• The Korea Journal of Herbology
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• v.21 no.4
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• pp.85-92
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• 2006

Objectives : To evaluate the neuroprotective effects of added Bo-Yang-Hwan-Oh-Tang (BHT), we investigated the neuronal death protection effects to oxidative damages in SH-SY5Y neuronal cells. Methods : To study the cytotoxic effects of BHT on SH-SY5Y cells, the cell viability was determined by MTT assay. To investigate the neuronal death protection of BHT, SH-SY5Y cells were induced oxidative damages by $H_2O_2$ and then assayed the cell viability and DNA fragmentation. We also investigated DPPH free radical scavenging effect of BHT by tube test. Results : In MTT assay, $1000{\mu}g/ml$ of BHT was not showed the cytotoxic effect on SH-SY5Y cells. BHT protected SHSY5Y cells from $H_2O_2-induced $ neuronal cell death in a dose-dependent manner. BHT also protected SH-SY5Y cells from $H_2O_2-induced$ DNA fragmentation. BHT effectively scavenged DPPH free radicals in a dose-dependent manner. Conclusion : These data suggest that BHT may have strong antioxidant effects through the free radical scavenging and neuroprotective effects in human neuronal cells.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.28-31
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• 1999

Carbon fiber/epoxy composites using electrodeposited monomeric and polymeric coupling agents were compared with the dipping and the untreated cases. Treating conditions such as time, concentration and temperature were optimized. Four-fibers embedded micro-composites were prepared for fragmentation test. Interfacial properties of four-fiber composites with different surface treatments were investigated with simultaneous acoustic emission (AE) monitoring. The microfailure mechanisms occurring from fiber break, matrix and interlayer crackings were examined by AE parameters and an optical microscope. It was found that interfacial shear strength (IFSS) of electrodeposited carbon fibers was much higher than the other cases under dry and wet conditions. Well separated and different-shaped AE groups occurs for the untreated and ED treated case, respectively.

• Toxicological Research
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• v.19 no.4
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• pp.293-296
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• 2003

The effect of the hexane extract of Curcuma zedoaria roots and its solvent fractions were investigated on the proliferation of SiHa, SNU-1 and HepG2 cell lines. Among those fractions, final fraction H2-3-1 and H2-3-3 showed cytotoxic effect on SiHa and HepG2 cell lines. The hallmark of apoptosis, DNA fragmentation, also appeared in the final fractions H2-3-1 and H2-3-3 after 24h treatment in SiHa cell line. Furthermore, those fractions were shown to be able to induce cell death in $[^3H]$thymidine incorporation test. These two fractions, H2-3-1 and H2-3-3 were determined as (-)-$\alpha$-curcumene and $\beta$-tumerone respectively by NMR and mass spectrum. From these results, it is speculated that te hexane extract of Curcuma zedoaria is necessary for further studies as a potent inhibitor of the growth of cancer cells.

• Geomechanics and Engineering
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• v.15 no.3
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• pp.811-822
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• 2018

Chip size distribution can be used to evaluate the cutting efficiency and to characterize the cutting behavior of rock during cutting and fragmentation process. In this study, a series of linear cutting tests was performed to investigate the effect of cutting conditions (specifically cut spacing and penetration depth) on the production and size distribution of rock chips. Linyi sandstone from China was used in the linear cutting tests. After each run of linear cutting machine test, the rock chips were collected and their size distribution was analyzed using a sieving test and image processing. Image processing can rapidly and cost-effectively provide useful information of size distribution. Rosin-Rammer distribution pamameters, the coarseness index and the coefficients of uniformity and curvature were determined by image processing for different cutting conditions. The size of the rock chips was greatest at the optimum cut spacing, and the size distribution parameters were highly correlated with cutter forces and specific energy.

• Sleep Medicine and Psychophysiology
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• v.15 no.2
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• pp.82-86
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• 2008

Objectives: Obstructive sleep apnea syndrome (OSAS) not only causes respiratory disturbances during sleep but also decreases the quality of nocturnal sleep through sleep fragmentation and sleep structure change. We aimed at comparing the changes in sleep fragmentation and structure between baseline (diagnostic) nocturnal polysomnography (NPSG) and nCPAP (nasal continuous positive airway pressure) titration trial. Methods: One hundred and three patients with a baseline night of respiratory disturbance index (RDI) of 5 or greater and reduced RDI score during nCPAP titration night were retrospectively selected for the study. Sleep fragementation and sleep structure between baseline NPSG and the NPSG during nCPAP titration were compared. Sleep fragmentation index (SFI) was defined as the total number of awakenings and shifts to stage 1 sleep divided by the total sleep time in hour. SFI and other polysomnographic parameters were statistically compared between the two nights. Results: SFI during baseline NPSG and nCPAP titration nights were $29.0{\pm}13.8$ and $15.2{\pm}8.8$, respectively, indicating a significant SFI decrease during nCPAP titration (t=9.7, p<0.01). SFI showed significant negative correlations with sleep efficiency (r=-0.60, p<0.01) and total sleep time (r=-0.45, p<0.01) and a positive correlation with RDI (r=0.28, p<0.01). Conclusion: Use of nCPAP, even during the titration, significantly decreases sleep fragmentation and improves sleep structure in OSAS patients. We suggest that SFI may be utilized as a measure of assessing OSAS severity and nCPAP efficacy.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.825-830
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• 2009

