• The korean journal of orthodontics
• /
• v.48 no.6
• /
• pp.384-394
• /
• 2018

Objective: This study was performed to investigate an appropriate degree of prestretch for orthodontic synthetic elastomeric chains focusing on time-dependent viscoelastic properties. Methods: Orthodontic synthetic elastomeric chains of two brands were prestretched to 50, 100, 150, and 200% of the original length in one and three cycles, and the hysteresis areas of the obtained stress-strain curves were determined. Acrylic plates were employed to maintain constant strain during the experiment. A total of 180 samples were classified into nine groups according to brand, and their stresses and permanent deformations were measured immediately after prestretch (0 hour), after 1 hour and 24 hours, and after 1, 2, 3, 4, 5, 6, 7, and 8 weeks. The relationship between stress relaxation and permanent deformation was investigated for various degrees of prestretch, and the estimated stress resulting from tooth movement was calculated. Results: The degree of prestretch and the stress relaxation ratio exhibited a strong negative correlation, whereas no correlation was found between the degree of prestretch and the average normalized permanent strain. The maximal estimated stress was observed when prestretch was performed in three cycles to 200% of the original length. Conclusions: Although prestretch benefited residual stress, it did not exhibit negative effects such as permanent deformation. The maximal estimated stress was observed at the maximal prestretch, but the difference between prestretch and control groups decreased with time. In general, higher residual stresses were observed for product B than for product A, but this difference was not clinically significant.

• Journal of Sasang Constitutional Medicine
• /
• v.12 no.2
• /
• pp.171-183
• /
• 2000

1. Back ground and purpose An experimental study has done to examine the effect of defense and cure gastric mucasal damage of Mokdan-pijihwang-tang. 2. Methods Mice had intragastric injected with MJ extract before indomethacin treatment which induces homorrhage infarct and erosion artificially. Degree of lipid peroxidation, general morphology, change of mucous cell, the distribution of PNA, ICAM and distribution of apoptotic cell were objected. (Abbreviation) MJ : Mokdanpijihwang-tang, PNA : Peanut Agglutinin, ICAM : Intercellular Adhesion Molecule 3 Results 1) The degree of lipid peroxidation in INDO-group had increased conspicuously than control group. But the degree of lipid peroxidation in MJ-group had decreased than INDO-group and these decline had probability. 2) After indomethacin treatment, hemorrhage infarct and erosion had increased in stomach body. But in MJ-group, the configuration is normal, except the group intragastric injected with MJ extract at hour 24 before indomethacin treatment. 3) Surface mucous cell and neck mucous had disappeared in INDO-group. But in MJ-group tormal distribution had shown like control group except the group intragastric injected with MJ extract at hour 24 before indomethacin treatment. 4) PNA positive reaction had not shown in INDO-group. But medium PNA positive reaction had shown In Mj-group. 5) ICAM positive reacted cell had shown in INDO-group. The decrease of ICAM positive cell were shown than INDO-group. 6) A number of apoptotic cell was distributed in hemorrhagic erosion. A few number of apoptotic cell was distributed in MJ-group except some surface mucous. 4. Conclusion These results suggest that MJ has an effect on cure of gastric mucosal damage.

• Journal of Chest Surgery
• /
• v.10 no.1
• /
• pp.124-132
• /
• 1977

A experimental study of deep hypothermia for open heart surgery in 5 dogs was reviewed. Surface hypothermia in combination with limited cardiopulmonary bypass was employed. Circulatory dynamics were well maintained following cardiac arrest during one hour at $20^{\circ}C$. Some degree of acidosis usually developed after the arrest period but was gradually corrected during. rewarming Total circulatory occlusion could be maintained for at least one hour at $20^{\circ}C$ without evidence of cerebral damage in the dogs. Potassium in the serum after deep hypothermia was moderately decreased and it was the most severe change in the electrolyte. Free hemoglobin of serum was mild increased and it was one of advantages of combined hypothermia with limited cardiopulmonary bypass.

• Journal of Bio-Environment Control
• /
• v.25 no.4
• /
• pp.308-319
• /
• 2016

In order to set the outdoor weather conditions to be applied to the design standard of the greenhouse heating and cooling system, outdoor air temperature and heating degree-hour for heating design, dry bulb temperature, wet bulb temperature and solar irradiance for cooling design were analyzed and presented. For every region in Korea, we used thirty years from 1981 to 2010 hourly weather data for analysis, which is the current standard of climatological normal provided by KMA. Since the use of standard weather data is limited, design weather conditions were obtained using the entire weather data for 30 years, and the average value of the entire data period was presented as a design standard. The design weather data with exceedance probability of 1, 2.5, and 5% were analyzed by the TAC method, and we presented the distribution map with exceedance probability of 1% for heating and 2.5% for cooling which are recommended by design standards. The changes of maximum heating load, seasonal heating load and maximum cooling load were examined by regions, exceedance probabilities, and setpoint temperatures. The proposed outdoor design conditions can be used not only directly for the greenhouse heating and cooling design, but also for the reinforcement of heating and cooling facilities and the establishment of energy saving measures. Recently, due to the climate change, sweltering heat in summer and abnormal temperature in winter are occurring frequently, so we need to analyze weather data periodically and revise the design standard at least every 10 years cycle.

