• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.723-735
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• 1998

Background : Vitamin C has been reported to have a role in the decrease of airway hyperresponsiveness in animal models. This data is based on some metabolic actions of vitamin C, such as promotion of histamine degradation, producing more $PGE_2$ than $PGF_{2\alpha}$ in cyclooxygenase pathway, decrease of smooth muscle contraction, and acting as reducing agent of oxidant. It has been also known that heavy smokers have lower blood levels of vitamin C than nonsmokers and this deficiency in heavy smokers have been explained by several mechanisms, such as increased oxidation by oxidants and free radicals, increased biosynthesis of catecholamine and serotonin released by nicotine, and inadequate dietary intake. In this study, We attempted to assess effect of vitamin C on bronchial hyperresponsiveness in heavy smokers who have bronchial hyperresponsiveness and role of vitamin C on bronchial hyperresponsiveness. Method: To assess acute effect of vitamin C on airway hyperresponsiveness, blood sample for vitamin C level and spirometry, methacholine challenge test were done in 17 smokers and 8 nonsmokers, and one hour after oral administration of vitamin C 3 g, blood sample for vitamin C level and spirometry, methacholine challenge test were repeated. To assess chronic effect of vitamin C on airway hyperresponsiveness, after daily administration of vitamin C 1 g for one week in 17 smokers, blood sample for vitamin C level and spirometry, methacholine challenge test were done. To assess role of vitamin C, after oral administration of vitamin C 3 g plus indomethacin 100 mg in 12 of 15 smokers who were reactive to methacholine challenge test, spirometry and methacholine challenge test were done and after oral intake of indomethacin 100 mg in 12 smokers who were reactive to methacholine challenge test, spirometry and methacholine challenge test were repeated. Result: There were no significant differences in whole blood vitamin C levels between smokers($1.17{\pm}0.22$ mg/dL) and nonsmcikers($1.14{\pm}0.19$ mg/dL) (p>0.05). Fifteen of the 17 smokers(88.2%) were reactive to methacholine challenge test and 10 of the 15 smokers who were reactive to methacholine challenge test were less than 8 mg/dL in $PC_{20}FEV-2$, and 7 of the 8 nonsmokers(87.5%) were nonreactive to methacholine challenge test There were significant decrease in bronchial responsiveness after oral administration of vitamin C 3 g in 13 of the 15 smokers who were reactive to methacholine challenge test This significant decrease persisted with maintenance daily administration of 1 g for one week. $PC_{20}FEV-2$ were not correlated to vitamin C levels in smokers. After oral administration of indomethacin 100 mg, significant reduction of bronchial responsiveness that occured after oral administration of vitamin C 3 g in smokers were attenuated. Conclusion: Although there were no significant differences in whole blood vitamin C levels between smokers and nonsmokers. heavy smokers have significant increase in bronchial responsiveness than nonsmokers. This bronchial hyperresponsiveness of heavy smokers can be attenuated by vitamin C supplement. Disappearance of vitamin C effect by indomethacin supplement may suggest that vitamin C exert its effect via alteration of arachidonic acid metabolism.

• Journal of the Korean Chemical Society
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• v.46 no.1
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• pp.64-68
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• 2002

Photocatalytic treatment of aqueous cyanide was studied using both commercial and home-made $TiO_2$'s as catalysts. Among the catalysts, $TiO_2$ made from $Ti(OC_3H_7)_4$ as a precursor showed the highest activity for the degradation of cyanide exceeding a commercial catalyst of Degussa P25. The difference in activities of the catalysts was mainly related to the surface properties of the catalysts such as the ratio of acidic to basic hydroxyl groups. For the catalyst which showed the highest activity, partially reduced $TiO_2$ showed better activity than calcined one.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.65-68
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• 2000

To understand the antioxidative mechanism in plant cell cultures, we investigated the levels of antioxidant enzymes and low molecular antioxidants in 100 cell lines derived from different plant species. SOD and POD activities in plant cell lines were significantly higher than intact plants. The cell lines from sweet potato (Ipomoea batatas) and cassava (Manihot esculeanta) showed the highest POD and SOD activities, respectively, suggesting that the cell cultures of sweet potato and cassava are good biomaterials for the mass production and molecular study of antioxidant enzymes. The average ascorbate content in plant cell lines was several hundred times lower than intact plants, whereas the glutathione content was 2-3 times higher than plants. Interestingly, the ratio of reduced and oxidized ascorbate and glutathione was different from plant species. In conclusion, the results strongly suggest that plant cell cultures are good biomaterials for the study of antioxidative mechanism and the production of useful components including antioxidants.

