• 상하수도학회지
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• 제19권6호
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• pp.791-799
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• 2005

The phased isolation intra-clarifier ditch system used in this study is a simplified novel process enhancing simultaneous removal of biological nitrogen and phosphorus in municipal wastewater in terms of elimination of additional pre-anaerobic reactor, external clarifier, recycle of sludge, and nitrified effluent recirculation by employing intrachannel clarifier. Laboratory-scale phased isolation ditch system was used to assess the treatability on municipal wastewater. When the system was operated at the HRTs of 6~12hours, SRTs of 9~31days, and cycle times of 2~8hours, the system showed removals of BOD, TN, and TP as high as 88~97%, 70~84%, and 65~90%, respectively. The rainfall in Korea is generally concentrated in summer because of site-specific characteristics. Especially, the wet season has set in on June to August. In combined sewers, seasonal variations are primarily a function of the amount of stormwater that enters the system. In order to investigate the effect of hydraulic shock loading on system performance, the laboratory-scale system was operated at an HRT of 6hours (two times of influent flowrate) during two cycles (8hours). The system performance slightly decreased by increasing of influent flowrate and decreasing of system HRT. Nitrification efficiency and TN removal were slightly decreased by increasing of influent flowrate (decreasing of system HRT), whereas, the denitrification was not affected by hydraulic shock loading. However, the higher system performance could be achieved again after four cycles. Thus, the phased isolation technology for enhanced biological nutrient removal in medium- and small-scale wastewater treatment plants suffering fluctuation of influent quality and flowrate.

• 한국콘텐츠학회논문지
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• 제22권10호
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• pp.349-358
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• 2022

본 연구는 코로나바이러스감염증-19 환자의 불확실성, 사회적 고립감, 사회적 지지와 극복력의 관계를 확인하고 극복력 관련 요인을 규명하고자 시도되었다. 자료는 2021년 3월 7일부터 5월 5일까지 수집되었고, 200부의 설문지가 자료분석에 이용되었다. 자료는 기술통계, t-test, ANOVA, Pearson correlation coefficient와 다중회귀분석을 사용하여 IBM SPSS Statistics 24.0을 이용하여 분석하였다. 분석결과, 사회적 고립감이 낮을수록, 사회적 지지가 높을수록, 격리에 대한 설명에 만족한 경우, 경제상태가 '중'인 경우 극복력이 높게 나타나는 것으로 확인되었다. 따라서 코로나바이러스감염증-19 환자의 극복력을 향상시키기 위해서는 가족과 의료인을 통해 사회적 지지를 강화시키고, 비대면 상담 등을 통해 사회적 고립감을 감소시키며, 질병에 대한 충분한 정보를 제공과 경제적 지원이 포함된 체계적인 관리 프로그램을 개발하여 적용하는 것이 필요하다.

• Structural Engineering and Mechanics
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• 제65권6호
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• pp.771-784
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• 2018

This study aims to investigate the stochastic response of isolated and non-isolated highway bridges subjected to spatially varying earthquake ground motion model. This model includes wave passage, incoherence and site response effects. The wave passage effect is examined by using various wave velocities. The incoherency effect is investigated by considering the Harichandran and Vanmarcke coherency model. The site response effect is considered by selecting homogeneous firm, medium and soft soil types where the bridge supports are constructed. The ground motion is described by power spectral density function and applied to each support point. Triple concave friction pendulum (TCFP) bearing which is more effective than other seismic isolation systems is used for seismic isolation. To implement seismic isolation procedure, TCFP bearing devices are placed at each of the support points of the deck. In the analysis, the bridge selected is a five-span featuring cast-in-place concrete box girder superstructure supported on reinforced concrete columns. Foundation supported highway bridge is regarded as three regions and compared its different situation in the stochastic analysis. The stochastic analyses results show that spatially varying ground motion has important effects on the stochastic response of the isolated and non-isolated bridges as long span structures.

• Computers and Concrete
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• 제9권3호
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• pp.195-213
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• 2012

This paper presents the investigation of the stochastic responses of seismically isolated bridges subjected to spatially varying earthquake ground motions including incoherence, wave-passage and site-response effects. The incoherence effect is examined by considering Harichandran and Vanmarcke coherency model. The effect of the wave-passage is dealt with various wave velocities in the response analysis. Homogeneous firm, medium and soft soil conditions are selected for considering the site-response effect where the bridge supports are constructed. The ground motion is described by filtered white noise and applied to each support points. For seismic isolation of the bridge, single and double concave friction pendulum bearings are used. Due to presence of friction on the concave surfaces of the isolation systems, the equation of motion of is non-linear. The non-linear equation of motion is solved by using equivalent linearization technique of non-linear stochastic analyses. Solutions obtained from the stochastic analyses of non-isolated and isolated bridges to spatially varying earthquake ground motions compared with each other for the special cases of the ground motion model. It is concluded that friction pendulum systems having single and double concave surfaces have important effects on the stochastic responses of bridges to spatially varying earthquake ground motions.

