• 설비공학논문집
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• 제14권12호
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• pp.1078-1083
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• 2002

The objectives of this paper are to measure the concentration of $H_2$O/LiBr solution by measuring the electrical conductivity and to study the effect of the solution temperature and the concentration on the electrical conductivity of the solution. The solution temperature ranges $20^{\circ},\;40^{\circ},\;and\; 60^{\circ}$ for a fixed concentration during the experiment. The valid ranges of the concentration are two regions, low concentration region (1~20% of LiBr) and high concentration region (55~66% of LiBr). The results show that the conductivity of the solution increases linearly with increasing the solution temperature while it increases without creasing the concentration lower than about 35% of LiBr and decreases with increasing the concentration higher than 35%. This paper proposes experimental correlations for the concentration as functions of the solution temperature and the concentration with error band of $\pm7$% for the low concentration region and $\pm1$% for the high concentration region, respectively. The experimental correlation can be practically used in the on-line measurement without any sampling of solution from the closed system.

• 한국식품영양과학회지
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• 제29권5호
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• pp.893-899
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• 2000

Oil emulsion에 느릅나무 근피(한국산, 중국산), 수피(한국산) 각 추출물 0.05% 첨가에 의한 항산화 작용의 실험 결과는 다음과 같다. 활성 산소종, 금속이온 참가에 따른 지방 산화 억제능은 근피, 수피 각 용매 추출물의 $H_2O_2,-OH,\;KO_2$에 대한 포집능은 모두 우수하여 높은 항산화 효과를 나타내었으며, 각 추출물과 $Fe^{2+}$ ion과 $Cu^{2+}$ ion도 강한 활성 유리 라디칼 포집능으로 우수한 항산화 효과를 보였다. 지방 산화를 촉진하는 nonheme iron 함량에서 $Fe^{2+}$ 함량과 total iron 함량은 근피(중국산) 에탄올, 메탄올 추출물이 가장 높은 함량을 나타내었고, 한국산 근피, 수피의 에탄올, 메탄올 그리고 부탄올 추출물군에서 80% 이상의 높은 활성을 보였고, 물 추출물군의 경우 20~55%의 범위로 낮은 효과를 보였다. SOD 유사활성은 근피(중국산) 부탄올 추출물, 수피(한국산) 물 추출물에서 가장 높은 활성능을 보였다. 아질산염 소거능의 경우도 근피, 수피 에탄올, 메탄올 그리고 부탄올 추출물군 모두 우수한 소거능을 보였고, 특히 pH 1.2에서는 가장 높은 아질산염 소거능을 보였으며, pH 6.0으로 갈수록 급격히 감소하였다.

• Nutrition Research and Practice
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• 제13권4호
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• pp.279-285
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• 2019

BACKGROUND/OBJECTIVES: Excessive production of reactive oxygen species (ROS) such as hydroxyl (${\cdot}OH$), nitric oxide (NO), and hydrogen peroxide ($H_2O_2$) is reported to induce oxidative stress. ROS generated by oxidative stress can potentially damage glial cells in the nervous system. Cordyceps militaris (CM), a kind of natural herb widely found in East Asia. In this study, we investigated the free radical scavenging activity of the CM extract and its neuroprotective effects in $H_2O_2$-induced C6 glial cells. MATERIALS/METHODS: The ethanol extract of CM ($100-1,000{\mu}g/mL$) was used to measure DPPH, ${\cdot}OH$, and NO radical scavenging activities. In addition, hydrogen peroxide ($H_2O_2$)-induced C6 glial cells were treated with CM at $0.5-2.5{\mu}g/mL$ for measurement of cell viability, ROS production, and protein expression resulting from oxidative stress. RESULTS: The CM extract showed high scavenging activities against DPPH, ${\cdot}OH$, and NO radicals at concentration of $1,000{\mu}g/mL$. Treatment of CM with $H_2O_2$-induced oxidative stress in C6 glial cells significantly increased cell viability, and decreased ROS production. Cyclooxygenase-2 and inducible nitric oxide synthase protein expression was down-regulated in CM-treated groups. In addition, the protein expression level of phospho-p38 mitogen-activated protein kinase (p-p38 MAPK), phospho-c-Jun N-terminal kinase (p-JNK), and phospho-extracellular regulated protein kinases (p-ERK) in $H_2O_2$-induced C6 glial cells was down-regulated upon CM administration. CONCLUSION: CM exhibited radical scavenging activity and protective effect against $H_2O_2$ as indicated by the increased cell viability, decreased ROS production, down-regulation of inflammation-related proteins as well as p-p38, p-JNK, and p-ERK protein levels. Therefore, we suggest that CM could play the protective role from oxidative stress in glial cells.

