• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.9
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• pp.1148-1160
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• 2007

This study was performed to document the association between eating behaviors and major risk factors for cardiovascular diseases. Those who stated that they ate a daily breakfast for male and female were 88.6% and 96.0%, $1{\sim}2$ times a week were 9.1% and 2.0%, $3{\sim}4$ times a week were 2.3% and 2.0%, respectively. Those who stated that they were overeating of $0{\sim}1$ time a week for man and female were 80.7% and 89.9%, overeating of $2{\sim}3$ times a week were 19.3% and 10.1%, respectively. Those who said that they were regular of meal time for man and female were 38.6%, and 37.4%, sometimes irregular of meal time were 14.8% and 19.2%, irregular of meal time were 46.6% and 43.4%, respectively. Those who said that they were light of eating volume for man and female were 20.5% and 25.3%, moderate of eating volume were 69.3% and 61.6%, heavy of eating volume were 10.2% and 13.1%, respectively. Those who said that they were very fast of eating speed for man and female were 15.9% and 8.1%, fast of eating speed were 51.1% and 34.3%, moderate of eating speed were 4.5% and 20.2%, slow of eating speed were 17.0% and 14.1%, and very slow of eating speed were 11.4% and 23.2%, respectively. Higher frequency of breakfast a week resulted in higher serum total cholesterol and blood sugar for the daily eating group for both genders with women having high LDL-cholesterol and HDL-cholesterol. Both group had high HDL-cholesterol and low blood sugar with less number of overeating, with men having low triglyceride and LDL-cholesterol. With regular meal, both group had low triglyceride, total-cholesterol, atherogenic index, and blood sugar with women having low LDL-cholesterol. For both groups, the triglyceride, total-cholesterol, LDL-cholesterol, atherogenic index, and blood sugar had higher figures for overeating, with men having low HDL-cholesterol and women having high HDL-cholesterol. This study revealed that less number of overeating, regular mealtime, and less volume of food intake are effective in preventing and treating for the cardiovascular diseases.

• Journal of Nutrition and Health
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• v.42 no.5
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• pp.423-433
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• 2009

Folate and vitamin $B_{12}$ are essential cofactors for homocysteine (Hcy) metabolism. Homocysteinemia has been related with cardiovascular and neurodegenerative disease. We examined the effect of folate and/or vitamin $B_{12}$ deficiency on biomarkers of one carbon metabolism in blood, liver and brain, and analyzed the correlation between vitamin biomarkers in mild and moderate homocysteinemia. In this study, Sprague-Dawley male rats (5 groups, n = 10) were fed folatesufficient diet (FS), folate-deficient diet (FD) with 0 or 3 g homocystine (FSH and FDH), and folate-/vitamin $B_{12}$-deficient diet with 3 g homocystine (FDHCD) for 8 weeks. The FDH diet induced mild homocysteinemia (plasma Hcy 17.41 ${\pm}$ 1.94 nmol/mL) and the FDHCD diet induced moderate homocysteinemia (plasma Hcy 44.13 ${\pm}$ 2.65 nmol/mL), respectively. Although liver and brain folate levels were significantly lower compared with those values of rats fed FS or FSH (p < 0.001, p < 0.01 respectively), there were no significant differences in folate levels in liver and brain among the rats fed FD, FDH and FDHCD diet. However, rats fed FDHCD showed higher plasma folate levels (126.5 ${\pm}$ 9.6 nmol/L) compared with rats fed FD and FDH (21.1 ${\pm}$ 1.4 nmol/L, 22.0 ${\pm}$ 2.2 nmol/L)(p < 0.001), which is the feature of "ethyl-folate trap"by vitamin $B_{12}$ deficiency. Plasma Hcy was correlated with hepatic folate (r = -0.641, p < 0.01) but not with plasma folate or brain folate in this experimental condition. However, as we eliminated FDHCD group during correlation test, plasma Hcy was correlated with plasma folate (r = -0.581, p < 0.01), hepatic folate (r = -0.684, p < 0.01) and brain folate (r = -0.321, p < 0.05). Hepatic S-adenosylmethionine (SAM) level was lower in rats fed FD, FDH and FDHCD than in rats fed FS and FSH (p < 0.001, p < 0.001 respectively) and hepatic S-adenosylhomocysteine (SAH) level was significantly higher in those groups. The SAH level in brain was also significantly increased in rats fed FDHCD (p < 0.05). However, brain SAM level was not affected by folate and/or vitamin $B_{12}$ deficiency. This result suggests that dietary folate- and vitamin B12-deficiency may inhibit methylation in brain by increasing SAH rather than decreasing SAM level, which may be closely associated with impaired cognitive function in nutritional homocysteinemia.

