• Journal of Engineering Education Research
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• v.10 no.2
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• pp.19-43
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• 2007

The Korean Society for Engineering Education (KSEE) was founded in 1994, and the Journal of Engineering Education Research has published since 1998. The purpose of the study was to analyze the research methodologies and contents for all 126 papers which were published from 1998 to 2005. A statistical package SPSS(ver. 15.0) was used to analyze the coding data of all papers. The research contents were as follows: (1) A classification of the number of papers published according to year and researcher features (gender, institution, major field, number of authors, etc) was performed, (2) The analysis of research methodologies and contents of the papers published was performed, (3) Strategies to improve the quality of the journal were suggested by discussion from the analysis results. The results showed that the development research method was used most frequently, most papers were mode by major scholars of electrical and electronic engineering and scholars of Yonsei University made the most papers. In order to use the survey research method, the sampling methods were mainly used by total number, purposive, convenience, stratified sampling method, etc, questionnaire was used of 89.5%, descriptive statistics of frequency/% was used of 50%. To conduct the experimental research method, the models of nonequivalent groups posttest-only design and one-group pretest-posttest design were adopted, respectively. Finally, research strategies and new direction for improving the engineering education journal's papers at the section of discussion and suggestion were suggested.

• The Journal of the Acoustical Society of Korea
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• v.25 no.2
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• pp.49-55
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• 2006

Measurement of impact sound insulation of floor, by current Korean Standard KS F 2810-2. is to be made with peak levels over 4 point in a receiving room. But it is often the case that there is inconsistency in results at various receiving points in the receiving room. Such variations obviously have effects on the repeatability and reproducibility of measured data. The result shows that there are even 10 dB deviations in 63Hz octave band frequency range and relatively less variations are occurred in other low frequency ranges. Such variations seems to be coming from modal overlaps of the receiving room. According to current rating method of floor impact sound. KS F 2863-2, that may affect on the single number latins scheme. From the result of tests in this study, there are 2dB to 6dB differences in the sin91e number with the combination of measurement points. This means that the reduction of measurement variations from the microphone positions is needed for a better credibility of measurement results.

• Analytical Science and Technology
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• v.29 no.2
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• pp.94-103
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• 2016

An analytical method was developed to determine the amount of spinetoram (spinetoram J and spinetoram L) in livestock samples. The spinetoram was extracted with acetonitrile and purified through a primary secondary amine (PSA) sorbent. The spinetoram residues were then quantified and confirmed using a liquid chromatography–tandem mass spectrometer (LC-MS/MS) in the positive ion mode using multiple reactions monitoring (MRM). Matrix-matched calibration curves were linear over the calibration ranges (0.005-0.5 mg/kg) into a blank extract with r² > 0.994. The limits of detection and quantification were 0.002 and 0.01 mg/kg, respectively. The recovery results of spinetram ranged between 81.9-106.4% at different concentration levels (LOQ, 10LOQ, 50LOQ, n=5) with relative standard deviations (RSDs) less than 10%. All values were consistent with the criteria ranges requested in the Codex guidelines (CAC/GL40, 2003). An interlaboratory study was conducted to validate the method. The proposed analytical method proved to be accurate, effective, and sensitive for spinetoram determination. The method will be used as an official analytical method in Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.3
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• pp.159-165
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• 1997

This paper presents the optimum dimension of 89 ton class stow-net vessel with stern-fishing. The model of basic design is developed by using the optimization techniques referring to objective function and numerous constraints as follows; speed, fishing quantity, fishing days, catch per unit effort(CPUE), and weight/ratio of main dimensions, etc. Thus, the basic design of stow-net fishing vessel is built up by using the optimization of the design variables called the economic optimization criteria, and the objective function represents the criterion which is cost benefit ratio(CBR). The main conclusions are as follows. 1. S/W for decision of optimum hull size is developed in 89 ton class stow-net fishing vessel which is constructed with optimization of the design variables called the economic optimization criteria. 2. For optimum ship dimensions in 89 ton class stow-net fishing vessel, the hull dimensions can be obtained in the range of L= 27.3m, B = 6.6m, D = 2.80m, Cb = 0.695, T/D = 0.80, $\Delta$(displacement)=281.7ton with 10 knots.

