• 제목/요약/키워드: Hydrogen generation

검색결과 814건 처리시간 0.028초

지질산화생성물의 DNA손상작용 및 그 억제기구 (DNA Damage of Lipid Oxidation Products and Its Inhibition Mechanism)

  • 김선봉;강진훈;박영호
    • 한국수산과학회지
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    • 제20권5호
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    • pp.419-430
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    • 1987
  • 지질산화생성물에 의한 DNA손상작용 및 그 억제 기구를 밟히기 위하여 linoleic acid와 plasmid DNA와의 모델계를 통하여 검토하였는데, 그 결과를 요약하면 다음과 같다. 1. Linoleic acid의 산화에 의하여 DNA가 손상되었으며, 그 정도는 linoleic acid의 양이 많을 수록 크게 나타났다. 2. Linoleic acid의 산화에 의한 DNA손상작용은 POV 100 mea/kg이하인 산화초기에서도 빠르게 진행되었다. 산화초기의 DNA손상작용에는 활성산소 종의 관여가 크게 나타났는데, 그 중에서도 일중항 산소와 superoxide anion의 영향이 큰 것으로 나타났다. 3. 지질 2차반응생성물인 malonaldehyde와 hexanal의 DNA손상작용은 linoleic acid경우와는 달리 활성산소종과는 무관하였으며 DNA와 와의 복합체형성에 의하였다. 4. Linoleic acid hydroperoxide의 DNA 손상작용은 linoleic acid의 초기신화에 의한 DNA손상작용 보다 크게 나타났고, 활성산소종의 영향은 없었다. 5. 지진산화생성물에 의한 DNA손상 작용은 천연 항산화성분(마늘 및 생강추출물) 및 활성산소소거제($\alpha-tocopherol 및 superoxide dismutase$의 첨가에 의하여 크게 억제되었다. 특히 . 마늘 및 생강추출물은 활성산소종의 생성을 비롯하여 공액 diene 및 POV의 증가 또한 크게 억제하였다.

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다양한 In 조성을 가진 InGaN/GaN Multi Quantum Well의 효과적인 광전기화학적 물분해 (Dependence of Doping on Indium Content in InGaN/GaN Multiple Quantum Wells for Effective Water Splitting)

  • 배효정;방승완;주진우;하준석
    • 마이크로전자및패키징학회지
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    • 제25권3호
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    • pp.1-5
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    • 2018
  • 본 연구에서는 InGaN/GaN multi quantum well (MQW)에서 Indium (In) 도핑효과에 따른 광전기화학적 특성을 관찰하였다. 기판으로는 Sapphire을 사용하였고, 각 Quantum well (QW)을 구성하고 있는 InGaN의 조성을 다르게 하였다. 투과도 측정 결과 일정한 In 조성을 가진 InGaN/GaN MQW에 비해 각 QW의 In 조성을 다르게 한 InGaN/GaN MQW에서 흡수도가 향상되는 것을 확인할 수 있었다. 이는 각각 다른 In 조성을 가진 InGaN 층이 더 넓은 영역의 스펙트럼 에너지를 가지는 빛을 흡수하기 때문인 것으로 생각된다. 광학적 특성을 평가하기 위해 진행한 상온 photoluminescence (PL) 실험을 진행한 결과, 역시 다양한 In 조성을 가진 InGaN/GaN MQW이 더 넓은 파장에서 발광이 나타나는 것을 확인할 수 있었다. 이들 샘플에 대한 광전기화학적 특성평가를 통하여, gradation In 조성을 가지고 있는 InGaN/GaN MQW이 일정한 In 조성을 가지는 InGaN/GaN MQW에 비해 광전기화학적 물분해 능력이 월등히 향상됨을 확인하였다.

