• 농약과학회지
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• 제7권4호
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• pp.288-295
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• 2003

유기인계 살충제인 chlorpyrifos에 대한 배추좀나방의 저항성 원인을 구명하기 위하여 저항성 인자로 알려진 두 가지 무독화 효소, esterases와 glutathione- S-trasferase(GST)의 활성과 작용점 효소인 acetylcholinesterase(AChE)의 insensitivity 정도를 측정하였다. 또한 chlorpyrifos와 작용점이 동일한 계통의 살충제에 대한 저항성 발달과의 상관관계를 조사하여 교차저항성 발달 특성을 검정하였다. 감수성 배추좀나방에 chlorpyrifos의 아치사량을 처리하여 160배의 저항성을 나타내도록 선발하여 실험에 사용하였다. 저항성 계통의 GST 활성은 감수성 계통의 GST 활성에 비하여 1.7배 높았으나, 감수성 계통과 저항성 계통간에 esterases 활성 차이는 없었다. 또한 chlorpyrifos의 작용점인 AChE insensitivity 측정결과 저항성 계통이 감수 성계통보다 11.6배 높았다. Chlorpyrifos 저항성 계통은 AChE을 저해하는 것으로 알려진 유기인계 및 카바 메이트계 살충제인 dichlorvos, dimethylvinphos, carbofuran에 대해서도 각각 33.6배, 17.6배, 18.7배의 insensitivity를 나타내었다. 그러나 동일한 작용점을 저해하는 phenthoate-oxon에 대해서는 1.7배의 낮은 insensitivity를 보였다. 또한 이들 약제들에 대한 교차저항성 발달정도를 측정한 결과, chlorpyrifos 저항성 계통은 dichlorvos, dimethylvinphos, carbofuran에 대하여도 각각 82배, 47배, 42배의 높은 교차저항성 발달을 나타내었으나, phenthoate에 대해서는 2.3배로 낮은 교차저항성 발달을 보여 작용점이 동일한 유사계열 약제들이라도 저항성을 유발하는 기작에는 서로 큰 차이가 있을 수 있음을 확인할 수 있었다. 본 실험 결과 AChE insensitivity 와 저항성 발달비 간에는 정의상관관계$(r=0.9951^{**},\;p^{(0.01)}$를 보이는 것으로 나타났는데, 이는 유기인계 및 카바메이트계 살충제의 저항성 발달이 AChE에 대한 insensitivity 정도와 관련 있음을 시사하는 것이다. 본 연구의 결과를 통하여 chlorpyrifos에 대한 배추좀나방의 저항성 발달은 작용점인 AChE에 대한 약제의 insensitivity가 주 요인 중 하나이며, 무독화 효소 중 GST 활성증가가 부가적인 요인이 될 수 있음을 확인할 수 있었다.

• 농약과학회지
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• 제10권1호
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• pp.50-55
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• 2006

본 연구는 강원도 고랭지 배추경작지에서 채집한 chlorpyrifos 포장저항성 계통의 배추좀나방에서 추출한 무독화 효소 esterases와 glutathione-S-tranferase(GST)의 활성과 단백질의 sequestration 비율 및 acetylcholinesterase(AChE) insensitivity를 측정하여 저항성 발달기작을 구명하고자 수행되었다. Esterases의 경우 저항성과 감수성 배추좀나방간의 활성 차이는 없었으나, 전기영동상에서는 특정 isozyme의 차이가 확인되었으며, GST 활성은 포장저항성 계통이 감수성 계통보다 약 1.5배 높았다. 두 계통 간 단백질의 sequestration 차이는 없었으며, chlorpyrifos에 대한 AChE의 sensitivity는 포장저항성 계통의 AChE가 감수성계통보다 약 460배 낮은 것으로 확인되었다. 이러한 결과는 실내에서 저항성을 유도하여 파악한 배추좀나방의 저항성 특성결과와 동일한 것으로 강원도 고랭지 chlorpyrifos 포장저항성 배추좀나방의 저항성 발달은 AChE의 insensitivity가 주요 요인이며, 부가적으로 GST의 활성 변화도 작용하는 것으로 판단되었다.

