• 한국동물학회지
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• 제29권2호
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• pp.141-158
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• 1986

흰쥐를 실험재료로 그 적혈구에서 glutathione peroxidase를 $(NH_4)_2SO_4$ 침전법, Sephadex filtration column, DEAE-sephadex column chromatogrgphy하여 순화시키고 이것의 성질을 연구하였으며, 간에서 이 효소의 작용부위를 조직화학적 처리를 하여 전자현미경으로 관찰한 결과는 다음과 같다. 1. Glutathione peroxidase는 약 33.5배 순화되었다. 2. Crude glutathione peroxidase의 최적온도는 $40^\\circC$이며, 반응 최적 pH는 7.5였다. 3. 이 효소는 $30^\\circC$에서 가장 안정되었으며 glutathione농도 변화에 대한 Km값은 8.5 mM, 최대 반응속도는 15.6 $\\mu$moles/min이었고, $H_2O_2$ 농도변화에 대한 Km값은 40 $\\mu$M이며, 최대 반응속도는 10.5 $\\mu$moles/min이었다. 4. 이 효소의 분자량은 약 90,000정도로 측정되었다. 5. 쥐의 간에서 이 효소의 활성부위는 microbody에 국한되며 간소염의 주변주에서 그 활성이 크게 나타났다. 6. 조직화학적 방법으로 나타난 반응산물은 직경 $2.0\\sim0.7 \\mum$ 정도의 원형으로 그 경계막은 뚜렷하지 않았다.

• 자원환경지질
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• 제27권3호
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• pp.219-229
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• 1994

The Sangra Pb-Zn deposit is located in the Gampo area. Most Cretaceous sedimentary rocks and Paleogene felsic intrusives in the study area have experienced intense propylitization. Such propylitization and Pb-Zn mineralization in ore veins are involved with the fluid having very low oxygen isotopic composition.Sulfurisotopic equilibrium temperature during the main Pb-Zn mineralization (late stage I) is calculated as $T=275^{\circ}{\sim}295^{\circ}C$. Oxygen and sulfur fugacity in late stage I fluid is estimated as $logfO_2=-34.4{\sim}-29.1$ and $logfS_2=-12.0{\sim}-8.2$ bars. It is inferred that the sulfur isotopic composition oflate stage I fluid was very high such as ${\delta}^{34}S_{{\Sigma}S}=+22.4{\sim}+22.5$‰ and the origin of sulfur was ocean water sulfate. Oxygen and hydrogen isotopic composition of water in ore-forming fluid was gradually increased and more abundantly affected by ocean water from early to late mineralization stage as follows; (late stage I) ${\delta}^{18}O_{H2O}=-7.2{\sim}-1.1$‰, ${\delta}D_{H2O}=-87{\sim}-84$‰, (stage II) ${\delta}^{18}O_{H2O}=-2.4{\sim}-0.8$‰, ${\delta}D_{H2O}=-39{\sim}-21$‰ (stage III) ${\delta}^{18}O_{H2O}=+0.7{\sim}+12.6$‰, ${\delta}D_{H_2O}=-49{\sim}-42$‰. The pH in ore-forming fluid was about 4.7 during late stage I and is thought to have been gradually decreased from late stage I to stage II mineralization.

• Applied Biological Chemistry
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• 제30권3호
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• pp.219-226
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• 1987

녹두의 자엽에서 peroxidase isozyme을 $(NH_4)_2SO_4$ 침전, Sephadex G-75, DEAE-cellulose 및 DEAE-Sephadex A-50 column chromatography 등으로 63배 정제하여 그 특성 및 결정구조를 조사하였다. Isozyme C는 Rm 값이 0.24로서 분자량이 50,000 dalton인 단량체였다. 이 효소의 반응 최적 PH는 o-dianisidine에 대하여 5.0, guaiacol에 대해서는 6.0, 반응 최적온도는 $70^{\circ}C$였으며 열에 대해서도 비교적 안정하였다. o-dianisidine과 guaiacol에 대한 Km 값은 각각 0.11mM, 60.98mM이었으며, isozyme C에 대한 기질과 cyanide는 경쟁적 저해형식을 나타내었다. Isozyme C는 평면상 직사각형의 결정구조를 하고 있었다.

