• Molecules and Cells
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• v.42 no.3
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• pp.252-261
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• 2019

The omega-3 fatty acid docosahexaenoic acid (DHA) is known to induce apoptosis and cell cycle arrest via the induction of reactive oxygen species (ROS) production and endoplasmic reticulum (ER) stress in many types of cancers. However, the roles of DHA in drug-resistant cancer cells have not been elucidated. In this study, we investigated the effects of DHA in cisplatin-resistant gastric cancer SNU-601/cis2 cells. DHA was found to induce ROS-dependent apoptosis in these cells. The inositol 1,4,5-triphosphate receptor ($IP_3R$) blocker 2-aminoethyl diphenylboninate (2-APB) reduced DHA-induced ROS production, consequently reducing apoptosis. We also found that G-protein-coupled receptor 120 (GPR120), a receptor of long-chain fatty acids, is expressed in SNU-601/cis2 cells, and the knockdown of GPR120 using specific shRNAs alleviated DHA-mediated ROS production and apoptosis. GPR120 knockdown reduced the expression of ER stress response genes, similar to the case for the pre-treatment of the cells with N-acetyl-L-cysteine (NAC), an ROS scavenger, or 2-APB. Indeed, the knockdown of C/EBP homologous protein (CHOP), a transcription factor that functions under ER stress conditions, markedly reduced DHA-mediated apoptosis, indicating that CHOP plays an essential role in the anti-cancer activity of DHA. These results suggest that GPR120 mediates DHA-induced apoptosis by regulating $IP_3R$, ROS, and ER stress levels in cisplatin-resistant cancer cells, and that GPR120 is an effective chemotherapeutic target for cisplatin resistance.

• Biomolecules & Therapeutics
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• v.29 no.1
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• pp.22-30
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• 2021

Till the 21st century, fatty acids were considered as merely building blocks for triglycerides, phospholipids, or cholesteryl esters. However, the discovery of G protein-coupled receptors (GPCRs) for free fatty acids at the beginning of the 21st century challenged that idea and paved way for a new field of research, merged into the field of receptor pharmacology for intercellular lipid mediators. Among the GPCRs for free fatty acids, free fatty acid receptor 4 (FFA4, also known as GPR120) recognizes long-chain polyunsaturated fatty acids such as DHA and EPA. It is significant in drug discovery because it regulates obesity-induced metaflammation and GLP-1 secretion. Our study reviews information on newly developed FFA4 agonists and their application in pathophysiologic studies and drug discovery. It also offers a potency comparison of the FFA4 agonists in an AP-TGF-α shedding assay.

• Korean Journal of Heritage: History & Science
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• v.47 no.4
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• pp.120-135
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• 2014

There is a necessity of re-research about Geumgangsaji temple site as reviewed recently confirmed typical temple arrangement of Baekje. The purposes of this study are, determine that building remains and layout patterns using Ground Penetrating Radar, and identify that the location and terrain changes of Geumgangsaji using aerial photographs and a numerical map by GIS. In the GPR result, it was confirmed that new building sites in the west and the north area which in Geumgangsaji is more wide. In addition, it was found that the temple is located on stable river terrace with low soil loss. And this site has spontaneous drainage system for the optimum position.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.850-854
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• 2012

This study is carried out in order to develop food materials for the promotion of rice consumption. In this study, we researched the physicochemical properties of extruded rice flour (ER) and gelatinization popped rice flour (GPR) by the extrusion process and by the popped method with milled rice and brown rice. The extrusion process used a couple of screw extruders. The extrusion parameter was kept constant at a feed moisture content of 25%, barrel temperature of $120^{\circ}C$ and screw speed of 400 rpm. GPR was prepared by batch popping machine after gelatinization of rice. In order to evaluate the physicochemical properties of ER and GPR, as well as the gelatinization rate, water soluble index (WSI), water adsorption index (WAI), DPPH radical scavenging activity and total dietary fiber content, the color value was carried out. The gelatinization rate was similar to 71.1~73.8%. Further, the results of WSI and WAI were increased at ER and GPR compared to the raw materials; ER was also higher than GPR. DPPH radical scavenging activity and total dietary fiber content showed a tendency to reduce after extrution and popping. As a result of the color value, the L value of ER decreased more than the raw materials, whereas GPR increased at a and b values.

