• Nuclear Engineering and Technology
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• 제32권4호
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• pp.395-409
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• 2000

Parametric studies were performed to assess the sensitivity in determining the maximum in-vessel heat removal capability from the core material relocated into the lower plenum of the reactor pressure vessel (RPV）during a core melt accident. A fraction of the sensible heat can be removed during the molten jet delivery from the core to the lower plenum, while the remaining sensible heat and the decay heat can be transported by rather complex mechanisms of the counter-current flow limitation (CCFL) and the critical heat flux (CHF）through the irregular, hemispherical gap that may be formed between the freezing oxidic debris and the overheated metallic RPV wall. It is shown that under the pressurized condition of 10MPa with the sensible heat loss being 50% for the reactors considered in this study, i.e. TMI-2, KORI-2 like, YGN-3&4 like and KNGR like reactors, the heat removal through the gap cooling mechanism was capable of ensuring the RPV integrity as much as 30% to 40% of the total core mass was relocated to the lower plenum. The sensitivity analysis indicated that the cooling rate of debris coupled with the sensible heat loss was a significant factor The newly proposed heat removal capability map (HRCM) clearly displays the critical factors in estimating the maximum heat removal from the debris in the lower plenum. This map can be used as a first-principle engineering tool to assess the RPV thermal integrity during a core melt accident. The predictive model also provided ith a reasonable explanation for the non-failure of the test vessel in the LAVA experiments performed at the Korea Atomic Energy Research Institute (KAERI), which apparently indicated a cooling effect of water ingression through the debris-to-vessel gap and the intra-debris pores and crevices.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.84-84
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• 2002

The advantages of the OPS techniques(Vajta G et al, Mol Reprod Dev 51: 53-58,1998) give 1) high survival rates of various types of eggs, 2) quick and simple process, 3) inexpensive equipment and reduced chilling injury. The efficiency of IVM/IVF technique in the porcine species is relatively lower than that obtained in other species such as ruminants. Two experiments were designed to investigate the effects of in-vitro fertilization of porcine oocytes matures using different OPS protocol for chilling and warming of vitrification. Porcine oocytes from ovaries collected at abattoir were matured for 44 hours in TCM199 Earle's salt supplemental with pyruvate, pff, L-cysteine, hormones and gentamycin. Oocytes were denuded and fertilized with frozen boar semen by common method. Porcine embryos produced routinely by in-vitro culture system of NCSU23 medium. The vitrification and the warming were conducted by OPS method with the glass micropipette instead of straw vessels and modified the protocol of G.Vajta(1999). In Exp 1, Chilling/Warming:Holding Medium(HM)+EG+DMSO/HM +sucrose Medium(SM) at 39$^{\circ}C$ warm stage. In Exp 2, : PBS+CS+EG+Ficoll+ Trehalose/PBS+Trehalose at 25$^{\circ}C$ stage. Filling, freezing, packing, thawing out and further culturing were performed to follow the basic protocol of G Vajta. During IVM-lVC and post-warming, fertilization parameter and developmental potential were compared to and statistically analysed. It was not significantly different from Exp 1 and Exp 2 but 25$^{\circ}C$ of stage was slightly higher on the morula/blastocyst forming rate and better atmosphere for worker than that at 39$^{\circ}C$ stage.

• 한국수정란이식학회지
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• 제19권3호
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• pp.301-306
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• 2004