Pharmaceutical compounds enter the water environment through the diverse pathways. Because their concentration in the water environment was frequently detected in the level of ppt to ppb, the monitoring system should be optimized as much as possible for finding appropriate management policies and technical solutions. One Factor At a Time (OFAT) approach approximating the response with a single variable has been preferred for the optimization of LC-MS/MS operational conditions. However, it is common that variables in analytical instruments are interdependent. Therefore, the best condition could be found by using the statistical optimization method changing multiple variables at a time. In this research, response surface analysis (RSA) was applied to the LC-MS/MS analysis of emerging antibiotic compound, sulfamethoxazole, for the best sensitivity. In the screening test, fragmentation energy and collision voltage were selected as independent variables. They were changed simultaneously for the statistical optimization and a polynomial equation was fit to the data set. The correlation coefficient, $R^2$ valuerepresented 0.9947 and the error between the predicted and observed value showed only 3.41% at the random condition, fragmentation energy of 60 and collision voltage of 17 eV. Therefore, it was concluded that the model derived by RSA successfully predict the response. The optimal conditions identified by the model were fragmentation energy of 116.6 and collision voltage of 10.9 eV. This RSA can be extensively utilized for optimizing conditions of solid-phase extraction and liquid chromatography.

• Composites Research
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• v.25 no.6
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• pp.205-210
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• 2012

The single carbon fiber tensile test was performed with electrical resistance measurement. Tensile property of single carbon fiber which accompanied by the relationship between the electric resistance and the strain was investigated. Since the collected data showed a linear relationship between them, the coefficient of fiber slip ratio (FSR) was obtained by computation. The fragmentation specimen (FS) was tested under tensile loading, and the single carbon fiber broke first due to the stress transferring form matrix to reinforcing fiber. The stress distribution of carbon fiber could be observed via the electrical resistance change. Slipping between carbon fiber and matrix was predicted based on the fragmentation test results, and the FSR was used to evaluate interfacial adhesion comparatively. The large FSR indicated poor interfacial bonding. Work of adhesion between carbon fiber and matrix was measured to verify the FSR method, and two results exhibited a consistent conclusion.

• Composites Research
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• v.16 no.2
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• pp.68-73
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• 2003

Interfacial properties and electrical sensing fer fiber fracture in carbon and SiC fibers/epoxy composites were investigated by the electrical resistance measurement and fragmentation test. As fiber-embedded angle increased, the interfacial shear strength (IFSS) of two-type fiber composites decreased, and the elapsed time takes long until the infinity in electrical resistivity. The initial slope of electrical resistivity increased rapidly to the infinity at higher angle, whereas electrical resistivity increased gradually at small angle. Furthermore, both fiber composites with small embedded angle showed a fully-developed stress whitening pattern, whereas both composites with higher embedded angle exhibited a less developed stress whitening pattern. As embedded angle decreased, the gap between the fragments increased and the debonded length was wider for both fiber composites. Electro-micromechanical technique could be a feasible nondestructive evaluation to measure interfacial sensing properties depending on the fiber-embedded angle in conductive fiber reinforced composites.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.42-45
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• 2005

Interfacial evaluation of various combinations of both Flax and Hemp fibers/polypropylene were performed by using micromechanical test and nondestructive acoustic emission (AE). It can be because interfacial adhesion between the natural fiber surface and matrix plays an important role in controlling the overall mechanical properties of polymer composite materials by transferring the stress from the matrix to the fiber. It is necessary to characterize the interphase and the level of adhesion to understand the performance of the composites properly. Microfailure mechanism of single Flax fiber bundles were investigated using the combination of single fiber tensile test and nondestructive acoustic emission. Microfailure modes of the different natural fiber/polypropylene systems were observed using optical microscope and determined indirectly by AE and their FFT analysis.

• Journal of Chest Surgery
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• v.25 no.4
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• pp.412-417
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• 1992

Pulmonary artery aneurysm is Behcet`s disease is rare and can be fatal due to rupture. We experienced a case of pulmonary artery aneurysm in Behcet`s disease. The patient was 21 year old woman who was adimitted with three month history of dyspnea, fever and cough. On examination, she had aphthous ulcer in the mouth and erythema nodosum on the left popletial fossa and forearm, but didn`t have any lesion at eyes and genitalia. The latex fixation test for rheumatoid factor, VDRL test for syphillis, antinuclear antibody and LE cell test were all negatives. The third and fourth components of complement in the serum, serum immunoglobulin concentrations[IgG, IgM, IgA] were within normal range. The chest radiography revealed a 5x6cm sized radiopaque mass density in the left hilar region. Two months later, the mass was enlarged to 6x7cm. The IV-DSA showed a single aneurysm at the proximal part of left lower lobe artery with lingular segment artery and no distal perfusion by thombotic obstruction. The steroid therapy was done for a month, but symptoms not improved. We performed resection of lingular segment and lower lobe including the aneurysm. The microscopic findings of the operative specimen were intimal hyperplasia and fragmentation of the internal elastic fibers. She was improved without remarkable event, except infection of the operative wound.