• Environmental and Resource Economics Review
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• v.12 no.3
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• pp.397-425
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• 2003

This paper develops a simple theoretical model that is consistent with the empirical evidence of an inverted U-shpated relationship between pollution and per capita income, which is so-called environmental Kuznets curve in this literature. Also, by incorporating the issue of environmental externality into an endogenous growth model, I investigate the circumstances under which growth can be sustained with the optimal control of pollution, and hence the sustainable development can be achieved. In order to study the problem of implementing the social optimum in a market economy, I examine the optimality of three different kinds of environmental policy instruments; pollution tax, pollution-permit trading system (pollution voucher), and direct regulation. This paper shows that the optimum can be implemented with a pollution tax or with a voucher system. Also, it is shown that the socially optimal rate of pollution tax should increase proportionally to the growth rate of consumption.

• International Area Studies Review
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• v.13 no.3
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• pp.269-286
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• 2009

The aim of the paper is to study environmental impacts of openness and trade in korea, and analyze the relationships between trade, development and environment. This study established endogenous determinants such as inflow FDI, level of environmental pollution and economic growth, and assumed a proposition that each individual variables are in two-way relationships among the three key variables such as the openness, the environment and GDP. To estimate a system of equations, a simultaneous equation model is used because the simultaneity problems are formidable. The results show that the more openness and economic growth increase, the more level of environmental quality improve. This study also found that FDI and openness, and economic growth bring along the level of environmental quality.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.233-238
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• 2020

Process-based model (PBM), based on the interactions between endogenous physiological processes and many environmental factors, can be a powerful tool for estimating crop growth and productivity. Carbon acquisition and biomass accumulation are the main components in PBM, so it has become important to understand and integrate gas exchange process in crop model. This study aimed to assess the applicability of FvCB model (a leaf model of C3 photosynthesis proposed by Farquhar, von C aemmerer, and Berry (1980)) in onion (Allium cepa L.). For parameterization, two early-maturing onion cultivars, 'Singsingball' and 'Thunderball', grown in a temperature gradient plastic film house, were used in measuring leaf net CO2 assimilation rate (A), and then, parameter estimation was carried out for four parameters including Vcmax (maximum rate of carboxylation), Jmax (maximum rate of electron transport), TPU (rate of triose phosphate utilization), and Rd (Dark respiration rate). The gas-exchange model calibrated in this research is expected to be able to explain the photosynthetic responses of onion under various environmental conditions (R2=0.95***).

• Molecules and Cells
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• v.38 no.7
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• pp.643-650
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• 2015

The use of conditioned medium from mesenchymal stem cells may be a feasible approach for regeneration of bone defects through secretion of various components of mesenchymal stem cells such as cytokines, chemokines, and growth factors. Mesenchymal stem cells secrete and accumulate multiple factors in conditioned medium under specific physiological conditions. In this study, we investigated whether the conditioned medium collected under hypoxic condition could effectively influence bone regeneration through enhanced migration and adhesion of endogenous mesenchymal stem cells. Cell migration and adhesion abilities were increased through overexpression of intercellular adhesion molecule-1 in hypoxic conditioned medium treated group. Intercellular adhesion molecule-1 was upregulated by microRNA-221 in mesenchymal stem cells because microRNAs are key regulators of various biological functions via gene expression. To investigate the effects in vivo, evaluation of bone regeneration by computed tomography and histological assays revealed that osteogenesis was enhanced in the hypoxic conditioned medium group relative to the other groups. These results suggest that behavioral changes of endogenous mesenchymal stem cells through microRNA-221 targeted-intercellular adhesion molecule-1 expression under hypoxic conditions may be a potential treatment for patients with bone defects.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.1
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• pp.97-110
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• 2010

