• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1102-1105
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• 2003

Energy distribution function for electrons in $SF_6$-Ar mixtures gas used by MCS-BEq algorithm has been analysed over the E/N range $30{\sim}300[Td]$ by a two term Boltzmann equation and by a Monte Carlo Simulation using a set of electron cross sections determined by other authors, experimentally the electron swarm parameters for 0.2(%) and 0.5(%) $SF_6$-Ar mixtures were measured by time-of-flight(TOF) method, The results show that the deduced electron drift velocities, Electrons Drift Velocities for a rang of E/N values. As a consequence, it was known that the spatial growth rates and the dielectric behaviors in $SF_6$-Ar mixtures are strongly dependent on the addition rate of $SF_6$ gas but the transport coefficients of electrons are insensitive to the addition rate of $SF_6$ gas. The results obtained from Boltzmann equation method and Monte Carlo simulation have been compared with present and previously obtained data and respective set of electron collision cross sections of the molecules.

• Proceedings of the KIEE Conference
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• 2003.07e
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• pp.75-78
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• 2003

Energy distribution function for electrons in $SF_6$-Ar mixtures gas used by MCS-BEq algorithm has been analysed over the E/N range $30\sim300$[Td] by a two term Boltzmann equation and by a Monte Carlo Simulation using a set of electron cross sections determined by other authors, experimentally the electron swarm parameters for 0.2[%] and 0.5[%] $SF_6$-Ar mixtures were measured by time-of-flight(TOF) method. The results show that the deduced electron drift velocities, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients and mean energy agree reasonably well with theoretical for a rang of E/N values. The transport coefficients for electrons in (0.2[%])$SF_6$-Ar and (0.5[%]$SF_6$ - Ar mixtures were measured by time-of-flight method, and the electron energy distribution function and the parameters of the velocity and the diffusion were determined by the variation of the collision cross-sections with energy. The results obtained from Boltzmann equation method and Monte Carlo simulation have been compared with present and previously obtained data and respective set of electron collision cross sections of the molecules.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.201-203
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• 2001

This paper describes the information for quantitative simulation of weakly ionized plasma. We must grasp the meaning of the plasma state condition to utilize engineering application and to understand materials of plasma state. In this paper, the drift velocity of electron in Xenon gas calculated for range of E/N values from 0.01~500[Td] at the temperature is $300[^{\circ}K]$ and pressure is 1[Torr], using a set of electron collision cross sections determined by the authors and the values of drift velocity of electrons are obtained for TOF, PT, SST sampling method of Backward Prolongation by two term approximation Boltzmann equation method. it has also been used to predict swarm parameter using the values of cross section as input. The result of Boltzmann equation, the drift velocity of electrons, has been compared with experimental data by L. S. Frost and A. V. Phelps for a range of E/N. The swarm parameter from the study are expected to server as a critical test of current theories of low energy scattering by atoms and molecules.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.53-53
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• 2003

Calumenin was previously identified as a high affinity Ca$\^$2+/ binding protein in mouse cardiac sarcoplasmic reticulum (SR). For the present study, a 48 kDa skeletal homologue of calumenin was identified by sucrose-density gradient of rabbit skeletal SR membranes, concanavalin A treatment, 2D-gel electrophoresis, $\^$45/Ca$\^$2+/ overlay, Stains-all staining, and MALDI-TOF analysis. We attempted to clone the skeletal calumenin by RT-PCR based on mouse cardiac and human calumenin sequences. The deduced amino acid sequence (315 residues) of the skeletal calumenin showed high identity to mouse cardiac calumenin (90％). As seen in the cardiac calumenin, the deduced sequence contains a 19 amino acid N-terminal signal sequence and a HDEF C-terminal sequence, a putative retrieval signal to ER. Also, the skeletal calumenin contains one N-glycosylation site, three PKC phosphorylation sites, eight casein kinase 2 phosphorylation sites, and 6 EF-hand domains. GST-calumenin showed a conformational change and increased mobility in the presence of Ca$\^$2+/ in SDS-PAGE. Three calumenin interacting proteins (ryanodine receptor 1, glycogen phosphorylase, and phosphofructo kinase) were identified by pull-down assay with GST-calumenin and solubilized SR. All the interactions were Ca$\^$2+/dependent. The present results suggest that calumenin plays an important role in Ca$\^$2+/ homeostasis of muscle cells.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.298-301
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• 2006

This paper describes the electron energy distribution function characteristics in $SF_6-Ar$ gas calculated for range of E/N values from $50\sim700[Td]$ by the Monte Carlo simulation(MCS) and Boltzmann equation(BE) method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained by time of flight(TOF) method. In this dissertation the results of the combined experimental and theoretical studies designed to understand and predict the spatial growth and transport coefficients for electrons in $SF_6$ and $SF_6-Ar$ mixtures have described. The ionization and attachment coefficients in pure $SF_6$ and $SF_6-Ar$ mixtures have been calculated over the range of 10$SF_6$ molecule and for Ar atom proposed by other authors. The results obtained in this work will provide valuable information on the fundamental behaviors of electrons in weakly ionized gases and the role of electron attachment in the choice of better gases and unitary gas dielectrics or electro negative components in dielectric gas mixtures.

