• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.663-678
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• 2018

Refractive index and speeds of sound for the binary mixture of isomer of butanol (1) + cyclohexane, benzene and toluene (2) were measured at 308.15 K. The measured data were used to calculate deviation in refractive index ${\Delta}n$, ultrasonic speed ${\Delta}u$, isentropic compressibility $K_s^E$, available volume $V_a$, excess intermolecular free length $L_f$ and molecular association $M_A$. All the derived properties were correlated with polynomial equation. Ultrasonic speed data were predicted using various empirical correlations like Nomoto, van Dael, impedance dependence and theoretically with Schaaff's collision factor theory (CFT). Jacobson free length theory (FLT) was used to calculate $L_f$. The measured refractive index was also correlated with various mixing rules. The deviation in refractive index Δn and ultrasonic speed ${\Delta}u$ was used to determine the intermolecular interactions.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.316-323
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• 2019

The adsorption of bisphenol A from an aqueous solution onto dried rice husk was investigated. Batch adsorption experiments were performed as a function of the pH, contact time, bisphenol A concentration, adsorbent dose and temperature. The concentration of Bisphenol A was measured by HPLC. The results showed that bisphenol A removal was highest at a solution pH value of 3, adsorbent dose of 4 g/L, and contact time of 75 min. The bisphenol A removal percentage decreased from 99.1 to 66.7%, when the bisphenol A concentration increased from 10 to 200 mg/L. The Langmuir isotherm and pseudo-second order kinetics provided the best fit for the experimental data. Thermodynamic parameters such as ${\Delta}G^0$, ${\Delta}H^0$ and ${\Delta}S^0$ were also evaluated and it was found that the sorption process was feasible, spontaneous and exothermic in nature. Overall, the studied absorbent can be used as an effective and low cost material to treat the industrial wastewater and aqueous solution containing phenolic compounds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1202-1209
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• 2005

The purpose of this study was to observe the effects of high-carbohydrate (HC) diet, high-protein (HP) diet and high-fat (HF) diet with a normal diet (N) on diet-induced thermogenesis (DIT) in healthy Korean women. The four isoenergetic test meals consisted as follows: HC (75$ \% $ energy from carbohydrate, 10$ \% $ from protein and 15$ \% $ from fat), HP (10$ \% $ energy from carbohydrate, 75$ \% $ from protein and 15$ \% $ from fat) HF (15$ \% $ energy from carbohydrate, 10$ \% $ from protein and 75$ \% $ from fat) diet and N (65$ \% $ energy from carbohydrate, 15$ \% $ from protein and 20$ \% $ from fat) diet. Fasting and postprandial thermogenesis were measured after each test meals in eight subjects by indirect calorimetry for 3 hours. Fasting and postprandial serum glucose, insulin and triacylglycerol contents were also measured for 3 hours. DIT were 10.4$\pm$3.2 for HC, 12.7$\pm$0.5 for HP, 6.9$\pm$2.8 for HF and 8.7$\pm$4.8 for N diet as a percentage of the energy load. DIT of HP was greater than HF significantly, but had no differences with HC and N Integrated areas under the curves ($ \delta- $-AUC) of plasma glucose and insulin were significantly higher for HC compared to HP, HF and N diets. $ \delta$-AUC of plasma triacylglycerol was significantly higher for HF compared to the other test meals. In conclusion, intake of protein rich meal stimulates postprandial energy expenditure, but has no relation between DIT and insulin response, body composition.

• Journal of Environmental Health Sciences
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• v.28 no.5
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• pp.4-12
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• 2002

