• Journal of Chest Surgery
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• v.30 no.11
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• pp.1055-1061
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• 1997

In the field of the experimental lung transplantation, we analyzed the CT findings of acute rejection, infection in the left single allotransplanted lung of adult mongrel dogs, and the CT findings were compared with the histological findings obtained by the lung biopsy Twenty two adult mongrel dogs were divided into two groups(Donor and recipient group). Donor lungs were flushed with LPDG(low pota,ilium dextral glucose) solution(n=4) or modified Euro-collins solution(n=7) and preserved over 20 hours with $10^{\circ}C(1$ case preservation for 4hours). After left single lung transplantation, the chest X-ray and sequential computed tomogram were performed with concomitant hemodynamic study and arterial blood gas analysis on immediate postoperative period, postoperative 3rd day and postoperative 7th day. Two of eleven transplanted lungs had acute rejection which was represented as moderate infiltration at immediate or 1st postoperative d y but became extensive infiltration at postoperative 3rd day on CT. There were showed one case of bronchopleural fistula, six cases of pneumonia and two cases of pulmonary infarction. In one rejection cases, the opacity of transplanted lung was improved by injection of methylprednisolone 500mg daily during 3 days. We concluded that CT was a useful noninvasive evaluation parameter after lung transplantation and the serial CT scan enabled early detection of acute rejection.

• Clean Technology
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• v.21 no.4
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• pp.271-277
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• 2015

A photocatalyst which mixed by the commercialized P25-TiO₂ and a synthesized Ag_xO was used in an appropriate weight ratio to effectively produce hydrogen gas in this study. The Ag_xOs were synthesized with the conventional sol-gel method, and tetramethylammonium hydroxides were added at the synthesis process in order to stabilize the solutions, and then the solutions were heat-treated at the temperatures of -5, 25, and 50 ℃, resulted to obtain the three types of silver oxides. Physicochemical properties of the synthesized Ag_xOs were identified through X-ray diffraction analysis (XRD), scanning emission microscopy (SEM), ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). In the photolysis results of water/methanol (weight ratio 1:1) solution, the mixture of P25-TiO₂/Ag_xO exhibited a significantly higher hydrogen gases evolution, compared to that of pure P25-TiO₂. Additionally, the addition of H₂O₂ as an supplement oxidant and in Ag_xO synthesized at 50 ℃ improved the hydrogen production efficiency. In particular, the emitted hydrogen gases reached to 13,000 μmol during 8 hours when a mixed catalyst, Ag_xO of 0.1 g and P25-TiO₂ of 0.9 g, were used.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.2
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• pp.119-125
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• 2017

Ablative material in a rocket nozzle is exposed to high temperature combustion gas, thus undergoes complicated thermal/chemical change in terms of chemical destruction of surface and thermal decomposition of inner material. Therefore, method for conjugate analysis of thermal response inside carbon/phenolic material including rocket nozzle flow, surface chemical reaction and thermal decomposition is developed in this research. CFD is used to simulate flow field inside nozzle and conduction in the ablative material. A change in material density and a heat absorption caused by the thermal decomposition is considered in solid energy equation. And algebraic equation under boundary layer assumption is used to deduce reaction rate on the surface and resulting destruction of the surface. In order to test the developed method, small rocket nozzle is solved numerically. Although the ablation of nozzle throat is deduced to be higher than the experiment, shape change and temperature distribution inside material is well predicted. Error in temperature with experimental results in rapid heating region is found to be within 100 K.

• Journal of Life Science
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• v.20 no.3
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• pp.356-364
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• 2010

This study was carried out to investigate the exposure pathway of PBDEs in human breast milk collected from new mothers residing in Chuncheon, a comparatively clean area in Korea. The congeners of PBDE in 22 human breast milk samples were analyzed using a high resolution gas chromatography with a high resolution mass detector. The residue level of ${\sum}PBDEs$ was higher in primipara subjects than in multipara subjects (p<0.05). The levels in this study were similar to those of people in some Asian and European countries, but were lower than those of people in north America. In the congener profiles, BDE-47 (mean contribution=36.1%) was predominant, followed by BDE-153 (27%), BDE-99 (11.7%), BDE-100 (11.1%), BDE-28 (7.9%) and BDE-183 (3.5%). The sum of BDE-47 and BDE-153 accounted for more than 50% of ${\sum}PBDEs$ in most samples. BDE-47 was highly correlated with ${\sum}PBDEs$ (r=0.94, p<0.001). No strong trend was observed between PBDE levels and a number of key biological factors (women's age, weight, height and body mass index) examined in this study, however, weak correlations were observed in PBDE levels measured against dietary habits, particularly in fish consumption frequency. It seems that Korean people might be exposed to multiple sources including products of PBDEs, and particularly food resources.

