• Journal of the Korean Chemical Society
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• v.37 no.7
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• pp.635-641
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• 1993

Electrochemical cell, $Pt|air(PO_2=5.3{\times}10^{-3}atm)|Zr_{0.85}Ca_{0.15}O_{1.85}|air(PO_2= 0.21atm)|Pt$, has been designed to characterize the solid electrolyte and the temperature dependence of the electromotive force (EMF) has been measured in a temperature range of 600∼1000${\circ}$C. Solid electrolyte shows pure ionic conduction of the oxygen anion. The Fe-FexO, Co-CoO, Ni-NiO, and Cu2O-CuO electrodes have been prepared by mixing the 1 : 1 mole ratio of each metal and metal oxide and then by heating at 800${\circ}$C for 6 hours. Electrochemical cells, Pt│M(s), $MO(s)|Zr_{0.85}Ca_{0.15}O_{1.85}|air(PO_2=0.21atm)|Pt$, have been designed and the temperature dependence of the EMF has also been measured in the same temperature range. The changes of the thermodynamic state functions for the formation of the metal oxides are calculated from the electromotive forces and their temperature dependences. The material properties of the oxide systems are also discussed with the function changes.

• Food Science and Preservation
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• v.22 no.1
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• pp.70-77
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• 2015

The physiological properties of water extracts from Hizikia fusiformis extracted using different extraction methods (water extraction, WE; autoclave extraction, AE; high pressure extraction, HPE) were investigated. The freeze-dried powder yields from HPE, AE and WE were 29.33, 27.84 and 23.63%, respectively. The $L^*$ and $b^*$ color values were higher in WE, while the $a^*$ color values were higher in WE and AE. The total sugar content of AE (60.14%) was higher than those of WE (47.10%), HPE (40.97%). The reducing sugar content (7.88%) and protein content (42.83%) of AE was higher than those of WE, and HPE. The uronic acid (5.04%), total free amino acid (785.19 mg/g), taurine (19.16 mg/g), aspartic acid (66.63 mg/g), asparagine (204.84 mg/g), alanine (188.87 mg/g) and ammonium chloride (243.91 mg/g) contents, however, were the highest in HPE. Additionally, the crude polysaccharide yield was higher in HPE (4.75%) than in AE and WE, and the crude saccharide (fucose, galactose, glucose, xylose and fucose) yields were higher in AE. It can be concluded that optimum conditions for the efficient extraction of Hizikia fusiformis depending on components are high pressure and a lower temperature than in the typical process.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1661-1666
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• 1999

Yungmijihwgang-Won, Yollyunggobon-Dan and Palmi-Hwan, Korea traditional prescriptions composed of oriental medical herbs, have been used successfully to improve human health and regimen. This study was designed to examine the mechanism of healthful effects of the Korea traditional prescriptions through its antioxidative potentials. Using in vitro antioxidative activity assay system such as DPPH radical quenching assay, superoxide anion radical scavenging assay and inhibition of TBARS production, three Korea traditional prescriptions were observed to have nearly the same antioxidative potentials as ascorbic acid, a well-known strong water-soluble antioxidant. Moreover, we observed reinforced antioxidative effects of these drugs in liver from mouse fed these drugs with 4 weeks. When liver homogenate was incubated with 2.2'-azobis(amidinopropane) dihydrochloride(AAPH), as a free radical initiator, we observed that oxidative damages were decreased and antioxidative potentials were increased in liver homogenate treated these drugs. However, enzymatic antioxidative system as superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase was not affected by drug administration.

• Journal of Life Science
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• v.25 no.4
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• pp.425-432
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• 2015

This study was performed to develop high-value-added biomaterials for health and beauty products. Extracts of ethanol and hot water and their subsequent organic solvent fractions were prepared from Lees of Wookukseng (LW), a commercialized Korean traditional rice wine. We investigated their activities on blood coagulation, platelet aggregation, hemolysis against human red blood cells (hRBCs), and anti-oxidation. The water content, pH and brix of the LW were 80.3%, 3.94 and 13.0°, respectively. The yield of ethanol extraction (6.62%) was 3.15 times higher than that of hot-water extraction (2.1%), and the ethyacetate fraction (EAF) of ethanol extract showed the highest content of total polyphenol (128 mg/g) among the various fractions. In anticoagulation activity assay, the EAF of ethanol extract showed a 15-fold extension in TT, PT, and aPTT, indicating that the EAFs contain various inhibitory substances against thrombin, prothrombin and coagulation factors. In anti-platelet aggregation activity assay, the butanol fraction and water residue of ethanol extract showed significant inhibition activity. The activities were comparable to aspirin, a commercial anti-thrombosis agent. The above extracts and fractions did not show hemolysis activity against hRBC up to 5 mg/ml, and had radical scavenging activity against DPPH anion, ABTS cation and nitrite. Our results suggest that the active fractions prepared from LW, which has no specific usage until now, have a high potential as novel resources for anti-thrombosis agents.

