• Journal of Environmental Policy
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• v.7 no.4
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• pp.75-103
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• 2008

It is widely recognized that destruction of the eco-system with the counter-effect from the rapid industrialization threatens the life of human species. Furthermore, the extinction of some wild species keeps sending a warning message on the threat to human lives in the sense that both the human and wild lives have coexisted for a long time before the industrialization. Therefore, this study will shed a light on the importance of a natural ecology protection, focusing on wild-life conservation. This will provide an opportunity to consider the economic value of biodiversity through conservation of diverse wild lives and a natural ecology. Also, the irreversible damage to natural resources and extinction of certain species represent the urgency of this issue. This paper will perform a theoretical examination on the concept of wild plants and animals, an analysis of factors influencing their survivals, as well as the theory of natural ecology protections. This also examine the problems arising out of current domestic legislation of a natural ecology protection, comparing it with case studies of foreign countries. Through these analysis, this paper will seek for a maintenance of the currently enforcing natural ecology protection law to overcome its limits and will ultimately find alternatives to current system.

• Journal of Environmental Health Sciences
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• v.39 no.1
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• pp.48-55
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• 2013

Objective: The use of nanoparticle products is expected to present a potential harmful effect on consumers. Also, the lack of information regarding inhaled nanoparticles may pose a serious problem. In this study, we addressed this issue by studying pulmonary toxicity after nasal instillation of Al-NPs in SD rats. Methods: The animals were exposed to Al-NPs at 1 mg/kg body weight (low dose), 20 mg/kg body weight (medium dose) and 40 mg/kg body weight (high dose). To determine pulmonary toxicity, bronchoalveolar lavage (ts.AnBAL) fluid analysis and histopathological examination were conducted in rats. In addition, cell viability was investigated at 24 hours after the treatment with Al-NPs. Results: BAL fluid analysis showed that total cells (TC) count and total protein (TP) concentrations increased significantly in all treatment groups, approximately two to three times. Also, lactate dehydrogenase (LDH) and cytokines such as TNF-alpha and IL-6 dose-dependently increased following nasal instillation of Al-NPs. However, polymorphonuclear leukocytes (PMNs) levels showed no significant changes in a dose dependant manner in BAL fluid. In the cytotoxicity analysis, the treatment of Al-NPs significantly and dose-dependently induced cell viability loss (20 to 30%) and damage of cell membrane (5 to 10%) in rat normal lung epithelial cells (L2). Conclusions: Our results suggest that inhaled Al-NPs in the lungs may be removed quickly by alveolar macrophages with minimal inflammatory reaction, but Al-NPs have the potential to affect lung permeability. Therefore, extensive toxicity evaluations of Al-NPs are required prior to their practical application as consumer products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1286-1292
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• 2017

This study was conducted to investigate the hepatoprotective effects of 3,5-dicaffeoylquinic acid (3,5-DCQA) isolated from Ligularia fischeri against hydrogen peroxide-induced oxidative stress in HepG2 cells. Antioxidative effects of 3,5-DCQA were determined by measuring antioxidant enzyme [superoxide dismutase (SOD), catalase (CAT) glutathione peroxidase (GPx)] expression levels against hydrogen peroxide-induced oxidative stress using real-time PCR analysis. 3,5-DCQA treatment significantly increased gene expression levels of SOD, CAT, and GPx in a dose-dependent manner ($10{\sim}30{\mu}g/mL$) in HepG2 cells. Hepatoprotective effects were analyzed by measuring glutamic oxaloacetic transaminase (GOT), lactate dehydrogenase (LDH), and gamma-glutamyl transferase (GGT) activities using a biochemistry analyzer in hydrogen peroxide-treated HepG2 cells. 3,5-DCQA treatment significantly reduced GOT, LDH, and GGT activities in a dose-dependent manner ($10{\sim}30{\mu}g/mL$) against increased liver function index enzyme activities induced by hydrogen peroxide oxidative stress in HepG2 cells. The results reveal that 3,5-DCQA compound isolated from Ligularia fischeri can be useful for the development of an effective hepatoprotective agent.

