• Clinical and Experimental Reproductive Medicine
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• v.20 no.1
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• pp.31-36
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• 1993

The effects of freezing and 1,2-propanediol on early and late pronucleate stage mouse ova were investigated in terms of survival after thawing and development in vitro. The samples were divided into two groups according to different age in pronucleate ova: ova in(1) early pronuclear stage with two distant pronuclei at 18h after hCG injection, and (2) late pronuclear stage with adjacent pronuclei at 30h. Zygotes in the late pronuclear stage have been proven to be more resistant to 1,2-propanediol, showing a significantly higher developmental rate than zygotes in early stage (80.3 versus 66.3%, <0.05), but survival rate was similar in the two groups (91.0 versus 93.5%). After freezing and thawing, survival and developmental rates were decreased in both groups when compared to the control group (54.3 versus 92.3%, 47.7 versus 73.3%. respectively). And developmental rate in the late pronuclear stage zygotes showed significantly higher than in early (55.4 versus 40.0%) after thawing. In conclusion, early pronucleate mouse ova have a lower developmental capacity in vitro and a lower survival rate after freezing and thawing than late ova. These findings suggest that the timing of freezing could be important for survival and further development in vitro in cryopreservation of human pronucleate ova.

• Food Science and Preservation
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• v.15 no.5
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• pp.675-681
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• 2008

This study investigatedthe quality of mashed red pepper after application of various freezing and thawing conditions. Two freezing temperatures ($-70^{\circ}C$, $-10^{\circ}C$), two thawing temperatures ($0^{\circ}C$, $40^{\circ}C$), and two thawing methods (water-thawing, air-thawing), were employed. Changes in levels of capsaicinoids, vitamin C, free sugars, organic acids, and capsanthin were measured. Capsaicinoids, vitamin C,and free sugar contents were lowest in pepper treated at $-10^{\circ}C/40^{\circ}C$ (freezing/thawing), and the loss rates were 38.0, 79.4 and 24.6%, respectively. When thawing methods were compared, chemical contents were higher in air-thawed samples than in water-thawed peppers, but there was a statistically significant difference only in vitamin C content. Free sugar content after $-70^{\circ}C$ freezing were higher than after $-10^{\circ}C$ freezing, irrespective of the thawing method used. Initial citric acid, malic acid, and succinic acid contents were 44.90, 30.76 and 20.65 mg/100 g, and there was no significant difference between peppers treated with different freezing and thawing conditions. It is recommended that the best method for preserving the overall quality of mashed red pepper is freezing at $-70^{\circ}C$ and thawing at $0^{\circ}C$ in air.

• Journal of Ocean Engineering and Technology
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• v.23 no.5
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• pp.54-60
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• 2009

Exposed to various environments, concrete confronts degradation by a lot of physical and chemical reaction. Though so many experiments and theorizations on the single condition of concrete degradation have been carried out by constant studies, the truth for now is that there are few studies on the compound phenomenon of degradation related with marine environments. Accordingly, this study measured the degree of degradation in the change of external shape, the change of unit weight and compressive strength, ultrasonic velocity test, and the change of length, etc. after exposing the specimen of cement mortar to the environment between 0 cycle and the maximum of 300 cycles under the condition of aquatic curing, freezing and thawing, and compound degradation, using mineral admixture effective for concrete degradation as a binder. The result indicated that the case of adding mineral admixture showed greater resistance than that of using OPC only, and specifically, the specimen with the additive of slag powder and three component system showed very excellent resistance to freezing and thawing, and compound degradation.

• Korean Journal of Animal Reproduction
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• v.10 no.2
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• pp.175-181
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• 1986

These experiments were carried out to clarify the effects various kinds of cryoprotectants which were frequently used in freezing embryos of domestic animals on the survival of frozen-thawed mouse embryos. As cryoprotectant, glycerol, DMSO and methanol were used and the procedures of adding them in medium were practiced by one-step or six-step adding method. Morphologically normal mouse embryos developed to blastocyst by in vitro culture after freezing and thawing were transferred to pseudopregnant recipients by surgical procedures. The results obtained in these experiments were summarized as follows: 1. The survival rates of the frozen-thawed 8-cell embryos, morulas and blastocysts following one-step addition of glycerol were 83.6, 80.3 adn 70.3%, respectively, while following six-step addition of glycerol, 69.2, 56.3 and 66.7% respectively. 2. When glycerol, DMSO and methanol were used as cryoprotectant under the same condition of freezing and thawing, the survival rates of frozen-thawed embryos were 74.0, 76.1 and 37.6%, respectively. 3. The implantation rate of embryos transferred to pseudopregnant recipients after freezing and thawing was 49.2%.

• Journal of Embryo Transfer
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• v.8 no.1
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• pp.1-7
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• 1993

This study was carried out to investigate the survival rates of late mouse molulae frozen in the state of vitrification and then thawed after equilibrating them separately in EFS 40, GFS 40 and DFS 40 at 1$0^{\circ}C$. The results obtained are as follows : 1. Freezing in the state of vitrification and thawing late mouse molulae after equilibrating them at l0$0^{\circ}C$ in EFS 40 for 30 seconds, one minute and two minutes, we obtained survival rates of 76.7%, 96.7% and 100%, respectively. 2. Freezing and thawing them after equilibrating at 1$0^{\circ}C$ in GFS 40 for 30 seconds, one minute and two minutes, we obtained survival rates of 60%, 96.7% and 10%, respectively. These results are as similar as in the case of EFS 40. 3. Freezing and thawing them after equilibrating at l$0^{\circ}C$ in DFS 40 for 30 seconds and one minute, we obtained survival rates of 62.1% and 0%, respectively. These results represent lower survival rates than those obtained with EFS 40 and GFS 40. In conclusion, even equilibrating late mouse molulae in EFS 40 and GFS 40 at 1$0^{\circ}C$ for more than one minute gives a survival rate of more than 97%, while equilibrating them in DFS 40 at 1$0^{\circ}C$ for more than one minute results in a 0% survival rate, which means that DFS 40 has a strong toxicity.