• Korean Journal of Community Nutrition
• /
• v.14 no.4
• /
• pp.441-450
• /
• 2009

The prevalence of obesity in children has steadily risen during recent years in developed countries. Child obesity has become a major concern to health providers since it has grown to epidemic proportions over the past few decades. This study was conducted to investigate the biochemical status, dietary habits and life styles according to the obesity degree among obese children residing in the Gyungbuk area. The subjects were 148 elementary school students (boy 103, girl 45) and classified as mildly obese (n = 56), moderately obese (n = 61) and severely obese (n = 31) by the obesity index. The average body weight and height increased significantly according to the obesity degree (p < 0.05, p < 0.001). Serum cholesterol concentration came under the normal level in all groups. Serum AST activity increased according to the obesity degree but it was not significant. Serum ALT activity increased according to the obesity degree (p < 0.05). Dietary habit score was lower significantly according to the obesity degree (p < 0.01). Life style of the subjects was significantly different for the level of 'healthy state (p < 0.05)', 'body perception (p < 0.01)', 'watching TV and video (p < 0.05)', 'normal sleeping hour (p < 0.05)' and 'degree of stress (p < 0.05)' according to the obesity degree. A positive relationship between obesity index and blood pressure, ALT has been shown in the subjects. Obesity index and dietary habit scores were negatively associated. Therefore, these results suggest that a practical nutrition-exercise education program for the prevention of child obesity should be provided to elementary school children. (Korean J Community Nutrition 14(4) : 441${\sim}$450, 2009)

• The Korean Journal of Physiology
• /
• v.6 no.2
• /
• pp.9-17
• /
• 1972

This experiment was carried out to investigate systematically how the aerobic metabolic capacity of renal tissue reduced by the effects of a period of induced ischemia. Aerobic metabolic studies were performed on homogenates of cortex and medulla of rabbits. Ischemia was induced by occluding the renal vein or renal artery of the left kidney for an hour. The right kidney used as a paired control. Aerobic metabolism was asesssed by measuring the oxygen consumption using the Warburg's manometric apparatus. The results are summarized as follows: 1. One hour of occlusive ischemia does not increase in the kidney weight in the renal arterial occlusion but increase in the renal venous occlusion. 2. Occlusion of either the renal vein or renal artery for an hour did not reduce to any significant degree the level of endogenous substrate in cortical homogenates as measured the rates of $0_2$ consumption. 3. A significant reduction in the rate of $C_2$ consumption was noted in the medullary homogenates of renal venous occluded kidneys while renal arterial occlusion had less of an effect. 4. The capaciy of homogenates for aerobic metabolism is not reduced by acute ischemia, because of the higher rate of oxygen consumption induced by exogenous glucose in renal vein occlusion. 5. The oxygen consumption of medullary homogenate more decreased to acute ischemia than cortical homogenates. The results of this investigation suggest that one hour circulatory stasis does not reduce major potential capacity of renal cortical tissue at the subcellular level to produce energy. In contrast, the aerobic metabolism of medullary tissue is reduced by renal ischemia. Further, both cortex and medulla appear to be more sensitive to ischemia induced by renal venous occlusion than by renal arterial occlusion.

• Journal of Nutrition and Health
• /
• v.32 no.8
• /
• pp.957-966
• /
• 1999

Underreporting of dietary intake is common and might distort analysis and interpretation of dietary surveys. This study was designed to investigate the degree of underreporting and characterastics of under-reporting group in Korean college female students. Dietary survey of 1-day 24-hour recall method was conducted on 379 college students in Seoul and Chonan areas. Physical activity and life style were aquired from questionnnaires. Underreporting was defined as energy intake(EI) lower than 0.9BMR(based metabolic rate), since EI<0.98BMR is statistically judged as bias in 1-day 24 hour recall. BMR was calculated from Schofield's equation. Proportion of underreporting was 18.7% and it's not so different from one of American or European women. Intake of nutrients except vitamin A by underreporting group was lower than other groups(p<0.001). Proportions of subjects with nutrient intake level less than 75% of Korean RDA were more than 80% in protein, Ca, Fe, vitamin A, riboflavin, niacin, zinc as well as energy. Dietary quality of underreporting group was also worse than other groups. Proportion of subjects less than 3 food groups among 5 food group was higher in underreporting group. The number of foods eaten by underreporting group were also less than those of other groups. BMI and body weight were the largest in underreporting group(p<0.05) and the trial of weight reduction was shown higher trend(p<0.01). Different in PAC and other characteristics between underreporting group and other group were not significant. Not only dietary quantity but also dietary quality were worse in the underreporting group. Furthermore underreporting in college female students seemed to be affected by body weight and concern for weight reduction.

