• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2156-2162
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• 2012

Many literatures focus on the biological relevance and the identification of biomarkers for disease activity assessment while less attention has been paid to the development of standard procedures for sample preparation and storage based on liquid chromatography technique. The influencing factors including protein precipitation, storage temperature, storage time, and reconstitution by ultra pure water were analyzed employing HPLC-DAD. The effects were investigated from five participants over three months by principal components analysis (PCA) and the values of percent changes (PC). The samples with protein precipitation might slow the rate of bacterial enzymatic conversion. After protein precipitation, the average PC of urine samples ($0.136{\pm}0.013$, n = 5) is relatively less than that of the serum samples ($0.173{\pm}0.026$, n = 5) for three months. Minimal effects on metabolic profiles of serum and urine (PC < 0.15) are reasonable for metabolomic studies after protein precipitation and storage at $-20^{\circ}C$ for two months.

• Journal of the Korean Chemical Society
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• v.40 no.6
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• pp.420-426
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• 1996

The critical micelle concentration(CMC) and the counterion binding $constant(\beta)$ at the CMC of the mixtures of Sodium dodecylsulfate(SDS) with Sodium dodecylbenzenesulfonate(DBS) in aqueous solutions have been determined from the concentration dependence of electrical conductance at several temperatures from $15^{\circ}C$ to $35^{\circ}C.$ Thermodynamic parameters(${\Delta}C_p,\;{\Delta}G_m^{\circ},\;{\Delta}H_m^{\circ}$ 및 ${\Delta}S_m^{\circ}$ and ${\Delta}C_p$), associated with the micelle formation of SDS/DBS mixtures, have been estimated from the temperature dependence of CMC and $\beta$ values. The measured values of ${\Delta}G_m^{\circ}\;and\;{\Delta}C_p$ are negative but the values of ${\Delta}S_m/^{\circ}$ are positive in the whole measured temperature region. The significance of these thermodynamic parameters and their relation to the theory of the micelle formation of SDS/DBS mixtures have been also considered.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.21 no.2
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• pp.1-21
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• 1995

In this context, it should be mentioned that multilamellar vesicles can be prepared with the main compounds of the intercellular lipids, ceramides, cholesterol, cholesteryl ester, squalane, lecithin, wax ester by effect of the wetting. We investigated properties formation of MLV with use of the AHAsomes and Microfluidizer. The multilamellar vesicles are formed merely adding polyol and water phase, followed with the microfluidizer. Formation of a practically pure AHAsomes system, containing the active ingredients directly incorporated without need for preservatives. There were very good encapsulated properties of the active ingredients whether hydrophilic(malic acid, tartaric acid, lactic acid, allantoin, urea) and hydrophobic(vitamin-I acetate, vitamin-A palmitate). Optimum condition (ormatiom of MLV was passed three times in the microfluidizer, particle size of the vesicles should be within range 50-523nm (mean=163.5nm). As application, It was compared that horny layer of the sole of foots removal with the general OM emulsion and the AHAsomes cream. There was used for three months, those got recovery wrinkles about 151.8% and elasticity three times more the AHAsomes than O/W emulsions, It was confirmed with the Image Analyzer and the Cutometer.

• Korean Journal of Plant Resources
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• v.24 no.4
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• pp.351-357
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• 2011

This study was carried out to investigate the effective extraction condition for increase of phytoecdysteroids from fronds of Matteuccia struthiopteris (FMS) and Osmunda japonica (FOJ). Lyophilizated fronds were mixed with three different solvents (MeOH, 80% EtOH or water) and then extraction was carried out by using six different methods, such as, immersion (room temp.), heating (60$^{\circ}C$), stirring (200 rpm) for 6 h, or sonication in 42 kHz ultrasonic bath for 15, 30 and 45 minutes. Contents of 20-hydroxyecdysone (20E) and ponasterone A (PonA) were measured by using HPLC after purification of the extracts by $C_{18}$ cartridge. Altogether, our results indicate that the extraction using sonication with MeOH as a solvent (for 30 minutes) was the most effective condition for 20E and PonA from both MFS and FOJ. Resulting contents of 20E from FMS and FOJ were 66.76 and 104.48 ${\mu}g{\cdot}g^{-1}$ and PonA were 53.43 and 43.82 ${\mu}g{\cdot}g^{-1}$, respectively.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.17-24
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• 2000

Reverse osmosis (RO) system was applied to improve wine quality. General wine (GEN) and wines containing different sugar levels $24^{\circ}Brix$ (RO-24) and $24^{\circ}Brix$ (RO-28) by removing pure water using RO system without sugar addition on brewing method. And they were compared by wine aroma analysis. The preparing method of analysis was LLCE (liquid-liquid continuous extraction). And volatile aroma compounds of different wines were prepared for raw, and diluted materials in same proportion. The wine aromas were described by trained twelve panelists for QDA (quantitative descriptive analysis) and showed for FD (flavor dilution)-chromatogram. Consequently, overall acceptability of RO-28 showed better than that of other treatments. Aromas of RO-28 also were represented the high contents of positive aroma compounds such as ethanol and ethyl acetate, which were identified by GC-O and GC-MS.

