• Geophysics and Geophysical Exploration
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• v.10 no.1
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• pp.60-68
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• 2007

Conventional analysis of spectral induced polarization (SIP) data consists of measuring impedances over a range of frequencies, followed by spectral analysis to estimate spectral parameters. For the quantitative and accurate estimation of subsurface SIP parameter distribution, however, a sophisticated and stable inversion technique is required. In this study, we have developed a two-step inversion approach to obtain the two-dimensional distribution of SIP parameters. In the first inversion step, all the SIP data measured over a range of frequencies are simultaneously inverted, adopting cross regularisation of model complex resistivities at each frequency. The cross regularisation makes it possible to enhance the noise characteristics of the inversion by imposing a strong assumption, that complex resistivities should show similar characteristics over a range of frequencies. In numerical experiments, we could verify that our inversion approach successfully reduced inversion artefacts. As a second step, we have also developed an inversion algorithm to obtain SIP parameters based on the Cole-Cole model, in which frequency-dependent complex resistivities from the first step are inverted to obtain a two-dimensional distribution of SIP parameters. In numerical tests, the SIP parameter images showed a fairly good match with the exact model, which suggests that SIP imaging can provide a very useful subsurface image to complement resistivity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1363-1368
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• 2008

The extraction and quantitative analysis conditions for astaxanthin from Haematococcus pluvialis, and the structural characteristics of H. pluvialis extract, H. pluvialis hydrolysate and synthetic astaxanthin were investigated using UV/visible and FT-IR spectrometers. Astaxanthin was dissolved in methanol, and then treated to enhance the solubility by sonication for 45 min. With sonication pretreatment, the solubility of astaxanthin increased up to 1.5 times compared to that without sonication. The extracts were hydrolyzed by cholesterol esterase for the analysis of H. pluvialis extract containing astaxanthin ester. A HPLC method using reverse phase C18 column with methanol-water (95:5, v/v) as mobile phase was developed to analyze astaxanthin. After hydrolysis, the absorption spectrum of H. pluvialis hydrolysat was changed to similar pattern to synthetic astaxanthin, confirming the extraction and analysis condition of astaxanthin from H. pluvialis.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.453-459
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• 2006

D-tryptophan and N-CBZ-D-phenylalanine were separated using ionic liquid as additives for the mobile phase in high performance liquid chromatography (HPLC). The ionic liquid of 1-butyl-3- methylimidazolium tetrafluoroborate (${[BMIm]}^+{[BF_4]}^-$) was used. Mobile phases were 65％, 70％, and 80％ methanol in water with addition of different concentrations (0.5, 1.0, 1.5, 2.0, 4.0, 6.0, 8.0, 10.0, 12.0, and 15.0 mmol/L) of the ionic liquid. The experiments were performed on stainless steel column, $3.9{\times}300mm$ i.d., packed with $15{\mu}m$ octadecyl-bonded silica gel at laboratory.The retention factor of D-tryptophan was not negligibly changed while that of N-CBZ-D-phenylalanine was decreased. The resolution between the two components were affected by the contents of methanol and ionic liquid in the mobile phase. With the small content of methanol and the high concentration of ionic liquid, the resolution was improved.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.37-45
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• 1975

The present study was ,conducted to evaluate the effects of condensed phosphates on the refeezing damage of Alaska pollack muscle. The fillets were dipped in such solution as 5 and $10\%$ sodium polyphosphate, 1 and $5\%$ mixture of sodium polyphosphate and sodium pyrophosphate (1:1, w/w) for 1 and 5 minutes, respectively, before refreezing. And fillets were frozen at $27^{\circ}C\~28^{\circ}C$ and stored for 15 days at $-18^{\circ}\~-20^{\circ}$. The degree of denaturation was estimated by determining amounts of drip relased, content of total solids, nitrogen, and DNA in the drip an cooking-weight-loss. Phosphorus absorbed in the muscle was also determined. Phosphorus absorbed in the fillets treated with loft solution of sodium polyphosphate for 5 minutes amounted to 101 mg/100g muscle as $P_2O_5$. The absorption was dependent on tile concentration of treating solution rather than on the dipping time. The increase of phosphorus absorption seemed to affect to reduction of drip. Among the treating conditions, $10\%$, 5 minutes and $10\%$ 1 minute with sodium polyphosphate appeared most effective ones on drip reduction. The effect of $5\%$, minutes with the mixture of sodium polyphosphate and sodium pyrophosphate did not show so benefitable effect in refrozen fillets. As a tendency total solids, nitrogen, and DNA in tile drip varied proportionally to the amount of drip released. And the content of DNA was lower than the amount. Treatment, at higher the concentration and longer the dipping time, resulted in the lower cooking-weight-loss and the better quality on organoleptic test of thawed fillets.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.211-215
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• 2005