• Mycobiology
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• v.51 no.6
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• pp.452-462
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• 2023

Opportunistic infections due to Cryptococcus neoformans and C. gattii species complexes continue to rise unabated among HIV/AIDS patients, despite improved antifungal therapies. Here, we collected a total of 20 environmental and 25 presumptive clinical cryptococcal isolates from cerebrospinal fluid (CSF) samples of 175 patients enrolled in an ongoing clinical trial Ambition 1 Project (Botswana-Harvard Partnership). Identity confirmation of the isolates was done using MALDI-TOF MS and PCR. We describe the diversity of the isolates by PCR fingerprinting and sequencing (Oxford Nanopore Technology) of the intergenic spacer region. Mating types of the isolates were determined by amplification of the MAT locus. We report an unusual prevalence of 42.1% of C. neoformans × C. deneoformans hybrids Serotype AD (n = 16), followed by 39.5% of C. neoformans Serotype A (n = 15), 5.3% of C. deneoformans, Serotype D (n = 2), 7.9% of C. gattii (n = 3), and 5.3% of C. tetragattii (n = 2) in 38 representative isolates that have been characterized. Mating type-specific PCR performed on 38 representative environmental and clinical isolates revealed that 16 (42.1%) were MATa/MAT𝛼 hybrids, 17 (44.7%) were MAT𝛼, and five (13.2%) possessed MATa mating type. We used conventional and NGS platforms to demonstrate a potential link between environmental and clinical isolates and lay a foundation to further describe mating patterns/history in Botswana.

• Investigative Magnetic Resonance Imaging
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• v.2 no.1
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• pp.96-103
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• 1998

Purpose : To assess the clinical utility of turbo contrast-enhanced magnetic resonance angiography(CE MRA) in the evaluation of the aortic arch and its major branches and to compare the image quality of CE MRA among different coils used. Materials and Methods : Turbo three-phase dynamic CE MRA encompassing aortic arch and its major branches was prospectively performed after manual bolus IV injection of contrast material in 29 patients with suspected cerebrovascular diseases at 1.0T MR unit. the raw data were obtained with 3-D FISH sequence (TR 5.4ms, TE 2.3ms, flip angle 30, slab thickness 80nm, effective slice thickness 4.0mm, matrix size $100{\times}256$, FOV 280mm). Total data acquisition time was 4. to 60 seconds. We subjectively evaluated the imge quality with three-rating scheme : "good" for unequivocal normal finding, "fair" for relatively satisfactory quality to diagnose 'normal' despite intravascular low signal, and "poor" for equivocal diagnosis or non-visualization of the origin or segment of the vessels due to low signal or artifacts which needs catheter angiography. At the level of the carotid bifurcation, it was compared with conventional 2D-TOF MRA image. Overall image quality was also compared visually and quantitatively by measuring signal-to-noise ratios (SNRs) of the ascending aorta, the innominate artery and both common carotid arteries among the three different coils used(CP body array(n=12), CP neck array(n=9), and head-and-neck(n=8). Results : Demonstration of the aortic arch and its major branches was rated as "good" in 55% (16/29) and "fair" in 34%(10/29). At the level of the carotid bifurcation, image quality of turbo CE MRA was same as or better than conventional 2D-TOF MRA in 65% (17/26). Overall image quality and SNR were significantlygreater with CP body array coil than with CP neck array or head-and-neck coil. Conclusions : Turbo CE MRA can be used as a screening exam in the evaluation of the major branches of the aortic arch from their origin to the skull base. Overall imagequality appears to be better with CP body array coil than with CP neck array coil or head-and-neck coil.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1182-1182
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• 2001

