56 research outputs found
Correction: Goo, S.; Yang, H.-D. Restoring Raindrops Using Attentive Generative Adversarial Networks. <i>Appl. Sci.</i> 2021, <i>11</i>, 7034
No full textSuhan Goo was not included as an author in the original publication [...
= Mn, Ni, Fe)
No full text© 2020 Author(s). We investigated the thermal transport properties of magnetic van der Waals materials, TMPS3 (TM = Mn, Ni, and Fe), using the time-domain thermoreflectance technique. We determined the cross-plane thermal conductivity, which turns out to be relatively low, i.e., about 1W m(-1) K-1 for all TMPS3 investigated. When compared with previous results of graphite and transition metal dichalcogenides (TMDs), thermal conductivity becomes smaller as it goes from graphite to TMDs to TMPS3, and the difference is larger at low temperature, e.g., around 50K. From the Callaway model analysis, we could attribute the large thermal conductivity reduction for TMPS3, particularly at low temperature, to the phonon scattering from the boundary. We actually confirmed the existence of the large population of the stacking faults with the cross-sectional transmission electron microscopy image of MnPS3. This suggests that intrinsic or extrinsic stacking faults formed in van der Waals materials and their heterostructures can play an important role in reducing the cross-plane thermal conductivity as a source of the boundary scattering11sci
저항성 운동이 C57BL/6N 쥐의 근육과 뼈의 질에 미치는 영향: Fibroblast Growth Factor Signaling에 관하여
No full text학위논문 (석사)-- 서울대학교 대학원 : 체육교육과, 2017. 2. 송욱.서론:
근육의 질과 뼈의 질을 좋은 상태로 유지하는 것은 노년의 삶의 질 향상과 밀접한 연관성을 지닌다. 규칙적인 운동은 근육뿐만 아니라 뼈의 질 향상에 중요한 역할을 지니는 것으로 알려져 있다. 하지만 운동으로 인해 유도되는 상호작용의 기전에 대해서는 잘 알려져 있지 않다.
근육과 뼈는 서로 이웃한 기관으로써 기능적으로 밀접한 관계를 지닌다. 여러 선행 논문에 따르면 근육과 뼈의 상호 커뮤니케이션에 있어서 마이오카인(myokine)이 잠정적인 중재자 역할을 할 것이라고 얘기하고 있다. 이 중 FGF-2는 저항성 운동을 통해 분비될 것으로 기대되며, FGF 수용체에 결합하여 뼈의 질에 긍정적인 영향을 미칠 신호전달을 유도할 것이라고 사료된다.
따라서 이 연구에서는 FGF-2와 FGFR 신호전달 체계가 저항성 운동으로 인해 유도되는 근육과 뼈의 질 향상에 중요한 역할을 하는지 알아보고자 하였다. 이를 확인하기 위해 FGFR 억제 물질을 투여하여 정확한 사실관계를 확인하고자 하였다.
방법:
성장기의 8주령 C57BL/6N 쥐를 다음과 같이 임의로 분배하였다억제 물질 투여 통제군 (Inh-C), vehicle 물질 투여 통제군 (Sham-C), 저항성 운동과 억제물질 투여군 (RT-Inh), 저항성 운동과 vehicle 물질 투여군 (Sham-C). FGFR 억제 물질로는 NVP-BGJ398 (50mg/kg body weightNovartis, Switzerland)가 사용되었으며, vehicle로는 PEG-300을 Glucose 5% 와 2:1 비율로 혼합하여 사용하였다.
저항성운동은 주 3회의 빈도로 8주간 실시 되었으며, 매주 몸무게, 악력을 측정하였고, 마지막 운동 프로그램 종료 시점으로부터 48시간 후 운동관련 지표를 측정하였다. 운동관련 지표 측정 후 48시간의 회복기간을 가진 다음 근육과 뼈, 그리고 장기를 적출하여 생물학적 지표를 분석하였다.
