한외여과된 돈혈청으로부터 DEAE - Sephacel Chromatography 에 의한 면역단백질의 분리

박우문,유익종,전기홍,이무하 한국축산학회 1997 한국축산학회지 Vol.39 No.1

Concentrated porcine serum with ultrafiltration 30KDa was purified with DEAF-Sephacel column chromatography. Buffer solution with pH 7 to 9 and buffer concentration with 0.01M to 0.05M, and NaCl gradient with 0M∼0.5M, 0M∼0.8M and 0M∼1.0M were used respectively for chromatographic purification. Optimal conditions were at pH 8.0, buffer conc. 0.03M and salt conc, 0M∼0.5M with immunoprotein concentration 82% and production yield 43%. Purified immunoprotein was identified in the molecular weight 50KDa and 15KDa by electrophoresis.

Interconversion between cyclodimer and cyclotrimer: Synthesis and characterization of cyclo-[Pd(II)Cl₂(N-N)] complexes

Kang, H.J.,Noh, T.H.,Na, Y.M.,Yoo, K.H.,Jung, O.S. Elsevier Sequoia [etc.] 2009 Inorganica chimica acta Vol.362 No.6

The reaction of (COD)PdCl<SUB>2</SUB> (COD=1,5-cyclooctadiene) with (3-Py)<SUB>2</SUB>SiR<SUB>1</SUB>R<SUB>2</SUB> (3-Py=3-pyridyl; R<SUB>1</SUB>=Ph, R<SUB>2</SUB>=Ph (m-pdps); R<SUB>1</SUB>=Ph, R<SUB>2</SUB>=Me (m-pmps)) in acetone affords single crystals consisting of cyclodimers, [PdCl<SUB>2</SUB>((3-Py)<SUB>2</SUB>SiR<SUB>1</SUB>R<SUB>2</SUB>)]<SUB>2</SUB>, whereas the same reaction in a mixture of dichloromethane and ethanol yields amorphous spheres consisting of cyclotrimers, [PdCl<SUB>2</SUB>((3-Py)<SUB>2</SUB>SiR<SUB>1</SUB>R<SUB>2</SUB>)]<SUB>3</SUB>. In a boiling chloroform solution, the cyclodimers are completely converted to cyclotrimers. These cyclotrimers, in the 10-60<SUP>o</SUP>C range, are partly returned to cyclodimers. By contrast, the reaction of (COD)PdCl<SUB>2</SUB> with (3-Py)<SUB>2</SUB>SiR<SUB>1</SUB>R<SUB>2</SUB> (R<SUB>1</SUB>=Bu, R<SUB>2</SUB>=Me (m-pbms); R<SUB>1</SUB>=dodecyl, R<SUB>2</SUB>=Me (m-pddms)) yields amorphous spheres consisting of cyclotrimers irrespective of solvents. Both [PdCl<SUB>2</SUB>(m-pbms)]<SUB>3</SUB> and [PdCl<SUB>2</SUB>(m-pddms)]<SUB>3</SUB> are initially cyclotrimers in chloroform, but they exist as a mixture of cyclodimers and cyclotrimers in solution in the 10-60<SUP>o</SUP>C range. The metallacycles tend to form cyclodimers in the order m-pdps>m-pmps>m-pbms>m-pddms. The equilibrium between cyclodimers and the cyclotrimers is sensitive to solvent, temperature, and concentration as well as molecular structure.

RAPD PCR와 ITS-RFLP 분석에 의한 국내 피부진균속 분류 및 동정

이영선,유재일,최연화,주형렬,박만석,김봉수 국립보건연구원 1998 국립보건원보 Vol.35 No.-

Effects of catalpalactone on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells

Huang, H.S.,Han, X.H.,Hwang, B.Y.,Park, J.I.,Yoo, S.K.,Lee, H.J.,Lim, S.C.,Lee, M.K. Elsevier Science B.V 2008 Environmental toxicology and pharmacology Vol.26 No.1

The effects of catalpalactone on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells were investigated. Catalpalactone at 5-30μM decreased intracellular dopamine content with the IC<SUB>50</SUB> value of 22.1μM. Catalpalactone at 5-20μM, but not 30μM, did not alter cell viability. Catalpalactone at 20μM inhibited tyrosine hydroxylase (TH) and aromatic-l-amino acid decarboxylase (AADC) activities. Catalpalactone also decreased cyclic AMP levels and inhibited TH phosphorylation. In addition, catalpalactone at 20μM reduced the increases in dopamine levels induced by L-DOPA (20-50μM). Catalpalactone (5-30μM) associated with L-DOPA (50-100μM) enhanced L-DOPA-induced cytotoxicity at 48h, which was prevented by N-acetyl-l-cysteine. These results suggest that catalpalactone inhibited dopamine biosynthesis by reducing TH and AADC activities and enhanced L-DOPA-induced cytotoxiciy in PC12 cells.

