• Solar Energy
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• v.6 no.2
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• pp.3-14
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• 1986

It is desirable to collect the solar thermal energy at relatively high temperature in order to minimize the size of thermal storage system and to enlarge the scope of solar thermal energy utilization. In this study, to develop a solar collector that has both advantages of collecting solar thermal energy at high temperature and fixing conveniently the collector system for long term period, a cylindrical parabolique concentrating solar collector (M.C.P.C.S.C) was designed, which has several rows of parabolique reflectors and thin thickness such as the flat-plate solar collector, maintaining the optical form of concentrating solar collector. The thermal performance of the M.C.P.C.S.C. newly designed in this study was analysed theoretically and experimentally. The results are summarized as follows: 1) prediction equation for outlet temperature, $T_o$, of heat transfer fluid and for the thermal efficiency, ${\eta}$, of the collector were derived as; o $$T_o=[C+B1_n(\frac{I_c(t)}{pv^3})]T_i$$ o $${\eta}=\frac{A}{A_c}\dot{m}[(C-1)+B1_n(E{\cdot}di^6\frac{I_c(t)}{\dot{m}^3})]\frac{T_i}{I_c(t)}$$ 2) When the insolation on the tilted solar collector surface, $I_c$, was $900-950W/m^2$ and the heat transfer fluid was not circulated in tubular absorber, the maximum temperature on the absorber surface was $100-118^{\circ}C$, this result suggested that the heat transfer fluid could be heated up to $98-116^{\circ}C$. The maximum temperature on the absorber surface was decreased with the increase of the collector shape factor, $L_p/L_w$ 3) There was a good agreement between the experimental and theoretical value of solar collector efficiency, ${\eta}$, which was proportional to the collector shape factor, $L_p/L_w$ 4) It is desirable to continue the study on the relationship between the collector shape factor, $L_p/L_w$, and the thermal efficiency of solar collector.

• Preventive Nutrition and Food Science
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• v.1 no.2
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• pp.214-219
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• 1996

This study was done to investigate effects of n-s fatty acids and vitamin E supplement on the preneoplastic hepatic enzyme altered foci and cholesterol metabolism in experimental hepatocarcinogenesis system. Weaning male Sprague-Dawley rats were fed the diet containing either 15% corn oil(CO) or sardine oil(SO) with or without vitamin E 800IU supplementation for 12 weeks. After two weeks of feeding, rats were intraper-itoneally injected with a single dose of diethylnitrosamine(DEN:200mg/kg, BW). At the 4th week, rats were given the diet containing 0.02% acetylaminofluorene(AAF) for next 4 weeks. At the 6th Week, 0.05% pheno-barbital was incorporated into diet for 6 weeks. At the end of 12th week, rats were sacrificed and hepatic glutathions S-transferase placental form positive(GST_{TEX}$P^{+}${/TEX}) foci and serum and liver cholesterol levels were determined. GST_{TEX}$P^{+}${/TEX} formation was significantly decreased by SO feeding when compared with Co feeding but it tended to be enhanced by vitamin E supplementation. Histopathological changes were similar to patterns of GST_{TEX}$P^{+}${/TEX} formation in almost all dietary groups. Serum and hepatic cholesterol levels of SO fed groups were significantly lower than those of CO fed groups. Carcinogen treatments significantly increased serum and liver cholesterol levels in CO fed groups but not in SO fed groups. Correlation data showed a positive correlation(${\gamma}$=0.83, p<0.01) between serum cholesterol level GST_{TEX}$P^{+}${/TEX} foci area. These results indicate that sardine oil as a m-3 fatty acid source may have a reducing effect in rat hepatocarcinogenesis by the altheration of cholesterol metabolism.

• Tuberculosis and Respiratory Diseases
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• v.79 no.4
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• pp.295-301
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• 2016

Background: Specific immunoglobulin E (IgE) sensitization to staphylococcal enterotoxin (SE) has been recently considered to be related to allergic disease, including asthma. Despite studies on specific IgE (sIgE) to SE and its relationship to asthma diagnosis and severity, the association of sIgE to SE with airway hyperresponsiveness (AHR) remains unclear. Methods: We enrolled 81 asthma patients admitted to the Severance Hospital in Korea from March 1, 2013, to February 28, 2015 and retrospectively reviewed the electronic medical records of the enrolled subjects. The serum levels of sIgE to SE (A/B) of all subjects was measured using the ImmunoCAP 250 (Phadia) system with SE-sIgE positive defined as >0.10 kU/mL. Results: The SE-sIgE level was not significantly correlated with asthma severity (forced expiratory volume in 1 second [$FEV_1$], $FEV_1$/forced vital capacity, sputum eosinophils, and serum eosinophils), whereas the SE-sIgE level in patients with positive AHR ($mean{\pm}standard$ error of the mean, $0.606{\pm}0.273kU/mL$) was significantly higher than that in patients with negative AHR ($0.062{\pm}0.015kU/mL$, p=0.034). In regression analysis, SE sensitization (sIgE to SE ${\geq}0.010kU/mL$) was a significant risk factor for AHR, after adjustment for age, sex, $FEV_1$, and sputum eosinophils (odds ratio, 7.090; 95% confidence interval, 1.180-42.600; p=0.032). Prevalence of SE sensitization was higher in patients with allergic rhinitis and non-atopic asthma patients, as compared to patients without allergic rhinitis and atopic asthma patients, respectively, but without statistical significance. Conclusion: SE sensitization is significantly associated with AHR.

