• Journal of Embryo Transfer
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• v.32 no.3
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• pp.235-241
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• 2017

To preserve genetic materials, cryopreservation of the semen from live animals is the main technique to establish cryo-banking system which could be used for artificial insemination and embryo transfer. However, the population of Korean black goat (KBG) becomes to dwindle in number and is now faced genetic erosion by crossbreeding with non-native breeds in small KBG farms. In this study, simple freezing method was used to preserve frozen semen from KBG using spermatozoa of cauda epididymis (CE) and electro-stimulated semen (ES). The negative effects of seminal plasma on fresh sperm was confirmed using precipitation test of Triladyl egg yolk diluent and sperm viability after thawing was compared between CE and ES spermatozoa. When seminal plasma of fresh ES semen was washed with semen washing media (SWM), the rates of live sperm shown no significant difference between CE and ES spermatozoa before freezing. However, the survival rate of frozen/thawed CE sperm was higher than ES ($74.6{\pm}10.6%$ vs $53.8{\pm}5.2%$) with significant difference (p < 0.05). The results of longevity test on frozen/thawed sperm from CE showed healthier sperm than ES. Therefore, spermatozoa from CE could be used for cryo-banking system in KBG lines. The more studies are needed to increase survival rate of ES semen.

• Resources Recycling
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• v.19 no.6
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• pp.36-42
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• 2010

Researches on resources recycling in the field of construction have made an extensive progress such as recycled aggregate of waste concrete and recycling of asphalt. On the other hand, there are almost never researches on pavement method with used waste frying oil. In South Korea, 0.2 million ton used waste frying oil is discharged every year. It is guessed that about 0.1 million ton used waste frying oil can be collected. If used waste frying oil is recycled, it is expected that disuse cost will be reduced and water pollution of rivers will be prevented. Therefore, the purpose of the study was to evaluate on mechanical features (strength, water resistance, chemical resistance, abrasion resistance, freezing and thawing resistance and permeable coefficient) whether dense graded permeable concrete mixing silica sand with flexible alkyd resin manufactured by making ester reaction with collected used waste frying oil to make alkyd resin could be applied to road pavement for non-roadway. The results of the study were as follows. In flexural strength, it had 1.6 times as much as road design standard 4.5MPa. In water resistance, chemistry resistance and freezing and thawing resistance, they had lack of strength in early age. As age went by, they didn't have large changes. And curing temperature had phenomenon of increase in strength at rather low temperature than high temperature by glass transition temperature of resin. Therefore, considering workability, strength and durability when it was applied to road pavement, it was reasonable that the mixing ratio of flexible alkyd resin was 10~15% in comparison with silica sand weight.

• The Korean Journal of Blood Transfusion
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• v.29 no.3
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• pp.291-300
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• 2018

Background: The use of a functionally closed system for the glycerolization and deglycerolization of red blood cells (RBCs) allows for prolonged post-thaw storage for more than 24 hours. The aim of this study was to assess glycerolization and deglycerolization processing for RBCs using a high glycerol method in the automated, closed system provided by Haemonetics ACP 215. Methods: Thirty-five packed RBCs were glycerolized using the ACP 215 to a final concentration of 40% (wt/vol). The units were either frozen as such (n=30) or excess glycerol was removed (n=5) before freezing. After storage at $-80^{\circ}C$, the units were thawed, deglycerolized and resuspended in SAG-M. The frozen-thawed RBCs were stored at $4^{\circ}C$, and analyzed for their stability and in vitro quality. Results: No prefreeze excess glycerol removal units showed significantly less potassium leakage during post-thaw storage compared to the prefreeze excess glycerol removal units. All measurements of the stability and in vitro quality of thawed RBCs prepared from frozen RBCs without the prefreeze removal of excess glycerol during post-thaw storage at $4^{\circ}C$ for 7 days were acceptable to the American Blood Bank Association's standards and European standards. Conclusion: RBCs frozen without prefreeze removal of excess glycerol and the ACP 215 simplifies cryopreservation procedure and increases the stability of frozen-thawed RBCs. This increases the practical applicability of cryopreserved RBCs in blood transfusion practice.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.69-74
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• 2023

