175 results on '"B.-K. Lee"'
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2. The Red Queen Hypothesis and Improvisational Capabilities for Resilience: A Study of Korean Online Gaming Industry.
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B. K. Lee, Felix T. C. Tan, Zixiu Guo, and Seongmin Jeon
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- 2022
3. Turning Lemons into Lemonade: Designing Remote Teaching to Foster a Sense of Online Learning Community through Action Design.
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Zixiu Guo, Carmen Leong, Yawen Vivian Zhou, B. K. Lee, and Dincy Mini Monson
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- 2020
4. Towards a Theory of Technical Debt Ownership: An Exploratory Field Study.
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Hadi Ghanbari, Suchit Ahuja, B. K. Lee, and James E. Gaskin 0001
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- 2017
5. Complementarities in Platform Ecosystems: A Study of Coevolution of Made-in-Korea Digital Entertainment Phenomenon.
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B. K. Lee, Felix T. C. Tan, and Seongmin Jeon
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- 2019
6. Perioperative risk and benefit of antiplatelet therapy in patients undergoing non-cardiac surgery within 1 year after percutaneous coronary intervention with second-generation drug-eluting stents
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S Lee, C Kim, H Kim, S G Ahn, S Cho, J K Park, J Y Moon, H Won, Y Suh, J R Cho, Y H Cho, S J Oh, B K Lee, and J S Kime
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Cardiology and Cardiovascular Medicine - Abstract
Background Antiplatelet therapy (APT) in patients undergoing non-cardiac surgery (NCS) after percutaneous coronary intervention (PCI) is still on debate due to its opposite effects which are to prevent from cardiovascular events and to cause bleeding. There is no apparent consensus on how to determine perioperative APT strategy within 1 year after PCI. Therefore, we investigated the risk and benefit of APT in NCS within 1 year after PCI. Methods Patients undergoing NCS after PCI with second-generation drug-eluting stents are retrospectively included from multicenter cohort of 8 medical centers in Korea. Perioperative clinical event within 30 days after NCS was recorded. Net adverse clinical event (NACE) including all cause death, major adverse cardiac event (MACE, a composite of cardiac death, myocardial infarction, and stent thrombosis) and major bleeding were evaluated. To overcome bias, propensity score covariate adjustment was performed using logistic regression analysis to generate propensity scores for patients of both APT strategies. Results Total 1130 patients (median age 69 years, female 30.5%) undergoing NCS within 1 year after PCI were eligible in the cohort. Study population included 55.1% patients suffered from ACS and 22.5% underwent complex PCI. NCS included 45.8% intermediate-to-high risk surgery and 10.7% urgent or emergent surgery. APT was continued during NCS in 62.7% of the patients. More patients continued DAPT (48% vs. 32%, p Conclusions About two thirds of the patients were continuing APT during NCS. Our findings may support a careful consideration of APT continuation for some of the patients who are undergoing NCS within 1 year after PCI. Funding Acknowledgement Type of funding sources: None.
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- 2022
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7. Tritium Distribution in the Low-Level and Intermediate-Level Wastes of a Korean CANDU Reactor
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J. M. Park, H. J. Ahn, Y. K. Choi, T. J. Kim, B. K. Lee, S. B. Park, and Mu-Hyun Baik
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Nuclear and High Energy Physics ,CANDU reactor ,business.industry ,020209 energy ,Mechanical Engineering ,Nuclear engineering ,02 engineering and technology ,Nuclear power ,Intermediate level ,01 natural sciences ,Nuclear decommissioning ,010305 fluids & plasmas ,Coolant ,Nuclear Energy and Engineering ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,General Materials Science ,Tritium ,business ,Civil and Structural Engineering - Abstract
Korea Hydro & Nuclear Power Company, Ltd., has operated the Wolsong Tritium Removal Facility (WTRF) since 2007 to reduce tritium concentrations in the moderator and coolant of the Wolsong nuclear p...
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- 2020
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8. Nutritional and Hormonal Induction of Fatty Liver Syndrome and Effects of Dietary Lipotropic Factors in Egg-type Male Chicks
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Y. I. Choi, H. J. Ahn, B. K. Lee, S. T. Oh, B. K. An, and C. W. Kang
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Fatty Liver Syndrome ,Lipotropic Factor ,Estradiol Benzoate ,Lipogenic Enzyme ,ApoB mRNA ,Growing Chicks ,Animal culture ,SF1-1100 ,Animal biochemistry ,QP501-801 - Abstract
This experiment was conducted with male chicks to investigate the influence of hormones and nutrients on the development of fatty liver syndrome (FLS) as well as the effects of dietary lipotropic factors on hepatic fat accumulation and lipogenic enzyme gene expression. A total of two-hundred sixteen 4-wk-old Hy-Line male chicks were divided into six groups and fed an experimental diet (T1, low-energy diet with low levels of lipotropic factors; T2, high-energy diet with low levels of lipotropic factors; T3 and T5, low-energy diet with high levels of lipotropic factors; T4 and T6, high-energy diet with high levels of lipotropic factors) for six weeks. The chicks in T5 and T6 groups were treated with intramuscular injections of estradiol benzoate for three days prior to biopsy and clinical analysis of FLS. Chicks treated with estrogen had significantly greater liver weights than untreated chicks. The abdominal fat contents were increased in chicks consuming high-energy diets as compared to those consuming low-energy diets. Treatment with estrogen significantly increased the concentrations of serum cholesterol, triacylglycerol and phospholipid (p
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- 2012
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9. Parallel Computation of Solvent Accessible Surface Area of Protein Molecules.
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Edward B. Suh, B. K. Lee, Robert L. Martino, Bhagirath Narahari, and Alok N. Choudhary
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- 1993
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10. The Relative and Interactive Effects of Actual and Perceived Gambling Exposure on Gambling Behaviour
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S M, Ofori Dei, D R, Christensen, O A, Awosoga, B K, Lee, and A C, Jackson
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Surveys and Questionnaires ,Gambling ,Prevalence ,Humans ,Alberta - Abstract
Actual and perceptual measures of gambling exposure are important predictors of problem gambling. This study used Zero-Inflated Poisson regression analyses to assess the relative and interactive effects of actual and perceived exposure on problem gambling risk and severity. Data from the 2008 and 2009 Social and Economic Impacts of Gambling in Alberta surveys indicated actual exposure was significantly associated with problem gambling risk while perceived exposure was significantly associated with problem gambling severity. These associations differ for gamblers from emerging and mature areas. Further, actual and perceived exposure had significant interaction effects on problem gambling severity but not on risk. Implications from these findings suggest that the prevalence of problem gambling could be reduced by restrictions on gambling opportunities.
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- 2020
11. A Composite Measure of Gambling Exposure: Availability, Accessibility or Both?
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S M, Ofori Dei, D R, Christensen, O A, Awosoga, B K, Lee, and A C, Jackson
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Gambling ,Humans ,Regression Analysis ,Alberta - Abstract
Measures of availability and accessibility are often used separately or interchangeably to assess gambling exposure. This study examined the advantages of assessing gambling exposure using availability, accessibility, and a composite measure. Logistic and poisson regression analyses were used to determine the relative importance of these measures in predicting problem gambling using data from the 2008 and 2009 Social and Economic Impacts of Gambling in Alberta (SEIGA) surveys. The composite measure of gambling exposure predicted both the risk and severity of problem gambling better than the availability or accessibility measures alone. These results demonstrate that individual differences in problem gambling are better predicted by a composite measure of exposure.
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- 2020
12. P5660Clinical impact of polycythemia on cardiovascular outcome from the general population: a nationwide cohort study
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Tae Hoon Kim, B K Lee, Hui Nam Pak, Jae Sun Uhm, J Y Kim, M H Lee, Boyoung Joung, P S Yang, I.-S Kim, and Hee Tae Yu
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Pediatrics ,medicine.medical_specialty ,education.field_of_study ,business.industry ,Population ,medicine ,Cardiology and Cardiovascular Medicine ,education ,business ,Outcome (game theory) ,Cohort study - Abstract
Background Although adverse effect of anemia had been reported, effect of polycythemia on cardiovascular outcome from the general population had not been revealed yet. Methods We included 451,107 subjects who received national health examinations from the Korean National Health Insurance Service-based National Sample Cohort from 2009–2013. Medical records were screened from January 2002 to investigate the subjects' disease-free baseline period. They were followed until December 2013. We divided male and female subjects into four categories each based on hemoglobin level (normal, moderate to severe and mild anemia, polycythemia) to assess each outcome. Results During 1,735,964 person·years, 12,107 major adverse cardiovascular and cerebrovascular events (MACCE), 862 incident acute myocardial infarction (MI), 5,850 incident ischemic stroke, and 2,430 incident atrial fibrillation (AF) were observed. Compared to normal hemoglobin range group, polycythemia group showed higher MACCE (HR=1.23 [1.12–1.35] in male, HR=1.79 [1.20–2.67] in female, each p Conclusion Not only anemia but also polycythemia were significantly associated with higher rate of MACCE including death, incident MI, ischemic stroke, and AF among the general population.
