• The Korean Journal of Ecology
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• v.26 no.3
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• pp.143-150
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• 2003

Korea has plentiful precipitation but rainfall events concentrate on several months of rainy season in her weather condition. Korea, therefore, experiences drought for a given period every year. Moreover the soil has usually low water holding capacity, as it is composed coarse particles originated from the granite. Response of several oaks and the Korean red pine (Pinus densiflora) on water stress showed that water budget was significant factor determining vegetation distribution. In addition, dehydration level due to cold resistance mechanism of several evergreen plants during the winter season was closely related to their distribution in natural condition. Experimental result under water stress showed that the Korean red pine was very tolerant to desiccation but the seedlings showed high mortality during the dry season. The mortality tended to proportionate to soil moisture content of each site. A comparison between soil moisture content during June when it is severe dry season and moisture content of the culture soil when the pine seedlings reached the permanent wilting point due to water withheld proved that high mortality during the dry season was due to water deficit. Water potential of sample plants measured during the exposure experiment to the air pollutant showed a probability that water related factors would dominate the occurrence of visible damage and the tolerance level of sample plants. In both field survey and laboratory experiment, plants exposed to air pollution showed more rapid transpiration than those grown in the unpolluted condition. The result would due to injury of leaf surface by air pollutants. Aluminum (Al/sup 3+/) increased in the acid soil not only inhibits root growth but also leads to abnormal distribution of root system and thereby caused water stress. The water stresses due to air pollution and soil acidification showed a possibility that they play dominating roles in inducing forest decline additionally to the existing water deficit due to weather and soil conditions in Korea. Sludge, which can contribute to improve field capacity, as it is almost composed of organic matter, showed an effect ameliorating the retarded growth of plant in the acidified soil. The effect was not less than that of dolomite known in widely as such a soil ameliorator. Litter extract contributed also to mitigate the water stress due to toxic Al/sup 3+/. We prepared a model showing the potential interaction of multiple stresses, which can cause forest decline in Korea by synthesizing those results. Furthermore, we suggested restoration plans, which can mitigate such forest decline in terms of soil amelioration and vegetation restoration.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.354-361
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• 2012

This study was conducted to evaluate on the freezing tolerance of introduced blueberry cultivars in Korea and to investigate availability of portable timber moisture meter for simple and rapid diagnosis of blueberry-shoot damage by freezing during wintering. Frost tolerance of blueberry cultivars showed big difference that rates of blueberry-shoot death were widely distributed from about 0% to 100% after wintering. Optical density in TTC reduction of blueberry twig treated low temperature was low in order of $-40^{\circ}C$ < $-21^{\circ}C$ < $4^{\circ}C$. Hardiness evaluation of visible injury in the cross-sectional surface color did not agree with that of rates of blueberry-shoot death during wintering. Lowest water content of blueberry stem measured by timber moisture tester during wintering was about 15%. During wintering, water contents of blueberry stems were higher at lower part of tree, but were low at end part of stems, and then when the blueberry grew again for spring, the water content gradually increased to 20~40%. Water content of blueberry stem with freezing injury during wintering decreased to under 5% by desiccation. Therefore it is assummed that the moisture content of blueberry stem injured by freezing during wintering was about under 14%, and it is expected that portable timber moisture meter could be available for rapid diagnosis of blueberry freezing injury in field.

• Korean Journal of Environment and Ecology
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• v.35 no.4
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• pp.408-423
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• 2021

We established and monitored survey sites in seven regions of Mt. Jiri to investigate population decline and change of the Korean fir (Abies koreana) over a ten-year period from 2009 to 2018. With the exception of one site (Seseok), the six remaining ones all showed a four-layer stratification structure. The importance value of Korean firs in all of the survey areas decreased significantly by 28.5%, from 55.7% in 2009 to 39.8% in 2018. The average population of objects with a diameter at breast height (DBH) of 5cm or more in all survey sites was 711 objects/ha in 2018, and the cumulative death rate from 2009 to 2018 was 10.8%. Among the death types, DS (dead standing) was the most dominant, comprising 82.4% of the total survey area. However, in Banyabong 1, which had a high gradient of 35°, the death types other than DS accounted for 44.2%. We estimate that A. koreana can maintain a stable population as its distribution type for each diameter class in the Saeseokpyeongjeon site showed a reverse-J shape. The average annual ring growth in all survey sites was 1.09 mm/year, with the most abundant growth observed in the Seseokpyeongjeon site, which was formed mainly by a subtree layer. The growth ring survey showed the estimated average age of A. koreana population in the Byeoksoryeong and Banyabong 1 sites to be 102 and 91 years, respectively, a general downward trend of vitality since 2013.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.3
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• pp.113-124
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• 2009