• Food Science of Animal Resources
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• v.33 no.6
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• pp.723-729
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• 2013

In this study, the quality characteristics due to the influence of various thawing methods on electro-magnetic and air blast frozen beef were examined. The loin and round of second grade Hanwoo were sliced into 5-7 cm thickness and packed with aerobic packaging. The packaged beef samples, which were frozen by air blast freezing at $-45^{\circ}C$ and electro-magnetic freezing at $-55^{\circ}C$, were thawed by 4 thawing methods with refrigeration ($4{\pm}1^{\circ}C$), room temperature (RT, $25^{\circ}C$), cold water ($15^{\circ}C$), and microwave (2450 MHz). These samples were thawed to the point, which were core temperature reached $0^{\circ}C$. Analyses were carried out to determine drip and cooking loss, water holding capacity (WHC), moisture contents and sensory evaluation. Frozen beef thawed by microwave indicated a lower drip loss (0.66-2.01%) than the other thawing methods (0.80-2.50%). Cooking loss after electro-magnetic freezing indicated 52.0% by microwave thawing for round compared with 41.8% by refrigeration, 50.1% by RT, and 50.8% by cold water. WHC thawing by microwave with electro-magnetic freezing didn't showed any difference depending on the thawing methods, while moisture contents was higher thawing by microwave with electro-magnetic freezing than refrigeration (71.9%), RT (75.0%), and cold water (74.9%) for round. The texture of sensory evaluation for round thawed by microwave result was the highest than refrigeration (4.7 point), RT (6.4 point) and cold water (6.6 point), while sensory evaluation was no significant difference. Therefore, it was shown that microwave thawing is an appropriate way to reduce the deterioration of meat quality due to freezing.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.803-807
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• 2011

Human umbilical Mesenchymal Stem Cell(uMSC) has been known as one of major component to regenerate connective tissues such as bone, cartilage, fat and others. The effect of low(5%), normotensive(20%) oxygen and freezing-thawing damage on proliferation of uMSC were investigated. low oxygen concentration culture of uMSC resulted in enhanced proliferation significantly($p$ <0.05) than 20% of oxygen culture. After the freezing-thawing injury to uMSC, 5% oxygen culture showed marked proliferation of uMSC than that of 20% oxygen($p$ <0.05) in the 5th passage of uMSC. Expression of antioxidant enzymes such as superoxide anion 1 and glutathione peroxidase 1 appeared marked in 20% oxygen cultured uMSC, which suggest oxidative stress could induce less proliferation of uMSC. Above findings would suggest proliferation of uMSC in 5% of oxygen will give more yields.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.6
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• pp.97-103
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• 2009

This study was performed to evaluate the strength and durability properties of recycled polymer concrete using unsaturated polyester resin and recycled aggregates. Unsaturated polyester resin, natural and recycled aggregates and fly ash were used. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes (5-10 and 5-25 mm) and unit binder contents (10% and 12%). Tests for the compressive and flexural strength, freezing and thawing and durability for 20% sulfuric solution were performed. The compressive and flexural strength of recycled polymer concrete were in the range of 85~97 MPa and 17.9~20.8 MPa, respectively. The strengths of recycled polymer concrete using recycled aggregate have similar or slightly decreased compared to polymer concrete using natural aggregate. After 300 cycles of freezing and thawing, weight decrease ratio and durability factor of recycled polymer concrete were in the range of 0.13~1.42% and 94~99, respectively.

• Journal of Embryo Transfer
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• v.10 no.3
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• pp.243-250
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• 1995

Frozen storage of the oocytes has been used in a few mammalian species including mouse, hamster, human and cattle. However, frozen4hawed oocvtes show different sperm penetration on the levels of the zona pellucida and the plasma memhrane when compared with fresh oocytes. To elucidate biological changes occurring during freezing and thawing, we examined the kinetics of sperm penetration into frozen-thawed hamster oocytes. Oocytes obtained from superovulated female golden hamsters were frozen-thawed in an autofreezer according to an established method. Fresh and frozen4hawed oocytes were fertilized in vitro with capacitated hamster spermatozoa after removing the zona pellucida. The oocytes were examined at 1, 2, 3 and 6 h postinsemination. Sperm penetration found to be 1 h delayed in frozen-thawed oocytes. Other parameters such as degree of polyspermy and decondensing sperm heads were not affected by freezing and thawing. The results suggest that freezing and thawing may cause changes in the egg membrane surface and subsequently which leads to delay in the sperm-egg fusion.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.221-224
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• 2004

Several factors of concrete durability decline factor are acted as complex deterioration and is happened not that happen by simplicity deterioration. Specially, in case of sea construction, as complex salt damage, carbonation and freezing & thawing, concrete surface and pore structure is deteriorated. Therefore, analyzing concrete carbonation and pore structure after freezing and thawing test by fresh water and sea water in this research, we wish to study about acceleration of decline of durability and complex deterioration by concrete surface deterioration in sea environment.