• Biomaterials and Biomechanics in Bioengineering
• /
• v.1 no.2
• /
• pp.95-104
• /
• 2014

The objective of this study was to evaluate the cytotoxicity of poly (lactic acid) (PLA) nanoparticles. We used a water-soluble, amphiphilic phospholipid polymer, poly (2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (PMB30W), as a stabilizer for the PLA nanoparticles. The PLA nanoparticles and PMB30W-modified PLA (PLA/PMB30W) nanoparticles were prepared by evaporating tetrahydrofuran (THF) from its aqueous solution. Precipitation of the polymers from the aqueous solution produced PLA and PLA/PMB30W nanoparticles with a size distribution of $0.4-0.5{\mu}m$. The partial coverage of PMB30W on the surface of the PLA/PMB30W nanoparticles was confirmed by X-ray photoelectron spectroscopy (XPS) and dynamic light-scattering (DLS). A high-content automated screening assay (240 random fields per group) revealed that the PLA nanoparticles induced apoptosis in a mouse macrophage-like cell line (apoptotic population: 73.9% in 0.8 mg PLA/mL), while the PLA/PMB30W nanoparticles remained relatively non-hazardous in vitro (apoptotic population: 13.8% in 0.8 mg PLA/mL). The reduction of the apoptotic population was attributed to the phosphorylcholine groups in the PMB30W bound to the surface of the nanoparticle. In conclusion, precipitation of PLA in THF aqueous solution enabled the preparation of PLA nanoparticles with similar shapes and size distribution but different surface characteristics. PMB30W was an effective stabilizer and surface modifier, which reduced the cytotoxicity of PLA nanoparticles by enabling their avoidance of the mononuclear phagocyte system.

• Journal of the Korean Chemical Society
• /
• v.27 no.6
• /
• pp.434-440
• /
• 1983

New procedures for the reduction of carboxylic acids, carboxylic acid salts, tertiary amides, and sulfoxides with sodium borohydride and triphenyl borate in tetrahydrofuran were developed. Thus carboxylic acids were reduced quantitatively in 6∼12 h at $25^{\circ}C$. Alphatic acid salts were quantitatively reduced to the corresponding alcohols in 6h at $25^{\circ}C$ whereas aromatic acid salts required 24h at $65^{\circ}C$. Tertiary amides were reduced to the corresponding amines in 88∼100% yields in 3∼6h at room temperature. Most sulfoxides examined were reduced to the corresponding sulfides in 98∼100% yields in 1∼6h at $25^{\circ}C$ and completely reduced at $65^{\circ}C$; however, diphenyl sulfoxide required 48h in a more vigorous condition.

• Journal of the Korean Chemical Society
• /
• v.22 no.1
• /
• pp.37-44
• /
• 1978

The effect of lithium chloride on the borane reduction of organic compounds was studied for three ketones, seven acid derivatives, three epoxides and cyclohexene in tetrahydrofuran at $0^{\circ}$. When compared with borane itself, borane-lithium chloride system enhanced the rates of reductions markedly of 2-heptanone, acetophenone, benzoyl chloride, phthalic anhydride, and three epoxides, whereas the reductions of benzophenone, four esters and cyclohexene showed little or no effect. $BH_3$-LiCl (1 : 0.1) reduced styrene oxide in 2 hr at $0^{\circ}$ to give 94.2 % yield of alcohols, 1-to 2-phenylethanol ratio being 60.8 to 39.2. And in the reduction of cyclohexene oxide, $BH_3$-LiCl (1 : 0.1) gave a quantitative yield of cyclohexanol in 2 hr at $0{\circ}$, however $BH_3$-LiCl (1 : 1) gave 58 % cyclohexanol and 42 % 2-chlorocyclohexanol. In the reduction of cyclohexene oxide, lithium nitrate showed no rate enhancement even when the salt was added in large excess. A formation of lithium chloroborohydride in the$BH_3$-LiCl system is suggested.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.39 no.2
• /
• pp.59-65
• /
• 2006