본 연구는 개의 신선 및 동결 정소상체 정액과 정소상체 정액을 saline가 tris-buffer액으로 희석하고 원심분리에 의해 정장성분을 제거한 정액의 성상과 및 동결보존 시의 생존성 및 난포란과 정소상체 정자의 체외수정 후 체외수정율과 분할율에 대해 조사하였다. 개 정소상체 정액을 saline으로 희석한 정액을 20분간 배양했을 때 정자농도는 3.50$\pm$0.80${\times}$l0$^{6}$ cells/$m\ell$, 정자의 활력은 72.45$\pm$4.55%, 기형정자 수는 7.40$\pm$1.20%로 나타났으며, 대조군인 사출정액의 정자농도는 5.45$\pm$0.50${\times}$$10^{6}$cells/$m\ell$, 정자의 활력은 92.55$\pm$4.65%, 기형정자 수는 3.25$\pm$0.45%와 비교할 때 정자농도와 활력은 낮았으며, 기형정자 수는 많았다. 개 정소상체 정액과 tris-buffer로 희석한 정액을 20분간 배양했을 때 정자농도는 3.80$\pm$0.36${\times}$$10^{6}$ cells/$m\ell$, 정자활력은 78.45$\pm$3.50%, 기형정자 수는 5.54$\pm$0.85%였으며, 희석하지 않은 정소상체 정액의 성상에 비해 약간 높게 나타났다. Tris-buffer로 희석한 개 정소상체 정액을 동결 융해했을 때 생존율은 57.50$\pm$4.20%, 활력은 52.70$\pm$5.50%였으며, 희석하지 않은 대조군의 생존을 74.50$\pm$6.25%와 활력 78.50$\pm$5.20%에 비해 현저히 높게 나타났다. 개 난포란과 신선 몇 동결 정소상체 정자와 체외수정시켰을 때 체외수정율은 각각 63.10$\pm$6.45%, 49.50$\pm$4.28% 및 42.84$\pm$5.90%, 22.30$\pm$5.60%로서 신선 정자에 비해 동결 정소상체 정자로 수정시킨 군의 분할율이 유의하게 낮았다.

• 한국수정란이식학회지
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• 제19권3호
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• pp.307-313
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• 2004

본 연구는 고양이의 신선 및 동결 정소상체 정액과 정소상체 정액 성상과 및 동결보존시의 생존성 및 난포란과 정소상체 정자의 체외수정 후 체외수정율과 분할율에 대해 조사하였다. 고양이 정소상체 정액의 정자농도는 3.25$\pm$0.75${\times}$$10^{6}$ cells/$m\ell$, 정자의 활력은 70.85$\pm$4.20%, 기형정자 수는 8.55$\pm$1.85%로서 대조군인 사출정액의 정자농도는 5.05$\pm$0.40${\times}$$10^{6}$ cells/$m\ell$, 정자의 활력은 90.24$\pm$455%, 기형정자 수는 4.20$\pm$0.50%와 비교할 때 정자농도와 활력은 낮았으며, 기형정자 수는 많았다. 고양이 정액과 tris-buffer로 희석한 정액을 20분간 배양했을 때 정자농도는 3.50$\pm$0.40${\times}$$10^{6}$ cells/$m\ell$, 정자활력 은 75.50$\pm$2.55%, 기 형정자 수는 6.75$\pm$0.58%로서 희석하지 않은 정소상체 정액의 성상에 비해 약간 높게 나타났다. Tris-buffer로 희석한 고양이 정소상체 정액을 동결 융해했을 때 생존율은 54.50$\pm$4.45, 활력은 47.50$\pm$6.40%로서 희석하지 .않은 대조군의 생존을 74.50$\pm$6.25%와 활력 78.50$\pm$5.20%에 비해 현저히 높게 나타났다. 고양이의 난포란과 신선 및 동결 정소상체 정자를 수정시켰을 때 체외수정율과 분할율은 68.30$\pm$5.35%, 57.25$\pm$4.35% 및 48.65$\pm$4.95%, 35.65 $\pm$4.75%로서 신선 정자에 비해 동결 정소상체 정자로 수정시킨 군의 분할율이 유의하게 낮았다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권12호
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• pp.1716-1721
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• 2006

The present study was conducted to observe the effect of osmolality of glycerolated TEST-yolk glycerol extenders on post-thawing sperm kinematics of ram spermatozoa of the native Malpura breed maintained in a semi-arid tropical environment. Good quality semen obtained from adult rams was pooled, split and diluted to 1,000 million spermatozoa per ml in complete TEST-yolk-glycerol extenders of 900, 1,200, 1,500 and 1,800 mOsm/kg osmolality. Diluted semen samples were loaded in 0.25 ml straws and cooled down to $-125^{\circ}C$ freezing temperature at the rate of $-25^{\circ}C$ per minute under controlled conditions before plunging into liquid nitrogen for storage. The thawing of straws was performed at $50^{\circ}C$ in a water bath for 10 seconds and sperm kinematics of the frozen-thawed spermatozoa were assessed by a computer-assisted sperm analysis technique. Osmolality of diluent had no significant effect on post-thawing % motility, % rapid, % medium and % slow moving frozen-thawed spermatozoa but significantly (p< 0.05) affected the % linearity and % straightness. The post-thawing % motility and % rapid motile spermatozoa were highest in samples extended in diluent of 1,500 mOsm/kg osmolality and lowest in 900 mOsm/kg. The curvilinear velocity of spermatozoa was significantly (p<0.05) higher for samples extended in 1,800 mOsm/kg, compared to those in 900 and 1,200 mOsm/kg, but the effect was not significantly different to those extended in diluent of 1,500 mOsm/kg osmolality. The study indicated that ram spermatozoa could tolerate a wide osmolality range for dilution in the complete TEST-yolk-glycerol extender for their cryosurvival. The highest recovery of motile spermatozoa following thawing was achieved in samples extended in the TEST-yolk-glycerol diluent of 1,500 mOsm/kg osmolality.