히로시마에서 후쿠시마까지, 핵과 미술가의 대응 (From Hiroshima to Fukushima: Nuclear and Artist Response in Japan)

  • 최태만
    • 미술이론과 현장
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    • 제13호
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    • pp.35-71
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    • 2012
  • The purpose of this essay is to examine the responses of artists on nuclear experiences through an analysis of the nuclear images represented in contemporary Japanese art. Japan has previously as twice experienced nuclear disaster in 20th century. The first atomic bombs were dropped in 1945 as well as the 5th Fukuryumaru, Japanese pelagic fishing boat, exposed by hydrogen bomb test operated by the US in 1954 nearby Bikini atoll. Due to Tsunami taken place by the great earthquake that caused the meltdown of Fukushima Nuclear Power Plant in March 2010, Japan is being experienced a nuclear disaster again. Despite practical experiences, comtemporary Japanese art has avoided the subject of nuclear disasters since the end of the Asia-Pacific War for a variety of reasons. Firstly, GHQ prohibited to record or depict the terrible effect of atomic bomb until 1946. Secondly, Japanese government has tried to sweep the affair under the carpet quite a while a fact of nuclear damage to their people. Because Japan has produced numerous war record paintings during the Second World War, in the aftermath of the defeated war, most of Japanese artists thought that dealing with politics, economics, and social subject was irrelevant to art as well as style of amateur in order to erase their melancholic memory on it. In addition, silence that was intended to inhibit victims of nuclear disasters from being provoked psychologically has continued the oblivion on nuclear disasters. For these reasons, to speak on nuclear bombs has been a kind of taboo in Japan. However, shortly after the atomic bomb dropped on Hiroshima, the artist couple Iri and Toshi Maruki visited to ruin site as a volunteer for Victim Relief. They portrayed the horrible scenes of the legacy of nuclear bomb since 1950 based on their observation. Under the condition of rapid economical growth in 1960s and 1970s, Japanese subculture such as comics, TV animations, plastic model, and games produced a variety of post apocalyptic images recalling the war between the USA and Japanese militarism, and battle simulation based on nuclear energy. While having grown up watching subculture emerged as Japan Neo-Pop in 1990s, New generation appreciate atomic images such as mushroom cloud which symbolizes atomic bomb of Hiroshima. Takashi Murakami and other Neo-Pop artists appropriate mushroom cloud image in their work. Murakami curated three exhibitions including and persists in superflat and infantilism as an evidence in order to analyze contemporary Japanese society. However, his concept, which is based on atomic bomb radiation exposure experience only claimed on damage and sacrifice, does not reflect Japan as the harmer. Japan has been constructing nuclear power plants since 1954 in the same year when the 5th Fukuryumaru has exposed until the meltdown of Fukushima Nuclear Plant although took place of nuclear radiation exposures of Three Mile and Chernobyl. Due to the exploding of Fukushima Nuclear Power Plant, Japan reconsiders the danger of nuclear disaster. In conclusion, the purpose of this paper may be found that the sense of victim which flowed in contemporary art is able to inquire into the response of artist on the subject of nuclear as well as the relationship between society, politics, culture, and modern history of Japan and international political situation.

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Stimulation of Blood Flow Needs a Parallel Magnetic Field and Psycho-physics acupuncture

  • Oh, Hung-Kuk
    • 한국감성과학회:학술대회논문집
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    • 한국감성과학회 2000년도 추계학술대회 논문집
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    • pp.105-112
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    • 2000
  • The conventional model did not take momentum conservation into consideration when the electron absorbs and emits the photons. II-ray provides momentum conservations on any directions of the entering photons, and also the electrons have radial momentum conservations and fully elastic bouncing between two atoms, in the new atom model. Conventional atom model must be criticized on the following four points. (1) Natural motions between positive and negative entities are not circular motions but linear going and returning ones, fur examples sexual motion, tidal motion, day and night etc. Because the radius of hydrogen atom's electron orbit is the order of 10$^{-11}$ m and the radia of the nucleons in the nucleus are the order of 10$^{-l4}$m and then the converging $\pi$-gamma rays to the nucleus have so great circular momentum, the electron can not have a circular motion. We can say without doubt that any elementary mass particle can have only linear motion, because of the $\pi$-rays' hindrances, near the nucleus. (2) Potential energy generation was neglected when electron changes its orbit from outer one to inner one. The h v is the kinetic energy of the photo-electron. The total energy difference between orbits comprises kinetic and potential energies. (3) The structure of the space must be taken into consideration because the properties of the electron do not change during the transition from outer orbit to inner one even though it produces photon. (4) Total energy conservation law applies to the energy flow between mind and matter because we daily experiences a interconnection between mind and body. Any magnet absorbs n-rays to S pole and sends out the $\pi$-rays from N pole. Proton are constructed with the closed n-rays quantum-mechanically. The crystallizing n-bonding makes two $\pi$-far infrared rays of one wave length between two protons if two $\pi$-rays are supplied to each proton. It is easily done for a $\pi$-ray to be absorbed to a proton if there is a parallel magnetic flow to the blood flow because a $\pi$-ray advances axially under a magnetic field and a proton looks like a sphere. A axially advancing disk-like $\pi$-ray can meet more easily the coming spheres than from the other directions. The blood crystals stimulate the autonomous nerves on the blood vessels during the flow by their mechanical sliding collisions. SM n-ray meridian therapy and SMACN $\pi$-ray meridian therapy show the stimulation of blood flow and also combinational experiment between SM $\pi$-ray meridian therapy and n-ray psycho-physics acupuncture shows more clearly that magnet is forcing to make $\pi$-rays absorbed to the nucleons.s.ons.

