• Journal of the Korean Society of Combustion
• /
• v.21 no.3
• /
• pp.1-6
• /
• 2016

The effect of applied electric fields on jet flow instability was investigated experimentally by varying the direct current (DC) voltage and the alternating current (AC) frequency and voltage applied to a jet nozzle. We aimed to elucidate the origin of the occurrence of twin-lifted jet flames in laminar jet flow configuration, which occur when AC electric fields are applied. The results indicate that a twin-lifted jet flames originates from cold jet instability, caused by interactions between negative ions in the jet flow via electron attachment as $O_2+e{\rightarrow}O_2{^-}$ when AC electric fields are applied. This was confirmed by experiments in which a variety of gaseous jets were ejected from a nozzle to which DC voltages and AC frequencies and voltages were applied, with ambient air between two deflection plates connected to a DC power source. Experiments in which jet flows of several gases were ejected from a nozzle and AC electric fields were applied in coflow-nitrogen provided further evidence. The flow instability occurred only for oxygen and air jets. Additionally, jet instability occurred when the applied frequency was less than 80 Hz, corresponding to the characteristic collision response time. The effect of AC electric fields on the overall structure of the jet flows is also reported. Based on these results, we propose a mechanism to reduce jet flow instability when AC electric fields are applied to the nozzle.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.23 no.3
• /
• pp.554-561
• /
• 2009

Soyangin-Hyeongbangpaedok-san(SHBPDS) is a herbal formula used for the common cold or upper respiratory illness. In order to investigate the effect of SHBPDS, mice were orally administered with SHBPDS alcohol extract for 7 days followed by intravenous anti-CD3 injection. In addition, splenocytes and CD4 T cells were cultured with SHBPDS in response to anti-CD3 in vitro and cytokines and transcription factors were evaluated. In vivo treatment with SHBPDS significantly augmented the expressions of the percentage of CD4 T cells and CD 69, an indicator of early T cell activation. Serum levels of IL-4 were significantly increased but those of IFN-${\gamma}$ and IL-2 did not reach statistical significance. The expressions of IFN-${\gamma}$ and T-bet mRNA were significantly downregulated in SHBPDS treated mice while those of IL-4 and C-Maf were significantly upregulated. In vitro stimulation of splenocytes and CD4 T cells by SHBPDS resulted in a reduction in IFN-${\gamma}$ secretion and STAT4 activity. The IL-4 releases from both cells were slightly reduced, but STAT6 activity was rather increased. In conclusion, SHBPDS exerted an inhibition in the expression of IFN-${\gamma}$, T-bet and STAT4 while IL-4, C-Maf and STAT6 were increased. Further studies are required to examine its pharmacological effects using more appropriate animal experiments.

• Journal of Plant Biotechnology
• /
• v.29 no.2
• /
• pp.99-104
• /
• 2002

Suppression subtractive hybridization (SSH) was used to isolate wound-induced cDNAs from wounded soybean. One of low-temperature-inducible cDNA, slti182 showed high homology with genes encoding 1-asparaginase. The full length cDNA of slti182, deginated GmASP1, is 1258 bp long and contains an open reading frame consisted of 326 amino acids. CmASP1 protein showed the highest identity (84%) with putative asparaginase from A. thaliana (AB012247), but it showed only 55% identity with another isoform of A. tathaliana (Z34884). The expression of GmASP1 during low temperature stress started to increase 3 hours after treatment, reached the maximum at 6 hour, and then decreased to the initial level at 48 hours. The amount of GmASP1 transcripts increased again when low-temperature-treated plants were transferred to room temperature, The present study suggests that GmASP1 may function to accelerate the protein synthesis which is important in the early response to low temperature.

• Journal of Plant Biotechnology
• /
• v.44 no.3
• /
• pp.296-302
• /
• 2017

Rice (Oryza sativa) cultivars show an impairment of growth and development in response to abiotic stresses such as drought, salinity, heat and cold at the early seedling stage. The tolerance to heat stress in plants has been genetically modulated by the overexpression of heat shock transcription factor genes or proteins. In addition to a high temperature-tolerance that has also been altered by elevating levels of osmolytes, increasing levels of cell detoxification enzymes and through altering membrane fluidity. To examine the heat tolerance in transgenic rice plants, three OsOPT10 overexpressing lines were characterized through a physiological analysis, which examined factors such as the electrolyte leakage (EL), soluble sugar and proline contents. We further functionally characterized the OsOPT10 gene and found that heat induced the expression of OsOPT10 and P5CS gene related proline biosynthesis. It has been suggested that the expression of OsOPT10 led to elevated heat tolerance in transgenic lines.

