• 한국가축번식학회지
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• 제21권1호
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• pp.25-30
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• 1997

This study was done to find out the preservation possibility of liquid boar semen at variabel room temperature of 9 to 16$^{\circ}C$. The percentages of sperm motility and NAR acrosome were highest in B tschwiler extender compared to B tschwiler＋Hepes, Andro＋Hepes and Andro extenders. The extenders with Hepes buffer showed detrimental effect for preservation of liquid boar semen. The pH of ejaculated sperm-rich fraction was 7.5. The pH of B tschwiler＋Hepes, B tschwiler, Andro＋Hepes and Andro extenders was 6.9, 7.5, 7.1 and 8.1, respectively. The pH of liquid boar semen with B tschwiler＋Hepes, B tschwiler, Andro＋Hepes and Andro extenders was 6.6, 6.9, 6.7 and 6.9 at 1st day of storage, and 5.5, 5.7, 5.6 and 5.8 at 7th day of storage, respectively. Gilts and sows were inseminated twice with liquid boar semen stored at 9~16$^{\circ}C$ in B tschwiler extender for 3~4 days. Farrowing rate, litter size and average pig weight at birth between AI and natural service did not differ significantly in gilt and sow, respectively. However, sow showed higher farrowing rate and litter size compared to gilt both in AI and in natural service. As a result of this study, we found out that liquid boar semen can be stored for 5~7 days at uncontrolled room temperature of 9~16$^{\circ}C$ in B tschwiler extender.

• 한국임상수의학회지
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• 제36권5호
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• pp.259-265
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• 2019

This study was designed to investigate the effects of alpha-glucosyl rutin (G-rutin) and its comparative effects with other antioxidants (glutathione: GSH, catalase: CATA and beta-mercaptoethanol : ${\beta}ME$) on dog sperm freezing. In the first experiment (E1), the spermatozoa were diluted in freezing extender supplemented with 0 (control), 0.001, 0.01, or 0.1% G-rutin and frozen using liquid nitrogen ($LN_2$). The progressive motility, reactive oxygen species (ROS) level and apoptosis of spermatozoa were assessed after sperm thawing at $37^{\circ}C$ for 25 sec. In the second experiment (E2), 0.1% G-rutin group was compared with 10 mM ${\beta}-ME$, $5{\mu}M$ GSH and $50{\mu}M$ CATA groups by assaying progressive motility, viability and gene expression of Bcl-2 and SMCP after sperm freezing and thawing. In E1, 0.1% G-rutin group showed higher (P < 0.05) post-thaw progressive motility and lower (P < 0.05) ROS levels. In E2, the expressions of SMCP in G-rutin group were higher (P < 0.05) than in CATA group while Bcl-2 expression of G-rutin group was higher (P < 0.05) than ${\beta}-ME$ and CATA groups. However, there were no significant differences in progressive motility and viability. Therefore, we suggest that G-rutin can be used as a potentially antioxidative supplement in dog sperm freezing extender on the basis of gene expression related to motility and apoptosis as well as ROS level.

• 터널과지하공간
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• 제32권4호
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• pp.243-253
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• 2022

본 연구에서는 회전식 절삭시험기를 활용하여 TBE (Tunnel Boring Extender)의 굴착효율을 평가하였다. 회전식절삭시험에서 TBE에 의한 굴착과정을 모사하기 위하여 중앙부가 선행 굴착되어 있는 중공형의 암석모사시험체를 모르타르를 이용하여 제작하였다. 회전식 절삭시험기에 설치된 언더커팅 디스크(undercutting disc cutter, UDC)를 이용하여 나선궤적을 따라 암석을 절삭함으로써 TBE에 의한 굴착과정을 모사하였으며, 언더커팅 디스크의 절삭조건을 변화시켜가며 절삭조건들이 커터작용력 및 비에너지에 미치는 영향을 살펴보았다. 시험결과로부터 UDC의 커터작용력은 반경압입깊이와 수직압입깊이가 증가함에 따라 선형적으로 증가하는 경향을 확인할 수 있었으며, 세 방향의 작용력 중 수직력의 비중이 매우 크게 나타났다. 반면 비에너지는 반경방향과 수직방향 압입깊이에 따라 지속적으로 감소하는 경향을 나타내었고, 특히 두 압입깊이의 비에 따라 비에너지가 최소화되는 지점이 나타날 것으로 판단되었다.

