• Journal of Microbiology
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• 제39권1호
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• pp.62-66
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• 2001

Unlike eukaryotic efflux pumps energized by ATPase bacterial efflux pumps are energized by the proton motive force. That is the reason why CCCP, an inhibitor of proton motive forcer is widely used to study the bacterial efflux pump. In many cases, efflux systems have been observed only in quinolone-resistant bacteria. Most of the quinolone-susceptible strains have been found to maintain little efflux pump. However some susceptible bacteria skewed the increased intracellular quinolone concentration only at a low concentration (0.01 or 0.1 mM) but net at a high concentration (1 mM) of CCCP. If bacterial cells were killed at high concentrations of CCCP and lost the integrity of their membranes, the intracellular quinolone would leak out from cells with no efflux system. The efflux pump system in the quinolone-susceptible strains could net be detected at the same concentration used for resistant bacteria. To test this hypothesist the intracellular quinolone concentration in the quinolone-susceptible and -resistant strains of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus was assayed at various concentrations of CCCP. Since the effect of CCCP is very rapid, the survival of bacteria was observed by assaying the DNA synthesis in 5 min. In the case of E. coli, but not P. aeruginosa or S. aureus, the quinolone susceptible strain was more susceptible to CCCP than the quinolone resistant ones, especially when the incubation with CCCP was extended. Decrease of the intracellular quinolone concentration resulted in a false result-no or weak efflux system in the quinolone susceptible strains. Results suggested that the concentration of CCCP should be optimized in order to detect the efflux system in the quinolone susceptible strains of E. coli.

• The Plant Pathology Journal
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• 제31권2호
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• pp.132-139
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• 2015

Bt-cotton germplasm, consisting of 75 genotypes was evaluated against cotton leaf curl disease (CLCuD) under high inoculum pressure in the field and using graft inoculation in glasshouse by visual symptom scoring assessments. None of the tested genotype was found disease free under both evaluation tests. Under field conditions in 2011, 3 genotypes were found resistant, 4 moderately resistant, 3 tolerant, 2 moderately susceptible and one susceptible; in 2012, 3 genotypes were tolerant, 7 moderately susceptible, 5 susceptible and 38 highly susceptible; in 2013, one was moderately susceptible and 51 were highly susceptible with varying degree of percent disease index (PDI) and severity index (SI). However, through graft evaluation in glasshouse, none of the graft inoculated plant was symptomless. All tested genotypes showed disease symptoms with SI values ranging between 5.0 and 6.0, and latent period between 12 and 14 days. Of the 75 genotypes evaluated using graft inoculation, 11 were found susceptible with SI values of 5.0 to 5.4 while remaining 64 were highly susceptible with SI values of 5.5 to 6.0. Inoculated plants of all tested genotypes exhibited severe disease symptoms within 10 days after the appearance of initial symptoms. No reduction in SI value was observed until the end of the experiment i.e., 90 days after grafting. Information generated under the present study clearly demonstrates that no sources of resistance to CLCuD are available among the tested Bt-cotton genotypes. So, a breeding programme is needed to introgress the CLCuD-resistance from other resistant sources to agronomically suitable Bt-cotton genotypes.

• Geomechanics and Engineering
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• 제30권4호
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• pp.393-399
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• 2022

The Segregation Potential (SP) is one of the most widely used predictors of frost heave in cold regions. Laboratory step-freezing tests determining a representative SP at the onset of the formation of the last ice lens (near the thermal steady state condition) can predict susceptibility to frost heave. Previous work has proposed empirical semi-log fitting for determination of the representative SP and applied it to several fine-grained soils, but considering only frost-susceptible soils. The presence of fines in coarse-grained soil affects frost susceptibility. Therefore, it is required to evaluate the applicability of the empirical semi-log fitting for both frost-susceptible and non-frost-susceptible soils with fines content. This paper reports laboratory frost heave tests for fines contents of 5%-70%. The frost susceptibility of soil mixtures composed of sand and silt was classified by the representative SP, and the suitability of the empirical semi-log fitting method was assessed. Combining semi-log fitting with simple laboratory frost heave testing using a temperature-controllable cell is shown to be suitable for both frost-susceptible and non-frost-susceptible soils. In addition, initially non-frost-susceptible soil became frost susceptible at a 10%-20% weight fraction of fines. This threshold fines content matched well with transitions in the engineering characteristics of both the unfrozen and frozen soil mixtures.

• 한국응용곤충학회지
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• 제16권4호
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• pp.193-197
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• 1977

Pythium ultimum에 의한 묘립고병에 감수성인 완두품종의 종자는 저항성품종의 종자보다 다량의 환원당이 종자분필물내에 포함되었으며 분필속도도 감수성인 완두품종의 종자에서 더 빨랐다. 묘립고병에 저항성인 완두품종의 종자와 감수성인 품종의 종자분필물에서 모두 Raffinose, Meilbiose, Sucrose, Glucose 및 Fructose가 확인되었으나 Glucose와 Sucrose는 감수성 품종의 종자분필물에서 더 많이 검출되었다. Pythium ultimum균은 감수성인 종자 및 종자분필물에서 더 잘 자랐다.

