• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.249-257
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• 2002

Pseudomonas fluorescens GL20 is a plant growth-promoting rhizobacterium that produces a large amount of hydroxamate siderophore under iron-limited conditions. The strain GL20 considerably inhibited the spore germination and hyphal growth of a plant pathogenic fungus, Fusarium solani, when iron was limited, significantly suppressed the root-rot disease on beans caused by F. solani, and enhanced the plant growth. The mechanism for the beneficial effect of strain GL20 on the disease suppression was due to the siderophore production, evidenced by mutant strains derived from the strain. Analysis of the outer membrane protein profile revealed that the growth of strain GL20 induced the synthesis of specific iron-regulated outer membrane proteins with molecular masses of 85- and 90 kDa as the high-affinity receptors for the ferric siderophore. In addition, a cross-feeding assay revealed the presence of multiple inducible receptors for heterologous siderophores in the strain. In order to induce increased efficacy and potential in biological control of plant disease, a siderophore-overproducing mutant, GL20-S207, was prepared by NTG mutagenesis. The mutant GL20-S207 produced nearly 2.3 times more siderophore than the parent strain. In pot trials of beans with F. solani, the mutant increased plant growth up to 1.5 times compared with that of the parent strain. These results suggest that the plant growth-promoting P. fluorescens GL20 and the genetically bred P. fluorescens GL20-S207 can play an important role in the biological control of soil-borne plant diseases in the rhizosphere.

• Geomechanics and Engineering
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• 제17권6호
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• pp.507-513
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• 2019

Reinforced soil and Expanded Polystyrenes (EPS) mixture (RSEM) is a geomaterial which has many merits, such as light weight, wide strength range, easy for construction, and economic feasibility. It has been widely applied to improve soft ground, solve bridge head jump, fill cavity in pipeline and widen highway. Reutilizing dredged sediment to produce RSEM as earthfill can not only consume a large amount of waste sediment but also significantly reduce the construction cost. Therefore, there is an urgent need understand the basic stress-strain characteristics of reinforced dredged sediment-EPS mixture (RDSEM). A series of cyclic triaxial tests were then carried out on the RDSEM and control clay. The effects of cement content, EPS beads content and confining pressure on the cyclic stress-strain behaviour of RDSEM were analyzed. It is found that the three stages of dynamic stress-strain relationship of ordinary soil, vibration compaction stage, vibration shear stage and vibration failure stage are also applicative for RDSEM. The cyclic stress-strain curves of RDSEM are lower than that of control clay in the vibration compaction stage because of its high moisture content. The slopes of backbone curves of RDSEMs in the vibration shear stage are larger than that of control clay, indicating that the existence of EPS beads provides plastic resistance. With the increase of cement content, the cyclic stress-strain relationship tends to be steeper. Increasing cement content and confining pressure could improve the cyclic strength and cyclic stiffness of RDSEM.

• 지질공학
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• 제23권4호
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• pp.353-361
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• 2013

본 연구에서는 ${\bigcirc}{\bigcirc}$지역 토목용 계측기에서 측정된 지진유발 변형률 데이터의 분포 특성을 분석하기 위한 기법으로 응용통계기법에 대한 적용성을 평가하였다. 2011년 도호쿠 대지진과 같은 해에 발생한 규모 7.0 이상의 여진을 계측한 4방향의 변형률 데이터를 활용하였다. 데이터의 미세한 변동을 감지하기 위하여 단변량 분석기법인 x-MR 분석을 실시하였으며 분석결과 계측 데이터 간의 분산시점에 차이가 발생하는 것을 확인하였다. 이러한 분산시점의 차이를 해결하기 위하여 변형률 데이터 간의 상관성을 고려한 다변량 통계분석을 실시하였다. 다변량 분석기법 가운데 하나인 주성분 분석결과를 $T_2$과 Q-통계량 분석에 적용하여 신뢰구간 99.9%, 99.0%, 95.0%로 실시간 분석을 수행하였다. 분석결과 $T_2$과 Q-통계량 값이 신뢰구간 99.9%를 초과하는 시점은 x-MR 분석의 분산시점과 일치하거나 이른 시간으로 나타났다. 또한, 신뢰구간 95.0%와 99.0%를 초과하는 시점은 99.9%를 초과하는 시점 이전에 타점되어 지진발생 전에 이상 분포 발생을 예측할 수 있었다. 이러한 결과는 변형률 데이터의 비정상적인 분포 특성을 다변량 통계분석법으로 인지할 수 있다는 것을 의미한다. 따라서 다변량 통계분석은 변형률 데이터의 분포 특성을 분석하여 지진을 예지하는 방법으로 이용가능하다고 판단된다.

