• 제목/요약/키워드: Free agent

검색결과 681건 처리시간 0.025초

제강 슬래그를 이용한 콘크리트의 동결융해에 대한 실험적 연구 (An Experimental Study on the Freezing and Thawing of Concrete Mixed with Steel Slag)

  • 정원섭;조성현;권기주;박성우;김진만
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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    • pp.48-53
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    • 2003
  • The steel slag, a by-product which is produced on the process of manufacturing steel by refining pig iron is mainly used as road materials after aging it. It is necessary to age steel slag for long time in air because the reaction with water and free-CaO in steel slag could make the volume expanded. Due to this reason it prevents steel slag from being used as aggregate of concrete. But steel slag used in this study is controled by a air-jet method which rapidly cools substance melted at a high temperature. Rapid cooling prevents from generating of free-CaO in steel slag. In this study, it was investigated that steel slag manufactured by air-jet method affects on concrete in the freezing and thawing. As results of this study, concrete mixed with steel slag was worse in the freezing and thawing than concrete mixed with sand in spite of using air entraining agent. To obtain durability of concrete in the freezing and thawing, it is desirable to mix 50% of steel slag in concrete per unit weight of volume.

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Fumonisin B1에 의한 세균바이러스 DNA손상 (Bacterial Virus DNA Damage Caused by Fumonisin B1)

  • 이길수;조성국
    • 한국환경성돌연변이발암원학회지
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    • 제19권1호
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    • pp.34-38
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    • 1999
  • Fumonisin B1 is a secondary metabolite of Fusarium moniliforme, a contaminant of corn and corn product. Fumonisin B1 has been shown to be responsible for major toxicological effects of the fungus in rats, horses, and pigs. Fumonisin B1 induced λ DNA fragmentation, which was increased with incubation time, reducing agent NADPH and metal ion (Cu2+). The DNA damage was inhibited by dimethyl sulfoxide (DMSO) or mannitol as radical scavenger for free radicals. DNA fragmentation, induced by fumonisin B1 in the presence of 1 mM NADPH and 0.1 mM CuCl2, was inhibited by 100 mM DMSO. By the in vitro reaction of fumonisin B1 with supercoiled plasmid pBR322 DNA, plasmid DNA was relaxed, eventually linearized in the agarose gel electrphoresis. From rifampicin sensitive E. coli CSH138 in bacterial mutagenesis system, the rifampicin resistant E. coli mutants were obtained by fumonisin B1. These results suggest that fumonisin B1 may be a possible environmental mutagen in bacterial mutagen assay system.

The Effects of Bamboo Extract on Human Melanocytes and B16 Melanoma Cells in vitro

  • Cho, Joon-Hwan;Lee, Ki-Moo;Kim, Nam-Soo;Kang, Won-Hyoung
    • 대한화장품학회지
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    • 제25권4호
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    • pp.133-143
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    • 1999
  • To identify inhibitory effect of Bamboo extract on melanogenesis, the effect was compared with arbutin, ascorbic acid, hydroquinone, and kojic acid on the melanin biosynthesis in B16 mouse melanoma cells and cultured human melanocytes. The cell viability of the agent was tested on cultured human melanocytes. We also examined its. free radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl(DPPH). Bamboo extract showed considerable effect against melanin production and did not reduce cell viability at the concentration tested. It also showed potent free radical scavenging activity.

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가상 공간에서 에이전트 생성을 위한 실시간 마커프리 모션캡쳐 시스템 (Real-time Marker-free Motion Capture System to Create an Agent in the Virtual Space)

  • 김성은;이란희;박창준;이인호
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 하계종합학술대회 논문집(3)
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    • pp.199-202
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    • 2002
  • We described a real-time 3D computer vision system called MIMIC(Motion interface f Motion information Capture system) that can capture and save motion of an actor. This system analyzes input images from vision sensors and searches feature information like a head, hands, and feet. Moreover, this estimates intermediated joints as an elbow and hee using feature information and makes 3D human model having 20 joints. This virtual human model mimics the motion of an actor in real-time. Therefore this system can realize the movement of an actor unaffectedly because of making intermediated joint for complete human body contrary to other marker-free motion capture system.

