• The Korean Journal of Nuclear Medicine
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• v.35 no.5
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• pp.334-341
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• 2001

Purpose: Ascorbic acid us known to act as an antioxidant. Therefore, it can be used in increasing the efficiency of radiochemical labeling of Technetium-99m setamibi by inhibition of oxidation of $Sn^{2+}$ at low concentration. We intended to estimate the efficiency of radiochemical labeling and the stability of the newly formed formulation when ascorbic acid was added to a commercial kit. Materials and Methods: Synthesis of sestamibi was performed according to Dong-A's patent procedure (No.10-2001-0012877). First, we undertook a study to evaluate the efficiency of radiochemical labeling of sestamibi containing ascorbic acid. The stability of the vials was assessed using either $7.5{\mu}g\;or\;75{\mu}g$ of ascorbic acid, added to commercial vials under the accelerated condition(Temp : $40^{\circ}C{\pm}2^{\circ}C$, Relative humidity : $75{\pm}5%$). Results: Sestamibi was synthesized in overall 35-40% yield over 5 steps from a commercially available methallyl chloride as a starling material. When ascorbic acid was added, the efficiency of radiochemical labeling was maintained compared to the vial with no ascorbic acid. The accelerated test showed that the addition of ascorbic acid inhibited the oxidation of $Sn^{2+}$ ion by antioxidation mechanism. Also, the efficiency of radiochemical labeling of this vial after 9 months was nearly the same as the starting point. Therefore, the storage period of the kit is likely to be extended. Taken together, it suggests that the addition of ascorbic acid as a stabilizer is desirable. Conclusion: To increase the stability of a sestamibi cold kit, it is desirable to add ascorbic acid as a stabilizer to the commercial formulation.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.78-83
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• 2013

BACKGROUND: This study was performed to investigate the change of deltamethrin residue after spraying for control of hygienic insects in bush of levee at Bansuk-dong stream (A) and Juk-dong ditch (B) in Yuseong, Daejeon. The drop concentrations and disappearance of deltamethrin residue in stream water were determined to evaluate the toxic effects of stream ecosystem. METHODS AND RESULTS: Water samples were collected at 7 points including 0, 5, 10, 20, 40, 70 and 100 m downstream from the deltamethrin spraying point. Water sample was partitioned into dichloromethane, and was determined with GC/${\mu}$-ECD. Limit of Quantitation of deltamethrin was 0.04 ${\mu}g/L$. Recoveries of deltamethrin at two fortification levels of 0.4 and 2.0 ${\mu}g/L$ were $91.57{\pm}3.13%$(n=3) and $94.40{\pm}4.59%$(n=3) in A stream, and $88.24{\pm}3.33%$(n=3) and $85.20{\pm}3.73%$(n=3) in B stream, respectively. Residue of A stream were from <0.04 ${\mu}g/L$ to 0.48 ${\mu}g/L$ and B stream were from 0.08 ${\mu}g/L$ to 14.95 ${\mu}g/L$ under practice application condition. And residues were from <0.04 ${\mu}g/L$ to 0.2 ${\mu}g/L$ in A stream treated deltamethrin with 1.0 mg level at the upper region. CONCLUSION(S): Practice application of deltamethrin for the pest control of waterside was not much shown toxic effect to ecosystem of stream.

• Economic and Environmental Geology
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• v.43 no.5
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• pp.467-475
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• 2010

