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Search Results: 1 - 10 of 2195 matches for " Il Gyo Koo "
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Bacterial Inactivation of Wound Infection in a Human Skin Model by Liquid-Phase Discharge Plasma
Paul Y. Kim, Yoon-Sun Kim, Il Gyo Koo, Jae Chul Jung, Gon Jun Kim, Myeong Yeol Choi, Zengqi Yu, George J. Collins
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024104
Abstract: Background We investigate disinfection of a reconstructed human skin model contaminated with biofilm-formative Staphylococcus aureus employing plasma discharge in liquid. Principal Findings We observed statistically significant 3.83-log10 (p<0.001) and 1.59-log10 (p<0.05) decreases in colony forming units of adherent S. aureus bacteria and 24 h S. aureus biofilm culture with plasma treatment. Plasma treatment was associated with minimal changes in histological morphology and tissue viability determined by means of MTT assay. Spectral analysis of the plasma discharge indicated the presence of highly reactive atomic oxygen radicals (777 nm and 844 nm) and OH bands in the UV region. The contribution of these and other plasma-generated agents and physical conditions to the reduction in bacterial load are discussed. Conclusions These findings demonstrate the potential of liquid plasma treatment as a potential adjunct therapy for chronic wounds.
CO J=1-0 and J=2-1 Line Observations of the Molecular Cloud - Blocked Supernova Remnant 3C434.1
Il-Gyo Jeong,Bon-Chul Koo,Wan-Kee Cho,Carsten Kramer,Jürgen Stutzki,Do-Young Byun
Physics , 2013, DOI: 10.1088/0004-637X/770/2/105
Abstract: We present the results of CO emission line observations toward the semicircular Galactic supernova remnant (SNR) 3C434.1 (G94.0+1.0). We mapped an area covering the whole SNR in the 12CO J=1-0 emission line using the Seoul Radio Astronomy Observatory (SRAO) 6-m telescope, and found a large molecular cloud superposed on the faint western part of the SNR. The cloud was elongated along the north-south direction and showed a very good spatial correlation with the radio features of the SNR. We carried out 12CO J=2-1 line observations of this cloud using the K\"{o}lner Observatorium f\"{u}r Sub-Millimeter Astronomie (KOSMA) 3-m telescope and found a region in which the 12CO J=2-1 to J=1-0 ratio was high (~ 1.6). This higher excitation, together with the morphological relation, strongly suggested that the molecular cloud was interacting with the SNR. The systemic velocity of the molecular cloud (-13 km/s) gave a kinematic distance of 3.0 kpc to the SNR-molecular cloud system. We derived the physical parameters of the SNR based on this new distance. We examined the variation of the radio spectral index over the remnant and found that it was flatter in the western part, wherein the SNR was interacting with the molecular cloud. We therefore propose that 3C434.1 is the remnant of a supernova explosion that occurred just outside the boundary of a relatively thin, sheetlike molecular cloud. We present a hydrodynamic model showing that its asymmetric radio morphology can result from its interaction with this blocking molecular cloud.
Molecular environment and thermal X-ray spectroscopy of the semicircular young composite supernova remnant 3C 396
Yang Su,Yang Chen,Ji Yang,Bon-Chul Koo,Xin Zhou,Deng-Rong Lu,Il-Gyo Jeong,Tracey DeLaney
Physics , 2010, DOI: 10.1088/0004-637X/727/1/43
Abstract: We have investigated the molecular environment of the semicircular composite supernova remnant (SNR) 3C396 and performed a Chandra spatially resolved thermal X-ray spectroscopic study of this young SNR. With our CO millimeter observations, we find that the molecular clouds (MCs) at V(LSR)~84km/s can better explain the multiwavelength properties of the remnant than the V(LSR)=67-72km/s MCs that are suggested by Lee et al. (2009). At around 84km/s, the western boundary of the SNR is perfectly confined by the western molecular wall. The CO emission fades out from west to east, indicating that the eastern region is of low gas density. In particular, an intruding finger/pillar-like MC, which may be shocked at the tip, can well explain the X-ray and radio enhancement in the southwest and some infrared filaments there. The SNR-MC interaction is also favored by the relatively elevated 12CO J=2-1/J=1-0 line ratios in the southwestern "pillar tip" and the molecular patch on the northwestern boundary. The redshifted 12CO (J=1-0 and J=2-1) wings (86-90km/s) of an eastern 81km/s molecular patch may be the kinematic evidence for shock-MC interaction. We suggest that the 69km/s MCs are in the foreground based on HI self-absorption while the 84km/s MCs at a distance of 6.2 kpc (the tangent point) are in physical contact with SNR 3C396. The X-ray spectral analysis suggests an SNR age of ~3kyr. The metal enrichment of the X-ray emitting gas in the north and south implies a 13-15Msun B1-B2 progenitor star.
