• 한국해양바이오학회지
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• 제12권1호
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• pp.50-58
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• 2020

Sphacelaria is a filamentous brown algal genus that can be epibiotic on macroalgae, marine plants, and sea turtles. Its important role in benthic ecosystems, exposure to different stressors (e.g., grazing), and use as a model organism make Sphacelaria ideal for assessing physiological responses of organisms to environmental inputs. Single-cell RNA sequencing is a powerful new probe for understanding environmental responses of organisms at the molecular (transcriptome) level, capable of delineating gene regulation in different cell types. In the case of plants, this technique requires protoplasts ("naked" plant cells). The existing protoplast isolation protocols for Sphacelaria use non-commercial enzymes and are low-yielding. This study is the first to report the production of protoplasts from Sphacelaria fusca (Hudson) S.F. Gray, using a combination of commercial enzymes, chelation, and osmolarity treatment. A simple combination of commercial enzymes (cellulase Onozuka RS, alginate lyase, and driselase) with chelation pretreatment and an increased osmolarity (2512 mOsm/L H₂O) gave a protoplast yield of 15.08 ± 5.31 × 10⁴ protoplasts/g fresh weight, with all the Sphacelaria cell types represented. Driselase had no crucial effect on the protoplast isolation. However, the increased osmolarity had a highly significant and positive effect on the protoplast isolation, and chelation pretreatment was essential for optimal protoplast yield. The protocol represents a significant step forward for studies on Sphacelaria by efficiently generating protoplasts suitable for cellular studies, including single-cell RNA sequencing and expression profiling.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.97-102
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• 2007

As environmental vibration requirements on precision equipments get more stringent, use of pneumatic vibration isolators becomes more crucial and, hence, their dynamic performance needs to be further improved. Dynamic behavior of those pneumatic vibration isolation tables is very important to both manufacturer and customer as performance specifications. Together with conventional transmissibility, transient response characteristics are another critical performance index especially when movements of components, e.g., x-y tables, of the precision equipments are very dynamic. In this paper, analysis on transient response of a pneumatic vibration isolation table loaded by a mass moving on it is presented. This is a conventional dynamics problem on a rigid body with 6 degree of freedom and a mass with another degree of freedom. How to obtain transient responses of the isolation table is described when the movements of the mass are prescribed relative to the table.

• 한국환경복원기술학회지
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• 제13권5호
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• pp.146-153
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• 2010

Urban development typically results in many species being confined to small, isolated and degraded habitat fragments. Fragment size and isolation underpin many studies of modified landscape to prevent biodiversity loss. However, habitat characteristics such as vegetation structure and edge effects are less frequently incorporated in planning. The relative influence of biogeographic (e.g. size, isolation) and vegetation parameters on assemblages is poorly understood, but critical for conservation management. In this study, the relative importance of biogeographic and vegetation parameters in explaining the diversity of forest-interior dwelling birds in forest fragments in Chungcheong Province Area. Fragment size and vegetation characteristics were consistently important predictors of bird diversity. Forestinterior bird richness was influenced by fragment size (0.437), wood age (0.332), wood diameter (0.068), and patch shape (-0.079). To preserve bird diversity of Chungcheong Province Area, it is important to consider differing responses of bird diversity to landscape change, move beyond a focus primarily on spatial attributes (size, isolation) to recognize that landscape change also has profound effects on habitat composition and quality. The result is very useful for long-term aspect of biodiversity conservation plan in regional scale.

• 한국소음진동공학회논문집
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• 제17권6호
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• pp.515-523
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• 2007

As environmental vibration requirements on precision equipments get more stringent, use of pneumatic vibration isolators becomes more crucial and, hence, their dynamic performance needs to be further improved. Dynamic behavior of those pneumatic vibration Isolation tables is very important to both manufacturer and customer as performance specifications. Together with conventional transmissibility, transient response characteristics are another critical performance index especially when movements of components, e.g., x-y tables, of the precision equipments are very dynamic. In this paper, analysis on transient response of a pneumatic vibration isolation table loaded by a mass moving on it is presented. This is a conventional dynamics problem on a rigid body with 6 degree of freedom and a mass with another degree of freedom. How to obtain transient responses of the isolation table is described when the movements of the mass are prescribed relative to the table.

• 미생물학회지
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• 제49권2호
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• pp.179-183
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• 2013

해양에서 유래된 미생물들은 지금까지 다양한 대사체들을 생산해 왔다. 해양 미생물로부터 대사체를 규명해 내고자 하는 연구의 일환으로, Aspergillus protuberus가 선택되었다. 이 균주를 대량 배양하여 배양물을 유기용매로 추출한 후, 추출물을 실리카 겔 칼럼 크로마토그라피로 분획하였다. 그 후 분획물에 분취용 HPLC 등을 실시하여 총 3종의 대사체들을 분리하였다. 분리된 대사체들의 화학적 구조는 NMR, MS, UV 등의 기기분석 방법을 이용하여 각각 deoxybrevianamide E (1), brevianamide V (2) 및 ergosterol peroxide (3)로 동정하였다. 이 A. protuburutus가 생산해 내는 대사체에 관한 연구는 본 연구에서 처음으로 이루어졌다.

• 대한수의학회지
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• 제36권2호
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• pp.371-378
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• 1996

Three and 2 strains of E coli O157 were isolated from fecal materials of cattle (390) and pigs (420) in Korea, respectively. One strain of O157:H7 isolated from cattle and 2 strains of O157:H7 isolated from pigs were identified as verotoxin-1 (VT-1) produing strains and 2 strains (O157:H7 and O157:H-) isolated from cattle were identified as verotoxin-2 (VT-2) producing strains by neutralization test on HeLa and Vero cells. Culture supernatants of the isolates were cytotoxic to HeLa and Vero cells. The levels of cytotoxin produced by isolates were $10^2{\sim}10^4$ cytotoxic dose($CD_{50}$)/ml. Also, VT-2-converting bacteriophage was isolated from KSC109 strain which had been isolated from cattle. Molecular weight of the phage DNA was determined as approximately 45 Kb in 0.8% agarose gel electrophoresis, and morphology of the phage stained with phosphotungstic acid was observed by transmissible electron microscopy.