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- 2019
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13. Expedition 382 Preliminary Report: Iceberg Alley and Subantarctic Ice and Ocean Dynamics
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Suzanne O'Connell, Victoria L Peck, Z. Du, Thomas N. Williams, Ian Bailey, B. K. Lee, Gerson Fauth, Stefanie Ann Brachfeld, Marga García, Michelle Guitard, Linda Armbrecht, Lisa Tauxe, Michael E Weber, Frida S. Hoem, X. Zheng, Marcus Gutjahr, Brendan T Reilly, J-H Hwang, Yasmina M. Martos, Shubham Tripathi, Sidney R. Hemming, Iván Hernández-Almeida, Maureen E. Raymo, Jonathan P. Warnock, Thomas A Ronge, Y Kato, Lara F. Pérez, M Lizuka, A. Glüder, and Osamu Seki
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geography ,Water mass ,geography.geographical_feature_category ,Oceanography ,Antarctic Intermediate Water ,Ice core ,Sea ice ,Antarctic ice sheet ,Glacial period ,Ice sheet ,Geology ,Iceberg - Abstract
International Ocean Discovery Program (IODP) Expedition 382, Iceberg Alley and Subantarctic Ice and Ocean Dynamics, investigated the long-term climate history of Antarctica, seeking to understand how polar ice sheets responded to changes in insolation and atmospheric CO2 in the past and how ice sheet evolution influenced global sea level and vice versa. Five sites (U1534–U1538) were drilled east of the Drake Passage: two sites at 53.2°S at the northern edge of the Scotia Sea and three sites at 57.4°–59.4°S in the southern Scotia Sea. We recovered continuously deposited late Neogene sediment to reconstruct the past history and variability in Antarctic Ice Sheet (AIS) mass loss and associated changes in oceanic and atmospheric circulation. The sites from the southern Scotia Sea (Sites U1536–U1538) will be used to study the Neogene flux of icebergs through “Iceberg Alley,” the main pathway along which icebergs calved from the margin of the AIS travel as they move equatorward into the warmer waters of the Antarctic Circumpolar Current (ACC). In particular, sediments from this area will allow us to assess the magnitude of iceberg flux during key times of AIS evolution, including the following: The middle Miocene glacial intensification of the East Antarctic Ice Sheet, The mid-Pliocene warm period, The late Pliocene glacial expansion of the West Antarctic Ice Sheet, The mid-Pleistocene transition (MPT), and The “warm interglacials” and glacial terminations of the last 800 ky. We will use the geochemical provenance of iceberg-rafted detritus and other glacially eroded material to determine regional sources of AIS mass loss. We will also address interhemispheric phasing of ice sheet growth and decay, study the distribution and history of land-based versus marine-based ice sheets around the continent over time, and explore the links between AIS variability and global sea level. By comparing north–south variations across the Scotia Sea between the Pirie Basin (Site U1538) and the Dove Basin (Sites U1536 and U1537), Expedition 382 will also deliver critical information on how climate changes in the Southern Ocean affect ocean circulation through the Drake Passage, meridional overturning in the region, water mass production, ocean–atmosphere CO2 transfer by wind-induced upwelling, sea ice variability, bottom water outflow from the Weddell Sea, Antarctic weathering inputs, and changes in oceanic and atmospheric fronts in the vicinity of the ACC. Comparing changes in dust proxy records between the Scotia Sea and Antarctic ice cores will also provide a detailed reconstruction of changes in the Southern Hemisphere westerlies on millennial and orbital timescales for the last 800 ky. Extending the ocean dust record beyond the last 800 ky will help to evaluate dust-climate couplings since the Pliocene, the potential role of dust in iron fertilization and atmospheric CO2 drawdown during glacials, and whether dust input to Antarctica played a role in the MPT. The principal scientific objective of Subantarctic Front Sites U1534 and U1535 at the northern limit of the Scotia Sea is to reconstruct and understand how ocean circulation and intermediate water formation responds to changes in climate with a special focus on the connectivity between the Atlantic and Pacific basins, the “cold water route.” The Subantarctic Front contourite drift, deposited between 400 and 2000 m water depth on the northern flank of an east–west trending trough off the Chilean continental shelf, is ideally situated to monitor millennial- to orbital-scale variability in the export of Antarctic Intermediate Water beneath the Subantarctic Front. During Expedition 382, we recovered continuously deposited sediments from this drift spanning the late Pleistocene (from ~0.78 Ma to recent) and from the late Pliocene (~3.1–2.6 Ma). These sites are expected to yield a wide array of paleoceanographic records that can be used to interpret past changes in the density structure of the Atlantic sector of the Southern Ocean, track migrations of the Subantarctic Front, and give insights into the role and evolution of the cold water route over significant climate episodes, including the following: The most recent warm interglacials of the late Pleistocene and The intensification of Northern Hemisphere glaciation.
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- 2019
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14. Comparison of benzene and toluene photodegradation under visible light irradiation by Ba-doped BiFeO3 magnetic nanoparticles with fast sonochemical synthesis
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B.-K. Lee and T. Soltani
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010302 applied physics ,Materials science ,Ferromagnetic material properties ,Band gap ,Analytical chemistry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Toluene ,chemistry.chemical_compound ,chemistry ,0103 physical sciences ,Photocatalysis ,Magnetic nanoparticles ,Physical and Theoretical Chemistry ,0210 nano-technology ,Benzene ,Photodegradation ,Visible spectrum - Abstract
Bi1-xBaxFeO3 (x = 0.02, 0.04 and 0.07) multiferroic materials with a diameter in the range of 30-40 nm were controllably synthesized by a facile ultrasonic method, with a very short reaction time of 5 min at a low temperature of 30 °C, and the resulting BiFeO3 magnetic nanoparticles (BFO MNPs) exhibited enhanced magnetic and photocatalytic performance. The substitution of Ba2+ ions for Bi3+ ions at the A-site of BFO MNPs, even at only 2%, decreased their particle size and distorted the lattice in the rhombohedral structure of BFO MNPs. Increasing the Ba doping to 7% greatly increased the ferromagnetic properties of BFO MNPs from 3.55 to 6.09 emu g-1. In comparison with pure BFO MNPs, 7% Ba substitution in the Ba-doped BFO MNP samples produced strong absorption in the visible light region, decreasing the band-gap energy from 2.11 to 1.86 eV. Photoluminescence (PL) spectroscopy identified the band-gap emission for BFO MNPs at 587 nm, while for both pure and Ba-doped samples, the other emissions were attributed to the defect states related to oxygen deficiencies inside the band gap. After 50 min of visible light irradiation, Bi1-xBaxFeO3 (x = 7%), with the lowest band gap energy, highest magnetization and smallest particle size, showed almost complete photocatalytic degradation of toluene and benzene (100 mg L-1), with 91 and 81% reduction, respectively, in total organic carbon (TOC). For all irradiation times, the mineralization efficiency of toluene was higher than that of benzene, which demonstrated that toluene is more sensitive to photocatalytic oxidation than is benzene.