• 한국가축번식학회지
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• 제25권3호
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• pp.219-225
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• 2001

토끼 배아세포(Embryonic Stem Cell)를 분리하기 위해 토끼 1-cell embryo를 채란하여 in vitro에서 blastocyst까지 배양한 후 mouse embryonic fibroblasts(MEF), rabbit embryonic fibroblasts(REF) 및 STO cell expressing Leukemia Inhibition Factor gene(SNL) feeder cell과 공배양하였다. 외관상 충실한 토끼 배아세포 8 개를 확보하였고 분리된 토끼 ES cell의 모양은 주위에 분화된 세포가 없는 전형적인 colony모양으로 성장하고 액체질소에 동결보존 및 3∼5차례의 계대배양 후에도 이러한 모양은 계속 유지되었다. 충분히 자란 dish를 1 : 2로 계대배양을 한 후 다시 confluent하게 자라는 데에 걸리는 시간(doubling time)은 빠른 경우 84시간으로 나타났다. 분리 된 토끼 ES cell은 gelatin이 coating되지 않은 culture dish에 이식 배양하였을 때 부유상태로 증식하면서 내부에 강이 생기고 외배엽과 내배엽이 형성하는 전형적인 Embryoid body 모양을 나타내어 분리된 ES cell이 미분화상태의 stem cell임이 확인되었다. 본 연구를 통해 토끼에서의 수정란 배양을 통해 토끼 배아세포를 분리하여 특성을 규명하였다 현재까지의 연구성과로는 토끼 수정란의 배양기술을 완벽하게 개발했다는 점과 토끼에서 ES cell을 분리하여 앞으로 유전자 조작의 가능성을 열어 놓은 것이다. 토끼 ES cell system이 완벽히 확립되도록 분리된 ES cell에 대한 미분화상태의 연구 및 미분화상태를 식별할 수 있는 marker등에 대한 연구에 이용될 것이고 복제토끼 및 형질전환토끼의 생산 등을 위한 연구에 이용될 수 있다.

• Journal of Plant Biotechnology
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• 제44권3호
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• pp.287-295
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• 2017

Water temperature is one of the major factors that impacts the growth and life cycle of Pyropia tenera, one of the most valuable and cultivated marine red algae belonging to Bangiales (Rhodophytes). We analyzed transcriptome from gametophyte of P. tenera under normal and high temperature conditions, and identified four small heat shock proteins (sHSPs). They have no significant amino acid sequence homology with known proteins in public databases except PhsHSP22 from Pyropia haitanensis. PtsHSP19.3 gene responded to high temperature but slightly or not to desiccation, freezing or high salt condition. When the PtsHSP19.3 gene was overexpressed in Chlamydomonas reinhardtii, transformed Chlamydomonas lines revealed much higher growth rate than that of control cells under heat stress condition. Transformed cells also grew well in those of the control cell onto the medium containing high salt or $H_2O_2$. When the PtsHSP19.3 was fused to GFP and introduced into tobacco protoplast, fluorescence was detected at several spots. Results indicate that PtsHSP19.3 may form super-molecular assembles and be involved in tolerance to heat stress.

