• YAKHAK HOEJI
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• v.54 no.2
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• pp.112-121
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• 2010

The cytotoxic activity of 33,4,5-trihydroxybenzoic acid methylester and related compounds on the growth of normal cell lines, human skin melanoma cells and human oral epithelioid cell line were evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and 2,3-bis-[2-methoxy-4-nitro-5-sulfo-phenyl]-2-H-tetrazolium-5-caboxanilide (XTT) methods. 3,4,5-Trihydroxybenzoic acid methylester decreased the cell viability of human skin melanoma cells and human oral epithelioid cells shown by the MTT method and the cell adhesion activity of human skin melanoma cells and human oral epithelioid cells shown by the XTT method. In light microscopy, 100 ${\mu}M$ 3,4,5-trihydroxybenzoic acid methylester showed the highest cytotoxic activity. These results suggest that 3,4,5-trihydroxybenzoic acid methylester has a potential anticancer activity.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.406-413
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• 2000

The friction and wear behaviors of Magnetron Sputtered MoS$_2$films were investigated by using a pin on disk type tester which was designed and manufactured for this experiment. The experiment was conducted by using silicon nitride (Si$_3$N$_4$) as a pin material and Magnetron Sputtered MoS$_2$on bearing steel (STB2) as a disk material, under operating conditions that include different surface roughness (Polishing specimen, Grinding specimen)(2types), linear sliding velocities in the range of 22, 44, 66mm/sec (3types), normal loads vary from 9.8N, 19.6N, 29.4N(3types), corresponding to contact pressures of 1.9∼2.7GPa and atmospheric conditions of high vacuum( 1.3${\times}$10$\^$-4/Pa), medium vacuum( 1.3${\times}$10$\^$-l/Pa), ambient air(10$\^$5/Pa)(3types). We investigated fracture mechanism in magnetron sputtered MoS$_2$films with Magnetron Sputtering method in each experiment.

• Tribology and Lubricants
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• v.31 no.6
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• pp.287-293
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• 2015

Laser surface texturing (LST), a surface engineering modification, has been considered as one of the new processes used to improve tribological characteristics of materials by creating artificially patterned microstructure on the contact surface of mechanical components. In LST technology, the laser is optimized to obtain or manufacture the dimples with maximum precision. The micro-dimples reduce the coefficients of friction and also improve the wear resistance of materials. This study investigates the effect of dimple density is investigated. For this purpose, a ball-on-disc type tester is used with AISI 52100 bearing steel as the test material. Discs are textured with a 5% and 10% dimple density. Experimental work is performed with normal loads of 5 N, 10 N, and 15 N under a fixed speed of 150 rpm at room temperature. The effect of the textured surface is compared to that of the untextured one. Experimental results show that the textured surface yields lower friction coefficients compared to those of untextured surfaces. Specifically, the 10% dimple density textured surface shows better friction reduction behavior than the 5% dimple density textured sample, and has an 18% improvement in friction reduction compared with the untextured samples. Microscopic observation using a scanning electron microscope (SEM) shows that the major friction mechanisms of the AISI 52100 bearing steel are adhesion, plastic deformation, and ploughing.

• Archives of Craniofacial Surgery
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• v.12 no.1
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• pp.22-27
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• 2011

Purpose: Packing the nose is a common procedure after the closed reduction of a nasal bone fracture to prevent postoperative complications, such as bleeding and adhesion formation as well as to stabilize the framework of the nasal bone. On the other hand, it is difficult for a patient to endure nasal packing because of breathing difficulties, headaches, chest discomfort, insomnia, general weakness and hypoxia. This study examined the availability of a bronchodilator to improve the decreased oxygen saturation and postoperative symptoms on nasal packing. Methods: From February, 2010 to July, 2010, a prospective randomized comparison of the incidence of a range of postoperative signs and symptoms was conducted on 60 patients, who did (n=30) and did not (n=30) undergo bronchodilator infusion (aminophylline 250 mg/10 mL + normal saline 100 mL IV qd) following nasal packing. The postoperative symptoms and oxygen saturation in the two groups were compared. Results: Patients who had infused the bronchodilator showed improved oxygen saturation. Nevertheless, there were no significant differences in the postoperative uncomfortable symptoms (dyspnea, headache, chest discomfort, insomnia, general weakness) between the two groups. Conclusion: A bronchodilator after nasal packing improves oxygen saturation by dilating the airway tract but it cannot reduce the uncomfortable symptoms caused by nasal obstruction. Overall, the bronchodilator is a useful medication for improving the level of oxygen saturation.

