• Title/Summary/Keyword: Critical levels

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RF Compatibility Test Results of COMS satellite with Launch Vehicle (천리안위성의 발사체와의 전자파 적합성 시험결과 분석)

  • CHOI, Jae-Dong
    • Proceedings of the KIPE Conference
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    • 2010.11a
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    • pp.215-217
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    • 2010
  • This paper describes the test results of radiated compatibility with Ariane 5 launcher performed on the COMS Satellite test facility. Firstly, the Radiated Emission test results are analyzed in compliance with the Radiated Susceptibility requirement specification of Ariane 5 launcher. The satellite nominal operation is monitored during injection a radiated electric field corresponding to the launcher emissions levels in critical frequency ranges. And also, E-field are measured through a probe located at external units level in order to assess the EMC safety margin in Radiated mode.

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A novel potassium channel opener, KR-31378, protects cortex neurons from oxidative injury by restoring antioxidant enzyme activities and glutathione levels

  • Kim, Sun-Ok;Cho, In-Sun;Lee, Dong-Ha;Lim, Hong;Yoo, Sung-Eun
    • Proceedings of the PSK Conference
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    • 2003.04a
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    • pp.197.1-197.1
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    • 2003
  • Neuronal hyperexcitability followed by high level of intracellular calcium and oxidative stress play critical roles in neuronal cell death in stroke and neurotrauma. Hence, KR-31378, a novel benzopyran derivative was designed as a new therapeutic strategy for neuroprotection possessing both anti-oxidant and potassium channel modulating activities. In the present study, we tested for its neuroprotective efficacy against oxidative stress-induced cell death in primary cortical cultures and further investigated its neuroprotective mechanism. (omitted)

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Plastic Deformation Behavior of Ti-51.5at.%Ni Shape Memory Alloy Single Crystals (Ti-51.5at.%Ni 형상기억합금 단결정의 소성변형 거동)

  • Jun, Joong-Hwan;Sehitoglu, Huseyin
    • Journal of the Korean Society for Heat Treatment
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    • v.15 no.1
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    • pp.9-15
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    • 2002
  • Deformation behavior of nickel-rich Ti-51.5at.%Ni single crystals was investigated over a wide range of temperatures(77 to 440K) and strain levels(up to 9%) in compression. These alloys combined superior strength with wide range of pseudoelasticity temperature interval(~200K). The slip deformation in [001] orientation did not occur due to the prevailing slip system, and consequently, exhibited pseudoelastic deformation at temperatures ranging from 77 to 283K and 273 to 440K for the solutionized and over-aged cases, respectively. The critical transformation stress levels were in the range of 800 to 1800MPa for the solutionized case, and 200 to 1000MPa for the over-aged case depending on the temperature and specimen orientation. These stress levels are considerably higher compared to these class of alloys having lower Ni contents. The maximum transformation strains, measured from incremental straining experiments in compression, were lower compared to the phenomenological theory with Type II twinning. A compound twinning model depending on the successive austenite(B2) to intermediate phase(R) to martensite(B19') transformation predicts lower transformation strains compared to the Type II twinning case.

Altered Complexin Expression in Psychiatric and Neurological Disorders: Cause or Consequence?

  • Brose, Nils
    • Molecules and Cells
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    • v.25 no.1
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    • pp.7-19
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    • 2008
  • Complexins play a critical role in the control of fast synchronous neurotransmitter release. They operate by binding to trimeric SNARE complexes consisting of the vesicle protein Synaptobrevin and the plasma membrane proteins Syntaxin and SNAP-25, which are key executors of membrane fusion reactions. SNARE complex binding by Complexins is thought to stabilize and clamp the SNARE complex in a highly fusogenic state, thereby providing a pool of readily releasable synaptic vesicles that can be released quickly and synchronously in response to an action potential and the concomitant increase in intra-synaptic $Ca^{2+}$ levels. Genetic elimination of Complexins from mammalian neurons causes a strong reduction in evoked neurotransmitter release, and altered Complexin expression levels with consequent deficits in synaptic transmission were suggested to contribute to the etiology or pathogenesis of schizophrenia, Huntington's disease, depression, bipolar disorder, Parkinson's disease, Alzheimer's disease, traumatic brain injury, Wernicke's encephalopathy, and fetal alcohol syndrome. In the present review I provide a summary of available data on the role of altered Complexin expression in brain diseases. On aggregate, the available information indicates that altered Complexin expression levels are unlikely to have a causal role in the etiology of the disorders that they have been implicated in, but that they may contribute to the corresponding symptoms.

