• Development and Reproduction
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• v.27 no.4
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• pp.175-183
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• 2023

The epididymal fat is a type of gonadal adipose tissue, which is localized closely to the testis. Even though it has been suggested that the epididymal fat is necessary for maintenance of spermatogenesis in the testis, the influence of epididymal fat on expression of testicular steroidogenic enzymes has not been examined. In the present research, expressional changes of steroidogenic enzymes in the mouse testis after 2 weeks of the surgical partial lipectomy of epididymal fat at different postnatal ages were determined by real-time polymerase chain reaction analysis. The transcript levels of all molecules at 2 months of postnatal age were significantly increased by the lipectomy of epididymal fat. However, the lipectomy at 5 months of postnatal age resulted in decreases of expression levels of all molecules examined in the testis. Except a reduced transcript level of hydroxysteroid 17-beta dehydrogenase 3, there were no significant changes of expression levels of other steroidogenic enzymes by the lipectomy at 8 months of postnatal age. At 12 months of postnatal age, the lipectomy caused a significant increase of transcript level of steroidogenic acute regulatory protein and a significant decrease of transcript level of hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1, without any expressional change of cytochrome P450 side chain cleavage, hydroxysteroid 17-beta dehydrogenase 3, and hydroxysteroid 17-beta dehydrogenase 3 in the testis. These findings suggest that the substances derived from epididymal fat could differentially influence on expression of steroidogenic enzymes in the testis during postnatal period.

• Development and Reproduction
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• v.27 no.3
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• pp.101-115
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• 2023

Environmental factors impact oyster growth, condition, and gonadal development, which is linked to gamete characteristics observed through histology. The reproductive cycle of bivalves is related to energy storage and utilization. Therefore, in this study, the year-round growth change and gonadal development of oysters were observed using histological analysis, and the biochemical composition changes were confirmed. The oysters used in this study are being nurtured in Gadeok-do, and 40 oysters were randomly sampled monthly from March 2021 to February 2022. Result of histological analysis of gonads, oysters were showed early development from December to February, late development from March and April, mature and ripe from May to July, spawned from August to October, and spent from November to December. Condition index values of oysters decreased in summer and autumn and increased again when entered the spent after spawning. The protein content of oysters was high in May, the maturity period, and the lipid content decreased during the spawning period. In addition, EPA and DHA, the major fatty acids of oysters, were low during the spawning period and high during the maturation period. As a result, this study suggested a close relationship between changes in oyster growth, biochemical composition, and the reproductive cycle.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.213-221
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• 2013

The mouth rinsing solution currently on the market is used for oral hygiene and reduction of halitosis, and alkaline ionized water is used for drinking purposes. The aim of this germiculture and observation through a microscope is to investigate the effect they have on the oral bacteria, and the results are as follows. 1. The change in the number of cultivated bacteria before and after the use of gargle was most dramatic for Hexamedin. It showed the highest rate of decrease in bacteria by 71.29%, followed by Listerine with 62.25%, Caregargle with 42.26%, Garglin with 33.52%, saline solution with 21.62%, alkaline ionized water with 16.08% and distilled water with 7.67%. 2. After careful analysis of statistics, Hexamedin was found to result in a significant decrease in the number of bacteria after gargling (p<0.05). 3. From observing through an light microscope after gram staining, it was evident that both a number of cocci and a few of filamentous were present before the use of gargle, whereas mostly cocci was present after the use of gargle. 4. The difference in the pH of oral rinses and alkaline ionized water had no significant influence on the number of oral bacteria. In conclusion, Hexamedin and Listerine, with the rate of decrease of bacteria of co71.29% and 62.25% respectively, have proven to be highly effective when applied before dental treatment. Other oral rinses and alkaline ionized water are relatively less efficient in decreasing the number of oral bacteria. Also, the decrease of bacteria is more affected by the antibacterial component of oral rinses than by the change in pH.

• Reproductive and Developmental Biology
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• v.29 no.3
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• pp.169-174
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• 2005

This study was comducted to examine the effects of culture medium, and the osmolarity and osmotic change of the culture medium on in vitro maturation of porcine oocytes and developement of porcine parthenogenetic embryos. In Experiment 1, cumulus-oocyte complexes were matured in NCSU-23, mWM and mKRB, respectively, There was no difference in maturation rate($62.1\~71.3\%$) among groups. In Experiment 2, matured oocytes in each medium were activated and cultured for 6 days in the same media. Blastocyst formation rate was higher in NCSU-23($22.9\%$) than those of others($0\~0.6\%$, P<0.05). In Experiment 3, parthenogenetic embryos were cultured for 6 days in NCSU-23 with different osmolarity(300, 280 and 256 mOsmols) adjusted by NaCl. There were no differences in development rates to the blastocyst stage($11.0\~14.4\%$) among groups. In Experiment 4, activated oocytes were cultured for 2 days in NCSU-23 with 300, 280 and 256 mOsmols and then transferred to increased or decreased osmotic condition. Blastocyst formation rate was higher in a group which was transferred from the higher osmotic condition to the lowe. osmotic condition($21.0\%$) than a contrary group( $11.8\%$, (P<0.05). This result shows that the culture medium and the osmolarity of the culture medium affect the development of porcine parthenogenetic embryos, and the change of osmolarity from the higher condition to the lower condition at a certain developmental stage can enhance the development of porcine parthenogenetic embryos.

