• 한국어류학회지
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• 제22권4호
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• pp.217-224
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• 2010

참홍어(Raja pulchra)는 서해지역에서 산업적으로 활용도가 높고 개체군 크기의 축소가 예상되므로 인공증식 기술 개발과 보존을 위해 일련의 연구를 수행하였다. 이 연구는 연중 대형 난각의 형태로 다회 산란하는 특성과 완전한 형태로 부화하는 치어의 특징을 기록하였다. 난소 내 난은 평균 179.8 (54~247)개로 직경이 5가지 무리로 구분되어 순차적인 산란에 기여하는 특성을 보였다. 난각은 다른 홍어류의 종과 구분되는 특징적 구조를 보였으며, 하나의 난각내에 포함되는 배의 수는 2~6개 범위이었다. 아울러 난각내에서 발생하는 자어와 부출 직전에 해당하는 치어의 형태적 특징 및 변화를 분석하여 기술하였다.

• 한국수산과학회지
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• 제29권1호
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• pp.26-34
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• 1996

1992년 5월부터 1993년 8월까지 부산 수영만 인근해역에서 채집된 망상어, Ditrema temminck의 교미 및 임신과 관련된 사항을 조직학적으로 조사한 결과는 다음과 같다. 교미시기에 성숙한 수컷은 뒷지느러미 연조의 좌우 기저부에 각각 하나씩 교미기가 돌출된다. 교미에 참여한 수컷의 이차성징지수는 3.5이상으로 나타났으며, 암컷에서 성숙난은 난소강내에 정자를 보유한 개체에서만 나타났다. 교미시 정자의 난소강내 수송형태는 정포형태이며, 교미후 난소강내의 정자는 수정시까지 약 1개월 정도의 잠복기를 가진다. 수정형은 여포강내 수정형이고, 임신형은 난소강내 임신형이며, 암컷의 발생학적 과정은 수정-배란-부화-출산으로 이어진다. 출산직전 체내자어의 크기는 전장 63.0cm정도이며, 평균 체내자어수는 모체가 전장 20.0cm인 경우 18마리 였으며 모체의 크기가 증가함에 따라 증가하는 경향을 보였다.

• 한국자원식물학회지
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• 제29권3호
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• pp.339-346
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• 2016

This study was carried out to develop an effective seed propagation method for Thalictrum rochebrunianum var. grandisepalum (H. Lev.) Nakai by analyzing seed dormancy types and germination characteristics. Seeds were collected between September to October at Gangwon province, and well-selected seeds were used while being dry-stored at 4±1℃. The seed size ranged 4.52 × 1.58 ㎜ and the weight of thousand seeds were 1,603.5 ± 0.02 ㎎. The moisture content was 7.2%. Seeds were achene type, and morphology characters showed an elliptical shape and rough texture, and light brown in color. Moist-chilling treatment was conducted for dormancy breaking because the seeds had an undeveloped embryo of liner type. The embryo had developed during a moist-chilling period, constantly, and fully developed in 10 weeks. Consequently, it seemed to be non-deep complex or intermediate complex type of morphophysiological dormancy, and embryo dormancy was broken by wet-chilling for 10 weeks. After 10 weeks of wet-chilling treatment, seed germination began. Germination percentage was higher in dark condition raher than light condition and recorded the maximum at 25℃ in the dark (16.3%). A pre-soaking treatment with a combined plant growth hormones promoted germination and shortened T₅₀. Specifically, seed germination of 84.5% was achieved by pre-soaking of seeds with a combined solution of 500 ㎎/L GA₃ and 10 ㎎/L kinetin for 24 h after a wet-chilling treatment for 10 weeks. Thus the effect of plant growth hormones coupled with chilling temperature on seed breaking dormancy provide asubsequent growth of seedlings for successful plantation.

• 한국가축번식학회지
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• 제21권1호
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• pp.31-37
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• 1997

Ultrasonographic diagnosis of genital disease and early pregnancy diagnosis was performed in Korean native cattle. The size of ovarian follicle in preovulation, luteal stage and follicular cyst was 18.9, 9.2 and 27.6 mm, respectively, and the thickness of follicular wall was 2.3, 1.8 and 2.8 mm, respectively. The size of corpus luteums in formation stage, activity stage, regression stage, cystic corpora lutea and luteal cyst was 6.2, 11.3, 8.6, 26.7 and 25.9 mm, respectively. The thickness of luteal wall in cystic corpora lutea and luteal cyst was 8.4 and 4.9 mm, respectively. The size of embryo or fetus on day 25, 27, 30, 35, 40, 45 and 50 was 0.8, 0.9, 1.3, 1.5, 2.2, 2.8 and 3.8 cm, respectively. The size of amniotic vesicle on day 25, 27 and 30 was 1.2, 2.1 and 3,0 cm, respectively. The diameter of pregnant uterus on day 25 and 27 was 7.0 and 7.8 cm, respectively. It was concluded that the ultrasonographci values determined in this study can be used as references for the treatment of genital disease and early pregnancy diagnosis in Korean native cattle.