결과:
FGFR 억제 물질 투여군은 악력, 근지구력, 심폐지구력 관련 지표를 저하시키는 것으로 나타났다. 신체 조성과 근육 무게는 크게 영향을 미치지 않는 것으로 나타났다. 이 효과는 운동군에서도 동일하게 나타났으며, 운동으로 인해 나타나는 근력 증가와 근 지구력 향상, 뼈의 질 증가는 FGFR 억제 물질 투여로 인해 억제되는 것으로 나타났다.
억제물질 투여는 뼈의 질 또한 유의미하게 낮추는 것으로 나타났으며, FGF2 유전자와 myostatin 유전자 발현 또한 근육과 뼈에서 낮추는 것으로 나타났다.
결론:
FGFR 억제 물질은 근육의 질과 뼈의 질을 낮추며, 이 효과는 8주간의 저항성 운동으로 인해 회복되지 않는 것으로 나타났다. Myostatin과 FGF2의 유전자 발현은 근육과 뼈에서 상반되는 발현양상을 보였으며, 이는 이 연구의 가설과는 다른 결과를 도출하였다. 운동과 FGFR 억제 물질, 그리고 유전자 발현의 관계를 정확히 규명하기 위해서는 추가적인 실험이 필요할 것으로 사료된다.Many studies identified that muscle and bone are functionally interlinked to one another and maintain the quality and strength of muscle and bone are important for quality of human life. Here, I examine the relationship linking Fibroblast growth factors, potential candidates for the role player in muscle and bone cross talk, to bone and muscle quality during growth and resistance exercise. To elucidate the relationship and potential role of FGFs and its signaling, FGFR inhibitor was used while 8 weeks of resistance training was conducted.
Administration of FGFR inhibitor decreased grip strength, reduced muscular endurance and running capacity. 8 weeks of inhibitor treatment did not affect muscle mass, body weight or body composition. Inhibitor treatment showed no difference with resistance trained group while the group without inhibitor treatment with exercise showed significant increase in grip strength, muscular and aerobic endurance capacity and maximal load lifted during session. RT-Sham group solely showed hind limb muscle mass increments. FGF2 gene expression responded to resistance training in gastrocnemius muscle but, did not respond much in tibia. However, FGF2 gene expression in tibia exhibited the change in much larger scale than gastrocnemius muscle when inhibitor were treated. Myostatin gene expression in bone and muscle responded opposite to each other with 8 weeks of resistance training.
FGFR inhibitor treatment in normal and exercise condition both attenuated muscular strength, endurance and aerobic endurance capacity. 8 weeks of resistance training could not restore the detrimental effects, however seemed to affect FGF-2 mRNA expression in bone. Myostatin responded to resistance training and inhibitors in gastrocnemius muscle but one responded to resistance training in bone tissue. Further analysis is needed to elaborate the definite correlation between gene expressions and resistance training with or without inhibitor treatment.I. INTRODUCTION 1
1. Significance of the Study 1
2. Purpose of the Study 3
3. Research Hypothesis 3
II. LITERATURE REVIEW 4
1. Resistance Exercise Models of Animal 4
2. Resistance Exercise and Bone Quality 5
3. Fibroblast Growth Factor-2 and Bone 6
4. Fibroblast Growth Factor Signaling in Bone Formation 7
III. METHODS 8
1. Animal Model 8
2. Experimental Design 8
3. Exercise Apparatus and Protocol 10
4. Grip Strength Test 12
5. Muscular Endurance Capacity Test 13
6. Aerobic Endurance Capacity Test 14
7. Skeletal Muscle Dissection 15
8. Molecular Biological Analysis 16
9. MicroCT and PetCT analysis 18
IV. RESULT 19
1. Effect of FGFR Inhibitor (NVP-BGJ398) on Growth Adaptation 19
2. Effect of FGFR Inhibitor (NVP-BGJ398) on Resistance Training Adaptation 22
3. FGF-2 and Myostatin Expression on Muscle and Bone 24
4. Effect of Resistance training and FGFR Inhibitor on Bone Quality 26
V. DISCUSSION 28
VI. CONCLUSION 33
VII. REFERENCE 34
국문초록 40Maste
Observation of plateau-like magnetoresistance in twisted Fe3GeTe2/Fe3GeTe2 junction
No full text© 2020 Author(s). Controlling the stacking of van der Waals (vdW) materials is found to produce exciting new findings, since hetero- or homo-structures have added the diverse possibility of assembly and manipulated functionalities. However, so far, the homostructure with a twisted angle based on the magnetic vdW materials remains unexplored. Here, we achieved a twisted magnetic vdW Fe3GeTe2 (FGT)/Fe3GeTe2 junction with broken crystalline symmetry. A clean and metallic vdW junction is evidenced by the temperature-dependent resistance and the linear I-V curve. Unlike the pristine FGT, a plateau-like magnetoresistance (PMR) is observed in the magnetotransport of our homojunction due to the antiparallel magnetic configurations of the two FGT layers. The PMR ratio is found to be similar to 0.05% and gets monotonically enhanced as temperature decreases like a metallic giant magnetoresistance. Such a tiny PMR ratio is at least three orders of magnitude smaller than the tunneling magnetoresistance ratio, justifying our clean metallic junction without a spacer. Our findings demonstrate the feasibility of the controllable homostructure and shed light on future spintronics using magnetic vdW materials. Published under license by AIP Publishing11sciescopu
