• Korean Chemical Engineering Research
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• 제58권4호
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• pp.635-641
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• 2020

이 연구에서는 에틸렌글리콜과 염이 포함된 메탄 하이드레이트의 상평형과 형성 거동을 측정하였다. 염의 종류로는 염화나트륨(NaCl), 브롬화나트륨(NaBr), 아이오딘화나트륨(NaI)을 이용하였으며, 272~283 K의 온도 범위와 3.5~11 MPa의 압력범위에서 상평형 조건을 확인하였다. 5 wt% NaCl + 10 wt% MEG, 5 wt% NaBr + 10 wt% MEG, 5 wt% NaI + 10 wt% MEG의 순서로 메탄 하이드레이트의 억제 효과가 나타났음을 확인하였다. 에틸렌글리콜과 염이 포함된 메탄 하이드레이트의 형성 거동은 생성유도시간, 가스소모량과 성장 속도를 분석하여 확인하였다. 에틸렌글리콜과 염이 포함된 메탄 하이드레이트의 생성유도시간은 실험 조건에서 큰 차이를 보이지 않았지만, 에틸렌글리콜과 염의 첨가는 가스소모량과 성장 속도에 영향을 주었음을 확인할 수 있었다.

• Archives of Pharmacal Research
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• 제18권4호
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• pp.231-236
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• 1995

Effects of sodium salts of various monovalent inorganic anions on transdermal permeation of salicylic acid were investigated. In in-vitro experiment using a Franz-type diffusion cell and excisicylic acid were investigated. In-vitro experiment using a Franze-type diffusion cell and excised mouse skin, the permeation-enhancing activities of the sodium salts of inoraganic anions were rougly proportional to lyotropic Hofmeister serlling abilities of the anions l F/sup -/

• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.47.1-47.11
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• 2020

Objectives: The aim of this study was to assess the physicochemical properties, cytotoxicity and penetration into dentinal tubules of ChlorCid^TM Surf (3% sodium hypochlorite [NaOCl] with surfactant) in comparison to ChlorCid^TM (3% NaOCl without surfactant). Materials and Methods: The physicochemical properties evaluated were pH, surface tension, free available chlorine (FAC) and contact angle. Cytotoxicity was evaluated in L929 fibroblasts exposed to the solutions by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and neutral red assays. Assessment of penetration into dentinal tubules was performed by staining single-rooted permanent human teeth with crystal violet (n = 9), which were irrigated with the solutions and analyzed in cervical, middle and apical segments. Data were analyzed by one-way analysis of variance (ANOVA) and Tukey's post-test, 2-way ANOVA and Bonferroni's post-test or t-test (α = 0.05). Results: ChlorCid^TM Surf and ChlorCid^TM FAC values were close to those indicated by the manufacturer. ChlorCid^TM Surf showed lower surface tension and contact angle on dentin, and higher pH than ChlorCid^TM (p < 0.05). The penetration of ChlorCid^TM Surf was higher in cervical and middle segments, compared with ChlorCid^TM (p < 0.05). There was no difference in irrigant cytotoxicity (p > 0.05). Conclusions: ChlorCid^TM Surf showed lower surface tension, lower contact angle on root canal dentin, higher penetration into dentinal tubules and more alkaline pH, compared with ChlorCid^TM. However, both solutions showed similar cytotoxicity and FAC content.

• 대한화장품학회지
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• 제17권1호
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• pp.18-28
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• 1991

Spectral behaviors of cationic dye, crystal violet(CV), in aqueous solution and with varying concentrations of Triton X-100(TX-100), sodium dodecylsulfate (SDS) and cetyl trimethyl amonium bromide(CTAB) were studied. The characteristic changes of the absorption spectra observed in the dye-SDS interacting systems with the SDS concentration are analyzed. The behaviors of both a- and J-bands of the each componet dye suggest that the following four sequential steps are occurring : the formation of dye-SDS complex, the stacking of the dye molecules arising from the association of the dye-SDS complex, breaking of the dye stacking due to the formation of micelles, redistribution of the dye molecules in the surface of micelles at high SDS concentration.

• 대한화학회지
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• 제58권4호
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• pp.351-358
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• 2014

Anionic (sodium lauryl sulphate, NaLS) cationic (cetyl ammonium bromide, CTAB) and non-ionic (Tween-80) surfactants have been found to inhibit the rate of oxiadation L-proline and L-methionine by alkaline $KMnO_4$. A first order dependence of rate of oxidation was observed with respect to $MnO_4{^-}$. The order of reaction in substrate and alkali was found to be fractional nearby 0.65 and 0.55 in Aminoacid and $OH^-$, respectively. An aggregation/association between $MnO_4{^-}$ and surfactant has been confirmed spectrophotometrically. A mechanism, involving kinetically inactive [$MnO_4{^-}$ surfactant] aggregate and consistent with kinetic data, has been proposed. The effect of surfactants has been discussed in terms of hydrophobic and electrostatic interactions.

