• Korean Journal of Veterinary Service
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• v.25 no.3
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• pp.221-227
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• 2002

This study was carried out to confirm analytical method of residual macrolides in livestock products by LC/MS. 1. Macrolides were analyzed by LC/MS on XTerra C$\sub$18/ column with 0.1% TFA(trifluoroacetic acid)-methanol in a gradient mode as mobile phase, and that were identified by positive chemical ionization with selective ion monitoring at 50～1000 mass range. 2. Residual macrolides were extracted from tissue with acetonitrile, and the extract is purified with a Sep-pak C$\sub$18/ cartridge, and elute macrolides with 0.1M methanolic ammonium acetate. 3. The procedure confirms the presence of each macrolide at 50$\mu\textrm{g}$/kg in spiked sample.

• Asian Journal of Turfgrass Science
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• v.7 no.1
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• pp.13-18
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• 1993

Much attention has been given recently to solve the environmental contamination in golf courses Changing to culture practice rather than chemical practice that depends on pesticides and fertilizers is a hot issue in golf courses or grasslands. Organic soil conditioners improve soil-plant envirormental conditions rich in physical properties. In this study, measuring systems to evaluate soil conditioning effects were set up for on-site purpose. After establishing the methodology for evaluating soil conditioner effects, 2 kinds of organic conditioners were rested for examination. The systems for the methodology included a set of simulating equipment for field capacity, an impact type soil column compactor, and an infiltration-percolation system. Test results using the systems showed bulk density and infiltration rate of mixed soil were decreased at highter rates of conditioner, but total porocities were increased. Increased porocities were most capillary pore space which has a positive effect on soil water potential. The systems and methodology in this study seem to have an efficiency to measure the effects of soil conditioner on site purpose.

• Analytical Science and Technology
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• v.35 no.2
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• pp.82-91
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• 2022

Grayanotoxin-contaminated honey exhibits toxicity. In this study, a reliable and sensitive liquid-chromatography-tandem-mass-spectrometric method (LC-MS/MS) was developed and validated for the quantitation of grayanotoxin I and grayanotoxin III in honey. The grayanotoxins were extracted from honey via solid phase extraction and separated on a biphenyl column with a mobile phase consisting of 0.5 % acetic acid in water and methanol. Mass spectrometric detection was performed in the multiple-reaction monitoring mode with positive electrospray ionization. The calibration curve covered the range 0.25 to 100 ㎍/g. The intra- and inter-day deviations were less than 10.6 %, and the accuracy was between 94.3 and 114.0 %. The validated method was successfully applied to the determination of grayanotoxins in mad honey from Nepal. The concentrations of grayanotoxin I and grayanotoxin III in 33 out of 60 mad honey samples were 0.75 - 64.86 ㎍/g and 0.25 - 63.99 ㎍/g, respectively. The method established herein would help in preventing and confirming grayanotoxin poisoning.

• Mass Spectrometry Letters
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• v.14 no.4
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• pp.141-146
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• 2023

Liraglutide is a medication prescribed for the management of type 2 diabetes and chronic obesity. A simple, sensitive, and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitative analysis of liraglutide in rat plasma. After a simple protein precipitation step, liraglutide was chromatographically separated using the ACQUITY Premier Peptide BEH C18 Column with mobile phases comprising 50% acetonitrile and 50% methanol, and water with 0.3% FA. Positive ion electrospray ionization in multiple reaction monitoring mode was used to achieve detection. Good linearity was observed in the 5-600 ng/mL concentration range (R² > 0.99). Liraglutide had intra- and inter-day precision values of 2.13%-9.86% and 4.14%-8.36%, respectively. The accuracy ranged from -2.36% to 2.58%. The recovery and matrix effect were within acceptable limits. This selective LC-MS/MS method was used to study the pharmacokinetic properties of liraglutide after subcutaneous administration in rats.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.2
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• pp.168-173
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• 2015

