• KSBB Journal
• /
• v.23 no.6
• /
• pp.484-488
• /
• 2008

Chlorinated phenols are widely used by the chemical industry as intermediate products in synthesis and previously were frequently applied to various industry fields. Peroxidases catalyze the peroxide-dependent oxidation of a range of inorganic and organic compounds. Peroxidase was shown to mineralize a variety of recalcitrant aromatic compounds and to oxidize a number of polycyclic aromatic and phenolic compounds. Among monomeric phenolic and nonphenolic compounds, peroxidase is known to oxidize its compounds. In this study, a colorimetric assay was developed to quantitatively evaluate the peroxidase activity for rapid screening. Color products of different intensity were developed proportionally to the peroxidase activity on agar plate and 96-well plate. This method correlates well with the RP-HPLC result. Using this screening method, 12 colonies of strain was screened which survived at high concentration of 2,4-DCP (1000 ppm) and with peroxidase activity for the $7^{th}$ round screening step on agar plate. These strains were utilized 2,4-DCP as a sole carbon source and produced peroxidase. After the screening test, four of the bacteria have significant better effect of COD removal on dye waste-water. COD removal of these was from 44% to 61%, respectively.

• Journal of Soil and Groundwater Environment
• /
• v.14 no.2
• /
• pp.45-53
• /
• 2009

A quick and simple detection method of explosive compounds in environmental matrix (soil and water) can provide a screening step which reduces the number of unnecessary samples and the cost of expensive laboratory analysis at a site investigation. A commercially available EXPRAY$^{(R)}$Explosives Field Detection Kit (EXPRAY) was used to determine the minimum detection concentration and to test the possibility of semi-quantitative analysis of 14 explosive compounds using standard solutions. The results showed that EXPRAY could detect 5 explosive compounds, TNT, RDX, HMX, Tetryl, and TNB, out of 14 US EPA designated explosives. The minimum detection limit of the nitramine explosives was 14 ng/$^2$ for HMX and RDX. EXPRAY was more sensitive to nitroaromatics than the nitramines and the minimum detection limits per unit area (mm$^2$) for Tetryl, TNB, and TNT, were 3 ng, 3 ng, and 0.3 ng, respectively. The semi-quantification of 5 explosive compounds in an order ofmagnitude could be achieved by the intensity of developed color only when EXPRAY was applied on the standard solutions under controlled laboratory conditions. With contaminated soil samples, however, only the presence and type of explosive compounds was identified. Therefore, EXPRAY is an economic and sensitive method that can be used in a screening step for the identification of explosives in the field samples.

• Korean Journal of Soil Science and Fertilizer
• /
• v.34 no.2
• /
• pp.145-146
• /
• 2001

본 분석방법은 토양중에 방향성화합물을 함유한 유류 존재를 스크리닝하는 방법으로 ASTM(The American Society for Testing and Materials)에 등록되어 있으며, 수분 제거제를 이용하여 토양수분에 의한 정량 오차를 줄이고 UV-Spectrophotometer로 정량한다. 오염된 유류의 종류를 알고 있으나 동일한 유류를 구하지 못할 경우에는 일반적으로 동일종에서 얻어진 계수로 농도를 추정하며, 오염된 유류의 특성을 모를 경우에는 본 방법으로 오염여부 판단만이 가능하다. 그러나 토양에 오염된 것과 동일한 유류로 검량선을 작성할 경우에는 대략적인 정량도 가능하며, 분석방법을 요약하면 다음과 같다. 일정량의 토양시료에 CaO를 첨가하여 토양수분에 의한 영향을 제거한 뒤 이소프로필알콜(isopropyl alcohol)로 추출하여 여과한다. 여과액을 254nm의 UV파장에서 흡광도를 측정하여 오염된 것과 동일한 유류로 작성된 검량선을 이용하여 정량한다.

• Journal of Applied Biological Chemistry
• /
• v.56 no.3
• /
• pp.137-139
• /
• 2013

Free radical scavengers in the bisdemethoxycurcumin (BDMC), demethoxycurcumin (DMC) and curcumin of turmeric (Curcuma longa) were screened, identified, quantified and isolation using coupled off-line-2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and on-line screening high-performance liquid chromatography (HPLC)-ABTS assay. There was a very small margin of error between the off-line-ABTS method and the on-line screening HPLC-ABTS method.

