• Title/Summary/Keyword: T. B. Lee

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Nuclear Magnetic Relaxation in Flurinated $YBa_2Cu_3O_{7-x}$

  • Lee, Cheol-Eui;White, D.;Davies, P.K.;Moon, B.M.;Sung, M.Y.;Park, J.H.;Kim, B.H.
    • Journal of Magnetics
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    • v.1 no.1
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    • pp.1-3
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    • 1996
  • The $YBa_2Cu_3O_{7-x}$ structure has been fluorinated by a gas phase exchange technique. The ${^19}F$NMR (nuclear magnetic resonance) spin-lattice relaxation rate (1/T1) measurements on a fluorinated sample gave superconducting energy gap of $2\Delta=4.6kT_c$.

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NF-${\kappa}B$ and CREB Are Involved in IL-8 Production of Human Neutrophils Induced by Trichomonas vaginalis-Derived Secretory Products

  • Nam, Young-Hee;Min, Deul-Le;Park, Soon-Jung;Kim, Kyeong-Ah;Lee, Young-Ah;Shin, Myeong-Heon
    • Parasites, Hosts and Diseases
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    • v.49 no.3
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    • pp.291-294
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    • 2011
  • Trichomonas vaginalis is a flagellated lumen-dwelling extracellular protozoan parasite that causes human trichomoniasis via sexual intercourse. Human neutrophils play a crucial role in acute tissue inflammatory responses in T. vaginalis infection. In this study, we investigated the signaling mechanism of neutrophil responses when stimulated with T. vaginalis-derived secretory products (TvSP), which were collected from $1{\times}10^7$ live trichomonads. Incubation of human neutrophils isolated from peripheral blood with TvSP induced up-regulation of IL-8 protein secretion. In addition, stimulation with TvSP induced phosphorylation of NF-${\kappa}B$ and CREB in neutrophils. Moreover, TvSP-induced IL-8 production was also significantly inhibited by pretreatment of neutrophils with $i{\kappa}B$ inhibitor or CREB inhibitor. These results suggest that transcription factors NF-${\kappa}B$ and CREB are involved in IL-8 production in human neutrophils induced by stimulation with T. vaginalis infection.

Investigation on the phonon behavior of MgB2 films via polarized Raman spectra

  • R. P. Putra;J. Y. Oh;G. H. An;H. S. Lee;B. Kang
    • Progress in Superconductivity and Cryogenics
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    • v.26 no.1
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    • pp.14-19
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    • 2024
  • In this study, we explore the anisotropy of electron-phonon coupling (EPC) constant in epitaxially grown MgB2 films on c-axis oriented Al2O3, examining its correlation with the critical temperature (Tc) and local structural disorder assessed through polarized Raman scattering. Analysis of the polarized Raman spectra reveals angle-dependent variations in the intensity of the phonon spectra. The Raman active mode originating from the boron plane, along with two additional phonon modes from the phonon density of states (PDOS) induced by lattice distortion, was distinctly observed. Persistent impurity scattering, likely attributed to oxygen diffusion, was noted at consistent frequencies across all measurement angles. The EPC values derived from the primary Raman active phonon do not significantly vary with changing observation angles, followed by that the Tc values calculated using the Allen and Dynes formula remain relatively constant across all polarization angles. Although the E2g phonon mode plays a crucial role in the EPC mechanism, the determination of Tc values in MgB2 involves not only electron-E2g coupling but also contributions from other phonon modes.

