• 펄프종이기술
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• 제31권1호
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• pp.89-94
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• 1999

The inorganic compositions of traditional lye, and lyes prepared from the stalks of five different agricultural products: beans, wheat, barley, buckwheat and red peppers, were analyzed. Traditional lye was composed mainly of a weak alkaline salt, potassium carbonate as the major component and neutral salts, potassium chloride and potassium sulfate as minor components. The ash and lye contents of buckwheat have significantly higher then those of the rest agricultgural products. Bean and red pepper stalks lyes were composed mainly of potassium carbonate, similar to the composition of traditional lye, but also contained potassium chloride or sulfate. In contrast, postassium chloride was the major component of wheat and barley stalk lye.

• 한국의류산업학회지
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• 제4권1호
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• pp.86-91
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• 2002

To estimate dispersion stability of particles, suspending power and particle size were examined as functions of pHs, surfactants, electrolytes and ionic strengths using ${\alpha}-Fe_2O_3$ particle as the model of particulate soil. Suspending power and particle size were determined by UV-Vis spectrumeter and by light scattering using the polarization ratio method, respectively. The suspending power was relatively high with polyanion electrolytes and was low with neutral salts. The suspending power was biphasis, minimum pH 6~7, and the effect of surfactant on the suspending power was insignificant. Generally suspending power increased with decreasing the particle size governed aggregation of dispersed particles regardless of solution conditions. Hence the suspending power was inversely related to the particle size.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권6호
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• pp.395-401
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• 2001

Crystallins are a family of water-soluble proteins that constitute up to 90% of the wa-ter-soluble proteins in mammalian eye lenses, We present in this paper an alternative purification method for these proteins using polyethylene glycol/dextran aqueous two-phase extraction. Un-der the appropriate conditions, we were able to recover the γ-crystallin fraction essentially free of the remaining proteins. High concentrations of salt at a neutral pH maximize the recovery of γ-crystallins in the top phase and minimize the contamination by the other proteins present in the lenses. The proposed protocol decreases the separation time by about 50%. The complex partition behavior observed for these proteins reflects a delicate balance between protein/phase-forming species(various polymers and salts) and protein interactions. This is evidenced, in part, by the role played by the largest proteins in this group as a "pseudo"phase-forming species.

• Macromolecular Research
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• 제17권5호
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• pp.332-338
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• 2009

Rheological behavior of natural hydrogel produced from seeds of three Salvia spp. (S. miltiorrhiza (SM), S. sclarea (SS), S. viridis (SV)) was investigated by using a Rheometer equipped with a cone and plate geometry measuring system under never-dried condition. Different chemical contents of such hydrogels give significant effects on their rheological properties. Because of incomplete penetration of water inside the hydrogels after drying before-dried hydrogels were used for rheological analysis. To know molecular interactions which predominated in the gel formation, some constituents were externally added to the 1.0% (w/w) hydrogel. Addition of urea to disrupt hydrogen bonds reduced 3.4-67% viscosity of the untreated hydrogels and changed viscoelastic properties from gel to liquid-like behavior. Neutral salts added to the hydrogel solution at 0.1 M also lowered the viscosity in a manner related with increase in size of cations and temperature. Changing from gel state to liquid-like state was also easily confirmed by oscillation measurement (storage, G', and loss, G", modulii) typically observed in the cases of potassium sulfate and potassium thiocyanate. Influence of pH variation on the viscosity explained that weak alkaline condition (pH 8-9) creates a higher resistance to flow due to increasingly electrostatic repulsions between negative charges ($COO^-$) Importance of calcium bridges was also demonstrated by recovery of viscosity of the hydrogels by addition of calcium after acidification. The summarized results indicate that electrostatic repulsion is a major contributor for production of hydrogel structure.