• 생명과학회지
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• 제8권6호
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• pp.711-722
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• 1998

본 연구는 혈액에서 분리되는 세균의 항균제 감수성 양상을 파악하기 위하여 1993년 10월 1일부터 1996년 9월 30일 사이에 K대학 부속병원의 입원 및 외래환자 13,595명을 대상으로 혈액배양에서 분리된 1,104균주중 716균주를 세균의 균종별, 연령별, 계절별 분리빈도와 항균제 감수성 검사를 실시하여 다음과 같은 결과를 얻었다. 1. 최근 3년간 균분리 양성은 1,104명으로 8.1%의 양성률을 보였다. 연구대상 716균주의 균종별 분리빈도는 E. coli가 29.8% (213주)로 분리율이 가장 높았다. 2. 대부분의 균종은 50세, 60세군 및 2세 이하군에서 분리율이 높았고, S. typhi는 30세군에서 분리율이 높았다. 3. 계절별 분리율은 대부분의 균종이 여름철에 분리율이 높았고, E. coli는 계절에 관계없이 분리되었다. 4. 항균제 감수성은 그람양성 구균의 경우 penicillin계 항균제인penicillin-G에 E. faecalis를 제외한 균에서 높은 내성률을 보였으며, vancomycin과 teicoplanin에는 감수성이 높았다. 그람음성 간균은 amikacin, ciprofloxacin, 및 imipenem에는 감수성이 높았고, ampicillin에는 내성을 보였다. S. typhi는 cephalothin을 제외한 모든 항균제에 100%의 감수성이었다. 이상의 결과에서 균혈증 환자로부터 분리된 세균에는 penicillin계 항균제에 내성인 균주가 많으며 glycopeptide계 항균제와 amikacin, ciprofloxacin 및 imipenem에는 아직 내성이 낮다는 결론을 얻었다.

• Smart Structures and Systems
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• 제25권3호
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• pp.323-335
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• 2020

Magnetorheological elastomer (MRE), a smart material, is an innovative material for base isolation system. It has magnetorheological (MR) effect that can control the stiffness in real-time. In this paper, a new hybrid base isolation system combining two electromagnetic closed circuits and the roller bearing is proposed. In the proposed system, the roller part can support the vertical load. Thus, the MRE part is free from the vertical load and can exhibit the maximum MR effect. The MRE magnetic loop is constructed in the free space of the roller bearing and forms a strong magnetic field. To demonstrate the performance of the proposed hybrid base isolation system, dynamic characteristic tests and performance evaluation were carried out. Dynamic characteristic tests were performed under the extensive range of strain of the MRE and the change of the applied current. Performance evaluation was carried out using the hybrid simulation under five earthquakes (i.e., El Centro, Kobe, Hachinohe, Northridge, and Loma Prieta). Especially, semi-active fuzzy control algorithm was applied and compared with passive type. From the performance evaluation, the comparison shows that the new hybrid base isolation system using fuzzy control algorithm is superior to passive type in reducing the acceleration and displacement responses of a target structure.

• Earthquakes and Structures
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• 제4권6호
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• pp.587-606
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• 2013

The given paper presents a new approach in design of seismic isolation systems of base isolated buildings. The idea is to install not one big size rubber bearing under the columns and/or shear walls, or one by one with certain spacing under the load-bearing walls, but to install a group/cluster of small size bearings, in order to increase the overall effectiveness of the isolation system. The advantages of this approach are listed and illustrated by the examples. Also the results of analyses of some buildings where the approach on installation of clusters of rubber bearings was used in their isolation systems are given for two cases: i) when the analyses are carried out based on the provisions of the Armenian Seismic Code, and ii) when the time history analyses are carried out. Obtained results are compared and discussed. Paper also presents, as an example, detailed analysis and design of the 18-story unique building in one of the residential complexes in Yerevan. Earthquake response analyses of this building were carried out in two versions, i.e. when the building is base isolated and when it is fixed base. Several time histories were used in the analyses. Comparison of the obtained results indicates the high effectiveness of the proposed structural concepts of isolation systems and the need for further improvement of the Seismic Code provisions regarding the values of the reduction factors. A separate section in the paper dedicated to the design of high damping laminated rubber-steel bearings and to results of their tests.

• 한국식품과학회지
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• 제51권6호
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• pp.604-609
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• 2019

To control pathogenic E. coli in biofilm, bacteriophages were isolated from environmental samples. Seventeen isolates had depolymerase activities by translucent zones at the rims of plaques. To determine biofilm-forming ability, an abiotic plastic surface of polystyrene was used; E. coli O103 showed the highest biofilm formation at 30℃ after 24 h. Moreover, biofilm by E. coli O103 on the biotic surface of lettuce was observed by a scanning electron microscope. The bacteriophage cocktail of ΦNOECP40 and ΦNOECP44 showing depolymerase activities was prepared to eliminate the E. coli inbiofilm. By organic acids, reduction of E. coli in biofilm was insignificant and almost undetectable. However, the abundance of E. coli in biofilm was reduced by 3 log CFU/mL from 7.3 log CFU/mL after 60 min with the bacteriophage cocktail. Therefore, we suggest that bacteriophages with depolymerase could be utilized to effectively control pathogenic E. coli in biofilm.