• Journal of Forest and Environmental Science
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• v.11 no.1
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• pp.61-71
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• 1995

From Salix maximowiczii of the Korean Salix, morphological and palynological characters were investigated by stereoscopic, light, and scanning electron microscopes. Also, this study was eonducted to investigate the effect of meteorological factors on the disjunct distribution in Salix maximowiczii forests grown within the restricted region. 1. Morphological characters of S. maximowiczii clarified with the descriptions and figures. 2. The palynological description was made to the S. maximowiczii and identified distinctly species. 3. S. maximowiczii is distributed only in Baekdam and Hangyeryong valley of Mt. Sorak in Kangwon-do, and valley of height region in Kyeongseong-gun (Hamgyongbuk-do), Sinhueng-gun, and Pungsan-gun (Hamgyongnam-do) in North Korea. 4. Water factors was better than temperature factors in the influence of meteorological factors for disjunct distribution. 5. These ecological and taxonomical informations could be used in practical application for silvicultural prescription, such as erosion control forest, timber production, and development of green area in river bank.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.1
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• pp.315-321
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• 2016

Background: Herbal medicine has becoming a potential source of treatment for different types of cancer including breast cancer. It has been shown that plants from the family Rhamnaceae possess anticancer activity. Objective: In this study, we determined the antiproliferative influence of Ziziphus spina christi- a species from this family- on the MCF-7 (human breast adenocarcinoma) cell line. Materials and Methods: The cytotoxicity of the total extract, ethanol, ethanol-aqueous (1:1) as well as aqueous fractions of Ziziphus spina christi leaves was evaluated through MTT assay against MCF-7 cell line. Cell cycle inhibition and apoptosis induction were assessed by flowcytometry cycle RNase/PI analysis and Annexin V-FLUOS, respectively. Apoptosis was also analyzed by immunoblotting assay. Results: Our results indicated that the ethanolic fraction had the lowest $IC_{50}$ value (0.02 mg/ml), induced cell cycle arrest at the G1/S phase as well as apoptosis after a 48h of treatment. Conclusions: This is the first report on anticancer effect of Ziziphus spina christi ethanolic fraction on breast cancer cells, providing a scientific basis for its utility in traditional medicine. However, further in-depth studies are needed to confirm the precise mechanisms.

• BMB Reports
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• v.36 no.4
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• pp.337-343
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• 2003

Rhus verniciflua Stokes (RVS) has been used as a traditional herbal medicine. Several earlier studies indicated that an ethanol extract of RVS has both anti-oxidant and anti-tumor properties, although the mechanism for the activity remains to be elucidated. In this report, we prepared a highly purified ethanol extract from RVS, named REEE-1 ($\underline{R}$hus $\underline{e}$thanol $\underline{e}$luted $\underline{e}$xtract-1), and investigated the mechanism involved in its growth-inhibitory effect on the human B and T lymphoma cell lines, BJAB and Jurkat, respectively. Results from tritium uptake proliferation assays showed that the proliferative capacities of both BJAB and Jurkat cells were strongly suppressed in the presence of REEE-1. This was further confirmed through trypan blue exclusion experiments that revealed a dose-dependent decrease in viable cell numbers after REEE-1 treatment. REEE-1-mediated suppression of cell growth was verified to be apoptotic, based on the increase in DNA fragmentation, low fluorescence intensity in nuclei after propidium iodide staining, and the appearance of DNA laddering. In particular, REEE-1 exerted its anti-oxidant activity through the inhibition of hydroxyl radical-mediated degradation by iron ion chelation rather than direct scavenging of hydroxyl radicals. Furthermore, REEE-1 was revealed to be a potential scavenger of superoxide anions. Collectively, our findings suggest that REEE-1 is a natural anti-oxidant that could be used as a cancer chemo-preventive and therapeutic agent.

• Journal of Wetlands Research
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• v.22 no.3
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• pp.217-224
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• 2020

Waterlogging and unintended lake formation become the main problem in some parts of the world. Starting from 1989, the waterlogging problem was observed in the farmland of the Jarso community of Konso Woreda adjacent to the Segen River in Ethiopia. Therefore, the objectives are determining the extent and causes of unintended lake formation using GIS/RS in addition to a preliminary field survey to mitigate the problem. The analysis of satellite images revealed that over the years invasion of the irrigable land by unwanted water had increased, as, in 1989, the size of the wetland area was about 8 Km²; in 2000 the size of the un-intended lake was only 8.23 ㎢. Alarmingly the size of the lake increased to 19.68 Km² in 2014. Silting up of Weir and changing the flow of River Segen and Human Intervention and changing the natural flow of River Yanda were the main causes of this unwanted prolonged water-logging. The ecological and social environment has been degrading as the people of the waterlogged area have been experiencing some settlement and losing their land. Another problem encountered was flooding from River Barka and invasion of the farmland. Sediment control best management practices (BMPs) i.e, Removal of sediment, providing sandbags and well-scheduled maintenance; Changing the junction point of Yanda and Segen River were suggested for the long-term and short term possible remedial measures. Gabion retaining wall on the bank of the Segen River to the face of Barka River was suggested to protect the farmland from flooding.