• Biomedical Science Letters
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• v.29 no.4
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• pp.242-248
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• 2023

Platelets are activated at the sites of vascular injury by a number of molecules, including adenosine diphosphate, collagen and thrombin. The full platelet aggregation is absolutely essential for the normal hemostasis. Glycyrrhiza glabra is a well-known medicinal herb that grows in various parts of the world and is known to have various effects such as antioxidant, anti-inflammatory, anti-atherogenic, anti-osteoporotic and skin-whitening. However, the platelet inhibitory effect of Glycyrrhiza glabra extract (GGE) has not been identified. In this study, we investigated if GGE inhibited platelet aggregation. We observed that GGE inhibited collagen-induced platelet aggregation, Ca²⁺ mobilization, and thromboxane A2 generation. In addition, GGE suppressed phosphorylation of phosphatidylinositol-3 kinase (PI3K), Akt and elevated phosphorylation of inositol 1,4,5-trisphosphate receptor (IP3R), vasodilator stimulated phosphoprotein (VASP). Taken together, GGE showed strong antiplatelet effects and may be used to block platelet-mediated cardiovascular diseases.

• Journal of the Korean Wood Science and Technology
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• v.2 no.2
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• pp.25-31
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• 1974

1. Various gluing qualities applying Resorcinol Plyophen #6000 were studied on aiming the strength relationships of laminated woods resulted by single species [poplar (Populus deltoides), larch(Larix leptolepis)], mixed species of (poplar and larch), preservatives, treated poplar the scarf joint with mixed species of poplar and larch and the scarf joint treated with preservatives. 1. 1 On the block shear and on the DVL tension test, the mean wood failure ratio showed an excellent value i.e., above 65% and the tangential strength for larch was higher than that of radial, but it was reversed for poplar as shown in Tables 1 and 2. 1. 2 The lamina treated with Na-PCP reduced slightly the strength but the limited strength allowed for manufacturing laminated wood was not influenced by treating Na-PCP as shown in Tables 3 and 4. 1. 3 The safe scarf ratio in the plane scarf joint was above 1/12 for larch and 1/6 for poplar regard less of the chemical treatment or untreatment as shown in Tables. 5, 6, 7 and 8. 2. In the normal and boiled state, the gluing quality of the laminated wood composed of single[poplar (Populus deltoides), larch (Larix leptolepis)] and double species (poplar and larch) glued with Resorcinol Plyophen #6000 were measured as follow, and also represented the delamination of the same laminated wood. 2.1 The normal block shear strength of the straight and curved laminated wood (in life size) were more than three times of the standards adhesion strength. And, the value of the boiled stock was decreased to one half of the standard shear adhesion strength, but it was more than twice the standard strength for the boiled stock. Thus, it was recognized that the water resistance of the Resorcinol Plyophen #6000 was very high as shown in Tables 9 and 10. 2. 2 The delamination ratio of the straight and curved laminated woods in respect of their composition were decraesed, in turn, in the following order i. e., larch, mixed stock (larch+poplar) and poplar. The maximum value represented by the larch was 3.5% but it was below the limited value as shown in Table 11. 3. The various strengthes i.e., compressive, bending and adhesion obtainted by the straight laminaced wood which were constructed by five plies of single and double species of lamina i. e., larch (Larix leptolepis) and poplar (Populus euramericana), glued with urea resin were shown as follows: 3. 1 If desired a higher strength of architectural laminated wood composed of poplar (P) and larch (L), the combination of the laminas should be arranged as follows, L+P+L+P+L as shown in Table 12. 3.2 The strength of laminated wood composed of laminas which included pith and knots was conside rably decreased than that of clear lamina as shown Table 13. 3.3 The shear strength of the FPL block of the straight laminated wood constructed by the same species which were glued with urea adhesives was more than twice the limited adhesion strength, thus it makes possible to use it for interior constructional stock.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.176-177
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• 2013

