• Korean Journal of Crystallography
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• v.8 no.2
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• pp.127-131
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• 1997

The crystal structure of a bromine sorption complex of vacuum-dehydrated Ag+ and Ca2+ exchanged zeolite A(a=12,234(1) Å) has been determined by single-crystal X-ray diffraction methods in the cubic space group Pm3m. The crystal was prepared by flow method using exchange solution in which mole ratio of AgNo3 and Ca(NO3)2 was 1:150 with a total concentration of 0.05M. The crystal was dehydrated at 360℃ and 2 ×10-6 Torr for 2days, followed by exposure to 180 Torr of Br2 vapor for 20min. full-matrix least-squares refinements converged to the final error indices of R1=0.111 and R2=0.101 using 90 reflections for which I>3o(I). About 3.1 Ag+ ions and 4.45 Ca2+ ions lie on the two crystallographically nonequivalent three-fold axes associated with 6-ring oxygens. A total of six bromine molecules are sorbed per unit cell. Each bromine molecule approaches a framework oxide ions axially (Br-Br-O=171(2)', O-Br=3.25(6) Å; and Br-Br=2,61(8) Å by a charge-transfer interaction.

• Ocean Systems Engineering
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• v.6 no.1
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• pp.23-60
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• 2016

The major objective of this study was to develop further understanding of 3D nearshore hydrodynamics under a variety of wave and tidal forcing conditions. The main tool used was a comprehensive 3D numerical model - combining the flow module of Delft3D with the WAVE solver of XBeach - of nearshore hydro- and morphodynamics that can simulate flow, sediment transport, and morphological evolution. Surf-swash zone hydrodynamics were modeled using the 3D Navier-Stokes equations, combined with various turbulence models (${\kappa}-{\varepsilon}$, ${\kappa}-L$, ATM and H-LES). Sediment transport and resulting foreshore profile changes were approximated using different sediment transport relations that consider both bed- and suspended-load transport of non-cohesive sediments. The numerical set-up was tested against field data, with good agreement found. Different numerical experiments under a range of bed characteristics and incident wave and tidal conditions were run to test the model's capability to reproduce 3D flow, wave propagation, sediment transport and morphodynamics in the nearshore at the field scale. The results were interpreted according to existing understanding of surf and swash zone processes. Our numerical experiments confirm that the angle between the crest line of the approaching wave and the shoreline defines the direction and strength of the longshore current, while the longshore current velocity varies across the nearshore zone. The model simulates the undertow, hydraulic cell and rip-current patterns generated by radiation stresses and longshore variability in wave heights. Numerical results show that a non-uniform seabed is crucial for generation of rip currents in the nearshore (when bed slope is uniform, rips are not generated). Increasing the wave height increases the peaks of eddy viscosity and TKE (turbulent kinetic energy), while increasing the tidal amplitude reduces these peaks. Wave and tide interaction has most striking effects on the foreshore profile with the formation of the intertidal bar. High values of eddy viscosity, TKE and wave set-up are spread offshore for coarser grain sizes. Beach profile steepness modifies the nearshore circulation pattern, significantly enhancing the vertical component of the flow. The local recirculation within the longshore current in the inshore region causes a transient offshore shift and strengthening of the longshore current. Overall, the analysis shows that, with reasonable hypotheses, it is possible to simulate the nearshore hydrodynamics subjected to oceanic forcing, consistent with existing understanding of this area. Part II of this work presents 3D nearshore morphodynamics induced by the tides and waves.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.634-639
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• 2013

The use of medical imaging has been increased for diagnosis of cancer or vessel disease. Among the medical imaging, computed tomography (CT) is one of the popular methods, however, which should need administration of contrast medium. Therefore, we developed gold coated liposomes (GCL) as a contrast medium. To coat gold on the liposomal surface, positive charged liposomes was prepared and then negative $Au^-$ can coat on the liposomal surface by electronic interaction. The size of GCL was $154.8{\pm}9.2$ nm and surface charge was $27{\pm}3.2$ mV, respectively. The morphology of GCL was confirmed by electron microscopy (SEM) and transmission electron microscopy (TEM). The coating efficiency of gold was 18%. Chemical procedure for gold coating on liposomal surface was not toxic for cell cytotoxicity by MTT assay. Finally, we demonstrated attractive CT image for GCL. Taken together, the GCL would be useful for various vessel related disease as a contrast medium.

