• 제목/요약/키워드: Barrier system

검색결과 1,239건 처리시간 0.024초

한국(韓國) 동해대륙단(東海大陸端) 해저지질(海底地質) (Submarine Geology of Continental Margin of the East Sea, Korea)

  • 김종수
    • 자원환경지질
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    • 제15권2호
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    • pp.65-88
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    • 1982
  • In the last ten years, marine geological and geophysical survey and research were conducted by Japanese, Russian and American scientists in the East Sea of Korea (Japan Sea). Many research results were published. However, regional research of the geology of the continental margin of the Korean Peninsula was not conducted. This study has made on attempt to classify submarine strata and stratigraphic boundaries. The study has revealed characters of submarine geology and structure. Isopach maps of each identified stratigraphic unit have been constructed as the results of this study. The study was conducted on the basis of analyses of marine seismic surveys carried out in the continental margin of the East Sea between Kangneung and Pohang. Three depositional basins were identified in the study area and they were named as, Mukho Basin, Hupo Basin and Pohang Basin. The Mukho Basin is developed in continental slope and shelf in the area between Kangneung and Samcheog. Quaternary and Pliocene sediments attain a maximum thickness of 900 m. Basement rocks are interpreted as granite and gneiss. They are correlated with granite-gneiss of the Taebaecksan Series of Pre-cambrian age and the Daebo granite of Jurassic age. The Hupo Basin is developed in the continental shelf between Uljin and Youngdeok. Quaternary and Pliocene sediments attain a maximum thickness of 600 m. Basement rocks were interpreted as granite and gneiss and they are correlated with metamorphic rocks of Pre-cambrian age and the Daebo granites, comprising the Ryongnam Massif. The Pohang Basin is developed in the area between Pohang and Gangu. This basin contains Miocene and older sediments. Basement rocks are not shown. Many faults are developed within the continental shelf and slope. These faults strike parallel with the coast line. A north-south direction is predominant in the southern study area. However, in the northern study area the faults strike north, and north-west. The faults are parallel to each other and are step faults down-thrown to the east or west, forming horst and graben structures which develop into sedimentary basins. Such faults caused the development of submarine banks along the boundary between the continental shelf and slope. This bank has acted as a barrier for deposition in the Hupo Basin. Paleozoic sedimentary rocks distributed widely in the adjacent land area are absent in the Mukho Basin. This suggests that the area of the basin was situated above the sea level until the Pliocene time. The study area contains Pliocene sediments in general. These sediments overlie the basement complex composed of metamorphic rocks, granites, Cretaceous (Kyongsang System) sedimentary rocks and Miocene sedimentary rocks. These facts lead to a conclusion that the continental shelf and slope of the study area were developed as a result of displacements along faults oriented parallel to the present coast line in the post Miocene time.

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중학생의 청소년활동 참여와 진로결정의 관계에서의 학업성취수준의 매개효과에 관한 연구 (A Study on Relationship of Career Decision-Making and Youth Activities : Focused on Mediating Effect of Academic Achievement Level)

  • 은선경
    • 한국산학기술학회논문지
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    • 제21권6호
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    • pp.611-617
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    • 2020
  • 본 연구의 목적은 중학생들의 진로결정에 영향을 미치는 청소년활동 참여와 학업성취의 관계를 파악하고자 함에 있다. 이를 위해 본 연구는 한국청소년정책연구원의 2018 한국아동·청소년 패널자료를 활용하였다. 중학교 1학년 2,471명의 자료를 활용하여 회귀분석을 통한 매개효과 분석을 실시하였다. 본 연구의 결과, 청소년활동 참여와 진로결정의 관계에서 학업성취 수준은 부분 매개효과가 있는 것으로 나타났다. 즉, 청소년활동 참여는 진로결정에 직접적인 영향을 미치기도 하지만, 학업성취수준에 영향을 미치고 학업성취수준이 진로결정에 영향을 미친다. 중학생들의 청소년활동 참여 강화는 학업성취 수준을 향상시킬 수 있고, 긍정적 학업성취의 경험이 진로결정에 긍정적으로 작용할 수 있음을 발견하였다. 따라서 자유학기제를 통해 중학생들로 하여금 다양한 청소년활동 프로그램에 참여할 수 있도록 프로그램의 연구 및 개발과 환경조성이 이루어져야 할 것이다. 따라서 다양한 청소년활동 프로그램의 참여가 학업성취에 대한 동기부여로 작용할 수 있도록 청소년의 관심과 욕구에 반응하는 활동 프로그램의 개발과 운영이 이루어져야 함과 동시에, 다양한 청소년활동 프로그램이 자유학기제와 연계되어 프로그램 참여를 확대 강화할 수 있도록 청소년지도자와 교사들에게 교육과 연수를 제공하는 것이 필요하다.

