• 한국식품과학회지
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• 제32권2호
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• pp.335-340
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• 2000

연시 및 puree의 냉동저장중 품질변화와 puree의 갈변방지를 위한 ascorbic acid첨가 및 데치기 처리효과에 관한 결과는 다음과 같았다. 총 carotenoid, 환원당 및 가용성 고형분 함량은 저장 중 별다른 변화를 보이지 않았으나, ascorbic acid함량은 저장기간이 경과함에 따라 지속적으로 감소하였다. 청도반시의 경우 저장 중 저온 및 microwave oven을 사용해 해동할 경우, 해동 방법에 따른 품질 특성의 차이를 보이지 않았다. 한편, puree의 점도는 해동 후 급격히 저하되는 경향을 보였으며, Hunter L, a, b값은 지속적으로 감소하여 모든 시료에서 갈변되는 경향을 보였으나, ascorbic acid를 첨가함으로써 갈변현상이 지연되었다. 반면, puree를 데치기 하였을 때 변색과 gel화에 따른 급격한 점도의 증가를 유발함에 따라 갈변 억제 수단으로써 실용성이 없는 것으로 판단된다.

• Clinical and Experimental Reproductive Medicine
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• 제32권2호
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• pp.91-99
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• 2005

Objective: To define an appropriate vitrification condition of preantral follicle that yields high survival and to evaluate growth and ovulation rate of mouse follicles during in vitro culture after vitrification. Methods: Preantral follicles were isolated mechanically from mouse ovaries that were surgically recovered from mice aged 14 days. Retrieved preantral follicles were placed in EG (Ethylene Glycol) for 2, 5, 10 minutes and transferred to EFS-40 (40% EG, 18% Ficoll-70, 0.5 M sucrose) for 0.5, 1, 2 minutes. And then, preantral follicles were placed onto an EM grid and submerged immediately in liquid nitrogen. Thawing was carried out at room temperature. After defining the most appropriate vitrification condition that yields high survival, in vitro growth and ovulation rate of follicles were evaluated. Results: Appropriate vitrification condition that yield high survival rate ($83.2{\pm}2.1%$) of preantral follicle was EG for 5 minutes and EFS-40 for 0.5 minutes. In vitro survival rate of the vitrified preantral follicles were $85.5{\pm}0.5%$, $67.9{\pm}0.8%$ and $40.2{\pm}0.5%$ on day 2, 6 and 10. And in vitro growth of the vitrified preantral follicles were $107.1{\pm}16.1{\mu}m$, $117.1{\pm}18.4{\mu}m$, $178.4{\pm}45.6{\mu}m$ and $325.4{\pm}54.4{\mu}m$ on day 0, 2, 6 and 10. Although in vitro survival rate and growth of vitrified preantral follicles were lower than that of non-vitrified preantral follicles, the patterns of survival and growth were similar in vitrified and non-vitrified preantral follicles. The ovulation rate of antral follicles that was grown from vitrified preantral follicles was $32.6{\pm}1.2%$. Conclusion: Vitrified preantral follicles could be grown to antral sizes, and mature oocytes that can be used for IVF-ET programs were produced successfully. These data suggest that cryopreservation of preantral follicle by vitrification can be used for the preservation of the fertility.

• 한국건축시공학회지
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• 제19권4호
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• pp.307-312
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• 2019

레미콘 제조 시 발생되는 슬러지는 폐기물로 분류되어 높은 비용을 지불하며 처리를 하고 있다. 특히 중소레미콘 업체에서는 이 비용이 큰 부담으로 작용되며, 일부 업체에서는 불법적인 처리가 발생되고 있는 실정이다. 따라서 본 연구에서는 레미콘슬러지를 콘크리트블록용 조성물로 재활용하는 방법을 제시 하는데 그 목적이 있다. 레미콘슬러지를 단순 건조하여 사용 하였을 때에는 슬러지에 포함된 잔류화학혼화제와 에트린가이트가 존재하여 콘크리트블록의 압축강도, 동결융해 후 압축강도 물리적성능이 크게 떨어져 콘크리트호안 및 옹벽블록의 품질기준을 만족하지 못하는 것으로 나타났다. 물리적 성능을 만족시키기 위한 방법으로 레미콘슬러지를 $900^{\circ}C$정도의 고온에서 소성시켜 에트린가이트와 잔류 화학혼화제 등을 분해시킨 후 사용하는 것이 우수한 것으로 나타났다.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
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• pp.73-73
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• 2003