• Journal of the Korean Chemical Society
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• v.32 no.3
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• pp.171-178
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• 1988

The potential energy of adsorbate molecules in the main channel of $K^+$ ion exchanged zeolite L(K-L) was calculated. In K-L which adsorbs three molecules per unit cell, the interaction energies of $H_2O,\;NH_3,\;CH_3NH_2,\;(CH_3)_2NH,\;and\;(CH_3)_3N$ molecules with zeolite lattice are 61.11, 62.31, 65.68, 74.65, and 79.88kJ/mol, respectively. These values are less by 3.7∼12.6kJ/mol than $K^+$ ion affinities with adsorbing molecules. These results may be due to the facts that the electrostatic energies are reduced by the negative charge of the lattice oxygens. The distribution of adsorption sites of $NH_3$ and $CH_3NH_2$ in K-L was investigated by a technique of temperature programmed desorption. The experimental value of desorption energies of $NH_3$ and $CH_3NH_2$ on K-L are in good agreement with the theoritical values. It is concluded that the desorption of $NH_3$ and $CH_3NH_2$ on K-L is the first-order desorption with free readsorption.

• Molecules and Cells
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• v.39 no.6
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• pp.468-476
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• 2016

PLZF-expressing invariant natural killer T cells and CD4 T cells are unique subsets of innate T cells. Both are selected via thymocyte-thymocyte interaction, and they contribute to the generation of activated/memory-like CD4 and CD8 T cells in the thymus via the production of IL-4. Here, we investigated whether $PLZF^+$ innate T cells also affect the development and function of $Foxp3^+$ regulatory CD4 T cells. Flow cytometry analysis of the thymus and spleen from both CIITA transgenic C57BL/6 and wild-type BALB/c mice, which have abundant $PLZF^+$ CD4 T cells and invariant natural killer T cells, respectively, revealed that $Foxp3^+$ T cells in these mice exhibited a $CD103^+$ activated/memorylike phenotype. The frequency of $CD103^+$ regulatory T cells was considerably decreased in $PLZF^+$ cell-deficient $CIITA^{Tg}Plzf^{lu/lu}$ and $BALB/c.CD1d^{-/-}$ mice as well as in an IL-4-deficient background, such as in $CIITA^{Tg}IL-4^{-/-}$ and $BALB/c.IL-4^{-/-}$ mice, indicating that the acquisition of an activated/ memory-like phenotype was dependent on $PLZF^+$ innate T cells and IL-4. Using fetal thymic organ culture, we further demonstrated that IL-4 in concert with TGF-${\beta}$ enhanced the acquisition of the activated/memory-like phenotype of regulatory T cells. In functional aspects, the activated/ memory-like phenotype of Treg cells was directly related to their suppressive function; regulatory T cells of $CIITA^{Tg}PIV^{-/-}$ mice more efficiently suppressed ovalbumin-induced allergic airway inflammation compared with their counterparts from wild-type mice. All of these findings suggest that $PLZF^+$ innate T cells also augmented the generation of activated/memory-like regulation via IL-4 production.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.1
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• pp.39-50
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• 2003

