• 원예과학기술지
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• 제32권3호
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• pp.382-389
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• 2014

Raphanus sativus L. cv. Taebaek, a efficiently microspore-derived embryo (MDE)-forming cultivar, and 'Chungwoon', a non-MDE-forming cultivar were selected as donor plants for isolated microspore culture. Radish flower bud of 2.0 (small, S), 4.0 (medium, M), and 6.0 (large, L) ${\pm}$ 0.5 mm in length were isolated to determine the temporal relationship between flower bud size and MED yield. Anatomical observations revealed no difference in the structure of the flower buds between the two cultivars. In both cultivars, the stigmas were much longer than the floral leaf in M-sized flower buds. The MDE yields for 'Taebaek' per petri dish were 6.6 and 1.3 for M- and L-sized of flower buds, respectively, but MDE formation was not induced in the S flower buds. On the other hand, 'Chungwoon' failed to form MDEs in all flower buds. The microspore density of 'Taebaek' was 1.3 times more than that of 'Chungwoon' for M sized flower buds. Of the M-sized buds from 'Taebaek' and 'Chungwoon', 92.1 and 81.6%, respectively, were in the late uninucleate microspore stage, which is characterized by the highest frequency of MDE formation. Anatomical observations of MDE formation revealed that the microspores were able to divide to form a primordium from which cell division took place continuously in the 'Teabeak' cultivar. However, the microspores of 'Chungwoon' failed to progress beyond the primodium stage, resulting in lack of MDE formation. By contrast, after the formation of the primordium, various developmental stages of embyos from microspore were observed in the 'Taebaek' cultivar. These results can be used to determine MDE forming potentials of radish cultivars.

• Reproductive and Developmental Biology
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• 제30권1호
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• pp.27-34
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• 2006

This study was conducted to compare the reproduction ability of the wild type boar and recombinant human erythropoietin (hEPO) transgenic boar semen. Ejaculated boar semen was analyzed by flow cytometry, Elisa and IVF methods. In experiment 1, flow cytometric analysis showed that the live sperm ratio of transgenic boar sperm significantly lower (P<0.05) than that of wild type boar after incubation at 20, 22, 24 and 26 hr. In experiment 2, the presence and levels of various cytokines (IL-6, IL-10 and $TNF-{\alpha}$) to related animal reproduction in the seminal and blood plasma were examined using specific enzyme immunoassay. There was no significant difference between both groups. In experiment 3, the fertilizing capacity and developmental ability of both boar sperm were compared. The transgenic boar sperm had a significantly low capacity of penetration, sperm-zona binding, embryo development, and blastocyst formation compared to wild type sperm (P<0.05). These results suggest that transgenic boar sperm harboring hEPO gene has low sperm viability than wild type boar, and it is a reason to decrease of fertility and litter size.

• 한국수정란이식학회지
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• 제27권1호
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• pp.37-43
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• 2012

This study evaluated a method of sorting X and Y chromosomes based on size using the forward angle light scatter related refractive index (FSC) of a flow cytometer. Hanwoo bulls sperm were separated to X and Y chromosomes by the parameters of FSC or Hoechst 33342 intensity. As a result, using monitor program linked flow cytometry during sorting processing, the purities were $97{\pm}0.57$ or $96{\pm}0.67%$ for the X-fraction and $96{\pm}0.33$ or $97{\pm}1.33%$ for the Y-fraction in the two sperm sorting methods. There were no differences in the X and Y ratios (X and Y %) between the sperm sorting methods based on FSC or DNA content. The proportions of female and male embryos used for in vitro fertilization and development were $66.03{\pm}3.31$ or $69.37{\pm}1.41%$, and $70.56{\pm}2.42$ or $56.11{\pm}3.09%$ when sperm were processed using the sex sorting method by FSC or Hoechst 33342. In conclusion, further study is needed to determine the optimum procedure and improve the nozzle to enhancing sorting accuracy or efficiency. Also, the findings of this study do not negate the possibility that the difference method of sperm sorting cannot use a UV laser beam.

• 약학회지
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• 제45권2호
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• pp.190-204
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• 2001