Three curcuminoids [curcumin (CUR), demethoxycurcumin(DEM), bisdemethoxycurcu in (BIS)] are major yellow pigments in turmleric (Curcuma longa L.) root. Contents of curcuminoids in turmeric roots collected from 6 locations were analyzed using, high performance liquid chromatography (HPLC) equipped with reversed-phase column, an UV-Vis detector at 420nm, and eluted with a mixture of acetonitrile: $0.1\%$ acetic acid in water (50 : 50, v/v) as mobile phase. The stability of curcuminoid pigments in $80\%$ methanol extract solution were investigated during storage in a freezer at $-20^{\circ}C$, room temperature in the dark, and light condition. Calibration curves for the determination of curcuminoids were made with significant linearity $(r^2=0.999**)$. Average content of total curcuminoids was 171.5 mg/g, with 91.6 mg/g of CUR, 56.9 mg/g of DEM, and 23.0 mg/g of BIS. Amount of curcuminoids during storage in a freezer was almost not changed while those in room temperature wert reduced and rapid degradation appeared after 60 days. Within 90 days, about $50\%$ curcuminoid decreased in the dark and about $70\%$ in the light condition, indicating the decomposition of curcuminoid pigments followed under light and heat.

• Journal of the Korean Applied Science and Technology
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• v.14 no.1
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• pp.61-76
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• 1997

Triacylglycerols of the seeds of Ginkgo biloba have been resolved by high-performace liquid chromatography(HPLC} in the silver-ion and reverse-phase modes. The fatty acids were identified by a combination of capillary gas chromatography and gas-chromatography /mass spectrometry as the methyl and /or picolinyl ester. The main components are $C_{18:2{\omega}6}$(39.0mol%), $C_{18:1{\omega}7}$(asclepic acid 21.5mol%), and $C_{18:1{\omega}9}$(oleic acid, 13.8mol%). Considerable amounts of unusual acid such as $C_{20:3{\Delta}^{5,11,14}$ (5.7mol%), $C_{18:2{\Delta}^{5,9}$(2.8mol%), and $C_{18:3}{\Delta}^{5,9,12}$(1.6mol%), were checked. In addition, an anteiso-branched fatty acid, 14-methylhexadecanoic acid, was also present as a minor component(0.9 mol%). The triacylglycerols were separated into 17 fractions by reverse-phase HPLC, and the fractionation was achieved according to the partition numnber(PN) in which a ${\Delta}^5$-non methylene interrupted double bond($^5$-NMDB) showed different behaviour from a methylene interrupted double bond in a molecule with a given cahinlength. Silver-ion HPLC exhibited excellent resolution in which fractions(23 fractions) were resolved on the basis of the number and configuration of double bonds. In this instance, the strength of interaction of a ${\Delta}^5$-NMDB system with silver ions seemed to be weaker than a methylene interrupted double bond system. The principal triacylglycerol species are as follows ; $(C_{18:2{\omega}6)2}/C_{18:1{\omega}7}$, $C_{18:1{\omega}9}/C_{18:1{\omega}7}/C_{18:2{\omega}6}$, $(C_{18:1{\omega}7)2}/C_{18:2{\omega}6}$, $C_{16:1{\omega}7}/C_{18:1{\omega}9}/C_{20:3}{\Delta}^{5,11,14}$, $C_{16:1{\omega}7}/C_{18:1{\omega}7}/C_{20:3}{\Delta}^{5,11,14}$, $C_{18:1{\omega}9}/C_{18:1{\omega}7}/C_{18:2{\omega}6}$, $C_{18:1{\omega}9}/C_{18:2}{\Delta}^{5,5}/C_{20:3}{\Delta}^{5,11,14}$, $(C_{18:1{\omega}7)2}/C_{18:2{\omega}6}$ and $(C_{18:1{\omega}9)2}/C_{18:2{\omega}6}$, while simple triacylglycerols without $C_{18:2{\omega}6})_3$ were not present. Stereospecific analysis showed that fatty acids with ${\Delta}^5$-NMDB system and saturated chains were predominantly located at the site of sn-3 carbon of glycerol backbones. It is evident that there is asymmetry in the distribution of fatty acids in the TG molecules of Ginkgo nut oils.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.3
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• pp.198-204
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• 2000

In order to utilize by-products which would normally be discarded in marine processing plants, cod teiset protein was hydrolyzed and antioxidative actiTity of the hydrolysate was investigated. AntioxidatiTe peptide was isolated using ultrafiltration membrane, ion-exchange chromatography on a SP-Sephadex C-25 column, gel filtration on a Sephadex G-15 column, high performance liquid chromatography on an ODS column, and capillary electrophoresis chromatography. Antioxidative activities of the cod teiset hydrolysate were compared with ${\alpha}-tocopherol$, one of the commercial antioxidant. The hydrolysate passed through a membrane with molecular weight cut-off (MWCO) 1 kDa was shown the strongest antioxidative activity, and the activity was higher $10{\%}$ as compared with ${\alpha}-tocopherol$. In addition, the peptide isolated by ion-exchange chromatography, gel filtration, and HPLC, respectively, was higher $53{\%}$ as compared with ${\alpha}-tocopherol$, and the amino acid sequence was Ser-Asn-Pro-Glu-Trp-Ser-Trp-Asn.

