GIST Scholar
Not a member yet
30271 research outputs found
Sort by
Highly efficient Cu-BiOCl catalysts for continuous microwave-assisted water treatment
No full textThe accelerated impacts of climate change have led to increased variability in raw water quality, compromising the efficiency of conventional water treatment facilities and challenging regulatory compliance. Microwave (MW) assisted advanced oxidation processes (AOPs) present a promising approach by accelerating reaction rates and improving treatment efficiency, enabling adaptation to variable water quality conditions. Realizing this potential requires catalysts with strong MW absorption and high catalytic activity. In parallel, practical strategies for catalyst separation or immobilization are essential for continuous system integration. In this study, we synthesized a highly active Cu-BiOCl catalyst exhibiting a needle and sheet morphology for application in MWassisted Fenton-like reactions. The Cu-BiOCl exhibited excellent performance across a broad pH range (3-8), with particularly high degradation efficiency at neutral to mildly alkaline conditions (pH 7 and 8). Remarkably, the catalyst maintained structural and chemical integrity over 10 consecutive cycles without intermediate washing, confirming its high stability and reusability. To bridge the gap between laboratory performance and real-world application, a MW-assisted continuous flow system was implemented, in which the Cu-BiOCl catalyst was immobilized onto inert carrier beads. This immobilization strategy enabled stable catalyst placement and eliminated the need for post-reaction separation. The system exhibited a linear increase in degradation efficiency with the number of catalyst-coated beads, confirming its scalability and operational practicality for large-scale treatment. These findings highlight the importance of catalyst immobilization and flow system design in translating MW-assisted AOPs into viable solutions for next-generation water treatment infrastructure.FALSEsciescopu
Scalable preparation of highly homogeneous plasmonic gold nanocubes and their application in strong light–matter coupling
No full textPlasmonic gold nanocubes (AuNCs) are highly promising for nanophotonic and plasmonic applications due to their intense localized surface plasmon resonances (LSPRs). However, achieving scalable production of homogeneous AuNCs with reproducible optical properties remains challenging. Here, we introduce a centrifugal depletion‐induced flocculation (CDF) method that yields AuNCs with exceptional uniformity and high recovery (98–99%) within 20–60 minutes. By carefully optimizing centrifugation parameters and depletion‐agent concentrations, we effectively remove synthetic impurities, resulting in nanoparticles with significantly reduced spectral linewidths and high structural uniformity. Using the AuNCs, we demonstrate strong plasmon–exciton coupling with molecular J-aggregates: the hybrids exhibit clear spectral splitting and anti-crossing behavior characteristic of the strong-coupling regime. Notably, smaller AuNCs show stronger coupling due to their higher quality factors and reduced mode volumes. Moreover, implementing a layer‐by‐layer (LBL) coating strategy of J-aggregates on AuNCs further enhances the coupling strength by approximately 21%, as confirmed by experimental measurements and computational modeling. Our approach offers a versatile, scalable route to producing uniform polaritonic nanostructures, enabling their application in advanced optical and quantum‐photonic technologies. © 2025 SPIE. All rights reserved
Enhancing Li+/Mg2+ Separation in Electrically Driven Systems: The Role of Amine Monomer Interfacial Polymerization on SPEEK Membranes
No full textEffect of adhesion force-induced trogocytic molting on T cell in immune response
No full textTrogocytic molting, a process involving the shedding of microvilli-derived immunological synaptosomes (TIS), plays a critical role in T cell activation and immune synapse formation. This study demonstrates that during immune synapse maturation and the subsequent kinapse phase, T cells release TIS enriched with T cell receptors (TCRs). We identified that adhesion forces, primarily mediated by LFA-1, drive this molting process, facilitating TCR-dependent T cell proliferation. Moreover, trogocytic molting significantly enhances T cell activation by activating the PI3K-AKT-mTOR signaling pathway and boosting cellular metabolic activity. These findings reveal trogocytic molting as a crucial mechanism for efficient immune responses, linking adhesion dynamics to metabolic reprogramming in T cells.MasterABSTRACT i
CONTENTS ii
LIST OF FIGURES iv
1. Introduction 1
2. Materials and methods 4
2.1. Reagents and antibodies 4