• Journal of the Korean Society of Systems Engineering
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• v.1 no.1
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• pp.26-31
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• 2005

In order to care about preserving the environment for future generations, each country has been required to make the laws of the environment. So manufacturers must design, manufacture and sell goods that meet customer's need and must do this while meeting the needs of the environment. In this research we have developed product structure and configuration management system that treats electronic catalogs for recycling of train parts. This research focused on two system. One is JAVA-based electronic catalog that give the information about recycling of train parts. The other is product structure and configuration management system based on electronic catalog and Bill of Materials(B.O.M).

• The Korean Journal of Food And Nutrition
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• v.6 no.3
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• pp.169-177
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• 1993

The conversion of glutamate by glutamine synthetase Is the endergonic reaction that demands ATP as its energy source. In order to supply efficiently ATP that is demanded in the conversion of glutamate to glutamine, the ATP- generating system by acetate kinase partially purified from Escherichia coli K-12 was coupled with glutamine synthetase partially purified 5. coli K-12 Pgln6. The optinum conditions of the coupled reaction were investigated. As the result, the highest conversion of glutamate to glutamine was shown In the reaction mixture containing 100mM glutamate, 100mM NHtCl, 50M acetyl phosphate, 5mM ADP, 40M MgCl2, 300mM potassium phosphate buffer (pH 7.5), 5mM MnCl2, Under this condition, the most effective concentrations of enzyme were 70unit/ml glutamine synthetase and 99unit/ml acetate kinase. Under the optinum conditions, 98% of 100mM glutamate was converted to glutamine within 6 hours.

• Korean Journal of Veterinary Service
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• v.35 no.2
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• pp.119-128
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• 2012

This study was performed to investigate the freshness and nutritive components of eggs from Incheon area. The eggs of 64 brands collected from 7 hypermarkets and 6 brands collected from farms were examined to test the Haugh unit (HU), egg yolk index and specific gravity. HU and specific gravity were higher in farm eggs than in hypermarket eggs (P<0.05), and there was no difference in the egg yolk index. Among hypermarket eggs, HU and egg yolk index were higher in the graded eggs than in non-graded eggs (P<0.05), and specific gravity was not different between them. HU and egg yolk index of the eggs collected in March were higher than those in August (P<0.05). To monitor the bacterial contamination, total coliforms, total bacterial counts (TBC) and Salmonella enteritidis were examined. Salmonella enteritidis and total coliforms were not detected from all eggs. TBC of farm eggs were less than $10^1$ CFU/mL in all samples and TBC of hypermarket eggs were less than $10^1$ CFU/mL in 187 samples, $10^1{\sim}10^2$ CFU/mL in 3 samples and $10^3{\sim}10^4$ CFU/mL in 2 samples, respectively. Antimicrobial residues were not detected from all eggs tested. The vitamin E contents in the vitamin E enriched eggs from 6 brands hypermarket were 1.98~22.96 mg/yolk100 g ($14.04{\pm}8.81$ mg/yolk100g), and those of 5 brands among them were higher than the average of ordinary eggs. In one brand egg, vitamin E content was lower than the average of ordinary eggs. The vitamin E contents of ordinary eggs were 1.75~16.36 mg/yolk100 g (average $5.57{\pm}2.76$ mg/yolk100 g) and there were no price differences between vitamin E enriched eggs and ordinary eggs. In the contents of vitamin E, docosahexaenoic acid (DHA) and cholesterol, there were no significant differences according to the price. These results suggests that egg production, distribution, and management system should be improved for supplying fresh eggs to consumers at reasonable prices.

