• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.4
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• pp.213-218
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• 2002

The use of biological indicator for environmental monitoring has suddenly become popular in many international organizations as well as domestic ones. Since the biological indicator species should be well responsive to native environmental change, development of native indicator species is prerequisite for environmental assessment and restoration program. Through regression analysis of mean density and pH, potential indicator species were screened from Namsan and Kwangreung where differential environmental stresses are influenced; Lasiobelba remota, Ceratozetes sp. Tectocepheus velatus, Neogymnobates sp. and Oppia sp.3. Also keystone species in two study area were Lohmannia coreana, Ceratozetes sp., Rostrozetes pulcherrimus, and Lasiobelba remota in Namsan Deciduous forest and Neogymnobates sp., Neogymnobates donghaksaensis, and Cultroribula tridentata in Kwangreung. Advantages and disadvantages of using biological indicator for environmental monitoring were further discussed.

• The Journal of the Korea Contents Association
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• v.17 no.11
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• pp.541-553
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• 2017

Maker education rooted on Maker Movement refers to constructivist learning approach in which students as makers participate in producing visible outcomes through self-directed inquiry and creative hands-on activities in a real life context to solve their personal or social problems. The Maker education, therefore, stresses cultivation of 'maker mindset' in the process-oriented learning environments, pursuing evaluation aspects different from those in the existing educational system. In this context, this study aimed to explore an evaluation framework for the Maker education which reflects the Maker mindset: First, a literature review was conducted to search for the evaluation framework of the maker education which consists of the category of 5 ONs (Minds-on, Hands-on, Hearts-on, Social-on, Acts-on) representing intellectual, physical, emotional, interpersonal and practical aspects, respectively; Second, a Delphi survey for content validity was carried out to confirm the adequacy of the 5 ONs category along with sub-elements for each category. Finally, this study presented the evaluation framework for the Maker education, which is expected to be used as feedback rather than a measuring tool for the process and environments of the Maker education.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6679-6683
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• 2014

Background: Carcinoid crisis is a life-threating syndrome of neuroendocrine tumors (NETs) characterized by dramatic blood pressure fluctuation, arrhythmias, and bronchospasm. In the era of booming anti-tumor therapeutics, this has become more important since associated stresses can trigger carcinoid crisis. Somatostatin analogues (SSTA) have been recommended for prophylactic administration before intervention procedures for functioning NETs. However, the efficacy is still controversial. The aim of this article is to review efficacy of SSTA for preventing carcinoid crisis. Materials and Methods: PubMed, Cochrane Controlled trials Register, and EMBASE were searched using 'carcinoid crisis' as a search term combining terms with 'somatostatin'; 'octreotide'; 'lanreotide' and 'pasireotide' until December 2013. Results: Twenty-eight articles were retrieved with a total of fifty-three unique patients identified for carcinoid crisis. The most common primary sites of NETs were the small intestine and respiratory tract. The triggering factors for carcinoid crisis included anesthesia/surgery (63.5%), interventional therapy (11.5%), radionuclide therapy (9.6%), examination (7.7%), medication (3.8%), biopsy (2%) and spontaneous (2%). No randomized controlled trials (RCTs) were identified and two case-control studies were included to assess the efficacy of SSTA for preventing carcinoid crisis by meta-analysis. The overall pooled risk of perioperative carcinoid crisis was similar despite the prophylactic administration of SSTA (OR 0.44, 95% CI: 0.14 to 1.35, p=0.15). Conclusions: SSTA wasnot helpful for preventing carcinoid crisis based on a meta-analysis of retrospective studies. Attentive monitoring and careful intervention are essential. Future studies with better quality are needed to clarify any effect of SSTA for preventing carcinoid crisis.

• Current Research on Agriculture and Life Sciences
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• v.15
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• pp.93-100
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• 1997

Plants are exposed to wide range of different stresses. As plants have only limited mechanism for stress avoidance, they require flexible means for adaption to changing environmental conditions. This study was carried out to reasearch the changes of antioxidant enzymes activities as caused by water stress in four lettuceUactuca sativa) lines. Four lettuce lines exposed to water stress showed premature senescence as evidenced by the consistenent reduction in the content of total soluble protein and total lipid. Water stress also caused decreased activities of superoxide dismutase, catalase, ascorbate peroxidase, but decrease rates were different. Catalase activity was decreased much more than that of ascorbate peroxidase that suggest catalase reacted with hydrogenyperoxide directly not with ascorbate peroxidase.

