• Proceedings of the PSK Conference
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• 2002.10a
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• pp.394.2-394.2
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• 2002

A sensitive and selective reversed-phase LC-ESI-MS method to quantitate pseudoephedrine in human plasma was developed and validated. Phenacetin was used as an internal standard. Samples were prepared simply by acetonitrile precipitation without an evaporation step. Chromatographic separation was achieved on a XTerra MS C18 column ($150{times}2.1$ mm I.D.. 3.5 $\mu\textrm{m}$ particles). using gradient elution with 0.5% (v/v) trifluoroacetic acid (TFA) in water and 0.5% (v/v) TFA in methanol at a flow-rate of 0.1 ml/min. (omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.398.2-398.2
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• 2002

A column switching HPLC assay was developed to allow the separation and quantitation of cetirizine in human plasma by ultraviolet (UV) detection. Plasma samples were prepared by liquid-liquid extraction. After drying, the residue was reconstituted in 20 mM phosphate buffer (pH 2.8) containing 15% acetonitrile. The samples were initially injected onto a clean-up Capcell Pak MF C18 column. (50 mm $\times$ 4.6 mm I.D.), and the chromatographic region containing the peaks of interest was followed in an analytical C18 microcolumn (250 mm$\times$1.5 mm I. D.) via column switching device. (omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.278.2-278.2
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• 2003

A column-switching semi-micro HPLC method with fluorescence detection was developed for the direct analysis of rebamipide in human plasma. Plasma was filtered through a 0.45 $\mu\textrm{m}$ membrane filter and 5 ${\mu}\ell$ of the filtrate was directly injected onto the pre-column. After elution of the plasma proteins to waste, the retained rebamipide and internal standard(ofloxacin) were transferred to a C18 semi-microcolumn (5$\mu\textrm{m}$, 150 ${\times}$2.0mm) where they were separated using acetonitrile-1.4％ acetic acid (40:60, v/v) as mobile phase. (omitted)

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.539-545
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• 2014

Styrene-acrylamide co-polymer was immobilized on porous partially sub-$2{\mu}m$ silica monolith particles and inner surface of fused silica capillary ($50{\mu}m$ ID and 28 cm length) to result in ${\mu}LC$ and CEC stationary phases, respectively, for separation of anomeric D-glucose derivatives. Reversed addition-fragmentation transfer (RAFT) polymerization was incorporated to induce surface polymerization. Acrylamide was employed to incorporate amide-functionality in the stationary phase. The resultant ${\mu}LC$ and CEC stationary phases were able to separate isomers of D-glucose derivatives with high selectivity and efficiency. The mobile phase of 75/25 (v/v) acetonitrile (ACN)/water with 0.1% TFA, was used for HPLC with a packed column (1 mm ID, 300 mm length). The effects of pH and ACN composition on anomeric separation of D-glucose in CEC have been examined. A mobile phase of 85/15 (v/v) ACN/30 mM sodium acetate pH 6.7 was found the optimized mobile phase for CEC. The CEC stationary phase also gave good separation of other saccharides such as maltotriose and Dextran 1500 (MW~1500) with good separation efficiency (number of theoretical plates ~300,000/m).

• Journal of the Korean Chemical Society
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• v.24 no.1
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• pp.8-14
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• 1980

Solvolysis rate constants for methylchloroformate, $CH_3O$(CO)Cl, methylthiono-chloroformate, $CH_3O$(CS)Cl, and methylthiolchloroformate, $CH_3S$(CO)Cl, have been determined conductometrically in acetone-water and acetonitrile-water mixtures, and activation parameters, ${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$, have been derived. Results show that in water-rich regions the order of rate increases as $$CH_3O(CO)Cl while in dipolar aprotic solvent-rich region this order reverses. The plots of log k vs. solvent parameters, Y, $\frac{D-1}{2D+1}$ and log($H_2$) show that the order of rate increase in water-rich region is the results of increase in $S_N1$ character. It is concluded that $CH_3S$(CO)Cl solvolyzes via $S_N1$ mechanism whereas $CH_3O$(CO)Cl reacts via $S_N2$ and $CH_3O$(CS)Cl via intermediate mechanism in water-rich region.

