• Toxicological Research
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• v.13 no.4
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• pp.371-376
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• 1997

To compare the severe liver damage with the slight one on the bromobeazene metabolism in rats, the animal group described as B7 group was induced the stage of slight liver damage with 7 times bromobenzene injection every other day (400 mg/Kg body wt. i.p.), whereas B40 group was induced that of more severe liver damage with bromobeazene 40 times injection as identified with determination of serum levels of alanine aminotransferase(ALT) activity and the histopathological findings. In the present experimental animal model, the decreasing rate of glutathione(GSH) and the increasing rate of glutathione S-transferase activity to the control group were higher in B7 group than B40 group. Furthermore the single dose of bromobenzene was injected to the two groups and sacrificed at 8hr and the hepatic aniline hydroxylase(AH) activity, GSH content and GST activity were determined. The increasing rate of AH activity to the control was lower in B40 group than B7 group and the decreasing rate of GSH to the control was also lower in B40 than B7 group. Moreover, B7 group showed the increased activity of hepatic GST to the control whereas B40 group showed the decrease activity of the enzyme. And Vmax value in GST was more decreased in B40 group than B7 group.

• Journal of the Korean Society of Combustion
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• v.20 no.4
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• pp.26-33
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• 2015

American NREL (National Renewable Energy Laboratory) reported that BD20 could reduce PM, CO, SOx and cancerogenic matters by 13.6%, 9.3%, 17.6% and 13% respectively, compared to diesel fuel. BD20 has been being tested on garbage trucks and official vehicles at Seoul City, which is positive on air environment, but negative on combustion by higher viscosity in winter season. This study investigated the combustion characteristics by employing multi cavity piston for improving the deterioration of combustibility caused by the higher viscosity of the biodiesel fuel such as BD20 with the combustion flames taken by a high speed camera and the cylinder pressure diagram. A 4-cycle single cylinder diesel engine was remodeled to a visible 2-cycle engine for taking the flame photographs, which has a common-rail injection system. The test was done at laboratory temperature of about $4{\sim}5^{\circ}C$.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.61-61
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• 2001

The main goal of this study was to produce transgenic piglets by the method of injection of sperm-mediated exogenous DNA. Spermatozoa (1$\times$106 sperm of final concentration) obtained from caudal epididymis were mixed with pBC1-hEPO (20 ng/${mu}ell$) or pcDNA3 LAC Z (20 ng/${mu}ell$), and followed by electroporation (500 V, 25 ㎌). Matured oocytes having the first polar body and dense cytoplasm were selected and centrifuged at 12,000g for 6 min. After sperm injection, the oocytes were activated electrically (1.7 ㎸/cm, 30 $\mu$ sec, single pulse) in 0.3 M mannitol solution. Eggs injected sperm were cultured in NCSU 23 medium (0.4% BSA) at 39$^{\circ}C$, 5% $CO_2$ in air for 192 h. This study were comprised 3 experiments. Experiment 1 compared the developmental efficiencies between the sperm-injected oocytes (Group 1) and further activated electrically (Group 2). Experiment 2 compared the expression of pcDNA3 LAC Z in the embryos produced by Group 1 and Group 2. Finally, experiment 3 carried out transfer of embryos (1-8 cell stage) transfected with pBC1 -hEPO into surrogate recipients synchronized by injection of combination of PG600 with hCG. The rates of cleavage and development into blastocyst stage in Group 2 were significantly higher than those of Group 1 (71.3% and 28.1% vs. 43.3% and 10.3%, respectively, p<0.05). Thirty (24.2%) out of 124 embryos analyzed in Group 2 were positive by X-gal. Similarly, in Group 1, 16.3% (8/49) were positive. After transfer of 789 embryos to 7 recipient gilts, three out of them examined by ultrasound became pregnant. One recipient is in day 50 pregnancy. On day 54 of gestation, two were carried out uterotomy in order to confirm the pregnancy One had 7 and another had 2 fetuses. We conclude that injection of sperm-mediated gene transfer will be used as a valuable tool for the production of transgenic piglets.

• Animal cells and systems
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• v.16 no.2
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• pp.127-134
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• 2012

We investigated the effects of fadrozol, an aromatase inhibitor (AI), and $17{\alpha}$-methyltestosterone (MT) on the induction of sex change in juvenile longtooth grouper $Epinephelus$ $bruneus$, via histological observation of gonads. Changes in the mRNA expression of GtH subunits (FSH-${\beta}$ and LH-${\beta}$) in the pituitary, and estradiol-$17{\beta}$ (E2) and 11-ketotestosterone (11-KT) levels in the blood were also surveyed after AI and MT treatment. Juvenile longtooth groupers ($113{\pm}17g\;body\;weight$; $16.2{\pm}1.2cm\;body\;length$) received intramuscular injections of AI at 3 (3-AI) and 5 (5-AI) mg/kg BWdoses and MT at a 5 mg/kg BW (5-MT) dose. At week 7 post-injection, 3-AI and 5-MT oocytes were degenerated, and gonads of the 5-AI group initiated spermatogenesis. At week 21 post-injection, 3-AI- and 5-MT-treated gonads contained spermatogonia and spermatocytes, while 5-AI treatment induced advanced stages of spermatogenesis. The serum E2 level showed no significant differences throughout the experimental period, whereas that of 11-KT was significantly elevated in the 5-AI group at weeks 7 and 21 post-injection. A significant increase in the expression of FSH-${\beta}$ mRNA was evident in the 5-AI group at week 21 post-injection. In contrast, LH-${\beta}$ mRNA expression did not significantly differ among groups during the experimental period. These results imply that sex change has two stages in the longtooth grouper. In the first stage, oocytes are degenerated by the stimulation by 11-KT, and in the second stage spermatogenesis occurs, owing to the co-effects of 11-KT and FSH-${\beta}$.

