• Journal of Energy Engineering
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• v.14 no.2 s.42
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• pp.153-158
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• 2005

In order to investigate the short-term performance of polyethylene electrofusion joints, the mechanical tests and stress analysis have been conducted to the artificially defected weld joints. The defects of lack of fusion with a square-type were fabricated with 10, 20, 30, 40, 50, 60$\%$ size of the width of heat-ing wire zone, respectively. In this defect sires range, both tensile and bending test results showed the dependence of defect size to the electrofusion joints performance, but both sustained pressure and crush test results didn't. The numerical stress analysis results including the soil and internal pressures, tensile and bend-ing stresses clearly showed the dependence of fusion defect size. Based on both mechanical test and stress analysis results, the maximum acceptable defect size in polyethylene electrofusion joints is discussed.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.6
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• pp.641-645
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• 1995

This study was conducted to develop a method for production of nuclear transplant bovine embryos using in vitro-matured (IVM) oocytes and to examine the effect of different conditions of electrofusion on fusion rate and developmental capacity of donor nucleus transplanted to enucleated oocytes. Eight- to sixteen-cell embryos derived from oocytes matured and fertilized in vitro used as donor blastomeres and IVM oocytes were used as recipient oocytes. Oocytes were enucleated immediately after 23-24 h IVM and then reconstituted with a donor blastomere in two different micromanipulation media. Fusion rate and subsequent development of the reconstituted oocytes was compared under the different electric stimuli and recipient oocyte ages. Success rate of enucleation was significantly higher in TCM-199 medium containing FCS than in DPBS. The high fusion rate(75-94%) and development (6.4-14.8%) to morulae and blastocyst (M + B) were obtained from 0.6-0.75 kV/cm DC voltage, although total cleavage was not different among the electric pulses. Most optimal condition of electric stimulation for fusion and development was 1 DC voltage of 0.75 kV/cm, in which 80.5% of oocytes were fused, 80.0% and 31.7% of which was cleaved and developed to M + B, respectively. No M + B was obtained from 1.2 kV/cm DC voltage regardless of pulse frequency. Recipint oocyte age at electrofusion greatly affected the cleavage and subsequent development to M + B, showing high rate at 40-41 h oocyte maturation. These results suggest that a suitable condition of electrofusion for donor nuclei derived from IVF may be 1-2 DC pulses of 0.7 kV/cm for $70{\mu}sec$ and that processing of a transplanted nucleus in IVM oocytes may be affected by maturation age of recipient oocytes.

• Journal of Ocean Engineering and Technology
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• v.27 no.5
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• pp.93-98
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• 2013

Fuel gas is an important energy source that is being increasingly used because of the convenience and clean energy provided. Natural gas is supplied to consumers safely through an underground gas-pipe network made of a polyethylene material. In electrofusion, which is one of the joining methods used, copper wire is used as the heating wire. However, it takes a long time for fusion to occur because the electrical resistance of copper is low. In this study, therefore, electrofusion was conducted by replacing the copper heating wire with carbon fiber to reduce the fusion time and improve the production when joining large pipes. Fusion and tensile tests were performed after the electrofusion joint was made in the polyethylene pipe using carbon fiber. The results showed that the fusion time was shorter and the temperature inside the pipe was higher with an increase in the current value. The ultimate tensile strength of specimens was higher than that of virgin polyethylene pipe, except for polyethylene pipes joined using a current of 0.8 A. The best fusion current value was 0.9 or 1.0 A because of the short fusion time and lack of transformation inside the pipe. Thus, it was shown that carbon fiber can be used to replace the copper heating wire.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.121-128
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• 1997

A lactic acid bacterium was isolated from kimchi. The isolated strain was identified as the genus Lactobacillus through its morphological, cultural, and physiological characteristics and named as Lactobacillus sp. JC-7. The optimum conditions for the electrofusion between streptomycin (2.5 mg/ml) resistant mutant of Lactobacillus acidophilus 88 and kanamycin (600 $\mu$g/ml) resistant mutant of Lactobacillus sp. JC-7 were evaluated. The highest number of fusants were obtained at a capacitance value of 120 msec (1670 $\mu$F), a field strength of 100 V/cm, and a pulse controller setting of 72$\Omega$. The optimum pH of electroporation buffer was 7.5 and the concentration of divalent cation was 1 mM Mg$^{2+}. Electrofusants were efficiently obtained by addition 20% polyethylene glycol to elec- troporation buffer. The yield of fusion was better than that of using polyethylene glycol mediated chemical induction.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.82-85
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• 2007