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.334-341
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• 2008

Ballast track needs maintenance works because it is supported by the compressible trackbed and subgrade layers. Maintenance works are essential to secure riding comfort and extend the life cycle of it. The necessities of maintenance works are determined from track irregularities measured by EM120. Track irregularities is the results of the track deformation. Therefore, it is natural to evaluate the cause of it. This paper focuses on the points the track irregularities come from the trackbed and the subgrade. Nondestructive techniques, such as Ground Penetrating Radar (GPR) and Portable Falling Weight Deflectometer (PFWD) are applied to evaluate the trackbed conditions, ballast layer thickness and vertical track stiffness, in the test section 500m long of Gyungbu line. The trackbed investigation results are compared with the track irregularities measured by EM120 and maintenance works. Conclusively, it was found that some maintenance works were unnecessary on the test section.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.117-120
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• 2003

GPRS(General Packet Radio Service) 서비스는 circuit 기반의 GSM(Global System for Mobile Communication)의 기본 망구조를 이용하여 packet 서비스를 지원하도록 변형시킨 모델이다. 기본적으로 GPRS는 GSM의 많은 부분을 계승하여 서비스를 지원하고 있기 때문에 GSM이 가지고 있던 문제점을 그대로 이어받게 되었는데, 본 논문에서는 사용자 인증 프로시져등에서 문제시 될 수 있는 부분들에 대해 살펴보고, 이를 보완 할 수 있는 방법으로 공개키의 암호화 모드와 인증 모드를 사용한 인증 프로시져와 시스템 구조를 소개하고자 한다. 또한 공개키 구조의 인증을 사용함으로써 필요로 하게 되는 키 관리에 대한 방법을 제시하고 앞으로 해결해 나가야 될 문제에 대해 언급을 하고자 한다.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.2
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• pp.120-125
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• 2014

Conventional handheld metal detectors use a single induction coil to detect the metallic parts of explosive objects, and the detector generates an acoustic signal from its magnetic response to a metallic object so that an operator can confirm the existence of mines. Though metal detectors have very useful detection mechanisms to find mines, it is easy to cause a high false alarm ratio due to the detection of non-explosive metallic items such as cans, nails and other pieces of metal, etc. Also, because of the physical characteristic of a metal detector it is hard to detect non-metallic objects such as mines made of wood or plastic. Furthermore, the operator must move it to the left and right slowly and repeatedly to attain enough sensor signals to confirm the existence of mines using only a monotonous acoustic signal. To resolve the disadvantages of handheld detectors, many new approaches have been attempted, such as an arrayed detector and a visualization algorithm based on metal/non-metal sensor. In this paper, we introduce a visualization algorithm with a metal/non-metal complex sensor, an arrayed metal/non-metal sensor and the their testing and evaluation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.12
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• pp.592-596
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• 2005

Recently, substations have been constructed in GIS (Gas Insulated Switchgear) and indoor type because of the increasing difficulties of securing locations. In case of urban substations, it is also common that the substations are exclusively fed by underground cables. Sometimes, the infrastructures in urban area, such as communication facilities, are located near substations to be constructed. In this paper, we examined such a case that a branch office building of KT(Korea Telecom) was located near 154 kV underground GIS substation under construction with about 100 meters of the lateral distance between two facilities. GPR (Ground Potential Rise) at the substation and the transferred earth potential at the KT building through the earth in SLG (Single-Line-to- Ground) fault condition were investigated based on a series of computer simulations. The calculated earth potential at a distance of 100 m from the substation was below 120 V which satisfying the limit value of 650 V.

• Journal of Ginseng Research
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• v.46 no.2
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• pp.206-213
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• 2022

Ginsenoside Rb2 is an active protopanaxadiol-type saponin, widely existing in the stem and leave of ginseng. Rb2 has recently been the focus of studies for pharmaceutical properties. This paper provides an overview of the preclinical and clinical pharmacokinetics for Rb2, which exhibit poor absorption, rapid tissue distribution and slow excretion through urine. Pharmacological studies indicate a beneficial role of Rb2 in the prevention and treatment of diabetes, obesity, tumor, photoaging, virus infection and cardiovascular problems. The underlying mechanism is involved in an inhibition of oxidative stress, ROS generation, inflammation and apoptosis via regulation of various cellular signaling pathways and molecules, including AKT/SHP, MAPK, EGFR/SOX2, TGF-β1/Smad, SIRT1, GPR120/AMPK/HO-1 and NF-κB. This work would provide a new insight into the understanding and application of Rb2. However, its therapeutic effects have not been clinically evaluated. Further studies should be aimed at the clinical treatment of Rb2.