• Journal of Genetic Medicine
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• 제12권2호
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• pp.72-78
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• 2015

Recently, noninvasive prenatal test (NIPT) has been adopted as a primary screening tool for fetal chromosomal aneuploidy. The principle of NIPT lies in isolating the fetal fraction of cell-free DNA in maternal plasma and analyzing it with bioinformatic tools to measure the amount of gene from the target chromosome, such as chromosomes 21, 18, and 13. NIPT will contribute to decreasing the need for unnecessary invasive procedures, including amniocentesis and chorionic villi sampling, for confirming fetal aneuploidy because of its higher positive predictive value than that of the conventional prenatal screening method. However, its greater cost than that of the current antenatal screening protocol may be an obstacle to the adoption of this innovative technique in clinical practice. Digital polymerase chain reaction (dPCR) is a novel approach for detecting and quantifying nucleic acid. dPCR provides real-time diagnostic advantages with higher sensitivity, accuracy, and absolute quantification than conventional quantitative PCR. Since the groundbreaking discovery that fetal cell-free nucleic acid exists in maternal plasma was reported, dPCR has been used for the quantification of fetal DNA and for screening for fetal aneuploidy. It has been suggested that dPCR will decrease the cost by targeting specific sequences in the target chromosome, and dPCR-based noninvasive testing will facilitate progress toward the implementation of a noninvasive approach for screening for trisomy 21, 18, and 13. In this review, we highlight the principle of dPCR and discuss its future implications in clinical practice.

• Nuclear Engineering and Technology
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• 제52권2호
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• pp.287-295
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• 2020

Group method of data handling (GMDH) is considered one of the earliest deep learning methods. Deep learning gained additional interest in today's applications due to its capability to handle complex and high dimensional problems. In this study, multi-layer GMDH networks are used to perform uncertainty quantification (UQ) and sensitivity analysis (SA) of nuclear reactor simulations. GMDH is utilized as a surrogate/metamodel to replace high fidelity computer models with cheap-to-evaluate surrogate models, which facilitate UQ and SA tasks (e.g. variance decomposition, uncertainty propagation, etc.). GMDH performance is validated through two UQ applications in reactor simulations: (1) low dimensional input space (two-phase flow in a reactor channel), and (2) high dimensional space (8-group homogenized cross-sections). In both applications, GMDH networks show very good performance with small mean absolute and squared errors as well as high accuracy in capturing the target variance. GMDH is utilized afterward to perform UQ tasks such as variance decomposition through Sobol indices, and GMDH-based uncertainty propagation with large number of samples. GMDH performance is also compared to other surrogates including Gaussian processes and polynomial chaos expansions. The comparison shows that GMDH has competitive performance with the other methods for the low dimensional problem, and reliable performance for the high dimensional problem.

• ALGAE
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• 제32권3호
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• pp.189-197
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• 2017

To quantify the abundance of the harmful dinoflagellate Cochlodinium polykrikoides in natural seawaters, we developed the innovative procedure using a droplet digital PCR (ddPCR) with C. polykrikoides-specific primers targeting the internal transcription sequence (ITS). The abundance of C. polykrikoides was estimated by the specific copy number of target ITS DNA segments per cell in cultures and natural water samples. The copy number per C. polykrikoides cell as acquired by ddPCR was $157{\pm}16$, which was evaluated against known cell numbers through a simplified protocol preparing DNAs. The abundances of C. polykrikoides in the waters of different locations estimated by ddPCR agreed with the number of cells visually counted under a microscope. This protocol was used to measure the abundance of C. polykrikoides close to and further off the southern coast of Korea in August of 2016 and 2017. The practical application showed that this method can reduce time for analysis and increase accuracy.

• 한국정밀공학회지
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• 제9권1호
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• pp.82-95
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• 1992

There is the high interest for sensing of tool wear with the aim of controlling machine tools productivity from the point of view of qualitity. Difficulties in this measurement are also known. This study is on the development of measurement setup for crater wear by CCD image inturning. In this study, the crater wear measurement system consists of the He-Ne gas laser, diffraction grating. CCD camera, noise filter, slit, microcomputer, diverging lens, converging lens and so on. He-Ne laser beam passes through a diverging lens and a diffraction grating is positioned properly. A converging lens focuses so that the interference fringes can be obtained on the crater wear. Performance test revealed that the developed image technique provides precise, absolute tool-wear quantification and reduces human measurement errors. The results obtained are as follows 1. The digitizing of one image requires less than 2ses. 2. It can give detailed information on crater wear with limited times and errors 3. All parameters required by specification are easily obtained for several points of the cutting edge.