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A Critical Note on the Electric Field in Direct and Alternating Current and Its Consciousness

  • Oh, Hung-Kuk
    • 한국감성과학회:학술대회논문집
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    • 한국감성과학회 2000년도 추계학술대회 논문집
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    • pp.98-104
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    • 2000
  • The conventional model did not take momentum conservation into consideration when the electron absorbs and emits the photons. II-ray provides momentum conservations on any directions of the entering photons, and also the electrons have radial momentum conservations and fully elastic bouncing between two atoms, in the new atom model. Conventional atom model must be criticized on the following four points. (1) Natural motions between positive and negative entities are not circular motions but linear going and returning ones, for examples sexual motion, tidal motion, day and night etc. Because the radius of hydrogen atom's electron orbit is the order of 10$^{-11}$ m and the radia of the nucleons in the nucleus are the order of 10$^{-14}$ m and then the converging $\pi$-gamma rays to the nucleus have so great circular momentum, the electron can not have a circular motion. We can say without doubt that any elementary mass particle can have only linear motion, because of the $\pi$-rays'hindrances, nearthenucleus. (2) Potential energy generation was neglected when electron changes its orbit from outer one to inner one. The h v is the kinetic energy of the photo-electron. The total energy difference between orbits comprises kinetic and potential energies. (3) The structure of the space must be taken into consideration because the properties of the electron do not change during the transition from outer orbit to inner one even though it produces photon. (4) Total energy conservation law applies to the energy flow between mind and matter because we daily experiences a interconnection between mind and body. Conventional Concept of Electric Field must be extended in the case of the direct and alternating current. Conventional concept is based on coulomb's force while the electric potential in the direct and alternating current is from Gibb's free energy. And also conventional concept has not any consciousness with human being but the latters has a conscious sensibility. The cell emf is from the kinetic energy of the open $\pi$-rays flow through the conducting wire. The electric potential in alternating current is from that the trans-orbital moving of the induced change of magnetic field in the wire produces flows of open $\pi$-rays, which push the rotating electrons on the orbital and then make the current flow. Human consciousness can induce a resonance with the sensibility of the open $\pi$-rays in the electric measuring equipment. Specially treated acupunctures with Nasucon is for sending an acupunctural effect from one place to another via space by someone's will power.

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약용식물 유래 정유성분 분석 및 산화 스트레스로부터 PC12 신경세포 보호 효과 (Chemical Composition and Protective Effect of Essential Oils Derived from Medicinal Plant on PC12 Neuro-cells Induced by Oxidative Stress)