This study aims to figure out water quality impacts due to sudden disturbances of sediments during dike construction in land reclamation for the northern part of the Siwhaho Lake where heavily deteriorated settlements from upstream loadings are outstanding. We exploit a 3-D water quality model CE-QUAL-ICM combined with a hydrodynamic model TIDE3D. Simulations are done accounting water-sediment interaction in a 4-$\sigma$ layers. Long-term simulation for 1-year shows that bottom layers around the disturbance location are only affected and marks very high concentration. Complete vertical mixing appears at least 5km apart to downward due to complex effects of geometry, bathymetry and river inflows. It should be addressed that existing condition of the Siwhaho Lake stands for high concentration of COD and TP in winter and spring due to relatively high incoming loadings, however the effect of sediment disturbances yields reverse phenomena, i.e., impacts of dike construction arise greatly in summer and fall. Refined grid system consisting of 150m${\times}$150m rectangular grid, which is doubled system compared to previous study (Suh et al.,2002), gives affordable results by reducing flux differences through a cell especially in front of gate.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.469-472
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• 2010

Purpose: Aplasia Cutis Congenita (ACC) is a rare disease characterized by the focal defect of the skin at birth, frequently involving scalp, but it may affect any region of the body. There are no etiology known but some conditions such as intrauterine vascular ischemia, amniotic adherences and viral infections are associated. The ideal treatment for the ACC is not known. Superficial and relatively small sized defects (< $3{\times}5\;cm$) may heal spontaneously and large defects related with risks of infection and bleeding may require aggressive surgical treatment. Hyalomatrix$^{(R)}$ is a bilayer of an esterified hyaluronan scaffold beneath a silicone membrane. It has been used as a temporary dermal substitute to cover deep thickness skin defect and has physiological functions derive from the structural role in extracellular matrix and interaction with cell surface receptor. This material has been used for the wound bed pre-treatment for skin graft to follow and especially in uncooperative patient, like a newborn, this could be a efficient and aseptic way of promoting granulation without daily irritative wound care. For this reason, using Hyalomatrix$^{(R)}$ for the treatment of ACC was preferred in this paper. Methods: We report a case of a newborn with ACC of the vertex scalp and non-ossified partial skull defect. The large sized skin and skull defect ($6{\times}6\;cm$) was found with intact dura mater. No other complications such as bleeding or abnormal neurologic sign were accompanied. Escharectomy was performed and Hyalomatrix$^{(R)}$ was applied for the protection and the induction of acute wound healing for 3 months before the split-thickness skin graft. During the 3 months period, the dressing was renewed in aseptic technique for every 3 weeks. The skin graft was achieved on the healthy granulation bed. Results: The operative procedure was uneventful without necessity of blood transfusion. Postoperative physical examination revealed no additional abnormalities. Regular wound management was performed in out-patient clinic and the grafted skin was taken completely. No other problems developed during follow-up. Conclusion: Hyalomatrix$^{(R)}$ provides protective and favorable environment for wound healing. The combination of the use of Hyalomatrix$^{(R)}$ and the skin graft will be a good alternative for the ACC patients with relatively large defect on vertex.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.44-45
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• 2010

