• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.100-109
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• 1999

This study evaluates the pretreatment for analysis of benzidine metabolites in urine by measuring the recovery rates according to the temperature and periods of storage of the urine. By the solid phas e extraction, the recovery rates of basic hydrolysis are benzidine 67.4 %, monoacetylbenzidine 105.1 %, and diacetylbenzidine 115.8 %, respectively. By the liquid extraction, the recovery rates of back-extraction into 0.1 M perchloric acid are benzidine 105.7%, monoacetylbenzidine 94.2 %, diacetylbenzidine 72.8 %, respectively. The difference of the recovery rates between the back-extraction into 0.1 M HCl and 0.1 M perchloic acid after basic hydrolysis are 101 % and 98.8 %, respectively. When the recovery rates of the urinary s amples of pH 3, pH 7, pH 12 at $25^{\circ}C$ and $-76^{\circ}C$ are compared for four weeks, there are no differences according to the temperature and the periods of storage. The above results show that the solid phase extraction and back-extraction by 0.1 M perchloric acid after basic hydrolys is are suitable for the analysis of benzidine metabolites. There are no difference of the recovery rates of the urinary samples stored at $25^{\circ}C$ and $-76^{\circ}C$ at pH 3, pH 7, pH 12, respectively for 28 days.

• Food Science and Biotechnology
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• v.15 no.4
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• pp.612-616
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• 2006

The protective effect of water extract of ash tree leaves (ALE) against oxidative damages was investigated in paracetamol-induced BALB/c mice. Biochemical analysis of anti-oxidative enzymes, immunoblot analyses of hepatic cytochrome P450 2El (CYP2E1), and the gene expression of tumor necrosis factor (TNF-${\alpha}$) were examined to determine the extract's protective effect and its possible mechanisms. BALB/c mice were divided into three groups: normal, paracetamol-administered, and ALE-pretreated groups. A single dose of paracetamol led to a marked increase in lipid peroxidation as measured by malondialdehyde (MDA). This was associated with a significant reduction in the hepatic antioxidant system, e.g., glutathione (GSH). Paracetamol administration also significantly elevated the expression of CYP2E1, according to immunoblot analysis, and of TNF-${\alpha}$ mRNA in liver. However, ALE pretreatment prior to the administration of paracetamol significantly decreased hepatic MDA levels. ALE restored hepatic glutathione and catalase levels and suppressed the expression of CYP2E1 and TNF-${\alpha}$ observed in inflammatory tissues. Moreover, ALE restored mitochondrial ATP content depleted by the drug administration. These results show that the extract of ash tree leaves protects against paracetamol-induced oxidative damages by blocking oxidative stress and CYP2E1-mediated paracetamol bioactivation.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.405-406
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• 2006

Raw materials from different sources, produced by a given process and having equal chemical composition, are supposed to be equivalent. The differences in sintering behavior have been investigated on P/M steels obtained from four diffusion-bonded powders (Fe + Ni + Cu + Mo) on atomized iron base, at the same alloy contents. Two levels of carbon and two sintering conditions have been investigated. Dimensional changes, C content, hardness, microhardness pattern, universal hardness, fractal analysis, pore features, microstructure features, and rupture strength have been compared to characterize different raw materials. The results show that the claimed equivalence is not confirmed by experimental data.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.813-815
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• 1992

Accurate Capacitance-Voltage characteristics of Metal-Insulator-Semiconductor (MIS) devices in narrow band-gap semiconductors are presented. The unique band structure of narrow band-gap semiconductors is taken into account such as non-parabolicity and degeneracy. Compensated and partially ionized impurities either in the bulk or the space charge region are also considered. HgCdTe is a defect semiconductor, so this approach is very important for characterization and analysis of MIS devices.