The Landsat and ASTER data have been used in mineralogical and lithological studies, and they have also proved to be useful tool in the initial steps for mineral exploration throughout Nevada mining district, US. Huge pyrophyllite quarry mines, including Jungang, Samsung, Kyeongju, and Naenam located in the southeastern part of Gyeongsang Basin. The geology of study area consists mainly of Cretaceous volcanic rocks, which belong into Cretaceous Hayang and Jindong Group. They were intruded by Bulgugsa granites, so called Sannae-Eonyang granites. To extraction of Ratio model for pyrophyllite deposits, tuffaceous rock and pyrophyllite ores from the Jungang mine used in reflectance spectral analysis and these results were re-sampled to Landsat and ASTER bandpass. As a result of these processes, the pyrophyllite ores spectral features show strong reflectance at band 5, whereas strong absorption at band 7 in Landsat data. In the ASTER data, the pyrophyllite ores spectral features show strong absorption at band 5 and 8, whereas strong reflectance at band 4 and 7. Based on these spectral features, as a result of application of $Py_{Landsat}$ model to hydrothermal alteration zone and other exposed sites, the DN values of two different areas are 1.94 and 1.19 to 1.49, respectively. The differences values between pyrophyllite deposits and concrete-barren area are 0.472 and 0.399 for $Py_{ASTER}$ model, 0.452 and 0.371 for OHIb model, 0.365 and 0.311 for PAK model, respectively. Thus, $Py_{ASTER}$ and $Py_{Landsat}$ model proposed from this study proved to be more useful tool for the extraction of pyrophyllite deposits relative to previous models.

• Journal of Life Science
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• v.26 no.11
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• pp.1313-1319
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• 2016

Cancer is a complex disease heterogeneously composed of various types of cells including cancer stem-like cells responsible for relapse and chemoresistance in the tumor microenvironment. The conventional two-dimensional cell culture-based platform has critical limitations for representing the heterogeneity of cancer cells in the three-dimensional tumor niche in vivo. To overcome this insufficiency, three-dimensional cell culture methods in a scaffold-dependent or -free physical environment have been developed. In this study, we improved and simplified the HCT-8 colon cancer cell-based spheroid culture protocol and evaluated the relationship between cancer stemness and responses of chemosensitivity to 5- Fluorouracil (5-FU), a representative anticancer agent against colon cancer. Supplementation with defined growth factors in the medium and the culture dish of the regular surface with low attachment were required for the formation of constant-sized spheroids containing $CD44^+$ and $CD133^+$ colon cancer stem cells. The chemo-sensitivities of $CD44^+$ cancer stem cells in the spheroids were much lower than those of $CD44^-$ non-stem-like cancer cells, indicating that the chemoresistance to 5-FU is due to the stemness of colon cancer cells. Taken together, the inflammation and oncogenic gut environment-sensitive HCT-8 cell-based colon cancer spheroid culture and comparative evaluation using the simplified model would be an efficient and applicable way to estimate colon cancer stemness and pharmaceutical response to anticancer drugs in the realistic tumor niche.

• Analytical Science and Technology
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• v.27 no.3
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• pp.172-180
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• 2014

Fenpyrazamine which is a pyrazole fungicide class for controlling gray mold, sclerotinia rot, and Monilinia in grapevines, stone fruit trees, and vegetables has been registered in republic of Korea in 2013 and the maximum residue limits of fenpyrazamine is set to grape, peach, and mandarin as 5.0, 2.0, and 2.0 mg/kg, respectively. Very reliable and sensitive analytical method for determination of fenpyrazamine residues is required for ensuring the food safety in agricultural products. Fenpyrazamine residues in samples were extracted with acetonitrile, partitioned with dichloromethane, and then purified with silica-SPE cartridge and eluted with hexane and acetone mixture. The purified samples were determined by HPLC-UVD and confirmed with LC-MS and quantified using external standard method. Linear range of fenpyrazamine was between $0.1{\sim}5.0{\mu}g/mL$ with the correlation coefficient (r) 0.999. The average recovery ranged from 71.8 to 102.7% at the spiked level of 0.05, 0.5, and 5.0 mg/kg, while the relative standard deviation was between 0.1 and 7.3%. In addition, limit of detection and limit of quantitation were 0.01 and 0.05 mg/L, respectively. The results revealed that the developed and validated analytical method is possible for fenpyrazamine determination in agricultural product samples and will be used as an official analytical method.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.3
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• pp.253-262
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• 2009