• BMB Reports
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• v.39 no.2
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• pp.197-207
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• 2006

Cajanus indicus is a herb with medicinal properties and is traditionally used to treat various forms of liver disorders. Present study aimed to evaluate the effect of a 43 kD protein isolated from the leaves of this herb against chloroform induced hepatotoxicity. Male albino mice were intraperitoneally treated with 2mg/kg body weight of the protein for 5 days followed by oral application of chloroform (0.75ml/kg body weight) for 2 days. Different biochemical parameters related to physiology and pathophysiology of liver, such as, serum glutamate pyruvate transaminase and alkaline phosphatase were determined in the murine sera under various experimental conditions. Direct antioxidant role of the protein was also determined from its reaction with Diphenyl picryl hydraxyl radical, superoxide radical and hydrogen peroxide. To find out the mode of action of this protein against chloroform induced liver damage, levels of antioxidant enzymes catalase, superoxide dismutase and glutathione-S-transferase were measured from liver homogenates. Peroxidation of membrane lipids both in vivo and in vitro were also measured as malonaldialdehyde. Finally, histopathological analyses were done from liver sections of control, toxin treated and protein pre- and post-treated (along with the toxin) mice. Levels of serum glutamate pyruvate transaminase and alkaline phosphatase, which showed an elevation in chloroform induced hepatic damage, were brought down near to the normal levels with the protein pretreatment. On the contrary, the levels of anti-oxidant enzymes such as catalase, superoxide dismutase and glutathione-S-transferase that had gone down in mice orally fed with chloroform were significantly elevated in protein pretreated ones. Besides, chloroform induced lipid peroxidation was effectively reduced by protein treatment both in vivo and in vitro. In cell free system the protein effectively quenched diphenyl picryl hydrazyl radical and superoxide radical, though it could not catalyse the breakdown of hydrogen peroxide. Post treatment with the protein for 3 days after 2 days of chloroform administration showed similar results. Histopathological studies indicated that chloroform induced extensive tissue damage was less severe in the mice livers treated with the 43 kD protein prior and post to the toxin administration. Results from all these data suggest that the protein possesses both preventive and curative role against chloroform induced hepatotoxicity and probably acts by an anti-oxidative defense mechanism.

• Journal of Korea Soil Environment Society
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• v.4 no.1
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• pp.109-118
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• 1999

Recently, transport parameters of conservative solutes such as KCl in a porous medium have been successfully determined using time domain reflectometry (TDR) . This study was initiated to Investigate the applicability of TDR technique to monitoring the fate of a heavy metal ion in a sandy soil and the distribution of its concentration along travel distance with time. A column test was conducted in a laboratory that consists of monitoring both resident and flux concentrations of $ZnCl_2$in a sandy soil under a breakthrough condition. A tracer of $ZnCl_2$(10 g/L) was injected onto the top surface of the sample as pulse type as soon as a steady-state condition was achieved. Time-series measurements of resistance and electrical conductivity were performed at 10 cm and 20 cm of distances from the inlet boundary by horizontal-positioning of parallel TDR metallic rods and using an EC-meter for the effluent exiting the bottom boundary respectively. In addition. Zn ions of the effluent were analyzed by ICP-AES. Since the mode and position of concentration detected by TDR and effluent were different, comparison between ICP analysis and TDR-detected concentration was made by predicting flux concentration using CDE model accommodating a decay constant with the transport parameters obtained from the resident concentrations. The experimental results showed that the resident concentration resulted in earlier and higher peak than the flux concentration obtained by EC-meter, implying the homogeneity of the packed sandy soil. A close agreement was found between the predicted from the transport parameters obtained by TDR and the measured $ZnCl_2$concentration. This indicates that TDR technique can also be applied to monitoring heavy metal concentrations in the soil once that a decay constant is obtained for a given soil.

