• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제22권3호
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• pp.262-269
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• 2019

Purpose: As the importance of breastfeeding has been reinforced, human milk is often stored for practical reasons. Therefore, we evaluated optimal storage and processing methods for human milk from a nutritional standpoint. Methods: Human milk samples were collected between June 2017 and February 2018. Also, data about maternal information were collected. Human milk was analyzed for macronutrients and caloric content. The samples were subdivided into groups for nutrient analysis. The control group (fresh milk) was not stored or processed. The other groups (9 groups) consisted of samples analyzed based on different storage temperatures (room temperature, refrigerated, frozen), defrosting methods (bottle warmer, room temperature thawing, microwave oven), and storage period (1 week, 1 month, 2 months) and compared with the control group. Results: There was no statistically significant difference in the nutrient content of human milk among the collected samples. A significant change in the content of macronutrients in milk samples was observed under storage condition at different temperatures for 1 week with subsequent thawing with bottle warmer compared to fresh milk. Under storage at $-20^{\circ}C$ for 1 week with subsequent thawing with different defrosting methods, a significant change in the content of macronutrients in milk samples was observed compared to fresh milk. After storage at $-20^{\circ}C$ for different periods and thawing with a bottle warmer, a significant change in macronutrient content in milk samples was observed compared to fresh milk regardless of the storage period. Conclusion: Unlike previous guidelines, changes in macronutrient content in milk samples were observed regardless of the method of storing and thawing. Apparently, it is proposed that mothers should feed fresh human milk to their babies without storing.

• 한국동물생명공학회지
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• 제39권2호
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• pp.88-94
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• 2024

Background: Using cryovial for freezing dog spermatozoa provides a practical method to increase extended sperm volume and shorten the time required for equilibration by using a simple freezing techniques. The purpose of this study was to determine the optimal thawing condition for dog sperm cryopreservation using cryovials. Methods: For sperm freezing, cryovials with 200 × 10⁶ sperm/mL were cooled after the addition of tris egg yolk extender (TEY) at 4℃ for 20 min, then TEY with 4% glycerol was added and equilibrated for another 20 min before being aligned over LN₂ vapor for another 20 min and plunged directly into LN₂. Spermatozoa were thawed in a water bath at 37℃ for varying times (25 sec, 60 sec, 90 sec, and 120 sec) in the first experiment. In the second experiment, spermatozoa were thawed in a water bath at various temperatures and times (37℃ for 1 min, 37℃ for 1 min with gentle stirring, 24℃ for 24 min, and 75℃ for 20 sec). In these experiments, the effect of thawing conditions on motility parameters, viability (SYBR-14/PI), and acrosome integrity (PSA/FITC) of spermatozoa were investigated. Results: The post-thaw sperm motility parameters, viability, and acrosome integrity were not significantly different across the experimental groups. Conclusions: In this study, the characteristics of spermatozoa frozen using cryovials were not significantly affected by various thawing conditions.

• Clinical and Experimental Reproductive Medicine
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• 제39권4호
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• pp.153-160
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• 2012

Objective: The aim of this study was to compare vitrification optimization of mouse embryos using electron microscopy (EM) grid, cryotop, and thin plastic strip (TPS) containers by evaluating developmental competence and apoptosis rates. Methods: Mouse embryos were obtained from superovulated mice. Mouse cleavage-stage, expanded, hatching-stage, and hatched-stage embryos were cryopreserved in EM grid, cryotop, and TPS containers by vitrification in 15% ethylene glycol, 15% dimethylsulfoxide, 10 ${\mu}g/mL$ Ficoll, and 0.65 M sucrose, and 20% serum substitute supplement (SSS) with basal medium, respectively. For the three groups in which the embryos were thawed in the EM grid, cryotop, and TPS containers, the thawing solution consisted of 0.25 M sucrose, 0.125 M sucrose, and 20% SSS with basal medium, respectively. Rates of survival, re-expansion, reaching the hatched stage, and apoptosis after thawing were compared among the three groups. Results: Developmental competence after thawing of vitrified expanded and hatching-stage blastocysts using cryotop and TPS methods were significantly higher than survival using the EM grid (p<0.05). Also, apoptosis positive nuclei rates after thawing of vitrified expanded blastocysts using cryotop and TPS were significantly lower than when using the EM grid (p<0.05). Conclusion: The TPS vitrification method has the advantages of achieving a high developmental ability and effective preservation.

