• Molecules and Cells
• /
• v.43 no.3
• /
• pp.264-275
• /
• 2020

Reactive oxygen species (ROS) play a significant role in intracellular signaling and regulation, particularly when they are maintained at physiologic levels. However, excess ROS can cause cell damage and induce cell death. We recently reported that eIF2α phosphorylation protects hepatocytes from oxidative stress and liver fibrosis induced by fructose metabolism. Here, we found that hepatocyte-specific eIF2α phosphorylation-deficient mice have significantly reduced expression of the epidermal growth factor receptor (EGFR) and altered EGFR-mediated signaling pathways. EGFR-mediated signaling pathways are important for cell proliferation, differentiation, and survival in many tissues and cell types. Therefore, we studied whether the reduced amount of EGFR is responsible for the eIF2α phosphorylation-deficient hepatocytes' vulnerability to oxidative stress. ROS such as hydrogen peroxide and superoxides induce both EGFR tyrosine phosphorylation and eIF2α phosphorylation. eIF2α phosphorylation-deficient primary hepatocytes, or EGFR knockdown cells, have decreased ROS scavenging ability compared to normal cells. Therefore, these cells are particularly susceptible to oxidative stress. However, overexpression of EGFR in these eIF2α phosphorylation-deficient primary hepatocytes increased ROS scavenging ability and alleviated ROS-mediated cell death. Therefore, we hypothesize that the reduced EGFR level in eIF2α phosphorylation-deficient hepatocytes is one of critical factors responsible for their susceptibility to oxidative stress.

• Journal of the HCI Society of Korea
• /
• v.13 no.3
• /
• pp.65-73
• /
• 2018

Game balance settings are crucial to game design. Game balancing must take into account a large amount of numerical values, configuration data, and the relationship between elements. Once released and served, a game - even for a balanced game - often requires calibration according to the game player's preference. To achieve sustainability, game balance needs adjustment while allowing for small changes. In fact, from the producers' standpoint, game balance issue is a critical success factor in game production. Therefore, they often invest much time and capital in game design. However, if such a costly game cannot provide players with an appropriate level of difficulty, the game is more likely to fail. On the contrary, if the game successfully identifies the game players' propensity and performs self-balancing to provide appropriate difficulty levels, this will significantly reduce the likelihood of game failure, while at the same time increasing the lifecycle of the game. Accordingly, if a novel technology for game balancing is developed using artificial intelligence (AI) that offers personalized, intelligent, and customized service to individual game players, it would bring significant changes to the game production system.

• Journal of Environmental Science International
• /
• v.19 no.5
• /
• pp.655-663
• /
• 2010

Today, the importance of environmental education is a matter we are all concerned about. The environment surrounding us, such as the air we breathe, the water we drink, and the soil plants grow in, is critical for our survival. Currently there is a lot of interest in environmental education at the elementary, middle, and high school levels. This is a result of the deep recognition of the importance of the environment. However the environmental education being conducted in schools is not yet at a satisfactory level. The practical issues, including an entrance exam-oriented atmosphere, student' and parents' lack of understanding, and teachers' lack of expertise in environmental education, interfere with the stability of environmental curriculum in the schools. Accordingly, we need to devise an alternative environmental curriculum due to the fact that it hasn't been included as a regular subject in the curriculum of many national schools. This study, carried out from April to December 2009, was an examination of the effect of volunteer work at the place of ecology experience on the environmental sensitivity & state-trait anxiety of the 61 Gifted Students. The students were divided into two groups. The test group consisted of 30 gifted students who did volunteer work at the place of ecology experience run by Ulsan Science High School, in Ulsan Metropolitan City. The control group consisted of the rest of the students. The following are the study results: First, the volunteer work at the place of ecology experience was influential in increasing the environmental sensitivity of the gifted students. Second, the volunteer work at the place of ecology experience was influential in decreasing the state anxiety of in gifted students. Third, the volunteer work at the place of ecology experience was influential in decreasing the trait anxiety of in gifted students. Fourth, the volunteer work at the place of ecology experience positively influenced not only the gifted students' view of environmental education, but also their overall character.

• Journal of the Economic Geographical Society of Korea
• /
• v.12 no.4
• /
• pp.540-556
• /
• 2009

The hub and spoke network is a critical network-based infrastructure that is widely applied in current transportation and telecommunications systems, including Internets, air transportation networks and highway systems. This main idea of hub location models is to construct a network system which achieves the economy of scale of flows. The main purpose of this study is to introduce new hub location problems that take into account network reliability. Two standard models based on assignment schemes are proposed, and a minimum threshold model is provided as an extension in terms of hub network design. The reliability and interaction potentials of 15 nodes in the U.S. are used to examine model behaviors. According to the type of models and reliability, hubs, and minimum threshold levels, relationships among the flow economy of scale, network costs, and network resiliency are analyzed.

• The KIPS Transactions:PartD
• /
• v.14D no.7
• /
• pp.791-800
• /
• 2007

The purpose of the research is to investigate the impact of the implementation and recognition for KM strategies on KM performances in public enterprises. The research identified critical factors of KM strategies and performances through literature review, measured the degrees of implementation and significance recognition for the strategies targeting public enterprises, and analyzed the KM performance levels based on the combined degrees of the implementation and the recognition for KM strategies. The findings illustrate that not only the KM strategies implementation, but also the significance recognition can affect the KM performances. The researchers urge that organizations, in advance, should request their employees' understanding and significance recognition for KM strategies to successfully implement their knowledge management.

