• Korean Journal of Ichthyology
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• v.21 no.sup1
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• pp.29-37
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• 2009

The tiny fragment of freshwater body is providing home for huge biodiversity and resources for the existence of human. The competing demand for freshwater have been increased rapidly and it caused the declination of biodiversity in recent decades. Unlike the natural process of extinction in gradual progress, the current species extinction is accelerated by human activity. As a result many fish species are already extinct or alive only in captivity in the world and about fifty eight animal species are in endangered in Korea including eighteen freshwater species. Conservation of biodiversity is the process by which the prevention of loss or damage is attained, and is often associated with management of the natural environment. The practical action is classified into in-situ, or ex-situ depending on the location of the conservation effort. Recovery means the process by which the status of endangerment is improved to persist in the wild by re-introduction of species from ex-situ conservation population into nature or translocation of some population. However there are a lot of restrictions to complete it and successful results are known very rare in case. In this article the authors explore some strategies for conservation and restoration of freshwater fish species conducted in Korea for few years. The major causes are discussed in relation with the decline of freshwater fish diversity during few decades and some strategies are evaluated to advance the process of conservation. A study on the Korean bullhead, Pseudobagrus brevicorpus, is introduced as a case for ex-situ conservation and restoration in freshwater ecosystem.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.941-952
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• 2023

The metabolites of agrichemicals, such as organophosphorus pesticides, are known to be more hazardous than their parent pesticides. 3,5,6-trichloro-2-pyridinol (TCP) is a major degradation product of chlorpyrifos, one of the organophosphate insecticides widely used in agriculture. In vivo or in vitro exposure to chlorpyrifos has been known to interfere with male reproductive functions, leading to reduced fertility in mammals. Therefore, this study was performed to examine the changes in the fertilization competence of boar spermatozoa exposed to TCP. Sperm samples were subjected to varying concentrations of TCP (10, 50, 100, 200 µM) and different periods of incubation. Sperm motility, motion kinematics, viability, acrosome integrity, intracellular reactive oxygen species (ROS) production, and gene expression levels (ODf2, ZPBP2, AKAP3 and AKAP4) were evaluated after exposure of the sperm to TCP. A significant dose-dependent reduction in motility was observed in sperm samples incubated with TCP compared to the controls after both incubation periods. Sperm viability was significantly decreased in samples incubated with 50, 100, and 200 µM TCP in both incubation periods. A significantly lower percentage of normal acrosomes and gene expression levels were observed in sperm samples exposed to 50, 100, and 200 µM TCP after both incubation periods, compared to the controls. There was a significant increase in the ROS production in spermatozoa incubated with 100 - 200 µM TCP after both incubation periods. Consequently, the direct exposure of boar spermatozoa to TCP interferes with sperm functions and leads to decreased fertilization. In order to identify and address the various causes of reproductive decline, the impact of chemical metabolites needs to be discussed in depth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.1
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• pp.1-14
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• 2024

High soil salinity is the most severe threat to global rice production as it causes a significant decline in rice yield. Here, we investigated the effects of various plant extracts on rice plant stress associated with high salinity. Additionally, we examined various physiological and biochemical parameters such as growth, photosynthetic activity, chlorophyll content, and lipid peroxidation - in rice plants after treatment with selected plant extracts under salt stress conditions. Of the 11 extracts tested, four - soybean leaf, soybean stem, moringa (Moringa oleifera), and Undaria pinnatifida extracts - were found to effectively reduce salt stress. A reduction of only 3-23% in shoot fresh weight was observed in rice plants under salt stress that were treated with these extracts, compared to the 43% reduction observed in plants that were exposed to stress but not given plant extract treatments (control plants). The effectiveness varied with the concentration of the plant extracts. Water content was higher in rice plants treated with the extracts than in the control plants after 6 d of salt stress, but not after 4 d of salt stress. Although photosynthetic efficiency (Fv/Fm), electron transport rate (ETR), and the content of pigments (chlorophyll and carotenoid) varied based on the types and levels of stress and the extracts that the rice plants were treated with, generally, photosynthetic efficiency and pigment content were higher in the treated rice compared to control plants. Reactive oxygen species (ROS), such as superoxide radicals, hydrogen peroxide (H₂O₂), and malondialdehyde (MDA), increased as the duration of stress increased. ROS and MDA levels were lower in the treated rice than in the control plants. Proline and soluble sugar accumulation also increased with the duration of the stress period. However, proline and soluble sugar accumulation were lower in the treated rice than in the control plants. Generally, the values of all the parameters investigated in this study were similar, regardless of the plant extract used to treat the rice plants. Thus, the extracts found to be effective can be used to alleviate the adverse effects of stress on rice crops associated with high-salinity soils.