• The Journal of Korean Physical Therapy
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• 제10권2호
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• pp.113-125
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• 1998

The neurotropic psudorabies virus(PRV) to replicate within neurons is very useful pathogen for neuronal tracing. I carried out this study to investigate the parametric analysis on the viral infection in the rat circadian control center with two genetically engineered strains out of PRV. The two strains are isogenic with the attenuated Bartha strain of PRV ; in one strain a lacZ reporter gene was inserted into the gC locus (PRV-BaBlu ; $4.75\times10^8pfu/ml$) and the other strain contained a PRV envelope glycoprotein gene(PRV-D ; $2.5\times10^8pfu/ml$) theat is absent in PRV-BaBlu. simultaneous or temporally separated sequential injection of$2{\mu}l$ of each strain into the vetreous body of eye produced a course of transsynaptic infection of retinohypothalamic circuitry. The results were as follows; 1. PRV-BaBlu and PRV-D infected the suprachiasmatic nucleus in hypothalamus and intergeniculate leaflet in lateral geniculate nucleus of thalamus. 2. The rate of PRV infection was dependent upon PRV strain. 3. Pre-infected neurons by PRV-D were interfered with the replication of PRV-BaBlu. 4. Dual injection of PRV-D and PRV-BaBlu showed more virulent than the parental strain.

• Journal of Animal Science and Technology
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• 제63권3호
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• pp.662-665
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• 2021

Streptococcus suis is a major pig pathogen causing severe economic losses to the swine industry. This study aimed to analyze the genome of S. suis strain INT-01 isolated from a domestic pig in Korea. We found that the genome of strain INT-01 contains 2,092,054 bp, with a guanine (G) + cytosine (C) content of 41.3%, and the capsular polysaccharide synthesis locus of this strain is almost identical to that of serotype 3 S. suis strain 4961 isolated from China, suggesting that these isolates can be classified as serotype 3. Genomic analyses revealed that strain INT-01 is an extracellular protein factor (epf)^-/ muraminidase-released protein (mrp)⁺/ suilysin (sly)^- S. suis, which is the most prevalent genotype in Korea, and several virulence-related genes associated with the pathogenicity of S. suis were also detected. The genomic information of strain INT-01 may provide important insights into the development of control strategies against S. suis infections in Korea.

• 한국산림과학회지
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• 제96권1호
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• pp.1-6
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• 2007

홍가슴루리잎벌(Arge captiva)과 장미등애잎벌(A. pagana pagana), 극동등애잎벌(A. similis)의 환경친화적 방제를 위하여 곤충병원성 선충(Heterorhabditis sp. 경산 계통, Steinernema carpocapsae GSN1 계통, S. feltiae Monteri 계통, S. glaseri 동래 계통, S. longicaudum 논산 계통, S. monticolum 지리 계통)을 이용하여 실내와 포트에서 실험을 수행하였다. 홍가슴루리잎벌 3령충에 대한 곤충병원성 선충의 병원성은 S. carpocapsae GSN1 계통과 S. feltiae Monteri 계통 처리 시, 처리 5일 후 100%의 치사율을 보였다. 홍가슴루리잎벌레 3령충에 침입한 선충의 수는 S. glaseri 동래 계통의 경우 10.2마리였으며 S. carpocapsae GSN1 계통은 4.2마리였다. 장미등애잎벌의 령기별에 따른 S. carpocapsae GSN1 계통의 병원성은 노숙화 될수록 높아 2령충과 3령충, 4령충에 대한 반수치사농도($LC_{50}$)는 각각 11.5, 9.3, 8.4 마리였다. Pot 실험에서 S. carpocapsae GSN1 계통을 $2{\times}10^9$마리/ha 농도로 처리 시, 홍가슴루리잎벌과 장미등애잎벌, 극동등애잎벌의 보정사충율은 각각 72.5, 85.0, 85.0%를 나타내었다.

• Smart Structures and Systems
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• 제3권2호
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• pp.147-172
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• 2007

The present paper is concerned with the design of distributed sensors and actuators. Strain type sensors and actuators are considered with their intensity continuously distributed throughout a continuous structure. The sensors measure a weighted average of the strain tensor. As a starting point for their design we introduce the concept of collocated sensors and actuators as well as the so-called natural output. Then we utilize the principle of virtual work for an auxiliary quasi-static problem to assign a mechanical interpretation to the natural output of the sensors to be designed. Therefore, we take the virtual displacements in the principle of virtual work as that part of the displacement in the original problem, which characterizes the deviation from a desired one. We introduce different kinds of distributed sensors, each of them with a mechanical interpretation other than a weighted average of the strain tensor. Additionally, we assign a mechanical interpretation to the collocated actuators as well; for that purpose we use an extended body force analogy. The sensors and actuators are applied to solve the displacement tracking problem for continuous structures; i.e., the problem of enforcing a desired displacement field. We discuss feed forward and feed back control. In the case of feed back control we show that a PD controller can stabilize the continuous system. Finally, a numerical example is presented. A desired deflection of a clamped-clamped beam is tracked by means of feed forward control, feed back control and a combination of the two.

