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Search Results: 1 - 10 of 25335 matches for " Hyang Burm Lee "
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Antimicrobial Activity of Eucosterol Oligosaccharides Isolated from Bulb of Squill (Scilla scilloides)  [PDF]
Hyang Burm Lee, Sang Myung Lee
Pharmacology & Pharmacy (PP) , 2013, DOI: 10.4236/pp.2013.41016
Abstract: Antimicrobial activity of methanol extract from bulb of Scilla scilloides as well as the purified eucosterol oligosaccharides (EOs) against bacteria, fungi and alga was evaluated in vitro using paper disc bioassay. EOs including scillascilloside E-1, E-2, E-3 and G-1 were isolated from the bulbs by methanol extraction, gel filtration on Sephadex LH-20 and preparative HPLC. The metabolites were identified by MS (HR-FAB-MS) and 1H- and 13C-NMR spectral data analyses. Methanol (MeOH) extract and purified compounds, EOs showed a selective inhibitory activity against eukaryotic cells including fungal species such as Aspergillus flavus, Candida albicans, Pyricularia oryzae and an alga such as Chlorella regulsris at the concentration of 200 μg/paper disc, but little active against bacteria. Out of four EO compounds, Scilla-scilloside E-3 revealed the highest activity. These results show that the MeOH extract and EOs from the medicinal plant, S. scilloides, may be applied as a natural fungicide or a food preservative for control of molds.
PG-2, a Potent AMP against Pathogenic Microbial Strains, from Potato (Solanum tuberosum L cv. Gogu Valley) Tubers Not Cytotoxic against Human Cells
Jin-Young Kim,Ramamourthy Gopal,Sang Young Kim,Chang Ho Seo,Hyang Burm Lee,Hyeonsook Cheong,Yoonkyung Park
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms14024349
Abstract: In an earlier study, we isolated potamin-1 (PT-1), a 5.6-kDa trypsin-chymotrypsin protease inhibitor, from the tubers of a potato strain ( Solanum tuberosum L cv. Gogu Valley). We established that PT-1 strongly inhibits pathogenic microbial strains, but not human bacterial strains, and that its sequence shows 62% homology with a serine protease inhibitor. In the present study, we isolated an antifungal and antibacterial peptide with no cytotoxicity from tubers of the same potato strain. The peptide (peptide-G2, PG-2) was isolated using salt-extraction, ultrafiltration and reverse-phase high performance liquid chromatography (RP-HPLC). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) showed the protein to have a molecular mass of 3228.5 Da, while automated Edman degradation showed the N-terminal sequence of PG-2 to be LVKDNPLDISPKQVQALCTDLVIRCMCCC-. PG-2 exhibited antimicrobial activity against Candida albicans, a human pathogenic yeast strain, and Clavibacter michiganensis subsp. michiganensis, a plant late blight strain. PG-2 also showed antibacterial activity against Staphylococcus aureus, but did not lyse human red blood cells and was thermostable. Overall, these results suggest PG-2 may be a good candidate to serve as a natural antimicrobial agent, agricultural pesticide and/or food additive.
Gender Differences in Rapid Eye Movement-Related Sleep Disordered Breathing  [PDF]
Minjung Youn, Joo Young Kwon, Kyu Sun Lee, Jung Hyun Park, Hyang Woon Lee
Health (Health) , 2015, DOI: 10.4236/health.2015.71012
Abstract: Sleep disordered breathing (SDB) is an independent risk factor for cardiovascular disease. It is known to be associated more frequently with men than women, particularly in the premenopausal age range. The goal of this study is to evaluate gender differences among Korean patients diagnosed with SBD. This study included 309 patients who visited our Sleep Clinic due to sleep-related symptoms and were diagnosed with SDB by overnight polysomnography (PSG). We analyzed age, gender, body mass index, various PSG indices including sleep stages, apnea-hypopnea index (AHI) and AHI ratio in rapid eye movement (REM) versus non-REM (NREM) sleep stages (R:N ratio). Of those 309 patients diagnosed with obstructive sleep apnea, 217 (70.2%) were men (mean age 51.05 ± 12.64 years) and 92 (29.8%) were women (mean age 64.53 ± 10.43 years). The mean AHI during total sleep time was 30.34 ± 21.17 in men and 21.47 ± 17.14 in women (P < 0.001). The AHI in NREM sleep was higher in men than in women (30.97 ± 22.39 versus 20.19 ± 18.17, P < 0.001), whereas the AHI in REM sleep was not significantly different between men and women (25.73 ± 21.61 versus 28.00 ± 21.76, P = 0.402). REM SDB with R:N ratio higher than 2.0 was more frequently observed in women than in men, 34.8% (32/92) of women, compared with 11.9% (26/217) in men (P < 0.001). Interestingly, the mean R:N ratio tended to decrease with increasing age in women, but remained relatively constant in men. The prevalence of REM SDB was higher in women than in men, and the gender difference was the most prominent in women with the age < 60 years old compared to age-matched and older men or women > 60 years old. These findings suggest the possibility of different pathophysiologic mechanisms of SDB between genders and also between NREM versus REM sleep, which can be partly explained by the influence of female sex hormones.
