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Regio- and Stereoselective Cu-Catalyzed Protosilylation of Allenes
No full textAllene, Protosilylation, (Z)-allylsilanes, Cu-catalyst, On-waterAllylsilanes serve as crucial synthetic building blocks in various fields such as organic chemistry and medicinal chemistry due to their high stability and ease of handling. The hydrosilylation of allene using the first-row transition metals to yield allylsilanes is recognized as highly beneficial according to an atom-economy. As many studies have been conducted to achieve the development of high regio- and stereoselective protocols with allenes, we developed the Cu-catalyzed protosilylation of mono- and 1,1-disubstituted allenes to obtain (Z)-allylsilanes. Generally, transition metal-catalyzed hydrosilylations involve the formation of the metal hydride, its insertion to multiple C-C bonds and concomitant σ-bond metathesis to generate C-Si bond. In contrast, we aim to develop a different approach using a PhMe₂Si–Bpin reagent and a proton source, incorporating Si at the terminal carbon and H at the middle carbon in allene moiety. Our protocol showed a broad substrate scope, including mono- and di-substituted allenes and exhibited high yields with excellent regio- and stereoselectivity. We proposed the single-electron pathway based on computational studies and radical trap experiments. Notably, our method can be applicable to on-water reactions, demonstrating its potential applicability in the modification of biomolecules found in daily life, such as glucose, galactose and aspirin analog. Keywords: Allene, Protosilylation, (Z)-Allylsilanes, Cu-catalyst, On-water|본 논문은 유기 규소 화합물의 선택적인 프로토실릴화 반응 개발에 관한 내용이다. 알릴 규소 화합물은 높은 안정성과 다루기 쉬운 장점을 가지고 있어 재료 과학, 유기 합성 등 다양한 분야에서 이용되고 있다. 알릴 규소를 합성하기 위해 코발트나 구리 같은 첫 번째 주기의 전이 금속 촉매를 이용한 알렌의 하이드로실릴화 반응은 경제적인 측면에서 가장 효과적인 방법이다. 다만, 이 반응에 대해서 가장 큰 한계점은 총 여섯 가지의 이성질체가 형성될 수 있으며 이를 위치, 입체 선택적으로 통제하는 것은 매우 어렵다. 특히, 열역학적으로 불안정한 (Z)-알릴규소를 합성하는 방법은 거의 알려진 바가 없다. 이에 우리는 구리 촉매를 이용하여 단일이나 이중 치환된 알렌에 대해서 프로토실릴화 반응으로 (Z)-선택성을 가지는 알릴 규소 합성 방법을 개발하고자 했다. 우리 방법은 구리 촉매와 N,N-리간드 또는 PN 리간드의 복합체 존재 하에 PhMe2SiBpin과 양성자 공급원이 알렌의 말단자리와 중간 탄소에 각 각 삽입된다. 단일 및 이중으로 치환된 알렌의 프로토실릴화 반응은 높은 수율과 선택성을 얻을 수 있었으며, 특히 아민과 산소가 포함된 알렌에 대해서도 목표로 하는 (Z)-알릴규소 화합물을 얻을 수 있었다. DFT 계산과 라디칼 억제제 실험을 기반으로 단일 전자 이동 경로를 통해 (Z)-알릴규소가 형성되는 메커니즘을 제안하였다. 특히, 우리 방법론에서 양성자 공급원과 용매로 물을 사용함으로써, 우리 방법이 유기용매 없이 물에서도 충분히 프로토실릴화 반응이 진행될 수 있음을 강조하였다. 더하여 (Z)-알릴규소를 그램(g) 단위로 합성 가능했으며, 알릴 알코올로 만들기 위한 중간체로 활용됨을 보여주었다. 핵심어: 알렌, 프로토실릴화반응, (Z)-알릴규소, 구리 촉매, 물 반응ABSTRACT i
LIST OF CONTENTS ii
Ⅰ. INTRODUCTION 1
1.1 Backgrounds 1
1.2 Previous studies 1
1.3 Our work 3
II. RESULTS AND DISCUSSIONS 4
2.1 Optimization of reaction conditions 4
2.1.1 Optimization for protosilylation of mono-substituted allene 4
2.1.2 Optimization for protosilylation of 1,1-disubstituted allene 10
2.1.3 Optimization for protosilylation under on-water conditions 11
2.2 Substrate scopes 12
2.2.1 Substrate scopes for protosilylation of mono-substituted allenes 12
2.2.2 Substrate scopes for protosilylation of 1,1-disubstituted allenes 14
2.2.3 Substrate scopes for protosilylation under on-water reaction 16
2.2.4 Chemoselectivity of protosilylation 17
2.3 Mechanistic studies 17
2.4 Synthetic applications 19
III. CONCLUSION 21
IV. EXPERIMENTAL SECTION 22
REFERENCE 65
국문 요약문 69MasterdCollectio
ECoGScope: An integrated platform for real-time Electrophysiology and fluorescence imaging
