• Journal of the Korean Chemical Society
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• v.42 no.3
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• pp.266-276
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• 1998

Cholesterol supersaturation in bile, which causes gallstone formation, is the result of low bile acid secretion or high cholesterol secretion. The quantitative analysis of cholesterol, bile acids and sterols which are precursors of cholesterol have been used to examine the changes in bile component. We described a simple, sensitive and reproducible method for simultaneous determination of cholesterol, five bile acids and seven sterols in human bile juices and gallstones by capillary column gas chromatography-mass spectrometry (GC/MS). Clinical samples were hydrolyzed by alcoholic KOH, extracted twice (pH 14 and 1) and derivatized to trimethylsilyl (TMS) ether with $MSTFA/NH_4I$ (N-methyl-N-trimethylsilyltrifluoroacetamide/ammonium iodide) mixture in order to be detected on the GC/MS. The good quality control data were obtained through within-a-day and day-to-day test (RSD values were 1.72-13.79, 0.68-14.10, respectively) and the recovery range of them was 73.56-96. 95 Using this method, biliary and gallstone compositions in the patients with intrahepatic stones were analyzed. The amounts and its relative distribution of cholesterol, bile acids and sterols showed different pattern in bile juices and gallstones.

• Journal of Pharmacopuncture
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• v.17 no.4
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• pp.36-49
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• 2014

Objectives: Quercetin and curcuminoids are important bioactive compounds found in many herbs. Previously reported high performance liquid chromatography ultraviolet (HPLC-UV) methods for the detection of quercetin and curcuminoids have several disadvantages, including unsatisfactory separation times and lack of validation according the standard guidelines of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use. Methods: A rapid, specific, reversed phase, HPLC-UV method with an isocratic elution of acetonitrile and 2% v/v acetic acid (40% : 60% v/v) (pH 2.6) at a flow rate of 1.3 mL/minutes, a column temperature of $35^{\circ}C$, and ultraviolet (UV) detection at 370 nm was developed. The method was validated and applied to the quantification of different types of market available Chinese medicine extracts, pills and tablets. Results: The method allowed simultaneous determination of quercetin, bisdemethoxycurcumin, demethoxycurcumin and curcumin in the concentration ranges of $0.00488-200{\mu}g/mL$, $0.625-320{\mu}g/mL$, $0.07813-320{\mu}g/mL$ and $0.03906-320{\mu}g/mL$, respectively. The limits of detection and quantification, respectively, were 0.00488 and $0.03906{\mu}g/mL$ for quercetin, 0.62500 and $2.50000{\mu}g/mL$ for bisdemethoxycurcumin, 0.07813 and $0.31250{\mu}g/mL$ for demethoxycurcumin, and 0.03906 and $0.07813{\mu}g/mL$ for curcumin. The percent relative intra day standard deviation (% RSD) values were $0.432-0.806{\mu}g/mL$, $0.576-0.723{\mu}g/mL$, $0.635-0.752{\mu}g/mL$ and $0.655-0.732{\mu}g/mL$ for quercetin, bisdemethoxycurcumin, demethoxycurcumin and curcumin, respectively, and those for intra day precision were $0.323-0.968{\mu}g/mL$, $0.805-0.854{\mu}g/mL$, $0.078-0.844{\mu}g/mL$ and $0.275-0.829{\mu}g/mL$, respectively. The intra day accuracies were 99.589%-100.821%, 98.588%-101.084%, 9.289%-100.88%, and 98.292%-101.022% for quercetin, bisdemethoxycurcumin, demethoxycurcumin and curcumin, respectively, and the inter day accuracy were 99.665%-103.06%, 97.669%-103.513%, 99.569%-103.617%, and 97.929%-103.606%, respectively. Conclusion: The method was found to be simple, accurate and precise and is recommended for routine quality control analysis of commercial Chinese medicine products containing the flour flavonoids as their principle components in the extracts.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.461-468
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• 2015