• 약학회지
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• 제37권4호
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• pp.350-355
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• 1993

The preparation of Streptococcus faecalis RSI is used as a medicinal preparation for human intestinal disorders. But the microbe in this preparation is very sensitive to rifampicin. If this preparation is taken with rifampicin, its therapeutic effect can not be expected. To develope rifampicin resistant mutants, the rifampicin sensitive strain S. faecalis RSI was treated with Nmethyl-N'-nitro-N-nitrosoguanidine(MNNG). Twelve strains of the MNNG-induced mutants showed distinct resistance to rifampicin and five mutants were selected for further studies. They also exhibited identical characteristics with the parent S. faecalis RSI when they were tested for lactic acid formation and growth inhibition of E. coli. From in vitro test, it was identified that rifampicin is not inactivated by certain factors of the rifampicin resistant mutants. Conclusively, the rifampicin resistant mutants are efficient strains that have insensitivity against rifampicin and original biochemical characteristics of the parent strain.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.224-224
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• 2015

Gel have enormous applicable region due to inherently high stretchability and bio-compatibility. Here, we fabricated highly stretchable electronic conductive organogels which have long-term stability in environment. By introducing a dialysis step which can incorporate conducting polymer, PEDOT, on the procedure of gel synthesis, residual ions inside the gel were removed. In addition, we replaced the water with organic solvent, EG, inside the gels which is high stability in air. Unlike conventional hydrogels, there are no ionic conduction occurred and electrochemically driven current was prevented during electrical voltage was applied. The fabricated organogels are hardly dried during air exposure, and only electrically conductive without any electrochemical reaction at even high voltage. In order to utilize as stretchable conductor, we demonstrated a LED array circuit using the conductive organogels as electrical interconnects. It was successfully operative even stretched up to 300% strain.

• 약학회지
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• 제40권3호
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• pp.351-356
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• 1996

The preparation of Enterococcus faecalis RSI is used as a therapeutics for human intestinal disorders. However, the microbe in this preparation is usually very sensitive to rifampicin and fluoroquinolones. If this preparation is taken with rifampicin or fluoroquinolones, its therapeutic effect can not be expected. E. faecalis RFR11, containing resistance to rifampicin was obtained by MNNG mutation method. Serial passage of E. faecalis RFR11 produced E. feacalis OFR16 on agar with 2-fold minimal inhibitory concentration of ofloxacin produced. E. feacalis OFR16 was resistant to fluoroquinolones up to 8-256 fold higher than that for the original strain. E. faecalis OFR16 also exhibited identical characteristics with the parent strain when they were tested for lactic acid formation and growth inhibition of E. coli MB4-5737 and Shigella sonnei MB4-10411. From in vitro test, it was identified that rifampicin and ofloxacin is not inactivated by certain factors of E. faecalis OFR16. Conclusively. E. faecalis OFR16, rifampicin and fluoroquinolones resistant mutant, is an efficient strain that has insensitivity against rifampicin and fluoroquinolones and original biochemical characteristics of the parent strain.

• Structural Engineering and Mechanics
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• 제55권4호
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• pp.857-869
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• 2015

