• Korean Journal of Veterinary Research
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• v.61 no.4
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• pp.29.1-29.7
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• 2021

Resveratrol (RSV, 3,5,4'-trihydroxytrans-stilbene) protects sperm from cryo-induced damage in various animal and human species. In this study, we aimed to assess the effect of dog sperm cryoprotective extender containing RSV on the quality of post-thaw dog sperm. Sperm were collected from 4 Beagles and supplemented with different concentrations of RSV (0, 100, 200, and 400 µM). After thawing, apoptosis index, and reactive oxygen species (ROS) levels were assessed to determine post-thaw sperm quality. Dog sperm cryopreserved with 400 µM RSV showed significant improvement in post-thaw sperm quality with lower apoptosis index and ROS levels (p < 0.05). Our results showed that the supplementation of dog sperm cryoprotective extender with RSV at a concentration of 400 µM improved the post-thaw dog sperm quality in the term of sperm ROS production and apoptosis. In addition, we emphasize the necessity of testing the ROS levels and apoptosis index using flow cytometry to determine the quality of post-thaw semen.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.4
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• pp.486-494
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• 2006

In order to protect the spermatozoa against cold shock, hen egg yolk is widely used as a cryoprotective agent in semen freezing extenders for domestic animals. The protective action of yolk is largely presumed to be due to low density lipoproteins (LDL). The effects of LDL on sperm quality of bull and northern pike (Esox lucius) after freezing-thawing have been reported, but no study has been made to evaluate the effect of LDL on boar sperm motility and other characteristics. The experiment was carried out to investigate the effect of LDL on the freezing of boar sperm in 0.25 ml straws. The aim was to evaluate the quality of boar spermatozoa cryopreserved in the presence of LDL. Motility of semen cryopreserved in LDL was analyzed and compared to semen cryopreserved with Tris-citric acid-glucose (TCG) and Tris-citric acid-fructose (TCF), two basic freezing extenders containing egg yolk. Similarly, acrosome and plasma membrane integrity were also evaluated and compared to semen cryopreserved with TCG and TCF. Analysis of sperm quality after freeze-thaw showed that the motility, acrosome and plasma membrane integrity were improved with LDL in the extender, as compared to the TCG and TCF. The highest post-thaw integrity of acrosome and plasma membrane and motility were obtained with 9% LDL (w/v). Consequently, the optimum LDL concentration in the extender was 9%. It is also suggested that the concentration of LDL addition is important for the effect on boar sperm protection during freezing and thawing. The percentage of motile spermatozoa was significantly higher after freezing in 9% LDL than in TCG and TCF 54.4% versus 30.4% and 30.1% (p<0.05), respectively. The integrity of acrosome and plasma membrane were also significantly higher at 70.3% and 50.5% respectively with semen frozen in 9% LDL extender compared to TCG at 37.8% and 30.3% and TCF at 36.4% and 29.9%, respectively (p<0.05),. In conclusion, we propose that extender containing LDL extracted from hen egg yolk could be used as a cryoprotective media with a better efficiency than TCG and TCF. LDL improved boar semen quality, allowing better spermatozoa motility, acrosome and plasma membrane integrity after the freeze-thaw process. Furthermore, we found out that the extender with 9% LDL concentration significantly enhanced motility, acrosome and plasma membrane integrity of boar sperm after freezing and thawing.

• 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$^{\circ}C$.

• ETRI Journal
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• v.34 no.6
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• pp.838-846
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• 2012

This paper proposes a cost-effective hybrid-type power budget extender (PBEx) that can provide a high power budget of over 45 dB in an asymmetric 10-Gb/s Ethernet passive optical network (10/1G-EPON). The hybrid-type 10/1G-EPON PBEx comprises a central office terminal (COT) and remote terminal (RT) module supporting four channels and uses a coarse wavelength division multiplexing (CWDM) technology between the COT and RT for a reduction of fiber cost and efficient access network design. The proposed 10/1G-EPON PBEx can provide over a 40-km reach and 128-way split per CWDM wavelength with no modification of a legacy 10/1G-EPON system and can satisfy the error-free service in $10^{10}$ packet transmission.

