• Applied Chemistry
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• v.15 no.1
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• pp.29-32
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• 2011

Surfactant enhanced fluorescence (FL) of europium-salicylic acid (SA) complex has been studied. It was observed that weak FL of Eu(III) at the wavelength of 589 nm and 612 nm was found to be enhanced after addition of salicylic acid and cetyltrimethylammonium bromide (CTAB) surfactant upon excitation at 395 nm. Under optimized condition, FL intensity of Eu(III) at 612 nm responded linearly with the concentration of SA in the range of 5.5×10^-9 to 1.5×10^-6 M of SA. The detection limit was calculated from the calibration curve(3Sb/m) as 9.27×10^-9 M.

• Applied Microscopy
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• v.6 no.1
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• pp.9-20
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• 1976

The present study was performed to clarify the histochemical compositions and fine structure of the mucus secreting cells in the gastrointestinal mucosa of normal mice. The mucus cells in the surface epithelium of stomach body had neutral mucin and some quantity of weak acid mucin. And the mucus cells in gastric pits and mucus neck cells had neutral mucin. The goblet cells in villial epithelium of small intestine contain strong acid sulfated mucin as their main content and a little of neutral mucopolysaccharide. However, the goblet cells in intestinal glands-Liberkuhn crypt were confirmed to contain non-sulfated weak acid mucin. The goblet cells in the surface epithelium of colon had the same component as the small intestine did. But the cells in the crypts of colon contained neutral and weak acid mucin as their main contents. The majority of secretory granules of the surface epithelial cells of the stomach body had high electron density, and some granules with low electron density appeared too. While the mucin granules in the mucus neck cells were low in its electron density, and some of those granules were frequently found to have dense core in them. Secretory granules in goblet cells of small and large intestines had low electron density. The mode of secretion in mucin-containing cells in gastro-intestinal tract was found to be merocrine.

• Journal of Soil and Groundwater Environment
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• v.18 no.7
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• pp.25-31
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• 2013

Hydrogen peroxide takes much of the cost for Fenton reaction applied for treatment of organic contaminants. Therefore, the effective use of hydrogen peroxide makes the technology more cost effective. The effective use of hydrogen peroxide is especially needed in the soil and groundwater remediation where complete mixing is not possible and it takes a long time for reactive species to transport to the fixed target compounds. Stabilization ability for hydrogen peroxide of malonic acid was evaluated in Fenton and Fenton-like reactions in this study. Malonic acid contributes on the stabilization of hydrogen peroxide by weak interaction between iron and the stabilizer and inhibiting the catalytic role of iron. The stabilization effect increased as the solution pH decrease below the $pK_{a1}$. The stabilization effect increased as the concentration of malonic acid increased and the effect was maximized at the malonic acid concentration of about ten times higher than the iron concentration. The model organic contaminant was successfully oxidized in the presence of the stabilizer but the degradation rate was slower than the system without the stabilizer. The stabilization effect was also proved in a Fenton-like reaction where magnetite and hematite were used instead of soluble iron species.

• Natural Product Sciences
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• v.15 no.4
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• pp.234-240
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• 2009

Phytochemical investigation of the MeOH extract of the aerial parts of Bistorta manshuriensis resulted in the isolation of two cerebrosides, two lactams, six phenolic compounds and seven flavonoids. Their chemical structures were characterized by spectroscopic methods to be pinelloside (1), soyacerebroside I (2), pterolactam (3), 5-hydroxypyrrolidine-2-one (4), vanillic acid (5), caffeic acid methyl ester (6), protocatechuic acid (7), caffeic acid (8), 3,5-di-O-caffeoyl quinic acid methyl ester (9), chlorogenic acid methyl ester (10), avicularin (11), afzelin (12), quercetin (13), isoorientin (14), quercetin 3-O-${\beta}$-D-glucoside (15), quercitrin (16), and luteolin (17). The isolated compounds (1 - 4, 7, 12, 14) were isolated for the first time from this plant source and the compounds 1 - 4, 9 and 10 were first reported from the genus Bistorta. Compound 17 exhibited moderate cytotoxicity and compound 6 exhibited weak cytotoxicity against four human cancer cell lines in vitro using an SRB bioassay.