• The Korean Journal of Financial Management
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• v.22 no.2
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• pp.213-226
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• 2005

Adverse selection is a heavily scrutinized subject within the financial intermediary industry. Consensus is reached regarding its effect on the loan interest rate. Despite the similar features of financial service offered by the credit card, we still have controversy regarding credit card interest rate on how is adverse selection incurred with the change of interest rate. Thus, this paper explores how does the adverse selection, if ever, take place and affect the credit card interest rate. Information asymmetry regarding the credit card users' type represented by the default probability is assumed. The users are assumed to be rational in that they want to minimize the per unit dollar expense associated with the commercial transaction and financing between the two typical payment methods, cash and credit card. Suppliers, i.e. credit card companies, would like to maximize their profit and would be better off with more pervasive use of credit cards over the cash. Then we could show that the increasing credit card interest rate is subject to the adverse selection, sharing the same tenet with that of the bank loan interest rate proposed by Stiglitz and Weiss. Hence the current theory predicts that credit card market also suffers from adverse selection with increasing interest rate.

• The Journal of the Korea Contents Association
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• v.15 no.6
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• pp.411-420
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• 2015

With the rapid increase in the price of house lease, a unique housing form in Korea, a serious social issue has been raised as to the use value of house lease and residence stability of the ordinary people. This study thus aimed to analyze the direct factors that affect lease guaranteed loan and market volatility in order to explore the right direction of financial policy to reduce housing burdens. To this end, the direct variables affecting house lease guaranteed loan, including lease price, transaction price and lending rate, were defined. Vector Error Correction Model (VECM), a time series analysis, was employed to dynamically explain the data. Based on the house lease prices and bank data on loans between January 2010 and December 2014, it was found that the increase in lease price was the direct result of the increase in lease guaranteed loan, not that of the decrease in lending rate or increase in housing transaction price.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.1
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• pp.77-88
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• 2015

Soil column experiments were evaluated effects of silver nanoparticles (i.e., 0, 2.5, 5, and 10 mg/L) on the microbial viability which is strongly associated with the degradation of organic matter, pharmaceutically active compounds(PhACs) and biological oxidation of nitrogenous compounds during river bank filtration. The addition of silver nanoparticles resulted in almost no change in the aqueous matrix. However, the intact cell concentration decreased with addition of silver nanoparticles from 2.5 to 10 mg/L, which accounted for 76% to 82% reduction compared to that of control (silver nanoparticles free surface water). The decrease in adenosine triphosphate was more pronounced; thus, the number and active cells in aqueous phase were concurrently decreased with added silver nanoparticles. Based on the florescence excitation-emission matrix and liquid chromatograph - organic carbon detection analyses, it shows that the removal of protein-like substances was relatively higher than that of humic-like substances, and polysaccharide was substantially reduced. But the extent of those substances removed during soil passage was decreased with the increasing concentration of silver nanoparticles. The attenuation of ionic PhACs ranged from 55% to 80%, depending on the concentration of silver nanoparticles. The attenuation of neutral PhACs ranged between 72% and 77%, which was relatively lower than that observed for the ionic PhACs. The microbial viability was affected by silver nanoparticles, which also resulted in inhibition of nitrifiers.

• Journal of Korea Water Resources Association
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• v.46 no.7
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• pp.707-717
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• 2013

Channel-bed of erosion and sedimentation, where eroded bed and bank materials re-deposit through the action of flow, is a natural phenomenon in alluvial systems. Analysis using a numerical model is important to understand the sediment transport mechanism associated with erosion and sedimentation near weirs and other hydraulic structures within riverine systems. The local riverbed change near a hydraulic structure (Changnyong-Haman multi-function weir in Nakdong river) has been analyzed in order to examine the effect of hydraulic structure on local bed change. A 2D numerical model (CCHE-2D) has been implemented to simulate the sedimentation and erosion over a reach (10 km) including the weir. For the calibration and verification of the model, the rainfall data from a real event (Typoon 'Maemi' in 2003) has been used for flow and stage simulation. And the simulated results show a good agreement with the observed data for whole domain. From the result, it was found that the installation and operation of weir can aggravate the local bed change caused from the flow field change and resulting redistribution of sediment.

• Journal of Korea Water Resources Association
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• v.31 no.1
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• pp.85-93
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• 1998

This study is to analyze and predict the contaminant transport based on the hydrauli characteristics using 2-dimensional finite element model. The dynamic wate quality model. RMA-4. is used to predict the contaminant transport using the hydrulic characteristics obtained from RMA-2v model. The study region is from downstream of Cham-sil weir to upstream of Shin-Kok weir. From the results of contaminant transport analysis. it is shown that the variations of discharge and velocity give quite large effect to the transport and dispersion of contaminant material. and that the water qualities of Joong-Rang and Tan streams play an important role to the downstream also. when the incidental contaminant accident occurs and contaminant material moves to the downstream. it is resulted the decreasing of the maximum COD and the increasing of the duration time to be affected by contaminant. Finally. 2-dimensional analysis is required in the case of large river like Han River. since the large difference of contaminant concentration has been investigated in the left and right bank.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5274-5280
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• 2013

The aim of this study is to analyze the general satisfaction of the commercial areas near Cheonan central bus terminal and the rail-station and to extract various environmental factors of the city center which give effect to the user satisfaction of commercial area. As the result of the analyses, the environmental factors of the city center make a difference between the commercial areas of Cheonan central bus terminal and of the station in the aspects of user satisfaction. The user satisfaction of the commercial areas is appeared highest in 'comfort of walking environments' and 'convenience of commerce business transaction' which were environmental factors of the city center. For reactivation of the commercial area near Cheonan rail-station are needed improvement of walking environments and relocation of facilities as complex mall and bank etc.