• 분석과학
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• 제10권4호
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• pp.300-306
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• 1997

직류전압강하법을 이용한 균열길이 측정방법은 입출력 도선의 위치 및 보정방법에 큰 영향을 받는다. 본 실험에서는 CT 시편을 실제 시편보다 9배 크기로 제작하여, 입출력 도선의 위치, 열 유도 EMF 및 기준전압의 위치가 기존의 보정곡선에 미치는 영향을 연구하였다. 연구 결과 입력전류 도선의 위치가 하중선에 위치할 때, Hicks-Pickard 관계식이 매우 정확하게 a/W와 V/Vo간의 관계를 나타내었으며, 이 때 Vo값을 a/W=0.241에서 측정 또는 계산된 값을 사용하고, 열유도 EMF를 보정함으로써 더욱 정확성을 향상시킬 수 있음을 알았다. 또한 입력도선이 하중선에 위치할 때 기준전압을 CT 시편에서 일반적으로 사용되는 위치인 시편 끝 하단에서 측정할 경우, 기준전압으로 보정한 전압값은 매우 큰 오차를 나타내었다.

• 대한임상검사과학회지
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• 제47권4호
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• pp.306-312
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• 2015

알러지 반응이 일어나면 histamine이 방출되기 때문에 histamine을 정량 측정함으로써 유발된 알러지의 정도를 확인 할 수 있다. 일반적으로는 항원-항체반응으로 microplate reader를 이용하여 흡광도를 측정하여 정량 한다. 본 연구에서는 histamine 방출량을 측정함에 있어서 일반적인 항원-항체반응과 분석 화학적인 방법으로 HPLC-MS를 이용한 방법을 비교하였다. 세포주는 RBL-2H3를 사용하였고, C48/80으로 자극시켜 알러지를 유발하였다. 유발된 알러지는 ${\beta}$-hexosaminidase의 측정으로 탈 과립을 확인하였으며 실험의 정당성을 위하여 세포독성 능을 확인하였다. Histamine 정량에서 항원-항체반응에 의한 측정의 정량한계는 10.257 ppm이었고, HPLC-MS에 의한 정량한계는 0.020 ppm으로 현저한 차이를 보였다. 알러지 활성 및 항 알러지 실험에 있어서 histamine의 측정은 HPLC-MS를 이용한 분석이 더 정밀하고 정확한 실험인 것을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제18권9호
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• pp.1550-1554
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• 2008

A hydrogen sulfide $(H_2S)$ detecting tube was developed for the quantitative determination of $H_2S$ produced by yeast during laboratory scale wine fermentations. The detecting tube consisted of a small transparent plastic tube packed with an $H_2S$-sensitive color-indicating medium. The packed medium changed color, with the color change progressing upward from the bottom of the tube, upon exposure to $H_2S$ produced by yeast during fermentation. A calibration study using a standard $H_2S$ gas showed that the length of the portion that darkened was directly related to the quantity of $H_2S$ (${\mu}g$) with a high correlation coefficient ($r^2$=0.9997). The reproducibility of the $H_2S$ detecting tubes was determined with five repetitive measurements using a standard $H_2S$ solution [5.6${\mu}g$/200 ml (28 ppb)], which resulted in a coefficient of variation of 3.6% at this level of $H_2S$. With the sulfide detecting tubes, the production of $H_2S$ was continuously monitored and quantified from laboratory scale wine fermentations with different yeast strains and with the addition of different levels of elemental sulfur to the grape juice. This sulfide detecting tube technology may allow winemakers to quantitatively measure $H_2S$ produced under different fermentation conditions, which will eventually lead winemakers to better understand the specific factors and conditions for the excessive production of $H_2S$ during wine fermentation in a large production scale.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권5호
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• pp.561-565
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• 2010

센서 네트워크의 수명을 향상 시키기 위해 모바일 싱크 기술을 이용하는 다양한 기법이 연구되고 있다. 모바일 싱크를 이용한 대표적인 연구로 트랙기반 모바일 싱크 운용 기법과 앵커 포인트기반 모바일 싱크 운용 기법이 있다. 이러한 기법들은 질의 발생 위치, 데이터 중요도 등과 같은 네트워크 환경을 고려하지 않은 고정적인 경로 기반으로 하여 QoS(Quality of Service)를 감소시키고, 경로 인근에 전송 핫스팟을 야기시켜 네트워크 수명을 감소시킨다. 본 논문에서는 기존 기법들의 문제점을 해결하는 모바일 싱크 운용 기법을 제안한다. 제안하는 기법에서는 데이터의 중요도를 고려하여 모바일 싱크의 탐색 우선순위를 결정하여 QoS를 높이고, 모바일 특성을 최대한 활용하여 라우팅 핫스팟을 최소화 시킨다. 성능평가 결과 기존 기법에 비해 평균 질의 응답시간을 감소시키고, 네트워크 수명이 연장됨을 보였다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권2호
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• pp.835-838
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• 2016