Fluoroquinolones are the most common group of antibacterial agents currently used in the Korean aquaculture industry, and use of these agents has been increasing steadily. High performance liquid chromatography (HPLC) with fluorescence detection was used for the simultaneous determination of five fluoroquinolones in fish and shellfish: ofloxacin (OFL), pefloxacin (PEF), norfloxacin (NOR), ciprofloxacin (CIP), and enrofloxacin (ENRO). Fish and shellfish muscle was homogenized, and protein, lipid, and low molecular weight pigments were then excluded from the homogenate. The final eluates were analyzed by HPLC equipped with a Shiseido UG-120 type C18 reverse-phase column ($4.6{\times}250 mm$, $5{\mu}m$) and a fluorescence detector (excitation at 280 nm, emission at 450 nm). The mobile phase was 0.1 M phosphoric acid and acetonitrile solution (91:9, v/v) and tetrahydrofuran (THF) was added to it at a rate of 5 mL per a liter of the mobile phase. Adequate chromatography separation was obtained using the above method. Average recoveries of fortified samples at levels from 0.05 to 0.5 mg/kg were $72.3{\pm}2.5-84.5{\pm}1.2%$ for OFL, $82.7{\pm}3.3- 109.3{\pm}7.5%$ for NOR, $85.3{\pm}6.6-116.0{\pm}7.9%$ for PEF, $76.0{\pm}4.3-109.3{\pm}12.4%$ for CIP, and $78.7{\pm}5.9-100.0{\pm}9.8%$ for ENRO. The limit of detection of OFL was $5{\mu}g/L$, the others were $1{\mu}g/L$. We concluded that the new analytical method was suitable for the determination of fluoroquinolones in fish and shellfish.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.26 no.3
• /
• pp.307-316
• /
• 2016

Objectives: In general, NIOSH method 5506 is most widely used for the occupational exposure measurement of PAHs, but 2-4 ring PAHs have poor desorption efficiency, especially for a filter. The purpose of this study was to determine a method to increase the desorption efficiency of 16-PAHs using an ultrasonic extraction procedure. Methods: Test samples prepared spiked XAD-2 tubes and PTFE filters in the range of $0.01-1.0{\mu}g/mL$ for desorption efficiency study. Four different extraction solvents, acetonitrile, acetone, tetrahydrofuran and dichloromethane, were tested in order to select the most suitable solvent for the extraction of the 16 PAHs. The addition of dimethyl sulfoxide and sonication time were considered in order to determine the method with the highest extraction efficiency. All samples were made in three sets and analysis was replicated seven times by HPLC. Results: Acetonitrile and acetone were the optimized as an extraction solvent and desorption efficiency of 2-ring PAHs such as naphthalene, acenaphthylene were increased 3~19% with dimethyl sulfoxide for XAD-2. Acetone was the best extraction solvent for PTFE filter and the desorption efficiency was increased 3~13% for 2- to 4-ring PAHs. The optimum sonication time was 60 minutes and desorption efficiency increased with extraction time. Conclusions: As a result, the best extraction solvent was acetone with dimethyl sulfoxide for ultrasonic extraction procedure and the desorption efficiency of this method was better than NIOSH 5506's. This study could be applied as a method for occupational exposure measurement of PAHs.

• Biomolecules & Therapeutics
• /
• v.20 no.5
• /
• pp.477-481
• /
• 2012

The rhizomes of Acorus gramineus have frequently been used in traditional medicine mainly for sedation as well as enhancing brain function. In this study, the anti-allergic activity of A. gramineus was investigated. The 70% ethanol extract of the rhizomes of A. gramineus was found to inhibit the allergic response against 5-lipoxygenase (5-LOX)-catalyzed leukotriene (LT) production from rat basophilic leukemia (RBL)-1 cells and ${\beta}$-hexosaminidase release from RBL-2H3 cells with $IC_{50}$'s of 48.9 and > $200{\mu}g/ml$, respectively. Among the 9 major constituents isolated, ${\beta}$-asarone, (2R,3R,4S,5S)-2,4-dimethyl-1,3-bis (2',4',5'-trimethoxyphenyl)tetrahydrofuran (AF) and 2,3-dihydro-4,5,7-trimethoxy-1-ethyl-2-methyl-3-(2,4,5-trimethoxyphenyl)indene (AI) strongly inhibited 5-LOX-catalyzed LT production in A23187-treated RBL-1 cells, AI being the most potent ($IC_{50}=6.7{\mu}M$). Against ${\beta}$-hexosaminidase release by antigen-stimulated RBL-2H3 cells, only AI exhibited strong inhibition ($IC_{50}=7.3{\mu}M$) while ${\beta}$-asarone and AF showed 26.0% and 39.9% inhibition at $50{\mu}M$, respectively. In addition, the ethanol extract of A. gramineus showed significant inhibitory action against the hapten-induced delayed hypersensitivity reaction in mice by oral administration at 200 mg/kg. Therefore, it is suggested that A. gramineus possesses anti-allergic activity and the constituents including ${\beta}$-asarone and AI certainly contribute to the anti-allergic activity of the rhizomes of A. gramineus.

