• Clinical and Experimental Reproductive Medicine
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• 제24권1호
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• pp.35-42
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• 1997

The present study was designed to define the role of prostaglandin in the development and hatching of mouse embryo. The effects of indomethacin, an inhibitor of prostaglandin synthesis, on the development and hatching of morula and blastocyst were examined. In early morula stage, embryos were degenerated significantly at 100 ${\mu}M$ and 200 ${\mu}M$ indomethacin. However, the viability of embryos was not influenced by concentration in any other embryonic stages. In all embryonic stages, the hatching was suppressed with concentration dependent manner, but expansion was not suppressed. Particularly, in 84h embryos post hCG injection, the hatching was suppressed significantly compared with post hCG 72h or 96h embryos. When embryos were treated with 100 ${\mu}M$ indomethacin for a specific time (12h) in according to the development stage, the hatching was suppressed all groups. These suppressional effect was decreased as embryonic development stage was progressed. However, the expansion was not affected in all treatment group. This study suggests that hatching-related metabolic substances are synthesized from morula stage and intraembryonic signaling mediated prostaglandin was important for development and hatching of mouse embryo.

• 기술혁신연구
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• 제4권1호
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• pp.165-183
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• 1996

In acquiring and transferring a superior knowledge assesing the intermediate result value of a competitive R&D project is very important for a firm engaging in R&D. Most existing literatures on R&D evaluation are concerned with project selection and resource allocation. In this paper the stage of an R&D project is classified into research, exploratory development, and development. And a model is suggested which evaluates the intermediate result value before completion of development stage under duopoly and oligopolistic competition. Assessed value of the intermediate result transferred to the next tier company can be used as a minimum acceptable price to the inventor when more advanced knowledge acquired through R&D is transferred to the next tier one. The model suggested is composed of structural variables including research cost, success rates, potential profits, discount rate degree of competition. By using exponential distribution for invertion process time in each stage, we derive a formula that can assess the value of the intermediate result, and we demonstrate how the model can be applied to a competitive R&D situation through an example.

• 한국발생생물학회지:발생과생식
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• 제25권4호
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• pp.269-277
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• 2021

Effects of water temperature and hormones on ovarian development of conger eel in Korea were investigated. Ovarian development was analyzed by measuring gonadosomatic index (GSI) and oocyte diameter with histological methods. At rearing water temperatures of 12℃, 14℃, and 16℃, GSI value increased from 3.66 at the start of the experiment to 7.44, 8.82, and 7.34 at the end of the experiment, respectively. At rearing water temperatures of 12℃, 14℃, and 16℃, egg diameter increased from 245.11-300.25 ㎛ at the start of the experiment to 377.62-480.27 ㎛, 396.72-498.54 ㎛, and 382.29-475.69 ㎛ at the end of the experiment, respectively. Follicular oocyte development revealed that primary yolk globule stage observed from January to March. It entered to secondary yolk globule stage in April and remained at the same stage until July. As a result of examining effects of three hormones (human chorionic gonadotropin (HCG), luteinizing hormone releasing hormone analogue (LHRHa), and salmon pituitary extraction (SPE) on ovarian development, HCG was found to be the most effective one. The progress from diapause of the secondary yolk globule stage to migratory nucleus stage of oocytes could be induced by treating fish with HCG at 1,000 IU/kg. The effect of hormone treatment on ovarian development of conger eel in Korea was the most effective at water temperature of 14℃.

• Fisheries and Aquatic Sciences
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• 제6권2호
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• pp.51-58
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• 2003

The gonadal development and the gametogenic cycle and the fine structure of ripe germ cells of the cultured Pacific oyster, Crassostrea gigas were investigated using oysters monthly collected from the southern coast of Korea from October 2000 to September 2001. Monthly changes in the condition index were similar to that of meat weight rate and the highest value was observed in between April and May, and the lowest value in August. The external colors of the testis and the ovary were milky white and yellowish, respectively. The spawning period of the Pacific oyster was continued from May to September, with a peak in July. The gametogenic cycle could be classified into five successive stages: multiplicative stage (December to March), growing stage (March and April), mature stage (April to June), spawning stage (June to August) and resting stage (August to January). Variety of egg yolk granules, lipid granules, mitochondria, and endoplasmic reticula were observed in cytoplasm of ripe oocyte. The spermatozoon consisted of the head, middle piece and tail; including cap-shaped acrosome with domed structure, elliptical shaped nucleus, four mitochondria, two centrioles and flagellum.

