• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.347-352
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• 1983

To characterize humus fractions in soil, visible, ultraviolet and infrared absorption spectra of humic acids in alkaline solutions and hymatomelanic acids in ethanol solutions extracted by Stevenson's method from paddy rice soils, peats, and volcanic ash soils were analyzed. The spectra patterns of both fractions in visible and ultraviolet ranges did not have any peak and the absorbance decreased as the wavelength increased. Visible and ultraviolet spectra of the solutions from all the peats, volcanic ash soils and paddy rice soil were very similar each other but absorbances were slowly declined in the order of volcanic ash soils, peats and mineral paddy soils. The infrared spectra of the two solutions appeared in a typical pattern, showing a few broad peaks. The main absorption bands were in the regions of $3400cm^{-1}$ (hydrogen bonded OH), near $2900cm^{-1}$ (aliphatic CH), $1720cm^{-1}$ (C=O of COOH, C=O of carbonyl), $1625cm^{-1}$ (aromatic C-C conjugated with C=O and/or COO-), $1400-1450cm^{-1}$ (CH stretch), $1200-1250cm^{-1}$ (CaO stretch of phenolic OH or OH-deformation of COOH) and $1050cm^{-1}$. The hymatomelanic acid fractions, however, had spectra that were characterized especially by very distinct absorption at $2900cm^{-1}$ and $1720cm^{-1}$, for aliphatic CH and carbonyl stretching vibration respectively in addition to the weaker bands for COO- or aromatic CH vibration at $1625cm^{-1}$, as compared to humic acid. No differences were noted in the general patterns of the spectograms of both fractions extracted. Analyses of the functional groups revealed little differences between peats and paddy soils, although total acidity and the content of carboxyl groups were decreased in the order of volcanic ash soils, peats and mineral paddy soils.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.361-369
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• 2000

Enterococcus is a normal inhabitant of the human oral cavity, the vagina, and the gastrointestinal tract. Four isolates of Enterococcus in this study were identified as E. durans. These bacteria were characterized and the interaction of these bacteria with the important oral bacteria as like S. mutans and S. oralis was studied as follows. 1. The carbohydrate fermentation test and biochemical test showed similar results in 4 isolates. 2. The susceptibility test against erythromycin, penicillin, tobramycin, ampicillin, teicoplanin, ciprofloxacin, vancomycin, gentamicin, kanamycin, and streptomycin showed to be susceptible in all four isolates. 3. The optical density of absorbance at 550 nm was 1.405 in the culture of S. mutans in disposable cuvette, whereas being 0.855, 0.867, 0.797, and 1.083 in the combined culture of S. mutans and each E. durans. 4. The mean weight of produced artificial plaque on the wires in the beaker was $1566{\pm}103mg$ in culture of S. mutans only, whereas being reduced to $44{\pm}5mg,\;41{\pm}12mg,\;34{\pm}7mg,\;and\;38{\pm}12mg$ in the combined culture of S. mutans and each E. durans. The viable cells were $2.0\times10^9$ per ml in the culture of S. mutans wheras being $2.0\times10^7\;to\;6.0\times10^7$ per ml in the combined culture S. mutans and E. durans. 5. The viable cells were $2.1\times10^8$ per ml in the culture of S. oralis, wheras being $1.4\times10^7\;to\;7.0\times10^7$ per ml in the combined culture of S. oralis and E. durans. 6. Plasmid of about 60 kb was isolated in three isolates of E. durans. These results suggested that E. durans isolated from the oral cavity inhibited the replication of S. mutans and formation of artificial plaque, while inhibiting the replication of S. oralis a little.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.3
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• pp.366-372
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• 2006

This study is to investigate the physicochemical properties of differently pretreated chestnut starches during starch isolation and to examine their gelatinization properties by both heat and alkali treatments. One kind is starch A made by alkali method from peeled chestnut. The other is starch B made from chestnut with the outer layer. The results are as follows. Starch A has higher water binding capacity of 86.9% than starch B with 80.66%. Swelling powers of both starch A and B increased rapidly from $60^{\circ}C\;to\;80^{\circ}C$ in both, and since then it has changed a bit. Both began to show their solubility at $60^{\circ}C$ and increased continuously as the temperature went up. Starch A has higher swelling power and solubility than starch B. In iodine reaction, starch A has higher ${\lambda}max$ and absorbance at ${\lambda}max$ than starch B. X-ray diffraction patterns showed that starch A is type $C_b$ and that starch B is type B. Starch B has higher relative crystallinity of 37.0% than starch A with 36.2%. The results by differential scanning calorimetry revealed that starch A gelatinized from $66.95^{\circ}C$ to $77.5^{\circ}C$ and its enthalpy is 2.04 cal/g. And starch B gelatinized from $67.09^{\circ}C\;to\;77.5^{\circ}C$, and its enthalpy is 2.29 cal/g. Amylograms of chestnut starch at 6.5% concentration indicated that starch B needs higher onset temperature when beginning to gelatinize than starch A does. But starch A shows much higher peak viscosity, breakdown and setback than starch B does. Starch A shows higher viscosity, gel volume, and optical transmittance in gelatinization properties by alkali than starch B does.