• Journal of Life Science
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• v.17 no.11
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• pp.1517-1522
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• 2007

Gap junction channels formed by two adjacent cells allow the passage of small molecules up to ${\sim}\;1\;kDa$ between them. Hemichannel (connexon or half of gap junction) also behaves as a membrane channel like sodium or potassium channels in a single cell membrane. Among 26 types of connexin (Cx), $Cx32^*43E1$ (a chimera in which the first extracellular loop of Cx32 has been replaced with that of Cx43), Cx38, Cx46, and Cx50 form functional hemichannels as well as gap junction channels. Although it is known that Xenopus oocytes express endogenous connexin 38 (Cx38), its biophysical characteristics at single channel level are poorly understood. In this study, we performed single channel recordings from single Xenopus oocytes to acquire the biophysical properties of Cx38 including voltage-dependent gating and permeation (conductance and selectivity). The voltage-dependent fast and slow gatings of Cx38 hemichannel are distinct. Fast gating events occur at positive potentials and their open probabilities are low. In contrast, slow gatings dominate at negative potentials with high open probabilites. Based on hi-ionic experiments, Cx38 hemichannel is anion-selective. It will be interesting to test whether charged amino acid residues in the amino terminus of Cx38 are responsible for voltage gatings and permeation.

• Journal of Life Science
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• v.24 no.6
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• pp.648-654
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• 2014

Grape pruning stems constitute a scarcely investigated class of byproducts with limited reports on their bioactive polyphenol content and/or industrial applications. Herein we present the outcome of our investigation on grape pruning stems extracts, concerning the assessment of their total polyphenolic content and the detailed evaluation of their antioxidant properties. Results obtained indicate that grape pruning stems are particularly rich in flavonoids and trans-resveratrol. The antioxidant activities was analyzed and expressed as electron donating ability, ABTS cation radical decolorization, hydrogen peroxide scavenging activity and superoxide anion radical scavenging activity, the antioxidant activity of Vitis labrusca L. pruning stems extracted (GPSE) was higher than that of BHA and L-ascrobic acid. The whitening and anti-wrinkle activities display an capability. Results herein grape pruning stems used as a valuable resource for the extraction of resveratrol, which would be added to functional cosmetics and food materials.

• Journal of Life Science
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• v.23 no.12
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• pp.1486-1494
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• 2013

A high protease-producing strain was isolated and identified from the digestive tract of octopus vulgaris by detecting a hydrolysis circle of protease and its activity. The strain was identified by morphology observation, biochemical experiments, and 16S rRNA sequence analysis. The protease obtained from the strain was purified by a three-step process involving ammonium sulfate precipitation, carboxy methyl-cellulose (CM-52) cation-exchange chromatography, and DEAE-Sephadex A50 anion-exchange chromatography. The properties of protease were characterized as well. The strain Bacillus sp. QDV-3, which produced the highest activity of protease, was isolated. On the basis of the phenotypic and biochemical characterization and 16S rRNA gene-sequencing studies, the isolate was identified as follows: domain: Bacteria; phylum: Firmicutes; class: Bacilli; order: Bacillales; family: Bacillaceae; and genus: Bacillus. The isolate was shown to have a 99.2% similarity with Bacillus flexus. A high active protease designated as QDV-E, with a molecular weight of 61.6 kDa, was obtained. The enzyme was found to be active in the pH range of 9.0-9.5 and its optimum temperature was $40^{\circ}C$. The protease activity retained more than 96% at the temperature of $50^{\circ}C$ for 60 min. Phenylmethylsulfonyl fluoride (PMSF) inhibited the enzyme activity, thus confirming that this protease isolated from Bacillus sp. QDV-3 is an alkaline serine protease. Metal ions, $Mn^{2+}$ and $Mg^{2+}$, were determined to enhance the protease activity, whereas $Ba^{2+}$, $Zn^{2+}$, and $Cu^{2+}$ were found to inactivate the enzyme.

• The Korean Journal of Ecology
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• v.27 no.6 s.122
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• pp.347-353
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• 2004

