• Journal of Life Science
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• v.13 no.6
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• pp.849-855
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• 2003

Nitric oxide (NO) plays an important role as a signaling molecule in the proliferation of placenta trophoblasts. In this study, we investigated the effect of NO on the activation of phospholipase C (PLC) in BeWo cells, choriocar-cinoma cell line. Sodium nitroprusside (SNP), an agent to produce NO spontaneously in cells, alone increased $［^3H］$ thymidine incorporation of BeWo cells, indicating NO stimulates proliferation of the cells. NO-induced proliferation of BeWo cells was blocked by U73122, an inhibitor of PLC, suggesting that NO-induced PLC activation is involved in the cell proliferation. NO also stimulated extracellular signal-regulated kinase (ERK) in BeWo cells, indicated by increased phosphorylation of ERK1/2 in Western blotting using anti-phospho-ERK1/2 antibody. NO-induced phos-phorylation of ERK1/2 was not abrogated by U73122. $PLC\gamma_1$l but not$PLC\gamma_2$ was tyrosine phosphorylated by SNP in immunoprecipitation assay using anti-$PLC\gamma_1$/$PLC\gamma_2$ antibodies, and SNP-induced phosphorylation of $PLC\gamma_1$ was abrogated by pre-treatment of cells with genistein and PD98059, indicating that NO induced-phosphorylation of $PLC\gamma_1$ is mediated by ERK. These results suggest that NO stimulates the proliferation of BeWo cells through ERK and $PLC\gamma_1$.

• Journal of Life Science
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• v.24 no.6
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• pp.603-611
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• 2014

The lectins were separated from Korean and Chinese mung bean seeds finally via chromatography using Sephadex G-100 and their biochemical features were studied and compared. They showed no hemagglutination with human red blood cells regardless of trypsin treatment and showed hemagglutination with only trypsin treated rabbit red blood cells. The molecular weights of two lectins were identified as 54 kDa and 28 kDa by SDS-PAGE. It was found that while the optimal reaction temperature of the lectin from Korean mung bean was $60^{\circ}C$, that of the lectin from Chinese mung bean seeds was $50^{\circ}C$. It was found also that the most thermal stable temperature of the seed lectin from Korean mung bean seeds was $50^{\circ}C$ and the lectin from Chinese mung bean was $40-50^{\circ}C$. The lectin from Korean mung bean seeds showed the highest activity at pH 3.2 and the lectin from Chinese mung bean showed the highest activity at pH 6.2. It was identified that when treating a denaturant, thiourea and guanidine-HCl resulted in no hemagglutination, so they induced denaturalization. It was identified also that there was no hemagglutination with urea, so it did not induced denaturalization. They showed no septicity to 6 types of carbohydrates including D-glucose. In addition, the lectins from the two mung bean seed had specificity to metal ions.

• Membrane Journal
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• v.19 no.4
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• pp.310-316
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• 2009

The degradation characteristics of cross-linked lactide/hyaluronic acid (LA/HA) membranes were investigated for purpose of applying to tissue engineering. The lactide/hyaluronic acid cross-linked with 1,3-butadiene diepoxide (BD) and 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) was degradated in deionized water in water bath at $37^{\circ}C$. As the LA/HA mole ratio or crosslinking agent concentration decreased, the degradation rate of the crosslinked membranes increased. In order to investigate the structure change of the membrane in the degradation process, the control sample and 3, 6, 9 days-degradated samples were analysed by the nuclear magnetic resonance spectroscopy. In case of the membranes crosslinked with EDC, the HA-EDC bonding structure was degradated slowly whereas the HA-LA bonding structure was degradated quickly and dissappeared completely after 6 days. In case of the membranes crosslinked with BD, all the crosslinked bonding structure degradated slowly. The HA-BD bonding structure maintained its original state about 89, 83% in case of 3, 6 days-degardated samples respectively whereas the HA-LA bonding structure maintained its original state about 83, 65%. The scanning electron microscopy of the degradated membranes showed that the pore density in the surface, and the structure in the surface and cross section, of the before and after-degradation membranes did not change greatly, so the membranes was shown to be applied to materials for tissue engineering.

• KSBB Journal
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• v.21 no.3
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• pp.181-187
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• 2006

In this study, problems related with pH control in electrokinetic(EK) bioremediation of phenanthrene contaminated soil were observed, and the effects of pH control methods on the removal efficiency were investigated to search a further application strategy. In a preliminary experiment, it was found out by flask cultivation that a certain sulfate concentration was needed to degrade phenanthrene well using Sphingomonas sp. 3Y. However, when $MgSO_4$ was used as sulfate source in EK bioremediation, the bacterial activity reduced seriously due to the abrupt decrease of pHs in soil and bioreactor by the combination of magnesium and hydroxyl ions. When another strong buffering compound was used to control the pH problem, the good maintenance of the bacterial activity and pHs could be observed, but the removal efficiency decreased largely. When a low concentration of $MgSO_4$ was added, the removal efficiency decreased somewhat in spite of the good maintenance of neutral pHs. With the addition of NaOH as a neutralizing agent, the removal efficiency also decreased because of the increase of soil pH. Consequently the selection of electrolyte composition was a very important factor in EK bioremediation and some sulfate sources suitable for both bacterial activity and contaminant degradation should be investigated.