• Applied Biological Chemistry
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• 제28권2호
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• pp.88-91
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• 1985

한국산 인삼 단백질의 생화학적 특성을 체계적으로 규명하기 위하여 단백질의 분별정량, SDS polyacrylamide gel 전기영동, pH에 의한 단백질의 용출성 및 아미노산 포성을 분석한 결과는 다음과 같다. 인삼 단백질의 분별정량은 albumin이 66.0%로 가장 많았으며 glutelin이 20.5%이었고 인삼 단백질의 pH에 의한 용출성은 pH3에서 최저를 나타내었으며 $pH6{\sim}8$에서 최고치를 나타내었고 염의 종류 및 그 농도별에 의한 추출성은 sodium염의 경우 차이가 없었다. 수용성 단백질의 침전도는 40%의 ammonium sulfate와 acetone에 의하여 96% 침전하였으며 SDS-poly-acrylamide gel 전기영동의 결과 11개의 band가 확인되었으며 수용성 단백질의 주 단백질의 분자량은 43,000이었다. 수용성 단백질의 아미노산조성은 18종류로써 arginine의 함량이 45.17%로 가장 많았으며 proline 및 cystine의 함량은 매우 낮았다.

• 치위생과학회지
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• 제14권2호
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• pp.191-197
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• 2014

본 연구는 전문가의 지도 없이 소비자가 쉽게 구매할 수 있는 일반적 치아 미백제에 대한 연구로 과산화수소의 함량제한이 있는 국내 사용 환경에서 보다 효과적인 미백 효능을 제공하고자 동일 과산화수소 함량에서 미백 효과를 증진시켜 줄 수 있는 금속 이온 등을 함유한 primer에 대해 착색시킨 수산화인회석 시편을 이용한 실험실적 방법으로 미백효과를 평가하였다. 평가원료들은 인체 안전성을 고려하여 식품 첨가물 공전에 수재된 원료에서 선별하였으며 금속 이온의 종류 및 염의 종류에 따른 효과를 평가한 결과 3가 철 이온을 방출하는 염화제이철을 함유한 primer를 적용 시 미백 효과가 가장 우수하였다. 여기에 제삼인산칼륨을 사용하여 pH를 알칼리조건으로 만든 pH 10.0 primer를 적용 시 더욱 미백 효과가 증가됨을 확인하였으며 primer를 사용하지 않은 대조군과 시간에 따른 미백 효과를 비교한 결과 30분 부착 시 1.75배의 명도 변화량을 나타내었다. 본 연구는 인공 재료와 인공적 실험 환경에서 이뤄진 실험실적 연구로서 실제 인체에 적용 시 안전성이나 부수적 효과에 대해서는 추후 추가적으로 평가해야 할 필요가 있으나 제한된 과산화수소 함량에서 primer의 사용으로 미백 효과를 극대화할 수 있다는 것을 확인하였다는 점에서 의미가 있다고 생각된다.

• Journal of Nutrition and Health
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• 제26권1호
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• pp.13-20
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• 1993

To investigate the effects mustard leaf(Brassica Juncea) on Cholesterol metabolism, male Sprague Dawley rate were fed semipurified diets containing 2% or 4% mustard leaf with or without cholesterol for 5 weeks. Plasma cholesterol content decreased significantly by feeding 4% mustard leaf with of without cholesterol for 5 weeks. Plasma cholesterol content decreased significantly by feeding 4% mustard leaf in rats fed 1% cholesterol in the diet. In addition, HDL-cholesterol increased slightly by the feeding of mustard leaf, resulting in a significant increase in the HDL-cholesterol/total cholesterol ratio and a reduction of atherosclerotic index. However, levels of plasma lipids were not influenced by mustared leaf in rats fed cholesterol-free diet. The contents of all classes of lipid in liver increased by dietary cholesterol. Of the liver lipids, triglyceride and cholesterol ester were accumulated most, showing a fatty liver synodrome. Supplementation of mustard leaf to cholesterol-containing diet resulted in a slight decrease in neutral lipid contents of liver. Fecal cholesterol excretion was higher by more than 2.7 and 3.3-fold in rats fed 2 and 4% mustard leaf than in control rats fed cholesterol. Similar trends were found in fecal bile salt excretion; rats fed and 4% mustard leaf excreted more bile salts by more than 1.5 and 2% than those fed control diet containing cholesterol. In summary, mustard leaf may have an antiatherogenci effect of reducing plasma cholesterol level and increasing HDL-cholesterol level. The plasma cholesterol lowering effect of mustard leaf is suggested to be due, at least in part, to increase in fecal excretion of cholesterol and bile acids.

