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Apparatus for nanoparticle agent area detecting in photon-counting CT and method thereof
No full text본 발명은 포톤카운팅 CT에서의 나노입자 조영제 영역 검출 장치 및 그 방법에 관한 것이다. 본 발명에 따르면, 나노입자 조영제 영역 검출 장치는 복수의 보정용 팬텀에 조사된 광선의 측정값을 이용하여 학습 데이터를 생성하고, 생성된 학습 데이터를 광선의 조영제 영역 통과 유무에 따라 제1 그룹과 제2 그룹으로 분류한 다음, 제1 그룹에 대한 제1 확률값과 제2 그룹에 대한 확률값을 산출하는 전처리부, 나노입자 조영제 영역을 검출하고자 하는 원본 사이노그램을 입력받는 영상 입력부, 획득한 원본 사이노그램에 포함된 복수의 픽셀을 K-최근접 이웃(K-NN,K-Nearest Neighbor)알고리즘에 입력하여 해당되는 픽셀에 대한 제1 사후 확률값 및 제2 사후 확률값을 추정하는 확률 추정부, 제1 사후 확률값을 이용하여 제1 사이노그램을 생성하고, 제2 사후 확률값을 이용하여 제2 사이노그램을 생성한 다음, 상기 생성된 제1 사이노그램 및 제2 사이노그램을 역투영(Back projection)하여 역투영 이미지로 변환시키는 이미지 변환부, 그리고 제1 사이노그램을 변환시켜 생성된 제1 역투영 이미지와 상기 제2 사이노그램을 변환시켜 생성된 제2 역투영 이미지를 상호 비교하여 나노입자 조영제 영역을 검출하는 제어부를 포함한다
단기 기억 동안 후측두엽 내에서 지속적인 활동을 위한 전두엽-후측두엽 활동의 중요성
No full textshort-term memory (단기기억);prefrontal cortex (전두엽);posterior parietal cortex (후측두엽);optogenetics (옵토제네틱스 기법) ;acetylcholine (아세틸콜린)Short-term memory (STM), the transient storage and maintenance of information, is a fundamental cognitive process. While previous studies have underscored the role of long-range synaptic connections within the prefrontal cortex (PFC) and the influence of diverse neuromodulators on sustaining neuronal activity and STM, the impact of reciprocal connectivity with the posterior parietal cortex (PPC) on sustained neuronal activity during working memory remains unclear. In this study, we elucidated the dynamic interplay between the PFC and the PPC, shedding light on the mechanisms underlying sustained neuronal firing during short-term memory. Our findings reveal direct and robust synaptic connections from the PFC to the PPC, wherein high-frequency activity of the PFC elicits membrane depolarization in PPC neurons. Notably, we found that cholinergic activation, in conjunction with frontoparietal synaptic activity, induces sustained neuronal firing within the PPC that persists for several seconds. To explore the functional significance of this phenomenon, we employed pharmacological and optogenetic techniques to inhibit frontoparietal synapses or to block muscarinic acetylcholine receptors (mAChRs). Remarkably, the inhibition of frontoparietal synapses or blockage of mAChRs led to a marked decline in performance on a delayed Y-maze task, a behavioral paradigm reliant on STM. Furthermore, We recorded neuronal activity during the behavior task to verify the difference in firing rate during the task and changes of frequency after blockage of acetylcholine release during delay period. These results suggest that the maintenance of sustained activity in the PPC through frontoparietal circuitry, coupled with mAChR activation, represents a critical factor in short-term memory processes. This investigation enhances our understanding of the intricate mechanisms governing STM by elucidating the reciprocal interactions between the PFC and the PPC. Furthermore, it highlights the importance of mAChR activation in sustaining PPC neuronal firing and its impact on STM performance.|본 논문은 PFC-PPC Connectivity 에서의 단기 기억 (STM)과 아세틸콜린의 중요성을 강조합니다. 단기 기억 (STM)은 저장 및 유지는 근본적인 인지 과정입니다. 이전 연구에서는 전두엽 피질 (PFC) 내의 장거리 시냅스 연결의 역할과 다양한 뉴로모듀레이터가 신경 활동 및 단기 기억 유지에 미치는 영향을 강조해 왔지만 작업 기억 중 지속적인 신경 활동과 관련된 후측두엽 피질 (PPC)과의 상호 연결의 영향은 아직 명확하게 밝혀지지 않았습니다. 본 연구에서는 PFC와 PPC 간의 동적 상호 작용을 명료하게 하고 단기 기억 중 지속적인 신경 활동의 기전을 집중하였습니다. 연구 결과는 PFC에서 PPC로 직접적이고 견고한 시냅스 연결이 있음을 보여주며, PFC의 높은 주파수 (10hz)의 영향이 PPC 뉴런의 막 소극화를 유발한다는 것을 밝혔습니다. 특히, 우리는 cholinergic 활성화가 frontoparietal 시냅스 활동과 결합하여 PPC 내에서 지속적인 뉴런 활동을 유발하고 이 활동이 몇 초 동안 지속된다는 것을 발견했습니다. 이 현상의 기능적 중요성을 탐구하기 위해, 우리는 frontoparietal 시냅스 억제 또는 acetylcholine 수용체 차단을 위한 옵토제네틱 기술을 사용했습니다. 놀랍게도, frontoparietal 시냅스 억제 또는 아세틸콜린의 방출 차단은 단기 기억에 의존하는 행동실험에서의 성능 저하를 유발했습니다. 더 나아가, 우리는 행동 작업 중 뉴런 활동을 기록하여 행동 작업 중 Frequency 차이와 지연 기간 중 acetylcholine 방출 차단 이후의 frequency 변화를 검증했습니다. 이러한 결과는 frontoparietal 회로를 통해 PPC에서의 지속적인 활동 유지와 mAChR 활성화가 단기 기억 프로세스에 중요한 요인임을 시사합니다. 이 연구는 PFC와 PPC 간의 상호 작용을 연구하여, STM을 조절하는 복잡한 메커니즘을 이해하는 데 기여합니다. 또한 PPC 뉴런 화재 유지와 STM 성능에 미치는 아세틸콜린 활성화의 중요성을 강조합니다.I. INTRODUCTION
1.1 Sensory information is maintained in the specific regions over delay period 1
