• Journal of Pharmaceutical Investigation
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• v.39 no.3
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• pp.177-183
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• 2009

A rapid and sensitive reversed-phase high performance liquid chromatography (HPLC) method was developed for the determination of piroxicam in the rabbit plasma. After a treatment of plasma sample by liquid-liquid extraction, the drug was analyzed on an HPLC system with ultraviolet detection at 330 nm. HPLC was carried out using reversed-phase isocratic elution with a C18 column, a mobile phase of a mixture of acetonitril, doubly deionized water and acetic acid 43.74:56.00:0.26 v/v%) at a flow rate of 1.1 mL/min. The chromatograms showed good resolution and sensitivity and no interference of plasma. The calibration curve for the drug in plasma sample was linear over the concentration range of 0.01-2.0 ${\mu}$g/mL. The intra- and inter-day assay accuracies of this method ranged from 86.82% to 108.33% of normal values and the precision did not exceed 13% of relative standard deviation. The plasma concentration of piroxicam decreased to below the quantifiable limit at 12 hr after the i.v. bolus administration to rabbits following dose of 0.375 mg/kg yielding a apparen t plasma half life of 1.38 hr. The transdermal route prolongs plasma levels of piroxicam. The bioavailability, calculated from the dose-adjusted ratio of the $AUC_{transdermal}$ to the $AUC_{i.v.}$, was 7.44%. The plasma concentration of piroxicam was detected by 48 hr after the transdermal administration of patch at a dose of 32 mg/kg. This method was suitable for cutaneous absorption studies of piroxicam in the rabbit after transdermal administration of different types of dosages of the drug.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.34.1-34.1
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• 2013

Interstellar ices (e.g., $H_2O$, $CO_2$, and CO ices) are formed on the surface of dust grains in dense molecular clouds. In a near-infrared spectrum, we can observe deep absorption features particularly due to $H_2O$ ice at $3.05{\mu}m$ and $CO_2$ ice at $4.27{\mu}m$. These interstellar ices have many pieces of information on the interstellar environment. Among various ices, $CO_2$ ice is one of the most important ones as a probe of the interstellar environment. That is because $CO_2$ ice is a secondary product unlike $H_2O$ and CO ices which are primarily formed on dust grains. Past studies for $CO_2$ ice in nearby galaxies were performed only for the galactic center in a few galaxies. In order to utilize the information from $CO_2$ ice effectively, it is valuable to perform mapping observations of ices on a galactic scale. With AKARI, we obtain the spatially-resolved near-infrared ($2.5-5.0{\mu}m$) spectra for the central ~1 kpc region of the nearby starburst galaxy M 82. These spectra clearly show the absorption features due to interstellar $H_2O$ and $CO_2$ ices, and we created their column density maps. As a result, we find that the spatial distribution of $H_2O$ ice is significantly different from that of $CO_2$ ice; $H_2O$ ice is widely distributed, while $CO_2$ ice is concentrated near the galactic center. Our result for the first time reveals spatial variations in $CO_2/H_2O$ ice abundance ratio on a galactic scale, suggesting that the ice-forming interstellar environment changes within a galaxy. In this presentation, we discuss the cause of the variations in the ice abundance ratio.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.4
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• pp.407-413
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• 2006

Artificial aggregates made by coal fly ash that is classified as an industrial by-product was tested to oxidize hydrogen sulfide under various testing conditions. For the determination of optimum condition for converting coal fly ash to aggregates, specimens were prepared by varying ratio of fly ash, cement, water content, and foaming agent. These specimens were tested to determine specific gravity, water absorption, and compressive strength. Specimens, which were used for the removal of hydrogen sulfide, were selected based on the measured specific gravity, water absorption, and compressive strength. Tests for hydrogen sulfide removal were performed via batch and column tests. Under the testing conditions used in this study, removal rates of hydrogen sulfide were linearly proportional to amounts of coal fly ash, and further increased when water was added.