The present study was conducted to develop a rapid and accurate method of evaluating chemical composition of total mixed ration (TMR) for dairy cows using near infrared reflectance spectroscopy (NIRS). A total of 253 TMR samples were collected from TMR manufacturers and dairy farms in Korea. Prior to NIR analysis, TMR samples were dried at $65^{\circ}C$ for 48 hour and then ground to 2 mm size. The samples were scanned at 2 nm interval over the wavelength range of 400-2500 nm on a FOSS-NIR Systems Model 6500. The values obtained by NIR analysis and conventional chemical methods were compared. Generally, the relationship between chemical analysis and NIR analysis was linear: $R^2$ and standard error of calibration (SEC) were 0.701 (SEC 0.407), 0.965 (SEC 0.315), 0.796 (SEC 0.406), 0.889 (SEC 0.987), 0.894 (SEC 0.311), 0.933 (SEC 0.885) and 0.889 (SEC 1.490) for moisture, crude protein, ether extract, crude fiber, crude ash, acid detergent fiber (ADF) and neutral detergent fiber (NDF), respectively. In addition, the standard error of prediction (SEP) value was 0.371, 0.290, 0.321, 0.380, 0.960, 0.859 and 1.446 for moisture, crude protein, ether extract, crude fiber, crude ash, ADF and NDF, respectively. The results of the present study showed that the NIR analysis for unknown TMR samples would be relatively accurate. Use of the developed NIR calibration curve can obtain fast and reliable data on chemical composition of TMR. Collection and analysis of more TMR samples will increase accuracy and precision of NIR analysis to TMR.

• Journal of Soil and Groundwater Environment
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• v.6 no.4
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• pp.51-59
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• 2001

Column and box tests were performed to investigate the removal efficiency of NAPL using the surfactant enhanced flushing In heterogeneous medium. Homogeneous Ottawa sand and heterogeneous soil were used to verify the increase of remediation efficiency for the surfactant enhanced flushing in column test. Box tests with two different heterogeneous sub-structure were performed to quantify the capability of the surfactant enhanced flushing as a remediation method to remove NAPL from the heterogeneous medium. Two different grain size sand layers were repeated in the box to simulate the heterogeneous layer formation and the modified fault structure was built to simulate the fault system in the box. O-xylene as a LNAPL and PCE as a DNAPL were used and oleamide as a non-ionic surfactant. The maximum NAPL effluent concentration with 1% oleamide flushing in the homogeneous column test increased about 460 times compared to that with only water flushing and about 250 times increased in the real soil column test. In heterogeneous medium, the maximum effluent concentration increased about 150 times in 1% oleamide flushing and most of NAPL were removed from the box within 8 pore volume flushing, suggesting that the removal efficiency increased very much compared to in only water flushing. Results investigated the capability of the surfactant enhanced remediation method to remove NAPL even in heterogeneous medium.

• Journal of Chest Surgery
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• v.35 no.1
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• pp.1-10
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• 2002

Background: Despite the relatively high mortality rates in the chronic heart failure model induced by coronary artery ligation are relatively high, this model has been a subject of continuos research because of its clinical correlation. Chronic heart failure model of large-sized animals is very useful to analyse mechanical or biological effects on circulatory system which is difficult in small-sized animals. The purpose of this study is to establish the heart failure model by coronary artery ligation in sheep. Material and Method: Among 9 Corridale sheep, the homonymous artery and the diagonal branch were ligated simultaneously in 2 sheep and remaining 7 sheep were assigned to successive ligation of both arteries at an interval of 1 hour. Both coronary arteries were ligated from the point 40% proximal to the apex of the heart. Hemodynamic and echocardiographic parameters were analyzed before the ligation of the coronary artery, after the ligation of the homonymous artery, and after additional ligation of the diagonal branch. The experimental animals were sacrificed after 2 or 3 months of growth and histopathologic studies were performed Result: Immediate postoperative death occurred in the 2 sheep that had received simultaneous ligation of the homonymous artery and diagonal branch. On the other hand, all the 7 sheep that were lifated in succession were survived up to 3 months. Arterial pressure was sifnificantly decreased immediately after ligation of the homonymous artery(p<0.05), and the cardiac output was decreased and pulmonary capillary wedge pressure was increased after further ligation of the diagonal branch(p<0.05). Central venous pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, left ventricular end-diastolic dimension and end-systolic dimension were markedly increased 3 months after ligation of coronary arteries. Anteroseptal akinesia or dyskinesia was developed after the ligation of coronary arteries. Histopathologic study revealed we]1-demarcated ischemic area of fibrosis. Conclusion: Using methods of successive ligation of the homonymous artery and diagonal branch, chronic heart failure model could be reliably established in sheep.