2.2. Cells 4
2.3. Animals 5
2.4. T cell activation 5
2.6. Western blot analysis 6
2.7. Confocal microscopy 6
2.8. Electron microscopy 7
2.9. Flow cytometry analysis 8
2.10. Seahorse Mito Stress assay 9
2.11. Statistics 9
3. Results 10
3.1. Actin remodeling and microvilli dynamics drive the formation and release of
immunological synaptosomes during T cell activation 10
3.2. Adhesion forces drive trogocytic molting and surface TCR downregulation to
enable proliferation of T cells 11
3.3. Trogocytic molting enhances PI3K-AKT-mTOR signaling, immune synapse formation,
and metabolic activity in T Cells 13
4. Discussion. 20
5. Abstract in Korean (국문요약) 22
6. References 2
Multimodal Analysis of Brain Connectomics and Time-Lagged Functional Dynamics
No full textThis study investigates the structural and temporal organization of the human brain by integrating multimodal neuroimaging data with computational modeling. First, structural and functional brain changes related to depression remission are examined in patients with Alzheimer’s disease and late-life depression using T1-weighted, diffusion, and resting-state functional MRI. An elastic-net model demonstrates the predictive potential of the identified biomarkers. Second, functional dynamics are investigated using Human Connectome Project data. Structurally constrained BOLD (SC-BOLD) signals are generated with a Graph-Net model, and derived time lag matrices quantify interregional propagation delays, revealing how anatomical connectivity shapes functional timing. By combining clinical neuroimaging analysis with computational modeling, this study provides insights into the spatiotemporal architecture of the human brain.|본 연구는 다중모달 뇌영상과 동적 모델링을 결합하여 인간 뇌의 구조적 및 시간적 구조를 탐구한다. 첫째, T1 가중 영상, 확산 MRI, 휴지상태 기능적 MRI 데이터를 활용하여 알츠하이 머 및 노년기 우울증 환자에서 우울증 회복과 관련된 뇌 구조 및 기능 변화를 분석하며, Elastic-net 모델을 통해 임상 상태를 예측하는 바이오마커로서의 가능성을 확인한다. 둘째, Human Connectome Project 데이터를 사용하여 뇌의 기능적 역동성을 분석 한다. GraphNet 모델을 통해 구조적 제약이 반영된 BOLD 신호를 생성하고, 이로부터 도출된 시간 지연 행렬은 뇌 영역 간 정보 전달 지연을 정량화하며, 구조적 연결성이 기능적 시간 구조에 미치는 영향을 밝혀낸다. 임상 뇌영상 분석과 계산 모델링을 통합함으로써, 본 연구는 뇌 네트워크의 시공간적 구조에 대한 통찰을 제공한다.Master1. Introduction 1
1.1 Alzheimer’s Disease and Late-Life Depression 1
1.2 Time Lag Structure 2
1.3 Research Objectives 3
2. Related Works 5
2.1 Generalized Linear Model 5
2.2 Linear Mixed-Effects Model 6
2.3 Correlation Analysis 6
2.3.1 Pearson Correlation Analysis 6
2.3.2 Cross-correlation Analysis 7
3. Connectomic Biomarkers for AD-LLD 8
3.1 Background 8
3.2 Materials and Methods 9
3.2.1 Participants 9
3.2.2 MRI Image Acquisition and Processing 10
3.2.3 Cross-sectional Between-group Differences 11
3.2.4 Longitudinal Between-group Differences 11
3.2.5 Associations with Clinical Phenotype 12
3.3 Results 13
3.3.1 Demographic Information 13
3.3.2 Cross-sectional Between-group Differences 13
3.3.3 Longitudinal Between-group Differences 15
3.3.4 Clinical Effectiveness of Neuroimaging Biomarkers 18
3.4 Conclusion 19
4. Time Lag Structure of Functional Dynamics 21
4.1 Background 21
4.2 Materials and Methods 22
4.2.1 Participants 23
4.2.2 Data Preprocessing 23
4.2.3 Structurally Constrained BOLD Signal Generation 24
4.2.4 Time Lag Matrix 25
4.2.5 Intrinsic Neural Timescale 26
4.3 Experiments and Results 27
4.3.1 Experimental Setups 27
4.3.2 Optimal λg with sFC 27
4.3.3 Temporal Organization of Brain Dynamics 28
4.4 Effect of Structural Regularization on Temporal Dynamics 30
4.4.1 Change in Propagation Lag 30
4.4.2 Change in Correlation with ITS 31
4.5 Discussion 33
4.6 Conclusion 3
Concurrent increases in winter precipitation and summer wildfire risk in a warming Alaska
No full textAlaska is experiencing simultaneous trends of increased winter wetness and heightened summer fire risk due to global warming, leading to more frequent wildfires and greater unpredictability in fire behavior in recent decades. Large-ensemble simulations show that warming drives distinct seasonal changes: in winter, an intensified ridge over the western U.S. enhances moisture transport to Alaska, increasing precipitation while promoting vegetation growth near the Alaska Range. In summer, rising temperatures intensify the fire weather index signaling greater wildfire potential and increase lightning activity. Although the links among these complex seasonal changes remain difficult to validate, temporal overlap-enhanced vegetation growth followed by more fire-conducive weather, and associated increase in lightning could collectively heighten wildfire risk. The robustness of our large-ensemble simulations provides compelling evidence for these cascading effects. Extreme lightning-driven events, such as the Swan Lake Fire, represent the emerging pattern in Alaska's evolving fire regime. The concurrent rise in winter wetness and summer fire conditions underscore the urgent need for adaptive fire management strategies that address these interconnected climate drivers.TRUEsciescopu