• Journal of the Korean Home Economics Association
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• v.19 no.3
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• pp.83-101
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• 1981

Under the full consideration of the growing need and importance of population education in the field of home economics in Korea, the study was carried out to verify and assess the following facts on the current issues of population education of home economists who are presently engaging in teaching professions as the teachers of middle and high school and professors of college and universities by setting its primary objectives of the study as followings; 1) to assess the degree of general knowledge and attitudes of home economists toward population education in the field of home economics, 2) to verify the problems encountered in implementing population education by home economists in its field, 3) to find an existing status of previous trainings received and other activities of population education of home economists aimed at utilizing these findings as a part of reference materials when the population education is conducted in the field of home economics. In order to attain these objectives described above, the questionnaire was carefully designed to house a total of 40 questions with good combination of multiple-choice and the simple answer questions. The mail questionnaire survey was conducted by establishing teachers of home economics at middle/high schools and college/universities as Senior Home Economists(SHE) who are from public, private liberal arts and vocational schools. The rate of response observed during the survey was 45.6 percent and the findings of the survey research are as follows: 1) Examining the status of the respondents by residence and religion, it was found that 45 percent of middle & high school teachers ar.d 59. 1 percent of college professors are residing in Seoul city area and that the largest percent of them are christian in their religion. Analyzing respondents by their ages, 56 percent of middle/high school teachers are in their 30s, 45 percent of college professors are in their 40s, and 37 percent of college teachers are in their 30s. In addition, 13 percent of the total respondents are found to be unmarried. The study also revealed that 71 percent of the college professors finished Master Degree course and 82 percent of middle/high school teachers are graduated from college level lasting 4 years. Looking over the status cf major fields of respondents, 68.4 percent of middle/high school teachers are specialized in home economic education and the college professors, on the other hand, show relatively even prortion by specializing in the order of food & nutrition science, clothes & textile science and home managerial science. As far as the length of teaching experience is concerned, a relatively longer period of teaching experience is observed in the college professors in comparison with that of middle/high school teachers. In other words, 33.3 percent of middle/high school teachers are experienced in teaching from 6 to 10 years on average while 43.9 percent of college professors show more than 16 years of experience. 2) Examining the status of existing number of children cf the respondents, one boy and one daughter pattern is predominant, showing 28.5 percent in middle/high school teachers and 21.1 percent in college professors. As for the desired number of children of unmarried respondents, it is observed that 43.8 percent of middle/high school teachers desire to have one boy and one girl, and 31.3 percent of college professors want to have one child regardless of the sex. By assessing the degree of awareness of the population education through their students, it is observed that 53 percent of middle/high school teachers and 50 percent of college professors are aware of population education in some extent and that a majority of respondents took the positive attitudes toward an inclusion of family planning components into the formal school education. Another noteworthy to observe is that a total of 84.8 percent out of middle/high school teachers pointed that the population education currently conducted at schools as a part of home economics are less sufficient than it should be. 3) Analyzing the tendency as to whether the respondents were experienced in receiving population education during the time when they were students, 75 percent of college professors and 59 percent of middle/high school teachers responded negative answers in the survey. In the mean time, a total of 50 percent of the respondents replied that they began to acknowledge the importance of population education mainly through the participation of some sort of population-education orientend seminars, experienced by 40 percent of college professors and 80 percent of middle/high school teachers. 4) What it calls attention in this study was to find that 96.5 percent of middle/high school teachers and 72 percent of college professors conduct population education to some extent during their lecture hours and that more than 80 percent of them are never experienced in teaching population and family planning contents in their regular classes. It is, on the other hand, found that no more than once was the response of those who believe themselves that they are experienced in teaching these relevant components to their students. Analyzing the contents of the subjects being taught in the class, a large percent of them are found to be consisted of population and family planning contents. According to this study, the current population education through the formal school is quite inactive. Analyzing the facts, 44.9 percent of the college professors responded that the population and family planning components are quite apart from their specialization which eventually generates lack of interest in the field. 