• Korean Journal of Agricultural Science
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• v.41 no.2
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• pp.75-83
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• 2014

Recently, a quick drop of air temperature in plastic film houses by adverse weather conditions leads to the occurrence of low temperature damages to growing crops. Chilling injury, defined as a variety of growth restriction occurring below the optimal temperature, is one of environmental factors strongly affecting crop growth and yield. Low temperature causes the restricted evapotranspiration, reduced mineral uptake (P > K > $NO_3{^-}$), and an increase in electrolyte leakage such as K. Despite being different with plant species, an accumulation of soluble carbohydrates such as glucose, fructose, sucrose and starch under chilling condition is well known. A variety of environmental stresses are known to cause oxidative damage to plants either directly or indirectly by triggering an increased level of production of reactive oxygen species (ROS), and, to combat the oxidative damage, plants have the antioxidant defense systems comprising of enzymes, SOD, POD, CAT, GPX and APX, and non-enzymes, ascorbate, gluthathione, ${\alpha}$-tocopherol, phenolic compounds, carotenoid and flavonoids. The aim of this review is to provide basic information to build chilling-indicators and optimal nutrition management under adverse temperature conditions as broadly considering mineral uptake, carbohydrate metabolism and antioxidative defense system.

• Structural Engineering and Mechanics
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• v.5 no.5
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• pp.507-521
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• 1997

The ultimate behavior of a reinforced concrete hyperbolic paraboloid saddle shell under uniformly distributed vertical load is investigated using an inelastic, large displacement finite-element program originally developed at North Carolina State University. Unlike with the author's previous study which shows that the saddle shell possesses a tremendous capacity to redistribute the stresses, introducing tension stiffening in the model the cracks developed are no longer through cracks and formed as primarily bending cracks. Even though with small tension stiffening effect, the behavior of the shell is changed markedly from the one without tension stiffening effect. The load-deflection curves are straight and the slope of the curves is quite steep and remains unchanged with varying the tension stiffening parameters. The failure of the shell took place quite suddenly in a cantilever mode initiated by a formation of yield lines in a direction parallel to the support-to-support diagonal. The higher the tension stiffening parameters the higher is the ultimate load. The present study shows that the ultimate behavior of the shell primarily depends on the concrete tensile characteristics, such as tensile strength (before cracking) and the effective tension stiffening (after cracking). As the concrete characteristics would vary over the life of the shell, a degree of uncertainty is involved in deciding a specified ultimate strength of the saddle shell studied. By the present study, however, the overload factors based on ACI 318-95 are larger than unity for all the cases studied except that the tension stiffening parameter is weak by 3 with and without the large displacement effect, which shows that the Lin-Scordelis saddle shell studied here is at least safe.

• Journal of Aquaculture
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• v.18 no.3
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• pp.173-179
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• 2005

Superoxide dismutase (SOD), an antioxidant enzyme catalyzing the first step for scavenging the reactive oxygen species is important as an early warning indicator to address various biological stresses. For this reason, the monitoring the expressed pattern of SOD gene in fish organs is one of important biomarkers to assess the aquatic pollution caused by many toxic chemicals. Based on the Northern blot hybridization, semi-quantitative and/or realtime RT-PCRs, the alteration of SOD gene transcripts in shark liver was examined during the experimental acute exposures to cadmium. The expression of SOD at mRNA level was up-regulated both by injection (0, 0.5, 1 or 2 mg $CdCl_2/kg$ body weight for 48 hours) and by immersion (0 or $5{\mu}M$ Cd for 0, 1, 4 and 7 days) treatments of cadmium. The transcriptional stimulation of shark SOD gene by cadmium exposure was dependent upon doses and durations: there was a trend toward more increase in higher dose and longer durations of exposure. The hepatic SOD mRNA levels showed also a general agreement with the tissue cadmium concentrations accumulated in immersion exposure. This result may provide useful strategy to develop a fine molecular biomarker at mRNA level for detecting aquatic pollution caused by toxic metals.