In this study, the newly constructed optical measurement system, which was mainly composed of a parametric tunable laser and a near infrared photoelectric multiplier, was introduced to clarify the optical characteristics of wood as discontinuous body with anisotropic cellular structure from the viewpoint of the time-of-flight near infrared spectroscopy (TOF-NIRS). The combined effects of the cellular structure of wood sample, the wavelength of the laser beam λ, and the detection position of transmitted light on the time resolved profiles were investigated in detail. The variation of the attenuance of peak maxima At, the time delay of peak maxima Δt and the variation of full width at half maximum Δw were strongly dependent on the feature of cellular structure of a sample and the wavelength of the laser beam. The substantial optical path length became about 30 to 35 times as long as sample thickness except the absorption band of water. Δt ${\times}$ Δw representing the light scattering condition increased exponentially with the sample thickness or the distance between the irradiation point and the end of sample. Around the λ=900-950 nm, there may be considerable light scattering in the lumen of tracheid, which is multiple specular reflection and easy to propagate along the length of wood fiber. Such tendency was remarkable for soft wood with the aggregate of thin layers of cell walls. When we apply TOF-NIRS to the cellular structural materials like wood, it is very important to give attention to the difference in the light scattering within cell wall and the multiple specular-like reflections between cell walls. We tried to express the characteristics of the time resolved profile on the basis of the optical parameters for light propagation determined by the previous studies, which were absorption coefficient K and scattering coefficient S from Kubelka-Munk theory and n from nth power cosine model of radiant intensity. The wavelength dependency of the product of K/S and n, which expressed the light-absorbing and -scattering condition and the degree of anisotropy, respectively, was similar to that of the time delay of peak maxima Δt. The variation of the time resolved profile is governed by the combination of these parameters. So, we can easily find the set of parameters for light propagation synthetically from Δt.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.167-172
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• 2004

In the human skin, vitamin C (L -ascorbic acid) that is well known as the activated materials has effects that is skin anti-aging and wrinkle repair by giving impetus to collagen biosynthesis and anti-oxidation, and that is the sun screen, a wound recovering, inhibition melanogenesis and so on. In spite of its effects, vitamin C has the defects of the skin stimulation and easily oxidized instability by water, air, heat and light. For solving their matters, many investigation is advanced and its results are synthesized the various vitamin C derivatives. And yet they have not solved the unstable property of vitamin C and were still insufficient for the comparing with the effect of the pure vitamin C itself. In this study, in order to prepare vitamin C derivative of being improved the stability and to apply vitamin C effect in the skin, we prepared new vitamin C derivative, phytosphingosine ascorbate, by using phytosphingosine, one of sphingolipids, which have a distinguished skin affinity. Phytosphingosine ascorbate can be prepared as the ionic bond between amine group (-NH$_2$) of phytosphingosine and hydroxy group (-OH) of vitamin C by way of the relatively simple reaction. So the structure and properties of the synthesized phytosphingosine ascorbate was confirmed the use of elemental analysis (C 58.3 : H 9.3 : N 2.8 : O 29.5), MALDI TOF-MS (Mw=492.58), Ultraviolet spectra (268.5nm), lH NMR, FT-IR spectra, thermal analysis (m.p=l54$^{\circ}C$), HPLC and so on. And we could confirm the anti-bacterial and anti-oxidation effects. Based on these results, we could confirm to prepare a new material that was expected of both effects of vitamin C and phytosphingosine and that is improved properties of vitamin C.

• Allergy, Asthma & Immunology Research
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• v.10 no.6
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• pp.628-647
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• 2018

Purpose: Obesity is associated with metabolic dysregulation, but the underlying metabolic signatures involving clinical and inflammatory profiles of obese asthma are largely unexplored. We aimed at identifying the metabolic signatures of obese asthma. Methods: Eligible subjects with obese (n = 11) and lean (n = 22) asthma underwent body composition and clinical assessment, sputum induction, and blood sampling. Sputum supernatant was assessed for interleukin $(IL)-1{\beta}$, -4, -5, -6, -13, and tumor necrosis factor $(TNF)-{\alpha}$, and serum was detected for leptin, adiponectin and C-reactive protein. Untargeted gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolic profiles in sputum, serum and peripheral blood monocular cells (PBMCs) were analyzed by orthogonal projections to latent structures-discriminate analysis (OPLS-DA) and pathway topology enrichment analysis. The differential metabolites were further validated by correlation analysis with body composition, and clinical and inflammatory profiles. Results: Body composition, asthma control, and the levels of $IL-1{\beta}$, -4, -13, leptin and adiponectin in obese asthmatics were significantly different from those in lean asthmatics. OPLS-DA analysis revealed 28 differential metabolites that distinguished obese from lean asthmatic subjects. The validation analysis identified 18 potential metabolic signatures (11 in sputum, 4 in serum and 2 in PBMCs) of obese asthmatics. Pathway topology enrichment analysis revealed that cyanoamino acid metabolism, caffeine metabolism, alanine, aspartate and glutamate metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, pentose phosphate pathway in sputum, and glyoxylate and dicarboxylate metabolism, glycerolipid metabolism and pentose phosphate pathway in serum are suggested to be significant pathways related to obese asthma. Conclusions: GC-TOF-MS-based metabolomics indicates obese asthma is characterized by a metabolic profile different from lean asthma. The potential metabolic signatures indicated novel immune-metabolic mechanisms in obese asthma with providing more phenotypic and therapeutic implications, which needs further replication and validation.