• Korean Journal of Materials Research
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• v.27 no.2
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• pp.113-118
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• 2017

Natural and expandable graphites were chemically treated in acidic aqueous solutions such as acetic acid or mixtures of acetic acid and nitric acid. Structures and thermal conductivities of the as-treated graphites were characterized in detail. Both graphites were significantly oxidized in the mixed acidic solution of $H_2SO_4$ and $HNO_3$, which condition was generally used for the oxidation of carbon nanotubes. This considerable oxidation of graphites caused a depression of their thermal conductivity. The structural characteristics, obtained by XRD and XPS, show that the graphites treated in the relatively weak acidic conditions (acetic acid or mixture of acetic acid and nitric acid) were quite similar to the untreated graphites. However, the thermal conductivities of both acidic-treated graphites were remarkably increased.

• The Korean Journal of Food And Nutrition
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• v.5 no.2
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• pp.69-76
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• 1992

Sogokju, an old Korean rice wine, was brewed in laboratory scale in February, 1978, and the changes in chemical component and microorganisms in wine mash were investigated during brewing. In the course of first-mash brewing, lactic acid bacteria became the most predominant microflora in 3 days of fermentation lowering the pH of mash to 4.2. But at 7 days, the most predominant microorganism was changed from lactic acid bacteria to least, pH reached 3.6, and the saccharogenic activity of mash was reduced from initial 10 to 3.6. During second-mash brewing, remarkable changes did not occurred in pH and acidity, maintaining 3.5∼3.7 of pH and 8.0∼8.8 of acidity. Ethanol fermentation was proceeded vigorously until 20 days of fermentation, but it reached stationary state with 18.5% ethanol after 40 days, leaving reducing sugar unfermented in mash. Even if saccharogenic activity continued all during fermentation, it was thought to be too weak. The final product of Sogokju filterate, fermented for 60 day, contained 18.8% ethanol, 5.0% reducing sugar,0.4:1 total acid, 0.057% volatile acid, 0.206% amino acid and 7.3% extract. In sensory test, Sogokju scored good marks with similar level to commercial Bupju or Chungju. It had pale yellow color, gentle Nuluk-flavor and acid taste just a little strong.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.67-73
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• 1995

Effects of tocopherols and $\beta$-carotene on the oxidation of the solid model system of a free fatty acid mixture (64.5% of linolic acid ; 26.4% of oleic acid ; 5.0% of palmitic acid) with tocopherols and $\beta$-carotene were studied. $\alpha$-tocopherol revealed an antioxidant activity at the concentration below 0.05%, however, it showed a prooxidant activity when the concentration was higher than 0.05%. The antioxidant activity of ${\gamma}$ -tocopherol was not affected by the concentrations in the range of 0.01~0.10% in the model and ${\gamma}$-tocopherol showed higher antioxidant activity than that of $\alpha$-tocopherol. It seemed that $\alpha$-tocopherol was unstable compared to ${\gamma}$-tocopherol during oxidation. $\beta$-carotene showed a weak antioxidative activity at the initial stage of this system while $\beta$-carotene showed a prooxidant activity in the presence of tocopherol. $\beta$ -carotene was highly susceptible to autoxidative degradation during oxidation.

• Natural Product Sciences
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• v.26 no.4
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• pp.345-350
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• 2020

In recent years, tyrosine kinases (TKs) have been the target to combat cancers, and most of the developed inhibitors are of synthetic origin. Natural compounds that have the properties as the TK's inhibitors are very limited. This paper described the isolation of a new dammarane triterpene from the tree bark of Sandoricum koetjape, along with three known related dammaranes from the damar resin of Shorea javanica, as well as their inhibitory properties against eight receptor TKs (RTKs: EGFR, HER2, HER4, IGF1R, InsR, KDR, PDGFRα, and PDGFRβ). Based on the NMR and mass spectral data the new compound was identified as (12β,20S)-12,20-dihydroxy-3,4-seco-dammaran-4,24-dien-3-oic acid (12β-hydroxydammarenolic acid) (1), while the three known compounds were identified as (20S)-20-hydroxy-3,4-seco-dammaran-4,24-dien-3-oic acid (dammarenolic acid) (2), (3β,20S)-3,20-dihydroxydammaran-24-ene (3), and (20S)-3-oxo-20-hydroxydammaran-24-ene (4). The tyrosine kinase assay of the four compounds resulted only 1 and 2 at concentration of 10 μM that had weak activity against EGFR and InsR, with their % inhibitory were 30%, 27% (1), 45%, and 32% (2), respectively. The results suggested that the presence of a linear carboxylic acid group in both compounds could be of significance to the inhibitory properties against the two RTKs.

