• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2006.05a
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• pp.317-324
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• 2006

This study aims to find out cooling characteristics of TMA(Tri-Methyl-Amine, ($CH_{3})_{3}N$) 25wt%-clathrate compound with ethanol($CH_{3}CH_{2}OH$) such as supercooling, phase change temperature and specific heat. For this purpose, ethanol is added as per weight concentration and cooling experiment is performed at $-6{\sim}-8^{\circ}C$, cooling heat source temperature, and it leads the following result. (1) Phase change temperature is decreased due to freezing point depression phenomenon. Especially, it is minimized as $3.8^{\circ}C$ according to cooling source temperature in case that 0.5w% of ethanol is added. (2) If 0.5wt% of ethanol is added, average supercooling degree is $0.9^{\circ}C $ and minimum supercooling is $0.8,\;0.7^{\circ}C$ according to cooling heat source temperature. The restraint effect of supercooling is shown. (3) Specific heat shows tendency to decrease if ethanol is added. It is $3.013{\sim}3.048\;kJ/kgK$ according to cooling heat source temperature if 0.5wt% of ethanol is added. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA 25wt%-water clathrate compound by adding additive, ethanol. This can lead to shorten refrigerator operation time of low temperature thermal storage system and improve COP of refrigerator and efficiency of overall system. Therefore energy can be saved and efficiency can be improved much more.

• Journal of Embryo Transfer
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• v.28 no.3
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• pp.163-168
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• 2013

Embryo transfer (ET) technology is of high importance in modern cattle breeding programs. ET is one step in the process of removing one or more embryos from the reproductive tract of an outstanding donor female and transferring them to one or more recipient females. Embryos also can be produced in the laboratory via techniques such as in vitro fertilization (IVF). But the actual transfer of an embryo is only one step in a series of processes that may include some or all of the following: superovulation and insemination of donors, collection of embryos, isolation, evaluation and short-term storage of embryos, micromanipulation and genetic testing of embryos, freezing of embryos and embryo transfer. Cryopreservation and direct transfer of frozen-thawed embryos is common-place with pregnancy rates near that of fresh embryos. Polymerase chain reaction (PCR) technology is currently being used for sexing embryos, and this technology will be used for "embryo diagnostics" and "embryo genomics" in the future. Although, many limitations and problems remain to overcome, these and other new technologies promise to change livestock breeding drastically in the next decade.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.12
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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.

• Korean journal of food and cookery science
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• v.25 no.1
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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.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.92-96
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• 2003

Effects of vitamin C on the properties of bread including number of yeast cells, volume of bread, specific loaf volume, and hardness and sensory characteristics were evaluated. Vitamin C was added at various amounts to frozen doughs made through sponge &dough method using sweet dough formula and quickly frozen at $-40^{\circ}C$. Doughs were stored for 4 weeks at $-20^{\circ}C$. Evaluations were done after frozen dough was thawed, fermented, and baked every week. The bread with 150 ppm vitamin C revealed higher yeast cell survival rate during freezing storage, and higher specific and bread volumes than other doughs. Hardness of bread increased with increasing amount of vitamin C added. Bread with 100 ppm vitamin C revealed the highest sensory score. Consequently, addition of 100 ppm vitamin C to bread dough resulted in the highest overall evaluation.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.225-230
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• 1988

Emulsion stability, viscosity, and oil particle size of mayonnaise, prepared at various egg yolk contents, were investigated. With increasing of the egg yolk ratio, emulsion stability became stronger, viscosity became higher, and oil particle size became smaller. Freezing stability of mayonnaise containing below 6.5% egg yolk was reduced significantly. Referring to vibration separation, it was observed that stability of mayonnaise containing 2% and 3.5% egg yolk was very low and containing over 5% egg yolk was stable relatively. Viscosity of mayonnaise, stored at $-10^{\circ}C$, was reduced significantly during first 24hrs. and then levelled off. Oil particle size of mayonnaise, stored at $-10^{\circ}C$, became larger with increasing the storage time and the tendency to change was apparent in the sample containing below 6.5% egg yolk.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.18 no.1
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• pp.51-55
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• 2007

