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Search Results: 1 - 10 of 44202 matches for " Yong Seung Kim "
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Quantitative Measurement of Elasticity of the Appendix Using Shear Wave Elastography in Patients with Suspected Acute Appendicitis
Seung-Whan Cha, Ik Yong Kim, Young Wan Kim
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0101292
Abstract: Introduction Shear wave elastography (SWE) has not been studied for diagnosing appendicitis. We postulated that an inflamed appendix would become stiffer than a normal appendix. We evaluated the elastic modulus values (EMV) by SWE in healthy volunteers, patients without appendicitis, and patients with appendicitis. We also evaluated diagnostic ability of SWE for differentiating an inflamed from a normal appendix in patients with suspected appendicitis. Materials and Methods Forty-one patients with clinically suspected acute appendicitis and 11 healthy volunteers were prospectively enrolled. Gray-scale ultrasonography (US), SWE and multi-slice computed tomography (CT) were performed. The EMV was measured in the anterior, medial, and posterior appendiceal wall using SWE, and the highest value (kPa) was recorded. Results Patients were classified into appendicitis (n = 30) and no appendicitis groups (n = 11). One case of a negative appendectomy was detected. The median EMV was significantly higher in the appendicitis group (25.0 kPa) compared to that in the no appendicitis group (10.4 kPa) or in the healthy controls (8.3 kPa) (p<0.001). Among SWE and other US and CT features, CT was superior to any conventional gray-scale US feature or SWE. Either the CT diameter criterion or combined three CT features predicted true positive in 30 and true negative in 11 cases and yielded 100% sensitivity and 100% specificity. An EMV of 12.5 kPa for the stiffest region of the appendix predicted true positive in 28, true negative in 11, and false negative in two cases. The EMV (≥12.5 kPa) yielded 93% sensitivity and 100% specificity. Conclusion Our results suggest that EMV by SWE helps distinguish an inflamed from a normal appendix. Given that SWE has high specificity, quantitative measurement of the elasticity of the appendix may provide complementary information, in addition to morphologic features on gray-scale US, in the diagnosis of appendicitis.
Distinct mechanisms of DNA sensing based on N-doped carbon nanotubes with enhanced conductance and chemical selectivity
Han Seul Kim,Seung Jin Lee,Yong-Hoon Kim
Physics , 2012, DOI: 10.1002/smll.201301225
Abstract: Carrying out first-principles calculations, we study N-doped capped carbon nanotube (CNT) electrodes applied to DNA sequencing. While we obtain for the face-on nucleobase junction configurations a conventional conductance ordering where the largest signal results from guanine according to its high highest occupied molecular orbital (HOMO) level, we extract for the edge-on counterparts a distinct conductance ordering where the low-HOMO thymine provides the largest signal. The edge-on mode is shown to operate based on a novel molecular sensing mechanism that reflects the chemical connectivity between N-doped CNT caps that can act both as electron donors and electron acceptors and DNA functional groups that include the hyperconjugated thymine methyl group.
A Study on Effective System for Harbor Container Delivery & Cargo Work Automatuion  [PDF]
Dong-Hoon Kim, Jun-Yeob Song, Seung-Ho Lee, Il-Yong Kang, Suk-Keun Cha
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.28074
Abstract: In this article, we have attempted to analyze current situation and the problem of domestic and overseas harbor container delivery & cargo work automation centered on major harbors and to suggest effective way to deal with the issue in order to improve the productivity of container cargo work per crane, the major index of productivity of high value-added shipbuilding industry. In particular, we have suggested the way to realize effective automation system that can improve the efficiency of harbor container delivery & cargo work through the development of high-tech measuring automation technology using microwave radar and applied design that have broken away from traditional automation system and traditional problems such as dependence on manual work and the problem of laser method in which workers cannot identify laser beam under sunlight and workers’ eyesight can be weakened by being exposed to laser beam.
