• 한국식품위생안전성학회지
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• 제1권2호
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• pp.171-176
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• 1986

충청북도 청원군 9개면에서 수집한 자가탁주 시료와 청주지역 시장에서 수집한 국내산 땅콩버터중의 aflatoxins 검색 결과 다음의 결론을 얻었다. 1. 자가탁주 시료에서는 78% 이상의 지역 시료에서 aflatoxin B1이 검출되었으며 평균 0.36 ppb, 최고 1.2 ppb까지 검출되었다. 2. 국내산 땅콩버터 시료에서는 aflatoxin류가 검출되지 않았다. 3. Sep-Pak silica cartridge에 의한 정제법은 기존의 column chromatography 정제법보다 회수율, 시간, 시약 등에서 훨씬 더 효율적이었다.

• 센서학회지
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• 제32권1호
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• pp.39-43
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• 2023

Microscale thermophysical property measurements of liquids have been developed considering the increasing interest in the thermal management of cooling systems and energy storage/transportation systems. To accurately predict the heat transfer performance, information on the thermal conductivity, heat capacity, and density is required. However, a simultaneous analysis of the thermophysical properties of small-volume liquids has rarely been considered. Recently, we proposed a new methodology to simultaneously analyze the aforementioned three intrinsic properties using heater-integrated fluidic resonators (HFRs) in an atmospheric pressure environment comprising a microchannel, resistive heater/thermometer, and mechanical resonator. Typically, the thermal conductivity and volumetric heat capacity are measured based on a temperature response resulting from heating using a resistive thermometer, and the specific heat capacity can be obtained from the volumetric heat capacity by using a resonance densitometer. In this study, we analyze methods to improve the thermophysical property measurement performance using HFRs, focusing on the effect of the ambience around the sensor. The analytical method is validated using a numerical analysis, whose results agree well with preliminary experimental results. In a vacuum environment, the thermal conductivity measurement performance is enhanced, except for the thermal conductivity range of most gases, and the sensitivity of the specific heat capacity measurement is enhanced owing to an increase in the time constant.

• Current Optics and Photonics
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• 제7권5호
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• pp.569-573
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• 2023

We utilized terahertz time-domain spectroscopy (THz-TDS) to measure the thickness and electrical properties of nickel-chromium (Ni-Cr) films. This technique not only aligns well with traditional methods, such as haze-meter and transmission-densitometer measurements, but it also reveals the electrical properties and thickness of films down to a few tens of nanometers. The complex conductivity of the Ni-Cr thin films was extracted using the Tinkham formula. The experimental values closely aligned with the Drude model, indicating the reliability of our Ni-Cr film's electrical and optical constants. The thickness of Ni-Cr was estimated using the complex conductivity. These findings emphasize the potential of THz-TDS in quality control of metallic nanofilms, pointing toward an efficient and nondestructive test (NDT) for such analyses.

• Journal of the Korean Wood Science and Technology
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• 제36권6호
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• pp.13-22
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• 2008

보드의 기계적 성질에 영향을 미치는 공극에 대하여 공극을 두가지로 분류하고 밀도에 따른 오에스비의 내부 공극구조의 특성에 대하여 살펴보고자 하였다. 스트랜드보드의 내부공극을 X-ray 단층촬영기로 측정하고 이미지분석 소프트웨어를 사용하여 밀도에 따른 공극의 분포와 공극의 함유량을 조사하였다. 측정 전에 보드의 밀도를 밀도측정기와 전건법으로 측정하였으며 이 두 방법에 의해 측정된 결과는 아주 높은 상관관계를 보여주었다. X-ray를 서로 다른 배율로 조사하여 획득한 이미지를 바탕으로 분석한 결과, 저해상도에서는 스트랜드간의 공극(macro-void)의 측정이 가능하나 스트랜드내의 미세공극(micro-void)은 이미지획득이 불가능하였다. 중해상도에서는 두가지 형태 모두의 이미지 획득이 가능하였고, 고해상도에서는 대부분의 미세공극 이미지의 획득이 가능하였다. 저배율을 채택하여 스트랜드간의 공극을 측정하고 스트랜드내의 미세공극은 관련식을 이용하여 추정하였다. 이를 통해 보드내부에 존재하는 스트랜드간의 공극분포를 파악할 수 있었으며 그 공극의 함유비율을 정확하게 산정할 수 있었다.

