• Natural Product Sciences
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• v.13 no.4
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• pp.378-383
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• 2007

Phenathrene derivatives, such as batatasins, are well-known constituents in Dioscorea Rhizoma. Although phenanthrenes have been reported as representative compounds in this plant, standard markers for quality control have been focused on the polar constituents (saponins and purine derivatives). Herein, simple, rapid and reliable HPLC method was developed to determine 3,5-dimethoxyphenanthrene-2,7-diol (DMP) and batatasin-I (BA-I) as non-polar standard maker compounds of Dioscorea Rhizoma. DMP and BA-I were analyzed under optimized HPLC conditions [column: Columbus $5{\mu}$ C18 100A ($30{\times}4.6mm$ i.d., $5{\mu}m$; mobile phase: $H_2O$ with 0.025% $CH_3COOH$ (v/v) for solvent A and $CH_3CN$ with 0.025% $CH_3COOH$ (v/v) for solvent B, gradient elution; flow rate: 2 mL/min; detection: 260 nm), and each experiment was finished within 13 min. Good linearity was achieved in the range from 0.5 to $10.0{\mu}g/mL$ for each compound, and intra- and inter-day precision were in the acceptable levels. The recovery test were performed with three different Dioscorea Rhizoma samples (D. opposita, D. batatas and D. japonica), and showed its accuracy values in the range of 97.2 - 102.8% for three different concentrations of DMP and BA-I. The content levels of DMP and BA-I were ranged under 0.0020%. These results demonstrated that amounts of DMP and BA-I are easily determined with conventional HPLC-UV-DAD method although the content levels were lower than those of saponins and allantoin in Dioscorea Rhizoma. This HPLC method could be used for quality control of various Dioscorea preparations.

• Water for future
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• v.15 no.3
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• pp.49-55
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• 1982

The purpose of this study is to examine the methods of estimation, comparing U.S. SCS method and $\Phi$-index with effective rainfall. And also comparision was made among SCS method, Chow method and Mockus method as to the peak discharge of design storm hydrograph by small river basin. Hydrological data of the Shin river basin which was used in this study and the results of study are as follow; 1) As a result of applying the SCS method to determine the effective rainfall out of total rainfall, it turned out that the everage CN of the basin as obtained by the analysis of hydrologic soil-cover complex was varied as follows; AMC-I was 27.9%, AMC-II 16.4%, AMC-III 8.1% less than the value given by SC method using discharge measurement. 2) The comparision of effective rainfall by the ungaged SCS method with that of gauged $\Phi$-index method showed that the $\Phi$-index method showed that the $\Phi$-index method gives large value by 4.7% to those given by hydrograph. The result of analysis by the SCS method resulted in great difference from discharge measurement. 3) The comparision of SCS method, Chow method, and Mockus method showed that dimensionless hydrograph of SCS method and Chow method were close to the peak discharge of the gauged unit hydrograph, while the other methods gave far different results. 4) Attempts were made, for a better adaptation to the Shin river basin, to introduce lag time formula constant of dimensionless hydrograph of the SCS method by using the peak discharge of the gauged flow hydrograph.

• Journal of Chest Surgery
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• v.42 no.5
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• pp.588-596
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• 2009

Background: To clarify the effect of hypoxia on vascular contractility, we tried to show whether hypoxia induced the release of endothelium-derived relaxing factor (EDRF) and the nature of the underlying mechanism for this release. Material and Method: Isometric contractions were observed in rabbit aorta, and the released EDRF from the rabbit aorta was bioassayed by using rabbit denuded carotid artery. The intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) in the cultured rabbit aortic endothelial cells was recorded by a microfluorimeter with using Fura-2/AM. Hypoxia was evoked to the blood vessels or endothelial cells by eliminating the $O_2$ in the aerating gases in the external solution. Chemical hypoxia was evoked by applying deoxyglucose or $CN^-$. Result: Hypoxia relaxed the precontracted rabbit thoracic aorta that had its endothelium, and the magnitude of the relaxation was gradually increased by repetitive bouts of hypoxia. In contrast, hypoxia-induced relaxation was not evoked in the aorta that was denuded of endothelium. In a bioassay experiment, hypoxia released endothelium-derived relaxing factor (EDRF) and the release was inhibited by L-NAME or the $K^+$ channel blocker tetraethylammonium (TEA). In the cultured endothelial cells, hypoxia augmented the ATP-induced increase of the intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) and this increase was inhibited by TEA. Furthermore, chemical hypoxia also increased the $Ca^{2+}$ influx. Conclusion: From these results, it can be concluded that hypoxia might induce the release of NO from rabbit aortic endothelial cells by increasing $[[Ca^{2+}]_i$.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2001.12a
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• pp.126-126
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• 2001