Toxin Gene Profiling of Bacillus cereus Food Isolates by PCR

  • Seong, Seon-Je;Lim, Ji-Su;Lee, Kwang-Geun;Lee, Seung-Ju;Hong, Kwang-Won
    • Applied Biological Chemistry
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    • v.51 no.4
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    • pp.263-268
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    • 2008
  • Seventy-one Bacillus cereus strains (12 references and 59 food isolates) were analyzed for the occurrence of five different enterotoxin genes (nheABC, hblCDA, entFM, cytK, and bceT) and one emetic toxin cereulide synthetase gene (ces) by PCR (polymerase chain reaction). PCR analysis revealed eight toxigenic patterns in all B. cereus strains tested; they all carried both entFM and nheABC. The presence of hblCDA, cytK, and bceT varied according to the enterotoxin-producing strains, among which hblCDA was the least frequently detected in the food-isolated strains. Only five B. cereus strains harbored ces, associated with the emetic type of food poisoning; however, these strains were devoid of hblCDA, cytK, and bceT.

Magnetic Anisotropy Energy Distribution and Magnetization of CoPt Nanoparticles Encaged in Protein Shell

  • Lee, T.H.;Suh, B.J.;Jang, Z.H.
    • Journal of Magnetics
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    • v.22 no.1
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    • pp.1-6
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    • 2017
  • Magnetic properties of CoPt nanoparticles (average size = 2.1 nm) encapsulated in synthesized protein shell have been investigated with SQUID (Superconducting Quantum Interference Device) magnetometer and analyzed by the recently developed non-equilibrium magnetization calculation by our group [T. H. Lee et al., Phys. Rev. B 90, 184411 (2014)]. Field dependence of magnetization measured at 2 K was successfully analyzed with modified Langevin function. In addition, small hysteresis loops having the coercive field of 890 Oe were observed at 2 K. Temperature dependence of magnetization has been measured with zero field cooled (ZFC) and field cooled (FC) protocol with slightly modified sequence in accordance with non-equilibrium magnetization calculation. The analysis on the M vs. T data revealed that the anisotropy energy barrier distribution is found to be very different from the log-normal distribution found in a size distribution. Zero temperature coercive field and Bloch coefficient have also been extracted from the analysis and the validity of those values is checked.

Bioavailability of Commercially Available Furosemide Tablet (시판 Furosemide 정제의 생체내 이용율)

  • Choi, Jun Shik;Lee, Jin Whan;Lee, Chong Ki;Shin, Gui Ho
    • Korean Journal of Clinical Pharmacy
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    • v.1 no.1
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    • pp.15-21
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    • 1991
  • This study was attempted to investigate the dissolution rate and bioavailability of commercially available furosemide preparations. A. B. and C. The dissolution test was conducted in an artificial gastric juice using the basket method. and furosemide (40 mg) was administered orally to 8 normal volunteers by cross-over design. The results were as follows: the AUC and dissolution rate in 100 min ($D_{100\;min}$) were higher in order of preparations. A > C > B. But the peak concentration. time to reach peak concentration $(T_{max})$, and mean dissolution time (MDT) were in order of preparations. C > A > B. There were significantly linear correlations between the AUC and the $D_{100\;min}$, and between the $T_{max}$ and the MDT. From the results of this experiment. it can be concluded that commercially available preparations bioavailability of furosemide, which may be predicted from the dissolution rate.

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A study on the damage process of fatigue crack growth using the stochastic model (확률적모델을 이용한 피로균열성장의 손상과정에 관한 연구)

  • Lee, Won Suk;Cho, Kyu Seoung;Lee, Hyun Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.10
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    • pp.130-138
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    • 1996
  • In general, the scattler is observed in fatigue test data due to the nonhomogeneity of a material. Consequently. It is necessary to use the statistical method to describe the fatigue crack growth process precisely. Bogdanoff and Kozin suggested and developed the B-model which is the probabilistic models of cumulative damage using the Markov process in order to describe the damage process. But the B-model uses only constant probability ratior(r), so it is not consistent with the actual damage process. In this study, the r-decreasing model using a monotonic decreasing function is introduced to improve the B-model. To verify the model, thest data of fatigue crack growth of A12024-T351 and A17075-T651 are used. Compared with the empirical distribution of test data, the distribution from the r-decreasing model is satisfactory and damage process is well described from the probabilistic and physical viewpoint.

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