• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.353-353
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• 2008

Carbon nanotubes (CNTs) are attractive for field emitter because of their outstanding electrical, mechanical, and chemical properties. Several applications using CNTs as field emitters have been demonstrated such as field emission display (FED), backlight unit (BLU), and X-ray source. In this study, we fabricated a CNT cathode using transparent ultra-thin CNT film. First, CNT aqueous solution was prepared by ultrasonically dispersing purified single-walled carbon nanotubes (SWCNTs) in deionized water with sodium dodecyl sulfate (SDS). To obtain the CNT film, the CNT solution in a milliliter or even several tens of micro-litters was deposited onto a porous alumina membrane through vacuum filtration process. Thereafter, the alumina membrane was solvated by the 3 M NaOH solution and the floating CNT film was easily transferred to an indium-tin-oxide (ITO) glass substrate of $0.5\times0.5cm^2$ with a film mask. The transmittance of as-prepared ultra-thin CNT films measured by UV-Vis spectrophotometer was 68~97%, depending on the amount of CNTs dispersed in an aqueous solution. Roller activation, which is a essential process to improve the field emission characteristics of CNT films, increased the UV-Vis transmittance up to 93~98%. This study presents SEM morphology of CNT emitters and their field emission properties according to the concentration of CNTs in an aqueous solutions. Since the ultra-thin CNT emitters prepared from the solutions show a high peak current density of field emission comparable to that of the paste-base CNT emitters and do not contain outgassing sources such as organic binders, they are considered to be very promising for small-size-but-high-end applications including X-ray sources and microwave power amplifiers.

• Microbiology and Biotechnology Letters
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• v.10 no.4
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• pp.289-295
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• 1982

Streptomyces bobili (YS-40) isolated from soil was tested that it had drug resistance against penicillin, cephalosporin series antibiotics and other antibiotics in the previous paper. The treatment of Streptomyces bobili, (YS-40) with ethidium bromide (EtBr), acriflavine and sodium dodecyl sulfate. (SDS) resulted in the elimination of R-plasmid from the host strain. Minimum growth inhibitory concentrations (MIC) of Hg, Ag, penicillin-G, ampicillin, chloramphenicol, oxytetracycline, streptomycin and kanamycin were found to be 15, 10, > 3, 000, > 100, > 1, 000, > 100, < 5 and < 5$\mu\textrm{g}$/$m\ell$ respectively. Among the curing agents, EtBr was proved to be the most powerful compound for the elimination of R-plasmid in the strain and the elimination rate with EtBr(10$\mu\textrm{g}$/$m\ell$) was about 98%. Optimal pH to. the elimination of R-plasmid was pH 7.0 and the R-plasmid in the cells incubated for 24 hrs was proved to be eliminated most effectively. Aerial mass color, soluble pigment formation and reverse side color were reported to be often the plasmid associated characteristics of the R-plasmid bearing bacteria. But these characteristics of the uncured and cured Streptomyces bobili, (YS-40) showed no changes in the most of the pigment formation media tested in this work.

• Biomolecules & Therapeutics
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• v.9 no.1
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• pp.7-14
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• 2001

The chicken meat has been reported as one of the food causing allergic reactions predominantly to Korean. At present, several in vitro tests for immunoglobulinG (IgG)-mediated as well as IgE-mediated food allergy are available. 13 clinically chicken meat-allergic patients were investigated together with 4control subjects for identification of chicken meat-specific reactivity by ELISA. Also, protein profile and IgE, IgGtotal and IgG4-reacting allergens were detected by means of sodium dodecyl sulfate-polyacrylamide gel electro-phoresis (SDS-PAGE)and immunoblotting. Chicken meat extracts were prepared as raw, heated, heat and simulated gastric fluid (SGF) treated samples to characterize the stability of allergen to physicochemical treatment. SDS-PAGE revealed 9~200 kDa bands. And in immunoblotting 7 sera were identified most major bands between 10 and 78 kDa. In case of IgE, six proteins (17, 26, 35, 40, 78 kDa) were predominant in heat-treated extract, and the one (35 kDa) was present in SGF-treated preparations. In case of IgG$_{total}$ and IgG4, most of them showed a patters simmilar to IgE. There were significant differences (P<0.05) in IgE, IgG$_{total}$ , IgG4 Abs to chicken meat between the allergic and control subjects in ELISA. In addition, the concentration of IgG4Abs in the challenge-positive subjects was significantly higher than that of control subjects. It is considered that the specific IgE response to chicken meat was rarely prevalent to Koreans. However, the specific IgG4 response play an important role in the development of allergic symptoms.