The Rhus verniciflua contains alkly(en)-catechol type allergens with a saiurated or unsaturated alkly chain of 15 or 17 carbon atoms. It has been recognized as an extremely active allergen causing skin reactions similar In poison ivy. The allergic contact dermatitis induced by the urushiol is known to be mediated be T lymphocytes whicht specifically recognize the hepten urushiol. Therefore. direct use of this plant as a medicinal purpose might imply a considerable hazard in Korea. In this study, using the established method for the detoxification from the stem bark of Rhus verniciflua, an strong antioxidant substance was isolated and characterized DPPH (diphenypricryl hydrazyl) assay measures hydrogen atom-donating activity and hence provides a measure of free radical scavenging antioxidant activity. DPPH, a purple-colored stable free radical, is reduced to yellow-colored diphenylpicryl hydrazine by antioxidants to deducing agents. Antioxidative effects of the water extract from RV were measured by DPPH assay. Twenty microliters of the extract was added to 1ml of 100mM DPPH solution in ethanol The mixture was shaken and left to stand for 10min at room temperature. The crude water extracts was purified by using HPLC method with a DEAE (anionic type), CN, ODS column. The purified compound remained stable at pH 3.0-6,0, but unstable above pH 6.5. It was stable heat at 10$0^{\circ}C$ for 4 hours, but still had about 80% of residual activity after treatment at 10$0^{\circ}C$ for 5 hours. The elemental composition of the HR-EI mass spectrum at m/z 170.02 was estimated the empirical formula as $C_{7}$ $H_{6}$ $O_{5}$. $C_{10}$ $H_4$ $O_2$N$_1$, $C_{5}$ $H_4$ $O_4$N$_3$, $C_{8}$$H_2O$$_1$N$_4$. In antimicrobial test, no inhibition was observed against Gram-positive and negative bacteria. This compound was stronger than that of commercial antioxidant by DPPH test, such as BHT, BHC at the same concentration (20$\mu$g/ml).ml).

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.2
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• pp.67-73
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• 2015

The microcystin is a cyclic heptapeptide from metabolites of cyanobacteria in the genera mycrocystis, anabaeba as a result of eutrophication. It has been known that microcystin-LR is a potent inhibitor of the catalytic subunits of protein phosphatase-1 (PP-1) as well as powerful tumor promoter. The active site of microcystin actually has two metal ions $Fe^{2+}/Zn^{2+}$ close to the nucleophilic portion of PP-1-microcystin complex. We report the isolation and purification of this microcystin-LR from cyanobacteria (blue-green algae) obtained from Daechung Dam in Chung-cheong Do, Korea. Microcystin-LR was extracted from solid-phase extraction (SPE) sample preparation using a CN cartridge. The cyanobacteria extract was purified to obtain microcystin-LR by HPLC method and identified by LC/MS. The detail structural studies that can elucidate the possible role of monovalent and divalent metal ions in PP-1-microcystin complexation were carried out by utilizing molecular dynamics. Conformational changes in metal binding for ligands were monitored by molecular dynamic computation and potential of mean force (PMF) using the method of the free energy perturbation. The microcystin-metal binding PMF simulation results exhibit that microcystin can have very stable binding free energy of -10.95 kcal/mol by adopting the $Mg^{2+}$ ion at broad geometrical distribution of $0.5{\sim}4.5{\AA}$, and show that the $K^+$ ion can form a stable metal complex rather than other monovalent alkali metal ions.

• Water for future
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• v.10 no.1
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• pp.53-70
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• 1977

The analysis performed here is aimed to increase the familiarity of hydrologic process especially for the small basins which are densely gaged. Kyung An and Mu Shim river basins are selected as a representative basin according to the criteria which UNESCO has established back in 1964 and being operated under the auspice of Ministry of Construction. The data exerted from these basins is utilized for the determination of characteristics of procipitation and runoff phenomena for the small basin, which is considered as a typical Korean samall watershed. The study found that the areal distribution of preciptation did not show any significant deviation from the point rainfall. Since the area studied is less than 20 km#, the pointrainfall may be safely utilized as a representative value for the area. Also the effect of elevation on the precipitation has a minor significance in the small area where the elevation difference is less than 200m. The methodology developed by Soil Conservation Service for determination of runoff value from precipitation is applied to find the suitability of the method to Korean river basin. The soil cover complex number or runoff curve number was determined by comsidering the type of soil, soil cover, land use and other factors such as antecedent moisture content. The average values of CN for Kyung An and Mushim river basins were found to be 63.9 and 63.1 respectively under AMC II, however, values obtained from soil cover complex were less than those from total precipitation and effective precipitation about 10-30%. It may be worth to note that an attention has to be paid in application of SCS method to Korean river basin by adjusting 10-30% increase to the value obtained from soil cover complex. Finally, the design flood hydrograph was consturcted by employing unit hydrograph technique to the dimensionless mass curve. Also a stepwise multiple regression was performed to find the relationship between runoff and API, evapotranspiration rate, 5 days antecedentprecipitation and daily temperature.