Features and Properties of $YBa_2$$Cu_3$$O_{7-x}$ Films Grown on SrTi$O_3$ by High Frequency PLD

Shi, D.Q.,Ko, R.K.,Song, K.J.,Chung, J.K.,Choi, S.J.,Park, Y.M.,Shin, K.C.,Yoo, S.I.,Park, C. The Korean Superconductivity Society 2003 Progress in superconductivity Vol.5 No.1

YBCO films were deposited with various thicknesses from 100nm to 1.6$\mu\textrm{m}$ on single crystal $SrTiO_3$ substrates by pulsed laser deposition (PLD). The effects of different deposition conditions, especially different deposition rates by means of changing the pulsed laser frequency up to 200Hz, on the J$_{c}$ value were studied. For YBCO film with the thickness of 200nm, the $J_{c}$ value of $2.1MA/\textrm{cm}^2$ has been achieved under the high deposition rate of 3.2nm/s (190nm/min). The $J_{c}$ can be maintained greater than $1M/\textrm{cm}^2$ with the thickness less than 1$\mu\textrm{m}$. The X-ray analysis was used to examine the texture, crystallization and surface quality. The SEM was employed to analyze the surface of YBCO, and it was shown the surface of YBCO film became rougher with increasing the thickness. There were many large singular outgrowths and networks of outgrowths on the surface of YBCO films which lowered the density of thick YBCO film. The outgrowth network was probably the a-axis YBCO corresponding to XRD $\theta$-2$\theta$scan and $\chi$-scan which were used to characterize a-axis orientation of YBCO film. The reason for J$_{c}$ declining with increasing the thickness was studied and discussed.sed.

Self-templated synthesis of hollow silica microspheres using Na2SiO3 precursor

Yoo, B. U.,Han, M. H.,Nersisyan, H. H.,Yoon, J. H.,Lee, K. J.,Lee, J. H. Elsevier Science B.V., Amsterdam. 2014 Microporous and mesoporous materials Vol.190 No.-

A facile synthesis method has been developed to directly convert solid Na2SiO3 hollow microspheres into non-aggregated hollow SiO2 microspheres at ambient pressure and temperature. An initial dispersion of Na2SiO3 microspheres (mean diameter: 10-50 mu m) in ethanol was prepared, and subsequent hydrolysis of Na2SiO3 was performed using a HCl solution. Other precipitants such as ammonium salts (NH4Cl, (NH4)(2)SO4) and boron oxide (B2O3) were also tested. The characteristics of the synthesized hollow microspheres were investigated in detail by thermogravimetric analysis, field emission scanning electron microscopy, N-2 adsorption-desorption isotherms, and X-ray diffraction. The as-prepared SiO2 microspheres were hollow with diameters between 10 and 50 mu m. The surface area of these microspheres, determined by Brunauer-Emmett-Teller analysis, was in the range 193-288 m(2) g(-1). Using the proposed method, the size and shape of the obtained silica microspheres are largely determined by the size of low-cost and environmentally friendly precursor sodium silicate microspheres. (C) 2014 Elsevier Inc. All rights reserved.

Injection molding of a nanostructured plate and measurement of its surface properties

Yoo, Y.E.,Kim, T.H.,Choi, D.S.,Hyun, S.M.,Lee, H.J.,Lee, K.H.,Kim, S.K.,Kim, B.H.,Seo, Y.H.,Lee, H.G.,Lee, J.S. Elsevier 2009 CURRENT APPLIED PHYSICS Vol.9 No.2

