• Title, Summary, Keyword: nuclear transfer

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Viability of Nuclear Transfer Bovine Embryos after Embryo Transfer (소 핵이식란의 이식 후 생존성에 관한 연구)

  • 정희태;임석기;박춘근;양부근;김정익
    • Korean Journal of Animal Reproduction
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    • v.22 no.2
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    • pp.153-161
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    • 1998
  • This study was conducted to examine the viability of nuclear transfer bovine embryos following embryo transfer. Donor embryos were treated with nocodazole to arrest their cell-cycle-stage at mitotic(M) phase. After releasing from nocodazole blastomeres were separated and transferred into the enucleated oocytes(BC), or cultured in medium with aphidicolin. Freshly cleaved blastomeres within 1.5h after cleavage(AC) and non-cleaved ones up to 3h after releasing from nocodazole(NC) were transferred into the enucleated oocytes. Blastocysts derived from nuclear transfer were transferred to Day 7~8 recipient cows. Some blastocysts were vitrified and thawed before embryo transfer. Developmental rates to the blastocyst stage were higher in AC(18.1%, P<0.05) than BC(8.6%) and NC(5.1%). Blastocyst development slightly enhanced with aphidicolin(1~2$\mu\textrm{g}$/ml) treatment(16.9~22.6%) compared to non treated control(11.1%). Survival rate fo vitrified nuclear transfer embryos after thawing was 75%(24/32). Twnety-three vitrified nuclear transfer embryos and 3 fresh ones were transferred to 23 recipients, 6 heads were pregnant and 1 male calf(24 kg) was born from a recipient cow recevied one vitrifiedthawed nuclear transfer embryo at 277 days after embryo transfer. This result suggests that the nuclear transfer embryos can developed to term after vitrification andembryo transfer.

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Research on heat transfer coefficient of supercritical water based on factorial and correspondence analysis

  • Xiang, Feng;Tao, Zhou;Jialei, Zhang;Boya, Zhang;Dongliang, Ma
    • Nuclear Engineering and Technology
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    • v.52 no.7
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    • pp.1409-1416
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    • 2020
  • The study of heat transfer coefficient of supercritical water plays an important role in improving the heat transfer efficiency of the reactor. Taking the supercritical natural circulation experimental bench as the research object, the effects of power, flow, pipe diameter and mainstream temperature on the heat transfer coefficient of supercritical water were studied. At the same time, the experimental data of Chen Yuzhou's supercritical water heat transfer coefficient was collected. Through the factorial design method, the influence of different factors and their interactions on the heat transfer coefficient of supercritical water is analyzed. Through the corresponding analysis method, the influencing factors of different levels of heat transfer coefficient are analyzed. It can be found: Except for the effects of flow rate, power, power-temperature and temperature, the influence of other factors on the natural circulation heat transfer coefficient of supercritical water is negligible. When the heat transfer coefficient is low, it is mainly affected by the pipe diameter. As the heat transfer coefficient is further increased, it is mainly affected by temperature and power. When the heat transfer coefficient is at a large level, the influence of the flow rate is the largest at this time.

APPLICATIONS OF ELECTROPLATING METHOD FOR HEAT TRANSFER STUDIES USING ANALOGY CONCEPT

  • Ko, Sang-Hyuk;Moon, Deok-Won;Chung, Bum-Jin
    • Nuclear Engineering and Technology
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    • v.38 no.3
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    • pp.251-258
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    • 2006
  • This study presents an idea of using analogy concept to the heat transfer studies regarding the HTGR development. Theoretical backgrounds regarding the idea were reviewed. In order to investigate the predictability of a mass transfer system for heat transfer system phenomenology, an electroplating system coupled with a limiting current technique was adopted. Test facilities for laminar forced convection and natural convections under laminar and turbulent conditions were constructed, for which heat transfer correlations are known. The test results showed a close agreement between mass transfer and heat transfer systems, which is an encouraging indication of the validity of the analogy theory and the experimental methodology adopted. This paper shows the potential of the experimental method that validates the little-understood heat transfer phenomena, even in complex geometries such as HTGR.

