• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.161-171
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• 1997

Anodic regeneration of PCB enchant and cathodic deposition of copper using electrochemical method has been studied. Cu(I)/Cu(II) concentration ratio as a function of Cu(I) oxidation at the anode was measured from the potential difference between platinum and Ag/AgCl/4M KCl electrodes. Chlorine gas evolution was minimized by maintaining Cu(I) concentration above a specific concentration and using non-porous graphite electrode. Dendritic copper deposition was observed at the cathode and the optimum conditions for Cu deposition was identified as the current density of $360mA/cm^2$, and copper concentration of 12 g/l. Titanium was the most effective cathode material which showed a higher current efficiency and copper recovery. The current efficiency decreased with increasing temperature, but the highest power efficiency was achieved at $50^{\circ}C$.

• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.407-411
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• 1999

Studies have been carried out on the fabrication of PPy/GC and PPy/Pt electrode modified with polypyrrole film and determination of Cr(VI) by using 3-electrode system with modified electrodes. Modified electrodes were able to easily fabricated by cyclic voltammetry scanned from +1.0V to -1.0V(vs. Ag/AgCl) at 50 mV/sec. Film thickness could be controlled at same condition by the number of cycling up to 26 times. Reduction behaviour of Cr(VI) at PPy/GC electrode could be seen at wide potential ranges from +0.6V to -0.5V(vs. Ag/AgCl), and maximum reduction peak potential of the ion was observed at -0.25V(vs.Ag/AgCl). Calibration graph at its potential was linear from 0.1 ppm to 80.O ppm. Slope factor and relative coefficient were 1.75 mA/ppm and 0.998, respectively. Reduction behaviour of Cr(VI) at PPy/Pt electrode was similar to PPy/GC electrode, Calibration graph was linear from l.0 ppm to 60.0 ppm. Slope factor and relative coefficient were 0.5mA/ppm and 0.923, respectively. But PPy/GC modified electrode had about 3 times higher sensitivity than PPy/Pt modified electrode. Reduction behaviour of Cu(II), As(IlI), Pb(II), and Cd(II) couldn't be seen at PPy/GC electrode,Its metals had not lnterfered with Cr (VI) determination.

• Applied Biological Chemistry
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• v.14 no.1
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• pp.59-97
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• 1971