• 아동학회지
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• 제25권4호
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• pp.17-32
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• 2004

Factor analysis of data collected from 336 elementary school children provided difficuitness and susceptibility as the temperament factors, and affect and control as the nurturing factors. Results showed that non-susceptible children with low controlling mother perceived their cognitive competence positively while highly susceptible children showed no differences in their self-competence by mothers' controlling behavior. Perceived cognitive competence of susceptible boys and of susceptible 3rd graders were low when their mothers asserted low control. Thus, mothers' controlling behavior supported perceived cognitive competence in highly susceptible boys and 3rd graders. That is, the effect of mother's behavior on child's self-competence was moderated by child's characteristics. These results partially supported the Conditional Model.

• 대한미생물학회지
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• 제9권1호
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• pp.19-24
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• 1974

During March to October 1973 at National Medical Center, one thousand four hundred sixty four pathogens that exclude penicillin sensitive organisms such as gonococcus, pneumococcus, streptococcus; ampicillin sensitive H. influenzae and gentamicin sensitive pseudomonas spp, were isolated. These strains identified as follows: Sta. aureus 399 E. coli 359 Sta. epidermidis 183 Klebsiella spp 171 Proteus spp 103 B. anitratum 80 Salmonella spp 68 Enterococcus 53 Shigella spp 48 In general, Sta. epidermidis is regarded as nonpathogen, however, author included pure culture of this bacteria in this study. 1. High susceptibility to staphylococcus reveals cephalosporin, methicillin, gentamicin & leucomycin. 2. Ampicillin is only one susceptible antibiotic to Enterococcus. 3. Cephalosporin and gentamicin reveal susceptible antibiotics to E. coli. 4. Gentamicin is only one susceptible antibiotic to Klebsiella spp. 5. Gentamicin & carbenicillin reveal moderately susceptible antibiotics to Proteus spp. 6. There is no susceptible antibiotic to B. anitratum. 7. About thirty percent strains of salmonella are resistant to chloramphenicol. 8. Carbenicillin, cephalosporin & gentamicin reveal susceptible to shigella spp. 9. Multiple resistant rate to more than two antibiotics which includes tetracycline are as follows. Sta. aureus 56.5% E. coli. 80.9% Shigella spp 93.8%

• 한국유체기계학회 논문집
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• 제10권5호
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• pp.20-26
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• 2007

Some gate valves are susceptible to pressure locking and thermal binding which prevent the safety function. The safety related gate valves susceptible to pressure locking and thermal binding shall be identified and taken preventive actions to ensure the safety function. The identification of the gate valves susceptible to pressure locking and thermal binding needs the evaluation of system design, valve and piping arrangement, test requirements, and operating conditions. Application of preventive methods should consider the system safety function, applicability, effectiveness, interface with system design, and cost. The selection procedure of valves susceptible to pressure locking and thermal binding can be effectively used in industry including nuclear power plants. In order to prevent the pressure locking, the hole can be drilled through the one disc of upstream side or down stream and the external equalizing line can be installed from bonnet to downstream or upstream. The double disc parallel seat valve type can be used instead of flexible wedge gate valve to prevent the thermal binding. The identification of gate valves susceptible to pressure locking and thermal binding, and preventive actions will meet the regulatory requirements and enhance the availability and safety of plants.

• Journal of Microbiology
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• 제40권2호
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• pp.98-103
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• 2002

Twenty-eight clinical isolates of Escherichia coil, composed of thirteen norfloxacin resistant isolates (MIC of >16${\mu}$g/ml), one intermediately resistant isolate (MIC of 8${\mu}$g/ml), and fourteen susceptible isolates (MIC of <4${\mu}$g/ml), were randomly selected to study the norfloxacin resistance mechanism and phylogeny in clinical isolates in Korea. Eleven nofloxacin resistant isolates and one susceptible isolate were multi-drug resistant (MDR). Every norfloxacin resistant isolate with MIC higher than 32${\mu}$g/ml had the same three mutations: Ser83\longrightarrowLeu and Asp87\longrightarrowAsn or Tyr in GyrA and Ser80\longrightarrowIle in ParC. Whereas a resistant isolate with MIC of 16${\mu}$g/ml had three mutations but Asp87 in GyrA was replaced with Gly instead of Asn. The intermediately resistant isolate had the same two mutations in GyrA but a different mutation in ParC, Glu84\longrightarrowLys. Among the susceptible isolates, two isolates with MIC of 4${\mu}$g/ml had one mutation: Ser83\longrightarrowiLeu in GyrA, and no mutation was found in the susceptible isolates. Resistant isolates showed higher efflux activity than the susceptible ones, with random amplification of polymorphic DNA (RAPD), six susceptible isolates form a separate group from the rest of the isolates.

