• Journal of Soil and Groundwater Environment
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• v.23 no.3
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• pp.1-9
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• 2018

This study is aimed to quantitatively evaluate the effects of drought on groundwater system in rural areas. For this purpose, the standardized groundwater level index (SGI) was used for 68 groundwater monitoring wells. To determine accumulation period (AP) which represents the month with the highest correlation coefficient between SGI and SPI, correlation analysis between the two for 68 wells were peformed. The results indicated the AP values ranged in 1~3 months for most of the well, but it was 7~10 months in some wells. These results can be interpreted such that the total amount of groundwater will not decrease significantly in long-term drought situations unlikely the reservoirs with the high AP values. The nationwide maximum AP values were 4.1 and 4.0 in Chungbuk-do and Gyeongnam-do, while the minimum AP values were 1.8 and 2.0 in Gangwon-do and Chungnam-do, respectively. The maximum and minimum values of correlation coefficient were 0.623 and 0.459 in Gyeongnam-do and Chungnam-do/Chungbuk-do, respectively. Consequently, it could be concluded that the wells with low AP value tend to respond to short-term drought, but it has little effect on groundwater system when the long drought occurs.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.122-134
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• 2010

We investigated the levels of resistance and accumulation of terapyrroles, reactive oxygen species, lipid peroxidation, and antioxidative enzymes for reasons of growth reduction in herbicide-transgenic rice overexpressing Myxococcus xanthus, Arabidopsis thaliana, and human protoporphyrinogen oxidase (Protox) genes. The transgenic rice overexpressing M. xanthus (MX, MX1, PX), A. thaliana (AP31, AP36, AP37), and human (H45, H48, H49) Protox genes showed 43~65, 41~72 and 17~70-fold more resistance to oxyfluorfen, respectively, than the wild type. Among transgenic rice lines overexpressing Protox genes, several lines showed normal growth compared with the wild type, but several lines showed in reduction of plant height and shoot fresh weight under different light conditions. However, reduction of plant height of AP37 was much higher than other lines for the experimental period. On the other hand, the reduction of plant height and shoot fresh weight in the transgenic rice was higher in high light condition than in low light condition. Enhanced levels of Proto IX were observed in transgenic lines AP31, AP37, and H48 at 7 days after seeding (DAS) and transgenic lines PX, AP37, and H48 at 14 DAS relative to wild type. There were no differences in Mg-Proto IX of transgenic lines except for H41 and H48 and Mg-Proto IX monomethyl ester of transgenic lines except for MX, MX1, and PX. Although accumulation of tetrapyrrole intermediates was observed in transgenic lines, their tetrapyrrole accumulation levels were not enough to inhibit growth of transgenic rice. There were no differences in reactive oxygen species, MDA, ALA synthesizing capacity, and chlorophyll between transgenic lines and wild type indicating that accumulated tetrapyrrole intermediate were apparently not high enough to inhibit growth of transgenic rice. Therefore, the growth reduction in certain transgenic lines may not be caused by a single factor such as Proto IX, but by interaction of many other factors.

• Analytical Science and Technology
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• v.8 no.2
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• pp.171-179
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• 1995

This is an analytical study of germanium by adsorption stripping squarewave voltammetry. Tannic acid was used as a ligand. The accumulation potential was -0.2V, accumulation time was carried out for 60 second under constant stirring, followed by a 20 second quiescent period, and frequency was 10Hz. A hanging mercury drop electrode was used as a working electrode and acetate buffer solution, pH=4.5, as supporting electrolyte. The proper conditions of ligand for germanium analysis was established. The effect of metal ions(lead, cupper, silicon, tin, gallium) on germanium peak was also studied.

• Journal of The Geomorphological Association of Korea
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• v.17 no.2
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• pp.41-52
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• 2010

The paleovegetation environments relevant to the geomorphic properties were constructed by pollen analysis in the coastal dune (S1) and marginal trench (S4) of Ssangho at the Osan-ri site. The organic sand layer in the coastal dune (S1) accumulated on the remains of the Neolithic Age correlates to approximately 4,000 yr BP and the pollen zone can be divided with a boundary of approximately 2,000 yr BP. Pinus thunbergii definitely dominated and a small quantity of Quercus. Pollenzone I can be characterized by the dominance of AP and Compositae. The pollenzone II as the dominant period of NAP like Gramineae, Artemisia and Fagopyrum shows the properties of agricultural period. During the times of accumulation of upper organic layer in alluvial plain (S4), broad-leaved trees such as Alnus were dominant and Compositae, Gramineae, Artemisia, Typha, Umbelliferae and Persicaria show the high occurrence rates. The pollen composition of S4 indicates the agricultural activities with the dominance of NAP and correlates to the pollenzone II of the coastal dune (S1).