Bangpungtongseong-san(BPTSS, Fangfengtongsheng-san in Chineses) is a traditional herbal formula comprising 18 medicinal herbs. In the present study, we performed the simultaneous analysis for four compounds of BPTSS and examined anti-allergic effects in human keratinocytes and mouse splenocytes. The column for separation of four compounds was used Luna C18 column and maintained at 40℃. The mobile phase for gradient elution consisted of two solvent systems. The analysis was carried out at a flow rate of 1.0 mL/min with PDA detection at 254 and 280 nm. To evaluate production and expression of Th2 chemokines, ELISA and RT-PCR were conducted in tumor necrosis factor (TNF)-α and interferon (IFN)-γ-stimulated HaCaT cells with or without BPTSS or silymarin, a positive control for skin inflammation. To measure Th2 cytokines, primary mouse splenocytes were treated with BPTSS and performed ELISA for interleukin (IL)-4, 5, 13. Calibration curves were acquired with r2>0.9999. The contents of geniposide, liquiritin, baicalin, and glycyrrhizin in BPTSS were 5.06 ㎎/g, 7.33 ㎎/g, 27.56 ㎎/g, and 7.81 ㎎/g, respectively. BPTSS reduced TARC and RANTES production and mRNA expression in TNF-α and IFN-γ-treated HaCaT cells. BPTSS inhibited IL-4, 5, and 13 production in mouse splenocytes. Our data will be a helpful information to upgrade quality control and anti-allergic effects of BPTSS.

• Asian Journal of Atmospheric Environment
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• v.5 no.4
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• pp.263-277
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• 2011

Global atmospheric $CO_2$ distributions were simulated with a chemical transport model (GEOS-Chem) and compared with space-borne observations of $CO_2$ column density by GOSAT from April 2009 to January 2010. The GEOS-Chem model simulated 3-D global atmospheric $CO_2$ at $2^{\circ}{\times}2.5^{\circ}$ horizontal resolution using global $CO_2$ surface sources/sinks as well as 3-D emissions from aviation and the atmospheric oxidation of other carbon species. The seasonal cycle and spatial distribution of GEOS-Chem $CO_2$ columns were generally comparable with GOSAT columns over each continent with a systematic positive bias of ~1.0%. Data from the World Data Center for Greenhouse Gases (WDCGG) from twelve ground stations spanning $90^{\circ}S-82^{\circ}N$ were also compared with the modeled data for the period of 2004-2009 inclusive. The ground-based data show high correlations with the GEOS-Chem simulation ($0.66{\leq}R^2{\leq}0.99$) but the model data have a negative bias of ~1.0%, which is primarily due to the model initial conditions. Together these two comparisons can be used to infer that GOSAT $CO_2$ retrievals underestimate $CO_2$ column concentration by ~2.0%, as demonstrated in recent validation work using other methods. We further estimated individual source/sink contributions to the global atmospheric $CO_2$ budget and trends through 7 tagged $CO_2$ tracers (fossil fuels, ocean exchanges, biomass burning, biofuel burning, net terrestrial exchange, shipping, aviation, and CO oxidation) over 2004-2009. The global $CO_2$ trend over this period (2.1 ppmv/year) has been mainly driven by fossil fuel combustion and cement production (3.2 ppmv/year), reinforcing the fact that rigorous $CO_2$ reductions from human activities are necessary in order to stabilize atmospheric $CO_2$ levels.

• Journal of Korean Society of Steel Construction
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• v.29 no.2
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• pp.135-145
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• 2017

This study is a secondary study that is a cyclic seismic test of High depth hybrid composite beam and column connection after the primary bending strength test of a high depth Hybrid composite beam. Total of 3 seismic test specimens were prepared to cyclic test. The bracket and beam web spliced by high strength bolt and the bracket and beam upper flange was spliced by welding. Test results showed that the seismic strength was higher than the plastic moment($M_p$) in the positive negative moment section, the requirement of composite intermediate moment frame wes satisfied. Therefore, the requirement of intermediate moment frame can be secured by applying the details of connection of this study results.