• Herbal Formula Science
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• v.31 no.1
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• pp.1-10
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• 2023

Objectives : The main aim of this study was to examine the LC-MS/MS used to identify phenolic compounds of CRE(Coptidis Rhizoma 70% EtOH Extract). Also, we investigated antioxidative activities and Anti-inflammatory activities. Methods : LC-MS/MS Analysis HPLC and LC-MS/MS were performed on a 1260 series HPLC system (Agilent Technologies, Inc., California, USA) and 3200 QTrap tandem mass system (Sciex LLC) operated in positive ion mode (spray voltage set at -4.5 kV). The solvent used was DW and Acetonitrile containing 0.1% formic acid, a gradient system was used at a flow rate of 0.5 mL/min for analysis, and a Prontosil C18 column (length, 250 mm; inner diameter, 4.6 mm; particle size, 5 ㎛; Phenomenex Co., Ltd., California, USA, Biochoff Chromatography) was used. The solvent conditions used in the mobile phases were 0-10 min at 10-15% B, 10-20 min at 20% B, 20-30 min at 25%, 30-40 min at 40%, 40-50 min at 70%, 50-60 min at 95%, and 60-70 min at 95%. The analysis was performed at a wavelength of 284 nm and a temperature of 35℃. The cell viability was measured using a 3-(4,5-dimethyethiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. We examined the effects of CRE on the lipopolysaccharide (LPS)-induced production of nitric oxide (NO) in a RAW 264.7 cells Results : The chemical analysis CRE by Liquid chromatography-tandem mass spectrometry (LC-MS/MS) confirmed that Rosmarinic acid, Ferrulic acid, 3-O-feruloylquinic acid, and 5-O-feruloylquinic acid as phenolic components. DPPH radical scavenging activity was the inhibitory activity of CRE showed at 200 ㎍/mL a statistically significant level. MTT assay demonstrated that the CRE did not have a cytotoxic effect in RAW 264.7 and LPS-induced RAW264.7 cells. Also, CRE reduced NO production in RAW 264.7 cells stimulated with LPS. Conclusions : Based on these findings, The chemical analysis 4 major components CRE such as Rosmarinic acid, Ferrulic acid, 3-O-feruloylquinic acid, and 5-O-feruloylquinic acid. Moreover, we confirmed that CRE has effects antioxidant and anti-inflammatory. The results demonstrate that CRE can be used as an antioxidant and a powerful chemopreventive ingredient against inflammatory diseases.

• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1125-1135
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• 2022

Damages by heavy snow does not occur very often, but when it does, it causes damage to a wide area. To mitigate snow damage, it is necessary to know, in advance, the depth of snow that causes damage in each region. However, snow depths are measured at observatory locations, and it is difficult to understand the spatial distribution of snow depth that causes damage in a region. To understand the spatial distribution of snow depth, the point measurements are interpolated. However, estimating spatial distribution of snow depth is not easy when the number of measured snow depth is small and topographical characteristics such as altitude are not similar. To overcome this limit, satellite images such as Synthetic Aperture Radar (SAR) can be analyzed using Differential Interferometric SAR (DInSAR) method. DInSAR uses two different SAR images measured at two different times, and is generally used to track minor changes in topography. In this study, the spatial distribution of snow depth was estimated by DInSAR analysis using dual polarimetric IW mode C-band SAR data of Sentinel-1B satellite operated by the European Space Agency (ESA). In addition, snow depth was estimated using geostationary satellite Chollian-2 (GK-2A) to compare with the snow depth from DInSAR method. As a result, the accuracy of snow cover estimation in terms with grids was about 0.92% for DInSAR and about 0.71% for GK-2A, indicating high applicability of DInSAR method. Although there were cases of overestimation of the snow depth, sufficient information was provided for estimating the spatial distribution of the snow depth. And this will be helpful in understanding regional damage-causing snow depth.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.645-653
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• 1999

