• 한국동물학회지
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• 제17권2호
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• pp.93-102
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• 1974

토끼의 골격근 小胞體 切片을 遠心分離하여 그 ATPase 活性의 生化學的性質을 $Mg^++ - ATPase 와 (Mg^++ - Ca^++)$-ATPase로 구분하여 조사하였다. $(Mg^++ - Ca^++)$-ATPase의 活性은 $0^\\circ - 40^\\circ C$의 범위, 그리고 pH 6.4-7.6의 범위에서는 $Mg^++$-ATPase보다 훨씬 높다. 이 현상은 온도가 높을수록 더욱 현저하다. 活性化에너지는 온도 $0^\\circ -40^\\circ C$의 범위에서는 $Mg^++$-ATPase가 14kcal/mole, $(Mg^++ - Ca^++)$-ATpase 가 21kcal/mole, 그리고 total ATPase 가 18kcal/mole 이다. 이 活性化에너지의 값은 pH와 Mg 濃度에 무관하다. 이들 효소의 Km의 값은 $Mg^++$-ATPase 가 0.36mM , $(Mg^++ - Ca^++)$-ATpase가 2.20mM, 그리고 total ATPaserk 0.86 mM이다.

• 한국균학회지
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• 제14권1호
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• pp.79-84
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• 1986

Ganoderma lucidum의 개체배양물(個體培養物)로 부터 얻은 cellulase를 ammonium sulfate fractionation으로 조정제(組精製)한 후(後) 이 효소(酵素)의 기본적(基本的)인 특성(特性)을 조사(調査)하였다. 이 효소(酵素)의 최적작용(最摘作用) pH와 온도(溫度)는 각각 pH $4.0{\sim}7.0$사이와 $50^{\circ}C$ 이하(以下)의 온도(溫度)에서는 비교적(比較的) 안정(安定)하였다. CMC-2Na분해(分解)에 대한 activation energy는 6.2 Kcal/mole이었다. $Mg^{++},\;Co^{++}$에 의해서 효소활성(酵素活性)이 증가(增加)되었으나 $Hg^{++}$에 의해서는 저해(沮害)되었다. 한편 본(本) 효소활성(酵素活性)은 SDS에 의해서 약 27%저해(沮害)된 것을 제외(除外)하고는 여러가지 chemical reagents에 의해서는 아무런 영향(影響)을 받지 않았다. 본(本) 효소(酵素)의 CMC-2Na에 대한 Km치(値)는 2.4 mg/ml였으며 CMC-2Na 이외(以外)에 천연(天然) cellulose에도 작용(作用)을 하였다.

• Molecules and Cells
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• 제26권5호
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• pp.462-467
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• 2008

TPA is known to cooperate with an activated Ras oncogene in the transformation of rodent fibroblasts, but the biochemical mechanisms responsible for this effect have not been established. In the present study we used c-fos promoter-luciferase constructs as reporters, in transient transfection assays, in NIH3T3 cells to assess the mechanism of this cooperation. We found a marked synergistic interaction between TPA and a transfected v-Ha-ras oncogene in the activation of c-fos promoter and SRE. SRE has binding sites for TCF and SRF. A dominant-negative Ras (ras-N17) inhibited the TPA-Ras synergy by blocking the PKC-MAPK-TCF pathway. Dominant-negative RhoA and Rac1 (but not Cdc42Hs) inhibited the TPA-Ras synergy by blocking the Ras-Rho-SRF signaling pathway. Constitutively active $PKC{\alpha}$ and $PKC{\varepsilon}$ showed synergy with v-Ras. These results suggest that the activation of two distinct pathways such as Ras-Raf-ERK-TCF pathway and Rho-SRF pathway are responsible for the induction of c-fos by TPA and Ras in mitogenic signaling pathways.

• Environmental Engineering Research
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• 제22권4호
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• pp.384-392
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• 2017

Mango shell (MS) and mango shell activated carbon (MSAC) was used to adsorb crude oil from water at various experimental conditions. The MSAC was prepared by carbonization at $450^{\circ}C$ and chemical activation using strong $H_3PO_4$ acid. The adsorbents were characterized with Fourier Transform Infrared spectroscopy. Investigations carried out included the effects of parametric variations of different adsorbate dose, adsorbent dose, time, temperature, pH and mixing speed on the adsorption of crude oil. The equilibrium isotherm for the adsorption process was determined using Langmuir, Freundlich, Temkin and Dubinin Radushkevich isotherm models. Temkin isotherm was found to fit the equilibrium data reasonably well than others. The result demonstrated that MSAC was more effective for crude oil adsorption than raw mango shell. Optimum conditions were also presented. The enhanced effect from activation was justified statistically using Analysis of Variance and Bonferroni-Holm Posthoc significance test. The pseudo first order kinetics gave a better fit for crude oil adsorption with both MS and MSAC.