• 대한본초학회지
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• 제28권4호
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• pp.57-62
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• 2013

Objectives : Lonicerae Japonicae Flos (LJF) has been shown anti-oxidant, anti-inflammatory, anti-viral, anti-rheumatoid properties. However, it is still largely unknown whether LJF inhibits skin injury against oxidative stress in human keratinocyte, HaCaT cells. The purpose of this study was to evaluate the protective effects of LJF against hydrogen peroxide($H_2O_2$)-induced oxidative stress in human keratinocytes, HaCaT cells. Methods : To evaluate out the protective effects of LJF on oxidative injury in HaCaT cells, an oxidative stress model of HaCaT cells was established under a suitable concentration (500 ${\mu}M$) hydrogen peroxide. HaCaT keratinocyte cells were pre-treated with LJF (0.1, 0.25 or 0.5 mg/ml), and then stimulated with $H_2O_2$. Then, the cells were harvested to measure the cell viability, DNA damage, and release of reactive oxygen species (ROS). Results : LJF (0.1, 0.25 or 0.5 mg/ml) itself did not show any significant toxicity in HaCaT cells. The treatment of $H_2O_2$ caused the oxidative stress, leading to the cell death, and DNA injury. However, pretreatment with LJF reduced cell death, and DNA injury. The stimulation of $H_2O_2$ on HaCaT cells resulted in excessive release of ROS, which is the main factor of oxidative stress. The excessive release of ROS was inhibited by LJF treatment significantly. Conclusions : These results could suggest that LJF exhibited the protective effects of HaCaT cells against $H_2O_2$-induced oxidative stress by inhibiting ROS release. It could be explained that LJF inhibit skin damages against oxidative stress. Thus, LJF would be useful for the development of drug or cosmetics treating skin troubles.

• Journal of Advanced Marine Engineering and Technology
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• 제23권2호
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• pp.192-200
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• 1999

This paper describes experimental investigations of helium-air exchange flow through parti-tioned opening. Such exchange flow may occur following rupture accident of stand pipe in high temperature gas cooled reactor. A test vessel with a opening on top of test cylinder is used for experiments. An estimation method of mass increment is developed and applied to measure the exchange flow rate. A technique of flow visualization by Mach-Zehnder interferometer is provided to recognize the exchange flows. Flow measurements are made with partitioned opening for parti-tion rations $H_p/H_1$ in the range 0 to 1 where $H_p$ and $H_1$ are partition length and height of the open-ing respecticely. In the case of $H_p/H_1$ of 0 flow passages of upward flow of the helium and down-ward flow of the air within the opening are unseparated (bidirectional) and the two flows interact exchange flow rate is minimum through range of the partition ratios, Two flow zones i.e. separat-ed(unidirectional)flow zone and unseparated(bidirectional) flow zone exist with increasing the partition. length, The exchange flow rate increases with increasing the separated flow zone. It is found that a maximum exchange flow rate exists at $H_p/H_1$ of 1. As a result fo comparison of the exchange flow rates by changing the partition ration the fluids interaction in the unseparated zone is found to be an important factor on the helium-air exchange flow rate.

• 보존과학연구
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• 통권20호
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• pp.49-64
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• 1999

According to damage of papers by the chemical cause, papers become to acidify. Among the 3 kinds of method measuring the acidity of paper, one was nondestructive method measuring the surface of the paper by flat type electrode and the others were destructive methods measuring directly by cold water extract method and hot water extract method. In case of the cellulolytic cultural properties, the latter methods were not applied because those methods must bedissociated papers. To measure the paper acidity nondestructively, we investigated the correlation of the nondestructive method and the destructive methods. The conclusions are as follows. 1) In the relationship of the cold water extract method and the hot water extract method, It was indicated that the pH measured by the hot water extract method was high quality printing paper 0.08, rough printing paper 0.13, and Korean paper 0.29 higher than that by the cold water extract method.2) In the relationship of the cold water extract method and the surface measurement method, It showed that the pH value measured by the cold water extract method was high quality printing paper 1.86, rough printing paper 0.80,and Korean paper 0.58 higher than value that by the surface measurement.3) In the relationship of the hot water extract method and the surface measurement method, It showed that the pH value measured by the hot ABSTRACT water extract method was high quality printing paper 1.78, rough printing paper 0.66, and Korean paper 0.29 higher than that by the surface measurement. From the above-mentioned results, the pH value measured by the surface measurement was need to high about 1.78∼1.86 in high quality printing paper, 0.66-0.80 in rough printing paper, and 0.29∼0.58 in Korean paper and the surface measurement with flat type electrode was very available to measure the acidity of Korean papers actually.