Surface plasmon polaritons (SPPs) have attracted the attention of scientists and engineers involved in a wide area of research, microscopy, diagnostics and sensing. SPPs are waves that propagate along the surface of a conductor, usually metals. These are essentially light waves that are trapped on the surface because of their interaction with the free electrons of conductor. In this interaction, the free electrons respond collectively by oscillating in resonance with the light wave. The resonant interaction between the surface charge oscillation and the electromagnetic field of the light constitutes the SPPs and gives rise to its unique properties. In this papers, we studied theoretical and experimental extraordinary transmittance (T) and reflectance (R) of 2 dimensional metal hole array (2D-MHA) on GaAs in consideration of the diffraction orders. The 2d-MHAs was fabricated using ultra-violet photolithography, electron-beam evaporation and standard lift-off process with pitches ranging from 1.8 to $3.2{\mu}m$ and diameter of half of pitch, and was deposited 5-nm thick layer of titanium (Ti) as an adhesion layer and 50-nm thick layer of gold (Au) on the semiinsulating GaAs substrate. We employed both the commercial software (CST Microwave Studio: Computer Simulation Technology GmbH, Darmstadt, Germany) based on a finite integration technique (FIT) and a rigorous coupled wave analysis (RCWA) to calculate transmittance and reflectance. The transmittance was measured at a normal incident, and the reflectance was measured at variable incident angle of range between $30^{\circ}{\sim}80^{\circ}$ with a Nicolet Fourier transmission infrared (FTIR) spectrometer with a KBr beam splitter and a MCT detector. For MHAs of pitch (P), the peaks ${\lambda}$ max in the normal incidence transmittance spectra can be indentified approximately from SP dispersion relation, that is frequency-dependent SP wave vector (ksp). Shown in Fig. 1 is the transmission of P=2.2 um sample at normal incidence. We attribute the observation to be a result of FTIR system may be able to collect the transmitted light with higher diffraction order than 0th order. This is confirmed by calculations: for the MHAs, diffraction efficiency in (0, 0) diffracted orders is lower than in the (${\pm}x$, ${\pm}y$) diffracted orders. To further investigate the result, we calculated the angular dependent transmission of P=2.2 um sample (Fig. 2). The incident angle varies from 30o to 70o with a 10o increment. We also found the splitting character on reflectance measurement. The splitting effect is considered a results of SPPs assisted diffraction process by oblique incidence.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.3
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• pp.609-616
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• 2006

The aim of this study was to investigate the effect of SR-HA(Stemonae Radix-herbal acupuncture) at Joksamni(ST36) on ovalbumin-induced asthma in mice. C57BL/6 mice were sensitized and challenged with OVA(ovalbumin) for 12 weeks(once a week). One of the two experimental groups was just treated with needle-prick on Joksamni(ST36) and the other group was treated with 1% concentrations of SR-HA at Joksamni(ST36) for the later 8 weeks (3times/week). The weight of lung of the mice group treated with SR-HA decreased significantly compared with those of control group, and significantly increased compared with those of normal group. The total cells of lung of the mice group treated with SR-HA decreased significantly compared with those of control group. Total leukocytes and eosinophils in BALF of the mice group treated wtih SR-HA decreased significantly compared with those of control group. Eosinophils in BALF of the mice group treated wtih SR-HA in Photomicrographs decreased significantly compared with those of control group. According to histological analysis of lung sections, adhesion of collagen in SR-HA decreased significantly compared with that of control group. The concentration of IgE, IL-4, IL-5 in BALF of the mice group treated with SR-HA decreased significantly compared with that of control group, and significantly increased compared with those of normal group. The concentration of IL-4, IL-5, IL-13 in serum of the mice group treated with SR-HA decreased significantly compared with that of control group, and significantly increased compared with those of normal group. The number of Gr-1+/CDl1b+, CO3-/CCR3+, CD4+, CD8+, CD3e+/CD69+ cells in the lungs of the mice group treated with SR-HA decreased significantly compared with those of control group. These results suggest that Stemonae Radix Herbal-acupuncture at Joksamni(ST36) in 057B146mice may be an effective part to OVA-induced asthma in C57BL/6 mice.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.197-197
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• 2016