It is well-known method to use Ethylene Oxide (ETO) as a fumigant to preserve cultural heritage from the attack of some bacteria and insects. In this article, we investigated co]or change of some cultural material upon treating ETO. The cultural material was selected from Korean paper (hanji), ancient books, blue prints, pigments (DA, DB, DC, DD, DE and DF). hemp cloths, and colored pictures (DG, DH, Dl, DJ, DK). The $\Delta$E value in chromaticity coordinates for each item was obtained upon treatment with ETO at concentration of 200, 250, 380, 500, 710 g/m$^3$ respectively. The $\Delta$E value was derived from the equation of L*at with the data checked 24 hr, 48 hr, and 72 hrs respectively. The Korean papers(hanji) showed slightly change in color by $\Delta$E 0.8. In the case of ancient books, it showed $\Delta$E 2.91 which was easily distinguishable with the naked eyes. For the almost 73％ of blue prints, the value of $\Delta$E was as much as more than 4.0 that it is recommended not to use. In the case of pigments, the value of $\Delta$E was ranged from 0.15 up to 4.0 so that it should be very careful before use. The hemp cloth dyed with natural indigo showed less than 1.00 in $\Delta$E, while various colored hemp cloth showed wide range of $\Delta$E from 1.00 to 4.00. Finally, from the fact that the color change was as small as less than 1.00 for the colored pictures, it is thought that treatment with ETO is one of method to be used to this purpose.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1555-1562
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• 2010

Development of the strain and the fermentation process of Hansenula polymorpha was implemented for the production of ${\gamma}$-linolenic acid ($GLA,\;C18:3{\Delta}^{6,9,12}$), an n-6 polyunsaturated fatty acid (PUFA) that has been reported to possess a number of health benefits. The mutated ${\Delta}^6$-desaturase (S213A) gene of Mucor rouxii was expressed in H. polymorpha under the control of the methanol oxidase (MOX) promoter. Without the utilization of methanol, a high-cell-density culture of the yeast recombinant carrying the ${\Delta}^6$-desaturase gene was then achieved by fed-batch fermentation under glycerol-limited conditions. As a result, high levels of the ${\Delta}^6$-desaturated products, octadecadienoic acid ($C18:2{\Delta}^{6,9}$), GLA, and stearidonic acid ($C18:4{\Delta}^{6,9,12,15}$), were accumulated under the derepression conditions. The GLA production was also optimized by adjusting the specific growth rate. The results show that the specific growth rate affected both the lipid content and the fatty acid composition of the GLA-producing recombinant. Among the various specific growth rates tested, the highest GLA concentration of 697 mg/l was obtained in the culture with a specific growth rate of 0.08 /h. Interestingly, the fatty acid profile of the yeast recombinant bearing the Mucor ${\Delta}^6$-desaturase gene was similar to that of blackcurrant oil, with both containing similar proportions of n-3 and n-6 essential fatty acids.

• Journal of Soil and Groundwater Environment
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• v.17 no.5
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• pp.10-19
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• 2012

The aim of this study was to examine chemical and isotopic compositions of groundwater and lake water near an area contaminated by petroleum and to evaluate influence of petroleum on them during the period from March to August 2011. In dry season, $Ca^{2+}$ and $SO{_4}^{2-}$ were dominant in the groundwater and lake water and $Ca^{2+}$ and $HCO{_3}^-$ were significant in wet season. ${\delta}^{18}O$ and ${\delta}D$ of the groundwater and lake water were plotted near LMWL (${\delta}D=8.06{\delta}^{18}O+12.5$). ${\delta}^{18}O$ and ${\delta}D$ of the lake water did not show seasonal variation. However, ${\delta}^{18}O$ and ${\delta}D$ of the groundwater were enriched in wet season compared with those in dry season because of influence of small ponds around wells where evaporation losses were slightly experienced. Redox condition of most lake water was oxidation environment in contact with the atmosphere during the study period. However, redox condition of groundwater was transitional environment in dry season and oxidation environment in wet season because of influence of contaminant such as petroleum. In some groundwater, the concentrations of $NO{_3}^-$ in some groundwater were less than 1 mg/L because of denitrification. Also, $NO{_3}^-$ showed positive correlation with $SO{_4}^{2-}$ and weak negative correlation with $HCO{_3}^-$, because of influence of denitrification.