• 대한화학회지
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• 제21권4호
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• pp.276-283
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• 1977

산성용액중에서 백금음극을 사용하여 중크롬산이온의 환원을 전위주사법 및 정전위전해에 의하여 검토하였다. 지지전해질로서 황산나트륨(pH 1.5∼4.0)을 사용한 비완충용액중의 중크롬산칼륨의 분극곡선은 3단파가 생기며 첫째파 및 둘째파의 파고는 각각 크롬(Ⅵ)농도 및 수소이온의 활동도에 비례하나 셋째파는 어느 것에도 비례하지 않았다. 첫째 및 둘째 peak이 전류는 전위주사속도(${\nu}$)에 비례하나 셋째 peak는 50mV/sec이하의 늦은 주사속도에서 ${\nu}^{1/2}$에 비례하였다. 정전위전해에 의하면, 크롬(Ⅵ)의 환원은 셋째 peak보다 더 base이고 초기 pH가 약 2.3 이상이 되면 완전히 억제되었다. 그러므로 이 세 peak는 각각 $Cr_2O_7^{\to}Cr^{3+},\;2H^+{\to}H_2$ 및 음극피막의 형성으로 간주하였다.

• 한국광물학회지
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• 제29권3호
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• pp.113-122
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• 2016

산화대 금 광석에 존재하는 적철석을 암모니아 용액을 이용하여 제거하여 금과 은의 회수율을 향상시키고자 하였다. 산화대에는 석영, 적철석, 백운모가 존재하고 있으며, 적철석은 수성기원으로 형성되었다. 다양한 변수에 대하여 암모니아 용출실험을 수행한 결과, Fe 최대 용출 인자는 $-45{\mu}m$ 입도 크기, 1.0 M의 황산 농도, 5.0 g/l의 황산암모늄 농도 그리고 2.0 M의 과산화수소 농도일 때였다. 이 암모니아 용출용액으로부터 침철석이 침전-형성되는 것을 확인하였으며, 고체-잔류물에서 Fe-제거량이 증가할수록 Au와 Ag 회수율이 증가하였다.

• 상하수도학회지
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• 제25권2호
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• pp.223-230
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• 2011

An electrolytic oxidation process was applied to remove odorous compounds from non-point odor sources including wastewater pipelines and manholes. In this study, a distance between the anode and the cathode of the electrolytic process was varied as a system operating parameters, and its effects on odor removal efficiencies and reaction characteristics were investigated. Odor precursors such as sediment organic matters and reduced sulfur/nitrogen compounds were effectively oxidized in the electrolytic process, and a change in oxidation-reduction potential (ORP) indicated that an stringent anaerobic condition shifted to a mild anoxic condition rapidly. At an electrode distance of 1 cm and an applied voltage of 30 V, a system current was maintained at 1 A, and the current density was 23.1 $mA/cm^{2}$. Under the condition, the removal efficiency of hydrogen sulfide in gas phase was found to be 100%, and 93% of ammonium ion was removed from the liquid phase during the 120 minute operating period. Moreover, the sulfate ion (${SO_4}^{2-}$) concentration increased about three times from its initial value due to the active oxidation. As the specific power consumption (i.e., the energy input normalized by the effective volume) increased, the oxidation progressed rapidly, however, the oxidation rate was varied depending on target compounds. Consequently, a threshold power consumption for each odorous compound needs to be experimentally determined for an effective application of the electrolytic oxidation.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2001년도 춘계학술발표논문집
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• pp.18-25
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• 2001

A new wood-degrading fungus Trichophyton rubrum LKY-7 secretes a high level of laccase in a glucose-peptone liquid medium. The production of laccase by the fungus was barely induced by 2,5-xylidine. The laccase has been purified to homogeneity through three chromatography steps in an overall yield of 40%. The molecular mass of the purified laccase was about 65 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified laccase had the distinct blue color and had basic spectroscopic features of a typical blue laccase: two absorption maxima at 278 and 610 nm and a shoulder at 338 nm. The N-terminus of the laccase has been sequenced, revealing high homology to laccases from wood-degrading white-rot fungi such as Ceriporiopsis subvermispora. The enzyme had a "low" redox potential (0.5 V vs normal hydrogen electrode), yet it was one of the most active laccases in oxidizing a series of representative substrates/mediators. Compared with other fungal laccases, the laccase has a very low Km value with ABTS [2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid] as a substrate and a very high Km value with violuric acid as a substrate. The laccase has the isoelectric point of 4.0. The laccase had very acidic optimal pH values (pH 3-4) while it was more stable at neutral pH than at acidic pH. The laccase oxidized hydroquinone faster than catechol and pyrogallol. The oxidation of tyrosine by the laccase was not detectable under the reaction conditions. The laccase was strongly inhibited by sodium azide and sodium fluoride. fluoride.