• 센서학회지
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• 제27권6호
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• pp.392-396
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• 2018

Structural color has many advantages over pigment based color. In recent years, researches are being conducted to apply these advantages to applications such as wearable devices. In this study, strain sensor, a kind of wearable device, was developed using structural color. The use of structural color has the advantage of not using energy and complex measuring equipment to measure strain rate. Wrinkle structure was fabricated on the surface of Poly-dimethylsiloxane (PDMS) and used it as a sensor which color changes according to the applied strain. In addition, a transmittance-changing sensor was developed and fabricated by synthesizing additional glass nanoparticles. Furthermore, a strain sensor was developed that is largely transparent at the target strain and opaque otherwise.

• International Journal of Oral Biology
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• 제46권4호
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• pp.155-159
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• 2021

This study aimed to develop strain-specific polymerase chain reaction (PCR) primers to detect Fusobacterium hwasookii KCOM 1249^T, F. hwasookii KCOM 1253, F. hwasookii KCOM 1256, F. hwasookii KCOM 1258, and F. hwasookii KCOM 1268 on the basis of nucleotide sequences of a gene specific to each strain. The unique genes for each F. hwasookii strain were determined on the basis of their genome sequences using Roary. The strain-specific PCR primers based on each strain-specific gene were designed using PrimerSelect. The specificity of each PCR primer was determined using the genomic DNA of the 5 F. hwasookii strains and 25 strains of oral bacterial species. The detection limit and sensitivity of each strain-specific PCR primer pair were determined using the genomic DNA of each target strain. The results showed that the strain-specific PCR primers correspond to F. hwasookii KCOM 1249^T, F. hwasookii KCOM 1253, F. hwasookii KCOM 1258, F. hwasookii KCOM 1256/F. nucleatum subsp. polymorphum KCOM 1260, or F. hwasookii KCOM 1268/Fusobacterium sp. oral taxon 203 were developed. The detection limits of these strain-specific PCR primers ranged from 0.2 to 2 ng of genomic DNA for each target strain. The results suggest that these strain-specific PCR primers are valuable in quality control for detecting specific F. hwasookii strains.

• 한국식품위생안전성학회지
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• 제39권1호
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• pp.1-8
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• 2024

Salmonella spp. 11 strains에 대해 저온 열처리(50℃) 3, 6, 9분 후 MIC값을 측정하여 항생제 내성을 알아보았다. Chloramphenicol에 대해 대조군과 열처리한 strains 대부분에서 감수성(S)이 있는 것으로 나타났고, 열처리한 strains의 MIC값은 대조군과 비교하였을 때 유지되거나 감소하였다. Ciprofloxacin에 대해 대조군과 열처리한 strains는 대부분 감수성(S)이 있거나 중간(I)을 나타냈다. Tetracycline은 모든 strains에서 감수성(S)이 있는 것으로 나타났으며, S. Gaminara BAA 711에 대해 열처리 후 MIC값이 증가하였다. Gentamicin에 대해 대조군 strains들에서 감수성을 나타낸 strains가 3 strains, 중간을 나타낸 strains 2 strains, 내성을 가진 strains가 6 strains였으며, 이 중 S. Heidelberg ATCC 8326는 MIC값을 측정했을 때 대조군에서 MIC값이 8 ㎍/mL로 MIC break point가 중간이었으나, 3분과 9분 열처리 후 MIC값이 16 ㎍/mL로 증가하여 break point가 내성을 나타냈다. 본 실험결과 Salmonella spp. 11 strains에 대해서 저온 열처리 후 열내성 효과에 의한 항생제 내성을 알아봤을 때 ciprofloxacin에서 S. Montevideo BAA 710을 3, 6분 열처리한 경우, gentamicin에서 S. Enteritidis 109 D1을 3분 처리한 경우와 S. Heidelberg ATCC 8326을 3, 9분 처리한 경우, tetracycline에서 S. Gaminara BAA 711을 6, 9분 처리한 경우 MIC값이 증가하였다. 후속 연구를 통해 Salmonella spp. strains에 대해 열처리 후 열내성 효과를 나타내는 병원성 유전자의 특성에 대한 지속적인 연구가 필요하다.