5) It is also noticed through the study that the degree of frequency of commenting on population and family planning contents during the classes was depending significantly on their specializations which means that the degree of frequency varies from a major to another. Those who majored in home managerial science was the first one, as compared to others who majored in different specializations. Glancing over the status of correlations between ages of the respondents and numbers of seminar paticipation, it is quite clear that the aged group participated more than the younger group did, and that the most highest number of participations made by college professors were those who are in 50s. In addition, it is also found that those who are aged 20s and 60s of the respondents were the group who comments least on the contents of population and family planning at their classes. The suggestions and recommendation made through this survey research are as follows. 1) No one denies that the rapid increase of population, as compared to the limited size of land and resources, will certainly affect adversly to an enhancement of individual life quality which will, eventually, bring forth the poverty of the nation. This is the reasson why we are insisting that the world population be controlled up to an optimum level with a matter of global concerns. It is our understading that the primary aim for reducing number of population is believed to be attained only by conducting the systematic and comprehensive population education through the formal schools. Therefore, the role of home economists in the field of population/family planning education is considered very importment due to the fact that an ultimate goal of population education is placed in elevating the quality of family life by having optimum number of children through family planning program. 2) It is quite clear that home economists as teachers of formal school in all level are invited to pay their attention on redefining the ultimate goal of education and that of population education. We also understant that the primary objective of population education is to change the norm and value of the clients by replenishing the students with pertinent knowledge and attitudes on population and its related problems through a sort of education in order to attain the ultimate goal for enhancing the quality of life. There is no exception in the theory of home economics. An altimate goal of home economics is to elevate the general quality of life through an establishment of value existed in daily life. Considering the relations between population education and home economics, it is quite indespensable to bandle population components as an integral part in the field of home economics. We believe, therefore, that the senior home economists positive participation in the effort population control is more needed than it has been. 3) It is also strongly urged that population education should be a part of instructor training course for home economics. In other words, the teacher of home economics should be well aware of population and its problems by teaching interrelationship between population education and home economics, needs, contents and methods of population education during the instructor training courese for home economics. In addition, the senior home economists should be encouraged through positive participation on the short term training by types of domestic and international seminar, workshop, etc. 4) We certainly believe that the population education can not sustain itself without any backing-up of information and findings' of various and comprehensive researches of natural and social sciences. Accordingly, every senior home economist is invited to exert their maximum effort to conduct systematic study with an aim to utilize these findings and information at best in population education in the field of home economics. Therefore, we consider that the development of training material is imminent in order to provide effective and efficient population education through the for training of home economies. It should be noted that these training materials must be carefully designed, tailored and developed to meet the different classes of trainees under the considerations as to whether it is easily adaptable and infusable into the curricula of every field of home economics, and it is acceptable in the degree of difficulty and quality in its contents. 5) It is true that there are many domestic and international research rapers, reports and findings in the field of population education and family planning. However, there is a tendency that the most of research papers are heavily relying on the authors intension and preferences in its expression and publication. Under these circumstances, it is urged that the home economists should aware of the growing need of the technical training in order to keep these available information and research findings reprocessed and redesigned to insure the practical application into the population education in the field of home economics in Korea.