• Journal of Periodontal and Implant Science
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• v.38 no.1
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• pp.41-50
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• 2008

Purpose: Bone morphogenetic protein-2(BMP-2) has been shown to possess significant osteoinducitve potential. There have been attempts to overcome a limitation of mass production, and economical efficiency of BMP. The aim of this study was to produce recombinant human BMP-2(rhBMP-2) from E. coli in a large scale and evaluate its biological activity. Materials and Methods: The E.coli strain BL21(DE3) was used as a host for rhBMP-2 production. Dimerized rhBMP-2 was purified by affinity chromatography using Heparin column. To determine the physicochemical properties of the rhBMP-2 expressed in E. coli, we examined the HPLC profile and performed Western blot analysis. The effect of the purified rhBMP-2 dimer on osteoblast differentiation was examined by alkaline phosphatase (ALP) activity and representing morphological change using C2C12 cell. Results: E. coli was genetically engineered to produce rhBMP-2 in a non-active aggregated form. We have established a method which involves refolding and purifying a folded rhBMP-2 dimer from non-active aggregates. The purified rhBMP-2 homodimer was characterized by SDS-PAGE as molecular weight of about 28kDa and eluted at 34% acetonitrile, 13.27 min(retention time) in the HPLC profile and detected at Western blot. The purified rhBMP-2 dimer stimulated ALP activity and induced the transformation from myogenic differentiation to osteogenic differentiation. Conclusion: rhBMP-2 was produced in E. coli using genetic engineering. The purified rhBMP-2 dimer stimulated ALP activity and induced the osteogenic differentiation of C2C12 cells.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.356-356
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• 2006

The use of renewable feedstock is an important issue to reduce the fossil fuel consumption. In this contribution, we report the cationic ring-opening polymerization of a 2-oxazoline monomer with soybean fatty acid side chains (SoyOx) under microwave irradiation. Kinetic experiments were performed to investigate the livingness of the polymerization in both acetonitrile and in the absence of solvent. In addition, both block and statistical copolymers were prepared using the SoyOx monomer. The synthesized (co)polymers were crosslinked under UV-irradiation resulting in insoluble polymeric materials and core-crosslinked micelles.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2274-2278
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• 2011

Verapamil is a calcium channel blocker and is classified as a class IV anti-arrhythmic agent. It is used in the control of supra ventricular tachyarrhythmias, and in the management of classical and variant angina pectoris. It is also used in the treatment of hypertension and used as an important therapeutic agent for angina pectoris, ischemic heart disease, hypertension and hypertrophic cardiomyopathy. Verapamil commonly co-administered with NSAIDs (non-steroidal anti-inflammatory drugs) i.e. diclofenac sodium, flurbiprofen, Ibuprofen, mefanamic acid and meloxicam. A simple and rapid RP-HPLC method for simultaneous determination and quantification of verapamil and NSAIDs was developed and validated. The mobile phase constituted of acetonitrile: water (55:45) whose pH was adjusted at 2.7 and pumped at a flow rate of 2.0 mL $min^{-1}$ at 230 nm. The proposed method is simple, precise, accurate, low cost and least time consuming for the simultaneous determination of verapamil and NSAIDs which can be effectively applied for the analysis of human serum.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.220.1-220.1
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• 2003

A sensitive and selective liquid chromatographic method for the determination of carvedilol in human plasma was developed and validated. Analytes were separated on a XTerra C18 column with acetonitrile-methanol-30 mM KH$_2$PO$_4$ (pH 2.5) (20 : 20 : 60, v/v/v), as mobile phase. One mL plasma were pipetted into glass tubes and spiked with 0.05 mL of internal standard solution. After adding 7 mL of diethyl ether, the plasma sample was then shacked for 15 min. A centrifuged upper layer was back-extracted with 150 uL of 0.05 M sulfuric acid. (omitted)

• Current Optics and Photonics
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• v.1 no.3
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• pp.247-251
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• 2017

In this study, an ultraviolet Raman spectrometer was designed and fabricated to detect chemical contamination on the ground. The region of the Raman spectrum that indicated the characteristics of the chemicals was $350-3800cm^{-1}$. To fabricate a Raman spectrometer operating in this range, the layout and angle of optical components of the spectrometer were designed using a grating equation. Experimental devices were configured to measure the Raman spectra of chemicals based on the fabricated Raman spectrometer. The wavenumber of the spectrometer was calibrated by measuring the Raman spectrum of polytetrafluoroethylene, $O_2$, and $N_2$. The spectral range of the spectrometer was measured to be 23.46 nm ($3442cm^{-1}$) with a resolution of 0.195 nm ($30.3cm^{-1}$) at 253.65 nm. After calibration, the main Raman peaks of cyclohexane, methanol, and acetonitrile were found to be similar to the references within a relative error of 0.55%.