• 한국가금학회지
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• 제46권4호
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• pp.223-234
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• 2019

This study investigated the effects of thawing methods and storage time on the quality of frozen duck meat. Meat was obtained from eight-week-old Korean native ducks (average weight=2.8 kg). Seventy-two samples were divided into eight treatments (three replicates/treatment, three samples/replicate) with 2 × 4 factorial arrangement based on two thawing methods (under running water at 12℃ for 3 h and in a refrigerator at 5℃ for 24 h) and four storage times (1, 3, 6, and 12 months). CIE b^* was significantly different among different storage time treatments, reaching its lowest after 6 months (P<0.05). Cooking loss did not differ between storage times; however, it was significantly lower following application of the fast thawing treatment (P<0.05). Water-holding capacity of meat stored for one month was highest compared to that of meat stored for a longer period (P<0.05). Additionally, there were significant differences based on storage time in γ-linoleic acid (C18:3n6) and eicosenoic acid (C20:1n9) contents (P<0.01), as well as in protein contents (P<0.05). Palmitoleic acid (C16:1n7) typically decreased after three months of storage; however, this decline was not significant compared to other storage times. Essential amino acids contents, except methionine, were significantly difference at six and 12 months of storage (P<0.05). Similarly, non-essential amino acid contents, except tyrosine, were significantly different among storage periods (P<0.05, P<0.01). Alternatively, there were no significant differences in the chemical composition, fatty acid content, or amino acid content based on the thawing method.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.589-592
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• 2008

이 연구는 겨울철 동결융해 작용으로 인한 차염성 저발열시멘트(CLC)의 내구성을 알아보고자 수행하였다. 내구성 문제는 현장여건에 따라 다소 차이는 있으나, 계절변화에 따른 반복적인 동결융해작용에 의한 콘크리트의 동해는 내구성 저하의 대표적 현상이라 할 수 있으며, 겨울철 동결융해를 받는 콘크리트는 내부에서 큰 팽창력이 발생되어 콘크리트 균열, 표면 박리, 골재 이탈 등의 파손현상을 보이게 된다. 따라서 이 연구에서는 개발된 차염성 저발열시멘트(CLC)의 동결융해 저항성에 따른 내구성 지수를 알아보기 위해 차염성 저발열시멘트(CLC)와 현재 많이 사용되고 있는 고로슬래그시멘트(BFS), 보통 포틀랜드시멘트(OPC)을 각각 물/시멘트비 35%, 40%, 45% 을 변수로 하여 배합을 실시 하여 공시체를 제작하였다. 제작된 공시체를 KS F 2456(급속동결 융해에 대한 콘크리트의 저항 시험방법)방법에 따라 동결융해 시험을 실시하여 상대 동탄성 계수를 측정하였으며, 측정된 상대동탄성 계수를 가지고 내구성지수를 도출하였다. 내구성 지수를 비교 분석한 결과 차염성 저발열시멘트(CLC), 고로슬래그 시멘트(BFS), 보통 포틀랜드 시멘트(OPC) 모두 우수한 내구성 지수를 나타내는 것으로 확인 되었다.

• 한국가축번식학회지
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• 제26권2호
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• pp.119-124
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• 2002