• Journal of Biosystems Engineering
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• v.38 no.4
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• pp.335-340
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• 2013

Purpose: This study was performed to develop a lateral flow strip sensor for the detection of pathogenic Escherichia coli O157:H7 in various samples. Also, feasibility of using an image analysis method to improve the interpretation of the strip sensor was evaluated. Methods: The lateral flow strip sensor has been fabricated based on nitrocellulose lateral-flow membrane. Colloidal gold and E. coli O157:H7 antibodies were used as a tag and a receptor, respectively. Manually spotted E. coli O157:H7 antibody and anti-mouse antibody on nitrocellulose membrane were used as test and control dots, respectively. Feasibility of the lateral flow strip sensor to detect E. coli O157:H7 were evaluated with serially diluted E. coli O157:H7 cells in PBS or food samples. Test results of the lateral flow strip sensor were measured with an image analysis method. Results: The intensity of the test dot started to increase with higher concentration of the cells were introduced. The sensitivities of the sensor were both $10^4$ CFU/mL Escherichia coli O157:H7 spiked in PBS and in chicken meat extract, respectively. Conclusions: The lateral flow strip sensor and image analysis method could detect E. coli O157:H7 in 20 min, which is significantly quicker than conventional plate counting method.

• Bulletin of the Korean Chemical Society
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• v.5 no.2
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• pp.79-82
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• 1984

This study concerns about catalyic cracking of iso-octane over cation ($Cd^{2+},\;Ca^{2+}\;and\;La^{3+}$) exchange mordenites. It deals with mordenite shape selectivity and with kinetics of this catalytic reaction. The striking feature was that over the region of cracking temperature investigated, 523-665K, the yield of isobutene was predominant, relative to that of larger or smaller carbon chain(s). This permits kinetic analysis of the heterogeneous catalytic system in terms of the modified pulse-version microcatalytic chromatography. The observed activation energy ($E_a,\;KJ\;mol^{-1}$) was found to be 46 for Cd-M, 57 for Ca-M and 59 for La-M, respectively.

• Journal of Naturopathy
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• v.10 no.2
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• pp.108-113
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• 2021

Background: Results on the action of antioxidants in extracts of Equisetum hyemale stems and roots have already been reported, but the antioxidant properties have not been analyzed. Purpose: This study was to determine the molecular structure of antioxidants in substances extracted from E. hyemale stems and roots. Methods: Component analysis was analyzed by HPLC and LC-MS after extraction with hot water and ethyl alcohol. Results: The HPLC chromatogram of stem and root extracts showed four significant peaks at a wavelength of 205 nm. Peak 1 at 280 nm is a typical simple phenolic type, and both peaks 2-4 near 280 nm and 370 nm are typical flavonoid glycosides. As for the antioxidant level of the extract by HPLC analysis, the sum of the peaks at 740 nm was the highest at 3,669 mAU in the 100% ethanol extract, 3,096 mAU in the 70% ethanol extract, and 2,868 mAU in the hot water extract. As a result of LC-MS analysis of the antioxidant extract, kaempferol-3-sophoroside-7-glucoside with a molecular weight of 772 da at peak 3, and kaempferol-3-sophoroside-8-glucoside with a molecular weight of 788 and 772 at peak 4 was identified. Conclusions: The above results show that two types of antioxidants were identified in the antioxidant extract of E. hyemale exrtracts. Therefore, the potential as a raw material for functional cosmetics has increased.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.169-175
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• 2009

In this experiment molybdeum oxide($MoO_3$) films were prepared by a magnetic null discharge(MND) sputtering system and fundamental properties by XRD, XPS and SEM analysis were investigated. The initial and mean insulation resistance of the same with $MoO_3$ film were about 1.4[$M{\Omega}$] and 800[$k{\Omega}$] under the condition of applied voltage of 400[V]. The preferred orientation in the films changed from(100) to (210) with substrate temperature. Two XPS peaks of the $MoO_3$ photoelectron were detected at the binding energies of 228.9[eV] and 232.4[eV], while the binding energy of the O1s peak was 532.6[eV]. The substrate temperature and reactivity gives large effects to the structure and growth of the film and system is also very useful for performing the uniform reactive deposition. It can be found from the result of a $MoO_3$ film deposition that the system is very useful for performing the uniform reactive sputtering.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.90-95
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• 2008