• Journal of Microbiology and Biotechnology
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• v.10 no.4
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• pp.514-517
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• 2000

Abstracts Six shikonin metabolites were obtained from human intestinal bacteria, Bacteriodes fragilis subsp. thetaotus. following biotransformation. The transformation of shikonin (1) was performed anaerobically for 3 day at $37^{\circ}C$ in thc bacterial suspension of B. Fagilis which was cultured overnight in GAM broth. The incubation mixture \vas extracted with EtGAc Lo give a dark-brown residue. The residue was apphed to a silica gel column, which was eluted successively with hexane (Fr. A), $CHCl_3$ (Fr. B), and $CHCl_3$:MeOH (9:I) (Fr. C). Six metabolites. Fr.A (2 and 3), Fr. B (6 and 7), and Fr. C (4 and 5) were isolated by repeated silica gel column chromatography, preparatlVe TLC, followed by Sephadex LH-20. In vitro cytotoxicities were tested against human tumor cell lines; PC-3 (prostate), ACHN (renal), A549 (lung), SW620 (colon), KS62 (leukemia), and Du145 (prostate). The shikonin metabolites 2. 4, 5, and 6 showed weaker cytotoxicity than the parenL shikonin (1). whereas shikonin monomenc metabolite 3 ($ED_{50}{\;}O.44-{\;}1.22{\;}\mu\textrm{g}/ml$) and dimeric metabolite 7 ($ED_{50}{\;}O.48-{\;}2.35{\;}\mu\textrm{g}/ml$) exhibited stronger activities compared with adriamycin, which was used as the positive control.ontrol.

• The Korean Journal of Food And Nutrition
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• v.11 no.3
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• pp.347-353
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• 1998

An antibiotic for methicillin resistant Staphylococcus aureus(MRSA) produced by Streptomyces lydicus YSK-681 was extracted by chloroform, and then purified by the C18 reversed-phase HPLC and silica gel column HPLC. The molecular weight of the purified antibiotic was determined from the FAB analysis MS an m/z 1022.4 and 1036.4(M+H)+, indicating that the isolated antibiotic consisted of two similar compounds with the molecular weight difference of 14 m/z value. With the aid of the various nuclear magnetic resonance(NMR) spectroscopic techniques such as 1H NMR, 13C NMR, DEPT and HMQC spectroscopy, the characteristics of function al groups were deduced as the hydroxyl group and leucine. The MIC values of the purified antibiotic were observed at 1∼32 $\mu\textrm{g}$/$m\ell$ against Gram-positive bacteria compared to > 125 $\mu\textrm{g}$/$m\ell$ against Gram-negative bacteria or fungi. The antibiotic was active at 8 $\mu\textrm{g}$/$m\ell$ of MIC90 and S180 at the concentration of 500 $\mu\textrm{g}$/$m\ell$.

• The Korean Journal of Zoology
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• v.29 no.1
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• pp.1-12
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• 1986

Electrophoretic, immunological, and column chromatography methods were used to determine the appearance and distribution of storage proteins in various organs during the metamorphosis of Bombyx mori L. Two storage proteins start to appear in haemolymph in early 5th instar stage and show the identical mobility with fat body proteins. These proteins show the high concentration in haemolymph in last instar stage but accumulate in fat body after pupation. Storage protein-2 shows the distinct pattern for general storage proteins in both male and females. This protein is involved with the formation of cuticle protein in late last instar stage and appears to be temperally deposited in midgut during the pupal stage. Also SP-2 shows the identity with vitellogenin electrophoretically and immunologically and especially the positive reaction with antibody against yolk protein during the pupal stage, demonstrating that the storage protein is closely related to the formation of yolk protein.