The present study examined the possibility of long term storage, by cryopreservation in liquid nitrogen, of the sperm of Filefish (Thamnaconus septentrionalis), and the changes in motility, survival rate and ultrastructure of the sperm after freezing and thawing. The sperm was collected by stripping and stored on ice until experiments. For selection of the immobilizing solution, diluted artificial seawater (ASW) of 20, 30 and 40% were tested. The sperm motility was significantly inhibited in 30% ASW, and restored entirely after 100% ASW was added again. Two cryoprotectants, dimethyl sulfoxide ($Me_2$SO) and glycerol, were added to 30% ASW to formulate the extenders at the concentrations between 5 to 20% by volume for freezing. The sperm was diluted at the ratio of 1 :6 with the extenders, inserted into 0.5ml plastic straws and frozen at a freezing rate of $50^{\circ}C$/min to $-100^{\circ}C$ after equilibration for 10 min at room temperature, followed by plunging into liquid nitrogen. The straws were thawed in a $30^{\circ}C$ water bath for 15 sec. The highest post-thawed sperm motility and survival rate were obtained with 5% glycerol Afterward, the effect of different freezing rates was examined using 5% glycerol as a cryoprotectant, and the rate of $20^{circ}C/min to $-80^{\circ}C$ showed the best result Some ultrastructural changes of sperm, such as the detachment of plasmatic and nuclear membranes, destruction of mitochondria, were observed after cryopreservation. Morphological normality of the sperm in 5% glycerol frozen at the ratio of 1$0^{\circ}C$/min to $-80^{\circ}C$ was better than that of others.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2023년도 임시총회 및 춘계학술대회
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• pp.33-33
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• 2023

Potatoes are the world's 4th major food crop after maize, rice, and wheat and also are a staple food for 1.3 billion people. Due to their wide adaptability to various environmental conditions, their yeild capacity, and high commercial value, potatoes have contributed to global food security. Many potato germplasms are commonly preserved as whole plants in fields or in storage to maintain their particular genetic combinations. However, field maintenance is expensive and has the risk of potential losses from diseases, pests, plant ageing and climate change. Over the past four decades, meaningful efforts have been made toward the safe long-term conservation of potatoes through cryopreservation methods such as droplet-vitrification. In this study, we tested 4 Korean potato varieties('Golden Egg', 'Golden Ball', 'Ja-Young' and 'Ha-Ryeong') with the modified potato droplet -vitrification protocol. Potato shoot tips are precultured in a sucrose-enriched medium(0.3 and 0.7M for 7 and 17hrs, respectively) and submitted to a loading step with C4 solution for osmoprotection. The treated explants were dehydrated with Plant Vitrification Solution(PVS)2 which is 80% A3 solution in ice for 30 minutes. Thawing and unloading steps were performed with 0.8M sucrose solution for 30 sec(40℃) followed by 30min(25℃, room temperature). In a potato post-culture medium(MS+0.1 mg·L^-1 GA₃+0.1 mg·L^-1 kinetin), we obtained a survival rates of post-thawed explants ranging 16.1-82.2%. The results suggest that modified and optimized protocols are required dependinig on every cultivar, genetic and ecological types. To achieve higher survival and regeneration rates, each step within the cryoprocedure must be carefully optimized.

• Restorative Dentistry and Endodontics
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• 제35권4호
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• pp.285-294
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• 2010

본 연구의 목적은 흰 쥐의 상악 대구치를 발거한 후 치주인대세포를 $0^{\circ}C$/2 MPa고압-저온하에 1주간 보관시켜 MTT, WST-1 검색법을 이용하여 측정한 치주인대세포의 활성도를 저속 냉동법(No Additional Pressure, 2, 3 MPa), 급속 냉동법(No Additional Pressure, 2 MPa), $-5^{\circ}C$/90 MPa초고압 저온보존법과 비교하여 평가하는 것이다. 생후 4주된 암컷 Sprague-Dawley계 흰쥐의 상악 좌우 제1, 2대구치를 발거하여 각 군 당 12개의 쥐 치아를 MTT, WST-1 검색에 이용하였다. 실험군은 9개군으로 대조군은 즉시 발치군이며, 각각 3 MPa, 2 MPa, No Additional Pressure (NAP)의 압력을 가한 후 $4^{\circ}C$에서 $-35^{\circ}C$까지 $-0.5^{\circ}C$/min 속도로 서서히 냉동시킨 뒤 $-196^{\circ}C$에 냉동한 저속 냉동군, 발치 후 동해방지제 처리과정을 거쳐 각각 2 MPa, NP의 압력을 가한 후, $-196^{\circ}C$의 액화질소에 넣어 냉동한 급속 냉동군, 발치 후 각각 2MPa,NP의 압력을 가한 후, $0^{\circ}C$에 보관한 저온 보존군, $-5^{\circ}C$/90 MPa의 초고압 저온 보존군으로 나누었다. 보존액은 F medium을 사용했으며 동해방지제로 10% dimethylsulfoxide (DMSO)를 사용하였다. 치근면을 단위면적으로 표준화하기 위해 MTT, WST-1 측정값을 Eosin 염색 후 530 nm에서 측정한 흡광도 값으로 나누었다. 통계 분석을 위해 one way ANOVA를 시행하였으며 사후 검정으로는 Tukey HSD 방법을 사용하였고 결과는 다음과 같다. 1. MTT 검색법 및 WST-1 검색법 결과 $0^{\circ}C$/2 MPa 고압 저온 보존군이 즉시 발치군보다 세포 활성도가 낮았으나 통계적 유의차는 없었으며, 저속 압력 냉동군(NP, 2 MPa, 3 MPa)과, 급속 압력 냉동군(NP, 2 MPa), 저온보존군($0^{\circ}C$/NP), 초고압 저온 보존군($-5^{\circ}C$/90 MPa)보다 통계적으로 유의차있게 높은 세포 활성도를 나타내었다(p < 0.05). 2. MTT검색법 및 WST-1 검색법 결과 $-5^{\circ}C$/90 MPa 초고압 저온 보존군이 가장 낮은 세포 활성도를 나타내었으며, MTT 검사 결과에서는 모든 군에 대해 통계적으로 유의성 있는 결과를 보였다(p < 0.05). 위의 결과를 통해, $0^{\circ}C$/2 MPa (20기압)의 고압-저온 보존법이 다른 급속 냉동 보관법(2 MPa, NAP)이나 저속냉동보관법(3, 2 MPa, NAP), $-5^{\circ}C$/90 MPa 초고압 저온 보존법에 비해 우수한 쥐 치아의 치주인대세포의 활성도를 보여 차후 치아의 재이식시 치아보관을 위한 방법으로의 가능성을 제시하였다.