• Korean Journal of Veterinary Research
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• v.30 no.2
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• pp.123-127
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• 1990

By nuclear transplantation technology twenty eight mice have been produced after transfer of heterozygous biparental eggs. Also heterozygous gynogenetic eggs with two female pronuclei and heterozygous androgenetic eggs with two male pronuclei have been obtained by injecting a male or female pronucleus with Sendai virus into the perivitelline space of enucleated haploid zygotes at pronuclear stage. The success rate of enucleation, karyoplast injection and fusion of both the pronuclei was 80.3, 83.4 and 81.8%, respectively. The overall pronuclei fusion rates by this technique were 56, 50 and 56% in biparental, gynogenetic and androgenetic eggs, respectively. The evidence was ascertained that the gynogenetic and androgenetic eggs were also able to develop in vitro up to blastocyst stage, even though their developmental potential was greatly diminished beyond 2-cell stage. The gynogenetic eggs were able to develop in vivo up to day 10 of pregnancy, while the androgenetic eggs failed to develop in vivo during the same period.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.3
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• pp.419-430
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• 1999

Measurements of local blowing ratio and ammonia-diazo flow visualizations have been conducted for a shower-head film cooling on a first-stage turbine stator. In this study, six rows of normal holes are drilled symmetrically on the semicircular leading edge of a simulated blunt body. The measurements show that for an average blowing ratio based on freestream velocity, M, of 0.5, local average mass flow rate through the first two rows of the holes is less than those through the second and third two rows of the holes, and the fraction of mass flow rate through the first two rows to total mass flow rate has a tendency to increase with the increment of M. The flow visualizations reveal that the injection through the first two row results in inferior film coverage even In the case of M = 0.5, meanwhile the row of holes situated at farther downstream location provides higher film-cooling performances for all tested M. This is because film-cooling effectiveness depends on local mainflow velocity at the hole location as well as the mass flow rate through each row.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.947-949
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• 1998

In this paper, the NO was oxidized $NO_2$ by using the non-thermal plasma and NOx removal characteristics were measured by showering NaOH water-solution to $NO_2$. The NO oxidation increased in the order of DC, AC, and Pulse. NOx oxidation for two stage with applied voltage was better than that for one stage with applied voltage. NO oxidation didn't depend on applied voltage. While NO oxidation was going on, NOx removal efficiency was 20-25%, however, significantly depended on the injection method of air and $H_2O$ + air. When NaOH water-solution density of 20% was showered to flue gases, NOx removal efficiency increased to 64%.

• The Journal of the Korean dental association
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• v.22 no.9 s.184
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• pp.771-780
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• 1984

To observe the healing process of the gingival wound in diabetic condition, the author induced diabetes mellitus by intravascular injection of streptozotocin in rat tail vein and made fresh wound in rat mandibular posterior gingiva using scalpel. The healing processes of gingival wound were examined periodically by light microscopy. The results were as follows. 1) The healing was completed at second week in control group, but it delayed until fourth week in experimental group and the organization was persisted for first two weeks. 2) The inflamed gingiva of dibetic rat demonstrated scanty polymorphonuclear lerkocytic infiltration at the early stage of experiment, but it soon became numerous as in cotrol group and the lymphocytic infiltrations were same degree as in control group. 3) The tissue destruction was broader in the experimental group than in the control group. The epithelization was began at the early stage of healing and the epithelial attachment was reformed with the completion of the wound healing. 4) Loss of Sharpey's fibers and destruction of cementum and alveolar bone were observed with the inflammatroy reaction, but these were reformed with the completion of the wound healing.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.4
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• pp.223-228
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• 2010

The collecting duct endothelin (ET) system, which involves ET-1 and its two receptors, may play a role in the regulation of renal sodium in association with the nitric oxide synthase (NOS) system. We determined whether sodium retention is associated with changes in the endothelin and NOS systems at different stages (i.e., a sodium retaining stage and a compensatory stage) of nephrotic syndromes. On day 7 after puromycin aminonucleoside (PAN) injection, urinary sodium excretion was decreased, ascites had developed, and there was a positive sodium balance. ET-1 mRNA expression was increased in the inner medulla of the kidney, whereas protein expression of ET receptor type B ($ET_BR$) was unchanged. The expression of neuronal NOS (nNOS) was decreased in the inner medulla. On day 14, urinary sodium excretion was unchanged compared with controls. The expression of $ET_BR$ increased, while nNOS expression in the inner medulla was comparable to controls. These findings suggest that decreased nNOS plays a role in the development of sodium retention in the nephrotic syndrome. Recovery of nNOS and increased renal $ET_BR$ synthesis may promote sodium excretion in later stages of the nephrotic syndrome (on day 14).

• 대한공업교육학회지
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• v.34 no.2
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• pp.321-330
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• 2009

This study presents the blow molding of injection stretch-blow molding process for PET bottle. The numerical analysis of the blow molding of PET bottle is considered in this paper using CAE with a view to minimize the thickness difference. In order to determine the design parameters and processing conditions in blow molding, it is very important to establish the numerical model with physical phenomenon. In this study, a shell model with thickness has been introduced for the purpose and blow simulations with 3-type blow process condition are carried out. The simulations resulted in the thickness distribution in good agreement with the physical phenomenon. Also, from the result of numerical analysis, we appropriately predicted the thickness distribution along the PET bottle wall and Using the result of numerical analysis we apply the preform design and blow molding process condition for optimization.