Evaluation of Cumulative and Conditional Antibiotic Release from Vancomycin-Embedded Fibrin Sealant and Its Antibacterial Activity : An In Vitro Study

  • Shin, Dong-Won;Sohn, Moon-Jun;Cho, Chong-Rae;Koo, Hae-won;Yoon, Sang Won
    • Journal of Korean Neurosurgical Society
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    • 제63권1호
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    • pp.45-55
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    • 2020
  • Objective : Fibrin sealants have been used for hemostasis, sealant for cerebrospinal fluid leakage, and adhesive barrier in neurosurgery. Further, as its clinical use and role of an effective drug delivery vehicle have been proposed. This study was performed to measure antibacterial activity and continuous local antibiotic release from different concentrations of vancomycin-impregnated fibrin sealant in vitro. Methods : Antibacterial activity was investigated by disk diffusion test by measuring the diameter of the growth inhibition zone of bacteria (methicillin-resistant Staphylococcus aureus, ATCC29213) from vancomycin-embedded fibrin sealant disc diluted at five different concentrations (C1-C5; 8.33, 4.167, 0.83, 0.083, and 0.0083 mg/disc, respectively). Continuous and conditioned release of vancomycin concentration (for 2 weeks and for 5 days, respectively) were also measured using high-performance liquid chromatography (HPLC) method. To mimic the physiologic wound conditions with in vitro, conditioned vancomycin release in phosphate buffer solution (PBS) was measured and replaced PBS for five consecutive days, half a day or completely daily. Results : In the disk diffusion test, the mean diameters of bacterial inhibition zone were 2.54±0.07 cm, 2.61±0.12 cm, and 2.13±0.15 cm (C1, C2, and C3 respectively) but 1.67±0.06 cm and 1.23±0.15 cm in C4 and C5, respectively. Continuous elution test elicited the peak release of vancomycin from the fibrin sealant at 48 hours, with continued release until 2 weeks. However, conditioned vancomycin release decreased to half or more on day 2, however, the sustainable release was measured over the therapeutic dose (10-20 ㎍/mL) for 5 days and 4 days in assays of half and total exchange of PBS. Conclusion : This study suggests that fibrin sealant can provide an efficient vehicle for antibiotic drug release in a wide range of neurosurgical procedures and the safe and effective therapeutic dose will be at the concentration embedded of 4.167 mg/disc or more of vancomycin.

에틸렌 처리를 위한 충진층 유전체배리어방전 플라즈마 반응기의 특성 (Characteristics of Packed-bed Plasma Reactor with Dielectric Barrier Discharge for Treating)

  • M. S. P. 수다카란;조진오;트린 쿠앙 흥;목영선
    • 공업화학
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    • 제26권4호
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    • pp.495-504
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    • 2015
  • 본 연구에서는 충진층 플라즈마 반응기의 특성 및 에틸렌을 분해하는데 있어서 플라즈마 반응기의 직렬 및 병렬 배열에 따른 영향에 대해 조사하였다. 플라즈마 방전 개시 전의 반응기 유효 커패시턴스는 ${\gamma}$-알루미나 펠릿이 충진된 경우가 충진되지 않은 경우보다 컸으나, 일단 플라즈마 방전이 개시되고 나면 ${\gamma}$-알루미나 충진 여부와 관계없이 유효 커패시턴스가 유사하였다. 플라즈마 상태에서 생성되는 전자의 에너지는 전기장세기에 크게 의존하며, 0~20%(v/v) 범위의 산소농도(질소 : 80~100% (v/v))에서는 기체조성에 크게 영향을 받지 않는 것으로 나타났다. 플라즈마 상태에서 생성되는 여러 활성 성분들 중 바닥상태의 산소원자 및 오존이 산화 반응에 주로 관여하며, 전기장세기가 높아질수록 산소원자가 상대적으로 감소하는 대신 질소원자의 분율이 급격히 증가한다. 플라즈마 공정에서 전압, 방전 전력, 기체 유량, 체류시간 등 반응기의 성능에 영향을 주는 여러 가지 파라미터들이 있지만, 모든 파라미터들이 비에너지밀도 하나로 통합될 수 있음을 확인하였으며, 직렬 및 병렬로 연결된 반응기의 성능도 비에너지밀도만의 함수로 간주할 수 있으므로 반응기 설계 과정이 크게 단순화될 수 있다. 비에너지밀도의 함수로 나타낸 반응속도상수를 이용하여 계산한 결과도 실험데이터를 잘 예측할 수 있었다.