This study was conducted to investigate for its effects on reproductive and developmental toxicity of recombinant human epidermal growth factor (rhEGF) in Sprague-Dawley rats. Male rats were administered rhEGF at doses of 1, 10, 100, and 1000$\mu$g/kg/day, respective1y, by subcutaneous injection from 63 days before and throughout to mating period until the day before sacrifice. Female rats were administered rhEGF at the same doses from 14 days before mating to day 20 of gestation or to day 21 of lactation. We examined the male and female fertility indices and maternal toxicity of F0 parental animals. Also, we examined the external, visceral, or skeletal malformation of fetuses, growth and development, behavior, and/or reproductive performance of F1 animals. At the highest dose (1,000 $\mu$g/kg), the mean body weights of F0 animals were significantly increased in males and females at 3 or 2 weeks after treatment, respective1y. No clinical signs and food intakes were observed at any time during the experimental period by rhEGF treatment. In autopsy examination, the relative and absolute liver weights significantly increased in both sexes of 1,000 $\mu$g/kg. At the highest dose (1,000 $\mu$g/kg), there was a statistically significant increase of pregnancy period and the number of dead fetuses. Moreover, significant increase of mean fetal body weight and decrease of number of live fetuses, which related to the difficult dilivery were observed in highest dose group. In Fl examination, no adverse effects on external, visceral, and skeletal malformation, physical and functional development, behavior or reproductive ability of Fl animals were observed in any group. Also, there was no significant difference between control and treated groups in copulation or fertility indices of Fl animals. These results indicate that rhEGF had no adverse effect on fertility and reproductive ability of Sprague-Dawley rats.

• 한국응용곤충학회지
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• 제25권1호
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• pp.11-16
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• 1986

이화명충(二化螟蟲) 발육(發育)의 지역적(地域的)인 차이(差異)를 조사(調査)하기 위해 전국(全國) 8 개(個) 지역(地域)에서 1984년(年) 11월(月) 하순(下旬)부터 12월(月) 하순(下旬)까지 월동중(越冬中)인 이화명충(二化螟蟲) 유충(幼蟲)을 채집(採集) 하여 1985년(年) 1월(月) 15일(日), 2월(月) 15일(日) 2차(次)에 걸쳐 가온사육(加溫飼育)하였다. 1. 용화전기간은 2차(次) 가온사육(加溫館育)에서 춘성산(春城産)이 17.9일(日)로 가장 빠르고 광산산(光山産)이 27.7일(日)로 늦었으며 1, 2차(次) 모두 위도(緯度)가 높은 지역(地域)에서 발육기간(發育期間)이 빠르고 위도(緯度)와 평균(平均) 용화전기간 사이에는 부(負)의 상관관계(相關關係)가 있었다. 2. 평균(平均) 용기간은 지역간(地域間) 큰 차(差)는 없었으며 우화(羽化)까지의 기간(期間)은 용화전기간과 같은 경향(傾向)이었다. 우화(羽化)는 위도(緯度)가 높은 지역(地域)에서 빨리, 낮은 지역(地域) 에서 늦게 되었다. 3. 우화양상(羽化樣相)은 춘성(春城), 평택산(平澤産)은 뚜렷한 peak 가 있었으나 논산(論山), 이리(裡里), 광산산(光山産)은 뚜렷한 peak가 었이 불규칙(不規則)하게 우화(羽化)하였다.

• 치과방사선
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• 제25권2호
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• pp.409-422
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• 1995

The purpose of this study was to investigate the effects of radiation on the formation of rat molar enamel at the developmental stage. The experimental animals were divided into five groups and were irradiated single dose of 396cGy ; 1 st group on 14th day of gestation, 2nd group on 19th day of gestation, 3rd group on 3 days after birth, 4th group on 8 days after birth, 5th group on 28 days after birth. The control and 1, 2, 3, and 4th experimental groups were sacrificed on 2, 4, and 6 weeks and the 5th groups were sacrificed on 1 day and 2 weeks after irradiation. Distal 1/2 and occlusal 1/3 enamel surface of lingual side of lingual cusp, and fractured surface of lingual side of lingual cusp in a longitudinal direction of the mandibular first molar were examined using scanning electron microscope. The following results were obtained. 1. The roughness of enamel surface and enamel hypoplasia were increased in a sequence of 4th, 1st, 2nd, and 3rd experimental group, and the enamel cracks were increased in the 1st and 2nd experimental group. 2. The pattern of enamel hypoplasia had a network form on the 1st and 2nd experimental group, and appeared a linear shape on the 3rd experimental group, and then the crator-like enamel defects were observed in all experimental groups (especially 1st and 2nd experimental group) except 5th. 3. Dentinoenamel junction showed the clear-cut and straight appearance except 5th experimental group. 4. There was no significant difference between 5th experimental and control group.

