• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.672-678
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• 2002

Oxidative stress contributes to cellular injury following clinical and experimental ischemia/reperfusion scenarios. Oxidative injury can induce cellular and nuclear damages that result in apoptotic cell death. We tested the hypothesis that the catechin flavonoid of (-)epigallocatechin gallate, a green tea polyphenol, inhibits hydrogen peroxide ($H_2O$$_2$)-induced apoptosis in human umbilical vein endothelial cells. The effect of apigenin, a flavone found in citrus fruits, on apoptosis parameters was also examined. A 30 min pulse treatment with 0.25 mM $H_2O$$_2$ decreased endothelial cell viability within 24 hrs by > 30% ; this was associated with nuclear condensation and biochemical DNA damage consistent with programmed cell death. In the 0.25 mM $H_2O$$_2$apoptosis model, 50${\mu}{\textrm}{m}$ (-)epigallocatechin gallate markedly increased cell viability with a reduction in the nuclear condensation and DNA fragmentation. In contrast, equimicromolar apigenin increased cell loss with intense DNA laddering, positive nick-end labeling and Hoechst 33258 staining. Thus, polyphenolic (-)epigallocatechin gallate, but not apigenin flavone, qualify as an antioxidant in apoptosis models caused by oxidative stress. Further work is necessary for elucidating the anti-apoptotic mechanisms of polyphenolic catechins.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.6
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• pp.805-811
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• 2016

This study was conducted to investigate the protective effects of water extract from Crassostrea gigas (CGW) against ethanol-induced hepatic toxicity in rats. Seventy-two male Wistar rats (6-week-old) were divided into six groups of 12 animals each: control group (1 mL saline/d), ethanol-treated group, positive control group (ethanol+Hovenia dulcis Thunb extract), CGWL group (ethanol+low dosage of CGW), CGWM group (ethanol+medium dosage of CGW), and CGWH group (ethanol+high dosage of CGW). All groups except the control group received ethanol (40% ethanol 5 g/kg) orally. CGW administration with ethanol resulted in prevention of ethanol-induced hepatotoxicity by increasing levels of serum alanine aminotransferase and ${\gamma}-glutamyltransferase$. CGW supplementation significantly reduced formation of malonaldehyde and inhibited reduction of hepatic glutathione and peroxidase levels, as compared with the ethanol-administration group. Further, CGW suppressed expression of CYP2E1, which was elevated by ethanol administration. Consequently, our results indicate that Crassostrea gigas may exert hepatoprotective effects against alcohol-induced hepatocyte injury by intensifying the anti-oxidative defense system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.6
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• pp.903-910
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• 2016

In this study, the expression level of estrogen receptor in an ovariectomized rat model was effectively enhanced by MS-10, Cirsium japonicum and Thymus vulgaris extract complex, in a reversible manner. MS-10 plays a positive role in enhancing estrogen activity at low concentrations, leading to improved women's health. In order to determine whether or not MS-10 improves menopausal symptoms clinically, a randomized, double-blinded, and placebo-controlled clinical study was carried out on 62 middle-aged women treated with 500 mg of MS-10 or placebo daily for 12 weeks. Clinical menopausal symptoms were evaluated by Kupperman's index (KI) detecting various menopausal symptoms, including hot flushes, parenthesis, insomnia, nervousness, melancholia, dizziness, fatigue, rheumatic pain, palpitations, formication, and headaches. Total KI score decreased significantly by about 18% upon ingestion of MS-10. Colpoxerosis, a main symptom of menopause, was significantly reduced by about 21% upon ingestion of MS-10 in contrast to placebo. In addition, reduction of insulin-like growth factor-1 with age was improved by over 10% upon ingestion of MS-10, whereas there were no significant difference with placebo. No side effects appeared after treatment with MS-10. Thus, MS-10 can be suggested as a plausible natural substance for improving women's health.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.872-877
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• 2002