• Environmental engineer
• /
• v.24 s.256
• /
• pp.23-25
• /
• 2007

건강영향의 중요성에 대한 인식이 증가함에 따라, 본 연구는 건강영향평가의 최적 도입방안을 연구하는데 목적을 둔다. 한국의 지난 30년 동안 환경영향평가(EIA)를 수행하고 있다. EIA내의 스크리닝, 스코핑, 분석, 영향평가, 협의, 보고서 검토, 의사결정 및 모니터링 과정들은 HIA의 필수적인 부분이 될 것이다. 스크리닝 및 스코핑 과정은 아직 EIA내에 포함되어 있지는 않지만, 기존 EIA 과정내로 HIA를 통합하는 것은 한국에서 매우 효율적인 방안이 될 수 있다. 나아가, EIA내의 기존 공중-위생 항목을 보건 영향을 고려하기 위해 충분한 결정인지를 지닌 환경-보건항목으로 교체 및 확장하는 것이 바람직할 것이다. 한국의 경우, HIA의 초기 시행을 고려할 때 사회과학 및 심리학에 기초한 전향적 및 정량적 접근법이 보다 적합할 것이다. 본 연구에서는, 체크리스트와 툴키트가 개발되었으며, HLA의 적용 및 보급에 있어 매우 유효한 지침이 될 수 있을 것이다.

• Journal of Marine Life Science
• /
• v.8 no.1
• /
• pp.68-77
• /
• 2023

In this study, we investigated the quantitative distribution of microplastics in the surface seawater at 8 points near the Taean Peninsula using fluorescence staining. The study revealed a detection range of microplastics from 0 to 360.5 particles/l, with an average of 149.7 ± 46.0 particles/l. When classifying the microplastics by size, it was found that particles smaller than 50 ㎛ were dominant, although there were differences at Site 3. Moreover, it was not possible to identify clear correlations when comparing the number of microplastics based on collection area and particle size. Various physical and chemical factors, including plastic material, dynamic ocean conditions (such as currents, wind, waves, tides), geological characteristics (topography, slope), sediment materials including coastal organisms, human activities (fishing, development, tourism), and weather conditions (floods, rainfall), affect the behavior of microplastics. Therefore, future efforts should focus on standardizing quantitative analysis methods and conducting fundamental research on microplastic monitoring, including the analysis of environmental factors.

• Proceedings of the Korean Society for Bioinformatics Conference
• /
• 2006.02a
• /
• pp.38-44
• /
• 2006

프로테오믹스는 생물체 안에 포함되어 있는 단백질을 통합적으로 연구하는 학문이다. 단백질을 동정(Protein identification)하고, 단백질의 상태를 분석(Protein characterization)하며, 단백질의 양적 변화를 관찰(Protein quantitation)한다. 유전자로부터 mRNA 로 복제되고 codon 의 규칙에 따라 합성되는 단백질이 세포 내에 얼만큼 존재하는가라는 단백질의 양적인 변화는 세포 내의 환경에 따라 시시각각 변화할 수 있으며, 이러한 변화의 추적은 단백질의 기능을 밝히는 기초자료로서 중요성을 가진다. 특히 질병의 조기 진단을 위한 바이오마커를 발굴하기 위한 스크리닝 역할로서, 단백질의 발현 양상을 비교하는 프로테오믹스는 기대를 모으고 있다. 단백질에 대한 분석, 특히 질량분석기에 의해 초고속으로 대량의 단백질 데이터를 생산하는 프로테오믹스의 연구는 정량적인 단백질 발현양상 분석의 정확도를 높이기 위해 다양한 실험기법과 데이터 분석기법을 동원하고 있다. 이번 발표에서는 프로테오믹스에서 단백질의 양을 측정하기 위한 실험 방법들과 그에 따른 데이터 분석 방법들을 소개하고자 한다. 프로테오믹스 연구의 초창기부터 사용되어온 2차원 전기영동법에 의해 생성되는 2D-gel image 에서의 spot 분석법으로부터, 탄뎀 질량분석기를 사용하는 ICAT, iTRAQ 등의 labeling 방법에 의한 정량분석, 그리고 질량분석기의 정확도를 최대한으로 활용하는 label-free 방법에 대한 기본 개념을 살펴보고 데이터 분석 기술의 적용 방법을 알아본다.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.7
• /
• pp.544-551
• /
• 2011

