• Journal of Animal Science and Technology
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• 제48권6호
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• pp.847-860
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• 2006

본 시험은 n-6 및 n-3 계열 다중불포화지방산 함량이 풍부한 사료원을 Charolais 거세우에게 각각 사료 급여기간을 달리하여 급여하였을 때 근내 지방산 조성을 조사하기 위하여 수행하였다. 시험 수행은 영국 IGER (Institute of Grassland and Environmental Research) 연구소 육우 사양실험실에서 실시 하였으며, 공시축은 총 28두 Charolais 거세우로서 ad libitum으로 조사료 급여를 하였다. 그리고, 두 개의 지방원료원으로서 C18:2 n-6 함량이 풍부한 대두와 C18:3 n-3함량이 풍부한 아마종실을 60일 및 90일간 공급하였으며, 농후사료는 총 건물섭취의 73%으로 하였다. 도체중, conformation 및 fatness score는 60일 사료급여구와 비교하여 90일 사료급여구에서 높게 조사되었다(P<0.05). 공시축의 m. longissimus thoracis의 중성지방내 총지방산 함량은 지방원료원에 의한 영향은 없었지만, 반면에 인지질 내 총지방산 함량은 아마종실 급여구에 대략 15% 높게 나타났다(P<0.05). 근육 중성지방 내 C18:3 n-3와 cis-9, trans-11 CLA 함량은 아마종실급여구에 유의성있게 높게 조사되었으며(P<0.001), 반면에 C18:2 n-6 함량은 대두 급여구에서 높았다 (P<0.001). 근육 인지질 내 CLA와 C18:3 함량은 아마종실급여구에 높게 나타났으며, C18:2 n-6 함량은 대두 급여구에 높았다. 한편, 근육 중성지방 내 C14:0, C16:0, C16:1, CLA, C18:1 n-9, C18:2 n-6 및 C18:3 n-3 함량은 90일 사료급여구에서 높게 조사되었다. 근내 불포화지방산:포화지방산 비율은 사료급여기간에 영향을 받지 않았지만, C18:2 n-6:C18:3 n-3 비율과 n-6:n-3 불포화지방산 비율은 아마종실 급여구에서 높게 나타났다. 따라서 본 시험은 대두 혹은 아마종실 같은 사료급여와 급여기간에 의하여 쇠고기 근내 불포화지방산 함량을 변화 시킬 수 있음을 보여주고 있다. 그리고, 아마종실 급여는 쇠고기 내 지방산 함량이 조성이 인체 건강과 관련한 영양적 지표에 보다 바람직한 것으로 증명되었다.

• Korean Chemical Engineering Research
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• 제57권6호
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• pp.868-873
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• 2019

본 연구에서는 유기물인 메틸 바이올로겐(methyl viologen, MV)과 템폴(4-hydroxy-TEMPO, TEMPOL)을 활물질로 사용하고 NaCl의 중성 전해질 기반 수계 유기 레독스 흐름전지 성능이 멤브레인에 따라 어떻게 영향을 받는지 분석하였다. 메틸 바이올로겐(MV)과 템폴(TEMPOL)은 중성 전해질인 염화나트륨(NaCl) 전해질에 대해 높은 셀전압(1.37 V)을 얻을 수 있다. 성능 비교를 위해 사용한 멤브레인은 두 가지이다. 첫째로, 상용 양이온 교환막 중 하나인 Nafion 117를 사용하였을 때 성능은 첫번째 사이클에서 충전만 일어났을 뿐 그 후 높은 저항 때문에 완전지가 작동하지 않았다. 하지만 두번째로 사용한 Fumasep 음이온 교환막(FAA-3-50)은 Nafion 117 멤브레인을 사용했을 때와는 다르게 비교적 안정적인 충방전 사이클링을 보였다. 전류 밀도 $40mA{\cdot}cm^{-2}$, 컷-오프 전압 0.55~1.7 V에서 전류 효율(charge efficiency)은 97%, 전압 효율(voltage efficiency)은 78%로 높게 나타났다. 방전 용량(discharge capacity)은 10사이클에서 $1.44Ah{\cdot}L^{-1}$로 이론 용량($2.68Ah{\cdot}L^{-1}$)의 54%를 나타내었다. 방전 용량의 용량 손실율(capacity loss rate)은 $0.0015Ah{\cdot}L^{-1}/cycle$ 로 나타났다. 순환주사전류 실험을 통해 Nafion 117 멤브레인과 Fumasep 음이온 교환막 사이의 이러한 성능차이는 활물질의 크로스 오버(cross over) 현상으로 인한 방전 용량 손실이 아닌 멤브레인과 활물질의 화학적 반응으로 인한 저항 증가가 원인임을 파악할 수 있었다.

