• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.503-508
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• 2023

Tryptane derivatives are substances that treat acute migraines, and many studies have been conducted on analysis methods such as chromatography, electrochemistry, spectroscopy, and capillary electrophysiology. Recently, analytical chemists have become more interested in drug analysis and solving fundamental problems of biological importance. Therefore, in this study, the chemical properties of each derivative were investigated by calculating the total energy, band gap, electrostatic potential, and charge of Sumatriptan, Lizatriptan, Naratriptan, and Eletriptan using HyperChem8.0's semi-empirical PM3 method. As a result of this study, in the case of Sumatriptan, Naratriptan, and Eletriptan, chemical reactions are expected to proceed centering on oxygen and nitrogen atoms bonded to sulfur atoms. In addition, in the case of Rizatriptan without a sulfur atom, it was shown that the chemical reaction proceeds at the 17th and 19th nitrogens of the 5-membered heterocyclic compound.

• Analytical Science and Technology
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• v.19 no.4
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• pp.352-364
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• 2006

This study was performed to search for useful separation properties and elution orders of three GC columns (DB-1, DB-5MS, SPB-Octyl) for 209 PCBs congeners using M-1668A-0.01X-SET of the AccuStandard Inc.. In addition, to confirm the quantitative peak in peak pattern method, the IUPAC Nos. of PCBs congener peaks were identified with 4 Aroclor standards (Aroclor-1242, 1248, 1254 and 1260). The separation property of dioxin-like PCBs congeners by four columns (DB-1, DB-5MS, SP-2331 and SPB-Octyl) was excellent in SP-2331. DB-1 and SPB-Octyl columns are necessary to use with a column of other types.

• Clinical Endoscopy
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• v.57 no.3
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• pp.393-401
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• 2024

Background/Aims: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a highly accurate method for diagnosing pancreatic neuroendocrine tumors (PNETs); however, some PNETs are difficult to diagnose. Recently, the efficacy of needle-based confocal laser endomicroscopy (nCLE) in diagnosing solid pancreatic masses has been reported. However, the efficacy of nCLE in the diagnosis of PNETs remains unknown and only a small number of cases have been reported. Hence, this study aimed to evaluate the efficacy of nCLE in the diagnosis of PNETs. Methods: This single-center retrospective study evaluated 30 consecutive patients with suspected PNETs on contrast-enhanced computed tomography, who consented to nCLE combined with EUS-FNA and were diagnosed using EUS-FNA or surgical resection. The diagnostic criteria for PNETs using nCLE were based on the nesting and trabecular and glandular arrangement of tumor cell clusters surrounded by capillary vessels and fibrosis, as reported in previous studies. Results: The diagnosis using nCLE was classified into three categories: misdiagnosis in three cases (10%), non-diagnostic in six cases (20%), and diagnostic in 21 cases (70%). nCLE was able to diagnose PNET in one of the two cases with inconclusive EUS-FNA. Conclusions: Although further development of the resolution and optimization of the diagnostic criteria are required, nCLE may constitute a useful diagnostic option in cases of inconclusive EUS-FNA for PNETs.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.103-110
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• 2018