• 한국잡초학회지
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• 제16권4호
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• pp.327-336
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• 1996

DPE계 제초제(除草劑)인 oxyfluorfen의 생리활성(生理活性)을 내성(耐性)으로 선발되었던 벼 3품종(品種)과 감수성(感受性) 벼 4품종(品種)및 피를 공시하여 oxyfluorfen을 처리 후 항산화제(抗酸化劑) 함량과 GST 활성(活性)으로 조사하였다. 1. 식물자체가 보유하는 vitamin C 함량은 내성(耐性) 벼품종(品種)들이 감수성(感受性) 벼품종(品種)들이나 피보다 많았다. Vitamin E, carotenoid 및 glutathione(GSH, GSSG, total glutathione) 함량은 내성(耐性)과 감수성(感受性)식물들간에 양적인 차이를 볼 수 없었다. 2. Oxyfluorfen 처리에 따른 vitamin C 함량은 내성(耐性) 벼품종(品種) Hawon과 Baru에서 감수성(感受性) 벼품종(品種)들과 피보다 감소가 적었다. Oxyfluorfen 처리후 vitamin E 및 GSH 함량은 내성(耐性) 벼품종(品種)들이 감수성(感受性) 벼품종(品種)들이나 피보다 높았다. 그러나 carotenoid 함량은 내성(耐性) 벼품종(品種)들이 감수성(感受性) 벼품종(品種)들보다 높았으나, 감수성(感受性)인 피와는 차이가 없었다. 그리고 GSSG 함량은 내성(耐性)과 감수성종(感受性種)들간 차이가 없었다. 3. CDNB 또는 oxyfluorfen을 기질로 사용했을 때 식물 자체가 보유한 GST 활성(活性)은 내성(耐性) 벼품종(品種)들이 감수성(感受性) 벼품종(品種)들이나 피보다 높았다. 4. Oxyfluorfen 처리후 GST 활성(活性)은 벼에서 유도되지 않았으나, 오히려 피에서는 유도되었다. 또한, 벼의 GST 활성(活性)은 acifluorfen, bifenox 및 oxadiazon 처리에서도 유도되지 않았다.

• 한국잡초학회지
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• 제16권1호
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• pp.54-63
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• 1996

Oxyfluorfen 내성(耐性) 및 감수성(感受性) 벼품종(品種)들과 감수성(感受性)인 피에 대하여 oxyfluorfen 처리에 따른 잎 표면구조(表面構造) 및 해부(解剖) 특성(特性)과 미세구조(微細構造) 반응(反應)을 관찰하였으며, 유이제초제(類似除草劑)에 대한 해부학적(解剖學的) 변화를 비교 관찰하였다. 1. 내성(耐性) 벼품종(品種)들은 oxyfluorfen 처리에 따른 잎 면적(表面)의 구조적(構造的)인 피해를 볼 수 없었으나, 감수성(感受性)인 벼품종(品種)은 납질(蠟質)의 손상이 크고, 감수성(感受性)인 피는 조직이 불규칙하게 붕괴되는 현상까지도 관찰할 수 있었다. 또한 감수성(感受性) 벼품종(品種)들과 피에서는 엽신(葉身)의 두께 감소도 컸다. 2. 내성(耐性) 벼품종(品種)들은 oxyfluorfen 처리에 따른 해부학적(解剖學的)인 변화가 적었으나, 감수성(感受性) 벼품종(品種)들과 피에서는 표피세포(表皮細包), 엽육세포(葉肉細包) 및 유관속초세포의 파괴가 컸으며 특히, 처리 후 24시간의 감수성(感受性) 벼품종(品種)에서는 조직이 완전히 붕괴되었다. 3. Oxyfluorfen 처리에 의해 chloroplast 모양의 불규칙성과 chloroplast envelope의 distortion이 전반적으로 관찰되었고, 전분(澱粉)도 감소되는 경향이었으며 이와 같은 구조적(構造的) 손상은 내성(耐性) 벼품종(品種)보다는 감수성(感受性)인 벼품종(品種)과 피에서 더 심했다. 4. Oxyfluorfen과 유사한 제초제(除草劑) 처리에 의하여서도 엽신(葉身)의 두께 감소는 oxyfluorfen > acifluorfen > bifenox > oxadiazon 순으로 크게 나타났으며, 내성(耐性) 벼품종(品種)보다 감수성(感受性) 벼품종(品種)에서 더 커지는 경향이었다. 특히 감수성(感受性) 벼품종(品種)은 oxyfluorfen과 bifenox 처리 후 24시간에 이미 표피세포(表皮細包) 및 유관속초세포 손실 등으로 조직이 상하게 붕괴되는 현상을 보였다.