Design and fabrication of a metalens for beam shaping in an end-fire optical phased array
No full textOptical phased array (OPA) devices for beam steering and ranging applications have a characteristics built-in architecture that emanates elliptical beam pattern, mainly due to laterally expanded aperture of their end-fire emitter designs [1]. This leads to poor resolution along the vertical direction (i.e., large vertical divergence) due to optical power dispersion, resulting in a short detection range. Various literature has demonstrated the use of cylindrical lenses to collimate the output beam from OPA devices, enhancing desired functionalities such as output beam properties and detection range [2]. In this work, we try to shape the elliptical beam of 64-channel silica end-fire OPA into a sharp spherical beam by the use of metalens with minimal objective distance for more realistic approach. © 2025 Elsevier B.V., All rights reserved
MoSeq based 3D behavioral profiling uncovers neuropathic behavior changes in diabetic mouse model
No full textDiabetic neuropathy (DN) is a prevalent and debilitating complication of diabetes, significantly impairing quality of life through chronic pain, sensory deficits, and motor dysfunction. Despite its widespread impact, current rodent behavioral assessments using 2D tracking methods primarily quantify basic locomotion, such as distance and speed, but lack resolution to detect subtle, pattern-based motor impairments characteristic of DN. This study employed MoSeq-based 3D behavioral profiling combined with unsupervised machine learning to identify subtle yet significant alterations in nicotinamide (NA)- and streptozotocin (STZ)-induced DN mouse models. Our analysis identified 22 distinct behavioral syllables, with DN mice exhibiting increased stress-associated behaviors such as head weaving, wall jumping, and nasal hesitancy, while displaying decreased locomotor activities including walking and rearing. These alterations were accompanied by heightened mechanical sensitivity indicative of neuropathic pain and a more predictable, less exploratory behavioral transition pattern, suggesting a restricted behavioral repertoire rather than improved motor coordination. Additionally, MoSeq-based profiling enabled detailed analysis of movement organization and temporal transitions, highlighting stereotyped behavioral sequences and notably decreased exploratory behaviors in DN mice. These behavioral patterns indicate that DN-associated pain is more strongly related to impairments in behavioral adaptability and higher-order motor planning than to simple reductions in movement, suggesting underlying dysfunctions in sensorimotor or cognitive control circuits. These findings indicate that MoSeq can be used as a valuable tool for high-resolution behavioral quantification in diabetic neuropathic animal pain model, enabling refined evaluation of neuropathic phenotypes and therapeutic efficacy in preclinical studies.TRUEsciescopu
MNP-based Magnetothermal Therapy Scheme
No full textThis dissertation explores the in vivo therapeutic potential of magnetic nanoparticles (MNPs) by leveraging their ability to generate heat when exposed to alternating magnetic fields (AMF). The research focuses on three key applications: magnetic hyperthermia for cancer treatment, magnetothermal brain stimulation for post- stroke functional recovery, and thermal estimation using magnetic particle imaging (MPI). Together, these studies aim to establish a comprehensive framework for magnetothermal therapy.
In the first topic, the physicochemical characteristics of various MNPs were thoroughly analyzed. These characteristics include core size, hydrodynamic diameter, magnetic behavior, and saturation magnetization. The analysis was conducted to predict thermal performance and determine optimal injection concentrations for in vivo applications. Among the tested nanoparticles, Synomag-D exhibited superior properties, making it the most suitable for in vivo applications.
In the second topic, magnetic fluid hyperthermia was applied to cancer therapy. A simulation-guided dosing strategy was developed based on tumor geometry. Using a pancreatic tumor mouse model, it was found that thermal retention strongly depends on tumor size. A critical tumor volume was identified, above which a volume-normalized injection strategy was effective, while smaller tumors required a minimum injection approach. These results underscore the importance of personalized dosing strategies to ensure effective and consistent hyperthermia.