This study was carried out to analyze pH, Electrical conductivity(EC), cation and anion on rainfall and throughfall raining at industrial area(Onsan and Nongso of Ulsan city), suburban area(Myeongsek-myeon of Jinju city) and rural area(Haman and Changyoung-gun), and to investigate $SO_2\;and\;NO_2$ concentration in the air of industrial area and rural area, and to survey degree of decline of Pinus thunbergii growing at each area. The rainfall pH was higher than the throughfall pH at the all surveyed areas. The rainfall pH and throughfall pH was $4.76{\sim}5.15\;and\;4.64{\sim}4.98,\;4.95{\sim}5.30\;and\;4.87{\sim}5.13,\;5.29{\sim}5.76\;and\;5.12{\sim}5.73$ at the industrial area, suburban area and rural area, respectively. The EC of rainfall and throughfall was $13.64{\sim}17.22\;and\;41.60{\sim}103.59,\;4.18{\sim}8.65\;and\;17.02{\sim}23.89,\;4.09{\sim}6.65\;and\;13.75{\sim}21.44$ at the industrial area, suburban area and rural area, respectively. Generally EC at the industrial area was higher than those of suburban area and rural area. In the correlation analysis among Degree of decline on Pinus thunbergii and ingredients of rainfall, it showed that there was a negative correlation between Degree of decline and pH. There was a positive correlation between pH and $Cl^-$ respectively.

• Journal of Environmental Science International
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• v.19 no.5
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• pp.565-575
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• 2010

This study is mainly focused on micellar effect of cetylpyridinium chloride(CPyCl) solution including alkylbenzimidazole(R-BI) on dephosphorylation of diphenyl-4-nitrophenylphosphinate(DPNPIN) in carbonate buffer(pH 10.7). The reactions of DPNPIN with R-BI$^{\ominus}$ are strongly catalyzed by the micelles of CPyCl. Dephosphorylation of DPNPIN is accelerated by BI$^{\ominus}$ ion in $10^{-2}M$ carbonate buffer(pH 10.7) of $4{\times}10^{-3}M$ CPyCl solution up to 100 times as compared with the reaction in carbonate buffer by no BI solution of $4{\times}10^{-3}M$ CPyCl. The value of pseudo first order rate constant($k^m_{BI}$) of the reaction in CPyCl solution reached a maximum rate constant increasing micelle concentration. Such rate maxima are typical of micellar catalyzed bimolecular reactions. The reaction mediated by R-BI$^{\ominus}$ in micellar solutions are obviously slower than those by BI$^{\ominus}$, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of R-BI$^{\ominus}$ in Stern layer of micellar solution. The surfactant reagent, cetylpyridinium chloride(CPyCl), strongly catalyzes the reaction of diphenyl-4-nitrophenylphosphinate(DPNPIN) with alkylbenzimidazole (R-BI) and its anion(R-BI$^{\ominus}$) in carbonate buffer(pH 10.7). For example, $4{\times}10^{-3}M$ CPyCl in $1{\times}10^{-4}M$ BI solution increase the rate constant ($k_{\Psi}=1.0{\times}10^{-2}sec^{-1}$) of the dephosphorylation by a factor ca.14, when compared with reaction ($k_{\Psi}=7.3{\times}10^{-4}sec^{-1}$) in $1{\times}10^{-4}M$ BI solution(without CPyCl). And no CPyCl solution, in $1{\times}10^{-4}M$ BI solution increase the rate constant ($k_{\Psi}=7.3{\times}10^{-4}sec^{-1}$) of the dephosphorylation by a factor ca.36, when compared with reaction ($k_{\Psi}=2.0{\times}10^{-5}sec^{-1}$) in water solution(without BI). This predicts that the reactivities of R-BI$^{\ominus}$ in the micellar pseudophase are much smaller than that of BI$^{\ominus}$. Due to the hydrophobicity and steric effect of alkyl group substituents, these groups would penetrate into the core of the micelle for stabilization by van der Waals interaction with long alkyl groups of CPyCl.

• Korean Chemical Engineering Research
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• v.43 no.3
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• pp.352-359
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• 2005

This work has studied the changes of pH in both of anodic and cathodic chambers of a divided cell due to the electrolytic split of water during the ammonia decomposition to nitrogen, and has studied the continuous decomposition characteristics of ammonia in a multi-cell stacked electrolyzer. The electrolytic decomposition of ammonia was much affected by the change of pH of ammonia solution which was caused by the water split reactions. The water split reaction occurred at pH of less than 8 in the anodic chamber with producing proton ions, and occurred at pH of more than 11 in the cathodic chamber with producing hydroxyl ions. The pH of the anodic chamber using an anion exchange membrane was sustained to be higher than that using a cation exchange membrane, which resulted in the higher decomposition of ammonia in the anodic chamber. By using the electrolytic characteristics of the divided cell, a continuous electrolyzer with a self-pH adjustment function was newly devised, where a portion of the ammonia solution from a pHadjustment tank was circulated through the cathodic chambers of the electrolyzer. It enhanced the pH of the ammonia solution fed from the pH-adjustment tank into the anodic chambers of the electrolyzer, which caused a higher decomposition yield of ammonia. And then, based on the electrolyzer, a salt-free ammonia decomposition process was suggested. In that process, ammonia solution could be continuously decomposed into the environmentally-harmless nitrogen gas up to 83％, when chloride ion was added into the ammonia solution.