Two experiments were conducted to determine the effects of reducing particle size of corn from 1,000 to 500 ${\mu}m$ in simple and complex diets for nursery pigs and broiler chicks. In Exp 1., 192 nursery pigs were used in a 24 d growth assay. Treatments were: 1) 1,000 ${\mu}m$ corn in a simple diet; 2) 500 ${\mu}m$ corn in a simple diet; 3) 1,000 ${\mu}m$ corn in a complex diet; and 4) 500 ${\mu}m$ corn in a complex diet. Overall, pigs fed complex diets had 9% greater ADG (p<0.005) and 5% greater gain/feed (p<0.01) compared to pigs fed simple diets. Also, pigs fed the 500 ${\mu}m$ treatments had 3% better overall gain/feed than those fed the 1,000 ${\mu}m$ treatments (p<0.007). At d 9, apparent digestibilities of DM, N and GE were greater for complex diets and diets with smaller particle size (p<0.02). At d 23, there were no differences in nutrient digestibility resulting from diet complexity, but pigs fed diets with corn ground to 500 ${\mu}m$ had greater digestibility of DM (p<0.02) and GE (p<0.003) than pigs fed diets with corn ground to 1,000 ${\mu}m$. A second experiment was designed to determine if four days old broiler chicks were an acceptable model for predicting the effects of feed processing procedures on nursery pigs. Chicks fed complex diets had 3% greater gain/feed than chicks fed simple diets (p<0.001). Rate of gain and feed intake were improved by 3 and 2%, respectively, for chicks fed crumbled diets (p<0.03). However, there were several significant interactions among the main effects. For instance, crumbling did not affect gain/feed in chicks fed complex diets, but rate of gain and feed intake were increased by 7 and 6%, respectively, when simple diets were crumbled (diet complexity${\times}$diet form, p<0.001). Also, gain/feed of chicks was improved by 3% when particle size was reduced in meal diets, but not affected in chicks fed crumbles (diet form${\times}$particle size, p<0.005). Thus, our data suggested that reduction of particle size of corn was important for simple and complex diets and that a complex diet with 1,000 ${\mu}m$ corn gave no better performance than a simple diet with 500 ${\mu}m$ corn.

• Journal of Nutrition and Health
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• v.39 no.6
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• pp.520-528
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• 2006

Free amino acids in epidermis function as a major component of Natural Moisturizing Factor (NMF), which maintains the optimal level of water in skin even at the low humidity. In fact, the depletion of free amino acids is reported in the epidermis of atopic dermatitis, the skin condition involving dryness. As an effort searching the dietary source for improving the level of water and free amino acid in epidermis, the dietary effects of silk protein, sericin (S) and fibroin (F) on trans epidermal water loss (TEWL), and plasma and epidermal levels of free amino acids were compared in this study. Thirty of male NC/Nga mice, an animal model of atopic dermatitis, were divided into three groups: group CA as an atopic control with control diet, group S: 1% sericin diet and group F: 1% fibroin diet. Ten of male BALB/c mice were served as group C (control group) with control diet. All mice were fed on diet and water ad libitum for 10weeks. Dry skin condition was established in group CA as TEWL was increased (148.7% of group C). In parallel, epidermal level of glutamate, one of major amino acids functioning as NMF, was dramatically decreased and epidermal levels of methionine and alanine were inversely elevated. Dietary supplementation of sericin (group S) reduced TEWL at the similar level with group C and increased epidermal levels of glutamate as well as serine and glycine, the other major amino acids as NMF. Despite a marked decrease of methionine and alanine, the reduction of TEWL and epidermal levels of glutamate, serine and glycine of group F were less than of group S. Furthermore, in contrast to similar levels of other free amino acids in plasma and epidermis of group S and group C, plasma and epidermal levels of other free amino acids, specifically phenylalanine, isoleucine, cysteine and tyrosine in epidermis of group F, were significantly higher than of group C. Together, our data demonstrate that dietary supplementation of sericin is more effective at improving dry skin condition that paralleled with the normalization of free amino acids in plasma and epidermis of NC/Nga mice.