An SHGC(Solar Heat Gain Coefficient) is a determinant of total flux of solar radiation coming indoor and a critical factor in evaluating heating and cooling load. U-value represents heat loss while SHGC denominates heat gain. Recently, windows with high solar gain, mid solar gain or low solar gain are being produced with the development of Low-E coating technology. This study evaluated changes in energy consumption for heating and cooling according to changes in SHGC when using double-layered Low-E glass and triple layered Low-E glass in relation to double layered clear glass as base glass. An Office was chosen for the evaluation. For deriving optical properties of each window, WINDOW 5 by LBNL, an U.S. based company. and the results were analyzed to evaluate performance of heat and cooling energy on anannual basis using ESP-r, an energy interpretation program. Compared to the energy consumption of the double layered clear glass, the double layered Low-E glass with high solar gain consumed $69.5kWh/m^2,yr$, 9% more than the double layered clear glass in cooling energy. The one with mid solar gain consumed $63.1kWh/m^2,yr$, 1% less than the base glass while the one with low solar gain consumed $57.6kWh/m^2,yr$, 10% less than the base glass. When it comes to tripled layered glass, the ones with high solar showed 2% of increase respectively while the one with mid solar gain and low solar gain resulted 5% and 11% in decrease in energy consumption due to low acquisition of solar radiation. With respect to cooling energy. it was found that the lower the SHGC. the less energy consumption becomes.

• The Korea Journal of Herbology
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• v.27 no.4
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• pp.73-80
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• 2012

Objectives : Under normal condition melanin protects the skin from extracellular stimuli including ultraviolet (UV)-induced oxidative skin damages, but excess production and accumulation of melanin can induce hyperpigmentation causing esthetic problems. Therefore, in this study we tried to search for natural skin whitening materials from marine natural resources. Methods : Water and ethanol extracts of marine natural resources were prepared from Porphyra thalli (PT), Laminariae thallus (LT), Ostreae concha (OC), Sargassum thallus (ST), Undaria thallus (UT), Codium thalli (CT), Enteromorpha thalli (ET), Syngnathoides biaculeatus (SB), and Hippocampus coronatus (Hc). Their effects against UVB and ${\alpha}$-melanocyte stimulating hormone (${\alpha}$-MSH)-induced melanogenesis were investigated based on melanin formation in B16 mouse melanoma cells. The mRNA and protein expression of enzymes involved in the melanogenic process were further examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis, respectively. Results : Water extract of Ostreae concha (OCW/E) effectively inhibited UVB and ${\alpha}$-MSH-induced melanin production in B16 melanocytes, which seemed to be mediated by inhibition of mRNA expression of tyrosinase and tyrosinase-related protein 1 (TRP-1). In another experiment, ethanol extracts from Porphyra thalli (PTE/E), Laminariae thallus (LTE/E), Sargassum thallus (STE/E), Undaria thallus (UTE/E), Codium thalli (CTE/E), Syngnathoides biaculeatus (SBE/E), and Hippocampus coronatus (HcE/E) significantly suppressed UVB and ${\alpha}$-MSH-induced melanin formation. Furthermore, ethylacetate fraction isolated form LTE/E (LTE/EEt) decreased UVB and ${\alpha}$-MSH-elevated extracellular melanin levels via inhibition of tyrosinase protein expression. Conclutions : These results suggest that marine natural resources such as Porphyra thalli, Laminariae thallus, Ostreae concha, Sargassum thallus, Undaria thallus, Codium thalli, Syngnathoides biaculeatus and Hippocampus coronatus have anti-melanogenic effects, thereby exhibiting high potentials to be utilized as one of the ingredients for the development of new whitening functional cosmetics.