SRAO CO Observation of 11 Supernova Remnants in l = 70 to 190 deg
Il-Gyo Jeong,Do-Young Byun,Bon-Chul Koo,Jea-Joon Lee,Jung-Won Lee,Hyunwoo Kang
Physics , 2012, DOI: 10.1007/s10509-012-1196-1
Abstract: We present the results of 12CO J = 1-0 line observations of eleven Galactic supernova remnants (SNRs) obtained using the Seoul Radio Astronomy Observatory (SRAO) 6-m radio telescope. The observation was made as a part of the SRAO CO survey of SNRs between l = 70 and 190 deg, which is intended to identify SNRs interacting with molecular clouds. The mapping areas for the individual SNRs are determined to cover their full extent in the radio continuum. We used halfbeam grid spacing (60") for 9 SNRs and full-beam grid spacing (120") for the rest. We detected CO emission towards most of the remnants. In six SNRs, molecular clouds showed a good spatial relation with their radio morphology, although no direct evidence for the interaction was detected. Two SNRs are particularly interesting: G85.4+0.7, where there is a filamentary molecular cloud along the radio shell, and 3C434.1, where a large molecular cloud appears to block the western half of the remnant. We briefly summarize the results obtained for individual SNRs.
Fabrication of a Micro-Fluid Gathering Tool for the Gastrointestinal Juice Sampling Function of a Versatile Capsular Endoscope
Kyo-in Koo,Sangmin Lee,Dong-il Dan Cho
Sensors , 2011, DOI: 10.3390/s110706978
Abstract: This paper presents a micro-fluid gathering tool for a versatile capsular endoscope that employs a solid chemical propellant, azobisisobutyronitrile (AIBN). The proposed tool consists of a micro-heater, an AIBN matrix, a Venturi tube, a reservoir, an inlet, and an outlet. The micro-heater heats the AIBN matrix to be decomposed into by-products and nitrogen gas. This nitrogen gas generates negative pressure passing through the Venturi tube. The generated negative pressure inhales a target fluid from around the inlet into the reservoir. All the parts are designed to be embedded inside a cylindrical shape with a diameter of 17 mm and a height of 2.3 mm in order to integrate it into a versatile developmental capsular endoscope without any scaledown. Two sets of the proposed tools are fabricated and tested: one is made of polydimethylsiloxane (PDMS) and the other is made of polymethylmethacrylate (PMMA). In performance comparisons, the PDMS gathering tool can withstand a stronger pulling force, and the PMMA gathering tool requires a less negative pressure for inhaling the same target fluid. Due to the instant and full activation of the thin AIBN matrix, both types of gathering tool show analogous performance in the sample gathering evaluation. The gathered volume is approximately 1.57 μL using approximately 25.4 μL of AIBN compound.
AKARI Near-infrared Spectral Observations of Shocked H2 Gas of the Supernova Remnant IC 443
Jong-Ho Shinn,Bon-Chul Koo,Kwang-Il Seon,Ho-Gyu Lee
Physics , 2011, DOI: 10.1088/0004-637X/732/2/124
Abstract: We present near-infrared (2.5 - 5.0 um) spectra of shocked H2 gas in the supernova remnant IC 443, obtained with the satellite AKARI. Three shocked clumps-known as B, C, and G-and one background region were observed, and only H2 emission lines were detected. Except the clump B, the extinctioncorrected level population shows the ortho-to-para ratio of ~ 3.0. From the level population of the clumps C and G-both AKARI's only and the one extended with previous mid-infrared observations-we found that the v = 0 levels are more populated than the v > 0 levels at a fixed level energy, which cannot be reproduced by any combination of H2 gas in Local Thermodynamic Equilibrium. The populations are described by the two-density power-law thermal admixture model, revised to include the collisions with H atoms. We attributed the lower (n(H2)=10^(2.8-3.8) cm-3) and higher (n(H2)=10^(5.4-5.8) cm-3) density gases to the shocked H2 gas behind C-type and J-type shocks, respectively, based on several arguments including the obtained high H I abundance n(H I)/n(H2)=0.01. Under the hierarchical picture of molecular clouds, the C-type and J-type shocks likely propagate into "clumps" and "clouds" (interclump media), respectively. The power-law index b of 1.6 and 3.5, mainly determined by the lower density gas, is attributed to the shock-velocity diversity, which may be a natural result during shock-cloud interactions. According to our results, H2 v = 1 - 0 S(1) emission is mainly from J-shocks propagating into interclump media. The H2 emission was also detected at the background region, and this diffuse H2 emission may originate from collisional process in addition to the ultraviolet photon pumping.