• Culinary science and hospitality research
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• v.23 no.1
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• pp.66-78
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• 2017

"Sarcopenia", sarcopenia is an old age syndrome, and used to describe the reduction of skeletal muscle. Initially, it was thought that sarcopenia was only a senile disease characterized by degeneration of muscle tissue. However, its cause is widely regarded as multifactorial, with neurological decline, hormonal changes, inflammatory pathway activation, declines in activity, chronic illness, fatty infiltration, and poor nutrition, all shown to be contributing factors. Skeletal muscle mass can be measured by a variety of methods, currently, the commonly used methods are dual-energy X-ray scanning (DXA), computer tomography (CT), magnetic resonance imaging (MRI), etc. Muscular skeletal disorders can also be assessed by measuring appendicular skeletal muscle (ASM), particularly muscle tissue content. At the same time, sarcopenia refers to skeletal muscle cell denervation, mitochondrial dysfunction, inflammation, hormone synthesis and secretion changes and a series of consequences caused by the above process and is a progressive loss of skeletal muscle syndrome, which can lead to the decrease of muscle strength, physical and functional disorders, and increase the risk of death. Sarcopenia is mainly associated with the aging process, but also related to other causes such as severe malnutrition, neurodegenerative diseases, and disuse and endocrine diseases associated with muscular dystrophy, and it is the comprehensive results of multi-factors, so it is difficult to define that sarcopenia is caused by a specific disease. With the aging problem of the population, the incidence of this disease is increasingly common, and seriously affects the quality of the life of the elderly. This paper reviews the etiology and pathogenesis of myopathy, screening methods and diagnosis, the influence of eating habits, etc, and hopes to provide reference for the diagnosis and treatment of this disease. At present, adequate nutrition and targeted exercise remain the gold standard for the therapy of sarcopenia.

• Journal of Digital Convergence
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• v.12 no.7
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• pp.11-20
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• 2014

This paper finds that the ultimate source of problems facing Korean mobile telecommunications such as excessive subsidies of handsets, waste of resources, and a vicious circle of expensive handsets and high prices for services, is bundling of handset and subscription. The analysis suggests that bundling causes consumers to confuse about prices of handsets and services, and firms focus on handset subsidy competition rather than on upgrading service qualities and lowering prices due to anti-competitive effects of bundling. Because most of the cost of bundling is passed on to consumers, the welfare of consumers decline. In particular, equality among consumers worsens due to price discriminations. To resolve these problems, unbundling of handset and subscription is a necessity. Mixed bundling allowing separate selling of handsets under bundling does not seem to work as a cure because bundling tends to be a dominant strategy. The best regulatory policy is a complete separation of handset and subscription.

• English & American cultural studies
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• v.18 no.2
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• pp.27-50
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• 2018

Old age is often compared as climbing mountains which requires walking out of breath, yet with wider vision. And it is also likened to the estuary where the river flows slowly and broadly into the open sea. Socially, old age has been regarded as a symbol of wisdom and reflection, and elderly people often take the role of sage who leads the community. On the other hand, the dementia, gray hair and wrinkles of old age were sometimes perceived as the decline of intellect and vitality. Especially, in the digital age in which technology makes people more sensitive to physical artificiality, the evaluation of the old age becomes more complex and obscure. In other words, some elderly people can not escape from Confucious convention of the elders first, which causes the denouncement by younger generations. On the other hand, some elderly people are becoming more adaptable to the trend of young people, emerging as the new elderly people. The anti-aging movement, early adaptation of IT, bioengineering regimen also strong for the advanced age. However, as the new elderly people are active in many fields of society, they also face intergenerational conflicts in some areas where remains the overlap between young people and them due to the limited openings in economy and culture. This study is a transdisciplinary research which can be called old age humanities. First of all, this paper looks at the aspects of lifestyles and intergeneration conflicts in old age in four Korean and Western literary works about the old people, and also searches how to improve the quality of the later life of old people, Overall, this paper aims to explore the way the old people can achieve the full life with the help of intergenerational dependency through building aging humanities and new communities for old people.

