• Food Science of Animal Resources
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• v.20 no.4
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• pp.282-287
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• 2000

동결기간과 해동 후 재냉장이 우육의 기호성에 미치는 영향을 검토하기 위하여 도축 후 1일 냉장한 홀 스타인 등심육을- 2$0^{\circ}C$에 동결하여 20, 40 및 60일째에 해동하는것과 이것을 1$^{\circ}C$에 재냉장한 것의 전단력가, 부수성, 액토미 오신의 추출성과 ATPase 활성에 대한 실험과 함께 관능평가를 실시하였다. 우육의 전단력가능 동결 중 변화가 없었으며 해동 후 재냉장에 의하여 낮아졌다. 부수성은 동결기간이 길수록 낮아지고 재냉장에 의한 유의적인 차이를 보이지 않았다. 액토미오산의 추출성과 Ma-ATP-ase 활성은 동결기간이 길수록 낮아지고 재냉장에 의하여 높아지고 경향을 보였다. 재냉장에 의한 기홍성 향상 효과는 동결기간이 짧을수록 크게 나타났다. 재냉장에 의하여 기호성이 우수하게 된 것은 조직감과 가열육향의 향상이 크게 관련되었다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.91-95
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• 1978

Histological changes of the abalone muscle occurring in the process of freezing as well as thawing were investigated, and its results were compared to the histological structure of fresh muscle. The muscles of the abalone were mainly composed of smooth muscle fibres, and its morphological structures is similar to those of the top shell. Mechanical damgage of the muscle fibres caused by freezing were not observed while a number of small ice crystals were found between the muscle fibres. The damage by thawing was not much remakable compare to the destruction of muscle fibres of fish.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.4
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• pp.307-319
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• 2010

Objective: Vitrification requires a high concentration of cyroprotectant (CPA) and an elevated cooling speed to avoid ice crystal formation. We have evaluated the effect of different combinations of cooling rate and CPA on embryonic integrity (developmental competence) in order to increase the efficiency of vitrification without impairing embryo viabilit. We hypothesized that the combination of CPA or the increase of cooling rates can reduce the concentration of toxic CPA for vitrification. As consequently, we performed experiments to evaluate the effect of various composition of CPA or slush nitrogen ($SN_2$) on the mouse embryonic development following vitrification using low CPA concentration. Methods: Vitrification of mouse embryos was performed with EM grid using liquid nitrogen ($LN_2$) or $SN_2$ and different composition of CPAs, ethylene glycol (EG) and dimethylsulfoxide (DMSO). After vitrification-warming process, their survival and blastocyst formation rates were examined. For analyzing long-term effect, these blastocysts were transferred into the uterus of foster mothers. Results: Survival and blastocyst formation rates of vitrified embryos were higher in EG+DMSO group than those in EG only. Furthermor, the group using $SN_2$ with a lower CPA concentration showed a higher survival of embryos and developmental rates than group using $LN_2$. Conclusion: The combination of EG and DMSO as CPAs may enhance the survival of mouse embryos and further embryonic development after vitrification. $SN_2$ can generate high survival and developmental rate of vitrified/warmed mouse embryos when a lower concentration of CPA was applied. Therefore, these systems may contribute in the improvement of cryopreservation for fertility preservation.

• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.186-187
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• 1995

동결보존에서 가장 재생율이 높은 품종은 조직배양에서 발근력이 뛰어난 것으로 알려져 있는 신광뽕으로 최고 92.0%의 재생율을 보였으나, 개량, 용천 및 검설뽕에서는 재생을 보이지 않았다. 또, 건조과정을 거치지 않은 것이나, 건조과정과 예비동결 과정을 거치지 않고, 동결방어제만을 사용한 것의 재생은 전혀 확인할 수 없었다. 금후, 동결보존한 동아의 재생에서 돌연변이 유무는 RAPD로 확인될 수 있을 것이다.

• Journal of Embryo Transfer
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• v.18 no.1
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• pp.43-50
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• 2003

The objective of this study was to investigate the effect of cryopreservation by slow and rapid freezing on the sperm motility index, viability and morphology of post-thaw human spermatozoa. After rapid freezing and thawing, sperm motility index was significantly higher (MOT:47.40$\pm$20.06%, VCL : 38.12$\pm$15.58 $\mu$m/s, VSL : 28.19$\pm$14.10 $\mu$m/s, VAP:33.64$\pm$15.15 $\mu$m/s, and HYP 2.77$\pm$2.71%) than slow freezing and thawing(MOT : 43.39$\pm$ 18.79%, VCL .33.91 $\pm$ 13.50 Um/s, VSL . 19.98$\pm$0.88 $\mu$m/s, VAP : 24.60$\pm$11.72 $\mu$m/s, and HYP . 1.33$\pm$1.57% ; P<0.05). But sperm Linearity(LIN) was significantly lower(28.83 $\pm$ 10.35) comparing to the slow freezing method(34.64 $\pm$ 11.36 ; P<0.05). On the other hand, significant difference were not observed MAD, WOB, DNC and DNM by slow and rapid frozen-thawed methods. After rapid freezing and thawing, sperm viability was lower(60 $\pm$ 2.2%) than slow freezing method(62 $\pm$2.1%) and sperm morphology was higher(46$\pm$7.7%) than that(44: 8.3). But there was no significantly These results indicate that rapid freezing method was positive effect of sperm cryopreservation in human.