• Genomics & Informatics
• /
• v.7 no.4
• /
• pp.203-207
• /
• 2009

The target of rapamycin (TOR) signaling pathway conserved from yeast to human plays critical roles in regulation of eukaryotic cell growth. It has been shown that TOR pathway is involved in several cellular processes, including ribosome biogenesis, nutrient response, autophagy and aging. However, due to the functional diversity of TOR pathway, we do not know yet some key effectors of the pathway. To find unknown effectors of TOR signaling pathway, we took advantage of a green fluorescent protein (GFP)-tagged collection of budding yeast Saccharomyces cerevisiae. We analyzed protein abundance changes by measuring the GFP fluorescence intensity of 4156 GFP-tagged yeast strains under inhibition of TOR pathway. Our proteomic analysis argues that 83 proteins are decreased whereas 32 proteins are increased by treatment of rapamycin, a specific inhibitor of TOR complex 1 (TORC1). We found that, among the 115 proteins that show significant changes in protein abundance under rapamycin treatment, 37 proteins also show expression changes in the mRNA levels by more than 2-fold under the same condition. We suggest that the 115 proteins indentified in this study may be directly or indirectly involved in TOR signaling and can serve as candidates for further investigation of the effectors of TOR pathway.

• The Korean Journal of Quaternary Research
• /
• v.14 no.2
• /
• pp.101-107
• /
• 2000

Using the phytogram system, this study monitored hourly environmental factors(climate and soil), and radial growths and cambium activities of conifers in Worak mountain for 28 months from May 1996 to October 1998 to examine the influences of climatic factors on tree growths/carnbium activities of conifers in Worak Mountain, Korea. The phytogram system first puts a fine electrode into cambial zone. This device can automatically record environmental factors and cambium electrochemistry(hydration and proton levels). Dendrometers are attached to the phytogram for monitoring seasonal dynamics of cambial growth. We compared the results of radial growth by species and by diameter class. The growth decreased in order of Larix leptolepis, Pinus densiflora and Pinus rigida. Pre-monsoon growths were fast and May-June moisture regime was the most critical for all species. In the middle of September, radial growths were finished. The proton level and stem diameter reached the minimum at 4 p.m. On the other hand, the hydration level reached the maximum at 4 p.m. This diurnal change resulted from transpiration and the release of water from phloem storage to sapwood through xylem stream.

• Journal of the Korean association of regional geographers
• /
• v.7 no.2
• /
• pp.1-16
• /
• 2001

This paper is to examine the trends and structures of unemployment as well as its spatial patterns in Germany. Germany once achieved a well-developed employment system and full employment. Since 1970, however, unemployment has been one of the major issues in Germany. During the last three decades the unemployment rate has risen to unprecedented levels and stayed high. After the German unification, especially, labor market is characterized by the mass unemployment and the structural selective process of unemployment to be imposed on German workers. And regarding to the spatial patterns of massive unemployment, this study shows critical disparities between South and North Germany being overlapped with new disparities between East and West Germany. We can explain the regional differentiation of unemployment on the base of typical mismatch of labour market allocation. It is also shown that massive unemployment is related not only to policy shifts in labor market but also to structural transformation after the unification.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.23 no.1
• /
• pp.77-87
• /
• 2020

National parks and other protected areas often do not adequately protect national biodiversity because they were originally created for socio-economic and/or aesthetic values. The Korean government has committed to expanding the extent of protected areas to fulfill its commitments to the Aichi Biodiversity Convention. To do so, it is necessary to quantify the current levels of biodiversity representation within existing protected areas and to identify additional conservation needs for vulnerable species and ecological systems. In this study, we assess the proportion of species ranges found in South Korea's protected areas, for the species documented in the 3^rd National Ecosystem Survey. We modeled the range distribution of 3,645 species in the following taxonomic groups; plants (1,545 species), mammals (35), birds (132), herptiles (35), and insects (1,898) using the MaxEnt species distribution model and calculated how much of each species' range is within protected areas. On average, 17.4% of plant species' ranges are represented in protected areas, while for mammals and insects an average 12.0% is currently conserved. Conservation representation for herptiles averages 9.3%, while it is 8.6% for birds. Although large proportions of species that have restricted distributions should be represented in protected areas, 17 plant species, two insects (Parnassius bremeri and Lasioglossum occidens), and one bird species (Phylloscopus inornatus) with ranges smaller than 1,000 ㎢ have less than 10% of their ranges within protected areas. Establishing specific conservation goals such as the protection of endangered species or vulnerable taxonomic groups will increase the efficiency of the biodiversity conservation strategies. In addition, lowland coastal areas are critical for biodiversity conservation because the protected areas in South Korea are mainly composed of high mountainous areas.

• Journal of the Korean Society for information Management
• /
• v.28 no.1
• /
• pp.23-42
• /
• 2011

This study is to compare the descriptive cataloging rules between AACR2 and RDA, and then to find a direction of future cataloging and KCR 4. RDA is new cataloging rules that embody the International Cataloging Principles(2009), FRBR and FRAD. It is a structure of bibliographic control of all kinds of resources, and the rules can be flexibly applicable in the international cataloging community. It is critical to embody RDA in KCR 4 because RDA is likely to affect the future cataloging through its collocation function and relation function to construct semantic web of OPAC. This study analyzed the descriptive rules of work, expression, and manifestation based on RDA draft(2008) of JSC for Development of RDA. It analyzed the changes in the cataloging rules from AACR2 to RDA in such descriptive areas as title, type of resources, statement of responsibility, edition, publication, physical description and series in the manifestation level, and the preferred access points in both expression and work levels. The findings of this study will provide implications in revising KCR4.