In the third topic, magnetothermal brain stimulation was explored for stroke therapy. Focused magnetic stimulation was applied to the penumbra region to promote functional recovery, representing the first demonstration of non-invasive motor restoration via magnetothermal methods. Simulation and in vivo validation confirmed localized heating, TRPV1 channel activation, and increased blood–brain barrier (BBB) permeability. This method allowed precise, region-specific stimulation with minimal systemic impact, demonstrating strong potential for neuromodulation and stroke rehabilitation.
In the final topic, MPI was employed to estimate MNP concentration and temperature in deep brain regions, enabling near real-time thermal monitoring. MPI revealed that MNPs remained localized at the stimulation site for up to 72 hours, supporting repeatable and sustained heating. The observed temperature reached 40 ℃, satisfying the thresholds required for both TRPV1 activation and BBB modulation. These findings highlight MPI's utility in guiding the spatiotemporal control of therapeutic heating.
Collectively, this work presents a novel MNP-based theranostic platform that integrates localized heating, functional stimulation, and non-invasive temperature monitoring. The proposed approach offers a promising pathway toward personalized, image-guided, and non-invasive nanotherapies across various clinical applications. ©2025 Kim, HoHyeon ALL RIGHTS RESERVEDDoctorAbstract i
List of Contents iii
List of Tables vi
List of Figures vii
I Introduction 1
1 Background and Aim of Research 2
1.1 Background and aim of research 2
1.2 Outline of the dissertation 4
II Magnetic Nanoparticles 6
2 Characterization of MNPs 7
2.1 Motivation 7
2.2 Physical properties and performance evaluation 8
2.2.1 Particle characterization 8
2.2.2 Magnetic particle spectroscopy 14
2.2.3 Magnetophoresis 16
2.2.4 Magnetic hyperthermia 19
2.3 Conclusion 21
III Magnetic Fluid Hyperthermia 23
3 Critical Tumor Size based Hyperthermia Therapy for Pancreatic Cancer 24
3.1 Motivation 24
3.2 Materials and methods 25
3.2.1 Experimental protocol and timeline 25
3.2.2 Estimation of specific loss of power of the MNPs 26
3.2.3 Bio-heat transfer simulation model for pancreatic cancer 28
3.3 Experimental results and discussion 29
3.3.1 Estimating the injection dose and tumor classification 29
3.3.2 In vivo tumor suppression effect and tumor size dependency 31
3.4 Conclusion 35
IV Magnetothermal Brain Stimulation 37
4 Magnetothermal Brain Stimulation for Post-Stroke Motor Recovery 38
4.1 Motivation 38
4.2 Simulation results 39
4.2.1 Experimental conditions and focused magnetic heating 39
4.2.2 Temperature prediction and MNP accumulation for focused heating 41
4.3 Experimental results and discussion 43
4.3.1 Animal protocol 43
4.3.2 Pilot test for changes in blood-brain barrier permeability induced by magnetothermal stimulation 44
4.3.3 In vivo experiment results and motor function recovery 46
4.4 Conclusion 48
V Magnetic Particle Imaging 50
5 MNP Accumulation, Temperature Estimation and BBB Dynamics 51
5.1 Motivation 51
5.2 Materials and methods 52
5.2.1 Fundamentals and physical principles of magnetic particle imaging 52
5.2.2 Experimental protocol 54
5.3 Experimental results and discussion 56
5.3.1 MNP accumulation and estimation of BBB permeability change using IVIS and MPI 56
5.3.2 Temperature estimation based on MPI signal 59
5.4 Conclusion 61
VI Conclusion 63
6 Summary and Further Studies 64
6.1 Magnetic nanoparticles 64
6.2 Magnetic fluid hyperthermia 64
6.3 Magnetothermal brain stimulation 65
6.4 Magnetic particle imaging 65
6.5 Further research directions 66
Bibliography 67
Acknowledgements 7
Fluorinated Biaryl N-Heterocyclic Carbene Ligand with Noncovalent Interaction for Cu-Catalyzed Diastereoselective Addition Reaction
No full textA new class of biaryl Imidazo[1,5-a]pyridin-3-ylidene (ImPy) ligands featuring a Cu─F interaction and a C5-aryl substituent were developed for the diastereoselective addition reactions of easily accessible 1,3-enyne to ketones. X-ray and noncovalent interaction (NCI) analysis indeed demonstrated the presence of a Cu─F interaction and a Cu-arene interaction in the F–ImPy–Cu catalyst. The F–ImPy–Cu complex is an effective catalyst for the diastereoselective addition of a 1,3-enyne nucleophile to ketones, showing up to 96% yields and up to >10:1 diastereoselectivities. © 2025 Wiley-VCH GmbH.FALSEsciescopu