Anterior Cranial Base Reconstruction with a Reverse Temporalis Muscle Flap and Calvarial Bone Graft
Seung Gee Kwon,Yong Oock Kim,Dong Kyun Rah
Archives of Plastic Surgery , 2012, DOI: http://dx.doi.org/10.5999/aps.2012.39.4.345
Abstract: Background Cranial base defects are challenging to reconstruct without serious complications.Although free tissue transfer has been used widely and efficiently, it still has the limitation ofrequiring a long operation time along with the burden of microanastomosis and donor sitemorbidity. We propose using a reverse temporalis muscle flap and calvarial bone graft as analternative option to a free flap for anterior cranial base reconstruction.Methods Between April 2009 and February 2012, cranial base reconstructions using anautologous calvarial split bone graft combined with a reverse temporalis muscle flap wereperformed in five patients. Medical records were retrospectively analyzed and postoperativecomputed tomography scans, magnetic resonance imaging, and angiography findings wereexamined to evaluate graft survival and flap viability.Results The mean follow-up period was 11.8 months and the mean operation time forreconstruction was 8.4±3.36 hours. The defects involved the anterior cranial base, includingthe orbital roof and the frontal and ethmoidal sinus. All reconstructions were successful. Viableflap vascularity and bone survival were observed. There were no serious complications exceptfor acceptable donor site depressions, which were easily corrected with minor procedures.Conclusions The reverse temporalis muscle flap could provide sufficient bulkiness to fill deadspace and sufficient vascularity to endure infection. The calvarial bone graft provides a rigidframework, which is critical for maintaining the cranial base structure. Combined anteriorcranial base reconstruction with a reverse temporalis muscle flap and calvarial bone graftcould be a viable alternative to free tissue transfer.
Simple self-gettering differential-pump for minimizing source oxidation in oxide-MBE environment
Yong-Seung Kim,Namrata Bansal,Seongshik Oh
Physics , 2011, DOI: 10.1116/1.3591384
Abstract: Source oxidation of easily oxidizing elements such as Ca, Sr, Ba, and Ti in an oxidizing ambient leads to their flux instability and is one of the biggest problems in the multi-elemental oxide Molecular Beam Epitaxy technique. Here we report a new scheme that can completely eliminate the source oxidation problem: a self-gettering differential pump using the source itself as the pumping medium. The pump simply comprises a long collimator mounted in front of the source in extended port geometry. With this arrangement, the oxygen partial pressure near the source was easily maintained well below the source oxidation regime, resulting in a stabilized flux, comparable to that of an ultra-high-vacuum environment. Moreover, this pump has a self-feedback mechanism that allows a stronger pumping effectiveness for more easily oxidizing elements, which is a desired property for eliminating the source oxidation problem.
Crucible aperture: an effective way to reduce source oxidation in oxide molecular beam epitaxy process
Yong-Seung Kim,Namrata Bansal,Seongshik Oh
Physics , 2011, DOI: 10.1116/1.3449051
Abstract: Growing multi-elemental complex-oxide structures using an MBE (Molecular Beam Epitaxy) technique requires precise control of each source flux. However, when the component elements have significantly different oxygen affinities, maintaining stable fluxes for easily oxidizing elements is challenging because of a source oxidation problem. Here, using Sr as a test source, we show that a crucible aperture insert scheme significantly reduces the source oxidation in an oxide-MBE environment. The crucible aperture insert was shaped like a disk with a hole at the center and was mounted inside the crucible; it blocks most of the oxygen species coming to the source, thus reducing the source oxidation. However, the depth of the aperture disk was critical for its performance; an ill-positioned aperture could make the flux stability even worse. With an optimally positioned aperture insert, the crucible exhibited more than four times improvement in Sr flux stability, compared to a conventional, non-apertured crucible.