• 한국발생생물학회지:발생과생식
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• 제24권3호
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• pp.225-230
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• 2020

This study reports the presence of mature and bi-sexual phase gonads in red spotted grouper, Epinephelus akaara after less than a year of cultivation in a commercial indoor tank and a net cage. In December 2018, juveniles were placed in an indoor tank and cultured for five months. In June 2019, the fish were transferred to a net cage and cultured until September. The rearing temperatures ranged from 19.86℃-24.65℃ in the indoor tank and 21.86℃-27.65℃ in the net cage. During the net cage culture period, specimens were randomly selected for histological gonad examination. The highest gonadosomatic index (GSI) value was measured in July (3.38±2.53), and dramatically decreased in August (0.44±0.21) and September (0.42±0.30). In July, some mature fish showed signs of vitellogenic stage oocyte development (vitellogenic and oil droplet stage oocytes), but immature fish were in an early developmental stage containing peri-nucleolus stage (PNS) oocytes. Bi-sexual phase gonads containing spermatocytes and spermatids were observed in the lumen and several PNS oocytes. By August and September, most specimens showed early-stage ovary development. However, mature testis (in August) and bi-sexual phase gonads (in September) were also observed. These results provide evidence for early puberty and hermaphroditism in the red spotted grouper.

• Journal of Nutrition and Health
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• 제37권7호
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• pp.566-575
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• 2004

To compare the dietary intakes and body composition in the stage of puberty, this study was conducted with 360 girls aged 9 to 12 years in Seoul Korea. Girls's general information and 3-day diet records were collected, fat mass was measured by Inbody 3.0, bone mass at right calcaneus was measured by PIXI and pubertal development was self-assessed by picture of Tanner stages. The results are as follows: Girls who had breast development were 79.7% and 15.8% had pubic hair development. Mean of BMI, BMC and BMD were significantly higher at breast stage3+(19.6 kg/$m^2$, 1.62 kg, 0.47 g/$\textrm{cm}^2$) than at the breast stage2 (18.2 kg/$m^2$, 1.47 kg, 0.44 g/$\textrm{cm}^2$) or breast stage1(16.3 kg/$m^2$, 1.32 kg, 0.39 g/$\textrm{cm}^2$) (p < 0.001). Percent body fat of breast stage1, 2, and 3+ were 19.7%, 23.1%, 25.3% respectively and significantly increased during the puberty (p < 0.001). The mean of energy intake was 1629 kcal in stage1, 1664 kcal in stage2 and 1577 kcal in stage3+ showed significant difference in the breast stages (p < 0.05). Energy adjusted sodium intakes and crude fiber intakes were significantly higher in breast stage3 + than other breast stages. For zinc and iron, proportions of subjects with intake levels less than 75% of Korean RDA was over 40% and significantly higher in breast stage3+ than other stages (p < 0.05) ; for protein and vitamin E, the proportions of subjects with intake levels more than 125% RDA was significantly higher in the stage 1. The nutrient adequacy ratio (NAR) for protein and phosphorous was significantly lower in breast stage3+ than other stages. The food groups of seed and nut were 4.7 g/day, 2.3 g/day, 1.8 g/day, respectively, and was significantly higher in breast stage 1. In summary, mean of BMI, BMD, BMC and percent of body fat were increased with pubertal development, and those who had higher breast developmental stage showed a lower amount of consumption level in energy, seeds and nuts, and also showed a higher amount of consumption level in energy adjusted sodium and fiber among Korean girls.

• 한국지역지리학회지
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• 제19권3호
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• pp.551-565
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• 2013