• Journal of the Korea Concrete Institute
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• v.15 no.1
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• pp.43-51
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• 2003

Recently, to consider financial and constructive aspect usage of Admixture such as Blast-Furnace Slag and Fly-Ash, are increased. Also the use of cold-weather-concrete is increased. Blast-Furnace Slag, a by-product of steel industry, have many advantage to reduce the heat of hydration, increase in ultimate strength and etc. But it also reduces early-age strength, so it is prevented from using of Blast-Furnace Slag at cold-weather-concrete. In this study, for the purpose of increasing usage of Blast-Furnace Slag at cold-weather-concrete, it is investigated the strength properties of concrete subjected to frost damage for the cause of early age curing. The factors of this experience to give early frost damaged were Freezing temperature(-1, -10, $-15^{\circ}C$), Early curing age(0, 12, 24, 48hour), Freezing times(0, 12, 24, 48hour). According to this study, if early curing is carried out before haying frost damage, the strength of concrete used admixture, subjected to frost damage, is recovered. And that properties are considered, the effect of using admixture like blast-furnace-slag, is very high

• Journal of the Korean GEO-environmental Society
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• v.10 no.4
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• pp.15-24
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• 2009

Korea is known to have seasonal frost during winter and the effect of low temperatures and water may cause a weakening of pavements. For that reason, frost protection layers have been constructed in pavements to avoid damage caused by frost action. The practies established in USA and Japan have been adopted as anti-frost design methods in Korea. However, the characteristics of Korean soils are different. Additionally, there is no formulation of a reasonable equation for frost penetration depth and the criterion to identify potentially frost-susceptible soils in present pavement design manuals in Korea. Therefore, adequate pavement design procedures in seasonal frost areas, as well as construction and maintenance practices are required. In this paper, frost penetration depths along national roads in Korea were measured and analyzed over several years. The frost penetration depth was analyzed with respect to the provinces of Korea and sunny/ shaded areas. Additionally, measurement results were compared to the formula of the US Army Corps of Engineers and Ifukube in Japan.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.820-826
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• 1988

The freezing point$(t_f)$, latent heat of freezing$({\triangle}\;H_f)$ and kinetic constant of fleering$(k_f)$ were determined from DSC thermogram at cooling rate $-2.5^{\circ}C/min{\sim}-10.0^{\circ}C/min$. The freezing point of various starches was decreased with an increase in cooling rate, and that of whole starches were lower than defatted starches. Changes of the latent heat of freezing was not observed at above cooling rate $-2.5^{\circ}C/min$. The latent heat of freezing$({\triangle}\;H_f)$ could be deduced as a function of water content(W) as follows: ${\triangle}\;H_f=0.700W-13.048$, (Kcal/kg) $(35%{\leqq}W{\leqq}70%)\;{\triangle}\;H_f=1.569W-73.861,\;(Kcal/kg)\;(W{\geqq}70%$) In the water content range $35{\sim}90$(wt %), the activation energy of various starches in freezing process was determined $126{\sim}270$ Kcal/mol.

• Journal of Animal Science and Technology
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• v.55 no.5
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• pp.417-425
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• 2013

We sought to provide a method for freezing and preserving primordial germ cells, or an avian germ cell of a bird, as a material for developmental engineering or species preservation. The aim of this study was to compare the efficacy of slow freezing with a vitrification method for the cryopreservation of chicken primordial germ cells (PGCs). PGCs obtained from the germinal gonad of day 5.5-6 day (stage 28) cultured chick embryos, using the MACS method, were classified into two groups: slow freezing and vitrification. We examined the viability of PGCs after Cryopreservation. Four freezing methods were compared with each other, including the following: Method 1: The PGCs were frozen by a programmed freezer in a plastic straw, including 2.0 M ethylene glycol (EG) as cryoprotective additive (slow freezing) Method 2: The PGCs were vitrified in a plastic straw, including 8.0 M EG, plus 7% polyvinylpyrrolidone (PVP) (rapid freezing). Method 3: The slow freezing was induced with a cryotube including 2.0 M EG Method 4: The PGCs were frozen in a cryotube including 10% dimethyl suloxide (DMSO) (rapid freezing). After freezing and thawing, survival rates of the frozen-thawed PGCs from Method 1 to 4were 76.4%, 70.6%, 80.5% and 78.1% (p<0.05), respectively. The slow freezing ($-80^{\circ}C$ programmed freezer) method may provide better survival rates of frozen-thawed PGCs than the vitrification method for the cryopreservation of PGCs. Therefore, these systems may contribute to the cryopreservation of a rare avian species.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1448-1455
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• 1998

Fermented milk was prepared from milk or mixture of milk and apple juice/grape juice, and it was freeze dried. pH change and growth of Lactobacillus acidophilus (KCTC 2182) during freeze drying were studied. The effects of freeze drying on sensory evaluation and volatile aroma compounds in freeze dried sample or reconstituted sample were also studied. Freezing and freeze drying did not affect pH of fermented milk. Number of viable cells of L. acidophilus was markedly reduced during freezing or freeze drying. When number of viable cells in original fermented milk was considered as 100%, survival ratio of viable cells after freezing was $64.5{\sim}85.2%$ and that after freeze drying was $10.0{\sim}21.1%$. When sensory properties of original fermented milk prepared from juice-milk (ratio 15:35) were compared with those of freeze dried/reconstituted sample, sensory properties of original sample were better than those of freeze dried/reconstituted sample. Ethanol, diacetyl, butanol and acetoin were detected in all of original samples and freeze dried/reconstituted samples while acetone was detected in samples containing high amount of grape juice. Volatile aroma compounds in original fermented milk were reduced during freeze drying. L. acidophilus produced ethanol, diacetyl and acetoin during fermentation.