The objective of this study was to analyze VIRULO model, a probabilistic quantitative model, which had been developed by US Environmental Protection Agency. The model could assess the viral attenuation capacity of soil as hydrogeologic barrier using Monte Carlo simulation. The governing equations used in the model were composed of unsaturated flow equations and viral transport equations. Among the model parameters, those related to water flow for 11 soil types were from UNDODA data, and those related to 5 virus species were from the literatures. The model compared the attenuation factor with threshold of attenuation to determine the probability of failure and presented the exceedances and Monte Carlo runs as output. The analysis indicated that among 11 USDA soil types, the viral attenuation capacity of loamy sand and sand were far lower than those of clay and silt soils. Also, there were differences in the attenuation in soil among 5 viruses with poliovirus showing the highest attenuation. The viral attenuation capacity of soil decreased sharply with increasing soil water content and increased nonlinearly with increasing soil barrier length. This study indicates that VIRULO model could be considered as a useful screening tool for viral risk assessment in subsurface environment.

• Analytical Science and Technology
• /
• v.23 no.1
• /
• pp.1-14
• /
• 2010

It is of importance that all countries in worldwide, including EU and China, have adopted the Restrictions on the use of certain Hazardous Substances (RoHS) for all electronics. IEC62321 document, which was published by the International Electronics Committee (IEC) can have conflicts with the standards in the market. On the contrary Publicly Accessible Specification (PAS) for sampling published by IEC TC111 can be adopted for complementary application. In this work, we tried to find a route to disassemble and disjoint cellular phone sample, based on PAS and compare the screening methods available in the market. For this work, the cellular phone produced in 2001, before the regulation was born, was chosen for better detection. Although X-ray Fluorescence (XRF) showed excellent performance for screening, fast and easy handling, it can give information on the surface, not the bulk, and have some limitations due to significant matrix interference and lack of variety of standards for quantification. It means that screening with XRF sometimes requires supplementary tool. There are several techniques available in the market of analytical instruments. Laser ablation (LA) ICP-MS, energy dispersive (ED) XRF and scanning electron microscope (SEM)-energy dispersive X-ray (EDX) were demonstrated for screening a cellular phone. For quantitative determination, graphite furnace atomic absorption spectrometry (GF-AAS) was employed. Experimental results for Pb in a battery showed large difference in analytical results in between XRF and GF-AAS, i.e., 0.92% and 5.67%, respectively. In addition, the standard deviation of XRF was extremely large in the range of 23-168%, compared with that in the range of 1.9-92.3% for LA-ICP-MS. In conclusion, GF-AAS was required for quantitative analysis although EDX was used for screening. In this work, it was proved that LA-ICP-MS can be used as a screening method for fast analysis to determine hazardous elements in electrical products.

• The Korean Journal of Applied Statistics
• /
• v.31 no.1
• /
• pp.123-137
• /
• 2018

A nonlinear mixed effects model is mainly used to analyze repeated measurement data in various fields. A nonlinear mixed effects model consists of two stages: the first-stage individual-level model considers intra-individual variation and the second-stage population model considers inter-individual variation. The individual-level model, which is the first stage of the nonlinear mixed effects model, estimates the parameters of the nonlinear regression model. It is the same as the general nonlinear regression model, and usually estimates parameters using the least squares estimation method. However, the least squares estimation method may have a problem that the estimated value of the parameters and standard errors become extremely large if the assumed nonlinear function is not explicitly revealed by the data. In this paper, a new estimation method is proposed to solve this problem by introducing the ridge regression method recently proposed in the nonlinear regression model into the first-stage individual-level model of the nonlinear mixed effects model. The performance of the proposed estimator is compared with the performance with the standard estimator through a simulation study. The proposed methodology is also illustrated using quantitative high throughput screening data obtained from the US National Toxicology Program.