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Search Results: 1 - 10 of 1450 matches for " Minchul Seo "
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Time-dependent effects of hypothermia on microglial activation and migration
Jung-Wan Seo, Jong-Heon Kim, Jae-Hong Kim, Minchul Seo, Hyung Soo Han, Jaechan Park, Kyoungho Suk
Journal of Neuroinflammation , 2012, DOI: 10.1186/1742-2094-9-164
Abstract: Microglial cells in culture were subjected to mild (33?°C) or moderate (29?°C) hypothermic conditions before, during, or after lipopolysaccharide (LPS) or hypoxic stimulation, and the production of nitric oxide (NO), proinflammatory cytokines, reactive oxygen species, and neurotoxicity was evaluated. Effects of hypothermia on microglial migration were also determined in in vitro as well as in vivo settings.Early-, co-, and delayed-hypothermic treatments inhibited microglial production of inflammatory mediators to varying degrees: early treatment was the most efficient, and delayed treatment showed time-dependent effects. Delayed hypothermia also suppressed the mRNA levels of proinflammatory cytokines and iNOS, and attenuated microglial neurotoxicity in microglia-neuron co-cultures. Furthermore, delayed hypothermia reduced microglial migration in the Boyden chamber assay and wound healing assay. In a stab injury model, delayed local hypothermia reduced migration of microglia toward the injury site in the rat brain.Taken together, our results indicate that delayed hypothermia is sufficient to attenuate microglial activation and migration, and provide the basis of determining the optimal time window for therapeutic hypothermia. Delayed hypothermia may be neuroprotective by inhibiting microglia-mediated neuroinflammation, indicating the therapeutic potential of post-injury hypothermia for patients with brain damages exhibiting some of the inflammatory components.
Spin filter using a semiconductor quantum ring side-coupled to a quantum wire
Minchul Lee,C. Bruder
Physics , 2005, DOI: 10.1103/PhysRevB.73.085315
Abstract: We introduce a new spin filter based on spin-resolved Fano resonances due to spin-split levels in a quantum ring (QR) side-coupled to a quantum wire (QW). Spin-orbit coupling inside the QR, together with external magnetic fields, induces spin splitting, and the Fano resonances due to the spin-split levels result in perfect or considerable suppression of the transport of either spin direction. Using the numerical renormalization group method, we find that the Coulomb interaction in the QR enhances the spin filter operation by widening the separation between dips in conductances for different spins and by allowing perfect blocking for one spin direction and perfect transmission for the other. The spin-filter effect persists as long as the temperature is less than the broadening of QR levels due to the QW-QR coupling. We discuss realistic conditions for the QR-based spin filter and its advantages to other similar devices.
Current-Conserving Aharonov-Bohm Interferometry with Arbitrary Spin Interactions
Minchul Lee,Dimitrije Stepanenko
Physics , 2011, DOI: 10.1103/PhysRevB.85.075316
Abstract: We propose a general scattering matrix formalism that guarantees the charge conservation at junctions between conducting arms with arbitrary spin interactions. By using our formalism, we find that the spin-flip scattering can happen even at nonmagnetic junctions if the spin eigenstates in arms are not orthogonal. We apply our formalism to the Aharonov-Bohm interferometer consisting of $n$-type semiconductor ring with both the Rashba spin-orbit coupling and the Zeeman splitting. We discuss the characteristics of the interferometer as conditional/unconditional spin switch in the weak/strong-coupling limit, respectively.
Charge and spin density modulations in semiconductor quantum wires
Minchul Lee,Christoph Bruder
Physics , 2005, DOI: 10.1103/PhysRevB.72.045353
Abstract: We investigate static charge and spin density modulation patterns along a ferromagnet/semiconductor single junction quantum wire in the presence of spin-orbit coupling. Coherent scattering theory is used to calculate the charge and spin densities in the ballistic regime. The observed oscillatory behavior is explained in terms of the symmetry of the charge and spin distributions of eigenstates in the semiconductor quantum wire. Also, we discuss the condition that these charge and spin density oscillations can be observed experimentally.
Correspondences and Quantum Description of Aharonov-Bohm and Aharonov-Casher Effects
Minchul Lee,M. Y. Choi
Physics , 2003, DOI: 10.1088/0305-4470/37/3/029
Abstract: We establish systematic consolidation of the Aharonov-Bohm and Aharonov-Casher effects including their scalar counterparts. Their formal correspondences in acquiring topological phases are revealed on the basis of the gauge symmetry in non-simply connected spaces and the adiabatic condition for the state of magnetic dipoles. In addition, investigation of basic two-body interactions between an electric charge and a magnetic dipole clarifies their appropriate relative motions and discloses physical interrelations between the effects. Based on the two-body interaction, we also construct an exact microscopic description of the Aharonov-Bohm effect, where all the elements are treated on equal footing, i.e., magnetic dipoles are described quantum-mechanically and electromagnetic fields are quantized. This microscopic analysis not only confirms the conventional (semiclassical) results and the topological nature but also allows one to explore the fluctuation effects due to the precession of the magnetic dipoles with the adiabatic condition relaxed.