• Corrosion Science and Technology
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• 제18권6호
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• pp.300-311
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• 2019

The corrosion behaviors of twinning-induced plasticity (TWIP) steels with different alloying elements (Cu, Al, Si) in a neutral aqueous environment were investigated in terms of the characteristics of the corrosion products formed on the steel surface. The corrosion behavior was evaluated by measuring potentiodynamic polarization test and electrochemical impedance spectroscopy. For compositional analysis of the corrosion products formed on the steel surface, an electron probe x-ray micro analyzer was also utilized. This study showed that the addition of Cu to the steel contributed to the increase in corrosion resistance to a certain extent by the presence of metallic Cu in discontinuous form at the oxide/steel interface. Compared to the case of steel with Cu, the Al-bearing specimen exhibited much higher polarization resistance and lower corrosion current by the formation of a thin Al-enriched oxide layer. On the other hand, Si addition (3.0 wt%) to the steel led to an increase in grain size, which was twice as large as that of the other specimens, resulting in a deterioration of the corrosion resistance. This was closely associated with the localized corrosion attacks along the grain boundaries by the formation of a galvanic couple with a large cathode-small anode.

• 에너지공학
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• 제11권4호
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• pp.370-379
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• 2002

우리나라에서 전력 공급의 40％ 이상을 차지하는 원자력 발전의 중요성은 더 말할 나위가 없으나 방사성 폐기물 관리 시설의 운영 지연이 안정적인 원자력 발전에 저해 요소로 작용할 우려가 있다. 정부 당국의 정책적 배려, 방사성폐기물 관리 사업 주체의 노력, 관련 기술의 축적에도 불구하고 방사성 폐기물관리 사업은 가시적인 진전이 없는 상태이다. 그러므로 우리나라는 과거 어느 때보다도 더욱 효율적인 정책 기획과 집행으로 방사성폐기물을 관리해야 하는 시점에 처해 있다고 할 수가 있다. 본 연구는 이러한 배경에서 과거의 정책을 평가하고 미래를 위한 새로운 방사성폐기물 관리 정책을 모색한 결과 연구 개발. 부지 선정. 시설 건설. 운영, 폐쇄 후 감시에 이르는 전 과정에서 정책의 최우선 기조를 관리시설의 장기적인 안전성 확보에 두고, 안전 규제 기관의 참여 하에 공개적으로 입지를 추진해야 하며, 방사성폐기물 관리 사업과 이해 관계가 상충되지 아니하는 중립적인 위치의 공공법인체가 범국가적 차원에서 연구개발 조정 기능을 수행하여야 한다는 요지의 결론을 도출하였다.

