• Journal of Food Hygiene and Safety
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• v.1 no.2
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• pp.171-176
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• 1986

ABSTRACT-In order to detect the aflatoxins in home-made Takju and peanut butter, the samples were collected in Chungbuk region and cleaned up Sep-pak silica cartridge. Aflatoxins were detected by thin layer chromatographic and high performance liquid chromatographic behavior. Determination was carried out by thin layer densitometer. The results were as follows; 1. Aflatoxin B, was detected in 78% of the home-made Takju, and the highest concentration was 1.2 ppb and average 0.36 ppb. 2. Aflatoxins were not detected in any peanut butter smaples. 3. Clean-up method by Sep-pak silica cartridge was more efficient and economical than column chromatography of AOAC method.method.

• Journal of Sensor Science and Technology
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• v.32 no.1
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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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• v.7 no.5
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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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• v.36 no.6
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• pp.13-22
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• 2008

Internal voids affecting the mechanical properties of wood composite were classified into two catagories and characteristics of voids were examined according to density variation of strandboard. The void distribution and content of strandboard according to board density were measured by X-ray computed tomography system and analized using image processing software. Prior to investigation, the densities of strandboard were measured by densitometer and the results were showed high correlation with conventional oven drying method. Based on the image analysis conducted on captured images by X-ray tomography, low resolution can be used to capture the macro-voids (between strand) but not the micro-voids (within strands). Intermediate resolution can be used to capture both the macro and the micro-voids and high resolution can be successfully used to capture the majority of the micro-voids. The content of macro-void was measured and content of micro-void was computed by corresponding related equation. The macro-void distribution can be successfully understood and void content can be correctly estimated through the results.

• Korean Journal of Medicinal Crop Science
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• v.13 no.3
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• pp.101-104
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• 2005

To explore the Korea native plants to substitute for St. John's wort, which produce hypericin that use commercially for the treatment of mild to moderate depression, hypericin contents of Hypericum erectum and H. ascyron collected in two mountain of Korea were examined. From TLC and TLC-densitometer analysis of hypericin contents and biosynthetic pattern, hypericin was detected in flower and leaf of H. erectum, but not in all organs of H. ascyron. The hypericin content of H. erectum grown 200 m high hill in Mt. Byoung-pung was higher than that of Mt. Ji-ri 500 m and 1300 m high hill. When the seasonal variation of hypericin contents in H. erectum leaf collected from two regions was investigated, leaf collected from both regions on July was higher than other seasons.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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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.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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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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• v.43 no.1
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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.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.558-562
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• 2004

Conditions for rapid quantification of isoflavones were studied. Rapid and clear separation of isoflavones (genistin and daidzin) was obtained using solvent system of chloroform : methanol : water : acetic acid (60 : 30 : 10 : 0.5, v/v/v/v). Quantification of each isoflavone separated by TLC was conducted by densitometry analysis. Genistin and daidzin were quantified in $0.15-1.80\;{\mu}g/{\mu}L$ range with 99% confidence. Concentrations of isoflavones in soybeans and kudzu roots originated from Korea were determined, and validity of TLC method for quantification of isoflavones was confirmed by comparison with HPLC analysis.

• Korean Journal of Pharmacognosy
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• v.38 no.2 s.149
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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.