• Korean Security Journal
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• no.22
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• pp.145-168
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• 2010

Since Alarm Monitoring Service was introduced in Korea in 1981, the market has been increasing and is expected to increase continually. Some factors such as the increase of social security need and the change of safety consciousness, increase of persons who live alone could be affected positively on Alarm Monitoring Service industry. As Alarm Monitoring Service come into wide use, the understanding of electronic security service is spread and consumer's demand is difficult, so consideration about new developmental plan is need to respond to the change actively. Electronic security system is consist of various kinds of element, so every element could do their role equally. Alarm Monitoring Service should satisfy consumer's various needs because it is not necessary commodity, also electronic security device could be easily operated and it's appearance has to have a good design. To solve the false alarm problem, detection sensor's improvement should be considered preferentially and development of new type of sensor that operate dissimilarly to replace former sensor is needed. On the other hand, to settle the matter that occurred by response time, security company could explain the limit on Alarm Monitoring System to consumer honestly and ask for an understanding. If consumer could be joined into security activity by security agent's explanation, better security service would be provided with mutual confidence. To save response time the consideration on the introduction of GIS(Global Information System) is needed rather than GPS(Global Positioning System). Although training program for security agents is important, several benefits for security agents should be considered together. The development of new business model is required for preparation against market stagnation and the development of new commodity to secure consumer for housing service rather than commercial facility service. for the purpose of those, new commodity related to home-network system and video surveillance system could be considered, also new added service with network between security company and consumer for a basis is to be considered.

• Korean Journal of Cognitive Science
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• v.15 no.4
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• pp.31-47
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• 2004

This study was carried out to examine the development of physical knowledge in children. Eighty children aged 3- to 11-year-old and 16 adults were participated in this study. Participants' knowledge about failing, sliding and sinking/floating objects was investigated to understand what kind of knowledge they had, whether their knowledge was organized as theory and what was the nature of the developmental change in physical knowledge. Results showed that, for falling object task children of all age had correct knowledge about object's falling phenomena. However, there were age differences in children's understanding of the cause of object's falling. As the children's age decreased, the frequency of explanation referring to the absence of supper rather than the gravity as the cause of falling phenomena increased. For the sliding object task, children of all age could predict the motion of sliding object correctly. But only a few 9- and 11-year-old children could understand the effect of object weight and relations between gravity, frictional force and their interactions. Children under age 7 showed no evidence of possessing these knowledge. For sinking or floating object task, children of all age and even adults showed difficulties in understanding the sinking or float phenomena per se. For the cause of these phenomena although a few 9- and 11-year-old children referred to buoyancy as the cause, they had no correct knowledge about the buoyancy. This was also true for the adults. As a conclusion, the results of this study suggested that, not 3, but as young as 5-year-old children's physical knowledge exited as a form of naive theory in terms of their use as a causal devise in explaining the cause of object motion. However, even the theory of 9- and 11-year-old children was lack of the abstractness and coherence, which were also important characteristics of a theory. Finally, developmental change in physical knowledge proceeded toward more frequent and consistent use of physical knowledge as causal device and more abstract and coherently organized theory.

• Korean journal of applied entomology
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• v.62 no.3
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• pp.183-191
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• 2023

After examining the temperature change in berry sawdust during the fermentation period and the developmental characteristics of Protaetia brevitarsis larvae according to the fermentation period, it was found that the fermentation speed was faster than with oak sawdust and a fermentation period of 50-70 days was the most suitable for larval growth. During the fermentation period, the temperature change in sawdust was quickly fermented as berry sawdust passed a high temperature of more than 60℃ in the early stages of fermentation compared to fermentation speed of oak sawdust, and stabilized within 60 days. In individual breeding, the total growth period of P. brevitarsis larvae by fermentation period was the longest at 104.8 days after fermentation for 30 days, which was a significant difference. There was no difference in the growth period between 50 and 90 days of fermentation. Oak sawdust tended to be the same as berry sawdust, but the larval development period was approximately 30 days. The developmental period by larval stage differed greatly between berries and oak sawdust. The weight of larvae according to the fermentation period of sawdust was the lowest after 90 days of fermentation, with a long fermentation period for both berry and oak sawdust, and there was no difference in the 30-70 days fermentation periods. The survival rate was more than 95% in individual breeding, and there was no difference among the fermentation periods. However, in group breeding, the survival rate was lower than that of individual breeding and was lowest at 90 days of fermentation. In group breeding, the ratio of larvae weighing ≥ 2.5 g, which is the standard for shipment, was 85% after 30-70 days of fermentation of berry sawdust, but was lower at 70% after 90 days of fermentation, which was a significant difference. The survival rate with oak sawdust showed the same trend, which was approximately 10% lower than that with sawdust. In addition, the larvae from the berry sawdust weighed > 2.5 g in 40-60 days, while it took 75-105 days with oak-fermented sawdust.

• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.590-596
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• 2019

Numerous deaths and substantial property damage have occurred recently due to frequent disasters of the highest intensity according to the abnormal climate, which is caused by various problems, such as global warming, all over the world. Such large-scale disasters have become an international issue and have made people aware of the disasters so they can implement disaster-prevention measures. Extensive information on disaster prevention actively has been announced publicly to support the natural disaster reduction measures throughout the world. In Japan, diverse developmental studies on disaster prevention systems, which support hazard map development and flood control activity, have been conducted vigorously to estimate external forces according to design frequencies as well as expected maximum frequencies from a variety of areas, such as rivers, coasts, and ports based on broad disaster prevention data obtained from several huge disasters. However, the current reduction measures alone are not sufficiently effective due to the change of the paradigms of the current disasters. Therefore, in order to obtain the synergy effect of reduction measures, a study of the establishment of an integrated system is required to improve the various disaster prevention technologies and the current disaster prevention system. In order to develop a similar typhoon search system and establish a disaster prevention infrastructure, in this study, techniques will be developed that can be used to forecast typhoons before they strike by using artificial intelligence (AI) technology and offer primary disaster prevention information according to the direction of the typhoon. The main function of this model is to predict the most similar typhoon among the existing typhoons by utilizing the major typhoon information, such as course, central pressure, and speed, before the typhoon directly impacts South Korea. This model is equipped with a combination of AI and DNN forecasts of typhoons that change from moment to moment in order to efficiently forecast a current typhoon based on similar typhoons in the past. Thus, the result of a similar typhoon search showed that the quality of prediction was higher with the grid size of one degree rather than two degrees in latitude and longitude.

• Journal of Music and Human Behavior
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• v.15 no.1
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• pp.51-68
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• 2018

The purpose of this study was to examine the use of music by international college students in Korea. A questionnaire was administered to foreign college students. The questionnaire was composed of 25 items regarding use of music, the purpose of music use, and demographic information. A total of 150 questionnaires were distributed, and 81 questionnaires were returned. Incomplete questionnaires were excluded, and the remaining 69 questionnaires were analyzed. The results of this study were as follows. First, international students in Korea preferred listening to music over playing instruments or singing and mostly listened to popular music in their dormitory alone. They mostly listened to popular songs with love related themes and preferred music from their own country over Korean music. Second, in terms of the purpose behind music use, comfort was the reason reported most frequently, followed by mood change, enjoyment, sense of belonging, and sense of achievement. Third, there were no significant differences in use of music depending on individual factors (e.g., gender, length of residence in Korea, length of previous music education), but significant differences were found for using music for the purpose of mood change and sense of belonging based on respondents' length of residence in Korea. The results of this study may contribute to the development of musical programs for cultural adaptation and psycho-emotional support for international students in Korea.

• Research in Community and Public Health Nursing
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• v.10 no.1
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• pp.227-238
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• 1999

The goal of this study is to discover the effect of sex education on sex-related knowledge and attitudes of middle school girls. Non-equivalent control group pretest-posttest design was used. The number of experimental group students was 134 and the number of control group students was 134. A total of 268 second grade middle school girls were selected for a convenience sampling method. This study was carried out in a middle school located in Taegu City, Korea, from February 5 to February 18, 1998. To des cover the needs of sex education, the researcher sent a predesigned questionnaire to 1464 girls in 19 different middle schools. The sex education curriculum was designed on the basis of this survey's results. 'The Sex Education Teaching Plan' (published by the Research Institution of Korean School Health Education) and 'Sex and Happiness' (published by the Seoul City Education Ministry) were used to redesign the sex education curriculum and content. Fifty minute long sex education classes were taught to the experimental group every other day and the total number of classes was five. The contents of the teaching -learning plan for sex education were: 'The Characteristics of Adolescence', 'Pregnancy and Contraception', 'Friendship with the Opposite Sex and Prevention of Sexual Violence', 'Prevention of Venereal Disease', and 'Sex and Society'. To measure the degree of sex knowledge of the subjects, the researcher used the modified sex knowledge tools of Kim(l995) and Han(1997). The reliability values of these sex knowledge tools range from 0.71 to 0.74, using Cronbach's alpha. To measure the degree of sex attitude in the subjects, the researcher used the modified sex attitudes tools of Han(l997). The reliability values of these sex attitude tools range from 0.73 to 0.78 using Cronbach's alpha. The PC-SAS package program was used to analyse the data along with Frequency, Percentage, XLtest, t -test, and a paired t -test The results of this study were as follows; 1. The first hypothesis was accepted. The experimental group showed more change in sex - related knowledge than the control group(t =22. 76, p=0.0001). 2. The second hypothesis was accepted. The experimental group showed more change in sex-related attitudes than the control group (t=11.91, p=0.0001). In conclusion, the level of sex-related knowledge and sex-related attitudes of middle school girls who received sex education was higher than that of the girls who did not receive sex education. According to this research, planned sex education was effective in forming accurate knowlege and appropriate attitudes related to sex. Clearly, we must carry out a well-designed step by step sex education program that is well-suited to the sex education needs and the developmental level of the students.