• Clean Technology
• /
• v.7 no.3
• /
• pp.161-167
• /
• 2001

A model was proposed for the removal of poly-dispersed suspended solid by deep bed filtration and the collection efficiency was investigated by computer simulation. Deposited particles on the collector surface may act as additional collector and reduce the pore size of the collector. As a result, the capability of removing suspended particles of the filter bed was improved with the deposition. The filtration process of poly-dispersed suspension shows higher collection efficiency than that of mono-dispersed suspensions. Since the large particles deposited on the collector surface may contribute to the increase of contact between collectors and small particles, the improved overall collection efficiency was obtained.

• Korean Journal of Materials Research
• /
• v.15 no.5
• /
• pp.301-305
• /
• 2005

We fabricated nickel silicide layers on whole non-patterned wafers from $p-Si(100)SiO_2(200nm)$/poly-Si(70 nm)mn(40 nm) structure by 40 sec rapid thermal annealing of $500\~900^{\circ}C$. The sheet resistance, cross-sectional microstructure, surface roughness, and phase analysis were investigated by a four point probe, a field emission scanning electron microscope, a scanning probe microscope, and an X-ray diffractometer, respectively. Sheet resistance was as small as $7\Omega/sq$. even at the elevated temperature of $900^{\circ}C$. The silicide thickness and surface roughness increased as silicidation temperature increased. We confirmed the nickel silicides iron thin nickel/poly-silicon structures would be a mixture of NiSi and $NiSi_2$ even at the $NiSi_2$ stable temperature region.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.7
• /
• pp.901-905
• /
• 2003

The lower critical solution temperature (LCST) of thermosensitive poly(organophosphazenes) with methoxypoly(ethylene glycol) (MPEG) and amino acid esters as side groups was studied as a function of saccharide concentration in aqueous solutions of mono-, di-, and polysaccharides. Most of the saccharides decreased the LCST of the polymers, and the LCST decrease was more prominently observed by saccharides containing a galactose ring, such as D-galactose, D-galactosamine and D-lactose, and also the polysacccharide, 1-6-linked D-dextran effectively decreased the LCST of the polymers. Such an effect was discussed in terms of intramolecular hydrogen bonding of saccharides in polymer aqueous solution. The saccharide effect was found to be almost independent on the kinds of the amino acid esters and MPEG length of the polymers. Such a result implies that the polymer-saccharide interaction in aqueous solution is clearly influenced by the structure of sacchardes rather than by that of the polymers. The acid saccharides such as D-glucuronic and D-lactobionic acid increased the LCST, which seems to be due to their pH effect.

• Journal of the Korean Applied Science and Technology
• /
• v.19 no.2
• /
• pp.131-136
• /
• 2002

As model waterborne acrylic coatings, mono-dispersed poly(butyl acrylate-methyl methacrylate) copolymer latexes of random copolymer and core/shell type graft copolymer were prepared by seeded multi-staged emulsion polymerization with particle size of $180{\sim}200$ nm using semi-batch type process. Sodium lauryl sulfate and potassium persulfate were used as an emulsifier and an initiator, respectively. The effect of particle texture including core/shell phase ratio, glass transition temperature and crosslinking density, and film forming temperature on the film formation and final properties of film was investigated using SEM, AFM, and UV in this study. The film formation behavior of model latex was traced simultaneously by the weight loss measurement and by the change of tensile properties and UV transmittance during the entire course of film formation. It was found that the increased glass transition temperature and higher crosslinking degree of latex resulted in the delay of the onset of coalescence of particles by interdiffusion during film forming process. This can be explained qualitatively in terms of diffusion rate of polymer chains. However, the change of weight loss during film formation was insensitive to discern each film forming stages-I, II and III.

• Journal of Periodontal and Implant Science
• /
• v.41 no.2
• /
• pp.54-59
• /
• 2011

Purpose: The aim of this study was to define the immunoreactive specificity of Porphyromonas gingivalis (P. gingivalis) heat shock protein (HSP) 60 in periodontitis and atherosclerosis. Methods: In an attempt to define the cross-reactive bacterial heat-shock protein with human self-antigen at molecular level, we have introduced a novel strategy for cloning hybridoma producing anti-P. gingivalis HSP 60 which is polyreactive to bacterial HSPs or to the human homolog. Results: Five cross-reactive clones were obtained which recognized the #19 peptide (TLVVNRLRGSLKICAVKAPG) among 37 synthetic peptides (20-mer, 5 amino acids overlapping) spanning the whole molecule of P. gingivalis HSP 60. We have also established three anti-P. gingivalis HSP 60 monoclonal antibodies demonstrating mono-specificity. These clones recognized the #29 peptide (TVPGGGTTYIRAIAALEGLK). Conclusions: Peptide #19 and #29 of P. gingivalis HSP 60 might be important immunoreactive epitopes in the immuno-pathogenic mechanism of bacterial antigen-triggered autoimmune diseases.