• Applied Chemistry for Engineering
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• v.4 no.1
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• pp.82-93
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• 1993

To extract the tungsten component from the scheelite by the chlorination process, effects of major variables such as the reducing agent, reaction temperature, reaction time, flow rate of the $Cl_2$ gas, and the particle size of the sample, were examined in the batch-boat system. The optimum conditions for this chlorination process were as follows ; reaction temperature above $700^{\circ}C$, carbon weight ratio to the scheelite 0.08, reaction time 20 min, flow rate of the $Cl_2$ gas $0.6{\ell}/min$, particle size of scheelite ore -200 mesh. Under the above conditions, 99% of tungsten component was extracted from scheelite ore. The diffusion step and chemical reaction step were the rate-determining steps at high and low temperature, respectively. Activation energy was 7.98kcal/mol at high temperature region and 31.2kcal/mol at low temperature one.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.762-771
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• 1996

Chemical and sensory characteristics of kakdugi which was prepared with various radish cultivars and harvesting seasons were analyzed during 7-day storage. Average pH of small radish cultivar kakdugi was higher than that of large ones, and total acidity was lower in small ones. Reducing sugar content was the highest in kakdugi of autumn radish. Organic acids such as lactic, succinic and fumaric acid analyzed by GC increased until the third day of fermentation, whereas volatile isothiocyanates analyzed by GC/MS continued to decline. There was a significant difference in flavor characteristics of large radish kakdugi across seasons, in contrast to no significant difference in those of small radish kakdugi except sweet taste and reducing sugar content in which interaction existed between season and cultivar. Score of overall acceptability was higher in small radish than large ones with Dongja showing the highest score of overall acceptability. Overall acceptability of autumn Dongja kakdugi was positively correlated with radish kakdugi odor and sour odor, respectively, but negatively with total acidity, lactic acid content, sweet taste and pungency, respectively. By multiple regression analysis, overall acceptability in spring Dongja kakdugi is expressed as a function of overall acceptability = -0.1115 + 1.2519 savory taste + 1.5159 malic acid -0.0054 total isothiocyanate + ${\varepsilon}$.

• Korean Journal of Food Science and Technology
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• v.40 no.4
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• pp.382-388
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• 2008

This study examined the nutrient components and physicochemical properties of three new potato cultivars: Gui Valley, Bora Valley, and Gogu Valley, which were acquired from PotatoValley Ltd., and compared them to the Superior cultivar that is widely distributed in food markets. Amino acid, fatty acid, and mineral compositions, as well as total starch, reducing sugar, dietary fiber, vitamin C, and phenolic acid contents were measured. The gelatinization and pasting properties of the potatoes were evaluated using differential scanning calorimetry (DSC) and a rapid visco analyzer (RVA). The three new potato cultivars showed differences for various characteristics compared to the existing Superior cultivar. The Gui valley cultivar has a high potential for processing into items such as French fries or chips, due to its high starch content and low reducing sugar content. Bora valley showed an incredibly high phenolic acid contents, and Gogu valley contained high levels of dietary fiber, minerals, vitamin C, and essential amino acids. Overall, these cultivars are expected to be highly valuable items for develpment and applications of functional food.