As a chemical de-icing method, propylene glycol de-icing fluid is applicable for melting ice caused by snow and ice adhering to the lower part of high-speed rail rolling stock and bogie parts in winter. By spraying propylene-glycol de-icing fluid on high-speed rail rolling stock and bogie parts in advance to minimize snow adhesion, ice-melting efficiency can be further improved. In the case of high-speed rail rolling stock, even if propylene-glycol de-icing fluid is sprayed, the anti-icing performance is poor because the fluid is almost lost on the surface of the vehicle when operating at high speed. In this study, in order to prevent freezing caused by snow and ice adhering to the lower part of high-speed rail rolling stock and bogie parts, we have investigated the properties of propylene-glycol de/anti-icing fluid containing water-repellent agents that prevent surface freezing. We tried to find the optimal component for de/anti-icing fluid for high-speed rail rolling stock by evaluating the ice melting performance, contact angle, and anti-icing performance according to the types of water-repellent agent. As a result of the evaluation, it was confirmed that an de/anti-icing fluid containing an ethoxysilane-type water repellent agent was most suitable.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.555-566
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• 2023

In this study, a composite phase change material (CPCM) produced using the SOL-GEL technique was developed as a thermal energy storage medium for low-temperature applications. Tetradecane and activated carbon (AC) were used as the core and supporting materials, respectively. The tetradecane phase change material (PCM) was impregnated into the porous structure of AC using the vacuum impregnation method, and a thin layer of silica gel was coated on the prepared composite using the SOL-GEL process, where tetraethyl orthosilicate (TEOS) was used as the silica source. The thermal performance of the CPCM was analysed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC results showed that the pure tetradecane PCM had melting and freezing temperatures of 6.4℃ and 1.3℃ and corresponding enthalpies 226 J/g and 223.8 J/g, respectively. The CPCM exhibited enthalpy of 32.98 J/g and 27.7 J/g during the melting and freezing processes at 7.1℃ and 2.4℃, respectively. TGA test results revealed that the AC is thermally stable up to 500℃, which is much higher than the decomposition temperature of the pure tetradecane, which is around 120℃. Moreover, in the case of AC-PCM and CPCM thermal degradation started at 80℃ and 100℃, respectively. The chemical stability of the CPCM was studied using Fourier-transform infrared (FT-IR) spectroscopy, and the results confirmed that the developed composite is chemically stable. Finally, the surface morphology of the AC and CPCM was analysed using scanning electron microscopy (SEM), which confirmed the presence of a thin layer of silica gel on the AC surface after the SOL-GEL process.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.92-92
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• 2002

Considerable attention has been focused on the cryopreservation of semen and estrus induction in dog, as consequence of poor productivity caused by long anestrus period, in order to enhance the productivity of youngs and to preserve the breeds. The objectives of this study were to evaluate semen quality after cryopreservation and to evaluate the Pregnancy rate after insemination (AI). Fifty infertilie dogs (age 2∼3 years) were selected for the study and divided into three different estrus induction treatment groups. Group 1: dogs (n=15) were given clomifene (0.1 mg/kg) orally for five days at 12 hr intervals. Group 2: dogs (n=15) were given bromocriptine (50 $\mu\textrm{g}$/kg) orally for five days at 12 hr intervals, followed by single injection intravenously of 500 IU GnRH (Group 3, n=20) when pro-estrus occurred. The rates of pregnancy in estrus inducted dogs mated naturally compared to those inseminated artificially with ejaculated fresh semen and frozen-thawed semen. Estrus detection was performed using the method of vaginal smear and confirmed by the plasma progesterone assay. The ejaculated semen to freeze was exposed to a mixture of Tris extender with cryoprotectant (Trisma, 81 mM: TES, 209 mM: citric acid, 6 mM; glucose, 5 mM; glycerol, 8%) and cryopreserved gradually by slow-cooling at 17 cm above the surface of liquid nitrogen (LN$_2$) for 23 min. The motility of frozen-thawed spermatozoa was assessed by phase-contrast microscopy. To assess their viability and acrosome content, spermatozoa were stained with a vital stain and Fluorescence conjugated lectin Pisum Savitum Agglutinin (FITC/PAS), respectively. Pregnancy was confirmed by ultrasonograpy on day 25, 35 and 55 post insemination. The use of fresh semen, the pregnancy rates were observed 66.6, 66.6, 75.0 and 83.3% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. The use of frozen-thawed semen, the pregnancy rates were observed 66.6, 33.3, 50.0 and 60.0% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. No difference was observed in the number of offspring produced among natural estrus and treated groups inseminated with fresh or frozen-thawed semen. In conclusion, the pregnancy rate of dogs treated with a combination of GnRH and bromocriptine was more effective than use of clomifene or bromocriptine only. In addition, frozen-thawed semen can be used successfully far artificial insemination in dog.