• Applied Chemistry for Engineering
• /
• v.10 no.6
• /
• pp.822-827
• /
• 1999

The specific capacitance characteristics which were of the electric double layer capacitors(ELDC) made of phenol based activated carbon fiber(ACF) electrodes and organic electrolytes has been investigated with respect to different specific surface area of electrodes and different kinds of organic electrolytes. Throughout charge-discharge cell tests, it has been found that larger surface area and larger pore diameter of electrodes contribute to increase the specific capacitance. Binary mixture of organic solvent with propylene cabonate(PC) and tetrahydrofuran(THF) for 1 M-$LiClO_4$ electrolyte has a higher specific capacitance than single solvent of PC or mixed solvent with PC and diethyl cabonate(DEC). Also, even though 1 M-tetraethylamonium perchlorate(TEAPC) of organic electrolyte shows higher specific capacitance, it has longer charge time because of its lower ion mobility.

• Korean journal of food and cookery science
• /
• v.15 no.6
• /
• pp.611-617
• /
• 1999

Commercial soybean oil, which did not contain any antioxidant, were autoxidized at $60{\pm}2^{\circ}C$ for 79 days, and the changes of peroxide value(POV), thiobarbituric acid value(TBAV), conjugated dienoic acid(CDA) content, and fatty acid composition of the oil were studied during the 79 day-storage period. The samples with POV S of 0, 150, 300, 500, 450, 400 and 300 meq./kg oil were used for the test of mutagenic activity. The Ames test was carried out with and without metabolic activation. Bacterial strains used in this study were the histidine auxotrophic strains of S. typhimurium TA100, TA1535, and TA102 for the detection of base pair, and TA98 and TA1537 for frame shift mutations. Each series of samples was disso1ved in tetrahydrofuran(inhibitor free) and tested at doses ranging from 0.05 to 5 mg/plate. The autoxidized soybean oil increased significantly(p<0.05) the number of $His^+$ revertant colonies in cases of TA 98 with S9 mix, TA100 without S9 mix, 1535 and 1537 with and without S9, respectively. The samples having the highest peroxide values showed the strongest mutagenicity. It seemed that the amount of hydroperoxides in the oils was closely related to the mutagenic activity of the respective oils.

• Applied Chemistry for Engineering
• /
• v.31 no.5
• /
• pp.502-508
• /
• 2020

Dual drug-eluting stents (DES) is a primary treatment method for coronary arterial diseases in current interventional cardiology practice. However, their pathological results according to the sequence of coating of drugs have not been reported yet. The peptide-dopamine dissolved in acetonitrile was coated onto the Chonnam National University Hospital (CNUH) stent using an electrospinning coating machine. For secondary coating (e.g., sirolimus coating, designated as SPS), sirolimus (SRL) and poly lactic-glycolic acid (PLGA) were mixed in tetrahydrofuran (THF), and the solution was then coated on the CNUH stent that had underwent the primary peptide coating using an electrospinning and spray technique. Next, the peptide-dopamine was coated on the SRL-PLGA coated stent (PSS). In this study, it was confirmed that endothelialization was promoted without being significantly affected by the coating order (SPS or PSS). The sequence of drug and peptide coating may affect the development of restenosis and PSS was effective in the prevention of restenosis compared to that of using SPS.

• Journal of the Korean Chemical Society
• /
• v.36 no.1
• /
• pp.57-65
• /
• 1992

The method for investigating the retention behavior and separation optimization was studied to develop a reversed-phase liquid chromatography of eleven thiocarbamates that are used as herbicides. As an isocratic elution system, the statistical simplex technique was applied to find the optimum separation conditions. The resolution was quantitatively evaluated by using COF and ORM method. For thiocarbamate herbicides in which the elution order varies dramatically with solvent composition, the ORM method gave better result than the COF method. For the solvent composition of mobile phase in the ORM method, the ratio of methanol : acetonitrile : tetrahydrofuran : water was 16 : 29 : 2 : 53. Also in this research, an adjusted COF $(\overline{COF})$ method was proposed to rectify the defect in the current COF method, and the compositional ratio of mobile phase containing methanol : acetonitrile : water was 29.5 : 21.5 : 49.0 result of which is similar to that obtained by the ORM method.