1.2 Importance of acetylcholine in short-term memory 6
1.3 PPC dependency to PFC and its role in short-term memory 7
II. MATERIALS AND METHOD
2.1 Animals 11
2.2 Viral vectors 11
2.3 Stereotaxic surgery 11
2.4 in vivo electrophysiology 13
2.5 DNMTP task 14
2.6 Data analysis and statistics 14
III. RESULTS
3.1 Frontoparietal connectivity between PFC and PPC 14
3.2. Frontoparietal activity is necessary during short-term memory 15
3.3 Local inhibition of acetylcholine release at PPC showed deficits of short-term memory 16
3.4 The neuronal activity during short-term memory task 19
IV. FIGURES
Figure 1. Connectivity between PFC and PPC
Figure 2. Electrical stimulation of PFC increased in the firing rate of the PPC.
Figure 3. Photoinhibition frontoparietal activity showed deficits of short-term memory.
Figure 4. Inhibition of Acetylcholine release in PPC showed deficits of short-term memory.
Figure 5. Unit sorting process
Figure 6. The frequency difference between correct and incorrect trials during delay period
Figure 7. Statistical comparison of frequency between correct and incorrect trialsMasterdCollectio
Triboelectric nanogenerator for self-powered traffic monitoring
No full textThis work aims to create energy-harvesting composites using poly(ethylene-co-vinyl acetate) EVA, lead zirconate titanate (PZT) and polyaniline (PANI) composites. The novelty lies in the fabrication of a triboelectric nanogenerator (TENG) using EVA-PZT-PANI composites. These composites combine the flexibility of EVA polymer with the electricity-generating power of PZT ceramic and the conductivity of PANI. Systematic investigation of the structural, electrical, and microstructural properties of these composites is carried out to optimize their energy-harvesting performance. Among various compositions, the EVP3 device demonstrates exceptional output, generating a peak voltage of 17.8 V and a current of 190 nA at 2 Hz and 5 N applied force. The TENG demonstrates its versatility in harvesting energy from various sources by powering capacitors and collecting energy from human motions. Moreover, we show the potential application of the TENG for real-time traffic monitoring. By embedding the TENG into roads, we can measure car speeds and serve as a traffic management counter, opening up new possibilities for self-powered intelligent transportation systems. © 2024 Elsevier B.V.FALSEsciescopu
Role of Boron Content in CoFeB Thin Films on the Microstructure and Magnetic Exchange Interactions
No full textCoFeB;Exchange stiffness constant (Aex);Interfacial Dzyaloshinskii-Moriya interaction (iDMI);Brillouin light scattering (BLS)Ⅰ. Introduction 1
Ⅱ. Theorical Background 5
2.1. Energies in magnetic system 6
2.1.1. Heisenberg exchange interaction 6
2.1.2. Dzyaloshinskii-Moriya interaction 7
2.2.3. Shape anisotropy 8
2.2.4. Interfacial magnetic anisotropy 8
2.2.5. Perpendicular magnetic anisotropy 9
2.3.6. Zeeman energy 9
2.2. Brillouin light scattering (BLS) 10
2.2.1. Landau-Lifshitz-Gilbert (LLG) equation 10
2.2.2. Spin wave 12
2.2.3. Equations for spin wave modes in the magnetic thin films 14
2.2.4. Inelastic scattered light 16
2.2.5. Brillouin light scattering 17
Ⅲ. Experimental Techniques 18
3.1. Thin Film deposition 19
3.2. Brillouin light scattering spectroscopy (BLS) 21
3.2.1. Single Fabry-Pérot interferometer (FPI) 21
3.3.2. Tandem Fabry-Pérot interferometer (FPI) 24
Ⅳ. Research Theme 1 26
4.1. Overview 27
4.2. Materials and Methods 27
4.3. Results and discussion 31
4.4. Conclusion 42
4.5. Appendix 43
Ⅴ. Research Theme 2 53
5.1. Overview 54
5.2. Materials and Methods 56
5.3. Results and discussion 57
5.4. Conclusion 58
5.5. Appendix 73
Ⅶ. Reference 86DoctordCollectio
A Self-Powered Smart White Cane for Improving Mobility of Visually Impaired Person Using a Triboelectric Nanogenerator