• Asian-Australasian Journal of Animal Sciences
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• 제11권3호
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• pp.209-216
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• 1998

The paper presented here is aimed at increasing knowledge on purine metabolism in ruminants and hence the quantification of microbial cells entering the small intestine from urinaη excretion of purine derivatives. Nucleic acid metabolisms of micro-organisms in the rumen, digestion and absorption of nucleic acids entering the intestines, metabolisms of absorbed and endogenous purines involving de novo synthesis of nucleic acids in the ruminants host, and the relationship between absorbed and excreted purines are reviewed. Principal concerns about an amount of purine derivatives excreted in urine in relation to a change in purine-N: total-N ratios in rumen microbes that leave the rumen are discussed. The use of urinary excretion of purine derivatives as an indicator of the amount of microbial biomass leaving the rumen has to be done with some caution since it may be impossible to get a representative sample of microbes entering the intestine and thus yield estimates are relative rather than absolute.

• 대한의생명과학회지
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• 제21권4호
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• pp.241-247
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• 2015

Lactate and ketone bodies are considered biological markers for ketosis and several inherited metabolic disorders. In the current study, the specific ratios of lactate and ketone bodies as analytical tools for differential diagnosis of various lactic acidosis were devised. The study included a protein precipitation step following tert-butyldimethylsilyl derivatisation. Total run time was approximately 30 min including sample preparation and GS/MS analysis. The limits of detection were below 0.1 pg/mL over the targeted 4 analytes. The calibration curve was linear over the concentration range of $0.001{\sim}250{\mu}g/mL$ for pyruvate, beta-hydroxybutyrate, and acetoacetate ($R^2$ > 0.99). Inter-day accuracy and precision were 87.7~94.8% with RSD of 2.5~5.7% at 2 levels. Absolute recoveries (%) of target analytes were 87.0~98.4%. The method was validated for the quantification of lactate and ketone bodies for differentiation of lactic acidosis.

• 한국산림과학회지
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• 제97권4호
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• pp.437-444
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• 2008

본 연구는 자연휴양림 내에서 휴양지구를 설정하기 위한 방법을 모색하기 위하여 산림휴양기능의 평가를 시도하였다. 청옥산 자연휴양림을 연구대상지로 선정하고, 표준지 173개 소반을 추출하여 수량화II류를 이용하여 분석하였다. 이때 외적기준은 산림휴양 효용의 정도를 전문가로부터 부여받았고, 설명변수는 기존의 연구결과와 대상지의 산림휴양자원을 고려하여 임상, 임령, 경사, 수변, 도로, 시설의 6인자를 선정하였다. 그 결과, 절대판별적중률은 제 1 2상관비 축에서 각각 82%, 75%로서 예측 가능한 판별 정도(精度)를 얻었다. 요인으로서는 도로와 경사가 산림휴양기능의 잠재력에 큰 영향을 미치고 있으며, 카테고리에 있어서는 도로가 있는 것이, 경사는 낮을수록 산림휴양기능을 높이는 방향으로 작용하는 것을 알 수 있었다. 또한, 청옥산 자연휴양림의 소반별 산림휴양기능의 잠재력을 평가하기 위하여 표준지에서의 예측식을 사용하여 산림휴양효용의 정도를 나타내는 종합점수를 구한 다음, 판별구분점에 의하여 높다(H), 보통(M), 낮다(L)로 3구분하였으며, GIS를 이용하여 분포를 나타내는 평가도를 작성하였다. 수량화라는 형식을 매개로 하여 산림휴양의 효용의 정도에 관한 현실의 직관적 경험적 종합판단을 평가인자와 카테고리가 개입된 분석적 판단으로 변환하고 있는 점에 본 연구의 의의가 있다.