• 한국광물학회지
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• 제26권3호
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• pp.139-150
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• 2013

황철석 시료로부터 Fe를 효과적으로 용출시키기 위하여 마이크로웨이브 에너지와 암모니아 용액을 적용하였다. 황철석을 마이크로웨이브에 60분 동안 노출시키자 적철석과 자류철석으로 상변환되었다. 그리고 암모니아 용액에 의하여 Fe가 최대로 용출되는 마이크웨이브 노출시간은 60분이였다. Fe 용출율이 99% 이상으로 나타나는 시료와 마이크로웨이브 노출 조건은 325-400 mesh의 황철석 시료와 60분에서였다. 그리고 암모니아 용출 조건은 0.3 M의 황산, 2.0 M의 황산암모늄 그리고 0.1 M의 과산화수소 농도에서였다. 고체-잔류물에 대하여 XRD 분석을 수행한 결과 황철석, 적철석 그리고 자류철석은 암모니아 용액에 의하여 완전히 제거되었지만 석영은 제거되지 않았다.

• 한국식품과학회지
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• 제19권6호
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• pp.506-514
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• 1987

밤(생율(生栗))으로 부터 peroxidase를 $(NH_4)_2SO_4$에 의한 염석 및 DEAE-cellulose column chromatography, sephadex G-100 column chromatography, HPLC방법으로 정제하였으며 정제도는 조효소에 비하여 65.3배였고, HPLC로 측정한 밤 peroxidase 분자량은 35,000으로 추정되었다. sephadexG-100 column chromatography 후 얻은 밤 peroxidase의 작용최적 pH는 5.0이었고, 작용최적 온도는 $50^{\circ}C$이었으며 $80^{\circ}C$에서 1.73분 열처리할 때 90%의 효소가 불활성화되었다. 본 효소는 OPDA 및 PPDA와 같은 방향족 amine류에 높은 활성을 나타내었다. OPDA와 $H_2O_2$에 대한 Km치는 각각 2.6mM과 10mM이었고, 저해작용은 L-ascorbic acid 와 sodium L-ascobate가 가장 컸으며, $Ca^{++}$과 $Ba^{++}$은 1mM과 5mM에서 현저히 효소활성을 증가시켰다.

• Macromolecular Research
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• 제12권4호
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• pp.367-373
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• 2004

We have developed a rigorous heat treatment method to improve the biocompatibility of chitosan as a tissue-engineered scaffold. The chitosan scaffold was prepared by the controlled freezing and lyophilizing method using dilute acetic acid and then it was heat-treated at 110$^{\circ}C$ in vacuo for 1-3 days. To explore changes in the physicochemical properties of the heat-treated scaffold, we analyzed the degree of deacetylation by colloid titration with poly(vinyl potassium sulfate) and the structural changes were analyzed by scanning electron microscopy, Fourier transform infrared (FT-IR) spectroscopy, wide-angle X-ray diffractometry (WAXD), and lysozyme susceptibility. The degree of deacetylation of chitosan scaffolds decreased significantly from 85 to 30% as the heat treatment time increased. FT-IR spectroscopic and WAXD data indicated the formation of amide bonds between the amino groups of chitosan and acetic acids carbonyl group, and of interchain hydrogen bonding between the carbonyl groups in the C-6 residues of chitosan and the N-acetyl groups. Our rigorous heat treatment method causes the scaffold to become more susceptible to lysozyme treatment. We performed further examinations of the changes in the biocompatibility of the chitosan scaffold after rigorous heat treatment by measuring the initial cell binding capacity and cell growth rate. Human dermal fibroblasts (HDFs) adhere and spread more effectively to the heat-treated chitosan than to the untreated sample. When the cell growth of the HDFs on the film or the scaffold was analyzed by an MTT assay, we found that rigorous heat treatment stimulated cell growth by 1.5∼1.95-fold relative to that of the untreated chitosan. We conclude that the rigorous dry heat treatment process increases the biocompatibility of the chitosan scaffold by decreasing the degree of deacetylation and by increasing cell attachment and growth.