• The Korean Journal of Financial Management
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• v.12 no.1
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• pp.167-186
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• 1995

기업인수합병(M&A) 시장의 활성화에 따라 적대적 공개매수를 방어하기 위한 반인수조치(Antitakeover Techniques)들에 관한 관심도 고조되고 있다. 지금까지 널리 알려져 있는 대표적인 반인수 조치들은 Fair Price Amendment(FPA), Classified Board Amendment(CBA)와 Poison Pills(PP) 등이다. 이들 대표적 세 반인수조치들 중에서 FPA와 CBA 채택의 경우는 주주들의 사전 승인이 요구되는데 반하여 PP는 주주들의 사전 승인없이 채택이 가능한 반인수조치이다. 이처럼 상이한 반인수조치들의 채택은 채택기업의 가치에 상이한 부의 효과를 미치는데, 이 분야의 많은 실증적연구 결과들이 보고되고 있다. 본 연구에서는 표본기업으로 현재까지 상호개별적으로 연구되어 왔던 두가지 반인수조치(FTA, CBA)에 PP와 비채택기업도 포함시키고 있다. 지금까지의 반인수조치 채택에 따른 기업가치에 미치는 부의 효과에 관한 연구결과를 확인해보고, 반인수조치 채택에 관한 경영자의 의사결정과 경영자의 부 사이에 체계적인 관계가 존재하는지를 실증분석하고자 한다. 여기서 경영자의 부는 기업내부자 지분율과 기업내 경영자를 위한 Golden Parachute의 존재 유무로 측정한다. 본 연구에서는 3개의 가설을 설정하였다. 가설1: 만일 경영자가 주주의 이익을 희생하면서 자신의 이익을 위한 반인수조치를 채택한다면, 반인수조치 채택의 공표는 평균적으로 기업가치에 부(-)의 효과를 보일 것이다. 가설2: 경영자의 내부지분율이 낮을때 경영자들은 주주에게 가장 해로운 반인수조치를 선택할 것이다. 가설3: Golden Parachute가 존재하지 않을때 경영자들은 주주에게 가장 해로운 반인수조치를 채택할 것이다. 본 연구의 대상기업들중에서 반인수조치 채택 기업들은 IRRC 1990년도판에서 수집되었고, 대칭표본 기업으로 반인수조치를 채택하지 않은 기업들은 CRSP 파일에서 기업규모, SIC 코드를 대응시켜 선정하였다. 임원, 관계이사들과 친인척을 포함하는 내부자의 지분과 Golden Parachute 존재 여부는 이 연구의 표본기업들의 Proxy Statement에서 수집하였다. 최종 표본기업은 FPA 채택기업, CBA 채택기업, PP채택기업, 그리고 비채택기업으로 4개의 상호 배타적인 기업 그룹으로 구성되었다. 본 연구는 Event Study와 Multinomial Logistic Regession의 두가지 실증분석 방법을 사용하였다. Event Study방법론은 반인수조치 채택 공표시 초과수익률을 조사하기 위해 사용하였다. Multinomial Logistic Regession은 선택된 반인수조치 종류와 설명 변수들(내부자 지분율, Golden Parachute)간에 체계적인 관계가 존재하는지를 검증하기 위해 사용되었다. 반인수조치들을 채택하는 기업들은 반인수조치를 채택하고 있지 않은 기업들에 비해 내부자 지분율이 낮게 나타났으며, 반인수조치 중 PP를 채택한 기업에서 가장 낮은 내부지분율을 보이고 있다. GP 채택을 보면 PP를 선택한 기업의 50%가 GP를 채택하였다. 본 연구에서 반인수조치 채택 발표일 하루 전후의 초과수익률을 조사한 결과는 반인수조치 미채택기업, CBA, FPA 채택기업들의 초과수익률은 통계적으로 의미가 없었으나, PP채택에 따른 초과수익률은 의미 있는 부(-)의 값을 나타냈다. 이와같이 CBA와 FPA채택기업들은 주주의 부를 감소시키지 않았으나 PP채택기업들은 주주의 부를 감소시켰다. 따라서 경영자는 주주의 이익을 희생시키면서 자신의 이익을 위해 PP를 선택하고 있음을 보여 주고 있다. 연구결과는 내부자 지분율의 크기가 경영자와 주주간의 이해를 효과적으로 일치시키고 있음을 제시하고 있다. 즉, 내부자 지분율이 큰 기업일수록 반인수조치를 채택하지 않거나 반인수조치 채택시에 주주의 이익에 반하지 않은 반인수조치를 선택하는 경향이 높다. Golden Parachute이 존재하는 기업은 FPA를 채택하거나 반인수조치를 채택하지 않는 것보다 PP나 CBA를 채택하는 경향이 더 높다. 한편 기업에서의 GP의 존재가 경영자의 가장 해로운 반인수조치 선택을 억제하지 못함을 보여주고 있는데, 이는 GP가 비효과적인 계약메카니즘임을 제기한다. GP가 경영자와 주주간의 이해를 일치시키도록하는 계약이라기 보다는 차라리 기업방어전략이 비효과적일때 경영자 자신의 안전판으로 제공되고 있음을 보여준다. 이 논문의 주요공헌은 기업내부자 지분율의 크기와 GP의 존재가 반인수조치 선택에 체계적인 영향을 미치고 있음을 보여준 것이다. 여기서 사용된 Multinomial Logistic모델은 내부지분을 크기와 GP의 존재가 PP또는 CBA가 채택될 것인지를 예측할 수 있게 한다.