• Resources Recycling
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• v.29 no.3
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• pp.61-74
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• 2020

This study was conducted to improve the recycling process of waste fluorescent lamp, and investigate the possibility of using the waste fluorescent lamp glass as a raw material for glass beads, the leaching method of rare earth from the waste phosphor powder, and the possibility of solvent extraction of rare earth from the rare earth leaching solution. The waste phosphor contained 28.9% yttrium oxide, 3.46% cerium oxide, 1.95% europium oxide, 1.76% terbium oxide, and 1.43% lanthanum oxide. As a result of the trial production of glass beads using waste fluorescent lamp glass, it was judged that the production yield and quality were excellent, so that waste fluorescent lamp glass could be used as a raw material for glass beads. The soda roasted waste phosphor was leached in water and thereby the aqueous solution was blown with CO₂ to drop the pH to about 7, Then, Al, Si and residual N₂CO₃ were dissolved, and NaAlCO₃(OH)₂ and SiO₂ were precipitated in the aqueous solution. In the solvent extraction of cyanex272-hydrochloric acid, cyanex272-sulfuric acid, D2EHPA-hydrochloric acid, D2EHPA-sulfuric acid, Ionquest290-hydrochloric acid, Ionquest290-sulfuric acid, p507-hydrochloric acid using xylene as a diluent, the extraction yield of Y, Eu, Ce, La, and Tb are close to 100%. However, in this conditions, the difference in extraction yield for each element, that is, selectivity is 16% or less.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.159-167
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• 2000

In recent years, combined and separated sewer overflows (CSOs, SSOs) have been recognized as a significant pollution problem. To solve this problem a series of experiments were performed in a small scale Rapid Floc Settler (RFS) device to determine its ability in removing micro particles and dissolved materials from polluted waters. The RFS device is a compact physico-chemical wasterwater treatment system. Polyacrylamide (PAM) is used as a coagulant for treating stormwater in the RFS. The results of Jar test showed that PAM could be an excellent coagulant as compared with aluminum sulfate. and ferric chloride. In several experimental conditions, the influence of different variation parameters was tested to measure the efficiency of the RFS. Tests have been carried out with typical CSOs concentrations (50~1.000mg SS/L). The treatment efficiency with regard to SS and COD, which can be obtained at an overflow rate of $130m^3/m^2/day$, are 90% and 80%, respectively. Comparing other sedimentation technologies with RFS, the overflows rate of RFS is ten times faster. The distribution of particle size and number were analyzed. The RFS is suitable for the treatment of CSOs and also the removal of settleable and dissolved materials in urban stormwater runoff.

• Resources Recycling
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• v.25 no.3
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• pp.29-36
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• 2016

The characteristics analysis and pH neutralization test were carried out to use of slurry generated from recycling processes of construction wastes. D (5.0) of raw sludge was $42.4{\mu}m$ and over 60 % of sludge distribute under 45 um (-325 mesh). Muscovite and carbonate minerals were main minerals of fine particles, and the portion of carbonate minerals increased as particle size decreased. Although the more heavy metals were observed in the finer particle size, the contents was found to be less than Korean contaminated soil regulation (area 2). The effects of flocculants addition for accelerating solid-liquid separation were negligible because the slurry already contains excess of coagulant added in the waste concrete recycling process. It was difficult to neutralize the sludge supernatant due to high pH (about 12) by adding acids, but the introduction of $CO_2$ decreased the pH to 8.5, The precipitate recovered during $CO_2$ introduction was determined to be $CaCO_3$ with XRD, and it indicates that high pure $CaCO_3$ could be obtained during the process.

• Applied Biological Chemistry
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• v.22 no.3
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• pp.145-149
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• 1979

The radiochemical purity of $^{14}C(U)-glucose$ solution to be injected to normal laying hen was investigated for studying biokinetics of carbohydrate and lipid metabolism. The liquid scintillation counter was employed for determining the activity of carbon-14. The barium hydroxide and zinc sulfate were adopted to precipitate the protein in the solution. The glucose content in the solution was observed as 0.912 mg per ml, applying Hultman's method. The specific activity of $^{14}C(U)-glucose$ solution was known as 31.3 nCi/mg glucose. The glucose pentaacetate was synthesized to isolate the pure glucose from the solution. The specific activity of pure glucose was measured as 28.5 nCi/mg glucose. Therefore, it was known that the radiochemical purity of the solution was 82.7%.