• Journal of dental hygiene science
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• v.8 no.3
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• pp.123-129
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• 2008

The purpose of this study was to investigate the actual conditions of the subjective oral malodor perception of the survey subjects. Through the subjective questionnaire method over about 3 months from June to August in 2007, the data was collected targeting 275 adults. Statistical methods used were Chi-square test, Fisher's exact test and One-way ANOVA. And, the following results were obtained. 1. When having seen the ratio of those who were conscious of oral malodor, the adults, who responded with saying of feeling oral malodor at present and at ordinary times, accounted for 68.4% and 79.3%, respectively. And, the adults, who responded with saying of not feeling, were indicated to be 31.6%(at present) and 20.7%(at ordinary times), respectively. 2. Almost 83.5% of total people answered that they had most severe oral malodor at the time of awakening and 51.9% of subjects answered tongue contributed to the their oral malodor. 3. About the type of oral malodor, although 37.2% of the group thought the type of oral malodor was a food smell and fetid smell was second general burning smell occurred the time of hunger(22.5%). 4. In the answers of hoping for treatment of oral malodor, 66.9% of the people showed positive response to dental treatment for controlling their oral malodor. Especially 7.3% of subjects showed very big desire for treatment. 5. In the level of oral malodor that is felt now according to the time of a meal, the case of within 1 hour after having a meal was responded to be not felt the oral malodor with 44.7%. And, there was response with saying of not feeling oral malodor in 37.6% as for 1-2 hours, 16.3% as for 2-3 hours, 14.8% as for 3-4 hours, and 23.7% as for more than 4 hours. Thus, the level of oral malodor according to the time of a meal showed the statistically significant difference(p<0.01). Through the results of this study, it could be known about whether or not being conscious of oral malodor in general people, the main cause and region for oral malodor, the importance and practicing method of tongue brush through literature. Accordingly, there is necessity of further researching and comparing whether or not being conscious of oral malodor by diversely surveying relevancy with factors of causing oral malodor based on the objective oral malodor measurement value. The future diverse researches are thought to be necessarily performed in order to prevent or reduce oral malodor.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.1
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• pp.134-145
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• 2011

The purpose of this study was to examine the work values of undergraduate-level foodservice major students. In order to assess work values of the participating students, this study adopted 'Maryland Work Values Inventory'. Data from a total of 290 surveys were collected. The participants consisted of 146 commercial foodservice major students and 144 institutional foodservice major students. Among the seven work values, both groups ranked 'job advancement' as the most important work value. Commercial foodservice major students rated 'altruism' as the least important work value, whereas it was 'stimulation' for institutional foodservice major students. 'Need for work' was evaluated statistically higher by junior and senior students compared to sophomore students of commercial foodservice major (p<0.05). In both foodservice majors, a positive relationship was found between work value scores and grade levels. All work value scores tended to be higher for students in higher grades. This tendency was especially statistically clear for the value 'need for work' for commercial foodservice major students and 'money and prestige' for institutional foodservice major students (p<0.05). There were some gaps in the work values between students with different career field choices. For the commercial foodservice majors, those interested in fine dining perceived 'satisfaction and accomplishment' and 'altruism' as more important [4.33 (p<0.05) and 4.05 (p<0.01), respectively] compared to students who had interests in fast food restaurants (4.06 and 3.67 respectively). Scores for 'satisfaction & accomplishment' (p<0.05), 'money & prestige' (p<0.001), and 'stimulation' (p<0.001) were significantly different among institutional foodservice major students. In addition, students more interested in industrial foodservice field regarded 'money & prestige' and 'stimulation' as less important as indicated by noticeably lower scores (3.74, 3.55 respectively) in comparison to the other group (p<0.001). The results of this study, which explored foodservice major students' work values, suggest that there is an increased need for the students to build up their work values as well as for the foodservice industry to offer appropriate work values to future foodservice employees.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.550-558
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• 2014

This study was conducted to investigate the distribution and the population dynamics of Hipparchia autonoe by using a line transect and Mark-Release-Recapture (MRR) at the Mt. Halla in Jeju Island. The results showed that H. autonoe was found from 1,500 m above the sea level. Total 1,493 H. autonoe with 978 males and 515 females were captured and released in the MRR study site. Among them, 518 individuals including 284 males and 234 females were recaptured. The average survival time was 2.31 days with 2.14 days for males and 3.47 days for females, indicating longer survival time in case of females than males. The daily population size of males estimated in the MRR study site was maintained about 1,000 individuals in July and gradually decreased less than 200 in August. The number of females showed peak at 335 individuals on July 24, and gradually decreased less than 120 in August. Thus, female population was 1/3 of males. The average travel distance of male and female H. autonoe were $116.8{\pm}191.9m$ and $118.4{\pm}161.5m$, respectively, indicating almost same between sexes. H. autonoe in the Mt. Halla formed single population group in the wide meadow around the Baekrokdam Lake. The highest population density of H. autonoe was occurred in the restored area from damages, where host plants such as the sheep's fescue or the food plant are abundant by artificial restoration efforts.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.4
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• pp.359-366
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• 2016