Commercially pure titanium (CP Ti) and Ti-6Al-4V alloys have been widely used for biomedical applications. However, the use of the Ti-6Al-4V alloy in biomaterial is then a subject of controversy because aluminum ions and vanadium oxide have potential detrimental influence on the human body due to vanadium and aluminum. Hence, recent works showed that the synthesis of new Ti-based alloys for implant application involves more biocompatible metallic alloying element, such as, Nb, Hf, Zr and Mo. In particular, Nb and Hf are one of the most effective Ti ${\beta}-stabilizer$ and reducing the elastic modulus. Plasma electrolyte oxidation (PEO) is known as excellent method in the biocompatibility of biomaterial due to quickly coating time and controlled coating condition. The anodized oxide layer and diameter modulation of Ti alloys can be obtained function of improvement of cell adhesion. Manganese(Mn) plays very important roles in essential for normal growth and metabolism of skeletal tissue in vertebrates and can be detected as minor constituents in teeth and bone. Radio frequency(RF) magnetron sputtering in the various PVD methods has high deposition rates, high-purity films, extremely high adhesion of films, and excellent uniform layers for depositing a wide range of materials, including metals, alloys and ceramics like a hydroxyapatite. The aim of this study is to research the Mn coatings on the micro-pore formed Ti-29Nb-xHf alloys by RF-magnetron sputtering for dental applications. Ti-29Nb-xHf (x= 0, 3, 7 and 15wt%, mass fraction) alloys were prepared Ti-29Nb-xHf alloys of containing Hf up from 0 wt% to 15 wt% were melted by using a vacuum furnace. Ti-29Nb-xHf alloys were homogenized for 2 hr at $1050^{\circ}C$. Each alloy was anodized in solution containing typically 0.15 M calcium acetate monohydrate + 0.02 M calcium glycerophosphate at room temperature. A direct current power source was used for the process of anodization. Anodized alloys was prepared using 270V~300V anodization voltage at room. Mn coatings was produced by RF-magnetron sputtering system. RF power of 100W was applied to the target for 1h at room temperature. The microstructure, phase and composition of Mn coated oxide surface of Ti-29Nb-xHf alloys were examined by FE-SEM, EDS, and XRD.

• The Journal of Internal Korean Medicine
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• v.29 no.3
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• pp.543-553
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• 2008

Objective: The goal of this study was to determine the anti-asthma mechanism of SF on TNF-${\alpha}$ induced activation on A549 (human type II-like epithelial) cells. Using oligonucleotide microarray, we sought to establish the molecular mechanism of the protective effects of SF on A549 cells. Material & Methods : Cells were cultured in three different conditions: 1) negative control group was cultured in normal condition of DMEM, 2) positive control group was activated with TNF-${\alpha}$, IL-4. and IL-1${\beta}$, and 3) SF treated group was previously treated with 0.1${\mu}g/ml$ SF after TNF-${\alpha}$, IL-4. and IL-1 activation. Cells of positive control and SF treated groups were cultured for 30 min, 1hr, 3hr and 6hr. Results : The comparative analysis of the gene expression profile revealed that proinflammatory cytokines such as IL1F8, IL1F9, IL1R1. IL1RN, IL1RAPL1, IL8, TNFRSF4, TNFSF10c, TNFSF13, TRAF5, and TRAF7 and inflammation-related genes including MMP2, MMP11, MMP14, MMP15, MMP16, MMP19, MMP25, and MMP27 were down regulated with SF treatment. Cell adhesion molecule genes such as ITGB1, ITGBL1, selectin P ligand, selectin E, ICAM2, ICAM3, VCAM1, PECAM, FCER1G and MMP28 genes were also down-regulated in SF treated A549 cells. Conclusion : These results suggest that the anti-asthmatic effects of SF could be mediated by regulating specific genes related with cell adhesion, proinflammatory cytokine and inflammation-related genes in A549 cells.