A Review of Scientific Evidence on Indoor Air of School Building: Pollutants, Sources, Health Effects and Management

  • Chithra, V.S;Shiva, Nagendra S.M
    • Asian Journal of Atmospheric Environment
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    • v.12 no.2
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    • pp.87-108
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    • 2018
  • Schools are one of the critical social infrastructures in a society, the first place for social activity and the most important indoor environment for children besides the home. Poor IAQ in classrooms can increase the chance of long-term and short-term health problems for students and staffs; affects productivity of teachers; and degrade the student learning environment and comfort levels. The primary objective of this paper is to review and summarize available scientific evidence on indoor air quality of schools and related health effects in children. It was found that the indoor air pollutant levels in school buildings varied over a wide range in different parts of the world depending on site characteristics, climatic conditions, outdoor pollution levels, occupant activities, ventilation type and building practices. Among the indoor air pollutants, particulate matter concentrations were found to be very high in many schools. Outdoor pollutant sources also play a major role in affecting the IAQ of the school building. Hence, scientific knowledge on sources of indoor pollutants, quantification of emissions, temporal and spatial dispersion of pollutants, toxicological properties, chemical and morphological characteristics of the pollutants and associated health risk among children in the school buildings are essential to evaluate the adequacy and cost effectiveness of control strategies for mitigating the IAQ issues.

Changes in Respiratory Metabolism and Blood Chemistry of Olive Flounder Paralichthys olivaceus Exposed to Hypoxia (저산소에 노출된 넙치(Paralichthys olivaceus)의 호흡대사와 혈액의 화학적 변화)

  • Han, Ji-Do;Kim, Heung-Yun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.1
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    • pp.45-52
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    • 2016
  • This experiment investigated changes in metabolic rate (MO2), critical oxygen saturation (Scrit), and blood chemistry of olive flounder Paralichthys olivaceus exposed to progressive hypoxia and returned to normoxic water at 20°C. The normoxic standard metabolic rate (SMR) and routine metabolic rate (RMR) were 69.5-83.9 and 70.2-156.4 mg O2 kg-1h-1, respectively based on fish weight. Scrit was 31.0% dissolved oxygen (DO) at 20°C. After returning the fish to 70% DO following exposure to hypoxia (20% DO), MO2 increased two-fold compared to the normoxic SMR and then decreased into the range of the RMR with time. Blood PO2 and plasma lactate decreased significantly after exposure to hypoxia (20% DO) and then increased as ambient oxygen saturation decreased. Cortisol levels increased as ambient oxygen saturation decreased, but the levels decreased rapidly in the range of the normoxic control when the fish were returned to ambient water with 70% DO. Plasma glucose levels increased when the fish were returned to normoxic water after exposure to a progressively more hypoxic condition.

Water Quality Monitoring for Hazard Analysis in Aquaculture Farm of Rainbow Trout (송어양식장의 위해요소 관리를 위한 수질 모니터링)

  • Kim, Young-Mog;Lee, Myung-Suk;Chung, Yong-Hyun
    • Journal of Fisheries and Marine Sciences Education
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    • v.25 no.4
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    • pp.819-827
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    • 2013
  • Water quality has been considered to be one of sanitation standard operating procedures (SSOP) for hazard analysis critical control points (HACCP) application in aquaculture farms. This study was conducted to evaluate a hazard caused by water used in aquaculture farm of rainbow trout. The water quality was analyzed to investigate both physiochemical and bacteriological level in water samples collected from aquaculture farm of rainbow trout, Oncorhynchus mykiss. No significant difference were observed on water temperature and pH from season to season. However, the levels of dissolved oxygen were decreased as the outside temperature was increased, even if the levels were adequate for aquaculture. Also, other physiochemical analysis including biochemical oxygen demand (BOD), chemical oxygen demand (COD) and suspended solid (SS) revealed that the waters for aquaculture analyzed in this study was suitable for rainbow trout aquaculture. The bacterial analyses were also revealed that the waters for aquaculture were met to both coliform group (<18 MPN/100mL) and viable cell count (<100 CFU/mL). However, some of waste waters from aquaculture farms showed higher levels of BOD and COD than those of waste water standard (<2 ppm), suggesting that regular cleaning of fish tank and precipitation tank is needed.