This paper highlights recent research on the injection molding of a surface nanostructured substrate with super-hydrophobicity or dry adhesiveness. An anodic aluminum oxidation (AAO) membrane or layer on an Si wafer is used as a molding master for surface nanostructures. The AAO membrane or layer has closely packed nanoholes; depending on the AAO membrane used, the nanoholes have a diameter of around 200nm and a depth that varies from a few hundred nanometers to 60μm. This AAO master is installed directly in the injection molding tool, or the AAO holes are replicated on the nickel stamper by an electroforming process and installed in the injection molding tool. Either a high temperature (>T<SUB>g</SUB> of the molding material) mold or a rapid heating (up to 200<SUP>o</SUP>C) and cooling (<70<SUP>o</SUP>C) mold is used to fill the high aspect ratio nanoholes with thermoplastic melt for the injection molding. These high aspect ratio nanoholes are extremely difficult to fill with melt in a conventional injection molding process. This paper proposes a new simple and efficient rapid heating and cooling method that heats the stamper by means of the electrical resistance of the stamper itself. Depending on the aspect ratio of the structures and the type of master, a chemical etching or mechanical ejecting process is used to release the molded surface nanostructures. With the use of an AAO membrane and a high temperature mold, some polypropylene disks with a nanohairy surface and some polycarbonate plates with a nanopillar on the surface are injection molded at several different mold temperatures for the purpose of studying the replication of the surface nanostructures. In addition, the contact angle of the water and the adhesion force on the molded surfaces are measured to investigate the effect of the surface nanostructures on the hydrophobicity or dry adhesiveness.

High-J_c GdBa₂Cu₃O_7-δ films fabricated by the metal-organic deposition process

Lee, J.W.,Shin, G.M.,Moon, S.H.,Yoo, S.I. North-Holland 2010 Physica. C, Superconductivity Vol.470 No.20

We report a successful fabrication of high-J<SUB>c</SUB> GdBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7-δ</SUB> (GdBCO) films by the metal-organic deposition process on the LaAlO<SUB>3</SUB> (LAO) (001) substrates. The coating solution was prepared by mixing Gd, Cu fluorine-free sources with Ba trifluoroacetate. Samples were dip-coated, pyrolized within 3h at the temperature up to 400<SUP>o</SUP>C in a humid oxygen atmosphere, and finally fired at various high temperatures in 100ppm Ar/O<SUB>2</SUB> atmosphere. The GdBCO films fired at 775 and 800<SUP>o</SUP>C exhibited J<SUB>c</SUB> values of ~2.1MA/cm<SUP>2</SUP> at 77K in a self-field, which are attributable to both high T<SUB>c,zero</SUB> values of ~89K and high in-plane textures of 1.3-1.4<SUP>o</SUP>. Above 800<SUP>o</SUP>C, however, the superconducting properties of GdBCO films are degraded due to the thermal decomposition of GdBCO film in 100ppm Ar/O<SUB>2</SUB> atmosphere.

Effect of Si interlayer thickness and post-metallization annealing on Ge MOS capacitor on Ge-on-Si substrate

Yoo, O.S.,Oh, J.,Kang, C.Y.,Lee, B.H.,Han, I.S.,Choi, W.H.,Kwon, H.M.,Na, M.K.,Majhi, P.,Tseng, H.H.,Jammy, R.,Wang, J.S.,Lee, H.D. Elsevier Sequoia 2008 Materials science & engineering. B, Advanced funct Vol.154 No.-

We demonstrated the effect of post-metallization annealing and Si interlayer thickness on Ge MOS capacitor on Ge-on-Si substrate with HfO<SUB>2</SUB>/TaN. Ge outdiffusion and oxygen interdiffusion were completely suppressed by thick Si interfacial layer. As a result, formation of insufficient low-k Ge oxides was effectively inhibited. It is confirmed that gate current of Si passivated Ge MOS was decreased by Si IL and decrease of gate current, J<SUB>g</SUB> is saturated after Si IL of 2nm. It was also observed that when Si IL is thick enough to restrict Ge outdiffusion, increase of J<SUB>g</SUB> is not due to the temperature-induced Ge outdiffusion but due to the partial crystallization of HfO<SUB>2</SUB> at higher annealing temperature.

LiF - BeF2 용융염상에서 금속과 금속 산화물의 불화 용해반응

유재형,황두성,정원명,우문식,이규일,박진호,박소진 한국공업화학회 1999 응용화학 Vol.3 No.1

A conversion technology of long-lived radioactive nuclides is to separate the elements involved in spent fuel and convert them into physical and chemical type suited to fuel for transmutation. This study has been investigated the experiments tar fluorination-dissolution of Zr , UO₂, and CeO₂. These compounds are components involved in spent fuel and especially, Zr is the cladding material of fuel. The fraction of fluorination-dissolution was increased linearly with time. Zr and UO₂ were converted respectively 24.2,5.2% after 3hours. CeO₂ was converted into fluoride only 0,19%. This is considered to be due to the solubility of H₂ in the LiF-BeF₂ molten salt. Because hydrogen is used to reduce CeO₂ to CeF₃ but the solubility of H₂ is very low in the molten salt.