• Journal of the Korean Wood Science and Technology
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• v.1 no.2
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• pp.11-15
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• 1973

This study was carried out to utilize sweet potato, and jerusalem artichoke flour as an extender of urea formaldehyde resin for plywood manufacture. The results obtained are summarized as follows: 1) In dry and wet test of plywood, sweet potato flour extended in urea formaldehyde resin was shown better strength than those of wheat flour. 2) Sweet potato flour was shown good results up to 200 percent extension in the dry test, and there was not shown significant difference between 100 percent and 150 percent extension in the wet test. 3) In the case of 100 percent extension, potato flour was shown best dry shear strength(400 psi) and sweet potato flour was shown best wet shear strength (212 psi).

• Textile Coloration and Finishing
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• v.9 no.5
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• pp.63-74
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• 1997

Polyurethane microcapsules were synthesized by interfacial polymerization in an aqueous poly(ethylene glycol) dispersion with ethylenediamine as chain extender of toluene diisocyanate in perfume oil using poly(vinyl alcohol) as the stabilizing agent. The effect of chemical structure on the average particle size and distributions, morphologies, and thermal properties to design microcapsules for the sustained release system was investigated. It came to be known that polyurethane microcapsules with ethylene diamine as chain extender had a rounder, more permeable and controlled release membranes. And the release test of polyurethane microcapsules with different soft segment content was done to certify the effect of long methylene chain. According to the higher molecular weight of polyether polyol, the release rate of microencapsulated disperse dye molecular was faster.

• Journal of Adhesion and Interface
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• v.10 no.4
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• pp.169-173
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• 2009

In this study, We were studied on the properties of polyurethane elastomer containing the polyol, chain extender and isocyanate in polyurethane elastomer. Polyurethane elastomer had the best properties with poly(tetramethylene) glycol for in-line skate wheel. With more incorporation of chain extender content in polyurethane elastomer, tensile strength and hardness increased and elongation decreased. And then properties of polyurethane elastomer with the bulky type isocyanate had better than the flexible type isocyanate.

• Elastomers and Composites
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• v.54 no.4
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• pp.279-285
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• 2019

Bio-based polyester polyols were synthesized using esterification with azelaic acid, sebacic acid, and 1,3-propanediol. Polyurethanes were prepared using chain extenders (1,4-Butanediol, 1,3-Propanediol, and isosorbide) and 4,4'-diphenylmethane diisocyanate with a mixing ratio of 1:1:1.1. Subsequently, the properties of the polymers prepared using the different chain extenders were compared. The synthesis of polyurethane was confirmed by FT-IR, TGA, and GPC. The mechanical properties (hardness, ball rebound, and tensile strength) of the materials were analyzed using shore A tester, taber abrasion, and UTM. heat, chemical, and water resistances of the prepared materials were measured by comparing the tensile strengths according to external changes.

• Journal of the Korean Wood Science and Technology
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• v.3 no.1
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• pp.16-19
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• 1975

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.5
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• pp.646-651
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• 2016

Cryopreservation of caudal epididymal spermatozoa is an effective technique to conserve genetic potentials of superior dogs when it is not possible to collect ejaculated spermatozoa. Although hen egg yolk is commonly supplemented into the semen extender, active substances within the egg yolk which protect sperm against cryoinjury remain to be discovered. Among its compositions, low-density lipoprotein (LDL) has been reported to have a cryoprotective property for sperm cryopreservation. However, the effects of LDL on dog epididymal spermatozoa during cryopreservation have not yet been investigated. This study aimed to investigate the effects of LDL on epididymal spermatozoa quality following cryopreservation and thawing. After routine castration of 12 dogs, caudal epididymides from individuals were separated from the testes and cut into a few pieces in a Tris-buffer. Spermatozoa recovered from each sample were examined at once for sperm quality and divided into six groups of extender: no LDL, 20% egg yolk, 4%, 8%, 16%, and 24% LDL, before cryopreservation. The sperm aliquots were then equilibrated and conventionally frozen. After thawing, sperm motility, morphology, plasma membrane integrity, and acrosome integrity were evaluated. The results revealed that 4% LDL and 20% egg yolk yielded significantly higher sperm motility (57.69% and 52.69%, respectively, p<0.05) than other LDLs. In addition, 4% LDL yielded the significantly highest plasma membrane integrity (70.54%, p<0.05). In conclusion, the supplementation of 4% LDL in Tris-glucose extender could be applied for cryopreservation of canine epididymal spermatozoa.