This study was conducted to investigate the optimum irrigation method for propagation of cutting strawberry ($Fragaria{\times}ananassa$ Duch. cv. Maehyang) plantlet in summer season. The cutting strawberry plantlets were planted in 24-cell tray ($60{\times}34{\times}10cm$) filled with commercial mixed medium (Tosilee) and placed in semi closed-type small plastic tunnel. Each semi closed-type small plastic tunnel was treated as follows; control (non-treatment), over head irrigation (twice a day), capillary mats irrigation (twice a day), or fog irrigation (30 minutes turn on and 10 minutes off from 8:00 to 18:00). The strawberry plantlets were rooted during 8 days in the semi closed-type small plastic tunnel, and then plastic film was removed. Growth parameters, such as plant height, root length, number of primary roots, petiole length, leaf length, leaf width, crown diameter, SPAD, leaf area, fresh and dry weights of the shoot and root, were measured at 61 days after cutting. Relative humidity in tunnel was high in the order by fog irrigation, over head irrigation, capillary mats, and the control as 72.5, 56.3, 45.8, and 29% on average, respectively. However, the air temperature was similar in all treatments. On the 4 and 8 days, the rooting rate of strawberry plantlet was significantly higher in the over head irrigation and fog irrigation treatments. Plant height, petiole length, crown diameter, and leaf area were highest in the over head irrigation and fog irrigation treatments. In addition, fresh and dry weights of shoot were greater in over head irrigation and fog irrigation treatments than the others. Dry weight of root was differed significantly heaviest in the fog irrigation treatment. However, root length, no. of primary roots, SPAD value, and fresh weight of root were not significantly different in all treatments. These results indicated that growth and rooting for propagation of cutting strawberry plantlet 'Maehyang' were best achievement in the over head irrigation and fog irrigation treatments.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.6
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• pp.980-989
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• 2009

Amur cork tree was extracted in methanol with the purpose of investigating the most effective extraction procedure for detecting the chromophore using the GC-MS analysis. Different procedures of waterbath and hotplate extractions were carried out and five different GC-MS instrument parameters including the operating temperatures in the GC capillary column and the MSD scan range were tested for their efficiencies. Berberine was determined by the detection of dihydroberberine at 15.0 min r.t. Hotplate was a better device for extracting amur cork tree than waterbath shaker either with or without presoaking in the room temperature. Water was not an adequate extraction medium for the berberine detection. The most effective GC-MS parameter was Method 4; the initial temperature at $50^{\circ}C$ followed by the temperature increase of $23^{\circ}C$/min until $210^{\circ}C$, then increase of $30^{\circ}C$/min until the final temperature reach at $305^{\circ}C$, then hold for 14 minutes to maintain the total run time 24.12 minutes. The MSD scan range for Method 4 was $35\sim400$m/z.

• The Korean Journal of Pesticide Science
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• v.4 no.1
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• pp.1-10
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• 2000

The purpose of this study is to establish the assessment techniques of hazardous chemicals by the development of analytical method of biological samples. In this study, we have developed an extraction method of nine pesticides used for rice paddy that resulted in high recovery from the spiked human urine by the liquid-liquid extraction with diethyl ether at pH 7.0. Calibration curve obtained from each pesticide standard using by gas chromatography/mass spectrometry/selected ion monitoring has shown good linearity and detection limits were the range of $0.4{\sim}2.0$ ng/mL in urine. As a biological monitoring, urine samples of local farmers exposed directly to nine pesticides in the field were collected and analyzed by GC/MS. Of the tested pesticides, metabolites of phenthoate assumed were identified by GC/MS analysis. No parent compound was detected.

• Korea-Australia Rheology Journal
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• v.21 no.1
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• pp.59-69
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• 2009

The prediction of pressure drop for a droplet flow in a confined micro channel is presented using FE-FTM (Finite Element - Front Tracking Method). A single droplet is passing through 5:1:5 contraction - straight narrow channel - expansion flow domain. The pressure drop is investigated especially when the droplet flows in the straight narrow channel. We explore the effects of droplet size, capillary number (Ca), viscosity ratio ($\chi$) between droplet and medium, and fluid elasticity represented by the Oldroyd-B constitutive model on the excess pressure drop (${\Delta}p^+$) against single phase flow. The tightly fitted droplets in the narrow channel are mainly considered in the range of $0.001{\leq}Ca{\leq}1$ and $0.01{\leq}{\chi}{\leq}100$. In Newtonian droplet/Newtonian medium, two characteristic features are observed. First, an approximate relation ${\Delta}p^+{\sim}{\chi}$ observed for ${\chi}{\geq}1$. The excess pressure drop necessary for droplet flow is roughly proportional to $\chi$. Second, ${\Delta}p^+$ seems inversely proportional to Ca, which is represented as ${\Delta}p^+{\sim}Ca^m$ with negative m irrespective of $\chi$. In addition, we observe that the film thickness (${\delta}_f$) between droplet interface and channel wall decreases with decreasing Ca, showing ${\delta}_f{\sim}Ca^n$ Can with positive n independent of $\chi$. Consequently, the excess pressure drop (${\Delta}p^+$) is strongly dependent on the film thickness (${\delta}_f$). The droplets larger than the channel width show enhancement of ${\Delta}p^+$, whereas the smaller droplets show no significant change in ${\Delta}p^+$. Also, the droplet deformation in the narrow channel is affected by the flow history of the contraction flow at the entrance region, but rather surprisingly ${\Delta}p^+$ is not affected by this flow history. Instead, ${\Delta}p^+$ is more dependent on ${\delta}_f$ irrespective of the droplet shape. As for the effect of fluid elasticity, an increase in ${\delta}_f$ induced by the normal stress difference in viscoelastic medium results in a drastic reduction of ${\Delta}p^+$.

