gintonin selectively binds to human cortical neurons rather than glial cells and that gintonin-binding sites are co-localized with the LPA4 receptor subtype. Furthermore, the expression of LPA4 receptors was significantly reduced in the cortical neurons of AD patients. These results suggest that the LPA4 receptor may serve as a novel histopathological marker for AD and represent a promising therapeutic target for gintonin-based prevention and treatment strategies. © 2025 by the authors.TRUEsciescopu
Controlling the Microenvironment of Catalyst via Electrode Engineering for Electrochemical CO2 Reduction
No full textElectrochemical CO2 reduction reaction, ionomer, C-shell crystallinity, microenvironmentAbstract
List of contents
List of figures
Ⅰ. Introduction
1.1 Electrochemical CO2 Reduction Reaction and Electrode System
1.2 Gas Diffusion Electrode System for Efficient CO2RR
1.3 Adlayer Application for Efficient CO2RR
Ⅱ. Controlling the CO2/H2O Ratio by Ionomer for CO2RR Enhancement
2.1 Introduction
2.1.1 Chemical Structure of the Nafion as Cation Exchange Ionomer
2.1.2 Equivalent Weight of Ionomer Changing the Microenvironment of Catalyst
2.1.3 Strategy for Understanding the CO2RR Enhancement Depending on the Chemical
Structure of Ionomer
2.2 Theoretical Background
2.2.1 Parameters for Comparing the Catalytic Reaction Performance of CO2RR
2.2.2 *CO(2) Coverage affecting the CO2RR performance
2.3 Experimental
2.3.1 Preparation of GDE-based catalyst
2.3.2 Analysis of material properties
2.3.3 CO2RR electrolysis
2.3.4 Mechanism study of ionomer effect
2.4 Results and Discussion
2.4.1 Characteristics of Ionomer Layer
2.4.2 CO2RR Performance Enhanced by Ionomer
2.4.3 Improved *CO Coverage by the Ionomers’ Side Chain
2.4.4 Swelling Fraction Change by the Side Chain of Ionomer
2.4.5 Water Reaction and *OH- Coverage Enhancement by Ionomer
2.5 Conclusion
Ⅲ. CO2 and Ion Permeability Control by C-shell Crystallinity
3.1 Introduction
3.1.1 Proton and Alkali Metal Cation Affecting CO2RR
3.1.2 Material Property of Carbon for Microenvironment Control
3.1.3 Research Motivation and Strategies
3.2 Theoretical Background
3.2.1 Boudouard Reaction and C-shell Formation
3.3 Experimental
3.3.1 Cathode Preparation
3.3.2 CO2RR Performance Test
3.4 Results and Discussion
3.4.1 Material Properties of Cu@C Catalysts
3.4.2 CO2RR Performance Regulated by the C-shell Crystallinity
3.4.3 Microenvironment and CO2RR Performance Change by the Crystallinity of C-shell
3.5 Conclusion
Ⅳ. Reference
4.1 Introduction
4.2 Controlling the CO2/H2O Ratio by Ionomer for CO2RR Enhancement
4.3 CO2 and Ion Permeability Control by C-shell Crystallinity
요약문MasterdCollectio