• Journal of Korea Water Resources Association
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• v.48 no.1
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• pp.9-21
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• 2015

This study examined pollution level of sediment in Sookchun lake, and studied dredging validity by examining phosphorous release characteristics on surface polluted soil. Total phosphorous, the principal cause of algal blooms, exceeded dredging assessment standards regarding Daechung lake (1.5 mg/g) at all points. Also at all points, total nitrogen exceeded the dredging assessment standard regarding Paldang Lake (1.1 mg/g), but fell short of the standard regarding Daechung lake (3.0 mg/g). Dredging zone was suggested in this study is Chuso water body (WS-6~WS-12) in Sookchun lake. In relation to sediment pollution levels measured at different depths, LOI tended to decrease as it became deeper. The concentrations of T-N varied depending upon the depth as well as points, but no regular pattern was observed. The depth and site did not significantly influence T-P. From the results of phosphorous release tests, it was shown that total phosphorous release flux was calculated to be $7.2{\sim}15.4mg/m^2/d$ for anaerobic condition, $0.5{\sim}2.0mg/m^2/d$ for aerobic condition and $2.0{\sim}4.1mg/m^2/d$ for facultative condition. Release flux and T-P concentration of surface sediments had positive correlation ($R^2$ 0.7871). And The corelation between release flux and DO condition in reactor had strong negative correlation ($R^2$ 0.8824).

• Analytical Science and Technology
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• v.30 no.6
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• pp.348-354
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• 2017

In this study, patterns of proteome expression were monitored and specifically expressed proteins in human milk were detected in collected human milk after 1 week, 3 weeks, and 6 weeks from delivery. A quantitative shotgun proteomic approach was used to identify human milk proteins and reveal their relative expression amounts. For each sample, two independent human milk samples from two mothers were pooled, and then three replicated shotgun proteomic analyses were carried out. Casein, which is a highly abundant protein in human milk, was removed, and then trypsin was treated to produce a digested peptide mixture. The peptides were loaded in the home-made reversed-phase C18 fused-silica capillary column, and then the eluted peptides were analyzed by using a linear ion-trap mass spectrometer. The relative quantitation of proteins was performed by the normalized spectral count method. For each sample, 81-109 non-redundant proteins were identified. The identified proteins consisted of glycoproteins, metabolic enzyme, and chaperon enzymes such as lactoferrin, carboxylic ester hydrolase, and clusterin. The comparative analysis for the 63 proteins, which were reproducibly identified in all three replications, revealed that 25 proteins were statically significant differentially expressed. Among the differentially expressed proteins, Ig lambda-7 chain C region and tenascin drastically decreased with the delivery time.

• 한국해양학회지
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• v.30 no.4
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• pp.341-354
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• 1995

Fluorescence characteristic and amino acids composition of organic matter were determined from extracted seawater samples at eight stations in the East Sea of Korea. Organic compounds have been extracted onto C-18 Sep-Pak cartridges. Three dimensional excitation/emission fluorescence contouring of extracts showed two markedly distinct characterized fluoroscopies representing protein-like biomacromolecule and humic-like geomacromolecule. Protein-like biomacromolecule showing fluorescence maxima at 280 nm/330 nm (excitation/emission) were abundant in the surface mixed layer and then apparently decreased below the thermocline at most stations. It suggests that source of biomacromolecule is comely related with vigorous biological synthetic activity in the surface layer and bacteria decompose its biologically labile components near the thermocline and in the deeper layer. On the other hand, humiliate geomacromolecule showing fluorescence maxima at 330 nm/430 nm (excitation/emission) were low in the surface mixed layer implying photochemical oxidation and then increased below the thermocline at most stations. It suggests that geomacromolecule might be transformed by condensation of bio-refractoryorganic fraction after decomposition of biomacromolecule and particulate organic carbon derived from the surface mixed layer. HPLC measurements of amino acids showed similar composition between seawater and extracted organic macromolecule after hydrolysis. Glycine, serine and alanine were predominant, accounting for more than 50% of total amino acids. Dissolved free amino acids of seawater were more abundant in the surface layer(0.7∼1.8 uM) than the deeper layer (0.2∼0.4 uM). D/L racemic ratio of alanine of extracted organic matter showed lower value in the surface layer than the deeper layer. It suggests that biomacromolecule predominant in the surface layer is relatively young, rapidly recycling and biologically labile.