• 전산구조공학
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• 제7권1호
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• pp.83-90
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• 1994

국내의 설계지진은 상대적으로 작은규모 이지만 일점고정 연속교에 있어서는 지진시 교축방향의 고정지점에 상부구조의 모든 관성력이 집중됨에 따라 그 교각과 기초구조에는 상당히 큰 교축방향 수평력이 작용하게 된다. 기존의 교량의 내진설계 방법에서는 교각의 비탄성거동에 의존하는 수정응답계수를 사용하여 교각의 설계하중을 낮추어 설계에 사용하고 있으나 이는 교각의 비탄성거동으로 인한 손상과 그에 따른 큰 상부구조의 변위를 초래할 가능성이 있다. 본 연구에서는 내진분리베어링이 설치된 교량의 비선형 동적 방법을 제시하고 대표적인 내진분리베어링인 lead-rubber 베어링을 고정받침대신 사용하였을 경우 국내 설계 응답스펙트럼에 상응하는 지반운동하에서 교량의 응답특성을 살펴보았다. 내진분리베어링이 설치된 교량의 비선형 동적해석을 통해 1초이하 주기의 교량에 있어서 lead-rubber 베어링의 사용은 상당한 교축방향의 수평력 감소효과를 가져오며 상부구조의 수평변위도 그리 크지 않음을 보였다. 따라서 교량의 내진설계시 내진분리베어링의 사용으로 경제성과 내진안전성을 동시에 얻을 수 있을 것이다.

• 한국어병학회지
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• 제19권2호
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• pp.119-126
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• 2006

본 연구에서는 Vibrio harveyi의 주요 병원성 인자로 알려져 있는 ECPs를 분리하는 적정 조건을 제시하고자 하였다. 5 개의 분리균주 (FF8, FF10, FR1, FR2 and FT1 strain)와 2 개의 참조균주 (ATCC 35084 및 ATCC 14126)의 ECPs를 다양한 조건에서 분리해 본 결과, 1.5% NaCl 첨가 TSA 배지에서 25℃, 24 시간 배양하는 것이 가장 좋으며, ECPs 분리시의 buffer system은 pH 8.0이 적정한 것으로 나타났다. 나아가 우리 나라에서 분리한 5 개의 분리 균주들의 주요 ECPs 성분이 serine protease인 것으로 조사되었다.

• Journal of Microbiology
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• 제43권3호
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• pp.266-271
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• 2005

In eukaryotic cells, various proteins are anchored to the plasma membrane through glycosylphosphatidylinositol (GPI). To study the biosynthetic pathways and modifications of GPI, various mutant cells have been isolated from the cells of Chinese hamster ovaries (CHO) supplemented with several exogenous genes involved in GPI biosynthesis using aerolysin, a toxin secreted from gram-negative bacterium Aeromonas hydrophila. Alpha toxin from Gram-positive bacterium Clostridium septicum is homologous to large lobes (LL) of aerolysin, binds GPI-anchored proteins and possesses a cell-destroying mechanism similar to aerolysin. Here, to determine whether alpha toxins can be used as an isolation tool of GPI-mutants, like aerolysin, CHO cells stably transfected with several exogenous genes involved in GPI biosynthesis were chemically mutagenized and cultured in a medium containing alpha toxins. We isolated six mutants highly resistant to alpha toxins and deficient in GPI biosynthesis. By genetic complementation, we determined that one mutant cell was defective of the second subunit of dolichol phosphate mannose synthase (DPM2) and other five cells were of a putative catalytic subunit of inositol acyltransferase (PIG-W). Therefore, C. septicum alpha toxins are a useful screening probe for the isolation of various GPI-mutant cells.

