• Analytical Science and Technology
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• v.10 no.2
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• pp.83-90
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• 1997

In this paper, optimum extraction condition for berberine which is the indan companent of Coptidis rhizoma was examined at various conditions in the aspect of temperature, solvent and time followed by quantitation with reversed phase HPLC. The efficiency for extraction has been shown the best at $60^{\circ}C$ with 2~3 hours reflux time in methanol or acetic acid. Any significant effect can not be shown from the addition of SLS to extraction solvent.

• 한국해양학회지
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• v.22 no.4
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• pp.271-278
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• 1987

Attempts were made to elucidate the responsible toxin in mussel Mytilus sp. which caused a food pisoning incident in March 1986 in Pusan, Korea. Two persons were dead and 15 persons intoxicated in the incident. The mid-gut glands of the mussel collected were extracted with dichlorlmethane, filtered through a Diaflo ulteafiltration membrane, and then purified by chromatography on Bio-Gel P-2 and Bio-Rex 70. The toxic fractions obtained were analysed by electrophoresis, TLC and ion-pairing reversed phase HPLC analyses. The results showed that the fractions contained GTW$\_$1-4/ as the major component, along with neoSTX, PX$\_$1,2/ as the minor. It was concluded from these results that the causative mussel toxin of the above food poisoning was PSP.

• Natural Product Sciences
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• v.12 no.1
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• pp.55-61
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• 2006

A description of simple, isocratic and precise reversed phase HPLC methods is given for simultaneous quantification of pholcodine and ephedrine hydrochloride together with either carbinoxamine maleate or terfenadine in antitussive-antihistaminic oral pharmaceutical formulations. Separations were carried out on X-Terra and symmetry shield C18 column $(250\;{\times}\;4.6\;mm,\;5\;{\mu}m)$. The used isocratic elution systems were either $0.02\;M\;KH_2PO_4-acetonitrile$ in the ratio of 75 : 25 and pH adjusted to 7.70 with orthophosphoric acid or sodium hydroxide, for syrup (method A), or 0.02 octanesulphonic acid sodium salt solution-acetonitrile-acetic acid in the ratio of 75 : 25 : 0.5 for suspension (method B). The elution of both mixtures was achieved with a flow rate of 1 ml/min. Detection was carried out by UV absorbance at wavelengths of 220 and 250 nm for syrup and suspension, respectively. The quantification of the components in synthetic mixtures and actual syrup and suspension were calculated using the internal standard technique with metoclopramide HCl and codeine phosphate as internal standards (IS), respectively. The methods, for both mixtures, were validated and met all the requirements for the quality control analysis recommended by FDA and ICH.

• Korean Journal of Pharmacognosy
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• v.37 no.4 s.147
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• pp.241-245
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• 2006

Morinda officinalis How. (Rubiaceae) has been used as tonic, warming, sex impulse and anti-inflammatory agents. Two known anthraquinones, rubiadin-1-methyl ether (I) and rubiadin (II) were isolated from root of M. officinalis. Their structures were identified using NMR and literature comparisons. The contents of I in eighteen M. officinalis were evaluated by HPLC-PDA. Chromatography was performed using a reversed-phase system with Luna $C_{18}$ (2) column and acetonitrile-water (50:50, v/v) with a flow rate of 1.0 mL/min under UV 280 nm. Under these conditions, the content of rubiadin-1-methyl ether was 0.013%.

• The Plant Pathology Journal
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• v.16 no.4
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• pp.189-199
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• 2000

To search for the antifungal substances, various actino-mycete isolates were obtained from various soils of Korea using plate dilution method on the humic acid vitamin agar plates. In the screening procedures using a dual culture method, 32 actionomycete isolates were selected, which showed the inhibitory activity against mycelial growth of plant pathogenic fungi Altirnaria mali, Colletotrichum gloeosporides, Fusarium oxysporum f.sp. cucumerinum, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. Bioassay of the crude extracts from culture filtrates and mycelial mets revealed that 12 antagonistic actionomycetes produced highly active antifungal substances. Actinomycete strain S5-55 which showed the substantial antifungal activity against the tested fungi was selected for production of the antifungal substances. Based on the cytochemical and morphological characteristics, strain S5-55 was identified as a Streptomyces species. The results of the numerical identification using the TAXON program confirmed that Streptomyces strain S5-55 was identical with Streptomyces humidus including in TAXON major cluster 19. The production of antifungal substance was most favorable when S. humidus strain S5-55 was cultivated for 10 dats on soluble starch broth supplemented with $K_2$HPO$_4$. The antifungal substances active against the plant pathogenic fungi P. capsici and M. grisea were partially purified using $\textrm{C}_{18}$ reversed-phase column chromatography.