Introduction : Although myocardial ischemia tends to occur more frequently than can he documented in ventilated patients, it has not been well studied on the factors related to the occurrence of the ischemia. Methods : To investigate the related factors to ischemia development, a prospective study was done in 95 cases with consecutive 73 patients who had received mechanical ventilation(MV) in MICU. In addition to 24 h holter monitoring, echocardiogram, electrolytes, cardiac enzymes, hemodynamic, and gas exchange measurements were done within 24 h after initiation of MV in 69 cases. The measurements were repeated at weaning period in 26 cases. The ischemia was defined by the ST segment changes; up-sloping depression more than 1.5 mm or down-sloping or horizontal depression more than 1.0 mm from isoelectric baseline for 80 ms following J point. Results : Twelve patients(12.6% in 95 cases) developed ischemia in total. The incidence of ischemia development showed an increased tendency in the initial 24 hr after MV (15.9%) and in patients with left-sided heart failure found by echocardiogram (18.2%) compared with that of the weaning period (3.8%) and patients without heart failure (10.9%) (P=0.12, P=0.09, in each). There were no differences in APACHE III score, baseline ECG findings, electrolytes abnormalities, use of inotropics or bronchodilators, presence of sepsis or shock, mode of ventilation, and survival rate according to the development of ischemia. Maximal heart rates and mean arterial pressure also were not different between patients with ($137.2{\pm}30.9/min$, $82.5{\pm}15.9$ mm Hg) and without ischemia ($l29.5{\pm}29.7/min$, $83.8{\pm}17.6$ mm Hg). Conclusion : Although the incidence of myocardial ischemia was 12.6% in total, there were no clinically predictable factors to the development of ischemia during mechanical ventilation.

• Herbal Formula Science
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• v.28 no.3
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• pp.255-269
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• 2020

Objectives : Hemistepta lyrata Bunge (Bunge) is a wild herb that has been used for managing fever and wound in Korean Traditional Medicine. The present study explored the effects of H. lyrata extract on liver X receptor (LXR) α-dependent lipogenic genes in hepatocyte-derived cells. Methods : After HepG2 cells or Huh7 cells were pre-treated with 1-10 ㎍/mL of H. lyrata extract or its fractionated extract for 0.5 h, the cells were subsequently exposed to LXR ligand for 6-24 h. Cell viability, LXR response element (LXRE)-driven luciferase activity, sterol regulatory element binding protein-response element (SREBP-RE)-driven luciferase activity, SREBP-1c expression, and mRNA levels of LXRα and its-dependent target genes were determined. In addition, LC-MS/MS analysis was conducted to explore major compounds in H. lyrata-chloroform fractionated extract #4 (HL-CF4). Results : Of various H. lyrata extracts tested, chloroform extract and its fractionated extract #4, HL-CF4, significantly decreased T0901317-mediated SREBP-1c expression. In addition, HL-CF4 significantly reduced LXRE atransactivation and LXRα mRNA expression without any cytotoxicity. Moreover, HL-CF4 prevented the SREBP-RE-driven luciferase activity and mRNA levels of fatty acid synthase and stearoyl-CoA desaturase-1 induced by T0901317. Results from LC-MS/MS analysis at positive/negative mode indicated that HL-CF4 contained several compounds showing m/z 197.1176 (C₁₁H₁₇O₃), 693.2913/227.1069 (C₃₈H₄₅O₁₂/C₁₅H₁₅O₂), 203.1797 (C₁₅H₂₃), 181.1225 (C₁₁H₁₇O₂), 591.2957 (C₃₅H₄₃O₈), 379.1040 (C₁₈H₁₉O₉), 409.1509 (C₂₀H₂₅O₉), 309.1348 (C₁₆H₂₁O₆), 391.1404 (C₂₀H₂₃O₈), and 669.2924/389.1248 (C₃₆H₄₅O₁₂/C₂₀H₂₁O₈). Conclusion : Based on its inhibition of the LXRα-dependent signaling pathway, H. lyrata chloroform extract and HL-CF4 have prophylactic potentials for managing non-alcoholic fatty liver.