• Journal of the Korean Society of Industry Convergence
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• v.1 no.1
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• pp.43-49
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• 1998

The SS-phpm 4HCl(N,N'-bis-[2(S)-pyrrolidinylmethyl]phenylene-l,2-diamine-4-Hydrochloride) ligand having stereospecificity has been prepared and reacted with trans-[$Co(pyridine)_4Cl_2]$Cl. The resultants are purple crystals, which are identified to be ${\Delta}$-cis-${\beta}$-[$Co(SS-phpm)Cl_2$]Cl by elemental analysis and UV/Vis- and CD-absorption spectra, The conformation of SS-phpm in ${\Delta}$-cis-${\beta}$ complex is ${\delta}$ ${\varepsilon}$ ${\lambda}$ (SSSS) for each of the five-membered chelated ring. Futhermore, according to orientation of secondary amine, total strain energy on each isomers was calculated by molecular mechanics(MM) to verify structural characterization and spectral data. As the result, the most stabilized isomer was ${\Delta}$-cis-${\beta}$(SSSS). The value of total strain energy(U) of ${\Delta}$-cis-${\beta}$(SSSS) isomer was 63.21 kcal/mol, respectively.

• Journal of the Korean Chemical Society
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• v.56 no.4
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• pp.424-430
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• 2012

Densities, viscosities, refractive indices and speed of sounds of the binary mixtures of Acetophenone with Ethylchloroacetate were measured over the entire mole fractions at (303.15, 313.15 and 323.15) K. From these experimental results, excess molar volume $V^E$, viscosity deviation ${\Delta}{\eta}$, refractive index deviation ${\Delta}n_D$, deviations in speed of sound ${\Delta}u$, deviations in isentropic compressibility ${\Delta}k_s$ and excess intermolecular free length ${\Delta}L_f$ were calculated. The viscosity data have been correlated with the equations of Grunberg and Nissan, Hind et al., Tamura and Kurata, Katti and Chaudri, Sedgwick, Krishnan-Laddha and McAllister. The thermo physical properties under study were fit to the Jouyban-Acree model. The excess values were correlated using Redlich-Kister polynomial equation to obtain their coefficients and standard deviations. It was found that in all cases, the data obtained fitted with the values correlated by the corresponding models very well. The results are interpreted in terms of molecular interactions occurring in the solution.

• Journal of Microbiology and Biotechnology
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• v.24 no.3
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• pp.401-407
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• 2014

Quorum sensing and the stringent response are well-known regulation systems for the expression of virulence genes in enterohemorrhagic Escherichia coli (EHEC). However, how these two systems interact is not well known. E. coli strains with mutations in two regulation systems, ${\Delta}luxS$ (ECM101) and ${\Delta}luxS{\Delta}relA{\Delta}spoT$ (ECM201), and the ${\Delta}luxS$ complement strain to ECM201 (ECM202) were created from EHEC O157:H7 EDL933 to investigate how the regulatory systems interact. The phenotypic changes of the mutant strains were characterized and compared with the wild type. The mutant strains exhibited no obvious growth defects, although acid resistance and cellular cytotoxicity were decreased significantly in all the mutant strains. Phenotypic characterization revealed that mutations in the stringent response system (ECM201 and ECM202) influenced the metabolic (defective utilization of arabinose and L-sorbose) and enzymatic activities (decreased trypsin activity, and increased ${\alpha}$-glucosidase activity). In contrast, the quorum sensing system mutant (ECM101) did not display these phenotypes. The motility of the quorum sensing system mutant (ECM101) was unchanged, but mutation in the stringent response system influenced the motility. Our results suggest that quorum sensing interacts with the stringent response regulation system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.11
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• pp.1167-1173
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• 2004

This paper reports the variations of varistor voltage, nonlinear exponent, leakage current, and dissipation factor against surge stress of ZnO-P $r_{6}$ $O_{11}$-CoO-C $r_2$ $O_3$-E $r_2$ $O_3$(ZPCCE)-based varistors manufactured with the variations of sintering temperature. It was found that the variations of electrical parameters against surge stressing current of 100 A/$\textrm{cm}^2$(8x20 ${\mu}\textrm{s}$) is not so large under the surge stress of 700 times. Among varistors, specially the varistor sintered at 134$0^{\circ}C$ exhibited the smallest variations, with %$\Delta$ $V_{lmA}$=+0.23%, %$\Delta$$\alpha$=+0.23%, %$\Delta$ $I_{L}$=0%, %$\Delta$tan$\delta$=-6.94%. The clamping voltage ratio( $V_{c}$/ $V_{lmA}$) of all varistors was less than 2.2.2.2.2.2.2.