• Journal of Biomedical Engineering Research
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• v.20 no.1
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• pp.37-44
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• 1999

Because of bone resorption, wear of ultra-high molecular weight polyethylene(UHMWPE) in total knee arthroplasty has been recognized as a major factor in long-term failure of knee implant. The surface damage and the following harmful wear debris of UHMWPE is largely related to contact stress. Most of the previous studies focused on the contact condition only at the articulating surface of UHMWPE. Recently, contact stress at the metal-backing interface has been implicated as one of major factors in UHMWPE wear. Therefore, the purpose of the is study is to investigate the effect of the contact stress for different thickness, conformity friction coefficient, and flexion degree of the UHMWPE component in total knee system, considering the contact conditions at both interfaces. In this study, a two-dimensional non-linear plane strain finite element model was developed. The results showed that the maximum value of von-Mises stress occurred below the articulating surface and the contact stress was lower for the more conforming models. All-polyethylene component showed lower stress distribution than the metal-backed component. With increased friction coefficient on the tibiofemoral contact surface, the maximum shear stress increased about twofold.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.380-385
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• 2009

The purpose of this study was to investigate the immunomodulatory effect of Ulva pertusa kjellman extract after undergoing a low temperature and high-pressure extraction process. First, the extracts obtained under the extraction conditions of 150 MPa and $80^{\circ}C$showed a relatively high antioxidant activity, with 90% super oxide radical activity compared to the extracts from conventional extraction process with water at $100^{\circ}C$. This extract also improved the growth of both human immune B and T cells up to $14.5{\times}10^4$ cells/mL and $14.2{\times}10^4$ cells/mL compared to $9.1{\times}10^4$ cells/mL in adding the extracts from conventional processes. It was found that the extracts obtained at 100 MPa and $60^{\circ}C$ showed better activities in NK cell growth and NO production from macrophage as $11.8{\times}10^2$ cells/mL and 30.0 ${\mu}M$. Overall, the extracts from high pressure and low temperature extraction process had relatively higher immune activation activity, possibly because the low temperature and high pressure extraction process may have higher yields of active compounds and have less damage to useful ingredients from relatively weak marine natural resources, such as Ulva pertusa kjellmann than that from the conventional extraction system.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.1
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• pp.45-50
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• 2009

By Laser Through-Silicon-Via process, debris and particles occur when you are forming. Therefore the research of TSV cleaning become important to remove those particles and debris. Both chemical cleaning method that uses a surfactant and physical cleaning method that uses a brush were studied with the via of $30{\mu}m$ diameter and $100{\mu}m$ depth on the 8 inch CMOS Image Sensor wafer. On the DI water and a surfactant in mixture ratio of 2:1, debris show $73{\mu}m^2$ per $0.054mm^2$. Cleaning is superior by lower mixture ratio of DI water and surfactant. In addition, It is less than 5% of debris distribution in the laser condition changed by Laser's frequency and its speed and cleaning had no effect. In the physical cleaning, there are no crack and damage when the system condition is set by $1000{\sim}3000rpm$ strip, $50{\sim}3000rpm$ rinsing, and $200{\sim}300rpm$ brushing Therefore, debris and particles can be removed by enforced chemical method and physical method.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.500-505
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• 2002

Many studies have shown that hyperglycemia leads to an increase of lipid peroxidation in diabetic patients and animals, reflecting a rise reactive oxygen species production. It is increasingly recognized that brain is another site of diabetic organ damage. Accordingly, this study was to investigate the effect of dandelion on oxygen free radical generating and scavenging system of brain in streptozotocin (STZ)-induced diabetic rats. Male Wistar rats were divided into diabetic (control) and diabetic-dandelion supplemented groups. Dandelion was supplemented for 4 weeks with dandelion leaf and root powder (DLP, DRP) or dandelion leaf and root water extract (DLW, DRW) based on 11.4 g of raw dandelion/kg diet. Diabetes was induced by single injection STZ (55 mg/kg B.W., i.p.)in a citrate buffer. Oxygen free radical generating enzymes, cytochrome P-450, amino-pyrine N-demethylase, aniline hydroxylase and xanthine oxidase, were lowered in dandelion supplemented-groups compared to the control group. Superoxide dismutase, catalase and gluthathione peroxidase activities of brain were also lower in dandelion leaf and root supplemented-group than in the control group, whereas glutathione S-transferase activity and gluthathione content were increased in dandelion supplemented-groups compared to the control group. With regard to the lipid peroxidation products, the malondialdehyde content of brain was lower in dandelion supplemented groups. Therefore, it could be suggested that powder and water extract of dandelion leaf or root are beneficial in preventing diabetic complication from lipid peroxidation and free radical in brain of diabetic rat brain.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.67-74
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• 2010

