• 대한임상검사과학회지
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• 제45권1호
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• pp.5-8
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• 2013

In the specimen of free PSA in the low concentration, the result in % bias from our institution and comparable evaluation institution was -33.7% which is exceeded % bias ${\pm}20%$ ; however, it was the domestically allowable limit recommended by the laboratory accreditation commission for specimen at the low concentration. In this paper, the cause was accredited by instability of free PSA substance within the specimen, and the specimen stability test was performed according to CLSI documents GP29-A2. After the low and high concentration specimen were made, and rapidly cooled down in a deep freezer with $-30^{\circ}C$, serum of two concentrations was measured for 10 consecutive days with 3 times a day by Architect i2000 and observed a change in the mean value. As the results of two groups, there were changes in the established target value, and a change level was evaluated by calculating it with % bias. The low concentration specimen had no significant reduction until the 4 day lapse in cold storage. However, % bias were reduced by -17.5% from the 5 day lapse, by 21.5% after the 7 day lapse, and by -26.9% after the 9 day lapse. The frozen specimen had only intra-day variation for 10 days. In the high concentration specimen, bias began to show as -12.2% from the 3 day lapse in cold storage. There was reduction by -28.9% from the 5 day lapse, by -39% after the 7 day lapse, and by -42.9% after the 9 day lapse. In the frozen specimen, there was only intra-day variation like the low concentration specimen in cold storage.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.111.1-111.1
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• 2011

Recently, comsumption of fossil fuel is causing many problems(oilflation, global warming, environmental pollution). For this reason Renewable energy is now becoming the center of interest as a solution to these problems. Bioethanol, especially, is able to substitute petroleum as fuel; making it a viable and promising renewable energy. In order to production of fuel bioethanol, Dehydration process is essential. Azeotropic distillation, extractive and pressure swing absorption(PSA) process are some of possible dehydration process, out of which, PSA process is attractive since it required less energy and lower setup cost. In this study, we produced fuel bioethanol using 2-step PSA(3 bed + 2 bed) process for more efficient and economical process. Through this study, we produced fuel bioethanol using 2-step PSA process and concentration of fuel bioethanol was 99.54wt%(feed ethanol: 92.4wt%). We expected that because of efficient use of absorbents(zeolite), 2 step PSA process contribute to economical operation.

• Journal of Radiation Protection and Research
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• 제43권2호
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• pp.39-49
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• 2018

Background: A model to assess the activity concentration of agricultural products and the public ingestion dose as result of a nuclear accident is necessarily required to manage the contaminated agricultural systems by the accident, or to estimate the effects of chronic exposure due to food ingestion at a Level 3 PSA. Materials and Methods: A dynamic compartment model, which is composed of three sub-modules, namely, an agricultural plant contamination assessment model, an animal product contamination assessment model, and an ingestion dose assessment model has been developed based on Korean farming characteristics such as the growth characteristics of rice and stockbreeding. Results and Discussion: The application study showed that the present model can predict well the characteristics of the activity concentration for agricultural products and ingestion dose depending on the deposition date. Conclusion: The present model is very useful to predict the radioactivity concentration of agricultural foodstuffs and public ingestion dose as consequence of a nuclear accident. Consequently, it is expected to be used effectively as a module for the ingestion dose calculation of the Korean agricultural contamination management system as well as the Level 3 PSA code, which is currently being developed.

• 핵의학기술
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• 제27권1호
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• pp.29-35
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• 2023

Purpose The concentration of PSA (Prostate Specific Antigen) after radical prostatectomy in prostate cancer patients is a predictor of biochemical recurrence, and the AUA (American Urological Association) is defined as biochemical recurrence when the concentration of PSA is measured at 0.2 ng/mL or more, and when the concentration is measured at 0.2 ng/mL or more at the retest. This standard is also applied our hospital. In this laboratory, the PSA reagent using IRMA (Immunoradiometric Assay) is used, and the sensitivity at a very low value was not as good as the reagent used in the department of laboratory medicine. This study aims to increase the reliability of the results by improving the precision and sensitivity of very low values. Materials and Methods As a reagent for the study, PSA reagent using IRMA was used. As a method to improve the precision and sensitivity of very low values, a variation method on the serum volume(25 uL, 50 uL, 100 uL, 200 uL) was studied, and variation usefulness evaluation was conducted. The evaluation items were compared the results of precision, analytical sensitivity, recovery rate, dilution test, high-dose hook effect test, parallel test and very low concentration values(n = 20). Results The validation results were displayed in the order of 25 uL, 50 uL, 100 uL, 200 uL. As the serum volume increased, it was confirmed that CV (Coefficient of Variation)(%) improved. Analytical sensitivity(ng/mL) was 0.038, 0.041, 0.017, 0.015 and recovery rate(%) was 101±3, 101±3, 99±2, 97±4. very low concentration values(ng/mL) between each volume(n=20) were 0.135±0.068, 0.076±0.050, 0.048±0.034, 0.046±0.034. and high dose hook effect appeared as the serum volume increased. Conclusion Through the variation usefulness evaluation, it was confirmed that as the serum volume increased, the precision and sensitivity improved at very low concentration values. However, it is necessary to pay special attention to the occurrence of high-dose hook effect as the serum volume increases. In the case of tests that requires very low concentration values, it is thought that the reliability of the result will be increased if the variation method is properly used after the variation usefulness evaluation.