본 연구는 돼지에서 동결정액을 이용한 번식능력을 개선하기 위한 동결정액 포장재료의 효과를 구명하기 위하여 실시하였다. 본 시험에는 축산기술연구소 종축개량부 (충남, 성환)의 인공수정센터에서 사육중인 종모돈이 사용되었다. 기존의 돼지 동결정액 포장방법인 maxi-straw 동결정액 포장방법과 5$m\ell$빈 cryogenic-vial 및 aluminum-pack 포장방법을 비교한 결과 cryogenic-vial로 포장하여 액체질소 상단 15cm에서 동결한 후 52$^{\circ}C$ water bath에서 190초 융해한 방법이 기존의 maxi-straw 방법과 비슷한 결과를 나타내었다. Cyogenic-vial 포장방법의 동결-응해 방법을 설정하기 위하여 융해시간을 달리하여 시험한 결과 액체질소 상단 15cm에서 동결하고 52$^{\circ}C$에서 190초 간 융해하였을 때 정자운동성이 120초 및 150초 응해시 보다 우수하였다 (P<0.05). 그러나 정상첨체비율은 응해시간 간에 차이가 없었다. 52$^{\circ}C$에서 45초간 응해 한 maxi-straw 포장방법과 52$^{\circ}C$에서 190초 융해한 cryogenic-vial 포장방법간에 정액성상을 비교한 결과 총정자운동성과 정자의 빠르기는 maxi-straw가 우수하였다 (P<0.05). 그러나 직진성과 정상첨체비율은 두 포장방법간에 차이가 없었다. 동결정액 포장방법별 인공수정시 번식성적은 maxi-straw 동결정액이 cryogenic-vial 동결정 액보다 수태율, 분만율, 그리고 산자수가 높았으나 통계적 유의차는 인정되지 않았다. 이상의 결과를 종합해 보면 cryogenic-vial 포장 방법의 동결 및 음해방법을 좀 더 연구개발하면 기존의 maxi-straw포장방법을 대체하여 실용화 할 수 있을 것으로 사료된다.

• 한국식품저장유통학회지
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• 제18권3호
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• pp.302-309
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• 2011

본 연구는 오가피순과 두릅의 소비 확대와 가공품 개발의 전처리로 필수적인 blanching 조건을 설정하기 위해 blanching 온도와 식염의 농도에 따른 품질 변화와 관능적 특성을 평가하고자 하였다. 또한 해동조건에 따른 이화학적 및 관능적 특성을 평가하여 오가피순과 두릅의 품질을 향상시킬 수 해동조건을 설정하고자 하였다. Blanching은 식염 첨가량(무첨가, 1%, 2% 첨가)과 blanching 시간(4분, 7분)을 달리하였으며, 해동방법은 저온($4^{\circ}C$), 상온($25^{\circ}C$) 및 microwave를 이용하여 해동하였다. Blanching 조건에 따른 색도, chlorophyll 함량, texture 측정 및 관능검사를 실시한 결과, 오가피순과 두릅은 식염첨가 없이 $95^{\circ}C$에서 4분간 blanching한 경우 품질 변화와 기호도가 가장 높게 나타났다. 해동방법에 따른 품질 특성 및 관능검시를 실시한 결과, 오가피순과 두릅은 각각 상온 해동과 microwave 해동에서 가장 높은 품질과 기호도를 나타내었다.

• Clinical and Experimental Reproductive Medicine
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• 제19권2호
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• pp.143-152
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• 1992

The present experiments were focussed to modify a short slow-cooling protocol used for freezing of early stage embryo(Testart et al., 1986) and also to apply the modified method for the cryopreservation of hamster oocytes with Zona or without. The protocol was modified by changing the 4-step equilibration into 1-step and the 1-step thawing into 2-step. The oocytes were added in 1.5M PROH and 0.1M Sucrose, seeded at $-7^{\circ}C$, slow cooled($0.3^{\circ}C$/min) to $-30^{\circ}C$ before plunging to $-196^{\circ}C$. The oocytes were thawed at $23-25^{\circ}C$ air(20sec/150sec) and/or 33-35 water(10sec). The survival of the frozen-thawed oocytes was determined by morphologic criteria and their fertilizing ability was also estimated by Sperm Penetration Assay(SPA) system(Chang et al, 1990) using fertile men semen sample. One-step equilibration showed slightly higher survival rate(83.9% vs. 71.0%) and fertilization rate(83.9% vs. 71.0%) compared with four-step(p>0.05). And two-step thawing(air & water exposing) of oocytes frozen after 1-step equilibration showed significantly higher survival rate(96.3%) than one-step thawing at air(85.2%) or water(65.0%) only(p<0.05). Therefore, by the modified method(l-step equilibration & 2-step thawing), Zona-intact(ZI) and Zona-free(ZF) oocytes were frozen and thawed. ZI-oocytes showed significantly higher survival rate(95.4%, 308/323 vs. 67.6%, 240/355) than ZF-oocytes(P<0.01). But the survival of ZF-oocytes was as high as ZI-oocytes in fourteen of twenty-four replicates. ZI-oocytes was also significantly higher fertilization rate($92.4{\pm}8.9%$ vs. $63.7{\pm}18.5%$) and higher mean number of penetrated sperm($6.2{\pm}4.2$ vs. $3.9{\\pm}3.3$) than ZF-oocytes, but not higher than control(fresh oocytes;$99.3{\pm}2.4%$, $8.4{\pm}4.2$)(P<0.001). Conclusively, this modified method will contribute to freeze effectively the hamster oocytes for simplifing of the logical consideration of performing SPA and also to freeze the human and other animal oocytes.