• Journal of the Korean Ceramic Society
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• v.54 no.3
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• pp.243-248
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• 2017

Pd-doped $SnO_2$ thick film with a pure tetragonal phase was prepared on patterned Pt electrodes by an ink dropping method. Nanostructured $SnO_2$ powder with a diameter of 10 nm was obtained by a modified hydrazine method. Then the ink solution was fabricated by mixing water, glycerol, bicine and the Pd-doped $SnO_2$ powder. When the Pd doping concentration was increased, the grain size of the Pd-doped $SnO_2$ thick film became smaller. However, an agglomerated and extruded surface morphology was observed for the films with Pd addition over 4 wt%. The orthorhombic phase disappeared even at a low Pd doping concentration and a PdO peak was obtained for a high Pd doping concentration. The crack-free Pd-doped $SnO_2$ thick films were able to successfully fill the $30{\mu}m$ gap of the patterned Pt electrodes by the optimized ink dropping method. The prepared 3 wt% Pd-doped $SnO_2$ thick films showed monoxide gas responses ($R_{air}/R_{CO}$) of 4.0 and 35.6 for 100 and 5000 ppm, respectively.

• Journal of the Korean Ceramic Society
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• v.56 no.3
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• pp.284-290
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• 2019

Ternary MoS₂/graphene (G)-TiO₂ photocatalysts were prepared by a simple hydrothermal method. The morphology, phase structure, band gap, and catalytic properties of the prepared samples were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, UV-vis spectrophotometry, and Brunauer-Emmett-Teller surface area measurement. The H₂ production efficiency of the prepared catalysts was tested in methanol-water mixture under visible light. MoS₂/G-TiO₂ exhibited the highest activity for photocatalytic H₂ production. For 5 wt.% and 1 wt.% MoS₂ and graphene (5MT-1G), the production rate of H₂ was as high as 1989 µmol^-1h^-1. The catalyst 5MT-1G showed H₂ production activity that was ~ 11.3, 5.6, and 4.1 times higher than those of pure TiO₂, 1GT, and 5MT, respectively. The unique structure and morphology of the MoS₂/G-TiO₂ photocatalyst contributed to its improved hydrogen production efficiency under visible light.

• Journal of Pharmaceutical Investigation
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• v.8 no.1
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• pp.6-16
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• 1978

We obtained 4 kinds of extract fraction from Acanthopanacis Radicis Cortex and studied on the influence to the blood pressure of rabbit. These 4 fractions were obtained as follows; Fraction I was insoluble fraction by 99% ethanol from 80% methanol extract of Acanthopanacis Radicis Cortex, fraction II, precipitated fraction by ether from 99% ethanol soluble fraction of 80% methanol extract of Acanthopanaacis Radicis Cortex, fraction III, no precipitated fraction by ether from 99% ethanol soluble fraction of above 80% methanol extract and fraction IV, water extract of Acanthopanacis Radicis Cortex. All of fractions, when administered into ear-vein of rabbit, produced fall of blood pressure. Among these 4 fractions, although fraction III was not only the most potent but had the greatest efficacy, we observed the mechanism of hypotensive action of Acanthopanacis Radicis Cortex, making use of fraction II which was thought as a comparatively pure fraction. Hypotensive action of fraction II (APF II) was not affected by vagotominization but markedly inhibited by atropine. Pretreatment of bethanidine showed a tendency to weaken the depressor action of APF II, although it was not a significant result, but diphenhydramine did not influence APF II action. Phentolamine, guanethidine and chlorisondamine inhibited significantly the hypotensive action of APF II. APF II elicited the potentiation of norepinphrine pressor action dependent on the time-factor whereas it did not influence angiotesin pressor action. It is seemed that APF II exhibited hypotensive action, causing peripheral muscarinic-effect and centrally induced sympatholytic action.

• Journal of Pharmaceutical Investigation
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• v.34 no.6
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• pp.443-452
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• 2004

Habit is the description of the outer appearance of a crystal. If the environment of a growing crystal affects its external shape without changing its internal structure, a different habit results. Crystal habit and the internal structure of a drug can affect bulk and physicochemical properties, which range from flowability to chemical stability. A polymorph is a solid crystalline phase of a given compound resulting from the possibility of at least two different arrangements of the molecules of that compound in the solid state. Chemical stability and solubility changes due to polymorphism can have an impact on a drug's bioavailability and its development program. During crystallization from a solution, crystals separating may consist of a pure component or be a molecular compound. Solvates are molecular complexes that have incorporated the crystallizing solvent molecule in their lattice. When the solvent incorporated in the solvate is water, it is called a hydrate. To distinguish solvates from polymorphs, which are not molecular compounds, the term pseudopolymorph is used. Identification of possible hydrate compounds is important since their aqueous solubilities can be significantly less than their anhydrous forms. Conversion of an anhydrous compound to a hydrate within the dosage form may reduce the dissolution rate and extent of drug absorption. An amorphous solid may be treated as a supercooled liquid in which the arrangement of molecules is random. Amorphous solids lack the three-dimensional long-range order found in crystalline solids. Since amorphous forms are usually of higher thermodynamic energy than corresponding crystalline forms, solubilities as well as dissolution rates are generally greater. A study on crystal form includes characterization of (l)crystal habit, (2)polymorphism, (3)pseudopolymorphism, (4)amorphous solid.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.10
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• pp.85-90
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• 1971

Dormancy breaking methods were studied on Avenasterilis seeds. The treatments were: application of alcohol, hot water, low temperature, pure oxygen, thiourea and gibberellic acid. Thiourea treatment with 3 different concentrations (0.25 x 10$^{-2}$ M, 0.625 x 10$^{-2}$ M, 1.25 x 10$^{-2}$ M) had little effect in breaking dormancy. Gibberellic acid treatment applied at 5ppm, 50ppm, 500ppm were effective and maximum germination was obtained with 500ppm. Low temperature treatment at 3$^{\circ}C$ for a week in a refrigerator was also very effective in breaking dormancy. Other treatments were not effective. In all cases, primary seeds germinated significantly better than secondary seeds. Different A. sterilis strains varied significantly in their response to gibberellic acid treatment. Different concentrations of gibberellic acid also gave significantly different responses in breaking dormancy.