• Microbiology and Biotechnology Letters
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• v.1 no.1
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• pp.13-18
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• 1973

For the production of Nucleic acid derivatives by microorganisms, adenineless mutants were induced from Bacillus subtilis with the mutagens, ultraviolet rays and diethylsulfate. And total strains of 62 adenineless mutants were isolated. These mutants were found to have an ability of accumulating u. v. absorbing substances in the culture broth. They were analyzed to be hypoxanthine, uracil, and other unknown compound by means of two dimensional thin layer chromatography, u. v. absorption spectra, and I. R. absorption spectrum. Mutant BS-137 was screened out to accumulate hypoxanthine, which was isolated from the culture broth through activated carbon column and recrystallize from cold water. The effect of the medium compositions on hypoxanthine accumulation were examined for the mutant BS-137. Glucose appeared to be the best carbon source, but molasses could be substitute for it, NaNO$_3$ and yeast extract were especially good sources of nitrogen.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.409-414
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• 1998

To examine the detectability of the aerosol and/or Yellow dust from China crossing over the Yellow sea, three works carried out as follows , Firstly, a comparison was made of the visible(VIS), water vapor(WV), and Infrared(IR) images of the GMS-5 and NOAA/AVHRR on the cases of yellow sand event over Korea. Secondly, the spectral radiance and reflectance(%) was observed during the yellow sand phenomena on April, 1998 in Seoul using the GER-2600 spectroradiometer, which observed the reflected radiance from 350 to 2500 nm in the atmosphere. We selected the optimum wavelength for detecting of the yellow sand from this observation, considering the effects of atmospheric absorption. Finally, the atmospheric radiance emerging from the LOWTRAN-7 radiative transfer model was simulated with and without yellow sand, where we used the estimated aerosol column optical depth ($\tau$ 673 nm) in the Meteorological Research Institute and the d'Almeida's statistical atmospheric aerosol radiative characteristics. The image analysis showed that it was very difficult to detect the yellow sand region only by the image processing because the albedo characteristics of the sand vary irregularly according to the density, size, components and depth of the yellow sand clouds. We found that the 670-680 nm band was useful to simulate aerosol characteristics considering the absorption band from the radiance observation. We are now processing the simulation of atmospheric radiance distribution in the range of 400-900 nm. The purpose of this study is to present the preliminary results of the aerosol and/or Yellow dust detectability using the Ocean Scanning Multispectral Imager(OSMI), which will be mounted on KOMPSAT-1 as the ocean color monitoring sensor with the range of 400-900 nm wavelength.

• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.16-22
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• 2008

on-line system for preconcentration and separation of lead(II) is presented. The method is based on the complex formation of Pb(II) with adsorbed Methyl thymol blue on activated carbon. The conditions of preparing the solid phase reagent and of quantitative recovery of Pb(II) from diluted solutions, such as acidity of aqueous phase, solid phase capacity, and flow variables were studied as well as effect of potential interfering ions. After preconcentration step, the metal ions are eluted automatically by 5 ml of 0.5 M HNO3 solution and the lead ions content was determined by flame atomic absorption spectrometry. Under the optimum conditions, the lead ions in aqueous samples were separated and preconcentrated about 1000-fold by the column. The detection limit was 0.001 g mL-1. Lead has been determined in river and tap water samples, with recovery of 98 to 102%.

• Plant Journal
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• v.8 no.4
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• pp.40-44
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• 2012

The pre-treatment of natural gas to remove $H_2S$ and $CO_2$ before liquefaction in natural gas processing is required, and amine-based absorption processes are widely used in gas processing. The current study aims to model amine-based absorption process and to find cost-effective design through systematic analysis of energy systems, together with column design. Different design options for absorber and stripper are investigated in a holistic manner, and heat integration technique has been applied to investigate how design of columns is interacted with energy efficiency for the pre-treatment process considered. Case study has been presented to demonstrate the applicability of heat integration method for improving energy efficiency in practice.

