• YAKHAK HOEJI
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• v.40 no.2
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• pp.163-169
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• 1996

Glycosidation of 20(S)-protopanaxadiol obtained by the alkaline hydrolysis of total ginsenosides with 2,3,4,6-tetra-O-acetyl-${\alpha$-D-glucopyranosyl bromide in the presence of $CdCO_3$ in benzene-dioxane gave a mixture of acetylated monoglucosides and diglucosides in a total yield of 68%. Under the same condenstion condition, 20-dehydroxyglucosides were formed by dehydration of 12-O-glucosides. The structures of produced glycosides were elucidated as 3-O-${\beta$-D-glucopyranosyl-20(S)-protopanaxadiol, 12-O-${\beta$-D-glucopyranosyl-dammar-20(22), 24-dien-$3{\beta},12{\beta}$-diol, 3,12-di-O-${\beta}$-D-glucopyranosyl-dammar-20(22), 24-dien-$3{\beta},\;12{\beta}$-diol, respectively.

• Korean Journal of Microbiology
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• v.30 no.3
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• pp.213-217
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• 1992

Glucosyltransferase of Streptococcus mutans NCTC 10449 was purified and characterized. It relates with production of insoluble glucan in dental caries. The molecular weight was estimated to be 152.000. The optimum pH and temperature was 6.5 and $35^{\circ}C$. respectively. The enzyme was stable in alkaline pH. The Michaelis constants of the enzyme for releasing of fructose were 48 mM. Hydrolysis rate of insolut~le glucan by tlextranase was higher in S. mutuns NCTC 10449 than that of strains isolated from saliva.

• Journal of the Korean Ceramic Society
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• v.29 no.6
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• pp.496-504
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• 1992

Alumina tubes suitable for the support of gas separation membranes have been prepared by the slipcasting technique. These supports have the average pore size of 0.1 ${\mu}{\textrm}{m}$ within the narrow distribution. The sol-gel dipcoating process of nanoparticulate sols is very sensitive to microstructure of the support, and the coating on the inside surface of the tube is found to be more successful than on the outside surface. Nanoparticulate silica sols (0.82 mol/ι) have been synthesized by an interfacial hydrolysis reaction between TEOS and high alkaline water. When coating an alumina tube with these sols, the minimum limits of the particle size and the aging time required for forming the coated gel layer at the given pH are provided. It is optimum to coat the support with less concentrated sols stabilized through aging for the appropriate time (more than 22 days) at the lower pH (pH 2.0) for producing a reproducible crack free thin film coating in composite membranes.

• Fibers and Polymers
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• v.7 no.3
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• pp.235-240
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• 2006

Polyacrylonitrile (PAN) fiber was grafted with casein after alkaline hydrolysis and chlorination reactions of the original fiber. The structures and morphologies of the casein grafted fiber were characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), and scanning electron microscope (SEM). Moisture absorption, specific electric resistance, water retention value, and mechanical properties were also investigated. The results showed that casein was grafted onto the surface of the PAN fiber and the grafted PAN fiber presented better hygroscopicity compared with the untreated fiber. With proper tensile strength, the modified fiber could still meet the requirement for wearing. A mechanism was proposed to explain the deposit of casein on the synthetic acrylic fiber.

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.169-172
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• 2004

A gas chromatography/mass spectrometric assay method was developed for the determination of propylene oxide adduct, N-(3-hydroxypropyl)valine. Adduct was released from hemoglobin by alkaline hydrolysis and extract at pH 8 with ethyl ether. The dried extract was completely derivatized with N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA)/TMS-I (100:3). The detection limits of the assay were 0.08 ng/g for N-(3-hydroxypropyl)valine based upon assayed hemoglobin of 0.1 g. The method was applied to the determination of propylene oxide adduct formed in young female Sprague-Dawley rats after treatment for 1, 2 and 3 weeks with 0.008 % propylene oxide via the drinking water. An adduct was detected by proposed procedure. The structure of the adduct could be assigned to N-(3-hydroxypropyl)valine.