Exosome, a small vesicle secreted from cells, has diverse functions depending on cell origins and tissue types and plays a important role in cell viability and intercellular communication. Recently, many researchers have demonstrated the use of exosomes for the treatment of cancers and immune diseases, and the development of diagnostic biomarker. However, the secretion mechanism of exosome from skin cell and its physiological functions in skin remain unclear. Thus, this study aimed to explore whether keratinocyte-derived exosome affects proliferation and migration in HaCaTs. Exosomes were isolated from HaCaTs by ExoQuick-TC and then boiled or unbolied. Boiled and unboiled exosome induced proliferation in HaCaTs in a dose-dependant manner ($0.1{\sim}20{\mu}g/mL$), respectively. Boiled and unboiled exosome at concentration of $20{\mu}g/mL$ increased proliferation level in HaCaTs by $186.96{\pm}3.87%$ and $193.48{\pm}10.48%$ compared with control group. Unboiled exosome stimulated migration in HaCaTs in a dose-dependent manner ($0.1{\sim}20{\mu}g/mL$), which reached a maxium at concentration of $20{\mu}g/mL$ ($179.39{\pm}4.89%$ of control), but boiled exosome did not affect HaCaT migration. In addition, unboiled exosome ($0.1{\sim}20{\mu}g/mL$) dose-dependently stimulated sprout outgrowth in HaCats. These results demonstrate that in exosome from HaCaTs, heat-stable components such as lipid may induce HaCaT proliferation and heat-unstable components such as protein may stimulate migration and sprout outgrowth in HaCaTs, thereby leading to reepithelialization and skin-wound healing activities. It is concluded that exosomes from HaCaTs may be used as cosmetic materials.

• Journal of Korean Academy of Nursing
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• v.3 no.3
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• pp.36-49
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• 1973

This study was carried out for the objectives to collect the basic informations on the health behaviors of the elementary school children in an urban area in Korea. Seven hundred students were drawn to fill in the designed questionnaire which carries variety of Questions on health re-lated behaviors in general, eating habits, disease history, mental health, and sex education. Questionnaire were filled in by their parents. Major findings are as follows: ① 55.7% had habits of washing the hands before eating whereas 59.8% trashing their hands after toilet. The others had no idea of washing hands before eating and after toilet. ② 26,5% had habits of brushing the teeth twice a day 54.7% only once in the morning, and 2.6% once only in the evening. Thus, the idea of prevention from decayed teeth seems to be lacking among the school children. ③ Bathing habits were also inquired to get 40.3% of bathing more than once a week, 43.1% once every two weeks, and the rest of 16.6% once every one to three months. ④ 41.7% keep the regular bedding time whereas 58.3% irregular. Physical exercises were con-ducted by 76.6% on the ground while 23.5% did not practice any physical exercises at all. Of those physical exercises, rope skipping occupied 37.5%, and the other 66.9% consisted of 14 different kinds of individual type physical exercises such as gymnastic exercise. The main reasons for not enjoying exercises were different by sex; boys largely complained the inadequacy and lack of gymnastic facilities and girls felt in short of friends who could join the exercises. ⑤ 31.9% of the school children had been taking not much of food while 28.3% had unbalanced diets. Of these unbalanced diets, meat occupied 33.2% to be the priority to have an order of the following items such as vegetables, bread or noodle, and fishes as next to each. For eating habits, 88.5% take simple snack such as bread (38.4%, cookies, fruits, and candies in order. 25.8% of the children were provided such snacks or their parents regularly. Breakfast was sufficiently taken by 45.0% whereas 8.4% had never sufficiently. As to the lunch, 63.6% had sufficiently while 16.8% insufficiently. 70.6% take breakfast with all family members together and 30.4% separately. Correlation of sufficient taking of breakfast and eating together of tile family member's seems to be significant when we compare 72.5% of sufficient takers who enjoy breakfast together with the family members with 55.6% of insufficient takers who enjoy it with the family. This finding allows the investigator to point out the importance of table circumstances for children's eating. ⑥ The most common disease was catching a cold (38.8%), and the second was stomach trouble to be followed by the frequency of car sickness, headache, and skin infection. Doctors are consulted only by 23.9% when they are sick whereas 59.7% resorted to the drug stores. The lower the educational attainment of the parents, the lower the rate of visiting clinics. ⑦ 36.7% of their parents pointed out the problems of personality guidance as the most difficult thing at home 71.3% of their parents worried about and unsatisfied with their children's personality traits. Of these complains of the parents, impatience stood at the top to be tabulated at 24.1%, and 21.1% indicated narrow-mindedness. In line with this primary socialization at home, the most crucial problem seems to be related with the lack or recognition of the parents'own role when we find only 43.1% of the parents understood the importance of their own role for the home education of children; the latter group attributed tile responsibility of personality formation to the children themselves. ⑧ As to the sex educational aspects, 30.9% of children have ever asked about the physiology of reproduction or sexual matters to their parents, of those parents only 17.0% could give the constructive responses to the inquiries of the children. In companies on with these data, 25.6% recognized their own role in sex education for their own children while the large segments of the parents (51.1%) attributed the responsibility of sex education to tile low level of 38.3% who recognized the importance of sex education in the school curriculum and 25.1% of the parents insisted to wait until they get to know naturally about sex. 38.1% of the parents said they had some knowledge on sex from books while 16.9% through mass media. The next groups had common senses of sex from their own parents, school friends and other sources.