• Journal of Family Resource Management and Policy Review
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• v.12 no.2
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• pp.57-72
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• 2008

The propose of this study is to examine the economic stresses and coping strategies for elderly households depending on the variables of background, and to analyze the relations between these factors. Elderly households which satisfied the following criteria were recruited for participation: (a) reside in Seoul, or in the metropolitan area (b) live apart from their adult children after retirement and (c) ages over sixty. From September 20th, 2006 to November 30th, 2006, 296 were used for this research. First, the mean score of the economic stress level of elderly households was 2.87 out of 5, and the stress levels of income expenditure and asset debt were intermediate. The mean score of the economic coping strategy was 3.17 out of 5. In order to overcome economic stress, elderly households utilized reducing their expenditure, financial management, and re-employment. The level of elderly households' life satisfaction was 3.29 of 5 and the depression was 3.17 of 5. Second, there was a difference in accordance with the objective economic variables and the degree of the economic stress after the review of the variables of the elderly households and the coping strategy due to economic stress. The result shows that the households which had a low economic status and high economic stress from the objective viewpoint participated in more economic activities. Their reactions were to decrease the overall expenditure through reducing the expenditure rather than to manage the asset effectively through re-employment or to inaugurating a business. Third, I analyzed situational factors, economic stress, and economic coping strategy in order to compare relative contributors to psychological well-being through using regression. At the third phase in the process of analysis, the socio-psychological factors appeared to be significant factors contributing to psychological well-being. Regarding the stress caused by income expenditure increased, when elderly households were more concerned about reducing expenditure and re-employment, their feelings of depression increased.

• Journal of Electrochemical Science and Technology
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• v.11 no.2
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• pp.132-139
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• 2020

Solid oxide fuel cells (SOFCs) are among one of the promising technologies for efficient and clean energy. SOFCs offer several advantages over other types of fuel cells under relatively high temperatures (600℃ to 800℃). However, the thermal behavior of SOFC stacks at high operating temperatures is a serious issue in SOFC development because it can be associated with detrimental thermal stresses on the life span of the stacks. The thermal behavior of SOFC stacks can be influenced by operating or material properties. Therefore, this work aims to investigate the effects of the thermal conductivity of each component (anode, cathode, and electrolyte) on the thermal behavior of samarium-doped ceria-based SOFCs at intermediate temperatures. Computational fluid dynamics is used to simulate SOFC operation at 600℃. The temperature distributions and gradients of a single cell at 0.7 V under different thermal conductivity values are analyzed and discussed to determine their relationship. Simulations reveal that the influence of thermal conductivity is more remarkable for the anode and electrolyte than for the cathode. Increasing the thermal conductivity of the anode by 50% results in a 23% drop in the maximum thermal gradients. The results for the electrolyte are subtle, with a ~67% reduction in thermal conductivity that only results in an 8% reduction in the maximum temperature gradient. The effect of thermal conductivity on temperature gradient is important because it can be used to predict thermal stress generation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.189-189
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• 2017

Salinity is one of the major abiotic stresses that severely affect crop production throughout the world; especially rice plant which is generally categorized as a typical glycophyte as it cannot grow in the presence of salinity. Phenotypic resistance of salinity is expressed as the ability to survive and grow in a salinity condition. Salinity resistance has, at least implicitly, been treated as a single trait. Physiological studies of rice suggest that a range of characteristics (such as low shoot sodium concentration, compartmentation of salt in older rather than younger leaves, high potassium concentration, high $K^+/Na^+$ ratio, high biomass and plant vigour) would increase the ability of the plant to cope with salinity. Criteria for evaluating and screening salinity tolerance in crop plants vary depending on the level and duration of salt stress and the plant developmental stage. Plant growth responses to salinity vary with plant life cycle; critical stages sensitive to salinity are germination, seedling establishment and flowering. We have established a standard protocol to evaluate large rice germplasms for overall performance based on specific physiological traits for salt tolerance at seedling stage. This protocol will help in identifying germplasms which can perform better in the presence of different salinity treatments based on single trait and also combination of different physiological traits. The salt tolerant germplasm can be taken forward into developing better varieties by conventional breeding and exploring genes for salt tolerance.