• Journal of Life Science
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• v.6 no.2
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• pp.111-119
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• 1996

The production of interleukin-1(IL-1)and nitric oxide(NO) by cultured fibroblast cells of human nasal turbinate was revealed by biological assay respectively. The cells were incubated for various periods of time in the presence of staphyloccocal toxic shock syndrome toxin-1(TSST-1) and house dust mite(Dermatophagoides farinae, HDM), and the culture supernatants were harvested. There was a little difference in the activities of IL-1beta and the amount of NO produced by the cells when stimulated with 0.002-0.1$\mu$g/ml of TSSTO-1 and 0.02-1$\mu$g/ml of HDM. The shapes of the time course curves for the production of IL-1beta and NO by the cells were different. Groups stimulated with TSST-1 or HDM produced more IL-beta in 2 h than no exposure group(Control). A certain mixed group(TSST-1, 10ng+mite, 100 ng) continued to produce IL-1beta highly throughout the entire incubation period. The cells stimulated with TSST-1 or HDM produced more NO in 2 h and 6 h than that produced in the end of incubation(48 h). Also, the mixed groups were generally similar. There results suggest that induction of IL-1beta by a certain mixed condition(TSST-1+mite) in fibroblast cell in vivo may play a role in inflammation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.307-313
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• 2001

Iron excess is known to affect long-term iron accumulation and tissue change such as fibrosis in liver. To determine the changes of expression level of genes associated with fibrosis by short-term iron exposure, we measured liver mRNA levels by reverse transcription polymerase chain reaction (RT-PCR) in rats fed dietary carbonyl iron (3%, wt/wt) for 9 weeks. The results showed that the expression of the collagen (I, III) and transforming growth factor (TGF)-$\beta$I mRNAs was enhanced in high-dose iron treated rat, compared to normal-dose iron treated rat. An electron microscopy study revealed that excess iron caused increase of collagen fibrils in liver. The cell shapes and compositions of hepatocytes and extracellular matrix(ECM) in liver were changed by the iron-treatment. Also, necrosised hepatocytes were broadly seen in ECM. Taken together, we suggest that iron overload affects changes of collagen and TGF-$\beta$I gene expression and these changes are associated with liver fibrogenesis.

• Polymer(Korea)
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• v.34 no.4
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• pp.352-356
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• 2010

The effects of the filler shapes and contents on the coefficient of thermal expansion (CTE) for polypropylene (PP) composites which included three dimensional ellipsoids ($a_1>a_2>a_3$), as determined by two aspect ratios (${\rho}_\alpha=a_1/a_3$ and ${\rho}_\beta=a_1/a_2$) were analyzed by the theoretical approach proposed by Lee and Paul and compared with the experimental results. The shapes of fillers in the composites were various, such as spherical, fiber, disc, and ellipsoid, using barium sulfate, glass fiber, and mica. The longitudinal CTE of barium sulfate whose shape was sphere ($\rho_\alpha=\rho_\beta=1$) decreased. For the glass fiber, primary aspect ratio decreased with the filler content, and longitudinal CTE decreased as filler contents increased. Normal CTE initially increased in the lower filler content. For the mica, longitudinal and transverse CTE decreased but normal CTE increased in the lower filler content like predicted values.

• Steel and Composite Structures
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• v.30 no.6
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• pp.577-589
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• 2019

In this study, on-site testing was carried out to investigate the vibration performance of a composite steel-bar truss slab with steel girder system. Ambient vibration was performed to capture the primary vibration parameters (natural frequencies, damping ratios, and mode shapes). The composite floor possesses low frequency (< 10 Hz) and damping (< 2%). Based on experimental, theoretical, and numerical analyses on natural frequencies and mode shapes, the boundary condition of SCSC (i.e., two opposite edges simply-supported and the other two edges clamped) is deemed more reasonable for the composite floor. Walking excitations by one person (single excitation), two persons (dual excitation), and three persons (triple excitation) were considered to evaluate the vibration serviceability of the composite floor. The measured acceleration results show a satisfactory vibration perceptibility. For design convenience and safety, a crest factor ${\beta}_{rp}$ describing the ratio of peak acceleration to root-mean-square acceleration induced from the walking excitations is proposed. The comparisons of the modal parameters determined by ambient vibration and walking tests reveal the interaction effect between the human excitation and the composite floor.