이 연구는 오스트레일리아 NSW 주 지리 교육과정과 이에 근거하여 개발된 지리교과서에 나타난 개발교육을 분석한 것이다. 지리 교육과정 및 교과서에 나타난 개발교육의 특징을 분석한 결과는 다음과 같다. 먼저, 지리 교육과정에서 Stage 4와 Stage 5의 필수 지리는 개발교육을 구체적으로 명시화하지 않고 삶의 질의 차이와 원조 연계를 통해 개발교육에 접근하고 있는 반면, 심화 과목인 선택 지리의 경우 개발교육을 명시화하고 있다. 뿐만 아니라 Stage 6에서도 개발지리를 구체적으로 명시하여 보다 심화하여 학습하도록 하고 있다. 다음으로, 지리 교과서에서는 개발교육이 개발에 대한 학습에서 바로 시작하는 것이 아니라 일상생활에서의 삶의 질의 차이를 선행하여 학습한 후 개발 및 개발 척도를 다양한 관점에서 균형있게 이해하도록 하고, 이러한 글로벌 불평등 해소를 위해 개인 또는 조직으로서 어떻게 행동하고 실천해야 할 것인가에 대한 학습으로 계열화되어 있다. 이러한 분석 결과를 통해 얻을 수 있는 함의는 다음과 같다. 첫째, 중등학교 저학년에서는 개발을 직접적으로 다루기보다는 이와 관련한 삶의 질의 차이를 중심으로 내용을 구성하고, 중등학교 고학년에서는 개발지리에 대해 직접 학습하도록 할 필요가 있다. 둘째, 개발교육에서 등장하는 주요 개념인 개발, 개발 척도, 원조 등의 의미를 다양한 관점에서 균형 있게 다룰 필요가 있다. 셋째, 개발교육은 우리나라와 다른 국가와의 구체적인 개발 연계 사례를 통해 추상적인 상호의존성이라는 개념과 글로벌 시민성이라는 가치를 학습하고 실천할 수 있도록 할 필요가 있다. 마지막으로 글로벌 불평등을 줄이기 위한 노력을 당위적인 측면에서 기술하거나 정부 및 비정부기구 등과 같은 조직의 차원에 한정하지 않고, 개인적인 실천 사례를 통해 그들의 가치와 행위를 감정이입하도록 할 필요가 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.311-314
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• 1997

According to the development of industrial equipment such as semiconductor manufacturing machines, optical device, and precision machine tool, a high-precision translation system with wide range has been required. This paper describes a high-precision 2-axis translation system, which consists of microstage and global stage. In order to achieve the highresolution in the long range, some engineering techniques are used. Three linear guides with flexible coupling are adopted to reduce the motor vibration in the global stage. A simple elastic hinge structure activated by five PZT is applied to reduce the angular dev~atlon. As the result of combination of microstage and global stage associated with some engineering techniques, the 2-axis translation system can measure the 200 X 200 mrn range with the nanometer accuracy.

• 한국발생생물학회지:발생과생식
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• 제16권1호
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• pp.69-75
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• 2012

Hatching occurred in the time dependent manners and strictly controlled. Although, the hatching processes are under the control of muti-embryotrophic factors and the expressed G proteins of cell generate integrated activation, the knowledge which GPCRs are expressed during hatching stage embryos are very limited. In the present study, which G proteins are involved was examined during blastocyst development to the hatching stage. The early-, expanded-, and lobe-stage blastocysts were treated with various $G_{\alpha}$ activators and H series inhibitors, and examined developmental patterns. Pertusis toxin (PTX) improved the hatching rate of the early-stage blastocyst and lobe-formed embryos. Cholera toxin (CTX) suppressed the hatching of the early-stage blastocyst and expanded embryos. The effects of toxins on hatching and embryo development were changed by the H7 and H8. These results mean that PTX mediated GPCRs activation is signaling generator in the nick or pore formation in the ZP. In addition, PTX mediated GPCR activation induces the locomotion of trophectoderm for the escaping. CTX mediate GPCRs activation is the cause of suppression of hatching processes. Based on these data, it is suggested that various GPCRs are expressed in the periimplantation stage embryos and the integration of the multiple signals decoding of various signals in a spatial and temporal manner regulate the hatching process.

• 공학교육연구
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• 제17권4호
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• pp.21-24
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• 2014

The purpose of this study is to develop the engineering students leadership program and evaluate the pilot test. To this end, literature reviews covering various leadership programs were studied and a needs analysis survey was conducted. The needs analysis survey found that student subjects believe leadership to be an important quality, but that the current availability of leadership training programs is lacking. Furthermore, results of the study are as follows, with respective results listed in descending order. The majority of students selected on-line learning as their preferred training method, followed by blended learning and in-person learning. Students also indicated their preferred instructional method to be through on-line courses. Based on these results, a preliminary pilot program was experimentally launched for only 1 class's use. This process of the development for the Engineering Leadership Program consists of 4 stages. The first stage is a needs analysis survey, followed by the design of the program based on results from the needs analysis survey. Afterwards comes the development stage, followed by the implementation stage, comprised of two parts; the pilot test and the distribution. The final stage is the overall evaluation step. We are currently in the first step of the third stage (the pilot test) and only the overall evaluation stage remains. After the distribution, a follow-up study will be conducted to analyze the effectiveness of the implemented program.