Isostructural Mott transition in 2D honeycomb antiferromagnet V0.9PS3
No full text© 2019, The Author(s).The MPX3 family of magnetic van-der-Waals materials (M denotes a first row transition metal and X either S or Se) are currently the subject of broad and intense attention for low-dimensional magnetism and transport and also for novel device and technological applications, but the vanadium compounds have until this point not been studied beyond their basic properties. We present the observation of an isostructural Mott insulator–metal transition in van-der-Waals honeycomb antiferromagnet V0.9PS3 through high-pressure x-ray diffraction and transport measurements. We observe insulating variable-range-hopping type resistivity in V0.9PS3, with a gradual increase in effective dimensionality with increasing pressure, followed by a transition to a metallic resistivity temperature dependence between 112 and 124 kbar. The metallic state additionally shows a low-temperature upturn we tentatively attribute to the Kondo effect. A gradual structural distortion is seen between 26 and 80 kbar, but no structural change at higher pressures corresponding to the insulator–metal transition. We conclude that the insulator–metal transition occurs in the absence of any distortions to the lattice—an isostructural Mott transition in a new class of two-dimensional material, and in strong contrast to the behavior of the other MPX3 compounds11sciescopu
Exciton-driven antiferromagnetic metal in a correlated van der Waals insulator
No full text© 2021, The Author(s).Collective excitations of bound electron-hole pairs—known as excitons—are ubiquitous in condensed matter, emerging in systems as diverse as band semiconductors, molecular crystals, and proteins. Recently, their existence in strongly correlated electron materials has attracted increasing interest due to the excitons’ unique coupling to spin and orbital degrees of freedom. The non-equilibrium driving of such dressed quasiparticles offers a promising platform for realizing unconventional many-body phenomena and phases beyond thermodynamic equilibrium. Here, we achieve this in the van der Waals correlated insulator NiPS3 by photoexciting its newly discovered spin–orbit-entangled excitons that arise from Zhang-Rice states. By monitoring the time evolution of the terahertz conductivity, we observe the coexistence of itinerant carriers produced by exciton dissociation and a long-wavelength antiferromagnetic magnon that coherently precesses in time. These results demonstrate the emergence of a transient metallic state that preserves long-range antiferromagnetism, a phase that cannot be reached by simply tuning the temperature. More broadly, our findings open an avenue toward the exciton-mediated optical manipulation of magnetism.11Nsciescopu
Chemoresistance acquisition induces a global shift of expression of aniogenesis-associated genes and increased pro-angogenic activity in neuroblastoma cells
No full textBACKGROUND: Chemoresistance acquisition may influence cancer cell biology. Here, bioinformatics analysis of gene expression data was used to identify chemoresistance-associated changes in neuroblastoma biology. RESULTS: Bioinformatics analysis of gene expression data revealed that expression of angiogenesis-associated genes significantly differs between chemosensitive and chemoresistant neuroblastoma cells. A subsequent systematic analysis of a panel of 14 chemosensitive and chemoresistant neuroblastoma cell lines in vitro and in animal experiments indicated a consistent shift to a more pro-angiogenic phenotype in chemoresistant neuroblastoma cells. The molecular mechanims