• Journal of Soil and Groundwater Environment
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• v.27 no.5
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• pp.1-9
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• 2022

A correlation analysis was performed to investigate differences in the response of surface water and groundwater to drought using the Standardized Precipitation Index (SPI). Water level data of 20 agricultural reservoirs, 4 dams, 2 rivers, and 8 groundwater observation wells were used for the analysis. SPI was calculated using precipitation data measured at a nearby meteorological station. The water storage of reservoirs and dams decreased significantly as they responded sensitively to the drought from 2014 to 2016, showing high correlation with SPI of the relatively long accumulation period (AP). The responses of rivers varied greatly depending on the presence of an upstream dam. The water level in rivers connected to an upstream dam was predominantly influenced by the dam discharge, resulting in very weak correlation with SPI. On the contrary, the rivers without dam exhibited a sharp water level rise in response to precipitation, showing higher correlation with SPI of a short-term AP. Unlike dams and reservoirs, the responses of groundwater levels to precipitation were very short-lived, and they did not show high correlation with SPI during the long-term drought. In drought years, the rise of groundwater level in the rainy season was small, and the lowered water level in the dry season did not proceed any further and was maintained at almost the same as that of other normal years. Conclusively, it is confirmed that groundwater is likely to persist longer than surface water even in the long-term drought years.

• Journal of Life Science
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• v.24 no.10
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• pp.1085-1091
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• 2014

The purpose of this study was to determine the effect of selenate on adipocyte differentiation and to identify genes involved in the modulation of adipogenesis in 3T3-L1 cells. To test the effect of selenate on adipocyte differentiation, adipogenesis was induced in cells using various concentrations ($0-100{\mu}M$) of selenate. Various phases of adipogenesis were induced: postconfluent (PC), early phase (EP, d0-d2), postmitotic growth arrest (PM, d2-d4), and all period (AP). The PC cells exposed to selenate for 24 h displayed dose-dependent inhibition of intracellular lipid droplet accumulation on day 6 of adipogenesis. Two days of selenate treatment at EP or AP inhibited adipogenesis, with an approximately 20-80% reduction in lipid accumulation compared to that of a control (p<0.05). When preadipocytes were exposed to selenate during the PM period, the antiadipogenic effect of selenate was attenuated. Two types of selenoprotein genes (Seps1 and Sepp1) were up-regulated by the selenate treatment during mitotic clonal expansion, whereas these genes were down-regulated during PM growth arrest (p<0.05). The findings demonstrate the antiadipogenic function of selenate and the possible involvement of Sepp1 and Seps1 genes in selenate-inhibited adipogenesis in 3T3-L1 cells.

• Microbiology and Biotechnology Letters
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• v.45 no.1
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• pp.27-34
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• 2017

$C/EBP{\beta}$ and $C/EBP{\delta}$ are required for the initiation of adipogenesis and induce the expression of key adipogenic regulators, such as $PPAR{\gamma}$ and $C/EBP{\alpha}$. In the present study, we have examined the effects of silibinin and its possible molecular mechanisms in regulating adipocyte differentiation and expression of $C/EBP{\beta}$ and $C/EBP{\delta}$ in the early stage of adipogenesis. Silibinin statistically significantly inhibits intracellular lipid accumulation and the mRNA expression of various genes involved at different stages during adipogenesis. Silibinin also suppresses expression of lipoprotein lipase (LPL), fatty acid binding protein 4 (AP2), and adiponectin in 3T3-L1 adipocytes. Thus, the anti-adipogenic effect of silibinin seems to originate from the ability to inhibit the expression of $C/EBP{\beta}$ and $C/EBP{\delta}$. Furthermore, silibinin decreases cell viability for differentiation period and induces apoptotic cell death through capspase-3 activation.