• Archives of Pharmacal Research
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• v.13 no.2
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• pp.142-146
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• 1990

Reaction of ethyl 4-chloro-2-phenylpyrimidine-4-carboxylate (4) with 5-chloro-2-methylthiophenol or 3-aryl-4-phenyl-1, 2, 4-triazole-5 thiol yielded the corresponding thioethers (5) and (8a, b), respectively. Careful alkaline hydrolysis of (5) yielded the corresponding carboxylic acid (6). Reaction of (4) with p-aminoacetophenone yielded compound (10) which was reacted with certain aromatic aldehyde to afford the$\alpha,\beta$-unsaturated ketones (11a-d). Condensation of (11a-d) with malononitrile or phenylhydrazine yielded the 2-amino-3-cyanopyridines (12a-f) or the 2-pyrazolines (13a, b) respectively. Seven representative compounds were tested for their in vitro antimicrobial activity against some pathogenic micro-organisms, some of them were proved to be active.

• Archives of Pharmacal Research
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• v.17 no.2
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• pp.66-70
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• 1994

The condensation reactions of hippuric acid and tis furyl derivative with salicyladehydes or that of salicylhippuric acid analogues with furadehyde led to the comesponding oxazoles. These wre subsequently treated with hydrazine hydrate, hydroxylamine or subjected to alkaline hydrolysis to yield new o-hydroxyaryl or salicyl containing derivatives. 5-Substituted salicylanilides were treated with piperidine and formaldehyde in a Mannich type reaction affording the corresponding 3-(N-piperidinomethyl) salicylanilides. It was noticed that the presence of an electron donating group in in position 3 in the salicylanilide moiety decrease the mollusicidal activity.

• YAKHAK HOEJI
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• v.31 no.4
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• pp.219-223
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• 1987

2-Cyclohexylimino-3-cyclohexyl-5-methyl-4-oxo-2H, 5H-1, 3-oxazino [5,6-C]-1, 2-benzothiazine-6,6-dioxide 2 was hydrolized in d-HCl/$CH_3$CN to give 5-methyl-3-cyclohexyl-2H, 5H-1, 3-oxazino [5, 6-C]-1, 2-benzothiazine-2, 4(3H)-dione 6, 6-dioxide 3 in 82% yield. The alkaline hydrolysis of 3 afforded to 4-hydroxy-2-methyl-N-(cyclohexyl)-2H-1, 2-benzothiazine-3-carboxamide-1, 1-dioxide 4 in 88% yield. On the other hand 3 was synthesized from 4 and ethylchloroformate on the reversed procedure.

• Journal of the Korean Home Economics Association
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• v.38 no.10
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• pp.133-142
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• 2000

The subjective hand and preference of enzyme hydrolyzed denim fabrics were evaluated using the scale developed. The factors affecting consumer's taste for polyester fabrics were analyzed by the statistical technique. The effects of alkaline hydrolysis on the properties of polyester fabrics were evaluated by subjective and objective hand measurements. The lower the age of evaluators, the more sensitive their feeling. As the age decreased, evaluators felt fabrics become flossy and soft surface property is smooth, flexible, warm, refined. They didn't catch the sense of durability, moisture related property and sense of shape recovery. The lower the age, the fabric was more preferred. Women were more sensitive and consistent than men.

• YAKHAK HOEJI
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• v.35 no.5
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• pp.432-437
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• 1991

A mixture of 20(R)- and 20(S)-ginsenoside Rg$_{3}$ was obtained under mild acidic hydrolysis from protopanaxadiol saponins, ginsenosides Rb$_{1}$, Rb$_{2}$, Rc and Rd. The product was acetylated to give the peracetates, which were further converted into 20(R)-ginsenoside Rg$_{3}$, 20(S)-ginsenoside Rg$_{3}$, 20(R)-ginsenoside Rh$_{2}$ and 20(S)-ginsenoside Rh$_{2}$ by the direct alkaline treatment depending upon two kinds of temperature conditions respectively. The structure and physicochemical properties of a prosapogenin, 20(R)-ginsenoside Rh$_{2}$, were investigated.