• Korean Journal of Food Science and Technology
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• v.10 no.4
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• pp.380-386
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• 1978

Enzymatic characteristics of glucose isomerase from Streptomyces spp. K-14 were studied. The optimum pH and temperature of the enzyme reaction are $pH\;7.5{\sim}8.0$ and $70^{\circ}{\sim}75^{\circ}C$, respectively, in the presence of 5 mM $MgSO_4{\cdot}7H_2O$ and 2 mM $CoCl_2{\cdot}6H_2O$. The enzyme activity was activated by both $Mg^{++}$ and $Co.^{++}\;Mg^{++}$ is required for the initial activation of the isomerization reaction, whereas $Co^{++}$ was essential for the increased stability of the enzyme protein. Glucose concentration up to 60% did not affect the reaction velocity as well as the equilibrium conversion of the enzyme.

• The Journal of Internal Korean Medicine
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• v.21 no.2
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• pp.227-234
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• 2000

독성약물에 의한 급성신부전시 세뇨관세포의 물질 재흡수 장애에 대한 단삼(丹參) 추출액의 효과를 조사하였다. 토끼에 수은(HgCl2)을 10 mg/kg되게 피하 주사하여 급성신부전을 유발하였고, 단삼(丹參) 추출액의 효과는 수은을 주사하기 전 7일 동안 0.05% 액(液) 0.3 g/kg 용량을 경구 투여하여 관찰하였다. 수은을 주사하기 전 24시간 동안 요와 혈액을 채취하여 신장기능을 측정하여 대조기간(basal period)의 값으로 하였고, 수은을 주사한 후 24시간 동안 요와 혈액을 얻어 수은에 의한 신장기능 변화를 평가하였다. 수은을 처리한 후 사구체여과율이 대조값에 비해 감소하였고, 혈청내 creatinine 농도가 증가하였다. 이러한 결과들은 수은이 급성신부전을 유발하였음을 가리킨다. 수은을 처리한 동물에서 포도당 및 인산의 배설분율이 증가하였고, 이러한 변화는 brush-border membrane에서 물질의 이동장애와 Na-pump 활성의 감소에 기인하였다. 수은을 주사한 동물의 신장피질 절편에서 유기이온인 PAH와 TEA 이동이 억제되었다. 토끼의 신장조직에서 지질의 과산화가 수은을 주사한 후 증가하였다. 단삼(丹參) 추출액을 전 처리한 후 수은을 주사한 경우 수은에 의해 유발된 사구체여과율의 감소와 혈청내 creatinine 농도 증가 현상이 유의하게 완화되었다. 수은에 의한 세뇨관에서 물질의 재흡수 장애가 단삼(丹參) 추출액의 전처리에 의해 방지되었다. 단삼(丹參) 추출액은 수은에 의한 지질의 과산화를 억제하였다. 수은에 의한 급성신부전은 항산화제로 잘 알려진 DPPD에 의해 방지되었다. 이상의 결과를 종합하면 생체실험결과 수은에 의한 급성신부전의 유발과정에 지질의 과산화가 중요한 역할을 할 가능성을 보이고 있고, 단삼(丹參) 추출액은 수은에 의한 급성신부전을 방지하는 효과를 가지고 있으며, 그 효과는 단삼(丹參)의 항산화작용에 기인(起因)할 가능성이 많다.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.2
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• pp.53-58
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• 1999

This study was carried out evaluate to identify water quality and contamination characteristics of the shallow groundwater. and their seasonal variation in the rual area of the Yongin city. Groundwater sample were collected two times (in April and September) from a total of 19 well for domestic water supply. and surface-water samples from six locations. For cations, Ca and Mg predominated. In anion competition. the influence of Cl was obvious in the april samples. However. HCO$_3$ was a major component in the september samples. Electric conductivities and the concentrations of NO$_3$-N in groundwater samples significantly decreased from the april samples to the september samples This indicates a significant seasonal variation in the shallow groundwater composition. When the shallow aquifer is connected to the surface water. then metals sorbed on the stream sediments could occur at nearby wells through the induced recharge. Contaminants at ground surface appeared to be transported to the groundwater system infiltration during the spring melt.

• Food Science and Preservation
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• v.12 no.5
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• pp.489-495
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• 2005

Polyphenol oxidase (PPO) from Burdock (Arctium lappa L.) was purified and characterized. Purification of polyphenol oxidase was achieved by ammonium sulfate precipitation, Phenyl-sepharose CL-4B hydrophobic chromatography and Sephadex G-100 gel filtration chromatography. The molecular mass of the purified PPO was estimated to be 30 kDa by SDS polyacrylamide gel electrophoresis. In a substrate specificity, maximum activity was achieved with chlorogenic acid, followed by catechol and catechin. Whereas, there was low activity with hydroquinic acid, resorcinol or tyrosine. The optimum pH and temperature for enzyme activity were 7.0 and 35$\circC$ with catechol, respectively. The enzyme was most stable at pH 7.0 while unstable at acidic and alkaline pH. The enzyme was stable when heated to 40$\circC$. But heating at 50$\circC$ for more than 30 min caused 50% loss of activity. Ascorbic acid, L-cystein and $Cu^{2+}$ inhibited the activity of pholyphenol oxidase.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.613-617
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• 2010