Systems for Production of Calves after Embryo Transfer of Nuclear Transplant Embryos (소 핵이식 수정란에 의한 산자 생산에 관한 연구)

  • 황우석
    • Journal of Embryo Transfer
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    • v.10 no.1
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    • pp.83-90
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    • 1995
  • Production of calves after transfer of nuclear transplant embryos is the latest technology to be applied in commercial livestock breeding. The objective of this study was to establish an efficient procedure to produce offsprings from nuclear transplant embryos. The fusion rates (72.7% vs. 80.8%), cleavage rates (62.5% vs. 71.4%) and rates of development in vitro (12.0% vs. 15.2%) of nuclear transplant embryos were not significantly different between 30 and 40h maturation age of cytoplast. The in vivo and in vitro-derived embryos as nuclei donor were used in this system of bovine nuclear transplantation. Fusion rates of nuclear transplant embryos were not significantly different between in vivo and in vitro-derived embryos (73.0 and 79.2%, respectively). The percentage of embryos reaching the morulae or blastocysts were 21.8% for in vivo-derived embryos and 11.9% for in vitro-derived embryos (p<0.01). Pregnancy rates after embryo transfer of nuclear transplant embryos were not significantly different between in vivo and in vitro-derived embryos (45.9 and 40.5%, respectively). However, calving rates after embryo transfer of nuclear transplant embryos were significantly higher in the in vivo-derived embryos than in vitro (p<0.01). Further research for age of cytoplast and use of in vitro-derived embryos as nuclei donor is required in this system. In conclusion, these results clearly show that the use of in vitro-derived oocytes as recipient cytoplast can improve the nuclear transplant system for genetic progress in cattle.

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Effects of the Training Transfer Management on the Workers in Nuclear Power Plants

  • Kim, Seonsu;Luo, Meiling;Lee, Yong-Hee
    • Journal of the Ergonomics Society of Korea
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    • v.33 no.1
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    • pp.49-58
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    • 2014
  • Objective: The aim of this study is to enhance the efficiency of education and training through application and management of 'Transfer of Training' in nuclear power plants. Background: Despite the sophistication and standardization of job-related skills and techniques of workers, accidents/incidents keep taking place due to human errors and unsafe actions and behaviors, which translates into the necessity to review and examine the effectiveness and influence of education and training on the workers of nuclear power plants. Method/Results: This study drew the factors of 'Transfer of Training' through a review on the preceding studies and document research. In addition, through expert examination, this study explored the expected effects and possibility of application when managing the influencing factors of 'Transfer of Training' in nuclear power plants. And lastly, management priority order for nuclear power plants was drawn through an AHP analysis. Conclusion: Among the 'Transfer of Training' factors, the training design factor was the most important. In addition, the design of the training and transfer and goal setting showed a high degree of importance among the influencing factors. Application: The management of 'Transfer of Training' in nuclear power plants enhances the capability of workers and improves the operational integrity of nuclear power plants.

Heat transfer and flow characteristics of a cooling thimble in a molten salt reactor residual heat removal system

  • Yang, Zonghao;Meng, Zhaoming;Yan, Changqi;Chen, Kailun
    • Nuclear Engineering and Technology
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    • v.49 no.8
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    • pp.1617-1628
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    • 2017
  • In the passive residual heat removal system of a molten salt reactor, one of the residual heat removal methods is to use the thimble-type heat transfer elements of the drain salt tank to remove the residual heat of fuel salts. An experimental loop is designed and built with a single heat transfer element to analyze the heat transfer and flow characteristics. In this research, the influence of the size of a three-layer thimble-type heat transfer element on the heat transfer rate is analyzed. Two methods are used to obtain the heat transfer rate, and a difference of results between methods is approximately 5%. The gas gap width between the thimble and the bayonet has a large effect on the heat transfer rate. As the gas gap width increases from 1.0 mm to 11.0 mm, the heat transfer rate decreases from 5.2 kW to 1.6 kW. In addition, a natural circulation startup process is described in this paper. Finally, flashing natural circulation instability has been observed in this thimble-type heat transfer element.

