• Journal of Adhesion and Interface
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• v.19 no.3
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• pp.118-122
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• 2018

In this study, polyurethane hot melt adhesive containing ester groups was synthesized. Three kinds of chain extenders were used to find out the best chain extender. Results showed that adhesive containing 1,4-butanediol as a chain extender exhibited the highest peel strength among them. Also, it was found that there existed the optimum molecular weight of 1,4-butanediol containing adhesive for make the highest peel strength.. Moreover, hot melt adhesive containing 1,4-butanediol chain extender was applied to various kinds of textiles substrate such as cotton, polyester, and urethane coated polyester textiles to study the effects of different substrates on the peel strength and water resistance at $60^{\circ}C$. It was found that cotton substrate showed the highest peel strength and urethane coated polyester substrate showed the highest resistance on $60^{\circ}C$ water.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.195-204
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• 2019

In this study, we examined the effect of a liposome-based extender (Optixcell) and a tris-citric egg-yolk extender (Triladyl) on the frozen-thawed spermatozoa characteristics and the calving rate. The percentages for the total motility of the frozen-thawed spermatozoa were similar in the Optixcell and Triladyl groups. However, among the motile spermatozoa with a straight line velocity (VSL) ${\geq}25{\mu}m/sec$, the curvilinear velocity (VCL, ${\mu}m/sec$), VSL (${\mu}m/sec$), average path velocity (VAP, ${\mu}m/sec$), amplitude of lateral head displacement (ALH, ${\mu}m$), beat cross frequency (BCF, Hz), and plasma membrane integrity of the frozen-thawed spermatozoa for the Optixcell group were significantly higher than those for the Triladyl group. Furthermore, the calving rate in the Optixcell group (79.0%) was higher than that of the Triladyl group (62.8%). However, the acrosomal membrane integrity of the frozen-thawed spermatozoa in the Optixcell and Triladyl groups was not significantly different. These results indicate that semen freezing with Optixcell improved the motility and plasma membrane integrity of frozen-thawed spermatozoa and the calving rate of Hanwoo cows (native Korean cattle). In conclusion, our results suggest that semen freezing with the liposome-based extender Optixcell is more efficient than with the tris-citric egg-yolk extender Triladyl for improved offspring production.

• Journal of Environmental Science International
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• v.30 no.12
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• pp.1041-1051
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• 2021

The purpose of this study was to identify for extenders, adhesives, colorants, and fungicides suitable for the production of high-quality film-coated seeds of Chinese cabbage. In addition, the effect of various additives used for film coating on the germination of coated seeds and seedling vigor was investigated to establish appropriate treatment conditions for film coating efficiency. The germination rate and germination speed in Chinese cabbage film-coated seeds did not differ significantly depending on the type and concentration of the extender, while the use of Talc resulted in superior granulation capacity and adhesion of the seed coat in comparison to Zeolite. There was no significant difference in the germination rate depending on the type of adhesive used for film coating of Chinese cabbage seeds, but the germination rate was slightly slower in the film-coated seeds using carboxymethyl cellulose as an adhesive. On the other hand, the seeds coated with a film using 1% PVA as an adhesive not only maintained hardness enough to withstand external pressure, but also showed a high germination rate. In addition, the suitable disinfectant for film coating was venoram, and the treatment concentration was good at 250 mg·L^-1. The type of colorant used in the film-coated seeds of Chinese cabbage did not significantly affect the germination rate, germination speed, and seedling vigor. The seeds film-coated using the liquid colorant were superior in appearance to the seeds film-coated with the solid colorant, which implies the possibility of reduction in the manufacturing costs by using the water-soluble paints as colorants for film-coated seeds.

• Journal of Industrial Convergence
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• v.20 no.1
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• pp.63-68
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• 2022

In schools and corporate buildings, public WiFi Access Points are installed on the ceilings of hallways. In the case of an architectural structure in which a WiFi signal enters through a steel door made of a material with high signal attenuation, Internet connection is frequently cut off or fails when the door is closed. To solve this problem, our research implements an economical and portable WiFi extender using a Raspberry Pi and an auxiliary battery. Commercially available WiFi extenders have limitations in the location where the power plug is located, and WiFi extension using the WiFi hotspot function of an Android smartphone is possible only in some high-end models. However, because the proposed device can be installed at the position where the Wi-Fi reception signal is the best inside the door, the WiFi range can be extended while minimizing the possibility of damage to the original signal. Experimental results show that it is possible to eliminate the shadows of radio waves and to provide Internet services in the office when the door is closed, to the extent that web browsing and real-time video streaming for 720p are possible.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.349-354
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• 2022