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- 2017
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15. New Development and characterization of Oxide-based Selector for Cross-Point 25-nm ReRAM
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S.G. Kim, J.C. Lee, T.J. Ha, J.H. Lee, J.Y. Lee, Y.T. Park, K.W. Kim, W.K. Ju, Y.S. Ko, H.M. Hwang, B.M. Lee, J.Y. Moon, W.Y. Park, B.G. Gyun, B.-K. Lee, and J.K. Kim
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Materials science ,business.industry ,Oxide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Characterization (materials science) ,Resistive random-access memory ,chemistry.chemical_compound ,chemistry ,Optoelectronics ,Cross point ,0210 nano-technology ,business - Published
- 2018
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16. Short Communication Development of novel microsatellite markers for conservation genetic studies of Vulpes vulpes (Canidae) by using next-generation sequencing method
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K.H. Oh, J.-N. Yu, Chul-Un Chung, C.E. Lim, and B.-K. Lee
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Genetics ,education.field_of_study ,Genetic diversity ,biology ,Vulpes ,Population ,Locus (genetics) ,General Medicine ,biology.organism_classification ,Loss of heterozygosity ,Genetic structure ,Microsatellite ,Polymorphic Microsatellite Marker ,education ,Molecular Biology - Abstract
The red fox, Vulpes vulpes (Canidae), is the most widely distributed terrestrial carnivore worldwide, but this species is classified as endangered in Korea. In this study, we developed 25 polymorphic microsatellite markers that included 3-13 (mean = 6.32) alleles per locus using 22 red fox individuals. The most polymorphic locus was FR(59)TG (13 alleles) and the least polymorphic loci were FR(70)TG and FR(182)AG (3 alleles each). No significant deviation from Hardy-Weinberg equilibrium (P < 0.05) was observed for the 25 markers. Observed (HO) and expected (HE) heterozygosity varied from 0.182 to 1.000 and from 0.175 to 0.929, respectively. These newly developed microsatellite markers will be useful for investigating the genetic diversity and population genetic structure of V. vulpes and will aid in developing conservation strategies for this species.
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- 2015
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17. Observation of adhesive force and energy of adsorbents on rubber substrates by atomic force microscopy
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B. K. Lee, William Jo, Nuri Lee, and W. K. Jung
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Materials science ,Yield (engineering) ,Atomic force microscopy ,Nanotechnology ,Surfaces and Interfaces ,General Chemistry ,Surface finish ,Condensed Matter Physics ,Surfaces, Coatings and Films ,chemistry.chemical_compound ,Adsorption ,chemistry ,Natural rubber ,Sodium hypochlorite ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,Adhesive ,Composite material - Abstract
We observed the surface morphology and adhesive interaction of adsorbents on rubber substrates by atomic force microscopy (AFM). The detachment of adsorbents from rubber substrates is an important issue for various machines like home appliances and laundry machine. Since a clean surface of the functioning parts is required, a frequent cleaning process must be developed. In particular, dust and lint have a tendency to bind to the rubber surface of a laundry machine. Several practical methods have been attempted to remove these particles from the surface. Pure water, detergent, sodium hypochlorite (65 °C), and cold water (18 °C) are treated onto artificial dust and lint mixtures on rubber with water fluid by rapid rpm. The dust-and-lint adsorbents are investigated by AFM after the treatment, and topographic images and force–distance (F–D) curves were generated for the samples. The roughness, measured as the root mean square, is a key factor to judge the cleaning quality. From the F–D curves, we are able to obtain adhesive energy in addition to adhesive force which will yield qualitative measures of the interactions between the remaining adsorbents and the rubber surface. Considering the values that were measured, hot water with water fluid by rapid rpm offers the best performance when cleaning the surface. The chemical like sodium hypochlorite is good for thinning the materials, but it solidifies them, which is eventually detrimental to proper functioning. Copyright © 2014 John Wiley & Sons, Ltd.
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- 2014
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18. New method for preparation of low oxygen Mo powder by reduction of MoO3using Ca
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C.-Y. Suh, H.-S. Kim, J.-M. Oh, J.-W. Lim, B.-K. Lee, and W. Kim
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Materials science ,Low oxygen ,Reducing agent ,Inorganic chemistry ,Metals and Alloys ,chemistry.chemical_element ,Condensed Matter Physics ,Oxygen ,Reduction (complexity) ,chemistry ,Mechanics of Materials ,Molybdenum ,Materials Chemistry ,Ceramics and Composites ,Limiting oxygen concentration - Abstract
A new method for the reduction of MoO3 using Ca as a reducing agent was developed. A low oxygen Mo powder can thus be prepared by two-step reduction process: the first step reduction involves a contact type method while the second step reduction uses a non-contact type method involving Ca vapour followed by additional deoxidation. The oxygen concentration in the resultant Mo powder was ∼2800 ppm, which was much lower than that of commercial Mo powder (>4400 ppm).
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- 2014
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19. Preparation of ultrahigh purity cylindrical tantalum ingot by electron beam drip melting without sintering process
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H-S Kim, J-W Lim, B-K Lee, G-S Choi, and J-M Oh
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Materials science ,Glow Discharge Mass Spectrometry ,Mechanical Engineering ,Metallurgy ,Tantalum ,chemistry.chemical_element ,Sintering ,Raw material ,Condensed Matter Physics ,chemistry ,Mechanics of Materials ,Impurity ,Scientific method ,Cathode ray ,General Materials Science ,Ingot - Abstract
A two-step process was used to obtain an ultrahigh purity cylindrical tantalum ingot from tantalum powder. Generally, powders cannot be used as raw materials in processes employing electron beam (EB) drip melting. We designed a process that could indeed use powders. The first step reduced the impurities in tantalum by the repeated EB melting of tantalum buttons fabricated from tantalum powder. An ultrahigh purity tantalum ingot was then fabricated by repeated EB drip melting of the refined tantalum buttons. A cylindrical ingot (O80×100 mm) with purity of 99·9998% was obtained. The purity of the raw tantalum powder was 99·9944%, while those of tantalum buttons remelted twice and four times were 99·9989 and 99·9994% respectively. The concentration of gas impurities such as C, N and O was reduced to
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- 2013
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20. Optimal Safe Path For Robots.
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Tsu-Tian Lee, B. K. Lee, and T. K. Chen
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- 1988
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21. Effect of LED phototherapy on blood lactate level in Taekwondo contest
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Sang-Joon Lee, B. K. Lee, Sungkyoo Lim, and Hyeongchan Park
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Near infrared light ,business.industry ,Quadriceps muscle ,Light-Emitting Diode Therapy ,030206 dentistry ,Led phototherapy ,030207 dermatology & venereal diseases ,03 medical and health sciences ,0302 clinical medicine ,LED therapy ,Anesthesia ,Blood lactate ,Medicine ,Red light ,business - Abstract
The effect of LED phototherapy on blood lactate level in the muscle was studied. A 450cm2 large red and near infrared LED pad with its irradiance of 10mW/cm2 was applied for 10 minutes to brachial muscle and quadriceps muscle of thigh to the participants before and after the Taekwondo contest. Blood samples from the participants were taken at 5 minutes after the competition and 10 minutes after the recovery. The test results showed that the LED therapy (LEDT) before and after the competition had a significant effect on the decrease of blood lactate level of the participants.
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- 2017
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22. Comparison of benzene and toluene photodegradation under visible light irradiation by Ba-doped BiFeO
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T, Soltani and B-K, Lee
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Bi
- Published
- 2017
23. The N-terminal region of the dopamine D2 receptor, a rhodopsin-like GPCR, regulates correct integration into the plasma membrane and endocytic routes
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J H Cheong, Min-Ho Oak, K S Jung, S J Cheong, M Zheng, Kyeong-Man Kim, B K Lee, S Y Cheong, C Min, and D I Cho
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Pharmacology ,Beta-Arrestins ,Dopamine receptor D2 ,media_common.quotation_subject ,Endocytic cycle ,Enzyme-linked receptor ,5-HT5A receptor ,Biology ,Internalization ,Receptor ,G protein-coupled receptor ,media_common ,Cell biology - Abstract
BACKGROUND AND PURPOSE Functional roles of the N-terminal region of rhodopsin-like GPCR family remain unclear. Using dopamine D2 and D3 receptors as a model system, we probed the roles of the N-terminal region in the signalling, intracellular trafficking of receptor proteins, and explored the critical factors that determine the functionality of the N-terminal region. EXPERIMENTAL APPROACH The N-terminal region of the D2 receptor was gradually shortened or switched with that of the D3 receptor or a non-specific sequence (FLAG), or potential N-terminal glycosylation sites were mutated. Effects of these manipulations on surface expression, internalization, post-endocytic behaviours and signalling were determined. KEY RESULTS Shortening the N-terminal region of the D2 receptor enhanced receptor internalization and impaired surface expression and signalling; ligand binding, desensitization and down-regulation were not affected but their association with a particular microdomain, caveolae, was disrupted. Replacement of critical residues within the N-terminal region with the FLAG epitope failed to restore surface expression but partially restored the altered internalization and signalling. When the N-terminal regions were switched between D2 and D3 receptors, cell surface expression pattern of each receptor was switched. Mutations of potential N-terminal glycosylation sites inhibited surface expression but enhanced internalization of D2 receptors. CONCLUSIONS AND IMPLICATIONS Shortening of N-terminus or mutation of glycosylation sites located within the N-terminus enhanced receptor internalization but impaired the surface expression of D2 receptors. The N-terminal region of the D2 receptor, in a sequence-specific manner, controls the receptor's conformation and integration into the plasma membrane, which determine its subcellular localization, intracellular trafficking and signalling properties.