The wound healing process can be categorized as follows : inflammation, fibroplasia, neovascularization, collagen deposition, epithelialization, and wound contraction. During the healing process, various growth factors are secreted to accelerate wound healing. Previous studies have demonstrated that endogenous growth factors, such as vascular endothelial growth factor(VEGF) are the important regulatory polypeptides for coordinating the healing process. They are released from macrophages, fibroblasts, and keratinocytes at the site of injury and participate in the regulation of reepithelization, granulation tissue formation, collagen synthesis and neovascularization. Onchung-Um has been used clinically to treat various skin diseases. In addition, Onchung-Um has been also used for congestive inflammations. In the present study, we evaluated the effects of Onchung-Um on wound healing process and wound size reduction in rats. Full-thickness skin wounds ($15mm\;{\times}\;15mm$) were created on the back of rats. Rats were then divided into 2 groups : The Onchung-Um treated group that was orally administered with a dose of 193.9mg/100g of Onchung-Um extract per day for 15 days and Control group without Onchung-Um administration. Moreover, the histological changes and VEGF immunoexpressions of two groups were estimated. In results, wound closures were significantly accelerated by oral administration of Onchung-Um extract. Furthermore, in Onchung-Um treated group, there were significant increases in fibroblast migration, epithelialization compared with the Control group. VEGF expressions were also increased in Onchung-Um treated group. This study has therefore demonstrated the Onchung-Um can significantly improve the quality of wound healing and scar formation and the oral administration of Onchung-Um extract may increase early tissue angiogenesis in the incisional wound of an experimental animal model.

• Journal of the Economic Geographical Society of Korea
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• v.14 no.4
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• pp.453-466
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• 2011

The main aim of this paper is to explore the Korean development strategy in the context of trajectories of the economic development from 1961 to 2010. The fast and high growth in the period of 1961 and 2010 resulted from the 'export-oriented industrialization' through a combination of 'mass production-mass exports' and '(relatively) high productivity-low wages' up to the late 1980s, a mixture of 'mass production-mass exports' and '(relatively) high productivity-high wages' to the late 1990s, and a combination of the reformation of public and private sectors for overcoming the Korean financial crisis and the gradual improvement of the marketization and social safety net since 2000. With respect to this model of development, the global and national modes of regulation were established. Along with the formation of endogenous forces (as the national mode of regulation), that of exogenous forces (as the global mode of regulation) are the important rules of the game at the global level, which lead and stabilize the process of accumulation by the export-led industrialization in Korea. In this respect, the establishment of global modes of regulation is led by exogenous forces such as trade regulations, exchange rates, global-Korean industrial relations, and global regulations of loans to developing countries. On the other hand, the national modes of regulation are formed by endogenous forces such as the triangular relationship of the state, capital and labor.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.317-325
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• 2015

Peach (Prunus persica L.) is a model species for stone fruit studies within the Rosaceae family. Auxin plays an important role in the development of peach fruit. To reveal the distribution of auxin in the tissues of peach fruit, immunohistochemical localization of IAA was carried out in the seed, mesocarp, and endocarp in developing peach fruit using an anti-indole-3-acetic acid (anti-IAA) monoclonal antibody. A strong IAA signal was observed throughout the outer and inner integument during peach fruit development, and the distribution was zonal. The IAA signal was mainly focused in mucilage layers in the outer integument. The outer integument may function to produce or store IAA in the seed; a strong IAA signal was detected in the cells around the vascular tissue, whereas a weak IAA signal was located in the vascular tissues. In the mesocarp, the cells around the vascular bundle tissue gave rise to an IAA signal that increased in the late phase of fruit growth, which coincided with a significant increase in fruit growth. The distribution of IAA, however, was changed when fruit was treated with auxin transport inhibitors NPA (1-N-naphthylphthalamic acid) or TIBA (2, 3, 5-triiodobenzoic acid); in mesocarp tissues, an IAA signal was detected mainly in vessels of the treated fruit. During the critical period of endocarp lignification, the vessel lignification process was negatively correlated with IAA signal. The present results confirmed that the distribution of IAA was different in various tissues of peach fruit according to the developmental stage. This research provides cytological data for further study of the regulatory mechanism of auxin in peach fruit.