This research was conducted in order to improve the hydrolysis resistance and mechanical properties of a resin compound and biodegradable mulching film, produced through the use of PBAT(Poly Butylene Adipate-co-Terephthalate) and PLA(Poly Lactic Acid). Various ratios of chain extenders and mechanical properties according to the annealing temperature conditions were investigated. The annealing process showed that compound resin can improve the crystallization capacity. In addition, incorporation of the chain extender was shown to improve and increase the tensile strength and hydrolysis resistance of the film. In the case of 0.6phr chain extender, the tensile strength was 383.0Kgf/cm², which was improved by 155% compared to the control films. When the blow up ratio(BUR) was 2.5, the optimal tensile strength of the film increased greatly, expanding up to 379.0/195.2kgf/cm² in the both machine direction (MD) and transverse direction (TD).

• Korean Journal of Animal Reproduction
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• v.22 no.4
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• pp.405-410
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• 1998

Boar semen extender Kp (Hankook Life-Science, Korea) was newly formulated by authors. This study was carried out to investigate the optimal concentrations of EDTA, Tris and citrate buffers in the Kp extender (Basic Kp) on the pH change during storage. And then the motility of boar sperm with the Kp pH stabilized (Modified Kp) was compared with those of commercial products imported into Korea such as BTS (Mini-tube. Germany; BTSg), BTS (Tri-bio, USA; BTSa) and Modena (SGI, USA). The pH values of all extenders were increased gradually with the storage days. Especially, the initial pH of Basic Kp was higher than that of BTSg, BTSa and Modena, and also higher than physiological pH of boar sperm (6.8∼7.5). When Basic Kp was added with various concentrations of EDTA (0, 0.63, 1.25 ＆ 2.37g/L), Tris (0, 0.18, 0.35, 0.71 ＆ 1.42g/L) and Citrate (0, 0.75, 0.81, 1.00, 1.25 ＆ 1.50g/L) buffers for pH down-regulation and stabilization of pH, the group added with 1.25g EDTA, 1.42g Tris and 1.00g Citrate well maintained the neutral range of pH during storage (6.88 at day1 to 7.33 at day6 in Modified Kp), Especially, the concentrations of the buffers added in Modified Kp were lower, until 1/2∼1/4 ranges, than those in Modena and other extenders. The motility of frozen-thawed boar sperm diluted with Modified Kp was significantly higher than that of Basic Kp, BTSg, BTSa and Modena (87.0% vs. 55.0∼71.0% at day1; 13.3% vs. 0∼6.3% at day6), Conclusively, Modified Kp in this experiment was kept the favorable physiological conditions in spite of low concentrations of the buffers and motility of frozen-thawed boar sperm was obtained better than that of Basic Kp and other commercial products such as BTSg, BTSa and Modena.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.199-205
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• 2020

Cryopreservation of semen is useful for animal breeding via artificial insemination (AI). However, the use of frozen-thawed boar semen is limited due to cryodamage. The aim of this study was to investigate the effects of different concentrations of MitoTEMPO (a mitochondria-targeted antioxidant) in lactose-egg yolk (LEY) extenders on kinetic characteristics of frozen-thawed boar sperms. Semen samples were collected from mature Duroc boars (2~3 years old) and cryopreserved in LEY extenders containing 0, 0.5, 5, 50, and 500 μM MitoTEMPO. The kinetic characteristics of frozen-thawed sperms were determined 0 and 30 min after thawing using computer-assisted sperm analysis (CASA). Results indicated that sperm motility immediately after thawing was significantly higher with 5 and 50 μM (50.46±2.71% and 46.96±2.66%, respectively) than with 500 μM MitoTEMPO (35.40±2.95%) (P<0.05). However, there were no significant differences in other kinetic characteristics except motility. In conclusion, the addition of MitoTEMPO to the sperm freezing extender may have a beneficial effect on motility of post-thawed boar semen.