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- 2012
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24. Preparation and Purity Evaluation of 5N-Grade Ruthenium by Electron Beam Melting
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B.-K. Lee, Jae-Won Lim, Hyung-Ki Park, and Jung-Min Oh
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Materials science ,Mechanical Engineering ,Metallurgy ,chemistry.chemical_element ,Condensed Matter Physics ,Vacuum sintering ,Grain size ,Ruthenium ,chemistry ,Mechanics of Materials ,Impurity ,Cathode ray ,General Materials Science ,Metallic impurities ,Ingot - Abstract
In this study, we carried out an electron beam (EB) melting purification process to obtain a 5N-grade high-purity Ru ingot from commercial Ru powder. The first step was to primarily sinter Ru powder compact by means of vacuum heat treatment at 1,773K. Vacuum sintering was employed to ensure a high vacuum condition during EB melting by the removal of remaining gaseous elements between the compact powders. The second step was to obtain Ru ingots by EB melting of the sintered Ru compact. The purity of the Ru raw powder was 99.962mass% and the purity of a premelted Ru button ingot obtained by EB melting was 99.9873mass%. The purities of the respective Ru button ingots remelted for 2 and 4min were 99.9988 and 99.9992mass%, respectively. As a result, the sum of metallic impurities in the Ru ingot refined for 6min was 5.3massppm and the purity of the ingot considerably increased up to 99.9995mass%, which means that a 5N-grade high-purity Ru ingot can be obtained by the EB melting purification process. Furthermore, the EB-melted Ru ingot showed an excellent ability to remove interstitial impurities. [doi:10.2320/matertrans.M2012155]
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- 2012
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25. Changes in hepatic lipid parameters and hepatic messenger ribonucleic acid expression following estradiol administration in laying hens (Gallus domesticus)
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H. J. Ahn, Hoon Taek Lee, Jin Man Kim, Chang Won Kang, J. H. Hwang, Ji-Suk Kim, B. K. Lee, and Byoung-Ki An
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medicine.medical_specialty ,Apolipoprotein B ,Oviposition ,Peroxisome Proliferator-Activated Receptors ,Transaminase ,chemistry.chemical_compound ,Internal medicine ,medicine ,Animals ,RNA, Messenger ,Poultry Diseases ,Fatty liver hemorrhagic syndrome ,Estradiol ,biology ,Triglyceride transport ,Cholesterol ,Fatty liver ,Lipid metabolism ,Vitamins ,General Medicine ,Lipid Metabolism ,medicine.disease ,Fatty Liver ,Fatty acid synthase ,Endocrinology ,Liver ,chemistry ,biology.protein ,Female ,Animal Science and Zoology ,Chickens - Abstract
Fatty liver hemorrhagic syndrome (FLHS) is characterized by increased hepatic triacylglycerol content associated with liver hemorrhages and results in a sudden decline in egg production. Genetic, environmental, nutritional, and hormonal factors have all been implicated in the etiology of FLHS, but the exact cause of FLHS is still unknown. Estrogens have been implicated in the development of excess fat content of the liver and in the etiology of FLHS. This study investigated estradiol (E(2)) administration in hens and its effect on lipid metabolism. Hy-Line Brown laying hens were intramuscularly injected with E(2) on a daily basis for 3 wk. The dosages were 0, 0.5, and 1.0 mg/kg of BW, with corn oil injections used as a control. Egg production and quality were measured among the groups, with no significant difference seen in egg production. Liver weights of hens treated with E(2) were greater than those of control hens, but the increase was not statistically significant. Serum glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase activities and E(2) plasma concentrations increased in a dose-dependent manner, with plasma concentration of E(2) increasing from 6,900 to 19,000 pg/mL. No significant differences in free cholesterol or phospholipids were observed, but there was a significant increase in hepatic triacylglycerol levels. Injection with E(2) showed an increased expression of mRNA for peroxisome proliferator-activated receptor γ (23-fold), but not for peroxisome proliferator-activated receptor α. A statistically significant increase was seen for fatty acid synthase, apolipoprotein B, and adenosine triphosphate citrate lyase, but not for acetyl coenzyme A carboxylase, apolipoprotein VLDL-II, microsomal triglyceride transport protein, or malic enzyme. For proteins involved in the oxidation of E(2), only cytochrome P450 3A37 showed a statistically significant increase. The present results suggest that E(2) upregulates the synthesis of fatty acids and triacylglycerols and the accumulation of hepatic lipids by increasing mRNA expression related to lipid metabolism, and that excess E(2) in the blood leads to activation of E(2) catabolic metabolism (cytochrome P450 3A37)-related mRNA expression.
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- 2010
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26. Effect of Dietary Organic or Inorganic Minerals (Selenium and Copper) on Layer's Production and Their Transfer into the Egg
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C. W. Kang, J. Y. Kim, E. J. Kim, B. K. Lee, S. J. You, B. K. Ahn, J. M. Kim, and T. S. Park
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chemistry ,Blood cholesterol ,chemistry.chemical_element ,Food science ,Biology ,Copper ,Selenium - Abstract
Division of Animal Care, Cheonan Yonam CollegeABSTRACT This experiment was conducted using 350 Lohmann Brown layers (67 weeks of age) to evaluate the dietary effect of organic or inorganic Se and Cu on their contents in chicken eggs. The layers were divided into seven groups and fed a commercial diet or one of the six experimental diets containing different levels of Se and Cu (T1, 0.3ppm organic Se; T2, 1.0ppm organic Se; T3, 1.0ppm inorganic Se; T4, 125ppm organic Cu; T5, 250ppm organic Cu; and T6, 250ppm inorganic Cu) for 5 weeks. No significant differences were observed in egg production and its qualities among groups. The contents of blood cholesterol in the birds fed various levels of Se and Cu were not significantly different as compared to control. Se contents in eggs were linearly increased as dietary Se levels increased for both sources, but Se contents from the groups fed organic Se were slightly higher than those fed inorganic Se. Sensory characteristics of eggs were not influenced by dietary treatments. In conclusion, Se contents in eggs were linearly increased as dietary levels of organic or inorganic Se increased, but eggs in layers fed the diet containing organic Se did not show higher Se contents than those in birds fed dietary inorganic Se.(Key words : selenium, copper, laying performance, transfer, laying hens)
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- 2009
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27. Extinction of interacting nonpremixed flames and existence of stationary retreating edges in twin-jet counterflow
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Suk Ho Chung, Seung Yeon Yang, B. K. Lee, and S. K. Ryu
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Jet (fluid) ,Positive edge ,Chemistry ,business.industry ,General Chemical Engineering ,Diffusion flame ,Nozzle ,General Physics and Astronomy ,Energy Engineering and Power Technology ,General Chemistry ,Mechanics ,Edge (geometry) ,Hysteresis ,Fuel Technology ,Optics ,Extinction (optical mineralogy) ,Modeling and Simulation ,Combustor ,business - Abstract
A two-dimensional ‘twin-jet counterflow’ burner, in which two opposing streams from two double-slit nozzles form a counterflow, has been utilised to investigate the effect of the interaction of nonpremixed flames on extinction behavior. Results show that owing to the existence of unique petal-shaped flames, the extinction boundary for the cross-stream arrangement can be extended appreciably, as compared with that for the conventional counterflow arrangement, through the interaction of the curved sections of the interacting flames. The stationary petal-shaped flames had four flame edges, consisting of two retreating edges with negative edge speed in the direction toward the burnt gas region and two propagating edges with positive edge speed in the direction toward the unburned mixture. The OH-PLIF images of the petal-shaped flames demonstrated a strong concentration interaction between the two curved flame sections. Hysteresis in the transition between the petal-shaped flame and the curved flame having pla...