We are currently conducting studies on culturing and biocompatibility assessment of various cells such as neural stem cells and induced pluripotent stem cells(IPS cells) on carbon nanotube (CNT), on nerve regeneration electrodes, and on silicon wafers with a focus on developing nerve integrated CNT based bio devices for interfacing with living organisms, in order to develop brain-machine interfaces (BMI). In addition, we are carried out the chemical modification of carbon nanotube (mainly SWCNTs)-based bio-nanosensors by the plasma ion irradiation (plasma activation) method, and provide a characteristic evaluation of a bio-nanosensor using bovine serum albumin (BSA)/anti-BSA binding and oligonucleotide hybridization. On the other hand, the researches in the case of "novel plasma" have been widely conducted in the fields of chemistry, solid physics, and nanomaterial science. From the above-mentioned background, we are conducting basic experiments on direct irradiation of body tissues and cells using a micro-spot atmospheric pressure plasma source. The device is a coaxial structure having a tungsten wire installed inside a glass capillary, and a grounded ring electrode wrapped on the outside. The conditions of plasma generation are as follows: applied voltage: 5-9 kV, frequency: 1-3 kHz, helium (He) gas flow: 1-1.5 L/min, and plasma irradiation time: 1-300 sec. The experiment was conducted by preparing a culture medium containing mouse fibroblasts (NIH3T3) on a culture dish. A culture dish irradiated with plasma was introduced into a $CO_2$-incubator. The small animals used in the experiment involving plasma irradiation into living tissue were rat, rabbit, and pick and are deeply anesthetized with the gas anesthesia. According to the dependency of cell numbers against the plasma irradiation time, when only He gas was flowed, the growth of cells was inhibited as the floatation of cells caused by gas agitation inside the culture was promoted. On the other hand, there was no floatation of cells and healthy growth was observed when plasma was irradiated. Furthermore, in an experiment testing the effects of plasma irradiation on rats that were artificially given burn wounds, no evidence of electric shock injuries was found in the irradiated areas. In fact, the observed evidence of healing and improvements of the burn wounds suggested the presence of healing effects due to the growth factors in the tissues. Therefore, it appears that the interaction due to ion/radicalcollisions causes a substantial effect on the proliferation of growth factors such as epidermal growth factor (EGF), nerve growth factor (NGF), and transforming growth factor (TGF) that are present in the cells.

• Journal of Life Science
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• v.26 no.7
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• pp.789-795
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• 2016

A lymph node (LN) is one of the secondary lymphoid organs. An LN consists of a complicated 3 dimensional frame structure and several stromal cells. Fibroblastic reticular cells (FRC) are distributed in the T zone for interaction with T cells. FRC secrete homing chemokines such as CCL19 and CCL21. Moreover, FRC play a pivotal role in the production of extracellular matrix (ECM) into LN for ECM reorganization against pathogen infections. However, not much is known about the involvement of the immune reaction of FRC. The present report is for the characterization of FRC on immune response. For this, FRC were positioned in several infected situations such as co-culture with macrophage, lipopolysaccharide (LPS), and TNFα stimulation. When a co-culture between FRC and macrophage was performed, a morphological change in FRC was observed, and empty space between FRCs was created by this change. The soluble ICAM-1 protein level was up-regulated by co-culturing with Raw264.7 and the treatment of the ROCK inhibitor Y27632. The activity of matrix metalloproteinase (MMP) was up-regulated by LPS onto FRC. Furthermore, the inflammatory cytokine TNFα regulated the expression of ECM in FRC by a gene chip assay. Collectively, it suggests that FRC are involved in immune reactions.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.110-116
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• 2013

This study was carried out to establish the simple mass-screening methods for resistant tomato to Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL). Root dip inoculation method has been used in many studies on the resistance of tomato to disease. On the other hand, in mass-screening for resistant tomato to Fusarium wilt, the inoculation method is time-consuming and laborious procedure. Disease development of two FOL isolates on two cultivars of tomato according to inoculation method including root dip, tip and scalpel methods were investigated. In compatible interaction, tomato seedlings of each cultivar inoculated by tip method showed the lower and more variable disease severities than by root dip method. Whereas the seedlings by scalpel method represented clear resistant and susceptible responses to Fusarium wilt as root dip method. The resistance degree of each cultivar inoculated with FOL isolates by scalpel method was hardly affected by the tested incubation temperature and inoculum concentration. On the basis of the results, we suggest scalpel inoculation method as an efficient mass-screening method for resistant of tomato cultivars to Fusarium wilt. Roots of tomato seedlings at two-leaf stage grown in plastic cell tray were injured with scalpel and then spore suspension (more than $1{\times}10^7\;conidia{\cdot}mL^{-1}$) of FOL was poured directly on the roots. The infected plants were cultivated in a growth room at $25-30^{\circ}C$ for 4 weeks with 12-hours light a day.