• Journal of Aquaculture
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• v.1 no.1
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• pp.67-73
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• 1988

A growth experiment of tilapia (offsprings of the hybrid between Oreochromis niloticus and O. mossambicus) under different dissolved oxygen levels in the recirculating water system was conducted at the Fish Culture Experiment Station of the National Fisheries University of Pusan from February 4 to March 5, 1986. Six tanks with a capacity of $1.8m^3$ of water each were used under the same condition of water parameters except for dissolved oxygen levels which were designated to maintain at 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 mg/$\iota$. Each tank was stocked with 90 kg of fish each averaging 64 to 69 grams. The average water temperature during the course of the experiment was $22.5^{\circ}C$. The results obtained are summarized as follows: The food conversion efficiencies were very good, being 1.05-1.11 at 3.5, 3.0, 2.5 and 2.0 mg/$\iota$ DO levels without any significant differences among them, but at 4.0 mg/$\iota$ the F. C. was 1.39 and at 1.5 mg/$\iota$ it was 1.61 being very poor compared with the others. The daily growth rate performance was best at 3.5 mg/$\iota$ dissolved oxygen level followed by 3.0 and 2.5 mg/$\iota$ with slight differences while at 4.0 and 2.0 mg/$\iota$ DO levels the growths were significantly poor, and at 1.5 mg/$\iota$ DO level it was extremely poor. In 1.5 mg/$\iota$ group, the fish did not accept feed vigorously and after feeding the fish usually concentrated around the inflow point showing oxygen deficiency response. While at 4.0 mg/$\iota$ high feeding rates tended to waste significant amounts of feed while eating and led to water deterioration, and above these levels the results is considered to lead to a waste of energy with uneconomical performance. On the other hand, at and below 2.0 mg/$\iota$ DO level the tilapia certainly showed a poor growth performance. The experiment indicates that the DO range of 2.5$\~$3.5 mg/$\iota$ is the optimum level for the good growth performance.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.251-257
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• 2011

Cobalt is a naturally occurring element found in rocks, soil, water and/or is among the harmful pollutants as generated by industrialized. In the environment, cobalt has two oxidation states, cobalt (II) (Co (II)) and cobalt (III) (Co (III)). If coastal water is contaminated by cobalt, it through the food chain can have an impact on marine ecosystems. Therefore, we examined the gametotoxic and embryotoxic effects of Co (II) at various concentrations (10, 100, 500, 1000, 2500 ppb) in the sea urchin $Hemicentrotus$ $pulcherrimus$. Spawning was induced by injecting 1 mL of 0.5 M KCl into coelomic cavity. Males released white or cream-colored sperms and females released yellow or orange-colored eggs. Experiment was begun within 30 min the collection of both gametes. The fertilization and embryo development rates test were performed for 10 min and 64 h after fertilization, respectively. The fertilization rates in the control condition (not including Co (II)) and experimental group were not significantly changed. The embryo development rates in the control condition were greater than 90% and were significantly decreased with concentration dependent manner. The normal embryogenesis rate was significantly inhibited in exposed to cobalt (II) ($EC_{50}$=71.84 ppb, 95% Cl=16.71-203.36 ppb). The NOEC and LOEC of normal embryogenesis rate were <10 ppb and 10 ppb, respectively. These results suggest that the early embryo stages of $H.$ $pulcherrimus$ have toxic effect at greater than 10 ppb of Co (II) concentration.