• The Korean Journal of Mycology
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• v.33 no.2
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• pp.75-80
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• 2005

A carboxymethyl cellulase (CMCase) has been purified from Loweporus roseoalbus. The molecular weight of the purified CMCase was estimated to be 28.5 kDa by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The maximum activity of the purified CMCase was observed at pH 4.0 and $30^{\circ}C$, and stable for pH 3 to 5 to maintain 60% activity. The CMCase activity was activated by SDS and inhibited by PMSF and 1,10-phenanthroline. The enzyme activity was also decreased by the addition of ethylene diamine tetraacetic acid (EDTA), suggesting that the purified CMCase is metalloenzyme.

• Journal of the Korean GEO-environmental Society
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• v.12 no.10
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• pp.23-28
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• 2011

This study was conducted to investigate the adsorption characteristics of various surfactants including biosurfactant, SWA 1503, Triton X-100 and sodium dodecyl sulfate(SDS) on soil. The Freundlich adsorption isotherm equation was found to be the best to describe experimental results. The amount of adsorbed surfactant on soil increased as the content of clay increased. The results showed that surfactant was adsorbed mainly on the surface and the pores of soil since the surface area of clay was larger than that of sand. The amount of adsorbed surfactants on soil was as follows: Biosurfactant > SWA 1503 > Triton X-100 > SDS.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.413-419
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• 1998

Aryl acylamidase [EC 3.5.1.13] present in an acetaminophen-assimilating Pseudomonas sp. has been purified to a homogeneity using series of ammonium sulfate fractionation, DEAE-Sephacel anion exchange, Phenyl-Sepharose CL-4B hydrophobic, and Sephadex G-100 gel-permeation chromatography. The molecular weight, which was estimated by gel-permeation filtration and sodium dodecyl sulfate polyacylamide gel electrophoresis, was about 57 kDa and 56 kDa, respectively, indicating that this enzyme is a monomeric protein. The optimum pH was 10.5 and the optimum temperature was 40$^{\circ}C$. After incubation of the enzyme at 50$^{\circ}C$ for 30 min, residual activity of the enzyme was 34% compared to its original activity. The Km values for acetaminophen and 4'-nitroactanilide were 0.10 mM and 0.11 mM, respectively.

• Archives of Pharmacal Research
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• v.28 no.5
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• pp.561-565
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• 2005

Bacterial arylsulfate sulfotransferase (ASST) catalyzes the transfer of sulfate group from a phenyl sulfate ester to a phenolic acceptor. The promoter region and the transcripti on start sites of Enterobacter amnigenus astA have been determined by primer extension analysis. Northern blot analysis resolved two mRNA species with lengths of 3.3 and 2.0 kb, which correspond to the distances between the transcriptional initiation sites and the two inverted repeat sequences (IRSs). By length, the 3.3 kb RNA could comprise the three-gene (astA with dsbA and dsbB) operon. ASST has three highly conserved cysteine residues. Reducing and non-reducing SDS-PAGE and activity staining showed that disulfide bond is needed for the activity of the enzyme. To identify the cysteine residues responsible for the disulfide bond formation, a series of Cys to Ser mutants has been constructed and the enzymatic activity was measured. Based on the results, we assumed that the first cysteine (Cys349) might be involved in disulfide bond mainly with the second cysteine (Cys445) and result in active conformation.