Get PDFIn this study, we present ECoGScope, a versatile neural interface platform designed to integrate multiple functions for advancing neural network research. ECoGScope combines an electrocorticography (ECoG) electrode array with a commercial microendoscope, enabling simultaneous recording of ECoG signals and fluorescence imaging. The electrode array, constructed from highly flexible and transparent polymers, ensures conformal contact with the brain surface, allowing unobstructed optical monitoring of neural activity alongside electrophysiological recordings. A key innovation is the compact connection module, which securely integrates the ECoG array and microendoscope while minimizing interference with animal behavior. The device was successfully tested in the visual, somatosensory, and frontal cortex, demonstrating its capability for simultaneous electrophysiological and fluorescent measurements. These results highlight the potential of the ECoGScope platform to advance the development of multifunctional tools for studying brain function and addressing neurological disorders. © 2025 The AuthorsTRUEsciescopu
SAM2를 활용한 반지도 3D ABUS 영상 분할을 위한 다중 뷰 학습
No full textAutomated Breast Ultrasound (ABUS), Semi-Supervised Learning, Segment Anything ModelI. INTRODUCTION 1
II. RELATED WORKS 3
1 Semi-supervised medical Image Segmentation 3
2 Segment Anything Models and Adaptation 3
3 Semi-Supervised Medical Image Segmentation With SAM 4
III. Method 5
1 Problem Setting 5
2 Overview of The Proposed Method 5
3 Supervised Adaptation of SAM2 with Detection Token 6
4 Detection Loss 7
5 Semi-Supervised Learning of SAM2 with Multi-Axis Consistency 8
IV. RESULTS 10
1 Experimental Setting 10
2 Results 11
2.1 Comparison with State-of-The-Art Methods 11
2.2 Ablation studies 12
V. CONCLUSION 15
References 16MasterdCollectio
마찰대전 소자 기반의 전기역학 스크린 구조 디자인을 통한 먼지 제거 방향 조절
No full textEnergy harvesting, Triboelectric Nanogenerators, Electrodynamic screen, 3-phase, Unidirectional dust controlⅠ. Introduction 1
1.1 Effects of dust deposition on solar panels 1
1.2 Electrodynamic screen (EDS) technology and its limitation 3
1.3 Triboelectric Nanogenerators 6
1.3.1 Definition and mechanism 6
1.3.2 Operation types of TENGs 9
1.3.3 Rotational triboelectric nanogenerators (RTENGs) 11
1.1.4 RTENG-based EDS 13
1.4 References 16
Ⅱ. Specification optimization of RTENGs for EDS 20
2.1 Introduction 20
2.2 Schematic of RTENG based dust removal by EDS 21
2.2.1 Composition of RTENGs 21
2.2.2 Operation mechanism 24
2.3 Optimization of dust removal 28
2.3.1 Output optimization 28
2.3.2 Dust removal efficiency (DRE) optimization 32
Ⅲ. Comparison between 1-phase and 3-phase EDS 35
3.1 Introduction 35
3.2 Differences of 1-phase and 3-phase RTENG 37
3.2.1 Output performance 37
3.2.2 DRE 38
3.2.3 UV-Vis spectroscopy 43
3.3 Wind-driven RTENGs 44
3.3.1 Rotational speed of RTENGs according to wind speed 44
3.3.2 Recovery test using solar panels 46
Ⅳ. Conclusion 49
Ⅴ. Experimental Section 50
Ⅵ. References 53MasterdCollectio
위성 엣지 컴퓨팅 환경에서의 안전한 코드 오프로딩을 위한 자원관리
No full textLEO Satellite Edge Computing|Secure Code Offloading|Lyapunov Optimization|Physical Layer SecurityThe satellite edge computing (SEC) has recently received considerable attention thanks to its wide area service around the world. However, this also creates a risk of exposing private user data to eavesdroppers. Physical layer security can help prevent this, yet it requires extra usage of network resources. Hence, efficient management of these resources is essential for saving power and ensuring secure code offloading. Moreover, from the perspective of mobile devices that request services, the level of security demands is quite different for various services, yet current studies have not fully considered this aspect. In this paper, we propose a secure code offloading framework for an SEC system with a jam- ming strategy in the existence of eavesdropping satellite. We formulate an average power minimization problem of an LEO satellite, a gateway, and a mobile device while ensuring security and the stability of queues. This includes making decisions of code offloading, computing/network resource allocation, and jamming unit selection. As a solution of this problem, we propose an SOS algorithm by invoking stochastic optimization theory. Fi- nally, via extensive simulations, we demonstrate that the proposed SOS algorithm can save up to 60% of average power compared to existing algorithms while maintaining the same delay and zero leakage of information toward eavesdropper.