• 생명과학회지
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• 제28권6호
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• pp.753-763
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• 2018

Cathepsin은 리소좀에 존재하는 효소로, 엔도좀-리소좀 경로를 통하여 손상된 단백질의 분해를 유도한다. 이러한 cathepsin은 활성화되는 촉매 잔기 위치(catalytic residue site)에 따라 cysteine, aspartate, serine cathepsin으로 나뉜다. 다양한 암세포에서 cysteine cathepsin은 유전자 증폭이나 전사, 번역, 전사 후 단계를 통해 높은 발현을 유지한다. 특히 cathepsin S의 경우, 다른 cysteine cathepsin과 달리 중성 pH 환경에서도 안정적으로 활성도를 유지하며 특정 조직에서 발현이 제한적이라는 특징을 가지고 있기 때문에 질병의 미세환경에서 중요한 역할을 한다. 면역세포에서의 cathepsin S는 불변 사슬(invariant chain)을 분해하여 항원 제시에 중요한 MHC class II의 활성화를 통해 면역 반응을 조절하며, 암세포에서의 cathepsin S는 전이와 혈관신생을 조절함으로써 암세포의 성장을 증가시키는 역할을 한다. Cathepsin S의 발현 조절에 문제가 생기면 암, 관절염, 심혈관 질환을 포함한 많은 병리학적 현상에 영향을 미친다. 특히 암세포에서 cathepsin S의 발현 억제와 결함은 혈관신생을 억제시킬 뿐만아니라, 암세포의 성장과 전이를 감소시키고 세포사멸을 유도한다. 따라서, cathepsin S는 암 치료에 있어 좋은 표적이 될 수 있다.

• 한국환경과학회지
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• 제4권2호
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• pp.121-139
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• 1995

Based on the Results of Marine Meteorological and Oceanographical Observations (1966 -1987), the phenomenon of chimney is found as a candidate for the formation of the Japan Sea Proper Water (JSPW). The chimney phenomenon occurs twelve times Inuring 1966∼ 1987. The water types in the chimney denoting the deep convection are similar to those of the JSPW 0∼ 1℃ in potential temperature, 34.0∼34.1 ‰ in salinity and 68∼80 cl/t in potential thermosteric anomaly from the sea surface to the deep layer. The static stabilities in the chimney stations are unstable or neutral. This indicates that the winter time convection occurs. The JSPW sunken from the surface layer of chimney in winter spreads out under the Tsushima Warm Current area, following the isosteric surface of about 76 cl/t in Potential thermosteric anomaly. The formation of the deep water of the JSPW is mainly affected by the cooling of the sea surface than the evaporation of winds because the temperature and the salinity on the isoteric surface of about 76 cl/t in potential thermosteric anomaly ate cold and low The phenomenon of chimney occurred in here and there of the area in the north of 40" 30'N, west of 138" E. This suggests that the deep water of the JSPW is formed not in a limited area but probably in the overall region of the northern open ocean.

• 전기학회논문지
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• 제58권3호
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• pp.431-436
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• 2009

As the telecommunication lines bring into widespread use, one of the most important aspects related to power distribution systems is effectively to evaluate the effect on the telecommunication lines from power lines. One of the efficient methods to evaluate the effect is to measure the induced voltage of a telecommunication line as a result of a ground-loop. If the power lines cause high induced voltage, the ground reference in the telecommunication lines is no longer a stable potential, so signals may ride on the noise. A ground loop is common wiring conditions where a ground current may take more than one path to return to the grounding electrode at the arrangement between the power lines and telecommunication lines. When a multi-path connection between the power lines and telecommunication line circuits exists, the resulting arrangement is known as a ground loop. Whenever a ground loop exists, there are potential for damages or abnormal operations of the telecommunication lines. The power lines can induce the voltage on the communication line. The effects can be calculated by considering the inductances and capacitances. However, if we assume that there are only power lines, it doesn't have a practical meaning because there are conductors with other purpose in the neighborhood of the lines. If we consider that case, we need more complex system. Therefore we suggest more complex system considering the conductors with other purpose in the neighborhood of the lines. The neutral wires and the overhead ground wires are considered for calculating the induced voltage. We assume that there are the messenger wires beside the power line as a result of increased use of them. The main purpose of this paper is a study on a shielding effect of messenger wires in the distribution lines. EMTP(Electro-Magnetic Transients Program) program is used for the induced voltage calculation.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.781-787
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• 2014