Objectives: The aim of this study is to compare the efficacy of fresh versus frozen reconstituted botulinum toxin type A (BTX-A) for the treatment of adductor type spasmodic dysphonia. Materials and Methods: After reconstitution with normal saline, BTX-A was used within 4 hours or it was kept frozen in a consumer grade freezer at about $-25^{\circ}C$ for up to 4 months. Thirty patients with spasmodic dysphonia were randomly assigned and treated with the either fresh or frozen BTX-A. About 83% of injections resulted in a satisfactory outcome with 5.3 months of mean action duration. Treatment outcomes and side effects of total 161 injections were compared along the duration of keeping BTX-A frozen. Results: There were no statistical differences in the duration of action, self-rated satisfaction score, and the duration of hoarseness and/or aspiration between fresh and frozen BTX-A treated groups. No significant side effects were observed and the frozen BTX-A were proved to be free of bacterial contamination. Conclusion: After being reconstituted and kept frozen, BTX-A may be safely used for more than 4 months without significant loss of its effectiveness or additional side effects.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.43-47
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• 2011

Korea has seasonal weathers which result in the frosting of soil in winter times, and the thawing of soil in spring. These climate characteristics result in the damaging of pavements, due to the repeated freezing and thawing of road pavements during winter and spring. In order to reduce these pavement damages, anti-frost heave layers are being specially installed, however it is being applied based on foreign researches, and therefore result in the waste of national budget. With this study, a database system was constructed for effective management and monitoring of measured temperatures and function data of 2 meters below the embankment, cut slope, and the cutting-embankment boundary, which are 15 regions picked by the frost index diagram. As the study result, an effective storage and management-purpose database was established for easy data searching and downloading for the pavement design engineers.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.299-306
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• 2021

Vitrification methods are commonly used for mammalian reproduction through the long-term storage of blastocyst produced in vitro. However, the survival and quality of embryos following vitrification are significantly low compared with blastocyst from in vitro production (IVP). This study evaluates that the survival of frozen-thawed bovine embryos was relevant to mitochondrial superoxide derived mitochondrial activity. Here we present supplementation of the cryopreservation medium with Mito-TEMPO (0.1 µM) induced a significant (p < 0.001; non-treated group: 56.8 ± 8.7%, reexpanded at 24 h vs Mito-TEMPO treated group: 77.5 ± 8.9%, re-expanded at 24 h) improvement in survival rate of cryopreserved-thawed bovine blastocyst. To confirm the quality of vitrified blastocyst after thawing, DNA fragmentation of survived embryos was examined by TUNEL assay. As a result, TUNEL positive cells rates of frozen-thawed embryos were lower in the Mito-TEMPO treated group (4.2 ± 1.4%) than the non-treated group (7.1 ± 3.5%). In addition, we investigated the intracellular ROS and mitochondrial specific superoxide production using DCF-DA and Mito-SOX staining in survived bovine embryos following vitrification depending on Mito-TEMPO treatment. As expected, intracellular ROS levels and superoxide production of vitrified blastocysts after cryopreservation were significantly reduced (p < 0.05) according to Mito-TEMPO supplement in freezing medium. Also, mitochondrial activity measured by MitoTracker Orange staining increased in the frozen-thawed embryos with Mito-TEMPO compared with non-treated group. These results indicate that the treatment of Mito-TEMPO during cryopreservation might induce reduction in DNA fragmentation and apoptosis-related ROS production, consequently increasing mitochondrial activation for developmental capacity of frozen-thawed embryos.

• Journal of the Korean Geotechnical Society
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• v.37 no.12
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• pp.107-116
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• 2021

In this study, a set of laboratory liquefaction test has been conducted using undisturbed samples collected from Songlim-park, Pohang where liquefaction phenomenon had been observed in 2017. Soil samples were frozen right after tube sampling to minimize the disturbances during transport, storage, and test preparation. Cyclic triaxial test has been carried out to evaluate the liquefaction resistance ratio of undisturbed soil samples. As a result, the liquefaction resistance ratio of samples collected from 8.0~8.8 m and 11.0~11.8 m were almost similar, and these values were approximately 0.04~0.07 larger than values estimated by simplified assessment method using field test results. It is expected that the application of undisturbed sample for the evaluation of liquefaction resistance could contribute to the economical design of geotechnical structures.