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항암성 백금화합물의 신장독성에 관한 연구 (Studies on the Mechanism of Nephrotoxicity Caused by Antitumor Platinum Complex)

  • 최병기;박영숙;정세영
    • Environmental Analysis Health and Toxicology
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    • 제8권3_4호
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    • pp.23-32
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    • 1993
  • This study was designed to elucidate the mechanism of nephrotoxicity caused by antitumor agent tetraphosphine platinum (II) complex (RC-1), which was synthesized as a tetraphosphine Pt (II) derivatives recently. Rats treated with RC-1 (20mg/kg/day) showed the increase of BUN value and malondialdehyde contents in kidney homogenate, compared to the control and which means the lipid peroxidation was a main cause of nephrotoxicity. In order to investigate the cytotoxic mechanism of RC-1, we also tested and revealed the generation of oxygen free radicals derived from neutrophil stimulated by RC-1 and interaction of the oxygen free radicals with the erythrocyte membrane. From the above results, we suggest that nephrotoxicity of general platinum (II) antitumor compounds as well as RC-1 were inhibited by radical scavengers.

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통초추출물의 항산화 활성 및 항노화효과 (Antioxidative Activity and Antiaging Effects of Tetrapanax papyriferum extract)

  • 노언주;김병관;김덕술
    • 한국응용과학기술학회지
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    • 제28권2호
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    • pp.219-224
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    • 2011
  • In this study, we evaluated the anti-oxidative, whitening and anti-wrinkle effect of Tetrapanax papyriferum extract. Tetrapanax papyriferum was extracted by two different solvents which were n-Hexane, ethyl acetate. The anti-oxidant activity was measured by free radical scavenging activity using DPPH (1,1-diphenyl-2-picrylhydrazyl radical). And the inhibitory activities of tyrosinase for whitening effect and collagenase, elastase for anti-wrinkle were investigated. For anti-oxidant activity, ethyl acetate fraction of Tetrapanax papyriferum extract showed more significant activity than n-Hexane fraction of Tetrapanax papyriferum extract. For whitening activity, n-Hexane fraction of Tetrapanax papyriferum extract exhibited strong inhibition effects compared with reference. Therefore, Tetrapanax papyriferum extract may be useful as a new antioxidant and whitening agent.

Ginsenoside Rgi is an Anti-apoptotic Agent

  • Zhang, Jun-Tian;Li, Jun-Qing
    • 고려인삼학회:학술대회논문집
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    • 고려인삼학회 1998년도 Advances in Ginseng Research - Proceedings of the 7th International Symposium on Ginseng -
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    • pp.12-20
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    • 1998
  • Primary neuronal culture was studied for observing effect of ginsenoside Rgl (Rgl) on serum-free medium induced apoptosis. Results showed that Rgl at concentration of 1 umol$.$ L-1 and 10 umol$.$L-1 could inhibit apoptosis, decrease intracellular calcium concentration in cultured cortical neurons, enhance SOD activity in both aged rat cortex and cultured cortical neurons, scavenge cytotoxic oxygen free radicals, decrease NO content and NOS activity in aged rat cortex and cultured cortical neurons, increase bel-2 gene expression in rat brain. These results provided new data for elucidating the anti-aging effect of Rgi. Rgl is considered to be a useful drug for treatment of Alzheimer's disease and brain aging.

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The Effects of Bamboo Extract on Human Melanocytes and B16 Melanoma Cells In vitro

  • Cho, Joon-Hwan;Lee, Kim-Moo;Kim, Nam-Soo;Kang, Won-Hyoung
    • 대한화장품학회:학술대회논문집
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    • 대한화장품학회 1999년도 IFSCC . ASCS 학술대회 발표 논문
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    • pp.133-143
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    • 1999
  • To identify inhibitory effect of Bamboo extract on melanogenesis, the effect was compared with arbutin. ascorbic acid, hydroquinone, and kojic acid on the melanin biosynthesis in Bl6 mouse melailoma cells and cultured hunlan melanocytes. The cell viability of the agent was tested on cultured human melanocytes. We also examined. its free radical scavenging activity on 1,1-dipheny1-2-picrylhydrazyl (DPPH). Bamboo extract showed considerable effect against melanin production and did not reduce cell viability at the concentration tested. It also showed potent free radical scavenging activity.

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PORTFOLIO CHOICE UNDER INFLATION RISK: MARTINGALE APPROACH

  • Lim, Byung Hwa
    • 충청수학회지
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    • 제26권2호
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    • pp.343-349
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    • 2013
  • The optimal portfolio selection problem under inflation risk is considered in this paper. There are three assets the economic agent can invest, which are a risk free bond, an index bond and a risky asset. By applying the martingale method, the optimal consumption rate and the optimal portfolios for each asset are obtained explicitly.