• 한국약용작물학회지
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• 제13권3호
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• pp.101-104
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• 2005

2003년 6, 8월에 지리산과 전남 담양군의 병풍산에서 자생하는 고추나물과 물레나물을 채집하여 TLC 분석을 하고, TLC-densitometry를 이용해 정량한 결과, 물레나물에서는 hypericin이 확인되지 않은 반면, 고추나물의 꽃봉오리와 잎에서는 다량의 hyepricin이 확인되었다. 그리고 지리산에 자생하는 고추나물보다 병풍산 고추나물의 hypericin함량이 더 높게 나타났고, 고도가 낮을수록 hypericin 함량이 높은 것으로 나타났다. 채집 시기별로 비교했을 때, 병풍산은 6월보다 7월에서 hypericin함량이 높게 나타났고, 지리산에서는 7월에 가장 진하게 보였다. St. John's wort와 고추나물을 비교하였을 때, 2.22 $mg/{\ell}$ hypericin을 함유한 St. John's wort 보다 3.2 $mg/{\ell}$의 함량을 보이는 병풍산 고추나물에서 hypericin함량이 더 높은 것으로 확인되었다.

• 치과방사선
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• 제17권1호
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• pp.107-120
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• 1987

The purpose of this study was three-fold: to reexamine whether periapical and central lesions can be detected on the radiograph when they are in the cancellous bone, to investigate regianal differences in radiograph visualization of the lesion, and to. compare the interpretation of radiagraphs by densitometric analysis with the visual interpretation af the same radiographs. Forty-nine apical lesions and eighty-two central lesions were made in 8 mandibles and radiographed serially while being enlarged and deepened. All radiagraphs were evaluated by three dental radiologists. Each lesion was scored of 3 to 0, based on the radiographic appearances. Special radiographs of 15 apical and central lesions were analysed by densitometer and the results were compared with the scores which were previously assigned by three examiners. From this study the following conclusians could be drawn; 1. Experimental lesions confined to cancellous bone were detected an the radiagraphs in 41.3% of the cases. 2. Visualization of periapical lesions in cancellous bone was more apparent than that of central lesions in cancellous bone. 3. Visualization of the periapical lesions confined to. cancellous bane was highest in molar teeth, and detection of the central lesions in alveolar portion was easier than those in lower portion of mandibular body area. 4. It was possible to detect the experimental lesions without cortical plate involvement in 78.6% of the all lesions. 5. Densitometric analysis of radiographs could reproducibly distinguish bone changes, especially of central lesions in cancellous bone.

• 치과방사선
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• 제17권1호
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• pp.197-207
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• 1987

This study was undertaken to investigate the relationships between film and processing solution at different processing temperatures. Three kinds of periapical film were used for this study. They included EP-2l film, DF-58, and A film Each film was processed by automatic film processor with RD-Ⅲ X-dol 90, and A processing solutions at 68° 74° 80° 86° and 92°F. Film density was measured with the densitometer, and base plus fog density, film relative speed, film contrast, and subject contrast were evaluated. The following results were obtained; 1. As the processing temperature was increased, base plus density was increased. Inadequate base plus fog densities were obtained with three films in combination with three processing solutions at 92°F. 2. Lowest base plus fog densities were obtained with A film, followed in ascending order by EP-21, and DF-58 film in combination with A or RD-Ⅲ processing solutions. The sequence of base plus fog densities was in ascending order by EP-21, A, and DF-58 film in combination with X-dol 90 processing solution. 3. The sequence of film relative speed values was in ascending order of EP-21, A, and DF-58 film in combination with A and RD-Ⅲ processing solutions, respectively. 4. As the processing temperature was increased, film contrast values was increased. The sequence of film contrast values was in descending order solution. The sequence of film contrast values was in descending order of EP-2l, DF-58, and A film in combination with RD-Ⅲ, X-dol 90 processing solution at 80°F. 5. As the processing temperature was increased, subject contrast was increased. The sequence of subject contrast was in descending order of A, X-dol 90, and RD-Ⅲ processing solution in combination with three films at 80°F. The sequence of subject contrast was in descending order of EP-21, A, and DF-58 film in combination with A processing solution at different processing temperatures.