As a study on the cellulase of Myriococcum albomyces the culture media for enzyme formation and properties of its crude preparation were investigated and the crude enzyme preparation was further fractionated. The results are summarized as follows: 1. Wheat bran solid culture produced stronger activities of cellulase than rice bran or defatted soy bean meal solid culture. 2. Shaking culture with wheat bran, rice bran or defatted soy bean meal produced higher cellulase activities than solid culture with the corresponding media. 3. The enzyme formation was higher at $45^{\circ}C$ than at $37^{\circ}C$ or $50^{\circ}C$ regardless of the kind of culture medium. 4. The formation of CMCase activity was more promoted by organic nitrogen source than inorganic nitrogen source. 5. The formation of cellulase activities were increased 1.5 to 3.0-fold by adding CMC, Avicel or cellulose powder as an inducer into 5% wheat bran basal medium. 6. Cellulase production using a tank culture procedure with addition of CMC or Avicel as an inducer was the highest at fifth day and thereafter decreased slightly. 7. The crude enzyme preparation showed pH optimum in 4.0 to 4.5, and pH stability in the range of 3.5 to 8.0. Optimum temperature for the activity was $65^{\circ}C$ which was higher than among other cellulases and it was stable at $60^{\circ}C$ for 120 minutes. 8. Dialyzed crude enzyme was activated by $Ca^{++}$ and $Mg^{++}$, but inhibited by $Hg^{++}$, $Cu^{++}$ and $Ag^{+}$. 9. Four different types of cellulase, i. e., fraction I, fraction II-a, fraction II-b, and fraction III were purified from the culture filtrate of Myriococcum albomyces through a sequence of ammonium sulfate fractionation, and elution chromatography on DEAE-Sephadex A-25, Amberlite CG-25 type 2 and hydroxyapatite columns. 10. These four cellulase fractions were showed to be homogenous by electrophoresis and ultracentrifugation and also gave a typical ultraviolet absorption spectrum of protein. 11. Four purified fraction showed different specificity toward substrates, fraction I has a stronger activity toward Avicel, cellulose powder, and gauze than that of other cellulase fractions. Fraction II-a had a powerful activity toward cellobiose but it was almost inactive agaisnt fibrous cellulose contrary to fraction I. On the contrary, the main component fraction II-b had a fairly higher activity on CMC and Avicel. Activity of fraction II-b toward cellobiose was about one-third of that of fraction II-a and activity on Avicel was lower than that of fraction I. Fraction III had a more powerful activity in decreasing viscosity of CMC. 12. Final hydrolysis products of fibrous cellulose by each fraction were cellobiose and glucose. Whereas oligosaccharides were predominant in the early stage of hydrolysis, prolonged reaction produced more glucose than cellobiose. Fraction I and fraction II-a acted synergically on Avicel. 13. Optimum pH for the activities of cellulase fraction I, fraction II-a, fraction II-b and fraction III were found to be 5.5, 5.0, 4.0 and $4.0{\sim}4.5$, respectively. These fractions were found to be stable in the range of pH $3.0{\sim}7.5$. 14. Optimum temperature for the activities of fraction I, fraction II-a, fraction II-b, and fraction III were $50^{\circ}C$, $55^{\circ}C$, $60^{\circ}C$ and $55^{\circ}C$, respectively. No less of activity was found by heating 120 minutes at $55^{\circ}C$ and fraction II-a was more stable than the others at $60^{\circ}C$. 15. Fraction I and fraction II-b were activated by $Ca^{++}$ and $Mg^{++}$ but inhibited by $Hg^{++}$ and $Ag^{+}$.

• Korean Journal of Microbiology
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• v.39 no.4
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• pp.223-229
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• 2003

The purpose of this work was to perform the characterization of NAD(P)H-nitroreductase isolated from Stenotrophomonas sp. OK-5 capable of degrading 2,4,6-trinitrotoluene (TNT). Initially, NADP(H)-nitroreductase by a series of purification processes including ammonium sulfate precipitation, DEAE-sepharose, andQ-sepharose was prepared. From samples harvested from fraction collector, three different fractions (I, II & III)having the enzyme activity of NAD(P)H-itroreductase were detected. Specific activities of three fractions I, II,and III of NAD(P)H-nitroreductase were determined to approximately 5.06 unit/mg, 4.95 unit/mg and 4.86 unit/mg, and concentrated to 10.5, 9.8, and 8.9-fold compared to crude extract, respectively. Among these three fractions,the fraction I of NAD(P)H-nitroreductase demonstrated the highest specific activity in this experiment. Several factors affecting on the enzyme activity of NAD(P)H-nitroreductase (fractions I, II & III) were investigated.The optimum temperature of all NAD(P)H-nitroreductase (fractions I, II & III) was 30oC, and the optimal pH was approximately 7.5. Metal ions such as Ag+, Cu2+, Hg2+ inhibited approximately 80% enzyme activity of all NAD(P)H-nitroreductase, and the enzyme activities were decreased about 30-40% inhibition in the presence of Mn2+ or Ca2+. However, Fe3+ showed stimulatory effect on the enzyme activity. The molecular weights of NAD(P)H-nitroreductase (fractions I, II & III) were measured about 27 kDa on the SDS-PAGE.