• 한국식품영양과학회지
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• 제31권5호
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• pp.770-774
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• 2002

레토르트 굴죽 개발을 위하여 원료의 조성 및 가공방법이 죽의 물성 및 기호도에 미치는 영향에 대하여 연구하였다. 쌀의 투입량은 10～12% 정도로 유지할 때 죽의 점도가 약 800 cp를 유지하여 적당했는데 쌀알의 안정성을 높이고 안정된 질감을 확보하기 위하여 사용한 쌀의 1/2을 마쇄하여 사용하는 것이 점도 향상 및 기호도에 유리하였다. 전분 원료 중 감자전분, 찰옥수수전분 및 Perfectamyl AC전분은 호화온도에 상관없이 거의 일정한 점도를 유지하여 작업시 온도 편차에 따른 품질 변화를 유발하지 않기 때문에 좋은 조건을 지니고 있어 레토펀트 죽의 제조에 좋은 조건을 지니고 있었으며 특히 찰옥수수전분은 살균 후 소비시에는 오히려 점도가 감소하여 일정한 점도를 유지하는 특징이 있어 레토르트 죽에 적합할 것으로 판단되었다. 변성 전분 중 Purity CSC전분은 냉-해동 후 조직 이 호화온도에 따라 묽은 풀과 같은 정도에서 순두부 정도로 나타났으며 호화 온도에 무관하게 수분분리가 적으므로 찰옥수수전분에 약 25% 정도를 혼합하여 사용할 때 좋은 물성을 유지할 수 있었다. 레토르트 굴죽의 원료 분산성을 개선하기 위하여 Kan-than gum을0.2%정도 사용하면 식감에 영향을 미치지 않고 품질 안정성을 유지할 수 있었다. 따라서 레토르트 굴죽의 최적 조성을 쌀 10%(이중 1/2은 마쇄), 찰옥수수전분 1.5%, Purity CSC 0.3%, xanthan gm, 0.2%, 식염 0.3%, 물 87.5%로 완성하였고 최적 조건 하에서 완성된 레토르트 굴죽을 상온에서 5개월 동안 저장한 후에도 안정된 물성이 확인되어 이들 원료의 가공적성이 레토르트 굴죽에 적합함을 확인하였다.

• 대한기계학회논문집B
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• 제35권6호
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• pp.585-592
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• 2011

냉시동 성능 개선은 연료전지 차량의 고분자 전해질 연료전지 발전 모듈 및 시스템의 내구성과 신뢰성 향상의 측면에서 매우 중요하다. 이에 본 연구에서는 영하의 기후에서 연료전지 차량의 초기 구동 시금속 분리판 표면에 형성된 바나듐 산화물 박막의 자기 발열 특성을 이용하여 신속한 온도 상승 구현이 가능한 냉시동 향상 기술을 제안하고, 실험적 방법을 통해 그 적용 가능성을 검증하였다. 졸-겔 침지 법에 의해 제조된 바나듐 산화물 박막의 특성 평가를 위해 X 선 회절, 광전자 분광, 전자 주사 현미경을 이용한 화합물 조성 및 미세구조 분석, 4-탐침법을 이용한 $-20{\sim}80^{\circ}C$의 온도 구간에서의 온도-저항 이력 특성 분석을 각각 수행하였다. 본 실험 결과, 냉시동 조건에서 박막의 자기 발열량은 연료전지 내부의 생성 수 결빙 방지에 필요한 열 에너지를 모두 충족시킬 수 있음을 확인하였다.