• Animal Bioscience
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• 제35권9호
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• pp.1351-1359
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• 2022

Objective: The objective of this study was to analyse the differentially abundant proteins caused by freeze-thawing of ram sperm and explore candidate proteins of interest for their ability to improve ram sperm cryopreservation outcomes in vitro. Methods: Sperm were from three mature Dorper. Fresh and frozen sperm proteins were extracted, and the differentially abundant proteins were analysed by mass spectrometry. Among these proteins, lactoferrin (LTF) was selected to be added before cryopreservation. Next, sperm samples were diluted in Tris extender, with the addition of 0, 10, 100, 500, and 1,000 ㎍/mL of LTF. After thawing, sperm quality was evaluated by motility, plasma membrane integrity, mitochondrial activity and reactive oxygen species (ROS). Results: Cryopreservation significantly altered the abundance of 40 proteins; the abundance of 16 proteins was increased, while that of 24 proteins was decreased. Next, LTF was added to Tris extender applied to ram sperm. The results showed that sperm motility and plasma membrane integrity were significantly improved (p<0.05) by supplementation with 10 ㎍/mL LTF compared to those in the control group. There was no significant difference in mitochondrial activity between the 0 ㎍/mL group and other groups (p>0.05). Supplementation of the cryoprotective extender with 10 ㎍/mL LTF led to decreased ROS levels compared with those in the control and other groups (p<0.05). Conclusion: The LTF is an important protein during cryopreservation, and the addition of 10 ㎍/mL LTF to a cryoprotective extender can significantly improve the function of frozen ram sperm.

• Elastomers and Composites
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• 제52권4호
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• pp.295-302
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• 2017

Polyurethane dispersion (PUD) polymers were synthesized by using polyether and polyester polyol. The effect of ionomeric centers, r(NCO / OH) values, chain extender process, and chain extender types on the adhesion properties was investigated. In the case of polyether-based PUD, the ionic center, r value, chain extension process and chain extender types were not adjusted even after adjustment. In the case of polyester-based PUD, when the ionic center content was more than 2.5%, the state of adhesive strength was $2.0kgf/cm^2$ or more. On the other hand, the initial adhesive strength was excellent at about $1kgf/cm^2$ when the ionic center content was over 3.5%. When the r value was 1.3 or more, it was found that the initial bonding strength and the state of bonding strength were excellent at about $1kgf/cm^2$ and $2.1kgf/cm^2$ or higher, respectively. An IR spectrum analysis of the synthesized PUD confirmed that PUD was composed of urethane based on the N-H characteristic peak at $3340cm^{-1}$ and the urethane characteristic peak at $1730cm^{-1}$. Moreover, the characteristic peaks of the isocyanate ($2260cm^{-1}$) used in the preparation of the prepolymer were not observed. As a result, the residual -NCO was not observed, and urethane was completely synthesized.

• 한국산학기술학회논문지
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• 제14권5호
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• pp.2075-2080
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• 2013

본 논문에서는 RE엔진에 적용하기 위한 냉각수 코어를 CFD 기술을 활용하여 개발하였다. 개선 모델은 배기밸브 주위와 사이의 온도를 저감하기 위한 냉각수 우회부를 추가하였다. 2번 실린더 블록 주위와 배기밸브 사이의 유량이 증가하였기 때문에, 베이스 모델대비 개선 모델의 유량 정체가 개선되었다. 결과적으로, 배기밸브 주위에서의 열전달이 향상되고, 전 유량 구간에서 기존 모델 대비 약 5%의 압력 강하량 저감 효과를 보이는 개선 모델을 얻을 수 있었다. 압력 강하량의 저감은 상응하는 냉각수 펌프의 부하를 저감하고 연비에 긍정적 영향을 미칠 것으로 판단된다.