• 대한미생물학회지
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• 제9권1호
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• pp.13-18
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• 1974

Blood is one of the most important clinical specimens for the isolation of bacteria. A rapid isolation and a high isolation rate of bacteria are very important in blood culture because bacteremic patients are mostly in grave condition. Various blood culture media which support growth of most fastidious bacteria are available commercially. However, growth of bacteria are frequently delayed because of antibacterial activity of blood. Sodium polyanethol sulfonate(Liquoid) has been reported to inactivate the antibacterial substance and disrupt phagocytic cells. The beneficial effect of SPS is well recognized in the isolation of gram-positive bacteria. However, the effect does not seem to be prominent for gram-negative bacilli isolation mainly due to the rapidity of their growth. It has been experienced with Sal. typhi that the growth is much slower than that of other gram-negative bacilli. For the rapid growth of the organism, use of bile broth has been recommended. Although Sal. typhi is the most frequently isolated organism at present, about one half of total isolates are other organisms and, in case bile broth is used, other media which support growth of these organisms should be used together. Fluid thioglycollate medium(FTM) which is always used in blood culture to isolate anaerobes is inferior to brain heart infusion(BHI) for the isolation of aerobes. This study was done to determine the effect of SPS on the isolation of Sal. typhi from blood. During the Sep. 1973 to Sep. 1974 study period, 2460 blood cultures were made from the Severance hospital patients: BHI and FTM sets 1431 specimens, BHI with SPS(0.05%) and FTM sets 396 specimens, BHI and FTM with SPS sets 359 specimens, BHI and BHI with SPS sets 274 specimens. Mean incubation time required for the macroscopic detection of growth of Sal. typhi were 3.5 days on BHI and 2.7 days on BHI with SPS. The 0.8 day difference was statistically significant. On FTM the mean incubation time was 3.8 days while it was 2.9 days on FTM with SPS. The 0.9 day difference was statistically significant. The result on BHI with and without SPS sets showed faster growth on BRI with SPS in 7 specimens and slower growth in one specimen and the remaining 12 showed growth at the same time. These specimens had mean incubation time of 3.2 days on BHI and 2.3 days on BHI with SPS. The 0.9 day difference was statistically significant. This study indicates beneficial effect of SPS for the rapid isolation of Sal. typhi from clinical blood specimens.

• 한국동물위생학회지
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• 제22권3호
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• pp.221-237
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• 1999

To investigate the specificity of rapid slide agglutination test for pullorum-gallinarum diseases and to obtain a basic data for avian salmonellosis control, salmonella isolation was peformed for the layer chickens positively reacted in pullonlm-typhoid agglutination test. The biochemical, serological and antimicrobial properties of the isolates were examined. The results obtained through this study were summarized as follows; 1. Of 2,384 chickens tested by the agglutination test, 606 chickens (25.4%) were positive reactors. 154 of 606 reactors and 49 of the non-reacting chickens were investigated for salmonella isolation, resulting in isolation of 68 strains of salmonellae from 27 chickens. 2. By organs, the isolation frequency from liver, cecum, spleen, ovary and gall bladder showed 8.9% (18 strains), 8.9% (18 strains), 7.4% (15 strains), 4.4% (9 strains) and 3.9% (8 strains), respectively. 3. By culture medium the combination of selenite broth and MacConkey agar revealed the highest isolation rate and the enrichment culture by delayed secondary enrichment culture method was found the most effective for salmonella isolation. 4. The serotypes of 68 salmonella isolates were identified as 3 strains of S pullorum, 24 strains of S gallinarum, 15 strains of S typhimurium, 8 strains of S enteritidis, 7 strains of S paratyphi A, 5 strains of S typhimurium and 6 strains of the other salmonellae. 5. The serotypes of 8 salmonella strains isolated from 49 chickens non-reacting in pullorum-typhoid agglutination test were identified as 3 strains of S typhimurium and 5 strains of S infantis. 6. When 24 chickens of which 68 strains of salmonellae isolated were examined by microplate agglutination test, the average antibody titer for pullorum antigen was $2^{5.25}$. The chickens at antibody titer between $2^3$ and $2^5$ showed the higher frequency of isolation as compared with the chickens at the other titers. 7. When salmonella isolates were tested the antimicrobial drug sensitivity by disk diffusion method, S paratyphi A were highly sensitive by 100% to ATM and GM, S typhimurium, by 88% to AM, CIP, IMP and TN, S infantis, by 100% to AM, CRO, ENR and PIP, S enteritidis,by 100% to IMP and PIP, S pullorum, by 100% to ATM, CRO, ENR and PIP and S gallinarum, by 92% to CRO, CIP and PIP.

• Mycobiology
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• 제40권1호
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• pp.42-46
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• 2012

This report describes the isolation and identification of a potent acetylcholinesterase (AChE) inhibitor-producing yeasts. Of 731 species of yeast strain, the S-3 strain was selected as a potent producer of AChE inhibitor. The selected S-3 strain was investigated for its microbiological characteristics. The S-3 strain was found to be short-oval yeast that did not form an ascospore. The strain formed a pseudomycelium and grew in yeast malt medium containing 50% glucose and 10% ethanol. Finally, the S-3 strain was identified by its physiological characteristics and 26S ribosomal DNA sequences as $Yarrowia$ $lipolytica$ S-3.