• 한국식품위생안전성학회지
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• 제12권3호
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• pp.240-253
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• 1997

The main problems contributing to food poisoning outbreaks in institutional settings and a home were reviewed and analyzed through the epidemiological investigations of food poisoning. The major documented factors included improper holding temperatures, inadequate cooking, poor personal hygiene, cross-contamination and contaminated equipment, food from unsafe sources, failure to follow food hygiene policies, and lack of education, training, monitoring and superivision. Usually more than one factor contributed to the development of an outbreak. (1) Use of improper holding temperatures was the single most important factor contributing to food poisoning. They included improper cooling, allowing a laps of time (12 hours or more) between preparing food and eating it, improper hot holding, and inadequate or improper thawing. Food thermometers were not used in most of the instances. (2) In inadequate cooking, the core temperature of food during and after cooking had not been measured, and routine monitoring was limited to recording the temperature of plated meals. Compared with conventional methods of cooking, microwave ovens did not protect against food poisoning as effectively. Centralized food preparation potentially increased the risk of food poisoning outbreaks. (3) Poor personal hygiene both at the individual level (improper handwashing and lack of proper hygienic practices) and at the institutional level (poor general sanitization) increased the risk of transmission. Person to person transmission of enteric pathogens through direct contact and via fomites has been noted in several instances. (4) Obtaining food from unsafe sources was a risk factor in outbreaks of food poisoning. Food risks were high when food was grown or harvested from contaminated areas. Possibilities included contamination in the field, in transport, at the retail site, or at the time it was prepared for serving. (5) Cross-contamination and inadequate cleaning/handling of equipment became potential vehicles of food poisoning. Failure to separate cooked food from raw food was also a risk factor. (6) Failure to follow food hygiene policies also provided opportunities for outbreaks of food poisoning. It included improper hygienic practices during food preparation, neglect of personnel policies (involvement of symptomatic workers in food preparation), poor results on routine inspections, and disregarding the results and recommendations of an inspection. (7) Lack of formal and in-service education, training, monitoring, and supervision of food handlers or supervisors were critical and perhaps neglected elements in occurrences of food poisoning.

• 한국수정란이식학회지
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• 제9권1호
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• pp.7-14
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• 1994

The present experiments on cryopreservation were designed to examine the effects of solution toxicity, equilibration time and cell stages on the post-thaw survival of bovine IVF embryos. The oocytes were matured in vitro(IVM) for 24 hrs. in TCM-199 supplemented with 35 $\mu$g /ml FSH, 10 $\mu$g /ml LH, 1 $\mu$g /ml estradiol-17$\beta$ and granulosa cells at 39$^{\circ}C$ under 5% $CO_2$ in air. They were fertilized in vitro(IVF) by epididymal spermatozoa treated with heparin for 24 hrs., and then the zygotes were co-cultured in vitro(IVC) with bovine oviductal epithelial cells for 7 to 9 days. The bovine IVF embryos were exposed to the EFS solution in one step at room temperature, kept in the EFS solution during different period for toxicity test, vitrified in liquid nitrogen, and thawed rapidly. 1. after the bovine blastocysts were exposed to EFS solution for 2 min. at room temperature and then they were washed in 0.5 M sucrose solution and TCM-199, they were cultured to examined cryoprotectant induced injury during exposure, Most of the embryos(95.0%) developed to reexpanded blastocoels. However, when the exposure time was extended to 5 and 10 min, these development rates dropped dramatically in 5 min. (69.5%) and 10 min. (47.4%), respectively, 2. When the bovine IVF embryos were vitrified in EFS solution after the equilibration for 1 and 2 min. exposure, The embryos to have reexpanded blastocoels following thawing, washing and culture processes were found to he 82.6 and 73.9%, respectively. However, when the exposure time was extended to 3 min, this survival rate dropped to 18.2%. The optimal time for equilibration of bovine IVF blastocysts in EFS solution seemed to he 1~2 min. 3. When the bovine IVF embryos were equilibrated for 1 min. the significantly (P<0. 05) higher post-thaw survival rates were obtained from the embryos of blastocyst stage(81.3%) than morulae stage(5. 1%). The optimal cell stage for viterification with EFS solution proven to he blastocyst stage in bovine IVF embryos. 4. The number of blastomeres of blastocyst stage was examined with nuclear staining with Hoechst 33342 during 7 to 9 days post-insemination. The cell counts of frozen bovine IVF embryos were found significantly(P$\geq$7.5 and those of the fresh embryos 76.6$\geq$7. 1, which were cultured in the sarne period and conditions as frozen embryos.