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- 2009
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28. Effects of Dietary Supplementation of Domestic Skullcap (Scutellaria baicalensis) Extracts on Performance, Immune Response and Intestinal Microflora in Broiler Chicken
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J. S. Kim, S. Y. Lee, B. K. Ahn, E. J. Kim, C. W. Kang, J. Y. Kim, B. K. Lee, W. S. Lee, and H. S. Kwon
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medicine.drug_class ,Antibiotics ,Broiler ,Antibody titer ,Biology ,biology.organism_classification ,Feed conversion ratio ,Microbiology ,Coliform bacteria ,Caecum ,chemistry.chemical_compound ,Animal science ,High-density lipoprotein ,chemistry ,medicine ,Scutellaria baicalensis - Abstract
This study was carried out to investigate dietary effects of extracts of Skullcap (Scutellaria baicalensis) (SCE) grown in Korea on growth performance, immune and physiological responses in broiler chickens. Total of seven-hundred fifty 1-d-old Ross male broiler chicks were divided into five groups and fed control diets (antibiotics medicated or non-medicated commercial diets) or each experimental diet (non-medicated diets containing 0.1, 0.3 or 0.5% SCE) for 5 weeks. The body weight gain and feed conversion rate in the groups fed diets containing 0.1% or 0.3% SCE were significantly improved as compared with those of non-medicated control group (P
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- 2009
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29. Resistance to fluoroquinolones by the combination of target site mutations and enhanced expression of genes for efflux pumps in Shigella flexneri and Shigella sonnei strains isolated in Korea
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B.-K. Lee, S.-M. Jeon, M.-S. Park, S.-H. Kim, Ho-Gun Rhie, and J.-Y. Kim
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DNA Topoisomerase IV ,Microbiology (medical) ,Shigella sonnei ,Microbial Sensitivity Tests ,medicine.disease_cause ,Microbiology ,Shigella flexneri ,Bacterial Proteins ,Drug Resistance, Bacterial ,medicine ,Humans ,Shigella ,heterocyclic compounds ,Norfloxacin ,Antibacterial agent ,Dysentery, Bacillary ,Korea ,biology ,Chemistry ,fluoroquinolones resistance ,General Medicine ,Gene Expression Regulation, Bacterial ,biochemical phenomena, metabolism, and nutrition ,biology.organism_classification ,bacterial infections and mycoses ,Shigella spp ,digestive system diseases ,Anti-Bacterial Agents ,Sparfloxacin ,Infectious Diseases ,DNA Gyrase ,Mutation ,bacteria ,efflux pump ,Efflux ,Ofloxacin ,medicine.drug ,Fluoroquinolones - Abstract
Among 5938 clinical Shigella spp. isolates, two S. flexneri strains were isolated as those resistant to fluoroquinolones based on the MICs of the following antibiotics: ciprofloxacin, norfloxacin, ofloxacin, sparfloxacin and levofloxacin. S. flexneri 021787 had three substitutions, one in GyrA (Ser83Leu) and two in ParC (Ser80Ile and Arg91Gln). S. flexneri 021895 had four substitutions, two in GyrA (Ser83Leu and Asp87Gly) and two in ParC (Ser80Ile and Arg91Gln). The increased susceptibility of S. flexneri 021787 and S. flexneri 021895 to ciprofloxacin, norfloxacin and ofloxacin in the presence of the uncoupler carbonyl cyamide-m-chlorophenyldrazone implied that energy-dependent active efflux pumps contributed to the resistance against fluoroquinolones. Both S. flexneri 021787 and S. flexneri 021895 were also induced to express tolC (encoding a resistance–nodulation–division transporter), mdfA (encoding a major facilitator superfamily transporter), and ydhE (encoding a multidrug and toxic compound extrusion transporter) in the presence of ciprofloxacin. Thus, these results indicated that chromosome-mediated fluoroquinolone resistance of S. flexneri 021787 and S. flexneri 021895 resulted from the combination of target site mutations and enhanced expression of genes encoding efflux pumps.
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- 2008
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30. Peroxiredoxin II promotes hepatic tumorigenesis through cooperation with Ras/Forkhead box M1 signaling pathway
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D-H Bang, D-Y Yu, B-K Lee, Y-H Park, J-M Kim, K-T Chang, I-S Song, S-U Kim, D-S Lee, Kim, S.E. Lee, T-H Kwon, and Hj Shin
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0301 basic medicine ,MAPK/ERK pathway ,Cancer Research ,Carcinoma, Hepatocellular ,Blotting, Western ,Transplantation, Heterologous ,Mice, Nude ,Mice, Transgenic ,Biology ,medicine.disease_cause ,Proto-Oncogene Proteins p21(ras) ,03 medical and health sciences ,Mice ,Cyclin D1 ,Cell Line, Tumor ,Genetics ,medicine ,Animals ,Humans ,Molecular Biology ,Cells, Cultured ,Mice, Knockout ,Gene knockdown ,Cell growth ,Kinase ,Reverse Transcriptase Polymerase Chain Reaction ,Forkhead Box Protein M1 ,Liver Neoplasms ,Hep G2 Cells ,Peroxiredoxins ,digestive system diseases ,Gene Expression Regulation, Neoplastic ,030104 developmental biology ,Cell Transformation, Neoplastic ,Liver ,Immunology ,Cancer research ,FOXM1 ,NIH 3T3 Cells ,Female ,RNA Interference ,Peroxiredoxin ,Carcinogenesis ,Peptides ,Signal Transduction - Abstract
The current study was carried out to define the involvement of Peroxiredoxin (Prx) II in progression of hepatocellular carcinoma (HCC) and the underlying molecular mechanism(s). Expression and function of Prx II in HCC was determined using H-ras(G12V)-transformed HCC cells (H-ras(G12V)-HCC cells) and the tumor livers from H-ras(G12V)-transgenic (Tg) mice and HCC patients. Prx II was upregulated in H-ras(G12V)-HCC cells and H-ras(G12V)-Tg mouse tumor livers, the expression pattern of which highly similar to that of forkhead Box M1 (FoxM1). Moreover, either knockdown of FoxM1 or site-directed mutagenesis of FoxM1-binding site of Prx II promoter significantly reduced Prx II levels in H-ras(G12V)-HCC cells, indicating FoxM1 as a direct transcription factor of Prx II in HCC. Interestingly, the null mutation of Prx II markedly decreased the number and size of tumors in H-ras(G12V)-Tg livers. Consistent with this, knockdown of Prx II in H-ras(G12V)-HCC cells reduced the expression of cyclin D1, cell proliferation, anchorage-independent growth and tumor formation in athymic nude mice, whereas overexpression of Prx II increased or aggravated the tumor phenotypes. Importantly, the expression of Prx II was correlated with that of FoxM1 in HCC patients. The activation of extracellular signal-related kinase (ERK) pathway and the expression of FoxM1 and cyclin D1 were highly dependent on Prx II in H-ras(G12V)-HCC cells and H-ras(G12V)-Tg livers. Prx II is FoxM1-dependently-expressed antioxidant in HCC and function as an enhancer of Ras(G12V) oncogenic potential in hepatic tumorigenesis through activation of ERK/FoxM1/cyclin D1 cascade.
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- 2015
31. Development of novel microsatellite markers for conservation genetic studies of Vulpes vulpes (Canidae) by using next-generation sequencing method
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J-N, Yu, C-U, Chung, K H, Oh, B-K, Lee, and C E, Lim
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Conservation of Natural Resources ,Heterozygote ,Base Sequence ,Endangered Species ,Molecular Sequence Data ,Foxes ,Genetic Variation ,High-Throughput Nucleotide Sequencing ,Sequence Analysis, DNA ,Genetics, Population ,Republic of Korea ,Animals ,Alleles ,Microsatellite Repeats - Abstract
The red fox, Vulpes vulpes (Canidae), is the most widely distributed terrestrial carnivore worldwide, but this species is classified as endangered in Korea. In this study, we developed 25 polymorphic microsatellite markers that included 3-13 (mean = 6.32) alleles per locus using 22 red fox individuals. The most polymorphic locus was FR(59)TG (13 alleles) and the least polymorphic loci were FR(70)TG and FR(182)AG (3 alleles each). No significant deviation from Hardy-Weinberg equilibrium (P0.05) was observed for the 25 markers. Observed (HO) and expected (HE) heterozygosity varied from 0.182 to 1.000 and from 0.175 to 0.929, respectively. These newly developed microsatellite markers will be useful for investigating the genetic diversity and population genetic structure of V. vulpes and will aid in developing conservation strategies for this species.