Simultanious quantitative determination of Cetyltrimetyl ammonium chloride(CTM), Stearamidopropyl dimetylamine(SAP), Behentriammonium chloride(BHT), Dihexadeyldimethyl ammonium chloride(DHDDM) was carried out by reversed phase HPLC. The 0.2% TFA/Methanol was used for the mobile phase of gradient conditions. An Alltech $C_{18}$($250mm{\times}4.6mm$ i.d., $5{\mu}m$)and the selected ELSD detector was applied. The analysis results of HPLC showed good linearity with correlation coefficient of $r^2=0.997$ in the rage of $130{\sim}1980.5{\mu}g/mL$ and detection limit.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.1956-1964
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• 2014

To provide the scientific corroboration of the traditional uses of Akebia quinata (Thunb.) Decne., a detailed analytical examination of A. quinata stems was carried out using a reversed-phase high performance liquid chromatography (RP-HPLC) method coupled to photodiode array detector (PDA) for the simultaneous determination of four phenolic substances; cuneataside D (1), 2-(3,4-dihydroxyphenyl)ethyl-O-${\beta}$-D-glucopyranoside (2), 3-caffeoylquinic acid (3) and calceolarioside B (4). Particular attention was focused on the main compound, 3-caffeoylquinic acid (3), which has a range of biological functions. In addition, 2-(3,4-dihydroxyphenyl)ethyl-O-${\beta}$-D-glucopyranoside (2) was considered as a discernible marker of A. quinata from its easy confuse plants. The contents of compounds 2 and 3 ranged from 0.72 to 2.68 mg/g and from 1.66 to 5.64 mg/g, respectively. The validation data indicated that this HPLC/PDA assay was used successfully to quantify the four phenolic compounds in A. quinata from different locations using relatively simple conditions and procedures. The pattern-recognition analysis data from 53 samples classified them into two groups, allowing discrimination between A. quinata and comparable herbs. The results suggest that the established HPLC/PDA method is suitable for quantitation and pattern-recognition analyses for a quality evaluation of this medicinal herb.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.4
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• pp.389-400
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• 2008

As the wireless network technologies and the capability of the mobile terminals are evolving, advanced peer to peer applications for mobile users are attracting interests. In this paper, we propose the mobile P2P communication platform(MPCP) which provides transparency to the wireless network technologies and solutions to the limited resources of the mobile terminals. MPCP classifies the connection into two levels: a virtual channel and a session. A virtual channel is the network layer connection between the terminals whereas a session is the application layer connection. MPCP classifies the sessions into four types and applies different scheduling priority and data processing policies such as segmentation and reassembly. It selects proper wireless network technologies depending on the distance between the communication endpoints. To acquire dynamically changed access address, we harness the Session Initiation Protocol. We implemented MPCP on embedded Linux simulator and utilized the implementation in mobile P2P service development. For the quantitative analysis, we compared the performance of MPCP with that of ftp. Regardless of the number of simultaneous sessions, MPCP maintains the relative performance.

• Composites Research
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• v.16 no.3
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• pp.58-67
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• 2003

To perform the realtime strain and fracture monitoring of the smart composite structures, two optical fiber sensor systems are proposed. The two types of the coherent sources were used for fracture signal detection - EDFA with FBG and EDFA with Fabry-Perot filter. These sources were coupled to EFPI sensors imbedded in composite specimens. To understand the characteristics of matrix crack signals, at first, we performed tensile tests using surface attached PZT sensors by changing the thickness and width of the specimens. This paper describes the implementation of time-frequency analysis such as short time Fourier transform (STFT) and wavelet transform (WT) for the quantitative evaluation of fracture signals. The experimental result shows the distinctive signal features in frequency domain due to the different specimen shapes. And, from the test of tensile load monitoring using optical fiber sensor systems, measured strain agreed with the value of electric strain gage and the fracture detection system could detect the moment of damage with high sensitivity to recognize the onset of micro-crack fracture signal.