Background: Lung cancer remains one of the most common cancers in the world, both in terms of new cases (about 13% of total per year) and deaths (nearly one cancer death in five), because of the high case fatality. Errors in lung cancer type or malignant growth determination lead to degraded treatment efficacy, because anticancer strategy depends on tumor morphology. Materials and Methods: We have made an attempt to evaluate effectiveness of machine learning algorithms in the task of lung cancer classification based on gene expression levels. We processed four publicly available data sets. The Dana-Farber Cancer Institute data set contains 203 samples and the task was to classify four cancer types and sound tissue samples. With the University of Michigan data set of 96 samples, the task was to execute a binary classification of adenocarcinoma and non-neoplastic tissues. The University of Toronto data set contains 39 samples and the task was to detect recurrence, while with the Brigham and Women's Hospital data set of 181 samples it was to make a binary classification of malignant pleural mesothelioma and adenocarcinoma. We used the k-nearest neighbor algorithm (k=1, k=5, k=10), naive Bayes classifier with assumption of both a normal distribution of attributes and a distribution through histograms, support vector machine and C4.5 decision tree. Effectiveness of machine learning algorithms was evaluated with the Matthews correlation coefficient. Results: The support vector machine method showed best results among data sets from the Dana-Farber Cancer Institute and Brigham and Women's Hospital. All algorithms with the exception of the C4.5 decision tree showed maximum potential effectiveness in the University of Michigan data set. However, the C4.5 decision tree showed best results for the University of Toronto data set. Conclusions: Machine learning algorithms can be used for lung cancer morphology classification and similar tasks based on gene expression level evaluation.

• The Korean Journal of Physiology
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• 제28권1호
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• pp.71-77
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• 1994

In the animal model of acute respiratory distress syndrome (ARDS) induced by N-nitroso-N-methylurethane (NNNMU) the secretory activity of alveolar type H cells during acute alveolar injury was investigated by determining phospholipid and pulmonary surfactant associated proteins in crude surfactant. The mechanism of the secretory change was studied by determination of DNA and RNA levels in the lung tissue. After induction of acute alveolar injury with NNNMU, pulmonary hemorrhage, atelectasis and gross hypertrophy were observed. Seven days after NNNMU treatment the level of total DNA in lung homogenate was increased markedly indicating that a hypertrophy was induced by cellular proliferation. Although the total DNA level increased, the RNA/DNA ratio was gradually decreased after NNNMU treatment. Seven days after NNNMU treatment the RNA/DNA ratio returned to the normal control level. During the acute alveolar injury, phospholipid and surfactant associated proteins were reduced significantly as compared with the control, implying that the secretory activity of alveolar type II cells was altered during acute alveolar injury induced by NNNMU. The protein content in crude surfactant during peak injury(7 days after NNNMU) was decreased significantly but phospholipid/protein ratios were identical in both control and NNNMU treatment groups. SDS-PAGE of proteins in crude pulmonary surfactant showed a decrease in major surfactant associated protein(M.W. 38,000) during acute alveolar injury. The present study may suggest that while alveolar type H cells proliferate markedly, transcription of alveolar type ll cell gene was inhibited by an unknown mechanism such as DNA methylation induced by NNNMU. Such an inhibition of transcriptional activity is thought to be associated with the decreased secretory activity of alveolar type ll cells, which may lead to pulmonary atelectasis and edema during the acute alveolar injury.

• Imaging Science in Dentistry
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• 제30권4호
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• pp.243-248
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• 2000