|위성 엣지 컴퓨팅 (SEC)은 전 세계 넓은 영역에 끊김 없는 서비스를 제공할 수 있는 장점 덕분에 많은 주목을 받고 있다. 그러나 동시에 긴 통신 거리 및 높은 접근성에 의해 사용자 개인 데이터가 도청자에게 노출될 위험을 초래하기도 한다. 물리 계층 보안을 통해 이를 방지할 수 있으나, 추가적인 네트워크 자원 사용이 필요하기 때문에 최소한의 에너지로 안전한 코드 오프로딩을 수행하기 위해 효율적인 자원 관리가 필수적이다. 또한 서비스 요청을 하는 모바일 장치의 관점에서, 다양한 서비스에 대해 요구되는 보안 수준은 매우 다양하지만 기존 연구들은 이를 충분히 고려하지 않고 있다. 본 논문에서는 도청 위성이 존재하는 SEC 시스템에서 재밍을 사용하는 안전한 코드 오프로딩 프레임워크를 제안한다. 우리는 보안 정보의 유출이 없음과 모든 작업이 유한 시간 내에 처리됨을 보장하면서 저궤도 (LEO) 위성, 게이트웨이, 그리고 모바일 장치의 평균 전력을 최소화하는 문제를 정의한다. 이 문제에서는 매 타임 슬롯마다 코드 오프로딩 정책, 컴퓨팅/네트워크 자원 할당, 재밍 유닛 선택 등을 결정한다. 이를 해결하기 위해, 확률적 최적화 이론을 적용한 SOS 알고리즘을 제안한다. 마지막으로, 시뮬레이션을 통해 제안한 SOS 알고리즘이 기존 알고리즘과 비교하여 동일한 지연 시간에 대해 평균 전력을 최대 60%까지 절감할 수 있음을 입증한다.1 Dynamic Secure Code Offloading for Power Minimization in LEO Satellite Edge Computing 1
1.1 Introduction 1
1.2 Related Work 4
1.3 System Model 6
1.4 Problem Formulation and Algorithm 13
1.4.1 Problem Formulation 14
1.4.2 Algorithm Design 14
1.4.3 Dynamic Secure Code Offloading for Energy Minimization in LEO Satellite Edge Computing (SOS) 17
1.5 Simulation Result 19
1.5.1 Simulation Setup 20
1.5.2 Simulation Results 21
1.6 Conclusion 24
References 25MasterdCollectio
Lung Cancer Organoid System to Evaluate the Cytotoxicity of Natural Killer Cells
No full textNatural killer (NK) cells are gaining growing attention due to their promise for immunotherapy. A fast and accurate system is needed to test NK cell biology and their therapeutic application. Here, we report a lung cancer organoid-based system to evaluate NK cells’ cytotoxicity. We first established the lung cancer organoids on top of Matrigel, which allows the co-culture with NK cells. When co-cultured, NK cells moved close to and inside the lung cancer organoids. When we analyzed by flow cytometry, co-culture of NK cells induced a significantly higher ratio of cell death of lung cancer organoids, suggesting that lung cancer organoids can be employed to test the cytotoxicity of NK cells. Finally, the pretreatment of NK cells with A83-01, a TGFβ inhibitor, significantly enhanced the cell death of lung cancer organoids by NK cells, indicating that lung cancer organoid-based system faithfully recapitulates cell line-based system in evaluating the in vitro cytotoxicity of NK cells. These data represent that cancer organoid-based NK cell co-culture system is a reliable platform for studying NK cell biology and evaluating their cytotoxicity for screening for NK cell immunotherapy.TRUEsciescopu
Highly Ordered Micro-Patterned Pore Architecture for Silicon-Based Lithium-Ion Batteries
No full textSiOx/AG composite anode, Perforated current collector, Micro pattern, Pore structure, Mechanical degradation, Rate capabilityⅠ. Introduction
1.1 Overview 1
Ⅱ. Experiment
2.1 Current collector characterization 4
2.2 Electrode fabrication 4
2.3 Cell assembly 4
2.4 Electrochemical measurement 6
2.5 Electrochemical dilatometry 7
2.6 Electrode characterization 8
2.7 Pore structure characterization 8
2.8 Electrochemical modeling and simulation 9
Ⅲ. Results and discussion
3.1 Morphological analysis 12
3.2 Interface properties analysis 14
3.3 Pore structure analysis 17
3.4 Half-cell test 18
3.5 Full cell test 19
3.6 Electrochemical modeling and simulation 23
IV. Conclusion 27
References 29
Summary (in Korean) 32MasterdCollectio
In Silico Analysis of Binding Sites for a Novel ssDNA Aptamer Specific to Verrucarin A and Detection in Dust Extracts