• Journal of Microbiology
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• v.45 no.5
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• pp.460-465
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• 2007

This study was carried out in order to investigate the potential of using plant oils derived from Leptospermum petersonii Bailey and Syzygium aromaticum L. Merr. Et Perry as natural antifungal agents. The antifungal effects of essential oils at concentrations of 0.05, 0.1, 0.15, and 0.2 mg/ml on the dermatophytes Microsporum canis (KCTC 6591), Trichophyton mentagrophytes (KCTC 6077), Trichophyton rubrum (KCCM 60443), Epidermophyton floccosum (KCCM 11667), and Microsporum gypseum were evaluated using the agar diffusion method. The major constituents of the active fraction against the dermatophytes were identified by gas chromatography-mass spectrometry and high-performance liquid chromatography analysis. The antifungal activities of S. aromaticum oil (clove oil) against the dermatophytes tested were highest at a concentration of 0.2mg/ml, with an effectiveness of more than 60%. Hyphal growth was completely inhibited in T. mentagrophytes, T. rubrum, and M. gypseum by treatment with clove oil at a concentration of 0.2 mg/ml. Eugenol was the most effective antifungal constituent of clove oil against the dermatophytes T. mentagrophytes and M. canis. Morphological changes in the hyphae of T. mentagrophytes, such as damage to the cell wall and cell membrane and the expansion of the endoplasmic reticulum, after treatment with 0.11 mg/ml eugenol were observed by transmission electron microscopy (TEM). At a concentration of 0.2 mg/ml, L. petersonii oil (LPO) was more than 90% effective against all of the dermatophytes tested, with the exception of T. rubrum. Geranial was determined to be the most active antifungal constituent of L. petersonii oil. Taken together, the results of this study demonstrate that clove and tea tree oils exhibited significant antifungal activities against the dermatophytes tested in this study.

• Korean Journal of Materials Research
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• v.9 no.10
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• pp.1006-1011
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• 1999

B-doped hydrogenated amorphous silicon carbide (a-SiC:H) thin films were prepared by plasma-enhanced chemical-vapor deposition in a gas mixture of $SiH_4$, $CH_4$ and $B_2H_6$. Microstructures and chemical properties of a-SiC:H films grown with varing the volume ratio of $CH_4$ to $SiH_4$ were characterized with various analysis methods including scanning electron microscopy(SEM), X-ray diffractometry(XRD), Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy. X-ray photoelectron spectroscopy(XPS), UV absorption spectroscopy and photoconductivity measurements. While Si:H films grown without $CH_4$ showed amorphous state, the addition of $CH_4$ during deposition enhanced the development of a microcrystalline phase. By introducing C atoms into the film, Si-Si and Si--$\textrm{H}_{n}$ bonds of a -Si:H films were gradually replaced by Si-C, C-C, and Si--$\textrm{C}_{n}\textrm{H}_{m}$ bonds. Consequently, the electrical resistivity and optical bandgap of a-SiC:H films were increased with the C concentration in the film.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.6
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• pp.731-737
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• 1992

The specific attributes of aroma quality of canned tuna meat were investigated before and during refrigerated storage. Fresh, cooked tuna, beefy and meaty flavor notes of canned tuna meat were changed to card-boardy(1 week storage), oxidized fat-like(2 weeks storage), fatty acid-like and heavy oxidized fat-like(3 weeks storage), and then moldy and painty(4 weeks storage) flavor notes during storage in refrigerator at $4^{\circ}C.$ More than 126 peaks of volatile compounds collected from canned tuna meat were separated on Carbowax 20M capillary column of gas chromatographic analysis. Of the peaks, 54 compounds were identified by mass spectral data, matching $I_E$ values, and sniffing the effluent of each peak from GC detector. The contents of many low molecular weight compounds eluted with early retention times were decreased, whereas some other new compounds eluted with longer retention time were formed during storage. The compounds increased up to 3 weeks of storage and then decreased at extended storage time(4 weeks) were 1-penten-3-ol, 3-penten-2-ol, heptanal, limonene, 1-pentanol, octanal, 1-hexanol, nonanal, 2-octanone, 2-nonanone, 1-heptanol, benzaldehytde and some methyl substituted benzenes. p-Thiocresol, 2-chlorophenol, and 2-heptylthiophene were formed after 4 weeks of storage, but not detected in fresh canned tuna. Therefore, these compounds could be used as indicators for the quality changes during refrigerated storage.