Ecological Functions and Losses of Traditional Korean Village Groves

  • Lee, D.-W.;Park, C.-R.
    • 한국제4기학회지
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    • 제18권2호통권23호
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    • pp.65-66
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    • 2004
  • There have been groves, in many cases, along with hedgerows and remnant forests around a traditional Korean village. A village grove is very closely connected to the life of residents. Sometimes it was a holy place where important village festivals were held, and became a resting place for farmers, especially in sunny summer. As a matter of fact, it is noted that traditional Korean village groves had been fostered for many purpose as religion, Confucianism, scenery, sanitation, traffic guard, public security, agriculture, hunting, and military and public uses were included in Chosun Govemor General(1938). Village groves were usually located at the outlet of watershed inside which a village was built. In addition, village groves used to be established along part of mountain ranges, streams and streets. A unique type of village grove, called bibosoop was fostered especially where the outlet of watershed was largely opened. In other cases, it was placed where a part of mountain range was relatively low, or where village residents were likely to see ugly objects such as a huge cliff, stony upland with an unvegetated area and the like(Kim and Jang 1994). In a sense, a sheltebelt is a sort of bibosoop as it is a landscape element to complement places that are exposed to strong winds. However, it is comparable to other typical bibosoop that is situated at a topographically very specific zone of watershed. In this paper, we will address potential functions of Korean village groves from a perspective of modern landscape ecology and show current status of some remnants, based on preliminary surveys. A village grove functions as barrier or filter of objects such as water, nutrients, and other elements and habitat of wildlife (park et al. 2003, Lee 2004). The village grove slows down the flow of water and air, maintains soil moisture an hinders soil erosion, enabling cultivation of crops and bringing up creatures nearby. It contributes to enhancing biodiversity. Birds rest on shrubby and woody trees of the element. Presumably, other organisms may also inhabit the village groves and take advantage of it when those move from a forest patch to others. Emerging insects acclimate themselves in the shade of the green space before they fly to sunny air. Besides the village grove acts as a component of agroforestry system as leaf litter is shed from a grove to an asjacent agricultural area, and transformed into green manure(Lee 2004). By the way, many of the landscape elements were destroyed or declined in Koea during the past several decades. The losses have been parallel or linked to environmental degradation. Unfortunately, we have a little reliable data as for how many groves have disappeared in Korea until now. There has been no complete census on the village groves in Korea, and the viewpoints of survey were to a degree different depending on surveyors. So, it is difficult to analyze the temporal and spatial change of village groves. Currently, national inventory data of Korean village groves are available in three reports. We reviewed the locations of village groves and arranged those according to the present administrative units, DONG. With the limited data, we found that at least 484 of village groves were recorded in South Korea. Among all provinces, village groves were most in Gyeongsanbuk-Do Province and least in Chungcheongbuk-Do Province(Table 1). This is a preliminary report prepared while some quantitative data regarding functions and lossers of the village groves are being collected. More detailed data will be introduced in the near future.

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소규모 사업장 산업보건인력의 업무수행 분석 (Facilitating Factors of and Barriers to Performance Improvement of Small Scale Enterprise Occupational Health Personnel in Korea)

  • 전경자;백도명;김은희;김지용;하은희;김선민;박혜숙;정혜선
    • 한국직업건강간호학회지
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    • 제6권2호
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    • pp.156-167
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    • 1997
  • In Korea, based on the Revised Law of Occupational Safety and Health a new entity of institution was set up in 1990 to provide occupational health services to SSE in which three sorts of personnel as a team have to be involved. These institutions, in charge of scores to hundreds of workplace area-wide, have been providing occupational health services without payment from employers or employees, and government reimburses through the Occupational Injury Prevention Insurance since 1993. As a service provider, a team is composed of doctors, nurses and industrial hygienists. Undergraduate and postgraduate educations for the SSE occupational health are not specified and the question on the performance of the personnel has been raised. This study was designed to analyze the facilitating factors of and barriers to the performance and its improvement of these personnel. In 1997, the survey was conducted with all 58 institutions. Structured questionnaires were mailed to 200 personnel who were providing the occupational health service for SSE. The response rate was 51.7% for doctors, 58.6% for nurses, and 60.3% for industrial hygienist, respectively. Results are as follows : 1) There is a guideline for occupational service mandated by the government. Under the guideline, the minimum frequency of visiting workplace is assured with six times of doctors, 17 times for nurse and industrial hygienist in a year. There are one doctor for every 200 factories, one nurse and one hygienist for every 100 factories. 2) All respondents have basic qualification for occupational health service. About 16.7%. of doctors are certified in industrial medicine or preventive medicine, and 64.7% of industrial hygienists had first grade certification. Totally 66.7% of personnel have been involved in occupational health for more than one year. 3) As a support system for the performance improvement, 66.3% respond that they have been provided with educational materials, advice related to industrial environment and guidance of MSDS from Korea Industrial Safety Corporation. Most respondents indicate the lack of concern of employers and employees as a main barrier to the improvement of the service. Also they are in the need of the training opportunity more focused on SSE. The Governments policy for SSE is a principal facilitating factor. Training program focused on SSE situation, manpower, technical support, etc. are areas to be improved to have a better occupational health service for SSE in Korea.