Comparison of the Multidetector-row Computed Tomographic Angiography Axial and Coronal Planes' Usefulness for Detecting Thoracodorsal Artery Perforators
Jong Gyu Kim,Soo Hyang Lee
Archives of Plastic Surgery , 2012, DOI: http://dx.doi.org/10.5999/aps.2012.39.4.354
Abstract: Background During the planning of a thoracodorsal artery perforator (TDAP) free flap,preoperative multidetector-row computed tomographic (MDCT) angiography is valuablefor predicting the locations of perforators. However, CT-based perforator mapping of thethoracodorsal artery is not easy because of its small diameter. Thus, we evaluated 1-mm-thickMDCT images in multiple planes to search for reliable perforators accurately.Methods Between July 2010 and October 2011, 19 consecutive patients (13 males, 6females) who underwent MDCT prior to TDAP free flap operations were enrolled in this study.Patients ranged in age from 10 to 75 years (mean, 39.3 years). MDCT images were acquired ata thickness of 1 mm in the axial, coronal, and sagittal planes.Results The thoracodorsal artery perforators were detected in all 19 cases. The reliableperforators originating from the descending branch were found in 14 cases, of which 6 hadtransverse branches. The former were well identified in the coronal view, and the latter in theaxial view. The location of the most reliable perforators on MDCT images corresponded wellwith the surgical findings.Conclusions Though MDCT has been widely used in performing the abdominal perforatorfree flap for detecting reliable perforating vessels, it is not popular in the TDAP free flap.The results of this study suggest that multiple planes of MDCT may increase the probabilityof detecting the most reliable perforators, along with decreasing the probability of missingavailable vessels.
Maximizing Reliability in WDM Networks through Lightpath Routing
Hyang-Won Lee,Kayi Lee,Eytan Modiano
Computer Science , 2013,
Abstract: We study the reliability maximization problem in WDM networks with random link failures. Reliability in these networks is defined as the probability that the logical network is connected, and it is determined by the underlying lightpath routing, network topologies and the link failure probability. By introducing the notion of lexicographical ordering for lightpath routings, we characterize precise optimization criteria for maximum reliability in the low failure probability regime. Based on the optimization criteria, we develop lightpath routing algorithms that maximize the reliability, and logical topology augmentation algorithms for further improving reliability. We also study the reliability maximization problem in the high failure probability regime.
Analysis of 809 Facial Bone Fractures in a Pediatric and Adolescent Population
Sang Hun Kim,Soo Hyang Lee,Pil Dong Cho
Archives of Plastic Surgery , 2012, DOI: http://dx.doi.org/10.5999/aps.2012.39.6.606
Abstract: Background Facial fractures are infrequent in children and adolescents and have differentclinical features from those in adults. The low incidence in children and adolescents reflectsthe flexibility and underdevelopment of their facial skeletons, as well as their more protectedenvironments. Only a few reports have reviewed such patients in Korea. The authors performeda retrospective study to analyze the characteristics of facial fractures in the Korean pediatricpopulation.Methods We conducted a retrospective review on a series of 741 patients, aged <18 years,with facial fractures who had been treated at our hospital between 2006 and 2010. Thefollowing parameters were evaluated: age, sex, cause, location and type of fractures, associatedinjuries, treatment and complications.Results A total of 741 consecutive patients met the inclusion criteria. The ratio of boys to girlswas 5.7:1. Facial fractures most commonly occurred in patients between 13 and 15 years ofage (36.3%). The most common causes of injury was violence. The nasal fracture was the mostcommon type of fracture (69%) and the blowout fracture was the second most common (20%).Associated injuries occurred in 156 patients (21%).Conclusions The incidence of pediatric facial fractures caused by violence is high in Korea.Our results show that as age increases, etiological factors and fracture patterns gradually shifttowards those found in adults. This study provides an overview of facial fractures in these agegroups that helps illustrate the trends and characteristics of the fractures and may be helpfulin further evaluation and management.