• The Korean Journal of Pesticide Science
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• v.9 no.3
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• pp.237-242
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• 2005

This experiment was carried out to develop the fast and simple method for pesticide residue analysis by using solvent free solid injector (SFSI) and to validate the efficiency of the method developed for the residue analysis of the endocrine disruptor-like pesticides such as endosulfan, metribuzin, trifluralin and vinclozolin. The samples after freeze drying were sealed in glass capillary tubes and then introduced into the heated injector of gas chromatogaphy. The required pre-heating times were 1 min for endosulfan and trifluralin, 5 min for vinclozolin, and 10 min for metribuzin. The detection limits of endosulfan in chinese cabbages, metribuzin in lettuces, trifluralin in spinachs and vinclozolin in hot peppers were 0.05, 0.1, 0.05 and 0.05 ng, respectively and their recoveries were ranged from 74%, $98{\sim}107%$, $86{\sim}95%$ and $94{\sim}95%$, respectively. The detected level of metribuzine residue in field lettuce samples by using the SFSI was 0.6 ng/mg.

• Korean Journal of Environmental Agriculture
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• v.23 no.3
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• pp.148-157
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• 2004

A rapid analytical method was developed to determine multiple pesticide residues in apples and pears using gas-liquid chromatography (GLC). The samples were extracted with water-miscible solvents and purified by cleanup procedures serially comprising liquid-liquid partition and solid-phase extraction (SPE). Each analyte was separated and determined by a high-resolution GLC equipped with electron-capture detector (ECD) and nitrogen-phosphorous detector (NPD). A total of 196 pesticides, which were previously classified into 5 groups each for ECD and NPD based on their retention behaviors on the capillary column and responses to the detector, were subjected to the recovery experiment. In compliance with the analytical criteria, 70 to 120% of recovery and less than 20% relative standard deviation the proposed method could be successfully applied to analyze 136 and 133 pesticide residues in apples and pears, respectively, which enabled not only rapid screening but quantitation of the residues. Even though less reliability was resulted from unacceptable recovery range, rest of pesticides including 43 and 45 analyzes in apples and pears, could be also detected for their identity. The proposed method fliled to cover 17 and 18 pesticides for apples and pears, which mostly showed high polarity or heat-lability but could be suitable far fast surveilance or monitoring of fruit harvests.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.558-564
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• 2021

The water purifier market has increased rapidly in recent years. The welding technology of the evaporator is a key component that determines the level of ice production and the cold water performance of an ice purifier. The finger type evaporator of an ice purifier can remove ice and is divided largely into an instant heat method and a hot gas method. In the hot gas type evaporator, particularly during the production process, the pinhole phenomenon inside the copper pipe and clogging problems occur intermittently when welding high-pressure pipes due to the high-temperature oxygen welding. Its use in a water purifier can cause a problem in that ice and cold water do not form, and repairs cannot be made on site. To solve this problem, in this study, a cap jig was applied to improve the welding defect of the hot gas evaporator. In addition, the oxygen welding flame size was adjusted so that the heat source could be well supplied to the cap jig, and the effectiveness was confirmed through a wave pressure test, a test, and a thermal shock test.