• 한국수정란이식학회지
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• 제27권2호
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• pp.81-85
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• 2012

This study investigated the effect of birth weight on the fertility of Holstein heifers. Growth parameter (body weight) was measured at birth. Calves were analyzed as three subgroups: low (L), average (A) and high (H) birth weight (BW) calves. LBW calves were born 10 kg lighter than HBW calves. Fertility data collected included age at first breeding (AFB), number of services per conception, pregnancy rate to first artificial insemination (AI), and age at first calving (AFC). Primiparous calves in HBW are smaller compared to multiparous cows (18.3% versus 48%). Although not significantly different, LBW offspring appeared to breed faster over the service period compared with the ABW offspring that bred three weeks later on the average. The mean pregnancy rate to first AI for LBW heifers was higher (60%) than ABW (48%) and HBW (45%). HBW cows required more services per conception (2.1) than the LBW (1.7) and ABW (1.9). There were significant differences (p<0.05) in age at first calving among the different calving birth weights. Smaller birth size did not have any subsequent adverse effects on fertility. HBW offspring were more likely or tend to have worse fertility parameters.

• 한국수정란이식학회지
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• 제31권2호
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• pp.137-143
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• 2016

This study was conducted to evaluate a visual surveillance system. The advancement of recording technology and network service make it easy to record and transfer the videos. Moreover, progressed recognition technology help to make a distinction each other. Cows show distinguishing behaviors during their estrus period. The mounting is one of the behaviors. The result was different depending on the breed of the cows and the size of the farm. In the case of Korean native cattle, the estrus detection rate was 71.15%, however, dairy cows, the estrus detection rate was 39.38%. At the farms having below 6 modules, the estrus detection rate was 87.41%. On the other hand, at the farms having over 6 modules, the estrus detection rate was 77.78%. With the proper progress, the visual surveillance system can be used to detect heat detection.

• 한국수정란이식학회지
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• 제17권3호
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• pp.195-201
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• 2002

본 실험은 원시난포의 체외배양 체계를 확립할 수 있는 가능성을 검토하기 위해 0, 5, 10, 15 및 20일령 마우스에서 분리한 난소를 20, 15, 10, 5 및 0일동안 organ culture 하여 난소의 성장률, 난자의 회수율과 성장률 및 난자의 핵성숙 단계를 조사하여, 비교 ·검토하였다. 그 결과를 요약하면 다음과 같다. 1. Organ culture 전과 후의 각 일령에 따른 난소의 면적 차이는 0일령 35.9%, 5일령 8.7%, 10 일령 1.2% 및 15일령 14.4%로 15일령을 제외 하고는 배양일령이 증가할수록 면적 차이는 감소하였다. 2. Organ culture 후 난자의 회수율과 난자의 직경은 배양일령이 증가할수록 증대되었다. 3. GV기 이상의 핵성숙은 organ culture 후 배양 일령이 증가할수록 진행되는 단계에 있는 것으로 나타났다.

• Current Research on Agriculture and Life Sciences
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• 제6권
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• pp.1-6
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• 1988

The experiment was conducted to study on the physiology of developing embryo and endosperm degradation during germination of Zea mays seeds treated with GA 20 and B-Nine 5000 ppm. Data obtained can be summerized as follows : 1. Swelling of seminal root increased the section of GA treatment more or less, on the other hand, the section of B-9 treatment inhibited slightly. 2. According to elapsing of seeding date, epithelial cell of Scutellum expansed in size, and the space of cell increased, that degree was enlarged as follows ; the section of GA, the section of Control, and the section of B-9. 3. According to the elapsing of seeding date, the formation of vascular organization embryo became clearer little by little, the lignification of vascular B-9 treatment section rather higher than the other section. 4. The degradation of Starch Grain is composed of near part of epithelial cell of Scutellum, the shape of degradation radiate from element of a disk shape, and the speed of degradation is the section of GA, the section of Control, the section of B-9 in turn.

• Toxicological Research
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• 제17권1호
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• pp.27-32
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• 2001

Korean ginseng products have been fumigated with ethylene oxide (EO) for sterilization and prolongation of storage periods. However, there had been controversies indicating that consumption of EO treated foods might cause harmful effects in human. In Korea, the use EO gas for food treatment was banned in 1991. Since then, irradiation technique has been developed as an alternative. This study was carried out to evaluate the safety of irradiated ginseng on embryo and fetal developmental toxicity effects in rats. Either EO gas fumigated or $\gamma$-irradiated ginseng was administered to pregnant Wistar rats by oral gavage from gestational day 7 to 17. The amount of irradiation used in this study was 5, 10 and 30 kGy, respectively. There were no treatment related changes of dams in deaths, clinical signs, food consumption and body/organ weight. No treatment related changes in implantation ratio, litter size, sex ratio and body/organ weight of fetuses were observed. Also, no F1fetuses with external, visceral, head and skeletal mal-formation were observed. The results of this study showed that $\gamma$-irradiated ginseng, up to 30 kGy, has no adverse effects on fetal development of rats.

• 한국입자에어로졸학회지
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• 제5권4호
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• pp.171-178
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• 2009

$PM_{2.5}$ is one of critical air pollutants due to its high absorbability of heavy metallic fumes, PAH and bacillary micro organisms. Such a fine particulate matter is often formed through various nucleation processes including condensation. This study attempts to find the nucleation behaviors of $PM_{2.5}$ arisen from coal power stations using a classical heterogeneous Fletcher's theory. The numerical simulation by C-language could approximate the nucleation process of $PM_{2.5}$ from water vapor, of which approach revealed the required energy for embryo formation and embryo size and nucleation rate. As a result of the calculation, it was found that wetting agents could affect the particle nucleation in vapor condensation. In particular, critical contact angle relates closely with the vapor saturation. Particle condensation could be reduced by lowering the angles. The wetting agents aid to decrease the contact angle and surface tensions, thereby may contribute to save the formation energy.