• 한국수정란이식학회지
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• 제4권1호
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• pp.1-13
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• 1989

This paper reviews the most important steps that have generated consistent progress in principles and developmental progress of embryo cryopreservation, and also study on freezing procedure and its application by conventional method and current improved method for freezing procedure and its appilcation of embryo cryopreservation in farm animals. Four were of particular interest: 1.The transport of water across the ccli membrane (zona pellucida) during freezing and thawing accordinglyplays a role in determing whether the celi survives. This movement of water is controlied mainly by extracellular phase changes and by the nature and concentration of any cryoprotective agent present. Therates of cooling, freezing and warming, and the intervals over which they are applied are further decisi've factors in determining whether a cryopreservation procedure allows survival after thawing. 2.The first successful deep freezing experiments with sheep morula and blastocysts during the seventies were based on the early procedures used for mouse embryos.Current research during the eighties is developed with the aim of simplifying and improving current procedures such as one-step dilution and rapid or ultra-rapid cooling by using the model of laboratory animals. 3.The conventional method for the embryo cryopreservation is described. An alternative to this method which may result in high survival and also in reducing of the freezing and thawing time is done by combing a permeable cryoprotectant such as glycerol, DMSO or propanediol and a non-permeable compound such as sucrose, trehalose, raffinose or lactose. 4.Finally a different approach to the preservation of embryos, named vitrification, is introduced. This procedure depends upon the ability of concentrated solutions of cryoprotective agents such as glycerol and propanediol to supercool to very low temperature (-196$^{\circ}C$) during rapid cooling before solidifying without formation of ice. However, more complete data are necessary for successful vitrification of blastocysts.

• 한국수정란이식학회지
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• 제23권1호
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• pp.19-24
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• 2008

The purpose of this study was to compare the efficiency of slow freezing with that of vitrification method for the cryopreservation of human embryos. Human embryos were derived from in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and the mixed solution of propanedial (1.5, 1.0, 0.5M PROH) and sucrose (0.1M), ethylene glycol (7.5, 15%), dimethyl sulfoxide (7.5, 15% DMSO), sucrose (0.5, 1.0M) and SPS (Serum Protein Substitute) was used for a cryoprotectant for slow freezing and vitrification solution, respectively. Rates of recovery after thawing, morphological normality, post-thaw viability, arrest, morphological abnormality and preimplantation development were compared between two protocols. After freezing-thawing, recovery and survial rate of slow freezing was (88.6% and 73.4%), whereas vitrification was (99.2% and 96.2%) (p<0.05). The arrest rate of slow freezing was significantly lower compared with those of vitrification(8.7% vs 29.9%) (p<0.05). Preimplantation development to the 2-cell (83.8% vs 67.7%), 4-cell (69.0% vs 47.2%) and 8-cell (62.4% vs 37.8%) stages 24, 48 and 72 h after thawing, respectively, were higher in the slow freezing than the vitrification. After slow freezing and vitrification of human embryo at 2-8cell stage, the rate of recovery rate, survival rate and partial damage rate were 92.0% vs 100%, 80.4% vs 96.2% and 52.2% vs 19.0%, respectively. And partial damage rate was significantly lower than those of slow freezing method (p<0.05). These results demonstrate that a slow freezing using PROH is more efficient than a vitrification for cryopreserving the human zygotes, although the vitrification yielded better recovery, survival and partial damage of frozen-thawed 2-8 cell stage embryos than slow freezing method.