• 한국임상수의학회지
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• 제18권4호
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• pp.345-349
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• 2001

The aim of this study was to investigate the effect of sperm preservation according to the various kinds of commercially available semen extenders and to investigate the effect of sperm preservation according to the various temperature storages of fresh-extended porcine semen. To investigate the effect of sperm preservation according to the various kinds of commercially available semen extenders, porcine semens diluted in 3 semen extenders, Beltsville Thawing Solution(BTS), Androhep and Kiev, were cooled at $8^{\circ}C$ storage temperature with a controlled cooling rate of $2-4^{\circ}C$/h. Motility, progressive motility, normal sperm(%) and sperm morphology were assessed comparatively. In motility and progressive motility, Androhep extenders revealed better result than other extenders. In normal sperm(%) and sperm morphology, 3 semen extenders revealed similar results. To investigate the effect of sperm preservation according to the various temperature storages of fresh-extended porcine semen, porcine semens diluted in BTS extender, were cooled at 3 storage temperatures($8^{\circ}C$, $12^{\circ}C$ and $17^{\circ}C$) with a controlled cooling rate of $2-4^{\circ}C$/h. Motility, progressive motility, normal sperm(%) and sperm morphology were assessed comparatively. In motility and progressive motility, $8^{\circ}C$ treatment group revealed better result than $12^{\circ}C$ and $17^{\circ}C$ treatment groups. In normal sperm(%) and sperm morphology, 3 temperatures of treatment groups revealed similar results.

• 한국산학기술학회논문지
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• 제14권6호
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• pp.2575-2580
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• 2013

본 논문에서는 RE엔진에 적용하기위한 흡기포트를 CFD 기술을 활용하여 개발하였다. 3차원 모델링을 진행하고 전산유체해석을 진행하였으며, 계산된 유량계수와 스월계수를 실험결과와 비교 분석하였다. 흡기포트의 convex 및 concave부 곡률을 최적화하여 Recirculation의 발생과 유동저항을 저감하였다. 결과적으로, 계산된 평균 유량계수는 0.383이고, 평균 스월수는 1.544로 일반적인 2밸브 엔진 시스템의 평균성능에 상회하는 우수한 성능을 나타내었다.

• 대한수의학회지
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• 제33권2호
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• pp.345-350
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• 1993

Multiple ejaculates were collected from four male mongrel dogs. The second fraction and the small volume of third fraction from the ejaculates were divided and treated as follows : control; addition of the egg-yolk Tris extender to the semen at $37^{\circ}C$. group I; Removal of seminal plasma, group II; addition of the glycerolated extender at $4^{\circ}C$, group III Removal of seminal plasma and addition of glycerolated extender at $4^{\circ}C$. The semen cooled to $4^{\circ}C$ was equlibrated for 2hrs and preserved in refrigerator at $4^{\circ}C$. The preserved semen was evaluated for kinetics, morphology, motility and thermoresistance daily for 3 days. 1. The kinectics after preserved days 2 and 3 of group I was significantly higher than that of control(p<0.05). 2. There were no significant difference in abnormal morphology of each group between the periods of storage. 3. The motility after preserved day 1 and days 3 of group I was significantly higher than that of others(p<0.05), and the molity after preserved days 2 of group I and III was signficantly higher than that of others(p<0.05). 4. When the molity of preserved semen was measured during incubation at $37^{\circ}C$, the motility of four groups was declined at similar rates. There was no effect of removal of seminal plasma and glycerol addition on thermoresistance.

• 한국수정란이식학회지
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• 제32권1호
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• pp.9-15
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• 2017

The present study was aimed to determine the effect of green tea extract (GTE) and beta-mercaptoethanol (${\beta}$-ME) supplementation in boar sperm freezing extender on sperm motility, viability and reactive oxygen species (ROS) level. Experimental groups were allocated into Lactose-egg yolk (LEY) without antioxidant (control), GTE (1,000 mg/L GTE in LEY) and ${\beta}$-ME ($50{\mu}M$ ${\beta}$-ME in LEY). Spermatozoa extended with LEY were cooled to $5^{\circ}C$ for 3 h and then kept at $5^{\circ}C$ for 30 min following dilution with LEY containing 9% glycerol and 1.5% Equex STM (final sperm concentration: $1{\times}10^8/mL$). Spermatozoa were loaded into straws and frozen in nitrogen vapor for 20 min. Following thawing at $37^{\circ}C$ for 25 sec, sperm viability and ROS level were measured using fluorescent double stain Fertility(R) and cytometry, respectively. Motility and viability of GTE supplemented-group were higher than those of control and ${\beta}$-ME without significance. ROS level in GTE group showed significantly lower than control (P < 0.05). In conclusion, GTE supplementation in boar sperm freezing extender can reduce ROS generation during freezing.