underlying increased pro-angiogenic activity of neuroblastoma cells are individual and differ between the investigated chemoresistant cell lines. Treatment of animals carrying doxorubicin-resistant neuroblastoma xenografts with doxorubicin, a cytotoxic drug known to exert anti-angiogenic activity, resulted in decreased tumour vessel formation and growth indicating chemoresistance-associated enhanced pro-angiogenic activity to be relevant for tumour progression and to represent a potential therapeutic target. CONCLUSION: A bioinformatics approach allowed to identify a relevant chemoresistance-associated shift in neuroblastoma cell biology. The chemoresistance-associated enhanced pro-angiogenic activity observed in neuroblastoma cells is relevant for tumour progression and represents a potential therapeutic target
Air-Stable and Layer-Dependent Ferromagnetism in Atomically Thin van der Waals CrPS4
No full text© 2021 American Chemical Society.Ferromagnetism in two-dimensional materials presents a promising platform for the development of ultrathin spintronic devices with advanced functionalities. Recently discovered ferromagnetic van der Waals crystals such as CrI3, readily isolated two-dimensional crystals, are highly tunable through external fields or structural modifications. However, there remains a challenge because of material instability under air exposure. Here, we report the observation of an air-stable and layer-dependent ferromagnetic (FM) van der Waals crystal, CrPS4, using magneto-optic Kerr effect microscopy. In contrast to the antiferromagnetic (AFM) bulk, the FM out-of-plane spin orientation is found in the monolayer crystal. Furthermore, alternating AFM and FM properties observed in even and odd layers suggest robust antiferromagnetic exchange interactions between layers. The observed ferromagnetism in these crystals remains resilient even after the air exposure of about a day, providing possibilities for the practical applications of van der Waals spintronics.11Nsciescopu
Thermally Stable Antireflective Coatings Based on Nanoporous Organosilicate Thin Films
No full textThermally stable nanoporous organosilicate thin films were realized by the microphase separation of pore-generating polymers mixed with an organosilicate matrix to be antireflective coatings (ARCs), for which a thin film with a refractive index (n) of 1.23 for zero reflection is required. The refractive index of such nanoporous organosilicate films can be tuned from 1.39 down to 1.23 by incorporating nanopores within the films. With a nanoporous single layer with n ~ 1.23, the light transmittance of the glass above 99.8% was achieved in the visible range (λ ~ 550 nm). To overcome the limitation on the narrow wavelength for high transmittance imposed by a single antireflective nanoporous thin film, bilayer thin films with different refractive indices were prepared by placing a high refractive index layer with a refractive index of 1.45 below the nanoporous thin film. UV−vis transmittance of a glass coated with the bilayer films was compared with nanoporous single-layer films and it is demonstrated that the novel broadband antireflection coatings in a wide range of visible wavelength can be easily obtained by the organosilicate bilayer thin films described in this study. Also, ARCs developed in this study demonstrate excellent AR durability owing to the hydrophobic nature of the organosilicate matrix.This work was supported by the NANO Systems Institute - National Core Research Center (NSI-NCRC) from the Korea Science and Engineering Foundation (KOSEF) and the Brain Korea 21 Program endorsed by the Ministry of Education of Korea. We are very grateful to Mr. Y. J. Park at Postech for assistance during X-ray reflectivity experiments at Pohang Light Source (PLS) supported by the Ministry of Science and Technology of Korea.Wealso thank Dr. Steve Kline (NIST), Prof. S.-M. Choi, and Mr. J. Lee for their help during smallangle
neutron scattering experiments at the National Institute of Standards and Technology (NIST) in the United States. J.C. acknowledges the financial support from the ERC Program of the MOST/ KOSEF (R11-2005-048-00000-0)
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