• Geomechanics and Engineering
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• v.36 no.3
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• pp.303-316
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• 2024

Seismic records are composed of mainshock and a series of aftershocks which often result in the incremental damage to underground structures and bring great challenges to the rescue of post-disaster and the repair of post-earthquake. In this paper, the repetition method was used to construct the mainshock-aftershocks sequence which was used as the input ground motion for the analysis of dynamic time history. Based on the Daikai station, the two-dimensional finite element model of soil-station was established to explore the failure process of station under different seismic precautionary intensities, and the concept of incremental damage of station was introduced to quantitatively analyze the damage condition of structure under the action of mainshock and two aftershocks. An arc rubber bearing was proposed for the shock absorption. With the arc rubber bearing, the mode of the traditional column end connection was changed from "fixed connection" to "hinged joint", and the ductility of the structure was significantly improved. The results show that the damage condition of the subway station is closely related to the magnitude of the mainshock. When the magnitude of the mainshock is low, the incremental damage to the structure caused by the subsequent aftershocks is little. When the magnitude of the mainshock is high, the subsequent aftershocks will cause serious incremental damage to the structure, and may even lead to the collapse of the station. The arc rubber bearing can reduce the damage to the station. The results can offer a reference for the seismic design of subway stations under the action of mainshock-aftershocks.

• Korean Journal of Remote Sensing
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• v.35 no.6_3
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• pp.1173-1185
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• 2019

We, for the first time, retrieved sulfur dioxide (SO₂) vertical column density (VCD) in industrial and volcanic areas from TROPOspheric Monitoring Instrument (TROPOMI) using the Principle component analysis(PCA) algorithm. Furthermore, SO₂ VCDs retrieved by the PCA algorithm from TROPOMI raw data were compared with those retrieved by the Differential Optical Absorption Spectroscopy (DOAS) algorithm (TROPOMI Level 2 SO₂ product). In East Asia, where large amounts of SO₂ are released to the surface due to anthropogenic source such as fossil fuels, the mean value of SO₂ VCD retrieved by the PCA (DOAS) algorithm was shown to be 0.05 DU (-0.02 DU). The correlation between SO₂ VCD retrieved by the PCA algorithm and those retrieved by the DOAS algorithm were shown to be low (slope = 0.64; correlation coefficient (R) = 0.51) for cloudy condition. However, with cloud fraction of less than 0.5, the slope and correlation coefficient between the two outputs were increased to 0.68 and 0.61, respectively. It means that the SO₂ retrieval sensitivity to surface is reduced when the cloud fraction is high in both algorithms. Furthermore, the correlation between volcanic SO₂ VCD retrieved by the PCA algorithm and those retrieved by the DOAS algorithm is shown to be high (R = 0.90) for cloudy condition. This good agreement between both data sets for volcanic SO₂ is thought to be due to the higher accuracy of the satellite-based SO₂ VCD retrieval for SO₂ which is mainly distributed in the upper troposphere or lower stratosphere in volcanic region.

• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.282-287
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• 2001

This study was carried out to investigate the difference of ginsenoside compositions in crude ginseng saponins prepared by five different methods including three new methods. Two known methods are hot methanol(MeOH) extraction/n-butanol(n-BuOH) fractionation and hot MeOH extraction/Diaion HP-20 adsorption/MeOH elution. Three new methods are hot MeOH extraction/cation AG 50W $absorption/H_2O$ elution/n-BuOH extraction, cool MeOH extraction/Diaion HP-20 adsorption/MeOH elution and direct extraction with ethyl acetate(EtOAc)/n-BuOH. Analysis of ginsenoside composition in the crude saponins by conventional HPLC/RI(Refractive Index) did not show great difference between methods except EtOAc/n-BuOH method. However, HPLC/ELSD (evaporative light scattering detector) employing gradient mobile phase afforded fine resolution of ginsenoside Rf, $Rg_1$ and $Rh_1$, and great difference of ginsenoside compositions between methods. LC/MS revealed that large amount of prosapogenins were produced during the pass through the cation exchange (AG 50W) column being strongly acidic. Six major ginsenosides such as $Rb_1,w;Rb_2,$ Rc, Rd, Re and $Rg_1$, 5 prosapogenins and one chikusetsusaponin were identified by LC/MS. A newly established HPLC method employing ODS column and gradient mobile phase of $KH_2PO_4/CH_3CN$ revealed that malonyl ginsenosides were detected only in the crude saponin obtained from cool MeOH extraction.