In Vitro Development of Reconstructed Bovine Embryos and Fate of Donor Mitochondria Following Nuclear Injection of Cumulus Cells

  • Do, Jeong-Tae;Lee, Bo-Yon;Kim, Seung-Bo;Lee, Hoon-Taek;Chung, Kil-Saeng
    • Proceedings of the KSAR Conference
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    • pp.11-11
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    • 2001
  • In this study, we examined the developmental potential of reconstructed bovine embryos and the fate of donor mitochondria during their preimplantation development after nuclear transfer. Isolated cumulus cells were used as donor cells in nuclear transfer. Cumulus cells labelled with MitoTracker Green FM fluorochrome were injected into enucleated bovine MII oocytes and cultured in vitro. MitoTracker labelling on donor cells did not have a detrimental effect on blastocyst formation following nuclear transfer. Cleavage rate was about 69%(56/81) and blastocyst formation rate was 6.2% (5/81) at 7 days after nuclear transfer. The labelled mitochondria dispersed to the cytoplasm and became distributed among blastomeres and could be identified up to the 8- to 15-cell stages. Small patches of mitochondria were detected in some 8- to 15-cell stage embryos (5/20). However, donor mitochondria were not detected in embryos at the 16-cell stage and subsequent developmental stages. In the control group, mitochondria could be identified in arrested 1-cell embryos up to 7 days after nuclear transfer These results suggest that donor mitochondria disappear from recipient cytoplasm before 16-cell stage following nuclear transfer in reconstructed bovine embryos.

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Factors Affecting the Development of Embryos Produced by Nuclear Transfer

  • Lee, Joon-Hee;Campbell, Keith H.S.
    • Journal of Embryo Transfer
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    • v.27 no.4
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    • pp.193-203
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    • 2012
  • The development of embryos reconstructed by nuclear transfer is dependent upon numerous factors including the type of recipient cell, method of enucleation, the type of donor cell, method of reconstruction, activation, the cell cycle stage of both the donor nucleus and the recipient cytoplasm and the method of culture of the reconstructed embryos. Many of these points which have been reviewed extensively elsewhere (Sun and Moor, 1995; Colman, 1999; Oback and Wells, 2002; Renard et al., 2002; Galli et al., 2003b), here we will concentrate on main area, the production of suitable cytoplast and nuclear donor, nuclear-cytoplasmic coordination, oocyte activation, culture of reconstructed embryos, and the effects that this may have on development.

Gamma ($\GAMMA$) Tubulin and Microtubule Assembly in Porcine Nuclear Transfered Embryos and Parthenotes

  • Hong, Jun-Soon;Park, Sang-Hyun;Shun, Cui-Xiang;Kim, Nam-Hyung
    • Proceedings of the KSAR Conference
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    • pp.51-51
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    • 2002
  • Despite of importance of integrated events of nucleus and microtubule remodeling in nuclear transferred embryos with somatic cells, little information is available on this subject. In this study we compared chromatin, r-tubulin and microtubule organization in porcine oocytes following somatic cell nuclear transfer and parthenogenetically activation in order to clarify nuclear remodeling process and to demonstrate centrosome inheritance during nuclear transfer. (omitted)

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A Study on the Correlations Development for Film Boiling Heat Transfer on Spheres

  • Jeong, Yong-Hoon;Beak, Won-Pil;Chang, Soon-Heung
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.437-442
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    • 1998
  • Film boiling is the heat transfer mechanism that can occurs when large temperature differences exist between a cold liquid and hot material. In the nuclear reactor safety analysis, film boiling has become an important issue in recent years. During severe accident, hot molten corium fall into relatively cool water, and fragment into spheres or sphere-like particles. If the steam explosion is triggered, the thermal energy of corium is converted into the mechanical energy that can threaten the integrity of reactor vessel or reactor cavity. One of the important concerns in the heat transfer analysis during pre-mixing stage is the film boiling heat transfer between the corium and water/steam two-phase flow. Until now, considerable works on film boiling heat been performed. However, there is no available correlation adequate for severe accident analysis. In this study, boiling heat transfer correlations have been developed, and their applicable ranges heat been enlarged and their prediction accuracy has been enhanced.

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