• Journal of Life Science
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• v.26 no.3
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• pp.376-386
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• 2016

Apoptosis induction has been proposed as an efficient mechanism by which malignant tumor cells can be removed following chemotherapy. The intrinsic mitochondria-dependent apoptotic pathway is frequently implicated in chemotherapy-induced tumor cell apoptosis. Since DNA-damaging agent (DDA)-induced apoptosis is mainly regulated by the tumor suppressor protein p53, and since more than half of clinical cancers possess inactive p53 mutants, microtubule-damaging agents (MDAs), of which apoptotic effect is mainly exerted via p53-independent routes, can be promising choice for cancer chemotherapy. Recently, we found that the apoptotic signaling pathway induced by MDAs (nocodazole, 17α-estradiol, or 2-methoxyestradiol) commonly proceeded through mitotic spindle defect-mediated prometaphase arrest, prolonged Cdk1 activation, and subsequent phosphorylation of Bcl-2, Mcl-1, and Bim in human acute leukemia Jurkat T cells. These microtubule damage-mediated alterations could render the cellular context susceptible to the onset of mitochondria-dependent apoptosis by triggering Bak activation, Δψm loss, and resultant caspase cascade activation. In contrast, when the MDA-induced Bak activation was inhibited by overexpression of anti-apoptotic Bcl-2 family proteins (Bcl-2 or Bcl-xL), the cells in prometaphase arrest failed to induce apoptosis, and instead underwent mitotic slippage and endoreduplication cycle, leading to formation of populations with 8N and 16N DNA content. These data indicate that cellular apoptogenic mechanism is critical for preventing polyploid formation following MDA treatment. Since the formation of polyploid cells, which are genetically unstable, may cause acquisition of therapy resistance and disease relapse, there is a growing interest in developing new combination chemotherapies to prevent polyploidization in tumors after MDA treatment.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.27-34
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• 2017

Our aim was to find the effective duration and culture conditions for microspore culture in a genetically variant cabbage (Brassica oleraceae L. var. capitata). We discovered that the '$2{\times}NLN$ medium containing $AgNO_3$ 1 mg/l, sucrose 13%' was most efficient in producing the cabbage embryos. The number of induced embryos was higher in $F_2$ or $F_3$ progeny generation than the $F_1$ hybrid cultivar used as plant materials. Thus, we recommend microspore culturing using progeny plants of failed $F_1$ cultivar. The acquisition ratio of embryos and plants derived from microspore was higher in the early flowering period as compared to the late flowering period. When transplanted in the soil, 71.2% plants developed from the early flowering period, compared to 27.0% from the middle period and 1.8% plants from the late period. Thus, we recommend microspore culture using buds collected during the early flowering period.

• The Korean Journal of Zoology
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• v.30 no.1
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• pp.89-98
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• 1987

The research of fused oocytes was conducted to investigate the in vitro mejotic maturation of immature oocytes (GV oocytes) fused with oocytes in germinal vesicle breakdown (GVBD oocytes) in the presence of dbcAMP which is known as one of the strong inhibitors to GVBD. The immature oocytes fused together as well as those fused with GVBD oocytes proceeded to GVBD in 3 hr culture in plain medium. But in the medium containing dbcAMP (100$\mu$g/ml), the immature oocytes fused together did not show any GVBD and thus the fusion itself could not affect the inhibitory activity of dbcAMP. However, all of the immature oocytes fused with GVBD oocytes underwent GVBD in 3 hr culture despite of the presence of dbcAMP. When the culture was extended to 20 hr, nearly all of the immature oocytes fused together were still arrested at the GV stage in the presence of dbcAMP. But most of the fused oocytes which had shown GVBD during 3 hr culture developed to metaphase II stage extruding one or two polar bodies regardless of the presence of dbcAMP. In this experiment, it was found that two sets of the metaphase chromosomes were somewhat concomitant with a pair of the polar bodies in the fused egg. Upon the results of the present studies, it is assumed that there may be a maturation promoting factor(s) in the cytoplasm of the GVBD occytes, and this factor(s) possibly nullifies the function of dbcAMP.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.743-747
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• 2003

Tests show that the growth of lactic bacteria in kimchi varies according to the type and concentration of salt used. Weissella confusa, the early stage bacteria in kimchi fermentation, increased sharply after 5 hr of induction with 3% light salt and refined salt. However, the induction period lengthened to 12 hr with 3% sea salt and bamboo salt. Lactobacillus delbrueckii ss lactis and L. pentosus which grow in the middle stage of fermentation, and L. hamsteri, which grows at the end stage of fermentation, were found after 12 hr of induction with 3% salt of all kinds. When 5% light salt was added to the culture medium, the induction period of bacteria other than W. confusa lengthens to 12 hr. The trend is similar for sea salt, bamboo salt, and refined salt, with a higher NaCl concentration resulting in less growth. W. confusa showed salt tolerance, but L. hamsteri was affected by the type and concentration of salt. With 5% sea salt, bamboo salt, and refined salt, the growth of bacteria was inhibited by up to 24 hr.