• 한국병원경영학회지
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• 제20권1호
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• pp.1-12
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• 2015

This study aims to examine the effect of a change of leadership on internal environment and organization effectiveness and suggest measures on effective organizational management by analyzing a change of leadership before and after 2nd generation management. There was analysis of a difference of leadership type, organizational structure, organizational culture, management resources, job satisfaction, and organizational commitment between the period of the founders and the period of 2nd generation successors by collecting data from employees of 6 hospitals in Seoul. Also there was analysis of the effect of a change of leadership on internal environment and organizational effectiveness. According to the analysis, it was demonstrated that the factor affecting job satisfaction during the period of the founder was complexity of organizational structure, and there were no factors affecting organizational commitment. In contrast, during the period of the 2nd generation successors, it was revealed that transformational leadership, centralism of organizational structure, and human resources of management resources affect job satisfaction, and transformational leadership, complexity of organizational structure, hierarchical culture of organizational culture, and human resources of management resources affect organizational commitment. Further, after the succession from the founders to 2nd generation successors, as transformational leadership increased, job satisfaction rose, and as developmental culture was reinforced and human resources increased, organizational commitment was heightened. Furthermore, as transformational leadership increased and developmental culture was reinforced, organizational commitment was heightened. Namely, as transformational leadership was reinforced resulting from the succession to 2nd generation, employees' job satisfaction and organizational commitment increased, with circumstances aiming for the actual change.

• 한국과학교육학회지
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• 제16권4호
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• pp.389-400
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• 1996

The purposes of this study were to analyze chemistry problem solving processes of middle school students and to compare their problem solving behaviors in the aspects of the cognitive developmental level of student, the success in problem solving, and the context of problem. Their failures in solving problems were also analyzed in the aspects of problem solving stage and prior knowledge. Forty-two students individually solved four problems regarding density and solubility using a think-aloud method. Students' responses were analyzed after intercoder agreement for analyzing problem-solving processes had been established to be 0.94. The results were as follows: 1. Most students solved chemistry problems following the stages of understanding, planning, and solving, while few exhibited the behaviors of the reviewing stage. There was also individual difference in the number of the stages repeated and their behaviors at each stage. 2. Most students were successful in understanding problems. However, unsuccessful and/or concrete-operational students had more difficulties in understanding problems than successful and/or formal-operational students, and students tended to have more difficulties in understanding problems in everyday contexts than in scientific contexts. 3. Successful and/or formal-operational students exhibited more behaviors of the planning stage than unsuccessful and/or concrete-operational students. Students showed more behaviors of the planning stage, but failed more at this stage, in everyday contexts than in scientific contexts. 4. Most students did not review their solutions. Successful and/or formal-operational students exhibited these behaviors more than unsuccessful and/or concrete-operational students. Students tended to exhibit the behaviors more in everyday contexts than in scientific contexts. 5. Many students failed to solve problems correctly due to the lack of prior knowledge and the inability to plan appropriately.

• 한국수정란이식학회지
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• 제24권4호
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• pp.253-257
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• 2009

To enhance the embryo preservation technology and better application of embryo transfer technique to the field (dairy science or animal reproduction. etc.), we examined the viabilities of bovine embryos produced in vitro and in vivo after cryopreservation according to their developmental stage and thawing temperature. Bovine embryos from in vivo/vitro fertilization (Hanwoo) were examined at day 7, 8, and 9. Survival rates and total cell numbers of in vivo fertilized embryos were as follows: morulae 68.8% and $67\;{\pm}\;6.0$; blastocysts 80.5% and $120\;{\pm}\;10$; expanded blastocysts 77.4% and $138\;{\pm}\;9.7$, respectively. Rates of embryo development for blastocysts and expanded blastocysts after thawing were significantly higher than that of morula stage embryos (p<0.05). While survival rates of in vitro fertilized embryos according to developmental stage showed no significant difference among groups (morula 67.9%; blastocyst 74.3%; and expanded blastocyst 79.4%), total cell numbers were significantly lower than those of other groups (morula $64\;{\pm}\;5.9$; blastocyst $116\;{\pm}\;8.7$; and expanded blastocyst $135\;{\pm}\;9.1$) For the viability according to thawing temperature, survival rate was higher in $37^{\circ}C$.

• Plant Resources
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• 제2권1호
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• pp.1-9
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• 1999

The callus from the hypocotyl region of immature embryo of Citrus junos Sieb. was efficiently induced in the $\frac{1}{2}$ MS medium containing 45uM BA after 8 weeks culture. The callus was developed into the two callus type, embryogenic callus and nonembryogenic callus, which can be distinguished by visual examination depending on color and appearence. In vitro regeneration of callus established efficiently in the hormone-free MS medium from the embryogenic callus. In order to investigate the physiological changes depending on the developmental stage of embryo, the embryo was formed in the MS medium. The embryogenic and nonembryogenic callus, and the various stages of the somatic embryo were examimed the changes of esterase activity, and their isozyme patterns as well. The protein content and esterase activities was gradually increased on the developmental stages of embryo. Total protein pattern were different by the SDS-PAGE and were appeared strong band of 23 KD in the torpedo stage. The pattern of the esterase isozyme was exhibited a difference between embryogenic callus and nonembryogenic callus. It was appered pI 6.0, 8.0, 8.2 in the embryogenic callus. Also the new band of pI 4.75 was appeared in the cotyledon. These results suggest that the changes of esterase activities and isozyme patterns are importent factor in the differentiation and development of citrus.