• 대한수의학회지
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• 제41권1호
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• pp.89-98
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• 2001

This study was conducted to detect the toxoplasma specific-DNA in circulating blood and organs collected from slaughtered pigs at slaughtering house and experimentally infected pigs with Toxoplasma gondii tachyzoites by polymerase chain reaction(PCR), and also PCR was applied to diagnose for acute phase of swine toxoplasmosis as a newly developed diagnostic test. The sensitivity of oligonucleotide primer, T-1 & T-2, designed from toxoplasma B1 gene amplification method was compared with Tp parasite detection by mouse inoculation(MI). On the other hand, latex agglutination test(LAT) was conducted to detect the serum antibodies comparing with the detection of toxoplasma by PCR and MI. The results obtained were summarized as follows. PCR was able to determine at the lowest level of $10^0/ml$ T. gondii in blood samples which were blended with a serial diluted T gondii in vitro. On the other hand, $10^2/5g$ of T gondii could detect from a variety of tissues including lung, diaphragm, liver, heart, spleen and brain in vitro. The primer was proved to specifically determine T gondii in blood and tissues in vitro but it did not detect Neospora caninum used as a negative control. DNA of T. gondii was effectively extracted by freezing, thawing and grinding twice both tissues mixed with T gondii in vitro and in experimentally infected pig's tissues. PCR detected specific DNA in the blood of experimentally infected pigs at 108 hrs and 120 hrs post-infection, it was the same time that the pigs showed fever and parasitaemia. In case of tissue, specific DNA was, however, detected only lung from experimentally infected pigs. Even though the duration of acute phase was from 3 to 7 days post-infection, but the latex agglutination test (LAT) results appeared from 8 days post-infection. A comparison of sensitivity in determining T gondii in blood samples between PCR and MI, PCR positive rate ranged from 25 to 33.3%, but that of MI covered from 75 to 100%.

• 한국수정란이식학회지
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• 제23권2호
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• pp.115-118
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• 2008

Glycerol is the cryoprotectant most frequently used to freeze semen in several of species. The objective of the present study was to compare the effect of three different glycerol concentrations (4, 6 or 8%, v/v) on frozen-thawed dog sperm survival rate. Ejaculates from 9 dogs collected by digital manipulation were pooled and assessed by macroscopic and microscopic criteria. Semen was divided into 3 aliquots, which were centrifuged and the sperm pellets rediluted with first Tris-glucose-citric acid extender. After 1 h cooling at $4^{\circ}C$, second extender containing 4, 6 or 8% glycerol was added, respectively. The semen was loaded into 0.25 ml straws and frozen and stored in liquid nitrogen and thawed. Sperm vigor, live:dead spermatozoa ratio using HOS test, and sperm morphology using $Spermac^{(R)}$ stain were evaluated. After thawing, there were no significant differences among groups in vigor, viability and morphology. In conclusion, the three glycerol concentrations (4, 6 or 8%) can be used successfully in cryopreservation of canine semen. Therefore the use of 4% glycerol in the extender has less toxic effect and reduces of freezing injuries.

• 한국식품조리과학회지
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• 제25권1호
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• pp.62-73
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• 2009

This study was conducted to evaluate the performance of sanitation management within school foodservice facilities and utilities in Gyeongbuk province. Data collection was carried out through surveys given to 200 school dietitians from the province. A total of 108 were usable, resulting in a 54.0% response rate. Statistical analyses were done using the SAS package program (version 8.2 for Windows). Of the study population, 58.3% had more than 10 years of work experience, and 64.8% worked in elementary schools. With regard to the style of foodservice system, 47.2% were urban and 46.3% were rural. Also, 89.8% of the school foodservices provided meals once a day. The performance of the sanitation management items of the facilities and utilities used to provide school foodservice was evaluated using a 5-point Likert scale. The average score for the 25 items was 3.35 points. 'HVAC system installed in foodservice establishment' had the lowest average score at 2.20 points. Whereas 'provide adequate storage capacity to allow refrigerating and freezing and an adequate thermometer is installed and temperatures monitored' had the highest average score at 4.19 points. Nine out of the 25 items were lower than the average score. The performance scores of high schools were significantly higher than those of elementary schools or middle schools for 'window materials are provided that are not liable to break' (p<0.001). The performance scores for urban style foodservices were significantly lower than for rural foodservices for 'floor of kitchen is constructed to maintain a dry system' (p<0.05). In response to questions on kitchen utensils and equipment, significant differences were shown according to the number of meals served per day in 21 out of 56 items, and the style of foodservice system showed significant differences in 14 of the 56 items. Foremost, to make better use of the foodservice facilities and utilities in Gyeongbuk province, immediate improvements should be made for management items in which the degree of performance was below the average score.