• Journal of Embryo Transfer
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• v.27 no.2
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• pp.107-111
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• 2012

Miniature pig sperm cryopreservation is continually researched in biotechnology for breed conservation and reproduction. It is important to control the temperature at each stage of cryopreservation and cryoprotectant. It is also necessary to find the optimal cryoprotectant concentration and chemical elements of the extender. Recently, many studies have used various cryoprotectant materials, such as dimethyl sulphoxide (DMSO), ethylene glycol (EG), antifreeze protein (AFP), amides, and glycerol. Glycerol is a commonly used cryoprotectant. However, glycerol has critical cytotoxic properties, including osmotic pressure and it can cause irreversible damage to live cells. Therefore, We focused on membrane fluidity modifications can reduce cell damage from freezing and thawing procedures and evaluated on the positive effects of trehalose to the viability, chromatin integrity, and motility of boar sperm. Miniature pig sperm was separated from semen by washing with modified- Modena B (mMB) extender. After centrifugation, the pellet was diluted with the prepared first extender. This experiment was designed to compare the effects that sperm cryopreservation using two different extenders has on sperm chromatin. The control group used the glycerol only and it was compared with the glycerol and glycerol plus trehalose extender. Sperm viability and motility were evaluated using WST1 assays and computer-assisted semen assays (CASA). Chromatin structure was examined using acridine orange staining. For the motility descriptors, trehalose caused a significant (p<0.01) increase in total motility ($57.80{\pm}4.60%$ in glycerol vs. $75.50{\pm}6.14%$ in glycerol + trehalose) and progressive ($51.20{\pm}5.45%$ in glycerol vs. $70.74{\pm}8.06%$ in glycerol + trehalose). A significant (p<0.05) increase in VAP ($42.70{\pm}5.73{\mu}m/s$ vs. $59.65{\pm}9.47{\mu}m/s$), VSL ($23.06{\pm}3.27{\mu}m/s$ vs. $34.60{\pm}6.58{\mu}m/s$), VCL ($75.36{\pm}11.36{\mu}m/s$ vs. $99.55{\pm}12.91{\mu}m/s$), STR ($54.4{\pm}2.19%$ vs. $58.0{\pm}1.63%$), and LIN ($32.2{\pm}2.05%$ vs. $36.0{\pm}2.45%$) were also detected, respectively. The sperm DNA fragmentation index was 48.8% to glycerol only and 30.6% to glycerol plus trehalose. Trehalose added group showed higher percentages of sperm motility, stability of chromatin structure than glycerol only. In this study, we suggest that trehalose is effective in reducing freezing damage to miniature pig sperm and can reduce chromatin damage during cryopreservation.

• Journal of Life Science
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• v.23 no.9
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• pp.1133-1139
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• 2013

During the collection of boar semen, bacterial contamination usually occurs. The contamination has deleterious effects both on semen quality and on sow fertility. The majority of contaminants are gram-negative bacteria, especially Serratia marcescens. In this study, we developed a PCR assay for the identification of S. marcescens targeting the luxS gene (GenBank no. EF164926). S. marcescens yielded a specific 306 bp PCR product. However, no amplification was observed in the other strains tested. The detection limit of PCR was $50pg/{\mu}l$ of template DNA of S. marcescens. The antimicrobial susceptibility patterns of S. marcescens isolated from boar semen were tested using the disk diffusion method. Gentamicin, ceftiofur, florfenicol, and neomycin showed high sensitivity in this test. The minimum inhibitory concentration (MIC) was also determined by the broth microdilution method. The $MIC_{90}$ values of ceftiofur, enrofloxacin, gentamicin, and neomycin were 8, 8, 8, and $16{\mu}g/ml$, respectively. These results indicate that PCR amplification of the luxS gene is a reliable and effective method for the identification of S. marcescens and that ceftiofur, enrofloxacin, gentamicin, and neomycin are effective semen extenders for controlling S. marcescens.

• Korean Journal of Animal Reproduction
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• v.23 no.3
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• pp.257-262
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• 1999

This study was carried out to evaluate the effect of pH and storage temperature on the viability of boar sperm diluted with extender KpA for swine artificial insemination. The results obtained in this experiment were summarized as follows : 1. The viability of boar sperm diluted with KpA was higher than that with BTS during storage and especially more than 60% of sperm viability in KpA was maintained through 6 days. The pH values of all extenders were kept during storage of semens following dilution. 2. The sperm diluted with acidic (pH 6.3~6.8) or alkalic (pH 7.8~8.0) KpA and stored at 4$^{\circ}C$ or 37$^{\circ}C$ were more sensitive in viability than that with neutral pH (6.8~7.3) and at 17$^{\circ}C$ storage. But pH values of all conditions were not increased rapidly. Especially acidic and alkalic diluents were more stable in pH after dilution. Conclusively, extender pH and storage temperature was the important factors for sperm viability. The KpA setting up around neutral pH was the optimal boar semen extender for maintaining liquid semen at 17$^{\circ}C$.