• 한국미생물·생명공학회지
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• 제25권3호
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• pp.335-337
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• 1997

In this study, we show a convenient MTT assay for detect the susceptibility of yeast-like form of Trichosporon beigelii against antifungal agents. This assay was developed based on mitocondrial respiration by determining reduction of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to formazan. Cells of T beigelii are seeded into 96-well microtiter plates, and antifungal agents, amphotericin B, magainin and CA-ME hybrid peptide were added with various concentrations. After 24 hr incubation, MTT was added, then incubations were continued for 4 hr. Formazan formation was quantified photometrically after extraction of the formazan with acid sodium dodesyl sulfate (SDS). From this assay, we could obtained MICs of antifungal agents against T. beigelii. The presented method can easily be used as an effective methods to assess the antiftingal action of various agents on yeasts with minimal amounts of antifungal agents.

• 한국응용과학기술학회지
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• 제21권1호
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• pp.17-23
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• 2004

Silver bromide particles from 50 to 200${\AA}$ in diameter are prepared by mixing two microemulsions contaning the precursor salts $AgNO_3$ and KBr. The microemulsions are composed of AOT(bis(2-ethylhexyl) sodium sulfosuccinate), n-heptane and water. The particle diameters are measured on photomicrographs obtained by transmission electron microscopy. The size of the particles is generally larger than that of the water cores. The influence of both the concentration of precursor salts in the water cores of the microemulsoin and the size of these water cores on the size of the particles has been studied.

• 대한기계학회논문집A
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• 제30권2호
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• pp.179-186
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• 2006

Dielectrophoresis has received considerable attention for separating nanotubes according to electronic types. Here we examine the effects of surface conductivity of semiconducting single-walled carbon nanotubes (SWNT), induced by ionic surfactants, on the sign of dielectrophoretic force. The crossover frequency of semiconducting SWNT increases rapidly as the conductivity ratio between the particle and medium increases, leading to an incomplete separation of ionic surfactant suspended SWNT at an electric field frequency of 10 MHz. The surface charge of SWNT is neutralized by an equimolar mixture of anionic surfactant sodium dodecyl sulfate (SDS) and cationic surfactant cetyltrimenthylammonium bromide (CTAB), resulting in negative dielectrophoresis of semiconducting species at 10 MHz. A comparative Raman spectroscopy study shows a nearly complete separation of metallic SWNT.

• Macromolecular Research
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• 제13권3호
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• pp.229-235
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• 2005

Various alkoxyamine initiators for nitroxide mediated radical polymerization (NMRP) were prepared in high yields by a simple substitution reaction of nitroxide anions with benzyl bromide. The required nitroxide anions were easily generated by treating either nitroxide free radicals or hydroxy amine with an alkali metal such as sodium or potassium in THF. This method is both practical and efficient, since the ionic conditions prevent other side reactions from occurring, such as the self-coupling or oligomerization reactions that are observed in the case of radical trapping conditions. To demonstrate the utility of the resulting alkoxyamine initiators, end- and telechelic-alkoxyamine PEG macroinitiators derived from the alkoxyamines were synthesized by a simple chemical modification, and used for the preparation of PEG-b-PS and PS-b-PEG-b-PS block copolymers by NMRP.

• Food Science and Biotechnology
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• 제14권1호
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• pp.131-136
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• 2005

The selective extraction behavior of lactoferrin (Lf) from whey protein mixture was examined using reverse micelles formed by the cationic surfactant, cetyldimethylammonium bromide (CDAB). The major whey proteins, including ${\beta}$-lactoglobulin, ${\alpha}$-lactalbumin and bovine serum albumin, were solubilized from aqueous phase to organic phase while Lf was recovered in the aqueous phase. The solubilization behaviors of the proteins were manipulated by the process parameters such as the pH and salt concentration of the aqueous phase and the surfactant concentration in the organic phase. Efficient forward extraction was achieved with sodium borate buffer (50 mM, pH 9) containing 50 mM KCl and organic phase containing 100 mM CDAB. Based on SDS-PAGE and densitometry, about 96% of the initial Lf remained in the aqueous phase after forward extraction. The dialyzed Lf fully maintained its bacteriostatic activity against E. coli O157:H7.