Survivable Paths in Multilayer Networks
Marzieh Parandehgheibi,Hyang-Won Lee,Eytan Modiano
Mathematics , 2013,
Abstract: We consider protection problems in multilayer networks. In single-layer networks, a pair of disjoint paths can be used to provide protection for a source-destination pair. However, this approach cannot be directly applied to layered networks where disjoint paths may not always exist. In this paper, we take a new approach which is based on finding a set of paths that may not be disjoint but together will survive any single physical link failure. First, we consider the problem of finding the minimum number of survivable paths. In particular, we focus on two versions of this problem: one where the length of a path is restricted, and the other where the number of paths sharing a fiber is restricted. We prove that in general, finding the minimum survivable path set is NP-hard, whereas both of the restricted versions of the problem can be solved in polynomial time. We formulate the problem as Integer Linear Programs (ILPs), and use these formulations to develop heuristics and approximation algorithms. Next, we consider the problem of finding a set of survivable paths that uses the minimum number of fibers. We show that this problem is NP-hard in general, and develop heuristics and approximation algorithms with provable approximation bounds. Finally, we present simulation results comparing the different algorithms.
Serum Carcinoembryonic Antigen Is Associated with Abdominal Visceral Fat Accumulation in Female Korean Nonsmokers
Jee-Yon Lee, Hyang-Kyu Lee, Duk-Chul Lee, Ji-Won Lee
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0043518
Abstract: Background Carcinoembryonic antigen (CEA) is a tumor marker overexpressed in adenocarcinoma that has proinflammatory properties. Recent studies have reported that CEA is positively associated with carotid atherosclerosis and metabolic syndrome. Because visceral obesity is a known risk factor for cardiometabolic diseases, CEA may also be associated with visceral adiposity. Therefore, we investigated the relationship between serum CEA concentration and visceral obesity in female Korean nonsmokers. Methods A total of 270 Korean female nonsmokers were enrolled during their routine health check-ups. Biomarkers of metabolic risk factors were assessed along with body composition by computed tomography. Serum CEA levels were measured by using a chemiluminescence immunoassay analyzer. Results Serum CEA levels correlated with visceral fat area, fasting glucose, and triglyceride levels after adjusting for age and BMI. The mean visceral fat area increased significantly with the increasing CEA tirtiles. In a step-wise multiple regression analysis, age (β = 0.26, p<0.01) and visceral fat area (β = 0.19, p = 0.03) were identified as explanatory variables for serum CEA level. Conclusions This study suggested that CEA may be a mediator that links metabolic disturbance and tumorigenesis in visceral obesity. Further studies are required to better understand the clinical and pathophysiological significance of our findings.
Corrrelation of the Specific Rates of Solvolysis of Ethyl Fluoroformate Using the Extended Grunwald-Winstein Equation
Mi Hye Seong,Jin Burm Kyong,Young Hoon Lee,Dennis N. Kevill
International Journal of Molecular Sciences , 2009, DOI: 10.3390/ijms10030929
Abstract: The specific rates of solvolysis of ethyl fluoroformate have been measured at 24.2 °C in 21 pure and binary solvents. These give a satisfactory correlation over the full range of solvents when the extended Grunwald-Winstein equation is applied. The sensitivities to changes in the NT solvent nucleophilicity scale and the YCl solvent ionizing power scale, and the kF/kCl values are very similar to those for solvolyses of n-octyl fluoroformate, consistent with the addition step of an addition-elimination pathway being rate-determining. For methanolysis, a solvent deuterium isotope effect of 3.10 is compatible with the incorporation of general-base catalysis into the substitution process. For five representative solvents, studies were made at several temperatures and activation parameters determined. The results are also compared with those reported earlier for ethyl chloroformate and mechanistic conclusions are drawn.
Correlation of the Rates of Solvolysis of i-Butyl Fluoroformate and a Consideration of Leaving-Group Effects
Yelin Lee,Kyoung-Ho Park,Mi Hye Seong,Jin Burm Kyong,Dennis N. Kevill
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12117806
Abstract: The specific rates of solvolysis of isobutyl fluoroformate ( 1) have been measured at 40.0 °C in 22 pure and binary solvents. These results correlated well with the extended Grunwald-Winstein (G-W) equation, which incorporated the N T solvent nucleophilicity scale and the Y Cl solvent ionizing power scale. The sensitivities ( l and m-values) to changes in solvent nucleophilicity and solvent ionizing power, and the kF/kCl values are very similar to those observed previously for solvolyses of n-octyl fluoroformate, consistent with the additional step of an addition-elimination pathway being rate-determining. The solvent deuterium isotope effect value ( kMeOH/kMeOD) for methanolysis of 1 was determined, and for solvolyses in ethanol, methanol, 80% ethanol, and 70% TFE, the values of the enthalpy and the entropy of activation for the solvolysis of 1 were also determined. The results are compared with those reported earlier for isobutyl chloroformate ( 2) and other alkyl haloformate esters and mechanistic conclusions are drawn.
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