Purpose: The aim of this study was to determine the relative radiopacities of cavity lining materials (Resin-modified Glass Ionomer cement, Compomer and Plowable resin) for posterior composite resin restoration. Material & Methods: Resin-modified glass ionomer cement (Fuji II LC, Vitrebond/sup TM/), Compomers (Dyract /sup (R)/ Compoglass, F2,000, Dyract/sup (R)/ flow Compoglass Flow) and Flowable resins (Tetric/sup (R)/ flow, Aeliteflo/sup TM/ Revolution/sup TM/) were used. Five specimens of 5 mm in diameter and 2 mm thick were fabricated with each material. Human molars were horizontally sectioned 2 mm thick to include both enamel and dentin. The radiopacities of enamel, dentin, cavity lining materials, aluminum step wedge were obtainded from conventional radiograph and NIH image program. Results: All the tested lining materials showed levels of radiopacity the same as or greater than that of dentin. All compomer tested (Dyract, Compoglass, F2,000, Dyract flow, Compoglass Flow) and Vitrebond/sup TM/, Tetric/sup (R)/ flow were more radiopaque than enamel. The radiopacities of Fuji II LC and Revolution/sup TM/ were between enamel and dentin and resin-modified glass ionomer cement, Compomer and Tetric/sup (R)/ flow were greater than those of Revolution/sup TM/, Aeliteflo/sup TM/ or dentin. The level of radiopacity of the tested materials was variable; those with low radiopacity should be avoided in class II restorations, where a clear determination of recurrent caries by the examining clinician could be compromised. Conclusion: Clinician should be able to distinguish these cavity lining materials radiographically from recurrent decay, voids, gaps, or other defects that lead to clinical failure. Utilization of materials ranked more radiopaque than enamel would enable clinicians to distinguish the lining material from tooth structure.

• 대한화학회지
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• 제41권6호
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• pp.292-298
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• 1997

유도코일을 5회 감고, 외측 석영관 길이를 일반적인 ICP(Inductively Coupled Plasma) 토오치에서 보다 50 mm 더 길게 제작한 수평형 ICP 방출원을 제작한 후, ICP 방출분광분석기를 구성하였다. 신호대 잡음비 및 바탕선의 세기를 고주파 출력, 시료 유량, 알곤가스 유량 그리고 차단가스 유량변화에 대하여 측정하고 최적조건을 구했다. 이들 조건에서,수직형 플라스마와 비교하여 분광분석학적으로 비슷한 정도의 특징을 가진 바탕선 스펙트럼을 파장범위 200~500 nm에서 얻었다. 납(II), 220.35 nm의 방출선에서 검출한계가 11 ppb로 산출되었으며, 수직형과 비교하여 약 5배 낮은 값을 보였다.

• 한국지반공학회논문집
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• 제18권2호
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• pp.87-96
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• 2002

자가굴착식 프레셔미터를 이용한 변형률 유지 시험은 점성토 지반의 수평방향 압밀계수를 추정하는데 있어 효과적으로 사용되고 있다. Clarke등(1979)이 제시한 일반적인 해석 방법은 여러 가지 단순화한 가정으로 인해 압밀계수산정에 문제점을 내포하고 있다. 따라서, 본 논문에서는 실제 시험 과정 및 조건들을 최대한 반영하기 위하여 프레셔미터 시험기의 유한한 길이, 계파시의 부분배수, 소산시험 시작시의 공동 변형률 등의 여러 가지 해석 조건들이 초기 과잉간극수압의 분포 및 소산 거동에 미치는 영향을 고려한 유한요소해석을 수행하였다. 그 결과, 수평방향 압밀계수를 추정하는데 필요한 50% 압밀도에서의 시간계수를 제안하였고, 이를 국내 2개 현장에서 수행한 변형률 유지시험에 적용하여 압밀계수를 산정하고, 다른 현장 시험 및 실내시험 결과와 비교.분석하여 그 적용성을 확인하였다.

• KSBB Journal
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• 제28권5호
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• pp.319-326
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• 2013

This study was carried out to investigate the in vitro and in vivo moisturizing properties and percutaneous absorption of PEG-impregnated Aloe vera gel. The PEG-i-Aloe gel was obtained from dewatering and impregnation by soaking (DIS) of Aloe vera leaf slice. The moisturizing property of the obtained sample was evaluated by moisture determination using gravimetric method in desiccator under different RH% and by water sorption-desorption test on human skin. The transdermal penetration characteristics of PEG-i-Aloe gel was investigated by Franz diffusion cell in vitro transdermal absorption method. PEG-i-Aloe gel had high moisture retention ability and could significantly lead the enhancing skin hydration status as well as reducing the skin water loss due to the film formation as a skin barrier. The skin penetration rate of PEGi- Aloe gel at steady state was 9.76 ${\mu}g/(h{\cdot}cm^2)$ and the quantity of the transdermal absorption was 144 ${\mu}g/cm^2$ in 9 hr. The penetration mechanism was well fitted with Higuchi model ($R^2$ = 0.974-0.994). The results show that PEG-i-Aloe gel has the significant moisturizing effect and strong penetration of the animal skin. It could be used as the moisturizing additive in cosmetic skin products.