• Journal of Nutrition and Health
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• v.31 no.3
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• pp.279-288
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• 1998

This study explored the effect of calcium levels and/or ovariectomy on bone metabolism using female Sprague-Dawley weanling rats as a model . Rats received a low (0.1%) calcium diet for 8 weeks. The rats were then divided into three subgroups that were fed 0.1% ,0.5% and 1.5% calcium diets for 8 weeks after operation. The results of this experiment indicate that body weight gin was higher in ovariectomy groups than in sham groups regardless of calcium level and food intake. Serum Ca and P concentrations were of normal level regardless of calcium level and ovariectomy. Estrogen concentration was low in the ovariectomized group. Serum alkaline phophatase activity and urinary hydroxyproline have been used as markers of bone formation and resorption. These values were increased in ovariectomized groups. The weight, length and breaking force of femur were not significantly different between the groups. Ash, Ca, P and total lipid contents in femur and lumbar were decreased in the groups fed low calcium . Mg content was decreased in the ovariectomy and total protein content was not affected by calcium level and ovariectomy. The effect groups of ovarectomy on calcium contents of bone was more prominent in lumbar than in femur. In conclusion, though low calcium intakes during growth period may retard the attainment of peak bone mass, calcium supplementation after this period increased bone growth and mineral contents, but not significant effect in three calcium levels. Furthermore, calcium intake was shown to have a greater influence on the mineral contents of femur than of lumbar, and removal of endogenous estrogen production by ovariectomy was shown to be more deleterious on the ash and calcium contents of the lumbar than of femur.

• Environmental and Resource Economics Review
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• v.21 no.2
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• pp.371-416
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• 2012

This study has developed Computable General Equilibrium (CGE) model reflecting endogenous growth economic theory, with the aim of analyzing double dividend hypothesis. This study analyzes possibility of economic growth and environmental improvement at the same time when government recycles the revenue of carbon tax to reduce existed taxes such as consumption tax, labor income tax, corporate tax. It also assesses the case of subsidy on R&D investment of renewable energy. With new and renewable generation technology adopted and disseminated, GDP loss would be lessened to a great degree. Tax recycling would provide economic gain by reducing distortion existed in the existing fiscal structure. The magnitude of economic gains from carbon tax recycling is biggest for recycling into corporate tax, and labor income tax, and then consumption tax in this order. It is also shown that double dividend effects occur in dynamic terms when government uses a carbon tax revenue to subsidize on R&D investment. At the end of the analysis period, emissions reduction would not result in GDP loss but in GDP gain. In particular, recycling into R&D increase would produce the largest and fastest GDP gain. Thus, implementing emissions reduction target would require careful consideration of economic effects by various policy instrument, including carbon tax.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.39
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• pp.8.1-8.8
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• 2017

Background: For an effective bone graft for reconstruction of the maxillofacial region, an adequate vascular network will be required to supply blood, osteoprogenitor cells, and growth factors. We previously reported that the secretomes of bone marrow-derived mesenchymal stem cells (MSC-CM) contain numerous growth factors such as insulin-like growth factor (IGF)-1, transforming growth factor $(TGF)-{\beta}1$, and vascular endothelial growth factor (VEGF), which can affect the cellular characteristics and behavior of regenerating bone cells. We hypothesized that angiogenesis is an important step for bone regeneration, and VEGF is one of the crucial factors in MSC-CM that would enhance its osteogenic potential. In the present study, we focused on VEGF in MSC-CM and evaluated the angiogenic and osteogenic potentials of MSC-CM for bone regeneration. Methods: Cytokines in MSC-CM were measured by enzyme-linked immunosorbent assay (ELISA). Human umbilical vein endothelial cells (HUVECs) were cultured with MSC-CM or MSC-CM with anti-VEGF antibody (MSC-CM + anti-VEGF) for neutralization, and tube formation was evaluated. For the evaluation of bone and blood vessel formation with micro-computed tomography (micro-CT) and for the histological and immunohistochemical analyses, a rat calvarial bone defect model was used. Results: The concentrations of IGF-1, VEGF, and $TGF-{\beta}1$ in MSC-CM were $1515.6{\pm}211.8pg/mL$, $465.8{\pm}108.8pg/mL$, and $339.8{\pm}14.4pg/mL$, respectively. Tube formation of HUVECs, bone formation, and blood vessel formation were increased in the MSC-CM group but decreased in the MSC-CM + anti-VEGF group. Histological findings suggested that new bone formation in the entire defect was observed in the MSC-CM group although it was decreased in the MSC-CM + anti-VEGF group. Immunohistochemistry indicated that angiogenesis and migration of endogenous stem cells were much more abundant in the MSC-CM group than in the MSC-CM + anti-VEGF group. Conclusions: VEGF is considered a crucial factor in MSC-CM, and MSC-CM is proposed to be an adequate therapeutic agent for bone regeneration with angiogenesis.