  • 이지연;박정용;김동휘;최수지;장귀영;서경혜
    • 한국식품영양학회지
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    • 제33권2호
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    • pp.215-221
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    • 2020
  • The purpose of this study was to investigate the protective effect on oxidative stress induced PC12 cells, and volatile flavor composition of essential oils derived from medicinal plant seeds- Gossypium hirsutum L. (G. hirsutum), Coix lachryma-jobi (C. lachryma-jobi) and Oenothera biennis (O. biennis). The essential oils were obtained by the solvent (hexane) extraction method from the seeds. The essential oils of the seeds were analyzed by the solid-phase micro-extraction gas chromatography mass spectrometry (SPME-GC/MS). The major compounds of G. hirsutum, C. lachryma-jobi and O. biennis were cyclonexanol (16.65%), β-asarone (14.29%) and ylangene (50.01%). The DPPH radical scavenging activity (IC50) was the highest value of 8.52 mg/mL in the O. biennis. Additionally, IC50 values of G. hirsutum and C. lachryma-jobi were 26.76 mg/mL and 36.81 mg/mL. For the oxidative stress on PC12 cells, we treated with hydrogen peroxide (H2O2). The pretreatment of oxidative stress induced PC12 cells with all the essential oils preserved or increased their cell viability and G. hirsutum and O. biennis attenuated the ROS generation (by 68.75% and 56.25% vs. H2O2 control). The results of this study suggest that the essential oils derived from medicinal plant seeds could be used as valuable back data as a natural essential oil material to prevent neurodegenerative diseases by protecting neuro-cells.

Process Optimization of PECVD SiO2 Thin Film Using SiH4/O2 Gas Mixture

  • Ha, Tae-Min;Son, Seung-Nam;Lee, Jun-Yong;Hong, Sang-Jeen
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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    • pp.434-435
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    • 2012
  • Plasma enhanced chemical vapor deposition (PECVD) silicon dioxide thin films have many applications in semiconductor manufacturing such as inter-level dielectric and gate dielectric metal oxide semiconductor field effect transistors (MOSFETs). Fundamental chemical reaction for the formation of SiO2 includes SiH4 and O2, but mixture of SiH4 and N2O is preferable because of lower hydrogen concentration in the deposited film [1]. It is also known that binding energy of N-N is higher than that of N-O, so the particle generation by molecular reaction can be reduced by reducing reactive nitrogen during the deposition process. However, nitrous oxide (N2O) gives rise to nitric oxide (NO) on reaction with oxygen atoms, which in turn reacts with ozone. NO became a greenhouse gas which is naturally occurred regulating of stratospheric ozone. In fact, it takes global warming effect about 300 times higher than carbon dioxide (CO2). Industries regard that N2O is inevitable for their device fabrication; however, it is worthwhile to develop a marginable nitrous oxide free process for university lab classes considering educational and environmental purpose. In this paper, we developed environmental friendly and material cost efficient SiO2 deposition process by substituting N2O with O2 targeting university hands-on laboratory course. Experiment was performed by two level statistical design of experiment (DOE) with three process parameters including RF power, susceptor temperature, and oxygen gas flow. Responses of interests to optimize the process were deposition rate, film uniformity, surface roughness, and electrical dielectric property. We observed some power like particle formation on wafer in some experiment, and we postulate that the thermal and electrical energy to dissociate gas molecule was relatively lower than other runs. However, we were able to find a marginable process region with less than 3% uniformity requirement in our process optimization goal. Surface roughness measured by atomic force microscopy (AFM) presented some evidence of the agglomeration of silane related particles, and the result was still satisfactory for the purpose of this research. This newly developed SiO2 deposition process is currently under verification with repeated experimental run on 4 inches wafer, and it will be adopted to Semiconductor Material and Process course offered in the Department of Electronic Engineering at Myongji University from spring semester in 2012.

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알칼리 붕소 수소화물 용액에서 수소발생을 위한 촉매에 관한 연구 (A Study of Catalysts for Hydrogen Generation from Alkali Borohydride Solution)