2-Ketogluconic acid production by Klebsiella pneumoniae is a pH-dependent process, strictly proceeding under acidic conditions. Unfortunately, cell growth is inhibited by acidic conditions, resulting in low productivity of 2-ketogluconic acid. To overcome this deficiency, a two-stage fermentation strategy was exploited in the current study. During the first stage, the culture was maintained at neutral pH, favoring cell growth. During the second stage, the culture pH was switched to acidic conditions favoring 2-ketogluconic acid accumulation. Culture parameters, including switching time, dissolved oxygen levels, pH, and temperature were optimized for the fed-batch fermentation. Characteristics of glucose dehydrogenase and gluconate dehydrogenase were revealed in vitro, and the optimal pHs of the two enzymes coincided with the optimum culture pH. Under optimum conditions, a total of 186 g/l 2-ketogluconic acid was produced at 26 h, and the conversion ratio was 0.98 mol/mol. This fermentation strategy has successfully overcome the mismatch between optimum parameters required for cell growth and 2-ketogluconic acid accumulation, and this result has the highest productivity and conversion ratio of 2-ketogluconic and produced by microorganism.

• Asian Pacific Journal of Cancer Prevention
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• 제15권1호
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• pp.199-203
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• 2014

Background: Rosuvastatine, doxazosin, repaglinide and oxcarbazepin are therapeutic drugs available in the market for the treatment of different diseases. Potential to display antitumor activities has also been suggested. The aim of the current study was to evaluate their in vitro effects on some human transformed cell lines. Materials and Methods: Cytotoxicity of the four drugs was tested in MCF-7, HeLa and HepG2 cells by the neutral red assay method and also the effect of rosuvastatine and doxazosin against Ehrlich Ascities Carcinoma Cells (EACC) by trypan blue assay. Results: Rosuvastatine exerted the greatest cytotoxic effect against HepG2 cells with an $IC_{50}$ value of $58.7{\pm}69.3$; in contrast doxazosin showed least activity with $IC_{50}=104.4{\pm}115.7$. Repaglinide inhibited the growth of both HepG2 and HeLa cells with $IC_{50}$ values of $87.6{\pm}117.5$ and $89.3{\pm}119.5$, respectively. Oxcarbazepine showed a potent cytotoxicity against both HeLa ($IC_{50}=19.4{\pm}43.9$) and MCF7 cancer cells (($IC_{50}=22{\pm}35.7$).On the other hand the growth of EACC was completely inhibited by doxazosine (100% inhibition) while rosuvastatine had weak inhibitory activity (11.6%). Conclusions: The four tested drugs may have cytotoxic effects against hepatic, breast and cervical carcinoma cells; also doxazosine may inhibit the growth of endometrial cancer cells. Further investigations in animals are needed to confirm these results.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권8호
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• pp.387-393
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• 2001

This paper describes an advanced measuring method and precise evaluation of the ground resistance for the grounding system of energized substations and power equipments. A grounding system of substations consists of all interconnected grounding connections of grounded conductors, neutral ground wires, underground conductors of distribution lines, cable shields, grounding terminals of equipments, and etc. It is very difficult to measure the accurate ground resistance of the grounding terminals of equipments, and etc. It is very difficult to measure the accurate ground resistance of the grounding system of high voltage energized substations because of harmonic components caused by switched power supplies or overloads. The conventional fall-of-potential method may be subject to big error if stray ground currents and potentials are present. In this work, to improve the precision in measurements of the ground resistance by eliminating the effects of harmonic components and stray currents and potentials, the investigations of the ground resistance measurement by using a low pass filter in a model energized grounding system were conducted. The accuracy of ground resistance mesurements was evaluated as a function of the ratio of the test signal to noise (S/N). The errors due to the proposed ground resistance measurement method were decreased with increasing S/N and were less than 5[%] as S/N is 10. The proposed ground resistance measurement method appears to be considerably more accurate than the conventional fall-of -potential method. It is allows cancellation of the parasitic resistance of energized grounding systems, to employ the measurement method that allows cancellation of the parasitic effects due to other circulating ground currents and ground potential rises in practical situations.