• Journal of Ginseng Research
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• v.12 no.2
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• pp.128-134
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• 1988

The effect of the saponin fraction extracted from Panax ginseng C.A. Meyer on the antioxidant activity of $\alpha$-tocopherol was investigated in vitro as well as in vivo. Microsomal preparation of rat(Winter, 180-200g) liver was incubated in the mixture containing NADPH, $Fe^{3+}$, ATP, $\alpha$-tocopherol with and/or without ginseng saponin fraction for 30 minutes and the malondialdehyde formed was assayed and found that the saponin fraction stimulated the antioxidant activity of $\alpha$-tocopherol cooperatively. It was also realized that the cooperative stimulation of the antioxidant activity of $\alpha$-tocopherol was most eminent when the concentration of the saponin fraction was around $10^{-5}$% in the reaction mixture. Alcoholic suspension of $\alpha$-tocopherol with and f or without ginseng saponin fraction was administered orally to rats in which the lipid preoccupation was induced by ethanol administration and the lipid peroxide contents of the liver were assayed at certain periods of time after $\alpha$-tocopherol administration in this animal. From the previous work and present experimental results, it seemed that the saponin fraction accelerated the absorption of $\alpha$-tocopherol and therefore stimulated the antioxidant activity of $\alpha$-tocopherol more effectively in the animal body.

• Journal of the Korean Society of Safety
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• v.28 no.6
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• pp.6-10
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• 2013

A numerical reproducibility of the backdraft phenomena in a compartment was investigated. The prediction performance of two combustion models, the mixture fraction and finite chemistry models, were tested for the backdraft phenomena using the FDS code developed by the NIST. The mixture fraction model could not predict the flame propagation in a fuel-air mixture as well as the backdraft phenomena. However, the finite chemistry model predicted the flame propagation in the mixture inside a tube reasonably. In addition, the finite chemistry model predicted well the backdraft phenomena in a compartment qualitatively. The flame propagation inside the compartment, fuel and oxygen distribution and explosive fire ball behavior were well simulated with the finite chemistry model. It showed that the FDS adopted with the finite chemistry model can be an effective simulation tool for the investigation of backdraft in a compartment.

• Journal of the Korean Society of Visualization
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• v.22 no.1
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• pp.68-78
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• 2024

The stratification phenomena of still hydrogen (20%) and methane (80%) gas mixture in a vertical urban gas pipe have been investigated by simulating the flows based on a mixture model. The stratification is accompanied with the natural convection by the buoyancy force. The hydrogen volume fraction in the upper sections of the pipe increases with time but the increasing rate gets smaller due to the weaker buoyancy force. The pipe with a smaller diameter exhibits a higher peak of hydrogen concentration. The size of vortices is proportional to the pipe diameter. The slip velocity between hydrogen and methane oscillates with a large amplitude at the earlier stage of stratification and then the amplitude decreases sharply. The slip velocity decreases with the diameter, making the stratification become slower. The length of pipe does not affect the stratification since the pipe is sufficiently long relative to the size of vortices.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.16
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• pp.7359-7363
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• 2015

Background: As a result of significant progress made in treatment of many types of cancers during the last few decades, there have been an increased number of patients who do not experience mortality. We refer to these observations as cure or immune and models for survival data which include cure fraction are known as cure rate models or long-term survival models. Materials and Methods: In this study we used the data collected from 438 female patients with breast cancer registered in the Cancer Research Center in Shahid Beheshti University of Medical Sciences, Tehran, Iran. The patients had been diagnosed from 1992 to 2012 and were followed up until October 2014. We had to exclude some because of incomplete information. Phone calls were made to confirm whether the patients were still alive or not. Deaths due to breast cancer were regarded as failure. To identify clinical, pathological, and biological characteristics of patients that might have had an effect on survival of the patients we used a non-mixture cure rate model; in addition, a Weibull distribution was proposed for the survival time. Analyses were performed using STATA version 14. The significance level was set at $P{\leq}0.05$. Results: A total of 75 patients (17.1%) died due to breast cancer during the study, up to the last follow-up. Numbers of metastatic lymph nodes and histologic grade were significant factors. The cure fraction was estimated to be 58%. Conclusions: When a cure fraction is not available, the analysis will be changed to standard approaches of survival analysis; however when the data indicate that the cure fraction is available, we suggest analysis of survival data via cure models.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.2
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• pp.249-265
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• 1995

The performance of a refrigerant mixture of propane(R290)/isobutane(R600a) as a substitute for CFC12 was investigated in a domestic refrigerator with single evaporator. A thermodynamic cycle simulation indicated an increase in COP of a 1.7 to 2.4% with R-290/600a in the composition range of 0.2 to 0.6 mass fraction of R290 compared to CFC12. For the tests, two units($299{\ell}$, $465{\ell}$) were used. All refrigeration components remained the same throughout the tests, except that the length of capillary tube and amount of charge were changed for the mixture. The refrigerators were fully instrumented with more than 20 thermocouples, 2 pressure transducers, and watt/watt-hour meter for each refrigerator. 'Energy consumption test' and 'no load pulldown test' were performed under the same condition. The experimental results obtained with the same compressor indicated that R-290/600a mixture at 0.6 mass fraction of R290 showed a 3 to 5% increase in energy efficiency and a faster cooling speed compared to CFC12. The R-290/600a mixture showed a shorter compressor on-time and a lower compressor dome temperature than CFC12. In conclusion, the proposed hydrocarbon mixture seems to be an appropriate candidate to replace CFC12 without causing more environmental problems.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.4
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• pp.249-256
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• 1993

Numerical method is applied to predict the time variation behavior of flammable mixture formation in a two dimensional enclosure from the beginning of gas leak. Additionally experimental method is used to consider qualitative aspects. Characteristics of flammable mixture formation such as distribution of flow and fuel mass fraction at various locations in the enclosure are determined for the following parameters: the various locations of leak at the bottom and aspect ratio of the enclosure. In the case of gas leak with small leak velocity from the bottom of enclosure gravitational force affects the formation of flammable mixture. Aspect ratio of the enclosure also affects the formation of flammable mixture. The volume of the region of recirculating flow is dominant factor affecting the formation mixture.