  • 정성욱;조은애;오인환;김성현;남석우
    • 한국에너지공학회:학술대회논문집
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    • 한국에너지공학회 2004년도 춘계 학술발표회 논문집
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    • pp.119-124
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    • 2004
  • 최근 소형 다기능, 고기능 전자장비의 개발로 인하여 고밀도 전원이 필요성이 대두되고 있다. 연료전지는 높은 전력 밀도를 가짐으로 인하여 소형 전원 장비에 가능성을 가지는 것으로 여겨지고 있다. 연료전지 중 특히 고분자 전해질 연료전지는 높은 전력밀도와 낮은 작동온도 등으로 인하여 이차전지의 자리를 대체할 수 있을 것으로 보여지지만 현재까지 연료 공급장치의 문제로 인하여 실용화되지 못하고 있다. 본 연구에서는 여러 가지 수소저장 물질 중에서 알칼리 붕소 수소화물을 이용하여 연료전지에 수소를 공급하고자 하며, 수소발생에 사용되는 촉매에 대한 연구를 진행하였다. 알칼리 붕소 수소화물의 수소발생 반응에 사용되는 촉매로는 Pt, Ru, Co, Ni 등이 사용되어질 수 있다. 이중에서 가장 수소발생 능력이 높은 촉매는 Ru이며, 비귀금속 촉매 중에는 Co가 높은 활성을 나타내었다. 본 연구에서는 Ru 촉매와 Co 촉매의 특성을 비교하였으며 연료전지에 수소를 공급할 수 있는 가능성을 확인하였다. Ru와 Co 촉매의 공통적인 특징은 알칼리 붕소화물인 NaBH$_4$의 농도가 높아질수록, 온도가 높아질수록 수소의 발생속도를 높이는 현상을 보였다. 또한 안정화제인 NaOH에 대하여, Ru의 경우는 농도가 높아질수록 수소발생 속도가 낮아졌으며, Co는 그 반대의 결과를 보였다. NaBH$_4$의 분해 반응으로 발생된 수소를 연료전지에 공급하여 2W급의 휴대폰용 연료전지를 구동할 수 있었다. 이로써 알칼리 붕소수소화물로부터 발생된 수소를 이용하여 안정적으로 연료전지를 구동할 수 있는 가능성을 확인하였다. 유류 분해정도를 파악하는 지시자로써 특정 무기 오염물질을 이용할 수 있을 가능성이 있으므로 좀더 이들 관계성에 대한 연구가 진행될 필요성이 있다고 판단된다.고 과학적으로 분석할 수 있는 방법이 될 수 있을 것으로 기대된다. 의미를 되새기는 것으로 짧은 연구를 시작하겠다. 등은 활성 값이 70% 이상으로 퇴적물 독성이 상대적으로 낮았다. 이중나선 DNA 함량은 28.4 % - 49%로 대조군에 비해서 감소가 크다. 대부분의 정점이 대조군의 30% 내외로 정점 간의 차이는 크지는 않다. 그러나 다른 측정자료와 같이 정점 22에서 18%로 최소치를 나타내고, 정점 2, 12에서 20% 내외의 값을 보인다. 종합적으로 볼 때 오염물질의 유입이 크고, 광양제철 인근 정점 들이 모두 다른 정점에 비해서 낮아서, 퇴적물 독성이 높은 정점으로 조사되었다.hiwo의 광합성 능력은 낮은 농도들에서는 대조구와 유사하였으나, 5 $\mu\textrm{g}$/l의 높은 농도에서는 초기에 매우 낮은 광합성 능력을 보이다가 시간이 경과하면서 대조군보다 더 높은 경향을 나타냈다. 이러한 결과는 식물플랑크톤이 benso[a]pyrene의 낮은 농도에서 노출될 때는 이 물질을 탄소원으로 사용할 가능성이 있음을 시사한다. 본 연구의 결과들은 연안해역에 benso[a]pyrene과 같은 지속성 유기오염물질이 유입되었을 때 내정여부에 따라 식물플랑크톤 군집내 종 천이와 일차생산력에 크게 영향을 미칠 수 있음을 시사한다.TEX>5.2개)였으며, 등급별 회수율은 각각 GI(8.5%), GII(13.4%), GIII(43.9%), GIV(34.2%)로 나타

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Numerical Simulation of Cavitating Flows on a Foil by Using Bubble Size Distribution Model