The aluminum 7075-T6 is known as an alloy widely used in aircraft structural applications, which does not exhibit strain rate sensitivity during dynamic compressive tests. Despite mechanical importance of the material, there is not enough attention to determine appropriate sample dimensions such as a sample diameter relative to the device bar diameter and sample length to diameter (L/D) ratio for dynamic tests and how these two parameters can change mechanical behaviors of the sample under dynamic loading condition. In this study, various samples which have different diameters of 31.8, 25.4, 15.9, and 9.5 mm and sample L/D ratios of 2.0, 1.5, 1.0, 0.5, and 0.25 were tested using Split Hopkinson Pressure Bar (SHPB), as this testing device is proper to characterize mechanical behaviors of solid materials at high strain rates. The mechanical behavior of this alloy was examined under ${\sim}200-5,500s^{-1}$ dynamic strain rate. Aluminum samples of 2.0, 1.5 and 1.0 of L/D ratios were well fitted into the stress-strain curve, Madison and Green's diagram, regardless of the sample diameters. Also, the 0.5 and 0.25 L/D ratio samples having the diameter of 31.8 and 25.4 mm followed the stress-strain curve. As results, larger samples (31.8 and 25.4 mm) in diameters followed the stress-strain curve regardless of the L/D ratios, whereas the 0.5 and 0.25 L/D ratios of small diameter sample (15.9 and 9.5 mm) did not follow the stress-strain diagram but significantly deviate from the diagram. Our results indicate that the L/D ratio is important determinant in stress-strain responses under the SHPB test when the sample diameter is small relative to the test bar diameter (31.8 mm), but when sample diameter is close to the bar diameter, L/D ratio does not significantly affect the stress-strain responses. This suggests that the areal mismatch (non-contact area of the testing bar) between the sample and the bar can misrepresent mechanical behaviors of the aluminum 7075-T6 at the dynamic loading condition.

• 한국재료학회지
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• 제21권3호
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• pp.161-167
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• 2011

The stress-strain responses and oxidation properties of cold-rolled Zr-1.5Nb-O and Zr-1.5Nb-O-S alloys were studied. The U.T.S. (ultimate tensile strength) of cold-rolled Zr-1.5Nb-O-S alloy with 160 ppm sulfur (765 MPa) were greater than that of Zr-1Nb-1Sn-0.1Fe alloy (750 MPa), achieving an excellent mechanical strength even after the elimination of Sn, an effective solution strengthening element. The addition of sulfur increased the strength at the expense of ductility. However, the ductile fracture behavior was observed both in Zr-Nb-O and Zr-Nb-O-S alloys. The beneficial effect of sulphur on the strengthening was observed in the cold rolled Zr-1.5Nb-O-S alloys. The activation volume of cold-rolled Zr-1.5Nb decreased with sulfur content in the temperature region of dynamic strain aging associated with oxygen atoms. Insensitivity of the activation volume to the dislocation density and the decrease of the activation volume at a higher temperature where the dynamic strain aging occurs support the suggestion linking the activation volume with the activated bulge of dislocations limited by segregation of oxygen and sulfur atoms. The addition of sulfur was also found to improve the oxidation resistance of Zr-Nb-O alloys.

• 생명과학회지
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• 제21권9호
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• pp.1295-1300
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• 2011

식물체에서 당 조절 인자의 병 저항성 생리적 특성을 살펴보길 위하여, 원형질막에 존재하는 glucose 조절인자인 애기장대 AtPGR 유전자의 과발현 및 RNAi 형질전환체를 사용하였다[3]. AtPGR 유전자는 병원균 처리에 의하여 전사 발현양이 증가하였을 뿐만 아니라, JA와 SA 처리 시에도 AtPGR 전사 발현양이 증가함을 확인하였다. 과발현 형질전환체를 이용하여 병 저항성을 살펴본 결과, AtPGR 유전자는 병원균에 대해 저항성을 유도함을 알수 있었다. 또한 병원균 유도 증가 유전자로 알려진 PDF1.2 및 PR1 유전자 발현 양상을 qPCR을 통해 살펴본 결과, AtPGR 유전자는 PDF1.2 유전자를 SA 경로 하에서는 증가시키는 반면, JA 경로 하에서는 발현 증가량을 감소시키는 경향이 있음을 나타내었고, PR1 유전자의 발현은 JA 경로를 통해 조절할 것으로 생각되어진다. 이러한 결과를 바탕으로, AtPGR 유전자는 glucose 뿐만 아니라 병원균 반응에도 관련되어져 있음을 알 수 있다.