• YAKHAK HOEJI
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• v.31 no.1
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• pp.19-24
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• 1987

In order to find out the pharmacologically active but less toxic compounds than piperine, the actions of several amide derivatives of 5-phenyl-2, 4-pentadienoic acid on the CNS depressant activities were examined. The nine amide derivatives were investigated by using ICR mice as an experimental amimals on acute toxicities, anticonvulsant, sedative, analgesic and antipyretic effects. In the case of acute toxicities, all derivatives were weaker than piperine except compound III. Compound I showed strong anticonvulsant activity. On the other hand, compound I, III and IV significantly prolonged the sleeping time induced by hexobarbital in mice. Compound I, III and IV exhibited better analgesic effect than aspirin while compound II, V, VII and IX showed similar antipyretic activity to aspirin.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.117-122
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• 1996

본 연구에서는 2개사에서 제조된 합금 600 및 합금 690 이음매 없는 관과 진공 유도 용해로 제조한 합금 690 판재에 대하여 부시 환경의 변화에 따른 특성 평가를 행하였다. 부식 평가는 양극 분극 시험을 통하여 행하였으며 부식 환경은 NaCl, HCl, NaOH(＋$Na_2$SO$_4$) 용액 및 Cu$^{＋}$/Cl$^{－}$ SO$_4$$^{2－}$ 용액이었다. 합금 600 및 합금 690의 양극 분극 저항성을 부식 환경에 따라 평가한 결과, 부식 용액의 종류에 따라 서로 다른 분극 거동을 보이고 있으며, 합금 690의 저항성이 합금 600의 저항성보다 우수하게 나타났다. 또한 가성 용액 중에 $Na_2$SO$_4$를 첨가할 경우 부식 속도를 가속화시키고 있다. 한편 Mo이 첨가되지 않은 합금 690M0의 경우는 Cl$^{－}$ SO$_4$$^{2－}$ 비가 증가할수록 공식 저항성이 급격히 감소하고 있으나, Mo이 첨가된 합금 690M2의 경우는 시험한 전체 비율에서 이온의 영향을 받지 않는 것으로 나타나고 있어 합금 690의 공식 저항성에 Mo이 매우 좋은 효과를 보이고 있음을 알 수 있다.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.103-108
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• 1999

The paper describes a implementation of space vector pulse-width modulation voltage source inverter and interfacing of DSP using field programmable gate array(FPGA) for a induction motor vector control system. The implemented chip is included logic circuits for SVPWM, dead time compensation and speed detection using Quick Logic, QLl6X24B. The maximum operating frequency and delay time can be set to 110MHz and 6 nsec. The designed Application Specific Integrated Circuit(ASIC) for SVPWM can be incorporated with a digital signal processing to provide a simple and effective solution for high performance induction motor drives with a voltage source inverter. Simulation and implementation results are shown to verify the usefulness of ASIC in a motor drive system and power electronics applications.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.466-468
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• 2005

Recently, the demand for the development of high quality and high speed laser printer and efficient power utilizations are required. Among complicate electro-mechanic devices in laser printer, the toner fusing unit consumes above 90[%] of all electrical energy needed for printing devices. Therefore, the development of more effective energy-saving toner fusing process becomes a significant task of much great demand. Generally, there are several way to implement fusing unit, among them this paper present a new hybrid induction heating method. The proposed induction heating method enables to increase coupling coefficient between heating coil and heat roller also to Increase total energy transfer efficiency. Therefore the proposed IH inverter system provide very fast W.U.T.(Warm UP Time), also high efficiency. Through experimental result, the proposed control system is verified.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1377-1380
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• 2000

본 논문은 산업자원부 중기거점기술개발사업의 일환인 '전동차 추진장치 기술 개발 과제'로 개발된 전동차 구동 시스템에 대하여 서술하고 있다. 개발된 전동차 구동 시스템은 4대의 210kW 유도전동기를 병렬로 구동하며 주 전력 소자로 IGBT(Insulated Gate Bipolar Transisotr)를 사용하여 스너버 회로가 없는 간단하고 신뢰성 있는 시스템을 구현하였다. 제어 기법으로는 벡터 제어 기법을 적용하여 저속 기동 및 가속시의 토오크 제어 특성을 향상시켰다. 본 논문에서는 전체시스템의 구성 및 특성을 약술하고, 적용된 벡터제어에 대하여 논하였다. 그리고 본 과제를 위해 새로 제작된 전동차 1편성을 이용하여 한국철도차량주식회사 상주공장의 시험 전차선에서 주행 시험을 실시한 결과 개발된 전동차 구동 시스템의 성능이 목표 사양을 만족함을 확인하였다.

• Journal of Radiation Protection and Research
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• v.22 no.1
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• pp.1-7
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• 1997

Radiation protection by post-irradiation injection of the ginseng extract in mice was studied. Male ICR mice, 7 weeks old, were orally injected with ginseng extrat(100mg/kg) for 10 days, and with physiologocal saline as the control. Immediately after final injection, mice were whole body irradiated with 5.08Gy(Cs-137 ${\gamma}$-ray, central dose rate : 654Gy/h) which induced Bone marrow death. At 24h after irradiation, micronucleus test and metaphase analysis in bone-marrow were carried, blood cell were counted and the survival rate were carried for 30 days after the irradiation. Stimulated recovery by the extract was observed in thrombocyte count, but that phenomenom was not showed in the erythrocyte and leucocyte counts. The 30-day survival ratio was 5% and 65% for the control and experimental group. Frequencies of micronuclei per 1000 polychromatic erythrocytes were 79.5${\pm}$1.5 in experimental group, 185.9${\pm}$35.8 in control. And Abnormal chromosomes per 50 metaphases were 112 in experimental group and 143 in control.