• Journal of Korean Society for Geospatial Information Science
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• v.8 no.2 s.16
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• pp.11-22
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• 2000

It needs to extract the accurate topological characteristics and hydrological parameters of watershed in order to manage water resource efficiently. But, these data are processed yet by manual wok and simple operation in hydrologic fields. In this paper, we presented algorithm that could extract topological characteristics and hydrological parameters over watershed using GSIS and it gives the saving of data processing tin and the confidency of data. We presented coupling method between GSIS and hydrologic model by using extracted parameters into the input parameter of HEC-HMS hydrologic model. The extraction procedure of topological characteristics and hydrological parameters is as below. First, watershed and stream are extracted by DEM and curve unmber is extracted throughout the overlay of landuse map and soil map. Also, we extracted surface parameters like the length of the longest flow path and the slope of the longest flow path by Grid computation into watershed and stream. And we gave the method that could extract hydrologic parameters like Muskingum K and sub-basin lag tin by executing computation into surface parameters and average Sn curve number being extracted.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.243-246
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• 2005

Alismatis Rhizoma is an oriental medicine originated from the rhizome of Alisma orientale or Alisma plangtago-aquatica var. orientale (Alismataceae). As an standard compound of this plant, alisol B 23-acetate was isolated from the dichloromethane fraction of Alisma orientale and identified by the spectroscopic evidences. A Quantitative analysis of alisol B 23-acetate using HPLC method showed that the average content was 0.47$\pm$0.11% in 33 samples throughout the various regions of Korea.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.934-940
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• 2010

The reduction of [$Os_3(CO)_{11}P(OMe)_3$] and subsequent ionic coupling of the reduced species with $[Ru({\eta}^5-C_5H_5)(CH_3CN)_3]^+$ resulted in the formation of [$Os_3(CO)_{11}P(OMe)_3(Ru({\eta}^5-C_5H_5))_2$] which can be converted to spiked tetrahedral cluster, [$HOs_3(CO)_{11}P(OMe)_3Ru_2({\eta}^5-C_5H_5)(C_5H_4)$] via the intramolecular hydrogen transfer. Due to the unavailability of a suitable single crystal, the PW91/SDD and LDA/SDD density functional methods were used to predict possible structures and the available spectroscopic information (IR, NMR) of [$Os_3(CO)_{11}P(OMe)_3(Ru({\eta}^5-C_5H_5))_2$]. The most probable geometry found by constrained search is the isomer (a2) in which the phosphite, $P(OMe)_3$, occupies an axial position on one of the two osmium atoms that is edge bridged by the $Ru(CO)_2({\eta}^5-C_5H_5)$ unit. By using the most probably geometry, the predicted infrared frequencies and $^1H$, $^{13}C$ and $^{31}P$ NMR chemical shifts of the compound are in the same range as the experimental values. For this type of complex, the LDA/SDD method is appropriate for IR predictions whereas the OPBE/IGLO-II method is appropriate for NMR predictions. The activation energy and reaction energy of the intramolecular hydrogen transfer coupled with the structural change of the transition metal framework were estimated at the PW91/SDD level to be 110.32 and -0.14 kcal/mol respectively.

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.882-890
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• 2000

Ab initio calculations are carried out on protonation equilibria of 5-memberedheteroaromatic aldehydes (5MHAs;heteroatom Y = NH, O, PH,and S and substituentZ = NH2, OCH3, SCH3, CH3, H, Cl, CHO, CN,NO2) at the $MP2}6-31G*$ level. Naturalbond orbital (NBO) analyses show that the optimal localized natural Lewis structures of the protonated aldehydes,(P), are ortho (C3) protonated (for Y = O, PH and S) and N-pro-tonated (for Y = NH) forms in contrast to the standard structural Lewis formula for aldehydes, (R). The delo-calizability of ${\pilone}-pairon$ the heteroatom $(n{\pi}(Y))$ is in the order Y = NH > O > S > PH. The transmission efficiency of (Z) substituent effects to the carbonyl moiety run parallel to the delocalizability of $n{\pi}(Y)$ for R,but is dominantly influenced by the cationic charge on $C{\alpha}(C{\alpha}+)$ for P, which is in the reverse order of thede-localizability of $n{\pi}(Y).$ The Hammett ${\rho}values$ for variation of Z in the protonation are determined by the dif-ference in the transmission efficiencies between Pand R stateat simple interpretation of their magnitude is not warranted. However,the magnitude of the gas-phase ${\rho}z+$ values decreases as the level ofcomputation is raised from RHF/3-21G* to RHF/6-31G* and to $MP2}6-31G*$ but increases again at the MP4SDQ/6-31G* level. Further decrease occurs when solvent effect (water) is accounted for by the SCRF method. Comparison of the SCRF ${\rho}z+values$ with those determined in the aqueous acid solution for Y = S and CHCH shows inadequacy of accounting for the solvent effects on the ${\rho}values$ by a continuum model. It is noteworthy that semiempirical calculations, especially theAM1 method, give even lower magnitude of the gas-phase ${\rho}values.