• Biomolecules & Therapeutics
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• v.6 no.4
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• pp.351-357
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• 1998

In order to understand the mechanism of the regulation of CYPIAI gene expression and ethoxy-resorufin deethylase (EROD) activity in ex vivo system, we have studied the action of TCDD and 3MC in theisolated perfused male rat liver. CYPIAI myNA level and EROD activity were measured in rat liver that wasisolated and perfused with va.ious chemicals such as 2,3,7,8-tet.achlorodibenzo-p-dioxin (TCDD), 3-methyl-cholanthrene (3MC), $17{\beta}$-est.adios ($E_2$), morin. TCDD or 3MC alone perfusion into male rat liver resulted in increase of CYPIAI mRNA level and the magnitude of stimulation was one and half times higher with TCDD treatment than 3MC treatment. However $E_2$ perfusion into male rat liver showed slight stimulation of CYPIAI mRNA level. When $10_{-8}$ M $E_2$ was perfused concomitantly with either $10_{-9}$ M TCDD or $10_{-9}$ M 3MC, stimulated CYPIAI mRNA by either TCDD or 3MC was inhibited. Morin was examined for its effects on CYPIAI mRNA level and result was similar to that was observed with estrogen except that morin alone did not change the level of CYPIAI mRNA. EROD activity was also stimulated with either TCDD or 3MC perfusion, and the magnitude of EROD stiumlation was similar to that of CYPIAI mRNA stimulation in response to TCDD or 3MC perfusion. This data is different from the data that we have obtained with female rat liver. Concomitant perfusion either $E_2$ or morin with TCDD or 3MC inhibited 3MC perFusion or TCDD perfusion stimulated EROD activity. These data confirm the hypothesis that TCDD and 3MC might act through the same mechanism of action on the regulation of CYPIAI gene expression in male rat liver.

• Journal of Astronomy and Space Sciences
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• v.16 no.1
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• pp.11-20
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• 1999

In this paper all the photoelectric times of minimum for the triple star SW Lyn have been analyzed in terms of light-time effect due to the third-body and secular period decreases induced by mass transfer process. The light-time orbit determined recently by Ogloza et al.(1998) were modified and improved. And it is found that the orbital period of SW Lyn have been decreasing secularly. The third-body revolves around the mass center of triple stars every $5^y.77$ in a highly eccentric elliptical orbit(e=0.61). The third-body with a minimum mass of $1.13M_{odot}$ may be a binary or a white dwarf. The rate of secular period-decrease were obtained as ${Delta}P/P=-12.45{ imes}10^{-11}$, implying the mass-transfer from the massive primary star to the secondary. The mass losing rate from the primary were calculated as about $1.24{ imes}10^{-8}M_{odot}/y$. It is noticed that the mass-transfer in SW Lyn system is opposite in direction to that deduced from it's Roche geometry by previous investigators.

• Polymer(Korea)
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• v.33 no.5
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• pp.441-445
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• 2009

In order to develop an intelligent delivery system for cosmetic active agents (e.g., arbutin, ascorbic acid, and adenosine), pH-responsive P(MAA-co-PEGMA) hydrogel particles having an average size of approx. $2{\mu}m$ and spherical shape were synthesized via dispersion photopolymerization. There was a drastic change in the swelling ratio of P (MAA-co-PEGMA) hydro gels at a pH 5, which is the $pK_a$ of the hydrogel. To determine the factors that have an effect on the loading of cosmetic active agents into the hydrogel, the loading efficiency of the active agents was investigated at various MAA and EG compositions of the hydrogel and the loading pH conditions. When the MAA contents in the hydrogel decreased, the loading efficiency of the active agents increased. In loading experiments with different pH conditions, the active agents showed higher loading efficiency into the hydrogel at the pH where the hydrogel was at the swollen state than at the pH where the electrostatic repulsion was minimized.

• Polymer(Korea)
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• v.32 no.3
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• pp.219-229
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• 2008

A pH sensitive ternary copolymer gel was synthesized in the presence of ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent through radical polymerization of vinyl acetate (VA), acrylic acid (AA) and methyl acrylate(MA) with a weight ratio of 1 : 1.3 : 1. A number of experiments were carried out to determine the swelling behavior of the gel under a variety of pH conditions of the swelling medium. As the pH of the swelling medium was changed from 1.0 to 8.0 at $37^{\circ}C$, the gel showed a shift in the pH-dependent swelling behavior from Fickian (n=0.3447) to non-Fickian (n=0.9125). The resulting swelling parameters were analyzed using graphical and statistical methods. The results showed that the swelling of the gel was controlled by the pH of the medium, i.e. $n=n_o{\exp}(S_{C}pH)$, where n is the diffusion exponent, $n_o(=28.9645{\times}10^{-2})$ is the pre-exponential factor and $S_C$(=0.1417) is pH sensitivity coefficient. The swelling behavior of the gel was also examined in aliphatic alcohols. The results showed that the rate of swelling increased with increasing number of carbon atoms in the alcoholic molecular chain.