• Korean Journal of Pharmacognosy
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• v.43 no.2
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• pp.107-121
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• 2012

Twenty-five compounds were isolated from the methanolic extract of Geum japonicum (Rosaceae), and their structures were identified as eleven triterpenoids [ursolic acid 3-acetate (2), cecropiacic acid 3-methyl ester (3), pomolic acid 3-acetate (5), ursonic acid (6), ursolic acid (7), pomolic acid (8), corosolic acid (9), euscaphic acid (11), arjunic acid (16), tormentic acid (18), 23-hydroxytormentic acid (21)], two saponins [rosamultin (22) and kaji-ichigoside $F_1$ (23)], two megastigmanes [blumenol A (14) and (+)-dehydrovomifoliol (15)], three flavonoids [apigenin (13), isoquercitrin (17) and tiliroside (24)], two ellagic acid derivatives [3,3'-di-O-methylellagic acid (12) and ducheside B (25)] and five others [eugenol (1), emodin (4), vanillic acid (10), gallic aldehyde (19), salidroside (20)]. The chemical structures of these compounds were identified on the basis of spectroscopic methods and comparison with literature values. This is the first report of the eleven compounds, 2~6, 10, 15, 16, 20, 23, and 25 from the genus Geum, as well as the first report of apigenin (13) and 3,3'-di-O-methylellagic acid (12) from G. japonicum. The antioxidant properties of 22 isolates (1~11, 14, 16~25) were evaluated by the intracellular reactive oxygen species (ROS) radical scavenging using 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA) assay. Among them, isoquercitrin (17) showed significant scavenging activity, and gallic aldehyde (19) and ducheside B (25) showed weak scavenging activity.

• Korean Journal of Community Nutrition
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• v.8 no.2
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• pp.192-201
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• 2003

The purposes of this research were to assess dietary fatty acid patterns and to elucidate the relationship between the serum cholesterol levels and dietary fatty acid patterns, plasma fatty acid compositions, BMI (body mass index), and other lipid profile. The subjects were 151 adults aged 23 to 80 years, selected from the Outpatient Clinic and Cardiova-scular Department of the Seoul Municipal Hospital. Dietary data were obtained using three day food records. Sixteen dietary fatty acids were analyzed using Korean and US nutrient databases. The subjects were divided into three serum cholesterol levels: desirable (< 200 mg/dl, N = 44), borderline-risk ($\geq$ 200 - < 240 mg/dl, N = 35), and high-risk ($\geq$ 240 mg/dl, N = 72) groups. The high-risk group had higher BMI, waist, and waist to hip ratio (WHR) than the desirable and borderline-risk groups. Serum concentrations of triglyceride, LDL cholesterol and LDL/HDL cholesterol ratio were significantly higher in the high-risk group as compared to those in the other two groups. The serum cholesterol levels were highly correlated with BMI (r = 0.435), triglyceride (r = 0.425) and LDL/HDL cholesterol (r = 0.870) ratio. The highest fatty acid intake was from oleic acid (33 - 34% of total fatty acid intakes), which was followed by linoleic acid (27%), palmitic acid (19%), and stearic acid (7%). There was no correlation between the serum cholesterol levels and the dietary fatty acid intakes, polyunsaturateumonounsaturateusaturated fatty acids (P/M/S) and $\omega$6/$\omega$3 ratios. The correlation between plasma fatty acids such as myristic acid, oleic acid, linoleic acid, and docosahexaenoic acid and serum cholesterol levels was also weak. (Korean J Community Nutrition 8(2) : 192~201, 2003)