Analysis of Awareness and Utilization of BIM in Civil Engineering  [PDF]
MyoungBae Seo, JinUk Kim
Open Journal of Applied Sciences (OJAppS) , 2012, DOI: 10.4236/ojapps.2012.24B038
Abstract: Recently, Building Information Modeling (BIM) has emerged as a hot topic in the construction industry. However, the application of civil engineering, both domestic and foreign, is minor because of the distribution in a wide area, highly liner dependence and difficulty to take advantage of the standard library.? Civil engineering requires a lot of time and financial resources compared to architectural engineering. If BIM is completely applied to civil engineering, it will be possible to manage the schedule and cost using 3D and facilitates effective communication between various stakeholders. For the application of BIM in civil engineering, we surveyed the awareness, utilization and effectiveness of BIM on the civil engineering companies. Also, we derived necessary improvements and analyzed new business areas for BIM application. The results of the study will be used as a reference of development for SOC civil engineering BIM ordering guide and related standard.
Korea’s Construction Business Informatization Overview  [PDF]
MyoungBae Seo, NamGon Kim
Open Journal of Applied Sciences (OJAppS) , 2012, DOI: 10.4236/ojapps.2012.24B004
Abstract: South Korea’s construction industry won orders worth USD 58 billion in 2011, and as such, it has achieved a remarkable growth. However, despite such an impressive quantitative growth, value-added quality growth has been very slow. Thus, the Ministry of Land, Transport and Marine Affairs (MLTM) is pushing ahead with the construction informatization initiative (Construction Continuous Acquisition & Life-cycle Support - CALS) in order to systematically manage a wide range of construction information by stage and to enhance the efficiency of construction costs. This study aims to review the country’s construction CALS to explore a construction development direction.
Effectiveness of Endovascular Coil Embolization of Ruptured Hepatic Artery Pseudoaneurysm  [PDF]
Jung Wook Seo
Advances in Computed Tomography (ACT) , 2017, DOI: 10.4236/act.2017.62002
Abstract: Purpose: To assess the efficacy of endovascular management for ruptured hepatic artery pseudoaneurysm (HAP). Methods: Six cases of HAP in five patients (four men and one women; mean age, 50; range, 28 - 62) were treated with transcatheter arterial coil embolization using microcoil (Boston Scientific, Watertown, MA, USA) and Tornado Coil (Cook, Bloomington, IN, USA) with or without stent graft between January 2007 and September 2008. They were analyzed with regard to the clinical presentation, radiological findings with procedure, and clinical and radiologic outcomes. Results: All patients presented with epigastric pain or gastrointestinal bleeding. The pseudoaneurysms were ranged from 0.6 to 4.4 cm in size and located in the common hepatic artery (n = 1), junction between proper and right hepatic artery (n = 1), proper hepatic artery (n = 2), the left hepatic artery (n = 1), right hepatic artery (n = 1). Embolization was performed with microcoils in all pseudoaneurysmal sac with or without both afferent and efferent segment. A self-expandable stent (n = 1) was also used. Overall technical success was 100% (6 of 6) and complete occlusions of HAPs were achieved in 5 out of 6 cases, 83.3% of clinical success rate. Re-bleeding occurred in one case of stent graft at proper hepatic artery following coil packing for pseudoaneurysmal sac. Clinical success rate of embolization for both afferent and efferent segment was 100% (3 of 3). Procedure-related minor complications happened in 2 of 5 patients, and they were treated conservatively. Conclusion: Transcatheter coil embolization for ruptured HAP is sufficiently effective and additional embolization in both afferent segment and efferent segment can improve clinical success rate.
Acute Epiploic Appendagitis of the Vermiform Appendix: Typical Computed Tomographic Image with Pathologic Correlation  [PDF]
Jung Wook Seo
Advances in Computed Tomography (ACT) , 2017, DOI: 10.4236/act.2017.64004
Epiploic appendages can become ischemic and infarcted, which can present acute abdominal pain that mimics other diseases, such as diverticulitis or appendicitis. Particularly, inflammation of an epiploic appendage attached to the vermiform appendix is a very rare cause of acute abdominal pain, and it is difficult to diagnose this condition preoperatively. We present a case of epiploic appendagitis of the vermiform appendix that was identified with a typical radiologic image and was pathologically confirmed. In addition, we review the literature of similar cases and analyze the clinical and radiologic features of EA of the vermiform appendix.
Josephson Effect through an isotropic magnetic molecule
Minchul Lee,Thibaut Jonckheere,Thierry Martin
Physics , 2008, DOI: 10.1103/PhysRevLett.101.146804
Abstract: We investigate the Josephson effect through a molecular quantum dot magnet connected to superconducting leads. The molecule contains a magnetic atom, whose spin is assumed to be isotropic. It is coupled to the electron spin on the dot via exchange coupling. Using the numerical renormalization group method we calculate the Andreev levels and the supercurrent and examine intertwined effect of the exchange coupling, Kondo correlation, and superconductivity on the current. Exchange coupling typically suppresses the Kondo correlation so that the system undergoes a phase transition from 0 to $\pi$ state as the modulus of exchange coupling increases. Antiferromagnetic coupling is found to drive exotic transitions: the reentrance to the $\pi$ state for a small superconducting gap and the restoration of 0 state for large antiferromagnetic exchange coupling. We suggest that the asymmetric dependence of supercurrent on the exchange coupling could be used as to detect its sign in experiments.
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