This study has attempted to calculate the intensity of illumination for the optimal growth environment of indoor plants after analyzing both damage to plant species and growth conditions as impacted by light conditions for the Kyobo Life Insurance greenhouse. The optical intensity of illumination has been estimated after investigating the problems of growth conditions based on an analysis of illumination by light condition, dead tree replacement cycle(weeks) and rate of damage of plant species. According to the investigation of illumination, the lowest difference was observed between the shaded spot in the south(531lux) and the sunny spot(602lux) while the largest difference(nearly 500lux) was detected between the shaded spot in the central area(210lux) and the sunny spot(782lux). According to an analysis of dead trees from 1990 to 2004, in terms of dead tree replacement cycle, Viburnum awabuki was the highest(161weeks), followed by Phyllostachys spp.(84weeks), Camellia japonica and Ternstroemia japonica(40weeks). Regardless of plant species, damage rate of plant were lower in the shaded spot and higher in the sunny spot. According to correlation and regression analyses with the intensity of illumination as an independent variable and the damage rate of plant species as a dependent variable, the damage rate of plant species increased as the intensity of illumination decreased. A dramatic decline in the rate of damage was observed at $500{\sim}600lux$. At 700lux, it reached the lowest level.

• Korean Journal of Environmental Biology
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• v.35 no.3
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• pp.413-425
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• 2017

This manuscript describes the relationship between climate change and forest growth, forest species, carbon stocks, and tree mortality. 1) In the aspect of forest growth, the growth of major coniferous species, including Pinus densiflora, had a negative correlation with temperature. On the other hand, major deciduous oak species, including Quercus variabilis and Quercus mongolica, had a positive correlation with temperature. 2) When considered in the aspect of the forest species distribution, various models commonly showed a decrease in the distribution of coniferous species and an increase in oak species due to climate change in the medium to long term. 3) From the carbon stock perspective, there was a difference in the estimation according to the status of forest management. Most of Korean forests will mature to become over-matured forest after year 2030 and are estimated to produce approximately 410 million ton forest biomass until 2090 with the current cutting regulations for sustainable forest management announced by the Korean Forest Service. 4) In the forest mortality, the mortality rate of the major coniferous species showed a clear tendency to increase higher temperatures while it decreased for the oak species with no verification of statistical significance. Moreover, the mortality of the subalpine coniferous species was projected to progress rapidly. considering the overall impacts described above, there should be a management strategy for coniferous species that are relatively vulnerable to climate change. Moreover, a sustainable forest plan in the aspect of ecosystem services, carbon sequestration and storage, which is linked to global issues such as Sustainable Development Goals, ecosystem services and negative emission.

• Tuberculosis and Respiratory Diseases
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• v.53 no.5
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• pp.485-496
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• 2002

Background : Nonsteroidal anti-inflammatory drugs (NSAIDs) are useful in the chemoprevention of colon cancers. Continuous NSAID use results in a 40% to 50% reduction in the relative risk of colorectal cancer. The precise mechanism by which NSAIDs prevent and/or cause the regression of colorectal tumors is not known. Some investigators have reported that certain NSAIDs induce apoptosis and alter the expression of the cell cycle regulatory genes in some carcinoma cells when administered at a relatively high concentration. However, the possibility of NSAIDs application as chemopreventive agents in lung cancers remains to be elucidated. To address this question, the human lung cancer cell line NCI-H1299 was used to investigate whether or not NSAIDs might induce the apoptotic death of NCI-H1299 cells. Methods : A viability test was carried out using a MTT assay. Apoptosis was measured by flow cytometric analysis and unclear staining(DAPI). The talytic activity of the caspase family was measured by the fluirigenic cleavage of biosubstrates. To define the mechanical basis of apoptosis, western blot was performed to analyze the expression of the death substrates(PARP and ICAD). Results : NaSaL significantly decreased the viability of the NCI-H1299 cells, which was revealed as apoptosis characterized by an increase in the $subG_0/G_1$ population and unclear fragmentation. The catalytic activity of caspase-3 protease began to increase after 24 Hr and reached a peak 30 Hr after treatment with 10 mM NaSaL. In contrast, caspase-6, 8, and 9 proteases did not have a significantly altered enzymatic activity. Consistent with activation of caspase-3 protease, NaSaL induced the cleavage of the protease biosubstrate. Conclusion : NaSaL induces the apoptotic death of NCI-H1299 human lung cancer cells via the activation of caspase-3 protease.

• Tuberculosis and Respiratory Diseases
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• v.59 no.1
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• pp.30-38
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• 2005