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온도 변화를 고려한 압축 벤토나이트 완충재의 수분흡입력 평가 (Evaluation of Water Suction for the Compacted Bentonite Buffer Considering Temperature Variation)

  • 윤석;고규현;이재완;김건영
    • 한국지반공학회논문집
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    • 제35권11호
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    • pp.7-14
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    • 2019
  • 압축 벤토나이트는 고준위폐기물을 처분하기 위한 공학적방벽 시스템에서 중요한 구성요소 중 하나인 완충재의 후보물질로 가장 적합한 것으로 고려되고 있다. 완충재는 처분공 내 사용후핵연료가 담긴 처분용기와 근계 암반 사이에 채워지는 방벽재로서 지하수 유입으로부터 처분용기를 보호하고, 방사성 핵종 유출을 저지한다. 처분 초기에는 처분용기로부터 발생하는 고온의 열량으로 인해 완충재의 포화도는 감소하지만, 그 후 주변 암반으로부터 유입되는 지하수로 인해 완충재의 포화도는 증가한다. 이렇듯 완충재는 처분 운영 조건에 따라 불포화에서 포화 상태로 도달하게 되기에 완충재의 불포화-포화 거동 특성은 공학적방벽의 전체 안전성을 좌우할 수 있는 중요한 입력자료이다. 따라서 본 연구에서는 국내 압축 벤토나이트 완충재에 대한 수분보유특성을 규명하고자 하였다. 처분 초기 온도 증가에 따라 완충재의 포화도가 감소하는 상황을 고려하여 상온에서부터 125도까지 압축 벤토나이트의 온도 증가에 따른 체적 함수비와 수분흡입력을 측정하였다. 또한 이를 상온에서 동일한 함수비에서의 수분보유능과 비교하였으며 상온에서의 수분흡입력은 1~15% 정도 크게 측정되었다.

유체가 채워진 착저신 유연막 구조물에 의한 파랑제어 (Wave Control by Bottom-Mounted and Fluid-Filled Flexible Membrane Structure)

  • 조일형;강창익
    • 한국해안해양공학회지
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    • 제12권3호
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    • pp.139-148
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    • 2000
  • 본 연구에서는 유체가 채워진 착저식 유연막 구조물과 파와의 상호작용 문제를 유탄성 이론을 사용하여 살펴보았다. 먼저 동역학적 문제를 풀기에 앞서 유체로 채워진 유연막 내부에 일정한 압력이 작용하였을 때, 유연막의 형상과 막에 작용하는 초기장력을 정역학문제를 풀어 구한다. 동역학적 문제를 풀기 위하여 유체영역을 내부영역과 외부영역으로 나누어, 내부영역을 유연막을 경계로 영역 1과 영역 2로 다시 나눈다. 내부영역에서는 경계요소법을 사용하여 파동장을 풀고, 외부영역에서는 고유함수전개법을 사용하여 해를 구한다. 두 영역이 만나는 정합면에서 이미 구한 해를 정합시켜 완전한 해를 구한다. 유연막의 거동은 원주 좌표계를 사용하여 유도된 선형화된 막방정식을 사용하여 이때 외력은 영역 1과 영역 2의 압력차로 주어지므로 영역 1과 영역 2의 해는 막방정식을 통하여 연성된다. 유체가 채워진 착저식 유연막 방파제의 성능에 미치는 중요한 변수로는 유연막의 형상(폭, 높이)과 유연막 내부압력, 유체의 밀도이다. 설계변수들을 바꿔가면서 유연막에 의한 파랑제어 효과를 투과율을 통하여 살펴보았다. 또한 파의 입사각도에 따른 파랑제어 효과를 함께 고찰하였다. 수치계산결과는 Ohyama의 실험결과와 비교하였고 두 결과는 정량적인 값 차이가 나지만 정성적으로 일치하고 있음을 확인하였다. 적절히 설계된 유연막은 소형어항 보호용이나 레저용 방파제로 활용할 수 있는 가능성을 발견하였다.