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- 2015
32. Electrical characterization of the platinum/YSZ interfaces in SOFCs via micro-contact impedance spectroscopy
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Jung-Moo Lee, Hwaung Lee, Junsun Kim, Y.-H. Yu, Sung Moon Kim, B.-K. Lee, J.-H. Hwang, and B.-S. So
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Materials science ,Contact resistance ,Analytical chemistry ,Oxide ,Electrolyte ,Condensed Matter Physics ,Capacitance ,Electronic, Optical and Magnetic Materials ,Dielectric spectroscopy ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Electrode ,Materials Chemistry ,Ceramics and Composites ,Solid oxide fuel cell ,Electrical and Electronic Engineering ,Composite material ,Yttria-stabilized zirconia - Abstract
The concept of micro-contact in electrodes was incorporated into AC two-probe impedance spectroscopy in order to clarify the electrode-related responses in solid oxide fuel cells (SOFCs). The pointed contact of one electrode was combined with the planar electrode as a counterpart in characterizing an YSZ (yttria-stabilized zirconia)/Pt interface of SOFCs. The micro-contact in electrodes induced the decrease in capacitance and the increase in impedance and amplified the bulk responses in YSZ due to the constricted electroding area. The bulk-related portions can be separated from the interfacial polarization of Pt, even though the electrolyte/electrode interface was found to be very sensitive to the measurement condition, i.e., the oscillating voltage. The resolved bulk and interfacial resistances were analyzed using a concept of “spreading resistance.’’ Furthermore, the electrode-related issues were ramified for the application of impedance spectroscopy to the solid oxide fuel cells.
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- 2006
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33. Power control for CDMA cellular radio systems via l/sub 1/ optimal predictor
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Y.-H. Chen, B.-K. Lee, and Bor-Sen Chen
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Code division multiple access ,Computer science ,Applied Mathematics ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Signal-to-interference-plus-noise ratio ,Data_CODINGANDINFORMATIONTHEORY ,Upper and lower bounds ,Noise (electronics) ,Computer Science Applications ,Tracking error ,Control theory ,Fading ,Electrical and Electronic Engineering ,Robust control ,Computer Science::Information Theory ,Power control ,Communication channel - Abstract
In direct-sequence code division multiple access (DS-CDMA) cellular radio systems, power control is an important means to achieve higher communication link quality and larger system capacity. In order to track a desired signal-to-interference-plus-noise ratio (SINR) under round-trip delay, multiple access interference (MAI), channel fading, and noise, a robust state feedback control via a desired pole (eigenvalue) placement and an l1 optimal prediction is proposed for power control of CDMA systems. The l1 predictor is used to predict the tracking error to compensate for the effect of round-trip delay, such that the peak of prediction error due to the uncertainties of channel fading, interference, and noise is as small as possible. Then the optimal l1 predictor design problem is transformed to a suboptimal prediction problem by minimizing the upper bound of the l1 norm of SINR tracking error and solving the eigenvalue problem (EVP) under some linear matrix inequality (LMI) constraints. Under the proposed framework, the global information of the channel gains of all users in the CDMA system is not required
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- 2006
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34. Modeling and Replication of Microlens Arrays Fabricated by a Modified LIGA Process
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S S Lee, T H Kwon, B K Lee, S S Yang, D S Kim, and H S Lee
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Microlens ,Materials science ,parasitic diseases ,Electroforming ,technology, industry, and agriculture ,Surface roughness ,Focal length ,Molding (process) ,Substrate (electronics) ,Replication (microscopy) ,Composite material ,LIGA - Abstract
Microlens arrays were fabricated by a modified LIGA process composed of the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, both hot embossing and microinjection molding processes have been successfully utilized with the fabricated mold insert. Replicated microlenses showed very good surface roughness with the order of 1 nm. The focal lengths of the injection molded microlenses were successfully estimated theoretically and also measured experimentally.
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- 2006
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35. Development of the Automobile Part for the Engine Oil Leakage Prevention by the Precise Cold Forging
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H B Kwon and B K Lee
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Engineering ,business.product_category ,business.industry ,Process analysis ,Mechanical engineering ,Die (manufacturing) ,Shrink-fitting ,Forming processes ,Design systems ,business ,Finite element method ,Forging ,Leakage (electronics) - Abstract
This study was aimed at the design of the dies for the automobile part for the engine oil leakage prevention using the computer simulation to shorten the period of production, on the basis of the process planning which was designed by the field experts. In the computer simulation,`eesy-2-form` of 2D FEM simulation package and `eesy-DieOpt` have been used, which are the commercial process analysis and die design program. Through the simulation of `eesy-2-form`, we could know the propriety of the forming process, the inner pressure of the die and the suitable fitting pressure between the insert and the sleeve which was not showing any positive tangential stresses in the insert. Through the simulation of `eesy-DieOpt`, we could know the number of the stress ring, the diameter ratios, the stresses of the die, the shrink fitting tolerance and temperature in the condition of the already determined maximum outer die diameter of the multi-stage former. The validity of the die design using the computer simulation was analyzed by the experiments and the results were satisfactory. As the results of this study, the new and easy die design system for cold forging has been developed.
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- 2005
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36. Characterization of new O3:K6 strains and phylogenetically related strains of Vibrio parahaemolyticus isolated in Taiwan and other countries
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T.-K. Wang, C.-S. Chiou, Hin-Chung Wong, Y.-J. Chung, Mitsuaki Nishibuchi, C.-L. Lee, Chien-Hsien Chen, B.-K. Lee, and S.-H. Liu
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Lipopolysaccharides ,Taiwan ,Virulence ,Applied Microbiology and Biotechnology ,Disease Outbreaks ,Microbiology ,Foodborne Diseases ,Lethal Dose 50 ,Mice ,Phylogenetics ,Vibrionaceae ,Pulsed-field gel electrophoresis ,Animals ,Humans ,Gene ,Phylogeny ,biology ,Vibrio parahaemolyticus ,Strain (biology) ,General Medicine ,biology.organism_classification ,Electrophoresis, Gel, Pulsed-Field ,Genetic divergence ,Genes, Bacterial ,Vibrio Infections ,Food Microbiology ,Rabbits ,Biotechnology - Abstract
Aims: We analysed the genetic divergence in the pandemic new O3:K6 and phylogenetically related (new O3:K6-like) strains and compare these two groups in terms of virulence and other biological traits. Methods and Results: A total of 160 new O3:K6, new O3:K6-like and other strains of Vibrio parahaemolyticus isolated in Taiwan and other countries were collected and their clonal relationships analysed using SfiI-pulsed-field gel electrophoresis. All of the new O3:K6 and new O3:K6-like strains were grouped in cluster I with five new patterns identified. A O6:K18 strain was identified as a new member of the new O3:K6-like strains in addition to O4:K68, O1:KUT and O1:K25 strains. All of the lipopolysaccharide preparations of the selected strains exhibited closely spaced quadruplet banding patterns with similar mobility. The two groups of strains exhibited 100% sequence identity in the internal sequences of the toxR and laf genes, and also displayed similar virulence properties as determined with a suckling mouse model. Conclusions: The new O3:K6 and new O3:K6-like strains were highly similar in virulence and in several other phenotypical and genotypical traits. Significance and Impact of the Study: This work demonstrated the spread and divergence of the pandemic and related clone of V. parahaemolyticus with similar virulence.
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- 2005
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37. A New Method of Electron Temperature Determination in Unmagnetized and Magnetized RF Plasmas without RF Compensating Circuit
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B.‐K. Lee, Y.‐S. Choi, and Kyu-Sun Chung
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Physics ,business.industry ,Capacitive sensing ,Plasma ,Condensed Matter Physics ,RF probe ,symbols.namesake ,Nuclear magnetic resonance ,Optics ,Helicon ,symbols ,Langmuir probe ,Plasma diagnostics ,Radio frequency ,Oscilloscope ,business - Abstract
Collected current versus applied voltage(I-V) curve of Langmuir probe in RF plasma is severely distorted by RF fluctuations leading to overestimation of electron temperature. RF compensation circuit has been used to obtain the undistorted I-V curve, yet it produces time-averaged one. A new and simple method is proposed to get time-resolved I-V curve by picking the synchronized RF signals with digital oscilloscope and Labview program. This technique is tested in magnetized helicon plasmas and unmagnetized capacitive coupled RF plasmas.