Transovarial Transmission of Orientia tsutsugamushi in Leptotrombidium palpale (Acari: Trombiculidae)
Eun Hee Shin, Jong Yul Roh, Won Il Park, Bong Gu Song, Kyu-Sik Chang, Wook-Gyo Lee, Hee Il Lee, Chan Park, Mi-Yeoun Park, E-Hyun Shin
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088453
Abstract: Transovarial transmission of Orientia tsutsugamushi in colonies of Leptotrombidium palpale was studied in the parent and F1 and F2 generations. Both transovarial transmission and filial infection rates were 100% in the parent and F1 generations of Leptotrombidium palpale. The filial infection rate in the F1 generation was 100%, but it declined to 94.3% in the F2 progeny. The sex ratio of the F1 generation from infected L. palpale was 1:0.8 (male:female) and the proportion of males was relatively high. This study is the first to report on the transovarial transmission of O. tsutsugamushi in L. palpale. High transovarial transmission rates in L. palpale suggest that this species might be one of the major vectors of tsutsugamushi disease in Korea.
Superbridge index of composite knots
Gyo Taek Jin
Mathematics , 2000,
Abstract: An upper bound of the superbridge index of the connected sum of two knots is given in terms of the braid index of the summands. Using this upper bound and minimal polygonal presentations, we give an upper bound in terms of the superbridge index and the bridge index of the summands when they are torus knots. In contrast to the fact that the difference between the sum of bridge indices of two knots and the bridge index of their connected sum is always one, the corresponding difference for the superbridge index can be arbitrarily large.
Survival in Primary Carcinoma of the External and Middle Ear Is Strongly Dependent on Stage at Diagnosi  [PDF]
Toru Ugumori, Jun Hyodo, Naohito Hato, Kiyofumi Gyo
International Journal of Otolaryngology and Head & Neck Surgery (IJOHNS) , 2013, DOI: 10.4236/ijohns.2013.26046
Abstract: Conclusion: Early-stage detection of temporal bone carcinoma improves the survival rate. When detected at an advanced stage, predicted prognosis is poor even with a combination of surgery, radiotherapy and chemotherapy. Objectives: We evaluated treatment strategies and survival rates in cases of carcinomas of the external and middle ear. Method: Retrospective review of patients treated at Ehime University Hospital during the 32 years from 1977 to 2008. Subjects were 41 patients, consisting of 21 men and 20 women with a mean age of 63.2 years. Modified Pittsburgh staging system: stage I in 11 cases (27%), stage II in 4 (10%), stage III in 6 (15%) and stage IV in 20 (49%). Histopathology: squamous cell carcinoma (SCC) in 35 cases, adenoid cystic carcinoma (ACC) in 3, and adenocarcinoma (AC) in 3. Thirty-eight patients were treated by surgery. Radiation was added postoperatively in 23 patients. Three patients were treated by chemoradiotherapy. Results: The survival rate of carcinomas detected at an advanced stage was poor with a disease-specific 5-year survival rate of 100% in early-stage disease (stage I and II) versus 20.8% in stage III and 27.5% in stage IV disease, irrespective of histopathology of the tumor.
Internet of Things: Services and Applications Categorization  [PDF]
Matthew Gigli, Simon Koo
Advances in Internet of Things (AIT) , 2011, DOI: 10.4236/ait.2011.12004
Abstract: In this paper we attempt to categorize the services provided by the Internet of Things (IoT) in order to help application developers build upon a base service. First we introduce the four main categories of services, and then follow by providing a number of examples of each of the service categories so as to provide an example of how each type of service might be implemented, and how it can be used to build an IoT application.
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