• Korean journal of food and cookery science
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• v.30 no.4
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• pp.435-443
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• 2014

In this study, we investigated the quality characteristics of Korean soybean paste, Doenjang, fermented for 6 weeks at room temperature with the addition of 0, 10, 20 and 30% garlic. Samples were analyzed in one-week intervals. The lightness decreased in all samples as the fermentation period and garlic concentration increased. Yellow index decreased in weeks 5~6 compared with weeks 0-1, for which the values were lower for the garlic-added Doenjang than the control. The pH increased, greatly reducung the acidity in week 1 compared with week 0. Significant differences in the pH and acidity were not observed among the sample groups. Amino type nitrogen contents increased continuously up to weeks 5, displaying no significant differences among the sample groups at weeks 5 and 6. In addition, reduction in the sugar content increased depending on the fermentation period. It increased in all sample groups by about 2.5 times after 6 weeks compared with the initial levels. Isoflavone content was also reduced generally depending on the fermentation period. In the early fermentation periods, the aglycone contents were the higher than the glycosides, while the glycoside contents increased over the fermentation period. The presence of Bacillus was not significantly different among the garlic added groups, but yeast was lower in the Doenjang with high garlic content.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.451-459
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• 2013

Korean black raspberry fruits (bokbunja) were collected from 11 different producing regions, and commercial black raspberry wines were obtained from 24 manufacturers. Samples were analyzed for soluble solids, titratable acidity, pH, reducing sugar content, hunter color values, intensity, hue, total phenolic content, and organic acids. The fruit samples showed similar pH levels (3.43-3.52), but significantly differed in total acidity levels (9.98-16.2 g/L). The predominant organic acids in the fruit samples were citric acids (1.39-5.63 mg/mL) and succinic acids (0.25-6.53 mg/mL). Among the samples, black raspberry fruits from Goksung and Nonsan showed the lowest levels of total phenolic content, and the lowest values in intensity. The fruits from Jeongeup and Sunchang showed higher levels of phenolic content, soluble solids, and intensity. Some wine samples, including BH, KO, SR, and SE, showed overall high levels of phenolic content, organic acids like citric and succinic acid, and color values such as $a^*$, $b^*$, and intensity. Other wine samples, including DW, SC, GJ, and NB, were high in acetic acid, color values like $L^*$, and hue.

• Food Science and Preservation
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• v.13 no.5
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• pp.649-654
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• 2006

To enhance beneficial effects of citron fruits, anticancer and antioxidant activities of citron fruits extracts were assessed with or without ascorbic acid. Total phenolic acids and flavonoids of fruits peels and flesh extracts were determined. Fruits peels contained more phenolic acids and flavonoids than those detected in flesh extracts. Scavenging activities of 1,1-diphenyl-2-picrylhydrazyl radicals and reducing powers were increased depending on the concentration. The antioxidant activities on oxidation of linoleic acid emulsion incubated at $50^{\circ}C$ were increased but the effect was small to that of butylated hydroxy toluene and ascorbic acid. The anti-tumorigenic effect of these compounds were investigated. They were shown to inhibit the in vitro proliferation of four human tumorigenic cell lines, HT-29, MCF-7, DU-145 and HepG2, in a doso-dependent manner. This study demonstrated that the antioxidant and anticancer activities of citron fruits extracts were derived from their phenols and flavonoids.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.765-779
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• 2023

The Daum Vent Field (DVF) was newly discovered in the Central Indian Ridge during the hydrothermal expedition by the Korea Institute of Ocean Science & Technology (KIOST) in 2021. In this paper, we describe the detailed mineralogy and geochemistry of hydrothermal chimney and mound to understand the nature of hydrothermal mineralization in the DVF. The mineral assemblages (pyrite±sphalerite±chalcopyrite) of dominant sulfides, FeS contents (mostly <20 mole %) of sphalerite, and (Cu+Zn)/Fe values (0.001-0.22) of bulk compositions indicate that the DVF has an strong affinity with basaltic-hosted seafloor massive sulfide (SMS) deposit along the oceanic ridge. Combined with the predominance of colloform and/or dendritic-textured pyrite and relatively Fe-poor sphalerite in chimneys, the fluid-temperature dependency of trace element systematics (Co, Mn, and Tl) between chimney and mound indicates that the formation of mound was controlled by relatively reducing and high-temperature fluids compared to chimney. The δ³⁴S values (+8.31 to +10.52‰) of pyrite reflect that sulfur and metals were mainly leached from the associated basement rocks (50.6-61.3%) with a contribution from reduced seawater sulfur (38.7-49.4%). This suggests that the fluid-rock interaction, with little effect of magmatic volatile influx, is an important metal source for the sulfide mineralization in the DVF.