• Biomolecules & Therapeutics
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• v.3 no.4
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• pp.279-287
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• 1995

This study examined the anti-cancer effects of diallyl sulfide(DAS) and/or diallyl disulfide(DDS), major components of garlic oil, with the DEN-PH model in rats, by the numbers and areas per cm$^2$ of induced glutathion S-transferase placental form(GST-P) positive foci and silver-stained nucleolar organizer regions(Ag-NORs) counts per nuclei in liver as indicator. Sprague-Dawley(SD) rats were given the diethylnitrosamine(DEN, 200 mg/kg, i.p.) as initiator and 2 weeks later, in experiment 1, rats were treated with DAS(200 mg/kg, i.g.) and/or DDS(50 mg/kg, i.g.) for 6 weeks, respectively and concomitantly and also were given the same dose of DAS and/or DDS prior to DEN treatment for 2 weeks, and in experiment II, rats were treated with potential cancer promoter, 2-acetylaminofluorene (2-AAF, 20 mg/kg, i.g.). The DAS and/or DDS were treated prior to 2-AAF for 8 weeks, respectively and concomitantly. Then the anti-promoting effects of DAS and/or DDS were assessed. All rats were subjected to the two-thirds partial hepatectomy(PH) at week 3 and sacrificed at week 8. In experiment I, DAS and/or DDS treatment only prior to DEN showed inhibition of the development of GST-P positive foci. In experiment II, DAS and/or DDS treatment prior to 2-AAF promotion showed obvious inhibition of the development of GST-P positive foci in numbers and areas and AgNORs counts. In conclusion, We found DAS and/or DDS had the preventive effects on the hepatocarcinogenesis in rats and the concomitant treatment had some additive effects compared with the each treatment and AgNORs counts correlated well with the preneoplastic hepatic lesion.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.5
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• pp.470-482
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• 2021

Purpose: We investigated the relationship between sonographic measurements of fatty liver and body mass index standard deviation score (BMI-Z score), abdominal wall fat thickness (AWFT), and serum biochemical parameters in childhood obesity. Methods: Anthropometric, laboratory, and ultrasonography data were obtained from 174 children with BMI-Z score >1. After the qualitative grading of hepatosteatosis (grades 0-3), the quantitative liver-kidney echogenicity ratio (LKER) was calculated using a software tool. Groups according to sex, age (AG-I to AG-III), BMI-Z score (BMG-I to BMG-III), and hepatosteatosis degree (HS-I and HS-II) were formed. The differences and distributions of the variables were statistically analyzed and compared among the groups. Results: Serum transaminase and glucose levels showed a positive correlation with LKER, whereas the HDL level showed a negative correlation. BMI-Z score and AWFT showed a positive correlation with fasting insulin level and HOMA-IR value. LKER was significantly higher in girls than in boys (p=0.008). In the AG-I group (age 3-8.9 years), the BMI-Z score was significantly higher, whereas AWFT was significantly lower than in the other age groups (p<0.001). The cutoff point of LKER for predicting grade 2 or higher steatosis (HS-II group) was determined to be 1.83. Cardiovascular disease risk was significantly higher in the HS-II group (p=0.035). Conclusion: As a valuable quantitative measurement tool, LKER can be used for the sonographic screening of fatty liver. AWFT, on the basis of its correlation with fasting insulin level and HOMA-IR value, may be a useful sonographic parameter in the management of childhood obesity.

• Journal of Preventive Medicine and Public Health
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• v.17 no.1
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• pp.203-210
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• 1984

Primary screening test for serum HBsAg by RPHA from 4,805 persons who were clinically well through preemployment examination for the period of one calendar year of 1983 revealed 476 (9.9%) positive individual carriers. There were no significant differences in distribution of positives of serum HBsAg by age group, profession, or province area. Among positives of serum HBsAg, 356 (74.8%) showed normal findings and 120 (25.2%) showed abnormal findings in liver function test, respectively. Radioimmunoassay was done in 169 positives of HBsAg and RIA detected 10 negative persons who were positive by RPHA revealing 5.9% of false positive rate and 94.1% of sensitivity of RPHA. In RIA profile of HBV markers, pattern I (HBsAg+, Anti-HBe+) was 46.6%, pattern II (HBsAg+, HBeAg+) was 33.3%, pattern III (HBsAg+only) was 18.3%, pattern IV (HBsAg+, HBeAg+, Anti-HBs+) was 1.3%, pattern V (HBsAg+, HBeAg+, Anti-HBe+) was 0.6%, respectively. There were no positives of HBsAg among 10 persons who were negatives of HBsAg by RIA.