Analysis of Students' Reflective Journals on Medical Communication Role Plays (의료면담 역할극 사례의 학습자 성찰일지 분석)

  • Kim, Young Jon;Lee, Seung Hyun;Yoo, Hyo Hyun
    • Korean Medical Education Review
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    • v.19 no.3
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    • pp.169-174
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    • 2017
  • This study explores the phenomenon of learner reflection in writing. Sixty-nine reflection logs were submitted by students after medical interview role plays. Using thematic analysis methodology, the following three steps were carried out: (1) the entire contents of the logs were analyzed and coded, (2) the coded contents were reclassified and categorized into higher themes, and (3) all reflection logs were re-analyzed to derive the frequency according to their classifications. The learners' reflection contents were classified into 'preparation,' 'experience,' and 'future plan.' The levels of reflection were 'simple information and appreciation,' 'acquisition and application of knowledge,' and 'analysis and criticism.' The types of reflection were identified only at the level of 'analysis and criticism' and could be classified into 'relativization,' 'objectification,' and 'internalization.' Students' reflection levels were highest in the levels of 'acquisition and application of knowledge' (49.3%), and 'analysis and criticism' (37.7%). A total of 14.5% of the students showed 'internalization.' In order to enable internalized reflection at a critical level, instructional strategies to induce and promote reflection are needed.

The Impacts of Industrial Characteristics of Cities on Fine Dust Levels (도시의 산업특성이 미세먼지 농도에 미치는 영향)

  • Eum, Jeongin;Kim, Hyungkyoo
    • Journal of Environmental Science International
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    • v.29 no.5
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    • pp.445-455
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    • 2020
  • Fine dust is one of the most critical environmental issues in Korea, and the government recognizes the need to establish customized reduction policies based on regional characteristics. Several studies on air pollutants investigate whether factories affect the distribution of fine dust in a particular region. However, understanding the impact of the entire industry sector requires further investigation. This study identifies the impacts of industrial characteristics on fine dust levels of 141 municipalities across Korea in 2016. A total of 23 variables were used, of which 12 referred to industries and 11 to general characteristics of each city. Due to the high correlation between independent variables, partial least squares (PLS) regression models were used. The analysis identified 14 significant variables for PM10 and 13 for PM2.5. Therefore, the results suggest that local industrial characteristics can significantly influence fine dust levels and provide suggestions for establishing customized reduction policies based on local characteristics.

A Study on the Natural Park Plan through Ecological Conservation Value Evaluation -A Case Study on Mt. Hwangmaesan(Mt.) County Park - (생태적 보전가치 평가를 통한 자연공원 계획에 관한 연구 - 황매산 군립공원을 중심으로 -)

  • Shin, Ji-Hoon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.13 no.5
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    • pp.28-37
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    • 2010
  • This study is intend to evaluate natural conservation value, and to suggest natural park plan based on conservation value evaluation. In this study evaluation items are selected through related studies about ecological conservation evaluation, and evaluation items in this study can be classified into 2 aspects, ecological environment and topographic environment. After each evaluation items are overlaid with GIS program, management levels are derived from comprehensive overlaid maps of each evaluation items. Management areas can be classified into 5 levels; Critical Conservation Area, Conservation Area, Restoration Area, Passive Usable Area, Active Development Area and Settlement Area. So management areas can be matched each management levels to land use of natural park, that is district of preservation, district of natural environment, district of settlements and district of mass facilities. This study have good enough to evaluate ecological value for natural park plan, but, it is difficult to evaluate conservation value only with maps of each evaluation items, so it needs supplementary field survey for precise conservation value evaluation.