• Applied Biological Chemistry
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• 제41권4호
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• pp.228-234
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• 1998

An adaptive measure of photosynthetic cells to a condition identified with a reduction of cellular energy charge, caused by water deficit-induced impairment of photosynthetic ATP production, was investigated using hydroponically cultured rice seedlings. Water stress treatment of the seedlings resulted in a marked decrease in cellular ATP level, a significant increase in the content of NAD(H) and concurrent decrease in that of NADP(H) in shoots, which accompanied a decrease in the activity of NAD kinase (EC 2.7.1.23) that specifically converts NAD(H) to NADP(H). The decline in the enzyme activity was particularly evident in the $Ca^{2+}/calmodulin-dependent$ kinase, the major form of NAD kinase in plants, whereas the level of active calmodulin remained unchanged during water deficit. The ratio of $NADP^+$ to NADPH was maintained nearly constant and no increases were seen in the level of $H_2O_2$ and the activities of $superoxide/H_2O_2-detoxifying$ enzymes in shoots stress-treated for two days. Based on these results, it may be suggested that rice plants take a strategy to cope with an adverse situation of limited photophosphorylation created by water deficit in that cells facilitate ATP production through glycolysis and oxidative phosphorylation; in doing so, rice cells suppress NAD kinase activity, consequently up-sizing the NAD(H) pool at the expense of the NADP(H) pool. Several parameters associated with the stress symptoms are also of implicative that there is no overproduction of superoxide radical or the related active oxygen at least in rice seedlings.

• Communications for Statistical Applications and Methods
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• 제2권1호
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• pp.112-121
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• 1995

Let $p_1$ and $p_2$ be the proportions of two populations. To test the hypothesis $H_0 : p_1 = p_2$, we usually use the $x^2$ statistic, the large sample binomial statistic Z, and the Generalized Likelihood Ratio statistic-2log $\lambda$developed based on different mathematical rationale, respectively. Since testing the above hypothesis is equivalent to testing whether two populations follow the common Bernoulli distribution, one may also test the hypothesis by comparing 1 with the ratio of each density estimate and the hypothesized common density estimate, called comparison density, which was devised by Parzen(1988). We show that the above traditional test statistics ate actually estimating the measure of distance between the true densities and the common density under $H_0$ by representing them with the comparison density.

• 대한핵의학회지
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• 제27권2호
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• pp.248-255
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• 1993

To Assessment of the quantified renal uptake rates in every $^{99m}Tc$-DMSA scan tests of patients is actually difficult because of time consumption and complicated calculations required to measure the correct dose of the infused radionulide and radiation decay, the adjustment for the depth of kidney and the subtraction of background count. We've formulated two regression models for the quantified renal uptake rates[I] from the simple renal uptake rates[H] with a square shaped ROI (Region-Of-Interest) in 25 cases (Group 1) and with a kidney shaped ROI in 37 cases (Group 2), respectively. The regression model for the Group 1 was $[I]_1$=0.885 $[H]_1$-4.575 (P<0.005), and for the Group 2 was $[I]_2$=0.591 $[H]_2$-2.105 (p<0.005). The formal charts were clinically convenient to evaluate the individual renal functions in patients with $^{99m}Tc$-DMSA renal scan.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2007년도 춘계학술대회 학술발표 논문집 제17권 제1호
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• pp.209-212
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• 2007

Non-additive measures and their corresponding Choquet integrals are very useful tools which are used in both insurance and financial markets. In both markets, it is important to to update prices to account for additional information. The update price is represented by the Choquet integral with respect to the conditioned non-additive measure. In this paper, we consider a price functional H on interval-valued risks defined by interval-valued Choquet integral with respect to a non-additive measure. In particular, we prove that if an interval-valued pricing functional H satisfies the properties of monotonicity, comonotonic additivity, and continuity, then there exists an two non-additive measures ${\mu}_1,\;{\mu}_2$ such that it is represented by interval-valued choquet integral on interval-valued risks.