• Journal of Periodontal and Implant Science
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• 제43권1호
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• pp.24-29
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• 2013

Purpose: Matrix metalloproteinases (MMPs) are capable of degrading extracellular matrix, and they are inducible enzymes depending on an inflammatory environment such as periodontitis and bacterial infection in periodontal tissue. Gingival inflammation has been postulated to be correlated with the production of MMP-2 and MMP-9. The objective of this study was to quantify the expression and activity of MMP-9 and -2, and to determine the correlation between activity and expression of these MMPs in human gingival tissues with periodontitis. Methods: The gingival tissues of 13 patients were homogenized in $500{\mu}L$ of phosphate buffered saline with a protease inhibitor cocktail. The expression and activity of MMP-2 and -9 were measured by enzyme-linked immunosorbent assay and Western blot analysis, and quantified by a densitometer. For the correlation line, statistical analysis was performed using the Systat software package. Results: MMP-9 was highly expressed in all gingival tissue samples, whereas MMP-2 was underexpressed compared with MMP-9. MMP-9 activity increased together with the MMP-9 expression level, with a positive correlation (r=0.793, P=0.01). The correlation was not observed in MMP-2. Conclusions: The expression of MMP-2 and -9 might contribute to periodontal physiological and pathological processes, and the degree of MMP-9 expression and activity are predictive indicators relevant to the progression of periodontitis.

• 한국식품과학회지
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• 제36권4호
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• pp.558-562
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• 2004

TLC를 이용하여 간편하고 신속하게 정량적인 이소플라본의 분석을 수행할 수 있는 조건을 개발하였다. 전개 용매로는 chloroform : methanol : water : acetic acid를 각각 60 : 30 : 10 : 0.5의 비율로 하였을 때 최적의 분리를 보였으며, 정량적인 분석은 UV에서의 흡광도를 densitometer를 사용하여 spot의 intensity를 계산함으로 가능하였다. HPLC분석법과의 비교 결과 $0.15-1.80{\mu}g/{\mu}L$의 범위에서 이소플라본을 정량적으로 분석할 수가 있었다. 또한 TLC를 이용하여 일반 콩과 식물에 포함되어 있는 이소플라본의 함량 측정 결과 HPLC의 결과와 상당히 근소한 값으로 일치하여 TLC방법으로 간편하고 빠르게 정량적인 측정이 가능함을 확인하였다.

• 생약학회지
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• 제38권2호통권149호
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• pp.187-191
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• 2007

The extraction yield of the methanolic extracts and 19${\alpha}$-hydroxyursane-type triterpenoid (19${\alpha}$-HUT) fraction were investigated in the unripe and ripe fruits and the leaves of the four Rubus plants (Rubus coreanus, R. crataegifolius, R. phoenicolasius, R. pungens var. oldhami) to develop the biomaterial 19${\alpha}$-HUT mixture as functional foods. Thin layer chromatogaphy-Densitometer (TLC-DM) was used to analyze the individual quantity of 19${\alpha}$-HUTs using standard compounds (euscaphic acid, tormentic acid, 23-hydroxytormentic acid, kaji-ichigoside F$_1$, rosamultin, niga-ichigoside F$_1$). The content of methanolic extract of the fruits were higher in the ripe stage than in the unripe stage whereas the content of 19${\alpha}$-HUT mixture varied with each Rubus species. The Rubus plants containing the highest amount of 19${\alpha}$-HUTs in the leaves were R. coreanus, R. phoenicolasius and R. pungens var. oldhami while only R. cratagefolius showed the highest content in the ripe fruits. The mean of total genin content of 19${\alpha}$-HUTs was 0.94 mg/g; that of the glycosides was 0.60 mg/g. The genin quantity was found in the order of 23-hydroxytormentic acid> euscaphic acid> tormentic acid; the glycoside was observed in the order of niga-ichig-oside F$_1$> kaji-ichigoside F$_1$> rosmaultin, by which the biosynthetic pathway of 23-hydroxytormentic acid and its glucoside niga-ichigoside F$_1$ via the intermediates tormentic acid and/or rosamultin was presumed. It is also suggested that the ripe fruits of R. crataegifolius will be desirable to use as functional foods rather than unripe fruits.