  • Ito, Yutaka;Nagasaki, Takao
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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    • pp.216-227
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    • 2004
  • A new cavitating model by using bubble size distribution based on bubbles-mass has been proposed. Both liquid and vapor phases are treated with Eulerian framework as a mixture containing minute cavitating bubbles. In addition vapor phase consists of various sizes of vapor bubbles, which are distributed to classes based on their mass. The bubble number-density for each class was solved by considering the change of the bubble-mass due to phase change as well as generation of new bubbles due to heterogeneous nucleation. In this method, the bubble-mass is treated as an independent variable, and the other dependent variables are solved in spatial coordinates and bubble-mass coordinate. Firstly, we employed this method to calculate bubble nucleation and growth in stationary super-heated liquid nitrogen, and bubble collapse in stationary sub-cooled one. In the case of bubble growth in super-heated liquid, bubble number-density of the smallest class based on its mass is increased due to the nucleation. These new bubbles grow with time, and the bubbles shift to larger class. Therefore void fraction of each class is increased due to the growth in the whole class. On the other hand, in the case of bubble collapse in sub-cooled liquid, the existing bubbles are contracted, and then they shift to smaller class. It finally becomes extinct at the smallest one. Secondly, the present method is applied to a cavitating flow around NACA00l5 foil. Liquid nitrogen and liquid oxygen are employed as working fluids. Cavitation number, $\sigma$, is fixed at 0.15, inlet velocities are changed at 5, 10, 20 and 50m/s. Inlet temperatures are 90K in case of liquid nitrogen, and 90K and 1l0K in case of liquid oxygen. 110K of oxygen is corresponding to the 90K of nitrogen because of the same relative temperature to the critical one, $T_{r}$=$T/T_c^{+}$. Cavitating flow around the NACA0015 foils was properly analyzed by using bubble size distribution. Finally, the method is applied to a cavitating flow in an inducer of the LE-7A hydrogen turbo-pump. This inducer has 3 spiral foils. However, for simplicity, 2D calculation was carried out in an unrolled channel at 0.9R cross-section. The channel moves against the fluid at a peripheral velocity corresponding to the inducer revolutions. Total inlet pressure, $Pt_{in}$, is set at l00KPa, because cavitation is not generated at a design point, $Pt_{in}$=260KPa. The bubbles occur upstream of the foils and collapse between them. Cavitating flow in the inducer was successfully predicted by using the bubble size distribution.

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RAW 264.7 대식세포에서 쑥부쟁이 추출물의 항산화 및 항염증 효능에 관한 연구 (Antioxidant and Anti-inflammatory Effects of Ethanol Extract of Aster yomena in RAW 264.7 Macrophages)

  • 김성옥;정지숙;최영현
    • 생명과학회지
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    • 제29권9호
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    • pp.977-985
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    • 2019
  • 쑥부쟁이는 국화과에 속하는 다년생 식물로서 다양한 질병의 예방 및 치료에 오랫동안 사용되어 왔다. 최근 연구에서 쑥부쟁이 잎 추출물이 항산화 및 항염증 효과가 있는 것으로 알려져 있지만, 정확한 효능 평가에 관한 연구는 여전히 미비한 실정이다. 본 연구에서는 RAW 264.7 대식세포에서 쑥부쟁이 잎 에탄올 추출물(EEAY)의 항산화 효능이 항염증 효능과 연관이 있는지의 여부를 조사하였다. 본 연구의 결과에 의하면, EEAY는 $H_2O_2$ 처리에 의한 RAW 264.7 세포의 세포 독성을 유의적으로 억제시켰으며, 이는 Nrf2 및 HO-1의 발현 증가와 관련이 있음을 보여 주었다. 또한 EEAY는 $H_2O_2$에 의한 apoptosis를 유의적으로 억제하였으며, 이는 caspase-3의 활성 억제에 따른 PARP의 분해 차단과 연관성이 있었다. 그리고 EEAY는 대표적인 항 염증성 사이토카인인 IL-10의 발현 및 생산을 증가시켰으며, 이는 전사 및 번역 수준에서의 TLR-4 및 Myd88 발현 증가와 관련이 있었다. 아울러 EEAY는 LPS에 의한 염증성 매개인자인 NO의 생성 증가를 현저히 억제하였으며, EEAY에 의한 NO 생성의 억제 효과는 HO-1 유도제인 hemin에 의해 더욱 증가되었다. 따라서 본 연구의 결과는 EEAY에 의한 산화적 및 염증성 스트레스에 대한 RAW 264.7 대식세포의 보호 효과에 최소한 Nrf2/HO-1 신호 경로의 활성화가 관여할 가능성을 보여주었다.