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- 2004
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38. Allergen-specific immunosuppression by ovalbumin fused with diphtheria toxin in mice sensitized with albumins of different origin
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Joo Young Kim, Y. S. Jang, J. E. Yoo, Chae-Seon Hong, J. Y. Ro, and B. K. Lee
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Cytotoxicity, Immunologic ,Hypersensitivity, Immediate ,Allergy ,Ovalbumin ,medicine.medical_treatment ,Immunology ,Immunoglobulin E ,medicine.disease_cause ,Mice ,Allergen ,Antigen ,Albumins ,Immune Tolerance ,medicine ,Animals ,Humans ,Immunology and Allergy ,Cytotoxic T cell ,Diphtheria Toxin ,Anaphylaxis ,Serum Albumin ,Diphtheria toxin ,B-Lymphocytes ,Mice, Inbred BALB C ,biology ,Immunotherapy ,Allergens ,respiratory system ,medicine.disease ,Immunoglobulin G ,biology.protein ,Female - Abstract
Summary Background We previously reported that ovalbumin–diphtheria toxin (OVA–DT) fusion proteineliminates mast cells bearing OVA-specific IgE and protects OVA-sensitized mice from fatalanaphylaxis induced by OVA challenge.Objective To prove thespecificityof therapeutic effect of OVA–DTto allergy induced byOVA onlyand not by other allergens such as human serum albumin (HSA), and to examine the cytotoxic effectof OVA–DT on B cells bearing OVA-specific IgE.Methods Mice were sensitized with two different antigens, OVA and HSA, and then treated withOVA–DT. The therapeutic effect of OVA–DT on the allergy response to each of allergen wasevaluated by anaphylactic test. The effect of OVA–DT on the production of allergen-specific Igisotypes of the sensitized mice and the cytotoxic effect of OVA–DT on B cells expressing OVA-specific IgE were examined.Results OVA–DT suppressed only OVA-induced allergy but not HSA-induced allergy in micesensitized with a mixture of OVAandHSA.Thesuppression was prolongedeven tothemice boostedwith the same allergen 14 days after last treatment of OVA–DT.In addition, when the sensitized mice were boosted with the same allergens 14 days after lasttreatment of OVA–DT, the mice showed to increase the production of OVA-specific IgG2a/IgG3and decreased that of OVA-specific IgE. OVA–DT targeted B cells bearing OVA-specific IgE, andkilled them by DT-mediated cytotoxicity.Conclusion The therapeutic effect of OVA–DT was specific to OVA-induced allergy and thesuppression of OVA-induced allergy was continuously shown in the mice boosted with the sameallergens. This is considered to be caused by the increase of OVA-specific IgG2a and IgG3, andbecause of the decrease of OVA-specific IgE by killing of B cells bearing OVA-specific IgE.Keywords allergen–toxin fusion protein, diphtheria toxin, immunotherapy, ovalbuminSubmitted 10 October 2003; revised 10 March 2004; accepted 1 June 2004
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- 2004
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39. Serum IgE elevation correlates with blood lead levels in battery manufacturing workers
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Yong Heo, K. D. Ahn, David A. Lawrence, and B. K. Lee
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Male ,0301 basic medicine ,Manufactured Materials ,Health, Toxicology and Mutagenesis ,medicine.medical_treatment ,010501 environmental sciences ,Toxicology ,Immunoglobulin E ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,Electric Power Supplies ,Immune system ,In vivo ,medicine ,Humans ,Industry ,Interferon gamma ,0105 earth and related environmental sciences ,030102 biochemistry & molecular biology ,biology ,General Medicine ,Lead Poisoning ,Occupational Diseases ,Cytokine ,Lead ,chemistry ,Immunology ,Toxicity ,biology.protein ,Environmental Pollutants ,Female ,Antibody ,medicine.drug ,Toxicant - Abstract
Lead (Pb), an occupational and environmental toxicant, is known to induce immunomodulatory effects resulting in lowered resistance to infectious micro-organisms and altered levels of immunoglobulins in humans. Preferential activation of type-2 helper T cells and inhibition of type-1 T-cell activation is considered a cellular mechanism for the Pb-induced immune alteration, which has not been investigated well in humans. Lead's influence on in vivo balance between type-1 and type-2 activities was assessed among workers exposed to Pb through battery manufacturing in Korea. Serum IgE levels were significantly higher in the workers with a blood Pb level (PbB) of ≤30 μg/dL than in the workers with a PbB of
- Published
- 2004
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40. Structural and optical properties of InGaN/GaN triangular‐shaped quantum wells with different emission wavelengths
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Hyung Koun Cho, R. J. Choi, H. J. Lee, H. W. Shim, C.-H. Hong, D. S. Kang, Yoon-Bong Hahn, Eun-Kyung Suh, and B. K. Lee
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Laser linewidth ,Wavelength ,Materials science ,business.industry ,Impurity ,Multiple quantum ,Optoelectronics ,business ,Misfit strain ,Emission intensity ,Intensity (heat transfer) ,Quantum well - Abstract
We investigated the structural and optical properties of InGaN/GaN triangular-shaped multiple quantum well (MQW) structures as a function of emission wavelengths. As the peak wavelength became longer, the average In composition increased linearly and the peak linewidth in the PL measurements became broad. Also, the PL intensity showed the highest value at 23% In and the interface showed the best abruptness, but the lowest intensity at 30% In. A decrease in emission intensity is ascribed to the crystalline imperfection such as defects and/or impurities caused by increased misfit strain in the QW regions with relatively higher In composition.
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- 2003
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41. Study of the origin of luminescence in high indium composition InGaN/GaN quantum wells
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Hyo-Jong Lee, Eun-Kyung Suh, M. G. Cheong, C. Liu, H. W. Choi, and B. K. Lee
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Photoluminescence ,Materials science ,Condensed matter physics ,Condensed Matter::Other ,Exciton ,Wide-bandgap semiconductor ,General Physics and Astronomy ,chemistry.chemical_element ,Biasing ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter::Materials Science ,chemistry ,Luminescence ,Quantum ,Quantum well ,Indium - Abstract
We report the emission properties of various InGaN/GaN quantum wells. The photoluminescence of InxGa1−xN/GaN (x>20%) quantum wells under varying external bias voltages has been investigated. A redshift of the photoluminescence peak position and decrease of photoluminescence peak intensity with an increase in voltage were observed regardless of the direction of external bias applied. For the sample in which the quantum dot-like region is abundant in quantum well layers, the peak position and intensity were not influenced much by the externally applied bias voltage. The results show that the origin of strong emission from InGaN/GaN quantum wells can be attributed to exciton localization in the quantum dot-like region and they are consistent with those of high-resolution transmission electron microscopy.
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- 2003
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42. Preparation method of Ti powder with oxygen concentration of <1000 ppm using Ca
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J-W Lim, C-Y Suh, B-K Lee, S-W Cho, and J-M Oh
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Materials science ,Metallurgy ,technology, industry, and agriculture ,Metals and Alloys ,food and beverages ,chemistry.chemical_element ,Condensed Matter Physics ,Preparation method ,High oxygen ,chemistry ,Mechanics of Materials ,Materials Chemistry ,Ceramics and Composites ,Melting point ,Limiting oxygen concentration ,Titanium - Abstract
To reduce the high oxygen concentration of commercial Ti powder and to obtain Ti powder with the oxygen concentration of
- Published
- 2012
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43. Deoxidation of Ti Powder and Preparation of Ti Ingot with Low Oxygen Concentration
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B.-K. Lee, J.-M. Oh, J.-W. Lim, S.-W. Cho, and Chang-Yul Suh
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Materials science ,Hydrogen ,Low oxygen ,Mechanical Engineering ,Metallurgy ,chemistry.chemical_element ,Vacuum arc ,Condensed Matter Physics ,Oxygen ,Titanium powder ,chemistry ,Mechanics of Materials ,Vickers hardness test ,General Materials Science ,Limiting oxygen concentration ,Ingot - Abstract
In this experiment, we carried out a two-step deoxidation process to obtain Ti ingots with low oxygen concentration from commercial Ti powder. The first step was to primarily reduce oxygen in Ti powder using Ca and the second was to melt the deoxidized Ti powder in Ar atmosphere with added hydrogen using a vacuum arc melting system. We used two types of raw Ti powder, one with a high oxygen concentration of 5,600ppm and average powder size of 35µm, and the other with 2,200ppm and 115µm. The high oxygen of 5,600ppm in the Ti powder was reduced to approximately 1,460ppm by the two-step process of melting after deoxidizing the Ti powder with Ca at 973K. On the other hand, in the case of the Ti powder with low oxygen of 2,200ppm, the Ti ingot with low oxygen of 600ppm could be prepared by the twostep process of melting after deoxidizing at 1,103K. The Vickers hardness and c/a value of Ti ingots decreased as the oxygen concentration decreased. [doi:10.2320/matertrans.M2012004]
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- 2012
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44. A Practical Method for N-Methylation of Indoles Using Dimethyl Carbonate
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Thomas B. K. Lee, Zhihong Chen, Xinglong Jiang, Maethonia Thompson, and Thomas P. Cleary, and Ashish Tiwari
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Indole test ,chemistry.chemical_compound ,Chemistry ,Reagent ,Organic Chemistry ,Organic chemistry ,Physical and Theoretical Chemistry ,N methylation ,Dimethyl carbonate ,Ring (chemistry) - Abstract
A new method for N-methylation of indoles using environmentally safe and less toxic methylating reagent, dimethyl carbonate (DMC), has been developed. The effect of various functional groups on the indole ring has been investigated. This method provides the desired product in high yields with high purity and is suitable for large-scale production. This process was used successfully in a 300-gal reactor train for N-methylation of 6-nitroindole.