Background : Arsenic trioxide ($As_2O_3$) has been used to treat acute promyelocytic leukemia, and it induces apoptosis in a variety of solid tumor cell lines including non-small cell lung cancer cells. However, nonsteroidal antiinflammatory drugs (NSAID) can enhance tumor response to chemotherapeutic drugs or radiation. It was previously demonstrated that a combination treatment with $As_2O_3$ and sulindac induces the apoptosis of NCI-H157 human lung carcinoma cells by activating the caspase cascade. This study aimed to determine if a combination treatment augmented its apoptotic potential through other pathways except for the activation of the caspase cascade. Material and Methods : The NCI-H157 cells were treated with $As_2O_3$, sulindac and antioxidants such as glutathione (GSH) and N-acetylcysteine (NAC). The cell viability was measured by a MTT assay, and the level of intracellular hydrogen peroxide ($H_2O_2$) generation was monitored fluorimetrically using a scopoletin-horse radish peroxidase (HRP) assay. Western blotting and mitochondrial membrane potential transition analysis were performed in order to define the mechanical basis of apoptosis. Results : The viability of the cells was decreased by a combination treatment of $As_2O_3$ and sulindac, and the cells were protected using antioxidants in a dose-dependent manner. The increased $H_2O_2$ generation by the combination treatment was inhibited by antioxidants. The combination treatment induced changes in the mitochondrial transmembrane potential as well as the expression of the Bcl-2 family proteins, and increased cytochrome c release into the cytosol. However, the antioxidants inhibited the effects of the combination treatment. Conclusion : Combination treatment with $As_2O_3$ and sulindac induces apoptosis in NCI-H157 human lung carcinoma cells via ROS generation with a mitochondrial dysfunction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.398-404
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• 1993

This study was conducted in order to obtain the information for yield improvement in saline paddy. Saline concentration, growth and yield of rice, being subjected to different flooding times and days to transplanting were investigated in saline paddy with 0.35 % and 0.5 % salt concentration. Saline concentration of soil was increased to 0.41 % just after rotary in the paddy with 0.35 % salinity, but decreased to 0.20 % after 3 to 4 times of flooding treatment. And also that of surface water was decreased from 0.2 % to 0.11 %. Saline concentration of soil in 5cm depth was decreased to 0.31 % by one time flooding and to 0.22% by 3～4 times flooding but salinity below 7cm depth showed slight decrease. Seedling death was exceeded 37 % when transplanted one day after rotary in the paddy with 0.35% salinity. Death ratio was decreased to 20% by three times flooding and transplanting six days after rotary. In paddy with 0.5 % salinity, death ratio was high but the tendency was very similar to 0.35 % field. In 0.35 % saline paddy field, yields were increased by 14 % by three times flooding and transplanting six days after rotary as compared to one time flooding and transplanting are day after rotary. Therefore, 3 to 4 times flooding and transplanting 5 to 6 days after rotary are desirable in high saline paddy.

• Journal of Korean Society of Forest Science
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• v.112 no.3
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• pp.280-289
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• 2023

Diverse native tree species are distributed in Korean forests; however, information on their regeneration strategies is limited. This study analyzed seed rain from 2011 to 2013, seedling emergence, seedling survival, lifespan distribution, and the relationship between seedling mortality and herbaceous vegetation for 3 years, from 2012 to 2014, to understand the natural regeneration and early survival characteristics of Fraxinus rhynchophylla Hance in natural broad-leaved forests. Seed rain and emerged seedling density significantly differed among the years (p < .05). An increase in seed rain was followed by an increase in seedling emergence in the following year. Seed rain in 2013 and seedling emergence in 2014 showed a significant correlation (p < .05), confirming the trait of F. rhynchophylla seeds that germinate in the following year after seed production. Seedlings emerged in late spring and early summer. Of the seedlings, 78% emerged in the early summer of 2014. Most seedlings died immediately after emergence. Of the seedlings that emerged in August 2012, 56% died within 2 months, and 38% of those that emerged in July 2014 died within 1 month. Shade and competition against ground vegetation chiefly affected the seedling survival of F. rhynchophylla. Fraxinus rhynchophylla showed mast seeding, with a large number of seed production in a particular year. A surge of seedling emergence followed in the early summer of the next year. However, most seedlings died in the same year of emergence. Fraxinus rhynchophylla has a high seedling mortality, but mast seeding and the resulting high seedling emergence produce a few survived seedlings, enabling the continuation of the F. rhynchophylla population. Efforts and research on the natural regeneration of native tree species are required to effectively manage natural forests in Korea.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.95-101
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• 2008

Purpose: Hydrogen peroxide which is one of the reactive oxygen species has been seen to cause various diseases, various cellular disinfections, gene transformation and cell death. The goals of this study were to determine the protective effect of EGCG against $H_2O_2$-induced apoptotic death in conjunctival cell lines. Methods: We measured cell viability by MTT assay and analyzed DNA fragmentation to check up a distinctive feature in cell death and measured the removal ability of free radicals by DPPH free radical scavenging assay and evaluated the oxygen free radical's quantity in the cell by DCFH-DA assay. The mRNA expression in the cell were examined by RT-PCR. Results: Cell viability and free radical scavening activites was significantly increased in dose dependently after cell was exposed to EGCG. And DNA fragmentation and intracellular ROS was decreased. It was showed the mRNA expression which increase of bcl-2, bcl-xL expression and decrease of bax expression. Conclusions: From these results, it suggests that EGCG has an antioxidant effect and protects conjunctival cell lines from the $H_2O_2$-mediated apoptosis through the modulation of the mRNA expression.