• 한국세라믹학회지
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• 제26권4호
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• pp.471-478
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• 1989

In this study we investigated the gelation time of sol which containing mixtures of TEOS with H2O, ethanol, HCl in the preparation of monolithic silica glass through Sol-Gel method. In this case apparent activation energies were observed by Arrhenius equation. We investigated the conversion from gel to glass in drying and heat treatment stages using DT-TG, FT-IR, XRD analysis and dried gel conversed to glass by heat treatment up to 85$0^{\circ}C$. The results of this experiment showed that the gelation time of solutions were promoted when increasing the amount of addition of H2O and HCl catalyst for TEOS and high reaction temperature of solution.

• Environmental Engineering Research
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• 제23권3호
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• pp.339-344
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• 2018

The Cu loading of a cubic $Ce_{0.8}Zr_{0.2}O_2$-supported Cu catalyst was optimized for a single-stage water gas shift (WGS) reaction. The catalyst was prepared by a co-precipitation method, and the WGS reaction was performed at a gas hourly space velocity of $150,494h^{-1}$. The results revealed that an 80 wt% $Cu-Ce_{0.8}Zr_{0.2}O_2$ catalyst exhibits excellent catalytic performance and 100% $CO_2$ selectivity ($X_{CO}=27%$ at $240^{\circ}C$ for 100 h). The high activity of 80 wt% $Cu-Ce_{0.8}Zr_{0.2}O_2$ catalyst is attributed to the presence of abundant surface Cu atoms and the low activation energy of the resultant process.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.108-108
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• 2015

In order to investigate on hydroxyapatite precipitation phenomena on nanotubular Ti-29Nb-xHf ternary alloys, Ti-29Nb-xHf alloys contained (0% to 15%) Hf were manufactured using arc melting furnace. Formation of nanotubular structure was achieved by an electrochemical method in 1M $H_3PO_4$ electrolytes containing 0.8%wt. % NaF. Electrochemical deposition was carried out using cyclic and voltammetry(CV) method at $85^{\circ}C$ in $5mM\;Ca(NO_3)_2+3mM\;NH_4H_2PO_4$. HA coating on nanotube formed Ti-29Nb-xHf ternary alloys showed a good wettability.

• Bulletin of the Korean Chemical Society
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• 제16권2호
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• pp.157-163
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• 1995

The adsorption and decomposition of NO on a stepped Pt(111) surface have been studied using thermal desorption spectroscopy and Auger electron spectroscopy. NO adsorbs molecularly in two different states of the terrace and the step, which are distinguishable in thermal desorption spectra. NO dissociates via a bent species at the step sites on the basis of vibrational spectrum data reported previously. The dissociation of NO is an activation process : the activation energy is estimated to be about 2 kcal/mol. Increase in the NO dissociation with adsorption temperature is explained by a process controlled by diffusion of the dissociated atomic nitrogen from the step to the terrace of the surface. In addition to NO and N2, the desorption peak of N2O is observed. We conclude that the formation of N2O is attributed to surface reaction of NO and N adsorbed on the surface.

• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 춘계총회 및 학술대회
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• pp.144.1-144.1
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• 2000

• Archives of Pharmacal Research
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• 제12권2호
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• pp.88-93
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• 1989

In order to obtain some informations about the effect of molecular weight on the release rate of drug from drug carrier, two types of poly-L-glutamic acid (PLGA)-cytarabine (ara-C) conjugates, PLGA-ara-C:I and PLGA-ara-C:II, were synthesized using two types of PLGA having different average molecular weight, 43,000 and 77,800, respectively. The PLGA-ara-C conjugates were synthesized by mixed anhydride method and found to be covalently linked. Both types of conjugates charged negatively at biological pH. The pH-dependent release rate of ara-C was observed in both cases, and the release rate was accelerated in basic, acidic conditions (the k values were 0.015 $day^{-1}$ at pH 7.0, 0.024 $day^{-1}$ at pH 5.0, and 0.059 $day^{-1}$ at pH 9.0 in the case of PLGA-ara-C:I) and in the presence of pretense. The time required for the release of 16.5% of ara-C from PLGA-ara-C:I were 8 hr and 144 hr in the presence and absence of protease, respectively. Although both types of conjugates showed similar drug substitution ratio, they showed different release rates. Between the two types of conjugates, PLGA-ara-C:II showed the faster release rate (0.030 vs 0.042 $day^{-1}$ in pH 7.4 phosphate buffer solution at $37^{\circ}C$) and the smaller activation energy for the release of drug (12.5 vs 7.7 Kcal/mol) than PLGA-ara-C:I. The characteristic effect of molecular weight on the release rates of PLGA-ara-C conjugates suggests that the drug release rate might be effectively controlled over a prolonged period of time by the combined use of the different types of PLGA-ara-C conjugates having different molecular weights.