• Economic and Environmental Geology
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• v.28 no.1
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• pp.9-17
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• 1995

The Kamkye Cu-Pb-Zn-Au-Ag deposits occur as quartz veins that filled fault-related fractures of NW system developed in the Cretaceous Gyeongsang basin. Three major stages of mineral deposition are recognized: (1) the stage I associated with wall rock alteration, such as sericite, chlorite, epidote and pyrite, (2) the early stage II of base-metal mineralization such as pyrite, hematite, and small amounts of sphalerite and chalcopyrite. and the middle to late stage II of Cu-As-Sb-Au-Ag-S mineralization, such as sphalerite, chalcopyrite, galena with tetrahedrite, tennantite, pearceite, Pb-Bi-Cu-S system, argentite and electrum. (3) the stage III of supergene mineralization, such as covellite, chalcocite and malachite. K-Ar dating of alteration sericite is a late Cretaceous ($74.0{\pm}1.6Ma$) and it may be associated with granitic activity of nearby biotite granite and quartz porphyry. Fluid inclusion data suggest a complex history of boiling, cooling and dilution of ore fluids. Stage II mineralization occurred at temperatures between 370 to $220^{\circ}C$ from fluids with salinities of 8.4 to 0.9 wt.% NaCl. Early stage II($320^{\circ}C$, 2.0 wt.% NaCl) may be boiled due to repeated fracturing which opened up the hydrothermal system to the land surface, and which resulted in a base-metal sulfide. Whilst the fractures were opened to the surface, mixing of middle-late stage II ore fluids with meteoric waters resulted in deposition of Cu-As-Sb-Au-Ag minerals from low temperature fluids(${\leq}290^{\circ}C$). Boiling of ore fluids may be occured at a pressure of 112 bar and a depth of 412 m. Equilibrium thermodynamic interpretation of sphalerite-tetraherite assemblages in middle stage II indicates that the ore-forming fluid had log fugacities of $S_2$ of -6.6~-9.4 atm.

• Microbiology and Biotechnology Letters
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• v.20 no.6
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• pp.619-624
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• 1992

Tn5 lac 삽입으로 채소입고병원균에 길항력이 약화된 T-67 및 고추역병균과 참깨역병균에 길항력이 약화된 T-81의 Tn5 lac 유전자 일부와 오른쪽 말단에 있는 길항관련 유전자의 flanking sequence가 cloning된 pAG67 및 pAG81 clone을 선발하였고, pAG67 및 pAG81 clone된 길항관련 유전자의 flanking sequence를 야생 길항균 Pseudomonas maltophilia B-14의 DNA를 probe로 사용하여 Southern hybridization으로 확인하였으며, 제한효소 지도를 작성하여 8Kb 및 4Kb 크기의 flanking sequence가 cloning되었음을 확인하였다. pAG6 및 pAG81의 flanking sequence를 EcoRi-BglII와 EcoRI-MpaI으로 분리하여 유전자 은행으로부터 길항관련 유전자가 cloning된 cosmid clone 7개주를 선발하였다.

• Journal of the Korean Magnetic Resonance Society
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• v.20 no.3
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• pp.76-81
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• 2016

Copper is an elemental ion in living organisms. CopP from Helicobacter Pylori (HpCopP) is a copper(I)-binding protein and was suggested as regulator of copper metabolism in vivo. Previously, the metal binding property of HpCopP for Ag(I), Cu(I), and Cu(II) as well as the tertiary structure of HpCopP was shown. In this study, the dynamic profiles of HpCopP depending on metal binding were studied using ${^1H}-^{15}N$ steady-state NOE analysis. The heteroNOE experiment was performed for apo-CopP or metal-bound CopP. The obtained NOE values were analyzed and compared to figure out the effect of metals on the structural flexibility of HpCopP. As a result, Ag(I) and Cu(I) ions improved the rigidity of the structure while Cu(II) ion increased the flexibility of the structure, suggesting the oxidation of the CXXC motif decreases the structural stability of HpCopP.