• Korean Journal of Food Science and Technology
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• v.12 no.3
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• pp.209-215
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• 1980

Proteases from papaya latex were partially purified by ammonium sulfate precipitation and separated into two fractions (Fraction I and II ) by carboxymethyl cellelose column chromatography. Each fraction, mixture of the two fractions, and crude extract of the papaya latex at pH 7.0 were inactivated at the range of $60{\sim}90^{\circ}C$ and thermal properties of the enzymes were investigated. In the thermal inactivation of fraction I, the enthalpy of activation was 89.5 kJ/mol; the entropy of activation, -44.0 J/mol K; the free energy of activation, 104.6 kJ/mol; z-value, $25^{\circ}C$. For fraction II, the enthalpy of activation was 96.5 kJ,/mol; the entropy of activation, -22.0 J/mol K; the free energy of activation, 104.0 kJ/mol; z-value, $23^{\circ}C$. For the mixture of fraction I and II, the enthalpy of activation was 90.9 kJ/mol; the entropy of activation, -38.8 J/mol·K; the free energy of activation, 104.2 kJ/mol; z-value, $24.6^{\circ}C$. For crude extract, the enthalpy of activation was 113.8 kJ/mol; the entropy of activation, 22.0 J/mol·K; the free energy of activation, 106.2 kJ/mol; z-value, $23.2^{\circ}C$. It was indicated that the fraction I was more heat-stable than the fraction II and this suggested that the thermal stability of the proteases in papaya latex is probably due to the fraction I.

• Journal of Ginseng Research
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• v.9 no.2
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• pp.135-145
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• 1985

The present study was undertaken in order to elucidate the effect of ginseng butanol fraction on ethanol induced hepatic aniline hydroxylase activity in rat. Ginseng butanol fraction increased the hepatic aniline hydroxylase activity which is inhibited by ethanol addition in the enzyme assay system, whereas not shown the ginseng effect in ethanol absence condition in vitro. It was found that ginseng butanol fraction improved the affinity of aniline hydroxylase under presence of ethanol in the reaction mixture. On the contrary ginseng butanol fraction showed significant decreasing effect on aniline hydroxylase activity induced by ethanol administration. These results suggest that ginseng butanol fraction regulate the hepatic aniline hydroxylase activity which is induced by ethanol consumption.

• Progress in Superconductivity and Cryogenics
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• v.10 no.4
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• pp.38-42
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• 2008

Miniature J-T cryocooler using nitrogen or argon has been widely adopted in cooling infrared sensor for space/military application and cryosurgery. Argon or nitrogen, however, has relatively low specific cooling power compared to nitrous oxide, but the ultimate operating temperature is much lower than nitrous oxide. On the other hand, nitrous oxide has large specific cooling power, but the operating temperature is limited to its boiling point (>183K). To compromise the different characteristics of these gases, the performance of miniature J-T cryocooler using argon and nitrous oxide mixture is investigated in this paper. Three different compositions of mixture (25/75, 50/50, and 75/25 molar fraction) are blended and tested. The results are compared with the experiments of pure argon and pure nitrous oxide. The experimental results show some encouraging potentiality of mixed refrigerant J-T cryocooler. The critical clogging problem, however, was observed with argon and nitrous oxide mixture, and the lowest achievable temperature with this mixture was limited to the freezing point of nitrous oxide. The paper discusses detailed clogging process of the mixture and suggests an alternative.

• Korean Journal of Remote Sensing
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• v.22 no.6
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• pp.553-563
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• 2006

This study aims to produce land-cover maps of Korean peninsula using multi-temporal MODIS (Moderate Resolution Imaging Spectroradiometer) imagery. To solve the low spatial resolution of MODIS data and enhance classification accuracy, Linear Spectral Mixture Analysis (LSMA) was employed. LSMA allowed to determine the fraction of each surface type in a pixel and develop vegetation, soil and water fraction images. To eliminate clouds, MVC (Maximum Value Composite) was utilized for vegetation fraction and MinVC (Minimum Value Composite) for soil fraction image respectively. With these images, using ISODATA unsupervised classifier, southern part of Korean peninsula was classified to low and mid level land-cover classes. The results showed that vegetation and soil fraction images reflected phenological characteristics of Korean peninsula. Paddy fields and forest could be easily detected in spring and summer data of the entire peninsula and arable land in North Korea. Secondly, in low level land-cover classification, overall accuracy was 79.94% and Kappa value was 0.70. Classification accuracy of forest (88.12%) and paddy field (85.45%) was higher than that of barren land (60.71%) and grassland (57.14%). In midlevel classification, forest class was sub-divided into deciduous and conifers and field class was sub-divided into paddy and field classes. In mid level, overall accuracy was 82.02% and Kappa value was 0.6986. Classification accuracy of deciduous (86.96%) and paddy (85.38%) were higher than that of conifers (62.50%) and field (77.08%).