• Journal of Radiation Protection and Research
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• 제37권3호
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• pp.149-158
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• 2012

알파, 베타핵종의 분리측정에 효과적인 저준위 액체섬광계수기를 이용하여 부산 금정구의 10지점을 선정하여 1년 동안 지하수 내 라돈농도의 변화를 측정하였다. 액체섬광계수기의 최적화된 측정방법을 결정하기 위하여 라듐-226의 표준선원을 이용하여 효율과 백그라운드의 관계를 나타내는 FM (Figure of Merit) 값이 최대가 되는 PSA 준위가 100에서 110범위에 있음을 확인하였다. 결정된 PSA 준위에서 측정된 부산 금정구 지역의 각 암석 분포에 대한 지하수 내 라돈의 평균 농도를 비교해보면, 흑운모화강암 지역은 191.39 $Bq{\cdot}L^{-1}$, 미문상화강암 지역은 141.88 $Bq{\cdot}L^{-1}$, 아다멜라이트 지역은 92.94 $Bq{\cdot}L^{-1}$, 안산암 지역은 35.35 $Bq{\cdot}L^{-1}$ 순으로 나타났다. 조사지역의 10개 지점에서 1년간 정기적으로 측정된 라돈농도의 변화 양상을 살펴보면, 뚜렷하게 구분되는 특징적 계절적 변화양상이 나타나지 않고 있다. 지하수 내 라돈 농도와 수온, 기온, 대기압, 강수량의 상관성을 알아본 결과 각각에 대한 뚜렷한 연관성은 찾을 수 없었으며, 하나의 변수에 대해서가 아니라 보다 복합적 요인과 작용에 의해 변화한다고 판단된다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.5719-5723
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• 2013

Pharmacological and preventive properties of Petroselinum sativum seed extracts are well known, but the anticancer activity of alcoholic extracts and oil of Petroselinum sativum seeds on human breast cancer cells have not been explored so far. Therefore, the present study was designed to investigate the cytotoxic activities of these extracts against MCF-7 cells. Cells were exposed to 10 to $1000{\mu}g/ml$ of alcoholic seed extract (PSA) and seed oil (PSO) of Petroselinum sativum for 24 h. Post-treatment, percent cell viability was studied by 3-(4, 5-dimethylthiazol-2yl)-2, 5-biphenyl tetrazolium bromide (MTT) and neutral red uptake (NRU) assays, and cellular morphology by phase contrast inverted microscopy. The results showed that PSA and PSO significantly reduced cell viability, and altered the cellular morphology of MCF-7 cells in a concentration dependent manner. Concentrations of $50{\mu}g/ml$ and above of PSA and $100{\mu}g/ml$ and above of PSO were found to be cytotoxic in MCF-7 cells. Cell viability at 50, 100, 250, 500 and $1000{\mu}g/ml$ of PSA was recorded as 81%, 57%, 33%, 8% and 5%, respectively, whereas at 100, 250, 500, and $1000{\mu}g/ml$ of PSO values were 90%, 78%, 62%, and 8%, respectively by MTT assay. MCF-7 cells exposed to 250, 500 and $1000{\mu}g/ml$ of PSA and PSO lost their typical morphology and appeared smaller in size. The data revealed that the treatment with PSA and PSO of Petroselinum sativum induced cell death in MCF-7 cells.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1999년도 추계학술발표회 초록집
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• pp.16-17
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• 1999

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1999년도 추계학술발표회 초록집
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• pp.18-18
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• 1999

• 에너지공학
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• 제23권2호
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• pp.62-73
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• 2014

본 연구는 혐기성소화조에서 발생된 바이오가스로부터 바이오메탄을 생산하기 위한 고질화 공정의 운전조건을 최적화하기 위하여 반응표면 분석모델을 적용하였다. 반응표면 분석법의 하나인 Box-Behnken 설계법을 이용하였으며 바이오가스 고질화 공정의 메탄농도와 메탄회수율을 극대화하기 위한 수학적인 최적운전조건을 도출하였다. 도출된 반응표면모델의 적합성을 검증한 결과 각 모델의 p Value가 0.05 이하로서 유의성이 매우 높게 나타났으며, 결정계수($R^2$)는 각각 0.9788, 0.9710 이었다. 그리고 이산화탄소/메탄분리공정에서 메탄농도에 대해 운전압력이 가장 크게 영향을 미치고 다음으로 바이오메탄 생산량, PSA 회전밸브 속도의 순이다. 메탄회수율에 대해서는 PSA 회전밸브 속도가 가장 크게 영향을 미치고 있으며, 바이오메탄 생산량, 운전압력의 순으로 나타났다. 액체바이오 메탄 생산량이 $100Nm^3/hr$일 때의 최적 운전조건을 도출한 결과, 운전압력이 8.0bar 그리고 PSA 회전 밸브 속도가 31.55RPM일 때 바이오메탄의 메탄농도와 메탄회수율을 최대화할 수 있었고, 이때의 바이오메탄의 메탄농도는 97.13%이고, 메탄회수율은 75.89%이었다.

• 접착 및 계면
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• 제21권4호
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• pp.156-161
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• 2020

수계 압력감응점착제(PSA)는 유해성 휘발성유기용매 사용을 최소화할 수 있는 친환경 기술로써 학계와 산업계에서 큰 관심을 받아왔다. 수계 PSA의 합성은 유화중합을 이용하는데 이 때 이용되는 페놀계 계면활성제는 환경 및 인체유해성이 높아 이를 대체할 수 있는 신규 계면활성제 개발이 산업적으로 요구된다. 본 논문에서는 환경유해성 페놀계 CO-436 계면활성제를 대체할 수 있는 스티렌페놀계 계면활성제를 이용하여 수계 PSA를 합성하고 스티렌페놀계 계면활성제의 종류 및 농도에 따른 수계 PSA의 물성과 산업계 응용 가능성에 대해 알아보고자 한다.