• Journal of the Korean Society of Food Culture
• /
• v.5 no.3
• /
• pp.331-347
• /
• 1990

This study was designed under the purpose to analyze the Korean Traditional Folk Remedies on food, to submit the basic statistical data, and to utilize them by examining how much they know about the Korean Traditional Folk Remedies and also by examining how frequently they used them. The sample was consisted of 312 housewives living in Daegu, Kyungsan city and Kyungsan-eup, the survey was made by use of questionaires from July 15 to August 1 1989. The results are as follows 1. Analysis of Folk Remedical Contents 1) The method of the Folk Remedies used in this area was mainly food, which can be easily found around their house and easy to use, it was possible to apply scientific principles in some cases. 2) The major popular method was shown to feed boiled barley or brown rice which are known as the Folk Remedy for Diabetes. 3) The ANOVA of variable shows the significant influence on each object which age, religion, the level of education, job, monthly income, and the area except family formation. 2. The Frequency of Folk Remedies and additional analysis 1) The most frequently used Folk Remedy was Arterio-sclerosis(1.44), which is followed by the loss of Eyesight(1.40), Hang over(1.28), Couth(1.27), Cold(1.26) etc. 2) In the analysis of Pearson Correlation between frequencies of Folk Remedies used, and demographic variables such as age(p<.05), the monthly income(p<.01), in that area, total number of response items showed a positive correlation. 3. The source to learn about Folk Remedy. 1) It is acknoledged that they are mostly instructed by their forefathers, friends, neighbors, professional textbooks, mass communications, herb doctors, other medical sources or education at school etc. 2) The ANOVA of Variables shows the big differences between each group by age. Based on the above findings, the following suggestions are made ; Most of Korean Traditional Folk Remedies are recognized scientific and reasonable which are based on the scientific research and herb medicine therefore it should be made good use of for our life in good health additionally. I hereby insist that the importance of our Folk Remedies should be reviewed and focused for maintenance our health.

• Health Policy and Management
• /
• v.16 no.1
• /
• pp.1-16
• /
• 2006

Recently, there has been prevailing of the combined utilization (CU) with herbs and prescribed drugs in medical therapies in the world. But the information about frequency, efficacy and safety of this CU has not well known in Korea, yet. This study aimed to identify the status of CU by Koreans, and to inquire which side effects of CU represent to those people. A self-completed questionnaire survey was performed through each health examination center in twenty general hospitals and one oriental hospital. Of the initial 2,100 health examinees, 1,851 were participated in this survey, resulting in a response rate of 88.1%. The proportion of CD was 26.3%. The most commonly mentioned reason of CD was 'to promote general health and well-being' (17l persons, 35.5%). The main route of taking CD was self-purchase at drugstore or at herbs market, followed by the prescription of (oriental)physicians. 33.0% (151 persons) of those who took the CD rated it as effective. 93 respondents (19.8%) were experienced several adverse effects including nausea, fatigue, and dizziness. The growing simultaneous use of herbal products and pharmaceutical drugs by Korean consumers may be continuously increased the risk of herb-drug interactions. The medical professionals should be provided with comprehensive and up-to-date information about potential benefits and risks of herbs and prescribed drugs. In the future studies it may be recommended to deal common cold, health promotion, indigestion, headache, and hypertension for the effect and safety of the CD by well-organized prospective study design.

• Journal of the East Asian Society of Dietary Life
• /
• v.18 no.1
• /
• pp.111-126
• /
• 2008

The purpose of this study was to examine the dietary habits and nutrient intakes of school-aged children participating in extracurricular classes, to with regards to class schedule. Three-hundred and two students from Seoul were selected and classified into two groups. One group attended extracurricular classes less than 12.43 hours per week, which was determined as the average number of hours per week(AELT, n=147). The other group attended extracurricular classes more than 12.43 hours per week(AEMT, n=155). The average student age in both the AELT and AEMT groups was 11.9 years, respectively. In terms of height and weight, there were no significant differences between the two groups. AELT received significantly more hours of sleep than AEMT(p<0.01), and there were significantly more responses with regard to lack of sleep in the AEMT group than in the AELT group(p<0.05). In a survey on 17 clinical symptoms regarding health, the AEMT group had significantly higher response rates than the AELT group in the following sections: no appetite (p<0.001), dizziness(p<0.001), headache(p<0.01), tiredness(p<0.01), cold symptoms(p<0.05), and sore eyes(p<0.05). Meal time irregularity was significantly higher than AEMT than in AELT(p<0.05). Approximately 50% of the subjects were picky eaters, and 40% and 20% skipped breakfast or dinner, respectively. The average energy intakes for AELT and AEMT were 2122.2 kcal and 2061.5 kcal, respectively, and there was no significant difference between the two groups. AEMT consumed significantly lower quantities of protein, animal fat, vitamin $B_6$, calcium, and phosphorus(each p<0.05) as compared to the AELT group. Beverage intake was significantly higher in AEMT than AELT(p<0.05). The number of hours in extracurricular classes showed a significant negative correlation with the intakes of protein, animal protein, animal fat, vitamin $B_6$, folate, calcium, plant calcium and phosphorus(each p<0.05). The number of hours in extracurricular classes also showed a significant negative correlation with soy foods intake(p<0.05). These results suggest that continuous and systematic nutritional education should be performed in order to prevent and improve the unbalanced diets and problematic of dietary habits that may result in students due to attendance in extracurricular classes.