• Korean Journal of Poultry Science
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• v.41 no.1
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• pp.21-27
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• 2014

To preserve chicken genetic materials like cryopreserved spermatozoa, various kinds of freezing agents like glycerol, dimethylsuloxide, dimethylformamide or dimethylacetamide have been used for rooster semen preparation. Recently, the usage of N-methylacetamide (MA) for Ogye rooster semen preservation resulted in hatched chicken successfully. In this study, we investigated the effects of 7, 9 and 11% of MA on the viability, fertility and hatchability of frozen-thawed rooster semen using artificial insemination. The results of viability, fertility and hatchability in frozen semen with 7%, 9% or 11% MA were $35.16{\pm}6.12%$, $67.83{\pm}15.3%$ and $66.2{\pm}16.3%$ of motile sperm rate, 21.5%, 34.7% and 25% of fertility rate, and 100%, 89.5% and 87.5% of hatchability rate. The results of control group with frozen semen were 96.0% of fertility rate and 92.2% of hatchability rate. With these results, the concentration range of MA as a freezing agent of rooster semen could be 7~9% of media. The higher concentration of 9 % MA could decrease the fertility rate of thawed semen not the rate of hatchability rate. So the use of MA without affecting fertility rate would be a key point of freezing method of rooster semen for poultry genetic resource preservation.

• Korean Journal of Poultry Science
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• v.39 no.4
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• pp.291-295
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• 2012

The use of methylacetamide (MA) as a cryoprotective agent for freezing Korean Native Black rooster Ogye semen was examined with artificial insemination. The diluted Ogye semen with HS-1 was subjected for 2 step dilution method of cryopreservation in which the final concentration of MA was adjusted to 7.5%. The sperm viability after thawing was reduced from $95.17{\pm}0.93%$ to $55.93{\pm}1.38%$ which was confirmed by live-death analysis based on Fluorescence-Activated Cell Sorting (FACS). The rates of fertilized eggs with fresh or frozen-thawed semen were reduced from $94.98{\pm}3.93%$ to $66.36{\pm}8.43%$ at day 7 with significant difference. However, the hatching rates of experiments at day 21 did not shown difference between $92.64{\pm}2.33%$ and $90.45{\pm}8.05%$ (P<0.05). With these results, the utilization of MA for freezing of Ogye spermatozoa could affect on viability of frozen-thawed semen but not on the fertility of lain eggs and hatchability of fertilized eggs and also provide possible tools of freezing for poultry genetic resource conservation.

• International Journal of Industrial Entomology and Biomaterials
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• v.40 no.1
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• pp.22-27
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• 2020

Silkworm powder was prepared from 3^rd day of 5^th instar silkworm through various drying technology including freeze drying, hot wind drying, infrared drying, and microwave drying. The shape of silkworm dried was different with the drying methods. Freeze drying and microwave drying silkworm looked its original form, but hot wind drying and infrared drying silkworm looked shriveled and crumpled. The color of silkworm powder freeze-dried changed from yellowish green to hazel with lowering freezing temperature. Heavy metals including Pb, Cd, As, and Hg were lower the food criteria. The results of 1-deoxynojirimycin analysis was shown that BaekOkJam and GoldenSilk silkworm powder was satisfied the criteria of functional food, but YeonNokJam silkworm powder was lower than the criteria. The amino acid composition of silkworm was similar regardless of the frozen temperature in freeze drying process.

• Applied Microscopy
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• v.39 no.2
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• pp.185-189
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• 2009

Studies about the structure of Drosophila melanogaster retinal cell using electron microscopy have been carried out in details since 1960s. However, these results can have limitations in functional research because of two-dimensional structure. In this study, the adult retina of Drosophila melanogaster was investigated by employing high pressure freezing method, serial sections, high voltage electron microscopy, and 3-dimensional reconstruction method. From there results, mitochondria, microtubules, and nuclei were reconstructed as 3-dimensional structure using IMOD program. The 3D structure of these organelles showed that mitochondira mainly located in distal region near lens, and microtubule mainly located in distal and basal region. The 3D reconstruction of these organelles can be used for a critical evaluation in the dynamic change of cellular organelles caused by functional abnormality like retinal degeneration.