• Journal of the Korean Applied Science and Technology
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• v.15 no.2
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• pp.77-81
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• 1998

Surface active properties of these aqueous Gemini surfactant solutions including surface tension, critical micelle concentration(cmc), foaming power, foam stability, emulsifying power and Krafft point were measured at given conditions. They showed excellent properties, being compared with conventional single-chain surfactants such as sodium dodecyl sulfonate(SDS). Their surface tensions in the aqueous solutions were decreased to $30{\sim}38$ mN/m, which is lower than 39 mN/m of SDS, and their cmc values evaluated by surface tension method were $2.8{\times}10^{-5}{\sim}3.3{\times}10^{-4}$ mol/L. These values were also much lower than that of SDS, $9.8{\times}10^{-3}$ mol/L. The foaming power and foam stability, especially decyl and dodecyl compounds, were good and the emulsifying power in benzene or soybean oil was also excellent. All of the synthesized Gemini surfactants possessed good water solubility and their Krafft points were all below $0^{\circ}C$. As results, DDED and DDOD, Gemini surfactants which were synthesized are expected to be applied as foamers, emulsifiers and so on.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.4
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• pp.524-535
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• 1994

The interaction and detergency between oily soil and surfactant solution were studied Samples used were tristearin, tripalmitin and their mixture as a triglyceride, myristic acid as a fatty acid and sodium dodecyl sulfate (SDS) as surfactant. The results were as follows: 1. The mixtures of model oily soils were formed of eutectic point and their melting point were lower than them of individual oily soils. 2. The formation of liquid crystalline (LC) phase was recognized in the triangle phase diagram for SDS~ water~model oily soil system. The areas of LC phase region were in the order of SHS~ water~myristir acid> SDS~ water~mixture of tristearin, tripalmitin and myristic acid (TS/TP/M)>SDS~water~mixture of tristearin and tripalmitin (TS/TP) 3. The LC phase region expanded to wide concentration range of SDS solution and high concentration range of model oily soil with increasing temperature. Particularity, the LC phase region expanded highly at $30~40^{\circ}C$ but when the temperature was elevated above $40^{\circ}C$, expanding tendency decreased. 4. In the system of myristic acid and TS/TP/M contacted with SDS solution, the LC phase was already formed at $28^{\circ}C$ and the region of the LC phase were expanded with increasing temperature. But in the system of TS/TP contacted with SDS solution, the LC phase was not formed in whole experiment temperature. 5. The detergency of myristic acid was very high ann it was recognized that the formation of the LC phase played an important role in the detergency. The detergency of TS/TP was very for low, but when TS/TF was mixed with myristic acid, the detergency of TS/TP increased. It is supposed that the LC phase was formed butween SDS solution and myristic acid promoted to penetration of SDS solution into the inner parts of TS/TP.

• Analytical Science and Technology
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• v.6 no.1
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• pp.1-8
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• 1993

The purpose of this study is to investigate the elution behavior of monosubstituted phenols and benzenes in micellar liquid chromatographic system, $C_{18}$ column-anionic surfactant, sodium dodecyl sulfate(SDS). The partition coefficients between the micellar pseudophase-water and modified stationary phase-water are calculated by the relationship between solute retention and micellar mobile phase(SDS) composition. The free energy of transfer of solute from water to micelle is also calculated from these values. There is a direct correlation between the hydrophobicity parameters in MLC and corresponding partition data for 1-octanol-water, which indicates that the hydrophobicity of molecules plays an important role in the partition for both systems and that quantitative structure activity relationships(QSAR) are available from studies on micellar partition. The other purpose of this study is to investigate methylene selectivity of alkyl homologous series through correlation between retention and the number of carbons. The correlation between hydrophobicity parameters in MLC and 1-octanol-water partition data was also observed when n-propanol was as a modifier in the mobile phase.