• Journal of Nutrition and Health
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• v.51 no.4
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• pp.275-286
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• 2018

Purpose: Our previous study demonstrated that persimmon (Diospyros kaki Thumb.) at different stages of ripening provided different protective effects against high-fat/cholesterol diet (HFD)-induced dyslipidemia in rats. In this study, we compared the metabolites profile and gene expressions related to triglyceride (TG)/cholesterol metabolism in vitro and in vivo after treating with persimmon water extracts (PWE) or tannin-enriched persimmon concentrate (TEP). Methods: Primary and secondary metabolites in test materials were determined by GC-TOF/MS, UHPLC-LTQ-ESI-IT-MS/MS, and UPLC-Q-TOF-MS. The expression of genes related to TG and cholesterol metabolism were determined by RT-PCR both in HepG2 cells stimulated by oleic acid/palmitic acid and in liver tissues obtained from Wistar rats fed with HFD and PWE at 0, 150, 300, and 600 mg/d (experiment I) or TEP at 0, 7, 14, and 28 mg/d (experiment II) by oral gavage for 9 weeks. Results: PLS-DA analysis and heatmap analysis demonstrated significantly differential profiling of metabolites of PWE and TEP according to processing of persimmon powder. In vitro, TEP showed similar hypolipidemic effects as PWE, but significantly enhanced hypocholesterolemic effects compared to PWE in sterol regulatory element-binding protein 2 (SREBP2), HMG-CoA reductase (HMGCR), proprotein convertase subtilisin/kexin type 9 (PCSK9), cholesterol $7{\alpha}-hydroxylase$ (CYP7A1), and low density lipoprotein receptor (LDLR) gene expression. Consistently, TEP and PWE showed similar hypolipidemic capacity in vivo, but significantly enhanced hypocholesterolemic capacity in terms of SREBP2, HMGCR, and bile salt export pump (BSEP) gene expression. Conclusion: These results suggest that column extraction after hot water extraction may be a good strategy to enhance tannins and long-chain fatty acid amides, which might cause stimulation of hypocholesterolemic actions through downregulation of cholesterol biosynthesis gene expression and upregulation of LDL receptor gene expression.