• Journal of The Geomorphological Association of Korea
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• v.18 no.2
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• pp.53-63
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• 2011

The changes and causes of channel section in Naeseongcheon River, a tributary of Nakdong River, during the long(1984~2001) and short(2009~2011) periods are analyzed. There are the declines of channel height with a maximum of approximately 2m in the most areas of the lower reaches during the past 20 years. These are thought as the influences of active aggregate collections and river dredging. The size of sand bar within the channel at the NM1 decreases greatly during the past 2 years. This may results from the decrease of sediment supply due to the Yeongju Dam construction in the upper reaches. However, the NM2 and NL2 where the natural channel are preserved experience the slight increase of height during the past 2 years. Therefore, the anthropogenic channel interferences in Naeseongcheon River have greatly influenced on the declines of channel height by the decrease of sediment supply.

• The Journal of the Korea Contents Association
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• v.15 no.8
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• pp.156-169
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• 2015

The negative awareness of a multiculturalism rises around the world because of various problems that happen with the multicultural phenomenon. Nevertheless, the reason we uphold multiculturalism is that multicultural phenomenon is an inevitable consequence of capitalism and the decline of multiculturalism might imply danger of bringing about radical nationalism. This study assumes that a distortion of multiculturalism is the result from a myth of romance film which affects the public perception as an integral component of a discourse. Grounded upon monomith, the narrative structure of romance film of which motive comes from courtly love makes people miscomprehend the value of multiculturalism because of the multicultural factor as substitute for romantic obstacle. As the character of romance movie is likely to be formed focusing on superficial images and denotations, this tendency causes the hierarchy and the representative minority drives out the rest of other minorities. The attempt to arouse people's tolerance and understanding of the other is frustrated both by the structure of binary oppositions and the clich$\acute{e}$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.3
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• pp.295-302
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• 2020

Disaster Preventing Zone (DPZ) is one of the zoning for land use regulation. Though the purpose of the designating of DPZs is to improve the area be safer, people has the negative recognition on DPZs. They think DPZs are regulation to restrict the actions and finally causes decrease on the land price. In this context, the aim of this study is to investigate the correlation between the designation of the DPZs and the land price of the DPZs in Seoul Metropolitan City. We applied the Difference in different (DID) which is one of the research methods to verify the cause and effect of specific policy. As a result, it was found statistically significant that land price of parcels designated as DPZs was 420,000 won higher than those not designated. The same results were obtained when the land characteristics were added, and the robustness of the model was indirectly confirmed. Based on the results, the designating of the DPZs was contrary to the expectation. Although it is necessary to analyze the result of the study more microscopically, It will be necessary to change the perception that it will decline.

• Journal of Biomedical Engineering Research
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• v.38 no.6
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• pp.308-312
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• 2017

Skeletal muscle function plays a very important role in quality of life. However, skeletal muscle causes functional decline under aging or some diseases. Exercise and muscle training are good solutions to delay sarcopenia, but there are limitations to those who are uncomfortable in exercise. For this reason, alternative interventions for muscle sarcopenia are required, and many studies proved the increase of skeletal muscle mass by electrical stimulation. In conventional studies, however, mouse skeletal muscle cells have been mostly used in experiments to identify electrical stimulation conditions while human derived cells have not been frequently utilized in these studies. Stimulation used for rehabilitation has been uniformly treated without the consideration of aging. In addition, many studies have been used with conventional petri dish usually requiring many numbers of cells, which is not appropriate for rare. Moreover, they are not usually condition uniformity of electrical field. In this study, we have developed an electrical stimulation device which consumes a small amount of cells and can form a uniform electrical field. With the system, we analyzed the skeletal muscle differentiation and Myotube thickness depending on the electrical stimulation condition.