내염성 조건에서 phytase를 생성하는 효모 균주를 개발하기 위하여 phytase를 생산하는 효모인 S. cerevisiae CY 균주와 내염성 효모인 Z. rouxii Y-80 균주 사이의 전기적 세포융합을 실시하였다. S. cerevisiae CY 균주의 Z. rouxii Y-80 균주의 배양된 세포를 1.0%의 ${\beta}$-mercaptoethanol로 전처리하고 Tunicase로 세포벽을 분해시킨 후 원형질체를 얻었다. 각 균주의 원형질체는 electrofusion 완충액에 1:1의 비율로 현탁한 후 AC 13V에서 30초간 처리하고 고전압(DC 500 V/100 ${\mu}sec$)을 가하여 전기적 세포융합을 실시하였다. 선별된 융합균주는 NaCl이 10% 첨가된 배지에서 친주들과 비교한 결과 Z. rouxii Y-80 균주보다는 생육면에서 25% 이상 증가하였으며, phytase 활성도는 친주인 S. cerevisiae CY 균주 대비 53%의 생성도를 확인하였다.

• Applied Biological Chemistry
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• v.36 no.6
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• pp.562-566
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• 1993

The conditions required for plant transformation through the electroporation system and for the electrofusion of the prtoplasts were investigated for geranium (Pelargonium zonale hybrids). The optimum condition for electroporation was 1.77 kV/cm for $40\;{\mu}sec$ under which 70% of the protoplasts were viable and 58% of the viable protoplasts were stained with methylene blue. The pBin19 DNA plasmid used as a carrier vector was isolated from E.coli $DH5{\alpha}$ strain, purified, identified by the electrophoresis on agarose gel and electroporated into the protoplasts. The KM8 liquid medium gave better cell division than any other media. One MHz of AC frequency with 40 V/cm of amplitude for 15 sec followed by 0.5 kV/cm of DC amplitude for $60\;{\mu}sec$ was most efficient for the electrofusion of protoplasts.

• 수도
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• s.69
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• pp.97-103
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• 1994

• Journal of Veterinary Clinics
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• v.13 no.2
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• pp.149-152
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• 1996

This study was carried out to evaluate the efficiency of production of cloned embryos by nuclear translatation (NT) when using 4-cell to compact morula stage embryos as nuclear donor. In micromanitulation and electrofusion of blastomeres from 4-cell to morula stage embryos, the successful injection rate was higher with late stage blastomeres, on the contrary the fusion rate was lower. The in vitro developmental rate of NT embryos was not significantly different between cell-stages of donor blastomeres. Although the overall rate of production of cloned embryos with 4-cell. 8-cell, early and late morula stage embryos was 14.0, 18.0, 15.3 and 14.1%, respectively, the mean number of blastocysts produced with a donor embryo was the most (4.51) with the compact morulae. Therefore, it can be suggested that the embryos at thelate stage is more beneficial for the mulciple production of cloned embryos, If the late stage blastomeres have maintained their totipotency to produce intact offspring.

• Journal of Plant Biotechnology
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• v.2 no.2
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• pp.109-113
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• 2000

Somatic hybrids were produced by electrofusion between embryogenic callus protoplasts of 'Syougun' mandarin and leaf protoplasts of grapefruit. Hybridity of the two plants was confirmed by leaf morphological characteristics and random amplified polymorphic DNA (RAPD) analysis. The cpDNA analysis using PCR-RFLP could not distinguish those of both parents. These plants showed normal growth and had chromosome number of 27. These unexpected triploid somatic hybrids might be derived from fused cells between diaploid protoplast of embryogenic calli and diploid protoplast of leaf, because polysomaty, a mixture of haploid cells and diploid cells was observed in the lactose medium-pretreated embryogenic calli of 'Syougun' by flow cytomehy analysis.

• Journal of Embryo Transfer
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• v.31 no.3
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• pp.207-213
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• 2016

The objective of this study was to investigate to influence of glutathione (GSH) on development and antioxidant enzyme activity in tetraploid porcine embryos. Tetraploid embryos were produced using parthenogenetic 2-cell embryo by electrofusion method. Tetraploid embryo development was observed every 24 hours and intracellular antioxidant enzyme activity was measured at 120 hours after electrofusion. The 4-cell to 16-cell stage tetraploid embryos was increased in 100 and $500{\mu}M$ GSH-treated groups compared control group at 48 hours (P < 0.05) but cleavage rates were not significantly different among the GSH treatment groups at 48, 72, 96, and 120 hours. Blastocyst formation was significantly increased by 300 and $500{\mu}M$ GSH at 120 hours in tetraploid embryos (P < 0.05). But blastocyst cell number were not significantly different among the GSH treatment groups ($16.4{\pm}0.8$, $16.8{\pm}2.6$, $18.5{\pm}2.8$ and $17.5{\pm}1.8$). The intracellular antioxidant enzyme level was increased in $500{\mu}M$ GSH compared to 0 and $100{\mu}M$ GSH (P < 0.05). We suggest that GSH may be improve development of tetraploid embryo in pigs.