• Food Science and Biotechnology
• /
• v.15 no.1
• /
• pp.63-69
• /
• 2006

The primary objective of this study is to determine whether a diet supplemented with brown rice koji (BRK) results in a reduced stress response in rats and mice. BRK, which has been suggested as a candidate for use as a stress- and fatigue-fighting supplement, was compared with red ginseng extract (RG) for its stress-reducing potential. The animals in this study were divided into no-stress, stress, RG, and BRK groups of 8 to 10 animals each. Stress was induced by means of immobilization (being restrained in plastic tubes for 30 min and electroshock (0.5 mA in mice or 2 mA in rats for 5 min). The no-stress group was not exposed to stress. Rats in the RG group received oral doses of 200 mg RG extract/kg body weight daily. The BRK group was fed a 30% BRK diet and exposed to stress. Animals were given supplements for 7 days before being exposed to stress, and then were given supplements for 5 days with exposure to stress. When the stress exposure ended, the animals were observed for stress-related changes in behavior and their plasma corticosterone levels were measured. BRK supplementation was associated with a partial blockade of the effects of stress on locomotion and elevated plus-maze test results in rats and mice. It was also associated with a partial reduction in stress-induced behaviors such as freezing, burrowing, smelling, face-washing, and rearing. BRK supplementation did not have a significant effect on plasma corticosterone levels, which were increased in the animals exposed to stress (p<0.01). The mice in the RG group received RG in water (2 mg RG/ mL $H_2O$), and the BRK group received a 30% BRK diet (weight) for 7 days. Both groups were evaluated for signs of fatigue. BRK supplementation increased endurance, as indicated by time on the rota-rod, in cold water, and on the horizontal wire. These results suggest that BRK supplementation partially protects the animal from the effects of stress and may also contribute to resistance to fatigue on physical exertion.

• Korean Chemical Engineering Research
• /
• v.46 no.1
• /
• pp.194-199
• /
• 2008

In this study, the effective method to esterify the free fatty acids in jatropha oil was examined. Compared to other plant oils, the acid value of jatropha oil was remarkably high, 11.5 mgKOH/g. So direct transesterification by a base catalyst was not suitable for the oil. After the free fatty acids were esterified with methanol, jatropha oil was transesterified. The activities of four solid acid catalysts were tested and Amberlyst-15 showed the best activity for the esterification. After constructing the experiment matrix based on RSM and analyzing the statistical data, the optimal esterification conditions were determined to be 6.79% of methanol and 17.14% of Amberlyst-15. After the pretreatment, jatropha biodiesel was produced by the transesterification using KOH in a pressurized batch reactor. Jatropha biodiesel produced could meet the major specifications of Korean biodiesel standards; 97.35% of FAME, 8.17 h of oxidation stability, 0.125% of total glycerol and $0^{\circ}C$ of CFPP.

• Journal of National Security and Military Science
• /
• s.8
• /
• pp.239-270
• /
• 2010

This thesis is to make an appropriate national defense policy of Republic of Korea through studying the Hegemony Strategy of United States. I searched the theory of hegemony. The hegemony was differently defined by the point of time and region. The strong power nations with the hegemony have been making efforts to maintain their hegemony everytime. I have conclusion that the presence of hegemony once emerged, it brought regional stability in place whether it is coercive or beneficial. The stability and instability of international order IS not exclusively dependent on hegemony. Even if the safety of hegemony cannot guarantee absolute stability of international order, there IS on doubt that the hegemony has enormous impact on that. According to the hegemonic theory, the history of mankind equals to the history of rising and falling hegemony. The international order was changed as the hegemony changes. The United States has been making efforts to maintain her global hegemony during the post cold-war era as well. Taking all these into consideration, relevant military strategy direction able to pursue national interest is that to make up for the relative weakness in the strategic environment. South Korea have to prepare security policy response as following. First, South Korea should build the military force equipped with advanced weapons in military technology sector and solidify military diplomatic relation able to form cooperative relation in wartime. Second, South Korea should make solid Alliance of Korea and U.S. Third, develop and maintain multilateral security cooperation of East Asia. Forth, we could realize that there are means that can neutralize opponent's strong point by seeking one or two and more asymmetry in the aspect of strategy, tactics, and means through asymmetric strategy. Than the military force of South Korea should develop into a force that is able to overcome to the traditional North Korea's threat and new type of conflicts. And the force should have sufficient strength and be deployed to effectively defend the Korean Peninsula. So, we need to establish a denial and defense system against any hostile neighboring country. Therefore, ROK military forces preparing for the future should try to construct a future military power to gradually establish enough strength for self-defense to prepare for a uncertain security environment and when the Korean Peninsula is unified in a future.