• Applied Biological Chemistry
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• v.29 no.3
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• pp.318-323
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• 1986

We empolyed gel filtraction, polyacrylamide gel electrophoresis, amino acid autoanalyzer, thin layer chromatography for determining protein and lipid composition in walnut. The walnut contained 22.18% of crude protein and 64.23% of crude lipid. Glutamic acid (38.60%) was the major amino acid in soluble protein, followed by arginine and aspartic acid. The sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis showed 12 band in soluble protein of walnut, and collection rate of main protein fraction purified by Sephadex G-150 was 60.67%. The molecular weight for the main protein was estimated to be 43,000. The lipid fraction obtained by silicic acid column chromatography were mainly composed of about 93.05% neutral lipid, whereas compound lipid was only 7.0% level. Among the neutral lipid by thin layer chromatography, triglyceride was 82.05%, sterol ester and free fatty acid were 3.86% and 4.80%, repectively. The predominant fatty acids of total and neutral lipids were linoleic acid $(64.48{\sim}69.98%)$ and oleic acid $(13.89{\sim}15.36%)$. The major fatty acids of triglyceride separated from neutral lipid were linolenic acid (69.98%).

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.389-400
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• 2011

A high-performance liquid chromatographic (HPLC) method was developed to determine residues of phenothrin and silafluofen, known as synthetic pyrethroids, in agricultural commodities. Insecticide residues were extracted with acetone from representative samples of four crops which comprised rice, apple, pepper and cabbage. The extract was purified serially by liquid-liquid partition and Florisil column chromatography. For rice and pepper samples, acetonitrile/n-hexane partition was additionally adopted to remove nonpolar interferences. Reversed phase HPLC using an octadecylsilyl column was successfully applied to separate two phenothrin isomers and silafluofen from sample co-extractives. Intact parent compounds were sensitively detected by ultraviolet absorption at 226 nm. Recovery experiment at the quantitation limit validated that the proposed method could apparently determine phenothrin and silafluofen residues at 0.02 and 0.01 mg/kg, respectively. Mean recoveries of phenothrin and silafluofen from four crop samples fortified at three levels in triplicate were in the range of 82.4~109.8% and 83.7~109.8%, respectively. Relative standard deviations of the analytical method were all less than 10%, irrespective of crop types and spiking levels. A selected-ion monitoring (SIM) LC/mass spectrometry (MS) with electrospray ionization was provided to confirm the suspected residue of phenothrin, even though no sufficient ionization of silafluofen was obtained. Both phenothrin and silafluofen could be successfully confirmed by gas chromatography/MS SIM with electron impact at 70 eV. The proposed method is sensitive, repeatable and rapid enough to apply to officially routine inspection of agricultural products.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.6
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• pp.397-405
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• 2012

In this study, performance evaluation of newly developed technology for the economical and safe removal of volatile organic compounds (VOCs) coming out from electronic devices washing operation and offensive odor induction materials was made. Metal oxidization catalyst has shown 50% of removal efficiency at the temperature of $220^{\circ}C$. Composite metal oxidization catalyst applied in this study has shown that the actual catalysis has started at the temperature of $100^{\circ}C$. Comprehensive analysis on the catalyst property using Mn-Cu metal oxidization catalyst in the pilot-scale unit was made and the removal efficiency was variable with temperature and space velocity. Full-scale unit developed based on the pilot-scale unit operation has shown 95% of removal efficiency at the temperature of $160^{\circ}C$. Optimum elimination effective rates for the space velocity was found to be $6,000hr^{-1}$. The most appropriate processing treatment range for the inflow concentration of VOCs was between 200 ppm to 4,000 ppm. Catalyst control temperature showed high destruction efficiency at $150{\sim}200^{\circ}C$ degrees Celsius in 90~99%. External heat source was not necessary due to the self-heat reaction incase of VOCs inflow concentration is more than 1,000 ppm. Equipment and fuel costs compared to the conventional RTO/RCO method can be reduced by 50% and 75% respectively. And it was checked when there was poisoning for sulfide and acid gas.