• Membrane and Water Treatment
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• 제5권4호
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• pp.235-250
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• 2014

The impacts of membrane degradation due to chlorine attack on the rejection of inorganic salts and trace organic contaminants by nanofiltration (NF) and reverse osmosis (RO) membranes were investigated in this study. The rejection of trace contaminants was examined at environmentally relevant concentrations. Changes in the membrane surface morphology were observed as a result of chlorine exposure. A small increase in rejection was consistently observed with all four membranes selected in this study after being exposed to a low concentration of hypochlorite (100 ppm). In contrast, a higher concentration of hypochlorite (i.e., 2000 ppm) could be detrimental to the membrane separation capacity. Membranes with severe chlorine impact showed a considerable decrease in rejection over filtration time, possibly due to rearrangement of the polyamide chains under the influence of chlorine degradation and filtration pressure. The reported results indicate that loose NF membranes are more sensitive to chlorine exposure than RO membranes. The impact of hypochlorite exposure (both positive and negative) on rejection is dependent on the strength of the hypochlorite solution and is more significant for the neutral carbamazepine compound than the negatively charged sulfamethoxazole.

• Corrosion Science and Technology
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• 제19권1호
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• pp.8-15
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• 2020

In this paper, the efficiency and the inhibition mechanisms of cobalt salts (cobalt nitrate and cobalt-exchange silica Co/Si) for the corrosion protection of AA2024 were investigated in a neutral aqueous solution by using the electrochemical impedance spectroscopy (EIS) and polarization curves. The experimental measurements suggest that cobalt cation plays a role as a cathodic inhibitor. The efficiency of cobalt cation was important at the concentration range from 0.001 to 0.01 M. The formation of precipitates of oxides/hydroxides of cobalt on the surface at low inhibitor concentration was confirmed by the Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy (SEM/EDS) analysis. EIS measurements were also conducted for the AA2024 surface covered by water-based epoxy coating comprising Co/Si salt. The results obtained from exposure in the electrolyte demonstrated the improvement of the barrier and inhibition properties of the coating exposed in the electrolyte solution for a lengthy time. The SEM/EDS analysis in artificial scribes of the coating after salt spray testing revealed the release of cobalt cations in the coating defect to induce the barrier layer on the exposed AA2024 substrate.

• Bulletin of the Korean Chemical Society
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• 제13권3호
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• pp.230-235
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• 1992

The conformational analysis has been done for catecholamines (dopamine, norepinephrine, and epinephrine) in the cationic and di-anionic states. The species responsible for adsorption on silver metal surface is anionic deprotonated at hydroxyl groups of catechol moiety, i.e., di-anionic states of catecholamines. This was deduced from Fourier-transform Raman spectra of sodium salts of catecholamines. High resolution proton NMR (400 MHz) spectra of catecholamines in basic and neutral $D_2O$ solution show that the conformations of norepinephrine and epinephrine in the di-anionic states are preferred in gauche, but not for dopamine in the di-anionic state. However the energy difference between trans and gauche of catecholamines in the protonated cationic states is small enough to rotate freely through C-C bond in ethylamine moiety. The conformational calculations using an empirical potential function and the hydration shell model (a program CONBIO) show consistent with above experimental results. The calculations suggest that the species of catecholamines adsorbed on silver metal surface would be in favor of the gauche conformations.