• Journal of the Korean Institute of Navigation
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• v.19 no.2
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• pp.77-97
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• 1995

The protection of the marine environment is one of the main international legal problems in recent years. In parallel with the industrial development, a great quantity of chemical materials were used and in consequence, mass transportation of oil and other dangerous materials was required on the one hand, and discharge of industrial wasters drew also the attention on the other hand. Furthermore, oil tankers accidents, mass use of nuclear materials, sea-bed exploration and exploitation stimulated further deep human concern on the marine environment. The expansion of international concern to new and more dangerous sources of marine pollution regarded more strict and legal control on the Oil Tanker(DWT 95, 000tons, Cb=0.805) model. Calculation results are compared to the international, especially regional level. In particular, this study is concerned with the preservation of the Northeast Asian Seas surrounded by Japan, the Russian Far East, South Korea, North Korea, China and Taiwan. These adjacent countries must intensify cooperation regarding the prevention, reduction and control of the contamination of the sea. And this cooperation between the States concerned should, as much as possible, be aimed at maximizing the effectiveness of measures to prevent or abate transboundary environmental pollution. To achieve this purpose, States concerned should be imposed upon duties such as duty to assess the environmental impact, duty to inform, duty to consult and duty to assist on the basis of general principle of international law, international customary law and other various resolutions of international bodies. Depending on the nature and extent of actual or potential transboundary pollution with the use of a natural resource or the environment in general the establishment of some form of institutionalized cooperation between the States concerned may become useful or indispensable. The functions of this Organization are, inter alia, to keep the implementation of the Convention and the protocals under continuous observation, to make recommendations on regional or sub-regional rules and standards to be elaborated and on measures to be taken by the Contracting Parties, to be notified of any grave and imminent danger from pollution or threat of pollution by the Contracting Parties and to promote in close cooperation with appropriate governmental bodies additional measures to protect the marine environment of the Northeast Asian Seas, and so on. Above mentioned countries, first of all, are located within the Northeast Asian Seas geographically and, therefore, take responsibilities of preserving the clean sea against marine interferences regardless of any difference of the social, political and economic systems. They must be followed under the UNCLOS and other marine conventions. Under the present circumstances, Northeast Asian Seas will become dead seas in case that there is no instant and prompt action against pollution. Hence we have an absolute obligation to promote the development of the mandatory international environmental law, which in turn can faciliate more effective implementation of the regional cooperation by the neighbouring states within this area.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.590-597
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• 1985

A recursive geometric adaptive control method to compensate for machining straightness error in the finished surface due to tool deflection and guideway error generated by end milling process is developed. The relationship between the tool deflection and the feedrate is modeled by a modified Taylor's tool life equation. Without a priori knowledge on the variations off cutting parameters, time varying parameters are then estimated by an exponentially windowed recursive least squares method with only post-process measurements of the straightness error. The location error is controlled by shifting the milling bed in the direction perpendicular to the finished surface and adding a certain amount of feedrate with respect to the tool deflection model before cutting. The waviness error is compensated by adjusting the feedrate during machining. Experimental results show that location error is controlled within a range of fixturing error of the bed on the guideway and that about 60% reduction in the waviness error can be achieved within a few steps of parameter adaption under wide operating ranges of cutting conditions even if the parameters do not converge to fixed values.

• Progress in Medical Physics
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• v.10 no.1
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• pp.23-32
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• 1999

Combined MRI and Relaxogram approach was introduced as a very useful tool for fat study. The phantoms simulating homogeneous mixture of fat and non-fat environments were measured with spin echo pulse sequence on a 0.15 T whole body imager. From 45 scans, the Tl values were obtained by fitting the data to continuous distribution (CONTIN) of relaxation time. This relaxogram gives broad distributions of relaxation time, which are characterized by a number of peaks with characteristic T1 values. Two distinct peaks in relaxogram were observed and identified as signals from com oil and gelatin gel. This model system can be served as simulating the distribution of fat in muscle. Also the relative ratio of two components, which is proportional to the area under the peak, is estimated and compared to nominal values. Based on the good agreement between two predictions, the values from our proposed method agreed with nominal values within $\pm$7 % error. The effects of different concentration of contrast agent and different region of interest are presented. To optimize total scan times, the minimum required data points and so further reduction in total scan times are discussed.