Ferro-Nickel slag is one of the by-products in Ferro-Nickel manufacturing process. The slag is composed of $SiO_2$, MgO, $Fe_2O_3$ and others. But the slag has been buried at landfill despite having valuable elements. This study tried to extract Mg ion and fabricate Mg compound from ferro-nickel slag using hydrochloric acid solution. Mg ion was extracted with Si, Fe and other ions in HCl solution. So reprocess was needed for gaining high purity Mg ion. It was thought that Si ion or $SiO_2$ precipitated in HCl solution and removed from solution in filtering process. Fe ion converted into $Fe(OH)_3$ after reacted with $NH_4OH$ and precipitated in HCl solution. After these process, the filtrate was composed of high purity Mg ion. $MgCl_2{\cdot}NH_4Cl{\cdot}6H_2O$ was obtained through drying of filtrate and this product was changed into MgO by burning process ($600^{\circ}C$-30 min). That is, 1st material or solution for manufacturing 2nd product was fabricated using acid dissolution method and other treatments.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.6
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• pp.303-308
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• 2017

The $FeCl_3$ waste solution used to etch various metals contains valuable metal such as nickel. In this study, we recovered as high purity nickel carbonate crystalline powders from nickel-containing etching waste solution after regeneration of iron chloride. Firstly we eliminated about of the iron impurities under the condition of pH 4 using 5 % NaOH aqueous solution and then removed the remaining impurities such as Ca, Mn and Zn etc. by using solvent extractant D2EHPA (Di-(2-ethylhexyl) phosphoric acid). Thereafter, nickel carbonate powder having a purity of 99.9 % or more was obtained through reaction with sodium carbonate in a nickel chloride solution.

• Membrane Journal
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• v.28 no.4
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• pp.286-295
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• 2018

A novel multi-valent salt based on polyethyleneimine having molecular weight of 800 (PEI 800) has been synthesized and characterized as forward osmosis draws solute. A reaction intermediate was synthesized by the neutralization reaction of polyethyleneimine and methyl acrylate, and was hydrolyzed with potassium hydroxide to synthesize a water soluble carboxylic acid (potassium salt) polyethyleneimine. NMR spectrometry, viscometry measurements and osmometry measurements was performed to characterize the draw solute. Forward osmosis experiments were done to know whether the solute could be used as a draw solute or not. The result shows comparable water flux and lower reverse salt flux compared with NaCl as a draw solute. We have also demonstrated recycling of the draw solute in the FO-NF integrated process.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.748-758
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• 2014

The purpose of this study is to find the optimum conditions for manufacturing titanium dioxide using a hybrid self-assembly forming method, to confirm the shape, properties and synergy effect of UV protection for hybrid titanium dioxide. Hybrid titanium dioxide, manufactured by forming self-assembly of different sizes consisting of two kinds of titanium dioxides, has micro titanium dioxide (250nm~300nm) for support material, Nano titanium dioxide (20~30nm) for surface material, coating support material. Adjustment experiments of $AlCl_3$ concentration and both titanium dioxide ratio were conducted to find the optimized conditions for the surface coating of titanium dioxide striking a negative charge, a sample made of the optimized process was confirmed through an optical analysis, particle size analysis, and potentiometric analysis. The SPF in-vitro value of the cosmetics samples containing hybrid titanium dioxide showed 15~30% higher levels than the cosmetics samples containing both titanium dioxides mixture.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.93-105
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• 2012

Activity coefficients and solubilities of L-Valine and L-Proline in aqueous solutions containing each of four electrolytes such as NaCl, KCl, $NaNO_3$ and $KNO_3$ were measured at 298.15 K. The measurements of activity coefficients were carried out in the electrochemical cell coupled with two ion-selective electrodes (cation and anion), and the solubilities were measured by the gravimetric analysis of saturated solutions in equilibrium with the solid phase of amino acid. The measured activity coefficients of electrolytes and amino acids were correlated with the theoretical thermodynamic model presented in the previous work [Korean Chem. Eng. Res. 48(4), 519(2010)]. It was found that the activity coefficients of amino acids and electrolytes described based on the our previous model were well agreeable with experimental data. Also the experimental solubility data of L-Valine and L-Proline were successfully correlated with the thermodynamic relation mentioned in the previous work.

• Korean Journal of Food Science and Technology
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• v.26 no.4
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• pp.375-381
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• 1994

A bacterial strain No. KY-126, which produced extracellular cyclodextrin glycosyltransferase(CGTase), was isolated from soil and identified as Bacillus stearothermophilus KY-126. The enzyme was purified by the treatments of ammonium sulfate precipitation, DEAF-Sephadex, Sephadex G-100 column chromatography. The optimal pH and temperature for the enzyme activity were pH 5.5 and $65^{\circ}C$, respectively. And the enzyme was stable at pH values from 6.0 to 11.0 at $55^{\circ}C$ for 30 min and stable up to $60^{\circ}C$ for 30 min.. The enzyme was inhibited by $HgCl_{2}$. The molecular weight of the enzyme was estimated to be 67,000 by using SDS-PAGE. The maximum conversion from starch to cyclodextrin (CD) by CGTase was 43% and obtained at 6 hr reaction and the ratio of ${\alpha}-,\;{\beta}-,\;{\gamma}-$, CD production at this time was 2.9 : 2.1 : 1.0.