Metal-insulator transition on SrTiO$_{3}$ surface induced by ionic-bombardment
Heiko Gross,Namrata Bansal,Yong-Seung Kim,Seongshik Oh
Physics , 2011, DOI: 10.1063/1.3650254
Abstract: SrTiO$_{3}$ is one of the most popular insulating single-crystal substrates for various complex-oxide thin film growths, because of its good lattice match with many complex oxide films. Here, we show that a common thin film processing technique, argon ion-milling, creates highly conducting layer on the surface of STO, not only at room temperatures but also at cryogenic temperatures at which thermal diffusion is completely suppressed. Systematic \emph{in situ} four-point conductance measurements were taken on single-crystal STO substrates inside vacuum environment. The evolution of metallicity out of insulating STO follows simple models based on oxygen vacancy doping effect. At cryogenic temperatures, ion milling created a thin - but much thicker than the argon-penetration depth - steady-state oxygen-vacant layer, leading to a highly-concentric metallic state. Near room temperatures, however, significant thermal diffusion occurred and the metallic state continuously diffused into the bulk, leaving only low concentraion of electron carriers on the surface. Analysis of the discrepancy between the experiments and the models also provided evidence for vacany clustering, which seems to occur during any vacancy formation process and affects the observed conductance. These observations suggest that the transport properties of films processed on STO substrates using energetic methods such as ion milling need to be taken with caution. On the other hand, if properly controlled, ionic bombardment could be used as a way to create selective conducting layers on the surface of STO for device applications.
Up-regulated expression of l-caldesmon associated with malignancy of colorectal cancer
Kim Kyung-Hee,Yeo Seung-Gu,Kim Won Ki,Kim Dae Yong
BMC Cancer , 2012, DOI: 10.1186/1471-2407-12-601
Abstract: Background Caldesmon (CaD), a major actin-associated protein, is found in smooth muscle and non-muscle cells. Smooth muscle caldesmon, h-CaD, is a multifunctional protein, and non-muscle cell caldesmon, l-CaD, plays a role in cytoskeletal architecture and dynamics. h-CaD is thought to be an useful marker for smooth muscle tumors, but the role(s) of l-CaD has not been examined in tumors. Methods Primary colon cancer and liver metastasis tissues were obtained from colon cancer patients. Prior to chemoradiotherapy (CRT), normal and cancerous tissues were obtained from rectal cancer patients. Whole-tissue protein extracts were analyzed by 2-DE-based proteomics. Expression and phosphorylation level of main cellular signaling proteins were determined by western blot analysis. Cell proliferation after CaD siRNA transfection was monitored by MTT assay. Results The expression level of l-CaD was significantly increased in primary colon cancer and liver metastasis tissues compared to the level in the corresponding normal tissues. In cancerous tissues obtained from the patients showing poor response to CRT (Dworak grade 4), the expression of l-CaD was increased compared to that of good response group (Dworak grade 1). In line with, l-CaD positive human colon cancer cell lines were more resistant to 5-fluorouracil (5-FU) and radiation treatment compared to l-CaD negative cell lines. Artificial suppression of l-CaD increased susceptibility of colon cancer cells to 5-FU, and caused an increase of p21 and c-PARP, and a decrease of NF-kB and p-mTOR expression. Conclusion Up-regulated expression of l-CaD may have a role for increasing metastatic property and decreasing CRT susceptibility in colorectal cancer cells.
Computer Simulation Study of Biopolymer Betanova  [PDF]
Seung-Yeon Kim
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.312002
Abstract:

Betanova is a monomeric, three-stranded antiparallel beta-sheet protein with twenty residues. The pathways between the folded native structure and unfolded conformations of betanova are studied using UNRES force field and the most popular computer simulation method, Metropolis Monte Carlo algorithm. At a fixed temperature, 100 Monte Carlo simulations are performed, starting from the folded native structure, and the pathways are obtained at two different temperatures.

Folding and Unfolding Simulations of a Three-Stranded Beta-Sheet Protein  [PDF]
Seung-Yeon Kim
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.41003
Abstract:

Understanding the folding processes of a protein into its three-dimensional native structure only with its amino-acid sequence information is a long-standing challenge in modern science. Two- hundred independent folding simulations (starting from non-native conformations) and two- hundred independent unfolding simulations (starting from the folded native structure) are performed using the united-residue force field and Metropolis Monte Carlo algorithm for betanova (three-stranded antiparallel beta-sheet protein). From these extensive computer simulations, two representative folding pathways and two representative unfolding pathways are obtained in the reaction coordinates such as the fraction of native contacts, the radius of gyration, and the root- mean-square deviation. The folding pathways and the unfolding pathways are similar each other. The largest deviation between the folding pathways and the unfolding pathways results from the root-mean-square deviation near the folded native structure. In general, unfolding computer simulations could capture the essentials of folding simulations.

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