A variation of temperature acting on a RC roof slab causes a change of stress in concrete since it expands during summer and is compressed during winter. This behavior repeats annually and makes an affection to the structural capacity of member for both serviceability and ultimate level. In this paper, a cyclic temperature loading variation is calculated by analyzing the weather data of Korea for 20 years. In addition, an experimental work is planned to find the long term effect of temperature variation. Six RC slab are made with same dimension. Test parameters are loading duration (10, 20, 30 year) and whether it has pre-damage or not. Observation of stiffness variations according to cyclic loading period shows that the serious stiffness drop happens after 10 year's cyclic loading at summer while after 30 year's loading at winter. From the fracture test about slabs damaged by long term cyclic loading, however, the capacity of member such as initial stiffness and maximum strength were not changed except yield strength according to the period of long term cyclic loading. The yield strength tends to decrease after 20 year's cyclic loading.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.114-120
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• 2017

In this paper, the effect of the masonry infill walls on the seismic performance of the reinforced concrete(RC) frames with non-seismic details was evaluated through the static test of an masonry infilled RC frame sub-assemblage with non-seismic details of real size, and comparison with the test results of the RC frame sub-assemblage with non-seismic details. As the test results, lots of cracks occurred on the surface of the entire frame due to the compression of the masonry infilled wall, and the beam-column joint finally collapsed with the expansion of the shear crack and buckling(exposure) of the reinforcement. On the other hand, the stiffness of the shear force-story drift relationship decreased due to the wall sliding crack and column flexural cracks, and the strength finally decreased by around 60% of the maximum strength. The damage that concentrated on the upper and lower parts of columns was dispersed in the entire frame such as columns, a beam, and beam-column joints due to the wall, and the specimen was finally collapsed by expansion of the shear crack of the joint, not the shear crack of the column. Also, the stiffness of RC frame increased by 12.42 times and the yield strength by 3.63 times, while the story drift at maximum strength decreased by 0.18 times.

• The Korean Journal of Pain
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• v.21 no.2
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• pp.119-125
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• 2008

Background: Cerebral blood vessels are innervated by sympathetic nerves from the superior cervical ganglia (SCG), and these nerves may influence the cerebral blood flow. The purpose of the present study was to evaluate the neuroprotective effect of superior cervical sympathetic ganglion block in rats that were subjected to focal cerebral ischemia/reperfusion injury. Methods: Eighty male Sprague-Dawley rats (270-320 g) were randomly assigned to one of two groups (the ropivacaine group and a control group). In all the animals, brain injury was induced by middle cerebral artery (MCA) reperfusion that followed MCA occlusion for 2 hours. The animals of the ropivacaine group received $30{\mu}l$ of 0.75% ropivacaine, and their SCG. Neurologic score was assessed at 1, 3, 7 and 14 days after brain injury. Brain tissue samples were then collected. The infarct ratio was measured by 2.3.5-triphenyltetrazolium chloride staining. The terminal deoxynucleotidyl transferase mediated dUTP-biotin nick-end labeled (TUNEL) reactive cells and the cells showing caspase-3 activity were counted as markers of apoptosis at the caudoputamen and frontoparietal cortex. Results: The death rate, the neurologic score and the infarction ratio were significantly less in the ropivacaine group 24 hr after ischemia/reperfusion injury. The number of TUNEL positive cells in the ropivacaine group was significantly lower than those values of the control group in the frontoparietal cortex at 3 days after injury, but the caspase-3 activity was higher in the ropivacaine group than that in the control group at 1 day after injury. Conclusions: The study data indicated that a superior cervical sympathetic ganglion block may reduce the neuronal injury caused by focal cerebral ischemia/reperfusion, but it may not prevent the delayed damage.