• Korean Journal of Remote Sensing
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• v.27 no.4
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• pp.403-410
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• 2011

Consistent observation with high temporal and spatial resolution is required for an efficient monitoring of coastal environments. Remote monitoring system installed on the ground is capable of simultaneous observation of wide coastal area and consistent observation with high frequency, which a small number of in-situ measurements cannot manage. This paper studies two typical ground based coastal monitoring system, marine radar and camera system. Marine radar can produce time series of frequency spectrum by integrating wave number spectrum calculated from spatial and temporal variation of waves in the radar image. The time averaged radar images of waves can analyze wave breaking zone, rip currents and location of littoral bars. Camera system can observe temporal variation of foam generation originated from coastal contamination as well as shoreline changes. By extracting the part of foams from rectified images, quantitative analysis of temporal foam variation can be done. By using the two above systems of different characteristics, synergetic benefit can be achieved.

• Analytical Science and Technology
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• v.12 no.4
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• pp.265-272
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• 1999

A simultaneous profile analysis of 19 environmental estrogens, which act like estrogen and may effect the endocrine system by binding to hormone receptors or influencing cell signaling pathways, was attempted. The present method was based on the selected ion monitoring (SIM) mode of gas chromatography/mass spectrometry (GC/MS). It involves solid-liquid extraction, enzyme hydrolysis, liquid-liquid extraction and quantitative conversion into trimethylsilyl (TMS)-ether derivatives. Analytical recovery range was 47.6 ~ 99.5% and the RSD values of within-a-day and day-to-day test were 0.66 ~ 9.33%, 1.66 ~ 16.14%, respectively. The Korean reference values for the evaluation of environmental estrogen effects were established by this method.

• Analytical Science and Technology
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• v.8 no.4
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• pp.759-770
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• 1995

By extensive studies with the quantitative status of the mineral constituents of thousands of water samples, it was found that almost in all natural waters irrespective of the surface or sub-surface sources, minimum 99.5% of the total amount of the cationic constituents are generally the contributions of 3 commonly present parameters viz. Ca, Mg and Na and that of the anionic species are same and contributed by $HCO_3$, Cl and $SO_4$ only. In the field of water works, all these major mineral substances are conventionally measured as their individual ions. But till now, no reliable and generalised methods or rules have been developed for the determination of the exact kinds of the individual salt components and their amounts from these ionic constituents normally present in water. As salt content, only the TDS (Total Dissolved Solids) parameter is frequently measured by evaporation of the water sample. But TDS can tell nothing about the kinds and amounts of the individual salts present in it. Considering the analytical importance of the estimation of the mineral substances as their individual salts, some generalised mathematical models have been developed by this research which are based on the 'hypothetical order of chemical combinations' as may occur among the ionic constituents. With the help of these models, one can easily assume the most probable salts with approximate quantities derived from the ionic constituents. In addition, approximate amount of Na content can also be estimated mathematically with simultaneous verification of the correctness of the water analysis results. The models are stated in this paper with practical illustrations and descriptions of the method of applications.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.140-145
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• 2009

All organisms are being exposed to harmful factors present in the environmental. The combined action of various factors is a distinguishing feature of modern life. An interaction between two chemicals is considered as synergistic when the effect produced is greater than the sum of the two single responses. The biological effects due to the combined action of ionizing radiation with the other factor are hard to estimate and predict in advance. In the current study, we investigated the synergistic effects between ionizing and $HgCl_2$ using fish hepatoma cells (PLHC-1 cells). The results showed a dramatic decrease of cell viability after simultaneous treatment of PLHC-1 cells with ionizing radiation and $HgCl_2$. Neiither of the two had any cytotoxic effect when treated alone. The cytotoxicity of ionizing radiation was enhanced in the presence of $HgCl_2$. The synergistic effects were observed after exposure of the PLHC-1 cells to ionizing radiation combined with $HgCl_2$. The synergistic interaction was due to an increase of irreversibly damaged cells after the combined exposure. Analysis of the extent of synergistic interaction enables to make quantitative estimation of irreversibly damaged cells after the combined exposure. The present study suggests that PLHC-1 cells can serve as rapid screening tools for detecting the toxicity of harmful factors.