• Investigative Magnetic Resonance Imaging
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• v.6 no.2
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• pp.158-165
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• 2002

Purpose : To evaluate the effect of Gd-DTPA on signal intensity of diffusion-weighted magnetic resonance(MR) image and apparent diffuse coefficient (ADC) in dog brain with hype racute stroke. Materials and methods : Experimental canine model of hyperacute cerebral infarction was made by selective intraarterial embolization with particulate embolic material. Diffusion-weighted MR imaging was performed in five dogs at 1 hour after the embolization of internal carotid artery. After intravenous bolus injection of Gd- DTPA, additional 11 diffusion-weighted MR images were serially obtained from 2 minutes to 90 minutes after injection in each dog. The author evaluated findings of hyperacute cerebral infarction on diffusion-weighted MR imaging, and calculated mean signal intensity and mean ADC in infarcted region and contralateral normal region. Statistical analysis of mean signal intensity, mean ADC and contrast-noise ratio before and after Gd-DTPA injection was performed. Results : Hyperacute cerebral infarction developed in all five dogs on diffusion-weighted MR images obtained 1 hour after embolization. The area of hyperacute infarction had steady increase in signal intensity on diffusion-weighted MR image and decrease in ADC. In normal perfusion area, decrease in signal intensity was observed at 2 minutes the Gd-DTPA injection, whereas ADC did not changed. Conclusion : Intravenous injection of Gd-DTPA had no influence on ADC in both hyperacute infarction and normally perfused are a, but caused initial transient signal reduction in normally perfused area on diffusion-weighted MR image due to susceptibility effect of Gd-DTPA. It is important to calculate ADC in evaluating the effect of diffusion after injection of Gd-DTPA.

• Land and Housing Review
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• v.9 no.2
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• pp.41-50
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• 2018

The purpose of this study is to review the U.S. renewable energy policies implemented by the federal government and the state governments to investigate potential barriers of renewable energy expansion and to develop policy implications for the successful renewable energy policy making in Korea. Recently, the restructuring in the energy supply chain has been being a new trend in many countries that shows a transition from traditional fossil fuels to sustainable renewable energy sources. The United States has enforced effective renewable energy policies (i.e., regulatory policies, financial incentives), which have led to the exploding growth of renewable energy facilities and productions over the last ten years. For example, many state governments in the U.S. are implementing Renewable Portfolio Standard (RPS) policies that require increased energy supply from renewable energy sources (i.e., solar, wind and geothermal). These RPS policies are expected to account for at least 10-50 percent of total electricity production in the next fifteen years. As part of results, in the recent three years, renewable energy in the U.S provided over 50 percent of total new power generation constructions. On the other hand, Korea initiated to develop climate change policies in 2008 for the Green Growth Policy that set up a target reduction of national Greenhouse Gas (GHG) emissions up to 37 percent by 2025. However, statistical data for accumulated renewable energy capacity refer that Korea is still in its early stage that contribute to only 7 percent of the total electricity production capacity and of which hydroelectric power occupied most of the production. Thus, new administration in Korea announced a new renewable energy policy (Renewable Energy 3020 Plan) in 2017 that will require over 95 percent of the total new generations as renewable energy facilities to achieve up to 20 percent of the total electricity production from renewable energy sources by 2030. However, to date, there have not been enough studies to figure out the barriers of the current policy environment and to develop implications about renewable energy policies to support the government plan in Korea. Therefore, this study reviewed the U.S. renewable energy policies compared with Korean policies that could show model cases to introduce related policies and to develop improved incentives to rapidly spread out renewable energy facilities in Korea.