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흰쥐 해마 CA1 영역에서 H2O2에 의한 장기강화 억제에 대한 발효황금 추출물의 효과 (Effects of Fermented Scutellaria Baicalensis Extract on H2O2 - Induced Impairment of Long-term Potentiation in Hippocampal CA1 Area of Rats)

  • 허준호;;김민선
    • 동의생리병리학회지
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    • 제33권6호
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    • pp.356-362
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    • 2019
  • Scutellaria baicalensis (SB) has widely used in the treatment for various brain diseases in the field of Oriental medicine. Biofermantation of SB can make major chemical constituents of SB to pass blood-brain barrier easily and to have more potent anti-oxidant ability. There is a little information about the contribution of fermented SB (FSB) to the formation or maintenance of the neural plasticity in the hippocampus. The purpose of this study was to evaluate effects of FSB extract on hydrogen peroxide (H2O2) - induced impairments of the induction and maintenance of long-term potentiation (LTP), an electrophysiological marker for the neural plasticity in the hippocampus. From hippocampal slices of rats, the field excitatory postsynaptic potentials (fEPSPs) were evoked by the electrical stimulation to the Schaffer collaterals - commissural fibers in the CA1 areas and LTP by theta-burst stimulation by using 64 - channels in vitro multi-extracellular recording system. In order to induce oxidative stress to hippocampal slices two different concentrations (200, 400 μM) of H2O2 were given to the perfused aCSF before and after the LTP induction, respectively. The ethanol extract of FBS with concentration of 25 ㎍/ml, 50 ㎍/ml was diluted in perfused aCSF that had 200 μM H2O2, respectively. Oxidative stress by the treatment of H2O2 resulted in decrease of the induction rate of LTP in the CA1 area with a dose - dependent manner. However, the ethanol extract of FSB prevented the reduction of the induction rate of LTP caused by H2O2 - induced oxidative stress with a dose - dependent manner. These results may support a potential application of FSB to ameliorate impairments of hippocampal dependent neural plasticity or memory caused by oxidative stress.

조구등이 MCAO 모델 흰쥐에서 gliosis 억제에 미치는 영향 (The Effect of the Water Extract of Uncariae Ramulus et Uncus on Gliosis in the Middle Cerebral Artery Occlusion(MCAO) Rats)

  • 김상우;김선애;송봉근
    • 대한한방내과학회지
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    • 제31권4호
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    • pp.763-774
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    • 2010
  • Objectives : In condition of brain infarction, irreversible axon damage occurs in central nerve system(CNS), because gliosis becomes physical and mechanical barrier to axonal regeneration. Reactive gliosis induced by ischemic injury such as middle cerebral artery occlusion is involved with up-regulation of GFAP and CD81. The current study is to examine the effect of the Uncariae Ramulus et Uncus on CD81 and GFAP expression in the rat brain following middle cerebral artery occlusion. Methods : In order to study ischemic injuries on brain, infarction was induced by middle cerebral artery occlusion(MCAO) using insertion of a single nylon thread, through the internal carotid artery, into a middle cerebral artery. Cresyl violet staining, cerebral infarction size measurement, immunohistochemistry and microscopic examination were used to detect the expression of CD81 and GFAP and the effect on the infarct size and pyramidal cell death in the brain of the rat with cerebral infarction induced by MCAO. Results : The following results were obtained 1. Measuring the size of cerebral infartion induced by MCAO in the rat after injection of Uncariae Ramulus et Uncus showed the size was decreased. 2. Intravenous injection of Uncariae Ramulus et Uncus showed pyramidal cell death protection in the hippocampus in the MCAO rat. 3. Water extract injection of Uncariae Ramulus et Uncus decreased GFAP expression significantly in the MCAO rat. 4. Uncariae Ramulus et Uncus water extract decreased CD81 expression in the MCAO rat. 5. The administration of water extract of Uncariae Ramulus et Uncus induced up-regulation of c-Fos expression significantly compared with MCAO. 6. The admistration of water extract of Uncariae Ramulus et Uncus increased ERK expression significantly compared with MCAO. Conclusion : We observed that Uncariae Ramulus et Uncus could suppress the reactive gliosis, which disturbs the axonal regeneration in the brain of the rat with cerebral infaction after MCAO by controlling the expression of CD81 and GFAP. The effect may be modulated by the up-regulation of c-Fos and ERK. These results suggest that Uncariae Ramulus et Uncus can be a candidate to regenerate CNS injury.