No full textThe present research offers an innovative approach to enhance the safety and mobility of people with visual impairments by using a smart white cane sensor. Herein, an aluminum electrode, Kapton film, and an inexpensive PET substrate are employed to develop an origami-shaped multilayered triboelectric nanogenerator (TENG) device. The multilayered integration of three-unit TENGs produces output with a high power of 51 μW at 50 MΩ, along with 155 V and 4.5 μA. Capacitor charging, low-power electronics powering, and the integration of mechanoluminescent materials are demonstrated. The integration of mechanoluminescent materials enables efficient identification of visually impaired people in regions with poor lighting. A single-electrode TENG is also implemented for successful surface material detection. To further enhance the sensor's capabilities, digital signal processing techniques are employed for obstacle recognition on their route. The intelligent white cane sensor effectively detects obstructions, offering the user instantaneous feedback and enabling more secure navigation in sophisticated environments. This study highlights the possibility of integrating TENG technologies to provide a complete solution for people with visual impairments. The smart white cane sensor has the potential to greatly increase the safety and independence of visually impaired people in a variety of outdoor and public spaces. © 2024 The Authors. Energy Technology published by Wiley-VCH GmbH This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.TRUEsciescopu
이산화탄소 전기환원을 위한 금속-유기 골격체에서 구리 활성 부위의 재건 현상 규명
No full textMetal-Organic Frameworks;Cu active sites;Reconstruction;Electrochemical CO2 reductionAbstract i
List of Contents ii
List of Tables iv
List of Figures v
Ⅰ. Introduction
1.1 Electrochemical CO2 Reduction Reaction 1
1.2 Cu-based Electrocatalyst for CO2RR 4
1.3 Metal-Organic Frameworks 4
1.4 Reconstruction of Cu-based Catalyst 6
1.5 Research Motivation and Strategy 7
Ⅱ. Theoretical Background
2.1 Fundamental Theory of Electrochemical CO2RR 9
2.1.1 Electrochemical Reaction 9
2.1.2 Mechanisms of CO2 Reduction 9
2.1.3 Performance Evaluation Indicators of CO2 Reduction Catalyst 12
2.2 CO2RR Electrolyzer 14
2.2.1 Development of GDE 14
2.2.2 Characteristics of Flow-type Cell 14
2.3 Chemical State Transformation of Cu 17
2.3.1 Change of Cu State by Alkaline Electrolyte 17
2.3.2 Change of Cu State by Reduction Potential 19
Ⅲ. Experimental
3.1 Material Synthesis 21
3.1.1 Synthesis of Cu-BTC and Cu-BDC 21
3.1.2 Fabrication of Cu/C-BTC and Cu/C-BDC 22
3.1.3 Fabrication of i-Cu-BTC and i-Cu-BDC 22
3.2 Material Characterization 22
3.3 Electrode Preparation 23
3.4 Evaluation of CO2 Reduction Performance 24
Ⅳ. Results and Discussion
4.1 Reconstruction of Cu active sites based on morphology and Cu initial state 25
4.1.1 Catalyst Synthesis and Characterization 25
4.1.2 CO2RR Performance Evaluation 46
4.1.3 Real-time Analysis of Reaction Intermediates 49
4.2 Unveiling the Reconstruction of Cu Active Sites in MOFs 51
4.2.1 Strategy for Revealing the Reconstruction Mechanism of MOFs 51
4.2.2 Characterization of i-Cu-BTC and i-Cu-BDC 53
4.2.3 CO2RR Performance Evaluation 63
4.2.4 Proposed MOFs Reconstruction Mechanism 65
V. Conclusion 67
VI. Reference 68
요약문 71MasterdCollectio
YAP1 regulates esophageal stem cells’ self-renewal and differentiation
No full textEsophageal epithelium is one of the most proliferative and regenerative epithelia in our body, indicating robust stem cell activity. However, the underlying mechanisms regulating the self-renewal and differentiation of esophageal stem cells need to be more elucidated. Here, we identify the role of YAP1 in esophageal stem cells. YAP1 is differentially expressed in the nuclei of esophageal basal cells. Furthermore, the treatment of verteporfin, a YAP1 inhibitor, interfered with esophageal organoid formation. Consistently, YAP1 deletion decreased esophageal organoid formation and the expression of basal genes while increasing the expression of suprabasal genes. Finally, global transcriptomic analysis revealed that YAP1 inhibition induced a significant enrichment of gene sets related to keratinization and cornification, while depleting gene sets related to DNA repair and chromosome maintenance. Our data uncover a novel regulatory mechanism for esophageal stem cells, which could provide a potential strategy for esophageal regenerative medicine.© 2024FALSEsciescopu