• Investigative Magnetic Resonance Imaging
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• 제12권2호
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• pp.100-106
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• 2008

본 연구는 in vivo 보다 더욱 정확하게 뇌 대사물질을 정량 분석하고자 고자장 NMR 장비 (500MHz; 11.74T)를 이용하여 동물의 뇌를 in vitro 환경에서 조사 및 분석하였다. 일반적으로 in vivo 실험은 생체 내부의 혈류나 조직의 비균질성으로 인한 자기공명분광법의 shimming에 악영향을 미치기 때문에 부정확한 결과를 산출할 수 있다. 그러나, in vitro 실험은 이에 비하여 균질한 샘플을 사용하고 보다 고자장에서 실험환경을 조성할 수 있기 때문에 더욱 정확한 대사물질의 정보를 얻을 수 있다. 본 연구에서는 개 (canine)의 소뇌 (cerebellum)조직으로부터 대사물질을 추출하고 고자장 핵자기공명분광법으로 대사물질의 절대농도를 획득 하고자 하였다. 생체 대사물질의 절대농도를 획득하기 위하여 대표적인 대사물질(i.e., NAA, Cr, Cho, Ins, Lac, GABA, Glu, Gln, Tau Ala)의 팬톰을 제작하여 그 스펙트럼을 확보하였고, 개의 소뇌 부위를 적출하여 methanol-chloroform water extraction (M/C water extraction) 방법으로 대사물질만을 추출한 후 자기공명분광법을 수행하였다. 필터링 (filtering)의 효과를 평가하기 위하여 샘플 제작 시 추출물을 필터링한 그룹과 필터링하지 않은 그룹으로 분류하여 실험을 수행하였다. 팬텀 물질과 추출물은 90% D2O 수용액으로 만든 후 5mm NMR 튜브에 담아 실험하였다. 실험 결과 조직 추출물을 필터링하는 것이 신호대잡음비(signal to noise ratio: SNR, S/N)를 향상시키는 데 기여하는 것을 확인하였다. 또한 개의 소뇌 대사물질의 절대농도는 사람보다는 쥐 (rat)의 뇌 대사물질 절대농도와 더 비슷한 것을 확인할 수 있었다. 본 연구 결과를 토대로 고자장 핵자기공명분광법을 이용한 in vitro 실험은 뇌조직 내 대사물질의 절대농도를 측정하고 기본적인 지표를 확보하는데 매우 정확하고 정량적인 방법이 될 수 있을 것으로 사료된다.

• 센서학회지
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• 제27권6호
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• pp.397-402
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• 2018

Proper seat design is critical to the safety, comfort, and ergonomics of automotive driver's seats. To ensure effective seat design, quantitative methods should be used to evaluate the characteristics of automotive seats. This paper presents a system that is capable of simultaneously monitoring body pressure distribution and surface deformation in a textile material. In this study, a textile-based capacitive sensor was used to detect the body pressure distribution in an automotive seat. In addition, a strain gauge sensor was used to detect the degree of curvature deformation due to high-pressure points. The textile-based capacitive sensor was fabricated from the conductive fabric and a polyurethane insulator with a high signal-to-noise ratio. The strain gauge sensor was attached on the guiding film to maximize the effect of its deformation due to bending. Ten pressure sensors were placed symmetrically in the hip area and six strain gauge sensors were distributed on both sides of the seat cushion. A readout circuit monitored the absolute and relative values from the sensors in realtime, and the results were displayed as a color map. Moreover, we verified the proposed system for quantifying the body pressure and fabric deformation by studying 18 participants who performed three predefined postures. The proposed system showed desirable results and is expected to improve seat safety and comfort when applied to the design of various seat types. Moreover, the proposed system will provide analytical criteria in the design and durability testing of automotive seats.

• 농촌계획
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• 제16권3호
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• pp.27-41
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• 2010

This study developed a settlement environment diagnostic indices (SEDI) of rural villages which can apply to analyze variable conditions of villages having development projects. The index consists of 5 diagnostic areas (first level) with 13 items (second level), including detail indices of 40 criteria (third level) defined by specialists' brainstorming process. In order to develop the index system, object-oriented approach was used to extract the 5 diagnostic areas (infra-basic settlement facility, life condition & environmental resources, industry & economic infrastructure, community, and residents) from rural villages. For the 40 criteria, it was introduced a quantification method that all villages have absolute values in national level, not relative value between villages within an unit area. The diagnostic diagram and table were developed to evaluate the villages compositively. The developed SEDI was applied to study areas, 56 villages in 2 subdivision areas of county, located on county of Keumsan. Applicability of the index system, database system should be developed with the surveying method of data in village level.