• Applied Biological Chemistry
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• v.22 no.4
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• pp.191-197
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• 1979

${\beta}-Tyrosinase$ was purified and crystallized from cells of Escherichia intermedia A-21 grown in a medium supplemented with 0.2% L-tyrosine. Molecular weight of its subunit, Km value and absorption spectra were determined. Crystallization methods were also studied to eliminate any unnecessary procedures. The results obtained were as follows: 1. The purification procedure included ammonium sulfate fractionation, dialysis against potassium phosphate buffer, pH 6.0 and pH 7.0, and DEAE-Sephadex column chromatography. In the column chromatography, 11 mg of protein was applied per ml of DEAE-Sephadex for efficiency. 2. Steps of protamine sulfate treatment and Sephadex G-150 gel filtration could be eliminated for this enzyme from the known procedures. 3. The purified enzyme was dissolved in 0.01M potassium phosphate buffer containing 2-mercaptoethanol, with a concentration of 20mg/ml. Crystalline enzyme, which appears as hexagonal rods, was obtained by adding solid fine powdered ammonium sulfate to the enzyme solution. 4. Absorption maxima of the enzyme appeared at 340 and 430nm when associated with pyridoxal phosphate. 5. Km value of the enzyme for L-tyrosine was $2.31{\times}10^{-4}M$ and the molecular weight of its subunit was determined by SDS-polyacrylamide electrophoresis to be approximately 50,000.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.3
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• pp.10-14
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• 1987

우리나라는 이제 그동안의 꾸준한 노력의 결과로 자동차 수출국으로 발돋움하고 있으며 이 분야 에서으 선진국과의 경쟁이 점점 치열해질 전망이다. 이러한 세계 시장에서의 경쟁 대열에서 탈 락되지 않기 위해서는 무엇보다도 제품 품질의 향상, 원가의 절감 등이 이루어져야 할 것이며 이 에 대한 노력을 게을리 해서는 안될 것이다. 한편 이와는 별도로 좀더 다른 각도에서 자동차 공업의 방향을 고찰할 필요가 있다. 즉 미래에도 계속해서 현재의 왕복동 내연기관이 자동차 구동용으로 사용될 것인가 하는 점이다. 엔진의 성능 향상, 연비의 감소, 엄격한 배기가스 규 제에의 대처 등에 대한 연구가 활발히 진행되고 있지만 기술개발에는 한계가 있으며 제품은 점점 복잡하게 되어 결국은 제품가격 및 A/S 비용이 상승되는 역효과를 나타낼 가능성이 높다. 이에 세계적인 자동차 제조회사에서는 오래전부터 새로운 방식의 미래형 자동차 engine 개발에 착수 하였으며 계속적인 연구를 진행하고 있다. 이러한 미래형 자동차 engine의 대표적인 것으로 gas turbine engine이 있다. 가스터어빈이라 하면 우선 항공기용의 jet engine을 생각하게 된다. 그 외에 발전용으로 가스터어빈은 이용되고 있으며 근래 다시 등장한 자동차용의turbocharger 역시 가스터어빈의 한 응용분야라고 할 수 있다. turbocharger의 경우는 내연기관의 출력향상을 주 목적으로 내연기관에 부착되어 이용되고 있는 반면에 gas turbine engine은 기존의 내연기관을 대체하여 자동차 구동용으로 이용되는 점에 그 차이가 있다. 아직은 실용화되징 않았지만 미래형 자동차 기관으로서의 이용가능성이 높은 gas turbine engine을 다음에 간략히 소개하고자 한다. 생산량과 하천수에 의한 생산량과의 비는 풍건물의 경우 0.6, 매물의 경우 0.5였으며 감자의 경우는 0.2이하였다. 4. 염분용수 관개구와 하천수 관개구의 모든작물에서 풍건물 생산량과 축배량 사이에는 강한 직선적인 관계를 보였다. 보리, 감자의 작물 생산량과 축배량사이에도 선형의 관계가 성립되었으나, 밀과 옥수수의 매물 생산량과 축배량사이에는 곡선적인 관계를 나타내었다..18cm)에 필적되는 연평균 4.16cm로 나타났다. 5. 전체 시험구로부터으 연평균 토양유실량은 Sharpsburg 점질양토에 대한 S.C.S 한계허용치 10ton/ha/year 이내로 나타났다. 비처리구에서의 토양유실량은 평균 2.56ton/ha/year로 높게 나타난 반면 3개의 서로 다른 추리구인 비수구, 초생수로구 및 Bromegrass구에서는 각각 0.152, 0.192 및 0.290ton/ha/year로 낮은 결과를 가져왔다. 6. 평균 침전량에 대한 L.S.D. 검정 걸과 전시험구중 비처리구가 고도의 유의차를 나타낸 반면 비수구, 초생수로구 및 Bromegrass 목초구 간에는 아무런 유의차가 인정되지 않았다. 7. 농지보전 처리구인 배수구와 초생수로구는 비처리구에 비해 낮은 침두 유출량과 낮은 토양유실량을 나타내었다.구보다 14% 절감되는 것으로 나타났다.작용하는 것으로 사료된다.된다.정량 분석한 결과이다. 시편의 조성은 33.6 at% U, 66.4 at% O의 결과를 얻었다. 산화물 핵연료의 표면 관찰 및 정량 분석 시험시 시편 표면을 전도성 물질로 증착시키지 않고, Silver Paint 에 시편을 접착하는 방법으로도 만족한 시험 결과를 얻을 수 있었다.째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