• Journal of the Korean Society of Food Culture
• /
• v.21 no.6
• /
• pp.679-684
• /
• 2006

In this experiment, I used three samples of oils. The oils that I used were hydrated soybean oil, pure soybean oil and regular soybean oil. The group of rice was fried in the each sample of oil that had not been used for a few seconds. Rice was used after frying at 230-235$^{\circ}C$ every four hours terms and total frying hours was 12 hours. The hydrated soybean oils was least affected in rancidity. The other two oils were more affected in rancidity than the hydrated soybean oil. However, the trans fatty acid in hydrated soybean oil was 36.5%. The diameter of the poped rice that was fried in pure soybean oil and regular soybean oil that had been used 12 for hours was reduced while the diameter of the popped rice fried in the hydrated soybean oil was not reduced. Also, the groups of rice fried in the pure and the regular soybean oil that had been used for 12 hours reduced the hardness in rice while the group that fried in the hydrated soybean oil at the 12th hour kept the hardness well. In sensory evaluation, rancidity order was found apparently in the pure soybean oil that had been used for 12 hour and in the regular soybean oil that have been used for eight hours and 12 hours. Only the hydrated soybean oil did not have distinctive rancidity order at all. The degree of the crispiness was reduced in the pure soybean oil and in the regular soybean oil at 12th hour frying. However, the hydrated soybean oil preserved the crispiness well until the end of 12 hours of frying. In overall preference test, the pure and regular soybean oil that had been used for 12 hour were not preferable. In conclusion, I found that the group fried in the hydrated soybean oil was better in every evaluation than the groups fried in the pure soybean oil and in regular soybean oil. The hydrated Soybean oil may be better to be used in food manufacturing if the trans fatty acid in the hydrated soybean oil can be reduced.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.41 no.1
• /
• pp.95-102
• /
• 1996

This investigation was conducted to investigate if germination rate, degree of solute leakage and water uptake rate of seeds are a meaningful information for the selection criteria among soybean genotypes and to find out their characteristics in the variable temperature and moisture conditions encounted during long-term warehouse storage. Germination rate in soybean sprouting box and petri dish differed largely among genotypes stored for twenty months but there was little difference when stored for eight months. Length of hypocotyl was shorter at twenty months of storage than at eight months. Degree of solute leakage of Paldalkong and Pulmuwon was twice higher than that of SS88038 lines at twenty months of storage. In 30 minutes after imbibition, water uptake rate in all genotypes stored for twenty months was faster than these stored for eight months, and water uptake rate in Paldalkong and Pulmuwon stored for eight months was 1.5 and 2 times faster than in SS88038 lines. In correlation coefficients, the germination ability and emergence exhibited significantly negative correlation with degree of solute leakage at twenty months of storage. Water uptake rate in soybean seeds stored for eight months had highly significant positive correlation with degree of solute leakage in 30 minutes and one hour after imbibition while for twenty months of storage, it had highly significant positive correlation with that in 30 minutes, one hour and three hours after imbibition. In eight months of storage, the number of open micropyle had positive correlation with water uptake rate at 30 minutes after imbibiton. But in seeds stored twenty months, it wasn't correlated with water uptake.

• Fisheries and Aquatic Sciences
• /
• v.5 no.1
• /
• pp.21-27
• /
• 2002

Angiotensin I converting enzyme inhibitory activities of shelled krill (Euphausia superba) hydrolysates by autolysis and by hydrolysis with commercial proteases were analyzed. Among the proteases, Alcalase was the most effective protease for the hydrolysis of krill considering the degree of hydrolysis $(87.5\%)$ and the ACE inhibitory activity $(60\%)$. Four hour hydrolysis suggested as the most suitable and economic. In order to establish the optimum hydrolysis condition of krill, degree of hydrolysis and ACE inhibitory activity as affected by Alcalase concentration and water amount added were statistically analyzed by response surface methodology (RSM). The optimum hydrolysis condition was $2.0\%$ Alcalase hydrolysis in 2 volumes (v/w) of water at $55\% for 4 hr. The hydrolysate prepared from the optimum hydrolysis condition was fractionated by molecular weight. The lower molecular weight fraction showed the higher ACE inhibitory activity. $IC_{50}$ of the fraction under 500 Da was 0.57mg protein/mL.