• Journal of Astronomy and Space Sciences
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• v.15 no.1
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• pp.27-38
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• 1998

We discussed four different methods - the single, double and triple Gaussian fits, and the intensity weighted centroid fit - which extract rotation curves from several emis-sion lines(i.e. [OII], $H{\beta}$, [OIII], and $H{\alpha}$) of spiral galaxies. Spatial extents and the shapes of rotation curves derived through various methods applying to each emission lines of a sample galaxy UGC 11635 are all in a good agreement with one another. Linewidths of $H{\beta}$ and $H{\alpha}$ measure from rotation profiles are in a good agreement with $H{\alpha}$ linewidth of Courteau (1992). however, linewidths of [OII] seems to be much broader than $H{\alpha}$, and the profile of [OIII] does not follow the profile of $H{\alpha}$.

• Journal of Powder Materials
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• v.5 no.1
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• pp.22-27
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• 1998

The effect of the $\alpha$/$\beta$ phase fraction on the mechanical properties in silicon nitrides was investigated in part 1. In part II, we describe the role of microstructure on the mechanical properties and contact damage of silicon nitrides with coarse/equiaxed and coarse/elongated microstructures. Grain sizes and shapes were controlled by starting powder. Hertzian indentation using spherical indenter was also used to investigate contact damage behavior. Cone cracks from the spherical indentation were suppressed when the silicon nitride contains coarse and elongated grains. Coarse and elongated grains played an important role of cone crack suppression. The size of quasi-plastic zone does not depend on grain size or shape but depends on the fraction of $\alpha$/$\beta$ phase. A quasi-plastic zone was consisting of microcracks by shear stress during indentation.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.429-433
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• 2013

Silicon, carbon, and B4C powders were used as raw materials for the fabrication of porous SiC. ${\beta}$-SiC was synthesized at $1500^{\circ}C$ in an Ar atmosphere from a silicon and carbon mixture. The synthesized powders were pressed into disk shapes and then heated at $2100^{\circ}C$. ${\beta}$-SiC particles transformed to ${\alpha}$-SiC at over $1900^{\circ}C$, and rapid grain growth of ${\alpha}$-SiC subsequently occurred and a porous structure with elongated plate-type grains was formed. The mechanism of this rapid grain growth is thought to be an evaporation-condensation reaction. The mechanical properties of the fabricated porous SiC were investigated and discussed.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.1027-1032
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• 1995

To develop operation scenarios of KT-2 tokamak, 3 operation modes(OH, high ${\beta}$ and high bootstrap) deduced from zero dimensional steady-state power balance are examined with TSC(Tokamak Simulation Code) time-dependent transport .ode. Plasma profiles are evaluated self consistently during simulations and plasma shapes are maintained by feedback control on PF coil currents. Simulations show operation modes which are typical of KT-2 expected discharges are compatible with the KT-2 PF system design specifications[1].

• Carbon letters
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• v.13 no.3
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• pp.139-150
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• 2012

Poly-L-lactic acid (PLLA), PLLA/hydroxyapatite (HA), PLLA/multiwalled carbon nanotubes (MWNTs)/HA, PLLA/trifluoroethanol (TFE), PLLA/gelatin, and carbon nanofibers (CNFs)/${\beta}$-tricalcium phosphate (${\beta}$-TCP) composite membranes (scaffolds) were fabricated by electrospinning and their morphologies, and mechanical properties were characterized for use in bone tissue regeneration/guided tissue regeneration. MWNTs and HA nanoparticles were well distributed in the membranes and the degradation characteristics were improved. PLLA/MWNTs/HA membranes enhanced the adhesion and proliferation of periodontal ligament cells (PDLCs) by 30% and inhibited the adhesion of gingival epithelial cells by 30%. Osteoblast-like MG-63 cells on the randomly fiber oriented PLLA/TEF membrane showed irregular forms, while the cells exhibited shuttle-like shapes on the parallel fiber oriented membrane. Classical supersaturated simulated body fluids were modified by $CO_2$ bubbling and applied to promote the biomineralization of the PLLA/gelatin membrane; this resulted in predictions of bone bonding bioactivity of the substrates. The ${\beta}$-TCP membranes exhibit good biocompatibility, have an effect on PDLC growth comparable to that of pure CNF membrane, and can be applied as scaffolds for bone tissue regeneration.

• Journal of Korean Society of Forest Science
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• v.77 no.4
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• pp.421-428
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• 1988

The purpose of this study was to analyze the working time and the efficiency according to plot shape and plot size under the same conditions. We chose two stands which were relatively gently sloped end evenly distributed in number of trees and surveyed 198 plots, and 306 plots in each stand. 1. As to the time advantage of plot establishment method, the direct-four line establishment method was more favorable than the diagonal-line establishment method in a rectangular plot. 2. The method by Blumeleiss-$Me{\beta}$ trommel was more favorable than the method using a tape in a circular plot. 3. As to the time advantage, the circular plot was more favorable than the rectangular plot. Especially, the circular plot was twice more available than rectangular plot in small plot size, but enlargement of plot size gradually decreased time advantage of circular plot.