• BMB Reports
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• v.32 no.6
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• pp.567-572
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• 1999

We have previously shown that a DNA fragment is responsible for the anticoagulatory effect of an earthworm, Lumbricus rubellus. The anticoagluant increased the activated partial thromboplastin time (APTT) and also inhibited the thrombin activity observed with either N-${\alpha}$-p-tosyl-L-arginine methyl ester (TAME) or H-D-phenyl-alanyl-L-pipecoil-L-arginine-p-nitroanilide (S-2238). Since trypsin digestion of the anticoagulant further increased the APTT, the possible presence of a regulatory protein for the anticoagulatory DNA was investigated by digesting the anticoagulant with trypsin and isolating the DNA fragment with C4-reversed phase HPLC. The DNA fragment lacking a regulatory protein was eluted in the flow-through fraction, and analyzed with thrombin and activated factor X. Activated factor X activity was more strongly inhibited than thrombin activity. For DNA digestion, we treated the anticoagulant with DNase and purified the DNA-binding protein with a FPLC Resource-S cation exchange column. The regulatory protein, with an $M_r$ of 55.0 kDa, reduced the anticoagulatory effect of the DNA fragment.

• BMB Reports
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• v.28 no.2
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• pp.87-93
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• 1995

To investigate the biological functions of the EGF-like domain of mouse betacellulin (BTC), mouse BTC(33-80), a 48-residue peptide corresponding to the EGF-like domain, was synthesized by stepwise solidphase methods using a 9-fluorenylmethoxycarbonyl (Fmoc) strategy. The homogeneity of synthetic mouse BTC(33-80) was confirmed by analytical reversed phase (RP)-HPLC, amimo acid analysis, and fast atom bombardment mass spectrometer (FAB-MS). Three disulfide bond pairings of synthetic mouse BTC(33-80) were established by amino acid analysis of cysteine-containing fragments derived from thermolytic digestion. These were consistent with the pairings of EGF and transforming growth factor ($TGF-{\alpha}$). The EGF-Iike domain of mouse BTC showed equipotent activity in both EGF-receptor binding on A-431 epidermoid carcinoma cells, and mitogenesis on NIH-3T3 fibroblast cells, as compared with authentic h-EGF. Results suggest that the EGF-Iike domain of BTC plays a significant role in mitogenic activity with an EGF-receptor mediated system.

• Carbon letters
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• v.4 no.3
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• pp.111-116
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• 2003

Carbon/carbon composites were developed using PAN based carbon fibres and phenolic resin as matrix in different volume fractions and heat treated to temperatures between $1000^{\circ}C$ to $2500^{\circ}C$. Although both the starting precursors are nongraphitizing hard carbons individually, their composites lead to very interesting properties e.g. x-ray diffractograms show the development of graphitic phase for composites having fibre volume fractions of 30~40%. Consequently the electrical resistivity of such composites reaches a value of $0.8\;m{\Omega}cm$, very close to highly graphitic material. However, it was found that by increasing the fibre volume fraction to 50~60%, the trend is reversed. Optical microscopy of the composites also reveals the development of strong columnar type microstructure at the fibre (matrix interface due to stress graphitization of the matrix. The study forcasts a unique possibility of producing high thermal conductivity carbon/carbon composites starting with carbon fibres in the chopped form only.

• Journal of Pharmaceutical Investigation
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• v.24 no.1
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• pp.1-9
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• 1994

In order to study systemic peptide delivery through the ocular route, the stabilities of methionine enkephalin (Met-Enk) and $[D-ala^2]-methionine$ enkephalinamide (YAGFM) in the corneal extracts of rabbits were investigated using reversed phase HPLC. Met-Enk was found to be hydrolyzed most rapidly in the corneal epithelium, but YAGFM was relatively stable. Aminopeptidases appeared to contribute over 60% to the degradation of Met-Enk and the degradation rate of Met-Enk followed the first order kinetics. The half-lives of Met-Enk in the extracts of the corneal epithelium and endothelium were 36 and 673 min, respectively. From the effects of enzyme inhibitors, it was found that the application of the mixture of amastatin, thimerosal and EDTA was very useful for the inhibition of peptide degradation.

• The Transactions of the Korea Information Processing Society
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• v.3 no.4
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• pp.877-882
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• 1996

The effects of periodic and chaotic behaviour in the Bonhoeffer-Van der Pol (BVP) oscillation of the nerve membrane driven by a periodic stimulating current A1 coswtare investigated through hardware implementation.For hardware implementation of the BVP model. real element values were escaled with computer simulation results to determine the parameter real value.As the parameter A1 varied in the range 0 to 1.3, the BVP model showed an ordinary and reversed period-doubling cascade and a chaotic state. At the low driving amplitude ofa1 the period-doubling showed and at the high driving amplitude of A1 the chaotic state occured. To analyse the BVP model for chaotic behaviour Phase Plane, Time series are used to verify that properties.