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- 2001
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45. Probing the Binding Domain of the Saccharomyces cerevisiae α-Mating Factor Receptor with Fluorescent Ligands
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Lesley Davenport, Jeffrey M. Becker, B. K. Lee, Fa-Xiang Ding, Melinda Hauser, and Fred Naider
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Receptors, Peptide ,Stereochemistry ,Iodide ,Saccharomyces cerevisiae ,Ligands ,Binding, Competitive ,Biochemistry ,Fungal Proteins ,heterocyclic compounds ,Receptor ,Fluorescent Dyes ,chemistry.chemical_classification ,Fungal protein ,biology ,Cell Membrane ,technology, industry, and agriculture ,Biological activity ,4-Chloro-7-nitrobenzofurazan ,biology.organism_classification ,Fluorescence ,Spectrometry, Fluorescence ,chemistry ,Receptors, Mating Factor ,lipids (amino acids, peptides, and proteins) ,Mating Factor ,Peptides ,Transcription Factors ,Binding domain - Abstract
Three analogues of the alpha-mating factor pheromone of Saccharomyces cerevisiae containing the 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD) group were synthesized that had high binding affinity to the receptor and retained biological activity. The fluorescence emission maximum of the NBD group in [K7(NBD),Nle(12)]-alpha-factor was blue shifted by 35 nm compared to buffer when the pheromone bound to its receptor. Fluorescence quenching experiments revealed that the NBD group in [K7(NBD),Nle(12)]-alpha-factor bound to the receptor was shielded from collision with iodide anion when in aqueous buffer. In contrast, the emission maximum of NBD in [K7(ahNBD),Nle(12)]-alpha-factor or [Orn7(NBD),Nle(12)]-alpha-factor was not significantly shifted and iodide anion efficiently quenched the fluorescence of these derivatives when they were bound to receptor. The fluorescence investigation suggests that when the alpha-factor is bound to its receptor, K7 resides in an environment that has both hydrophobic and hydrophilic groups within a few angstroms of each other.
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- 2001
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46. Trans-resveratrol modulates the catalytic activity and mRNA expression of the procarcinogen-activating human cytochrome P450 1B1
- Author
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Thomas K. H. Chang, Hin Hin Ko, and Wendy B. K. Lee
- Subjects
Pharmacology ,chemistry.chemical_classification ,Physiology ,CYP1B1 ,Cytochrome P450 ,General Medicine ,Biology ,Resveratrol ,Molecular biology ,Enzyme assay ,body regions ,chemistry.chemical_compound ,Enzyme ,chemistry ,Biochemistry ,Cell culture ,Physiology (medical) ,Gene expression ,biology.protein ,Cytochrome P-450 Enzyme Inhibitors - Abstract
The present study was performed to determine if trans-resveratrol (3,5,4'-trihydroxy-trans-stilbene) modulates the catalytic activity and gene expression of cytochrome P450 1B1 (CYP1B1). In vitro, trans-resveratrol decreased human recombinant CYP1B1-catalyzed 7-ethoxyresorufin O-dealkylation activity, with an IC50 value of 1.4 +/- 0.2 microM (mean +/- SEM). Enzyme kinetic analysis indicated that trans-resveratrol inhibited CYP1B1 enzyme activity by a mixed-type inhibition and the apparent Ki was 0.75 +/- 0.06 microM. To determine if trans-resveratrol modulates constitutive CYP1B1 gene expression, cultured MCF-7 human breast carcinoma cells were treated with trans-resveratrol. As indicated by RT-PCR analysis, treatment of MCF-7 cells with 10 microM trans-resveratrol decreased relative CYP1B1 mRNA levels after 5 h, but not after 1.5 or 3 h, of exposure. trans-Resveratrol treatment at 5, 7.5, 10, or 20 microM for 5 h produced a concentration-dependent decrease in CYP1B1 mRNA levels. The extent of suppression was approximately 50% at 20 microM concentration. The suppressive effect was not a consequence of a toxic response to the compound as assessed by a cell proliferation assay. Overall, our novel finding that trans-resveratrol inhibits the catalytic activity and suppresses the constitutive gene expression of CYP1B1 leads to the possibility that this nutraceutical confers protection against toxicity and carcinogenicity induced by compounds that undergo CYP1B1-catalyzed bioactivation.
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- 2000
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47. Einfluss des Metabolischen Syndroms auf das Ergebnis der Karpaltunnelspaltung
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B K Lee, Y H Roh, and J H Noh
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- 2015
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48. Vergleich zwischen Plattenosteosynthese und Fixateur externe
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B K Lee, Y H Roh, and J R Baek
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- 2015
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49. Epidemiology of eating disordered symptoms in the Korean general population using a Korean version of the Eating Attitudes Test
- Author
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Young Ho Lee, M. K. Rhee, S. H. Park, C. H. Sohn, Y. C. Chung, S. K. Hong, B. K. Lee, P. Chang, A. R. Yoon, and M. Oliosi
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Adult ,Cross-Cultural Comparison ,Male ,medicine.medical_specialty ,Personality Inventory ,Psychometrics ,Cross-sectional study ,Population ,Feeding and Eating Disorders ,Risk Factors ,Epidemiology ,medicine ,Humans ,education ,Psychiatry ,education.field_of_study ,Korea ,Incidence ,Incidence (epidemiology) ,digestive, oral, and skin physiology ,Reproducibility of Results ,Middle Aged ,medicine.disease ,Cross-cultural studies ,Psychiatry and Mental health ,Clinical Psychology ,Eating disorders ,Cross-Sectional Studies ,Eating Attitudes Test ,Female ,Psychology ,Clinical psychology - Abstract
Objective: The purposes of the present study were to estimate the proportion of subjects with a high score on the Korean version of Eating Attitudes Test-26 (KEAT-26), which may provide preliminary data regarding the prevalence rate of eating disorders in the Korean general population, and to further examine the sociocultural hypothesis of eating disorders. Method: Using a multi-stage questionnaire sampling method, we surveyed 3062 subjects (1249 males, 1813 females) from 3896 Korean adults in a nationwide area. Results: 8.5% (260/3062) of subjects scored above the cut-off on the KEAT-26. Their demographic correlates, eating traits, and other characteristics relating to general psychopathology were similar to those of patients with eating disorders and female Caucasian controls in Western countries. Discussion: These results suggest that changes in various sociocultural aspects have increased the risk of developing eating disorders in Korea, and support the sociocultural hypothesis of eating disorders.
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- 1998
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50. Automatic control for DO and pH in the activated sludge process in a coke wastewater treatment plant
- Author
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J. K. Koo, H. D. Chun, S. W. Sung, and B. K. Lee
- Subjects
Environmental Engineering ,Water Science and Technology - Abstract
The objective of this study is to develop an automatic control system for dissolved oxygen (DO) and pH of the activated sludge process in a coke wastewater treatment plant. A discrete type autotuned proportional-integral (PI) controller using an auto-regressive exogenous (ARX) model as a process model was developed to maintain the DO concentration in aerators by controlling the speed of surface aerators. Also a nonlinear pH controller using the titration curve was used to control the pH of influent wastewater. This control system was tested in a pilot scale plant. During this pilot plant experiment, there was small deviation of pH and the electric power consumption of surface aerators was reduced up to 70% with respect to the full operation when the DO set point was 2 mg/l. For real plant operation with this system, the discrete PI controller showed good tracking for set point change. The electricity saving was more than 40% of the electricity consumption when considering surface aerators. As a result of maintaining the DO constantly at the set point by the automatic control system, the fluctuation of effluent quality was decreased and overall improvement of the effluent water quality was achieved.
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- 1998
- Full Text
- View/download PDF
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