No full textAn aptamer is a single-stranded oligonucleotide that serves as a chemical antibody with a high specificity and binding affinity that can recognize a wide range of molecules. Effective modification and truncation of aptamers can enhance their binding affinities to particular targets while also broadening their application for uses, such as biosensors. However, a conventional trial-and-error methodology hinders this process. Herein, we demonstrate an in silico method to elucidate the binding site of single-stranded DNA aptamer specific to verrucarin A, a mycotoxin produced by molds in indoor buildings that causes adverse effects in living organisms. The novel ssDNA aptamer exhibited a binding affinity of 29.5 nM, demonstrating a relatively strong affinity compared to those of previously reported typical aptamers for small molecules. Furthermore, the selected aptamer was highly specific toward verrucarin A among structurally related mycotoxins (i.e., verrucarol and zearalenone). The specific binding site of the aptamer predicted via molecular dynamics and molecular docking simulations was highly consistent with the results observed via truncation, single base mutation, and circular dichroism experiments. The fluorescence assay revealed limits of detection and quantification of 4.1 and 12 nM for the aptamer, respectively. Comparing our developed aptasensor with LC-MS/MS methodology revealed that it could detect verrucarin A levels in phosphate-buffered saline and dust extracts with robust precision and consistency. Our findings provide insight for future studies exploring interaction mechanisms with intended targets and practical sensing applications, such as point-of-care detection of verrucarin A. © 2024 American Chemical Society.FALSEsciescopu
Stretchable Substrate Surface-Embedded Inkjet-Printed Strain Sensors for Design Customizable On-Skin Healthcare Electronics
No full textStretchable strain sensors have been proposed for personalized healthcare monitoring or human motion detection in a skin-mountable form factor. For customization and stretchable substrate-compatible low-temperature processing, various printing technologies have been utilized to fabricate strain sensors. Hydrophobic stretchable polymers and low viscosity conductive inks are typically used in printed high resolution strain sensor fabrications. However, directly printed strain sensors on hydrophobic stretchable substrates have shown limited printability in pattern continuity, spatial resolution, stretchability, and linearity. Therefore, there is still a need to develop a simple printing process that can fabricate high-resolution stretchable strain sensors for skin-mountable healthcare electronics. In this work, we developed a simple inkjet printing and substrate transfer process for stretchable strain sensors by optimizing a polymer coating layer for enhancing the printed pattern formation, spatial resolution, and substrate transfer efficiency simultaneously while maintaining the benefits of inkjet printing, such as customizability and large-area applicability. The printed stretchable strain sensors are embedded into a stretchable substrate, improving stretchability up to 45% of strain, which successfully detects various parts of our body, such as wrists, fingers, and arms. Further, the printing process scales down the sensors to 150 μm × 6 mm, and the miniaturization enables distinguishing subtle movements of different fingers. © 2024 American Chemical Society.FALSEsciescopu
Direct Photo-Crosslinking Patterning for High-Performance 0D-2D Hybrid Photodetectors
No full textHigh-performance 0D–2D hybrid photodetectors integrated with a crosslinker for direct pattering of quantum dots on the large-scale synthesized MoS2 layer are reported. In the patterned hybrid structure, QD layers are patterned with a resolution of up to 2 µm, ensuring high precision. Enhanced charge transfer from QDs to 2D materials is confirmed using PL quenching, TR-PL, and UPS analysis. As a result, the QD/2D hybrid photodetectors with crosslinker-assisted direct patterning demonstrated a remarkable photoresponsivity of ≈105 A W−1 and a specific detectivity of over 1011 Jones, attributed to the difference in built-in potential. The crosslinker patterning of QDs opens up potential applications for the photodetectors in highly integrated image sensors and can be further extended to high-resolution display industries, eliminating unnecessary fabrication processes. © 2024 Wiley-VCH GmbH.FALSEsciescopu