• Macromolecular Research
• /
• v.12 no.6
• /
• pp.581-585
• /
• 2004

A copolymer P[OSA-MI] was synthesized by copolymerization of its corresponding monomers, N-phenyl maleimide (MI) and 2-octen-l-ylsuccinic anhydride (OSA). The polymer (poly[2-[1-(2,5-dioxo-l-phenylpyrroli­din-3-ylmethyl)heptyl]-succinic acid 4-(2-$\{$ethyl-[4-(4-nitrophen-ylazo)phenyl]amino$\}$ethyl)ester]) P[DR1MA-MI] was obtained from the reaction of P[OSA-MI] with 2-[4-(4-nitrophenylazo)-N-ethylphenylamino] ethanol (DR1). A stable monolayer of P[DRIMA-MI] was formed by spreading the solution of the polymer in chloroform. In Y-type Langmuir-Blodgett (LB) films prepared using this Langmuir-Blodgett method, the second harmonic waves generated from adjacent mono layers canceled each other out. In X-and Z-type LB films, the second harmonic intensity increased upon increasing the number of monolayers, but this increase was somewhat smaller than predicted by the square law. This phenomenon is due to defects or imperfect alignment of the dipoles in the LB film. The generation of second harmonic waves from Y-type LB films having an even number of mono layers supports this argument. The degree of imperfection seemed to increase as the number of layers increased. The second-order nonlinear optical properties of spin-cast films of these polymers were also measured. The largest second harmonic coefficient of the poled P[DRIMA-MI] film coated on a glass plate was 19 pm/V.

• Applied Chemistry for Engineering
• /
• v.16 no.2
• /
• pp.212-216
• /
• 2005

Benzotriazole which is used as a corrosion inhibitor for the zinc coated steel was intercalated into Na-MMT. X-ray diffraction experiments on intercalant/silicate composite samples demonstrated that the intercalation of intercalant leads to an increase in the spacing between silicate layers. Water soluble poly(ethylene-co-acrylic acid) (PEA) nanocomposites, to use as a coating agent, were prepared with these modified MMT. We found that mono-layered silicates were dispersed in PEA matrix and those resultants were exfoliated nanocomposites. From the result of salt spray test, we found that this coating agent prepared with water soluble poly(ethylene-co-acrylic acid) (PEA) nanocomposite provided good corrosion protection. These results were caused by decreasing the rate of oxygen permeation from silicate layers dispersed homogeneously in PEA matrix and the effect of corrosion inhibitor from benzotriazole.

• Polymer(Korea)
• /
• v.30 no.4
• /
• pp.298-304
• /
• 2006

Blends of poly (acrylic acid-co-maleic acid)(PAM) with poly (vinyl alcohol)(PVA) were obtained by solution blending. The blends were solvent-on to a film to examine thermo-mechanical properties and gas permeability. The transition temperatures $(T_g\;and\;T_m)$ of the blends remained constant regardless of PAM contents. However, the values of enthalpy changes corresponding to melting transition $({\Delta}H_m)$ and initial degradation temperature $({T_D}^i)$ were decreased with increasing PAM content. The values of ultimate strength and initial modulus gave the maximum value at the 12 wt% PAM then decreased with further increase of PAM content up to 15 wt%. To measure the gas permeability of the PVA/PAM blend films, the PVA blend solutions were coated onto both biaxially oriented propylene (BOPP) and poly (ethylene terephthalate)(PET) films. The oxygen transmission rate $(O_2\;TR)$ permeability values mono- tonically decreased with increasing PAM content. However, moisture vapor transmission rate was not affected by PAM content.

• Animal cells and systems
• /
• v.1 no.2
• /
• pp.323-328
• /
• 1997

We have previously shown that chick muscle extracts contained at least 10 different ubiquitin C-terminal hydrolases (UCHs). In the present studies, one of the enzymes, called UCH-9, was purified by conventional chromatographic procedures using $^{125}l$-labeled ubiquitin-${\alpha}$NH-MHISPPEPESEEEEE HYC (Ub-PESTc) as a substrate. The purified enzyme behaved as a 27-kDa protein under both denaturing and nondenaturing conditions, suggesting that it consists of a single polypeptide chain. It was maximally active at pHs between 7 and 8.5, but showed little or no activity at pH below 6 and above 10. Lice other UCHs, its activity was strongly inhibited by sulfhydryl blocking reagents, such as iodoacetamide, and by Ub-aldehyde. In addition to Ub-PESTc, UCH-9 hydrolyzed Ub-aNH-protein extensions, including Ub-${\alpha}NH$-carboxyl extension protein of 80 amino acids and Ubo-${\alpha}NH$-dihydrofolate reductase. However, this enzyme was not capable of generating free Ub from mono-Ub-${\varepsilon}NH$-protein conjugates and from branched poly-Ub chains that are ligated to proteins through ${\varepsilon}NH$-isopeptide bonds. This enzyme neither could hydrolyze poly-His-tagged di-Ub. These results suggest that UCH-9 may play an important role in production of free Ub and ribosomal proteins from their conjugates.

• Journal of Plant Biotechnology
• /
• v.1 no.2
• /
• pp.69-77
• /
• 1999

Safflower is an important medicinal plant that has been used in China, Korea and Japan for thousands of years. The red and yellow pigments obtained from the petals of safflower can invigorate blood, release stagnation and promote menstruation. In addition, these pigments are used safely in processed foods and soft drinks as naturally harmless rotor additives. On the other hand, the seed of safflower contains 30-40% oil with higher level of mono- and poly-unsaturated fatfy acid profiles and elevated levels of $\alpha$-tocopherol. In this paper, we describe advances in the production of pigments and $\alpha$-tocopherol by cell culture in safflower.