• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.2
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• pp.122-131
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• 2010

This paper introduces the concept of a virtual ecosystem and reports the following three mathematical approaches that could be widely used to construct such an ecosystem, along with examples: (1) a molecular dynamics simulation approach for animal flocking behavior, (2) a stochastic lattice model approach for termite colony behavior, and (3) a rule-based cellular automata approach for biofilm growth. The ecosystem considered in this study consists of artificial organisms and their environment. Each organism in the ecosystem is an agent that interacts autonomously with the dynamic environment, including the other organisms within it. The three types of model were successful to account for each corresponding ecosystem. In order to accurately mimic a natural ecosystem, a virtual ecosystem needs to take many ecological variables into account. However, doing so is likely to introduce excess complexity and nonlinearity in the analysis of the virtual ecosystem's dynamics. Nonetheless, the development of a virtual ecosystem is important, because it can provide possible explanations for various phenomena such as environmental disturbances and disasters, and can also give insights into ecological functions from an individual to a community level from a synthetic viewpoint. As an example of how lower and higher levels in an ecosystem can be connected, this paper also briefly discusses the application of the second model to the simulation of a termite ecosystem and the influence of climate change on the termite ecosystem.

• KSBB Journal
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• v.23 no.6
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• pp.529-534
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• 2008

The reactive oxygen species generated by ultraviolet rays causes various types of cutaneous damage, such as lipid peroxidation and denaturation of the extra-cellular matrix. The accumulation of such damage contributes to skin aging, especially the formation of wrinkles. This study was carried out to develop functional cosmatic by using Oriental herb supercritical extracts (OHSE) for prevention of skin. Effects of OHSE on anti-oxidation, collagenase inhibition and collagen synthesis in normal human fibroblast were investigated. OHSE showed antioxidative activity as high as vitamin C, trolox and DL-penicillamine. Also OHSE showed promotive effect on collagen synthesis and inhibitory effect on collagenase activity. From this results, we conclude that OHSE may have the potential to be conveniently used as an additive in cosmetics for prevention and improvement of skin aging.

• Parasites, Hosts and Diseases
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• v.28 no.1
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• pp.45-52
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• 1990

Intestinal histopathological changes due to infection with Echinostcma hortense (Trematoda) were studied in rats after experimental infection with the metacercariae. The metacercariae were obtained from the tadpoles of Rana nigrcmaculata, a second intermediate host infected in the laboratory. Total 18 albino rats(Sprague-Dawley) were given 200 matacercariae each and sacrificed on the day 1, 3, 7, 11, 22 or 44 post-infection(PI) Segments of- the small intestine at 1, 3, 5, 8 and 30 cm posterior to the pylorus(PTP) were rejected and studied histopathologically. 1. The flukes were seen to have intruded into the intervillous space in the upper small intestine at early stages(1∼3 days PI), however, they were located mainly in the intestinal lumen at later stages(7∼44 days PI) . The flukes were sucking and destroying the epithelial layers of villi with their oral and ventral suckers. 2. Histopathological changes of the intestine were recognizable in as early as 1∼3 days after infection, and the changes became severer as the infection progressed. 3. The intestinal mucosa was histopathologically characterized by villous atrophy and crypt hyperplasia throughout the infection period. Major villous changes were blunting, fusion, severe destruction and loss of epithelial layers of villi. Villous/crypt(V/C) height ratio was remarkably reduced from 3 : 1 in controls to 1 : 1 in severely infected animals. In the stroma of villi, inaamma- tory cell infiltrations, vascular congestion, edema, and/or fibrosis were recognized. The goblet cells were increased in number after 11 days PI. It was revealed in the present study that the pathological changes in the intestine of rats infected with E. hortense were chieay confined to the mucosal layer of the upper small intestine, however, the changes were very severe accompanying remarkable destruction of villi and loss of mucosal integrity, and persistent until 44 days PI.

• The Korean Journal of Mycology
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• v.35 no.2
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• pp.85-95
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• 2007

This study was carried out to investigate the physiological activities of the ethanol extract from Gymnopilus spectabilis mycelium (EGM) and of the supernatant obtained from fermentation broth (SGB). The contents of polysaccharides, phenol compounds and total ${\beta}-glucans$ of EGM were found to be 80.14%, 3.5 mg/ml and 5.91%, respectively and those for SGB were 78.68%, 3.32 mg/ml and 3.28%, respectively. Both EGM and SGB exhibited dose-dependent nitrate-scavenging abilities at pH 1.2. In addition, both EGM and SGB on the autoxidation rate of the linoleic acid demonstrated powerful antioxidant activities at 1 mg/ml level. With respect to fibrolytic activity, EGM showed 1,180 unit/g, which was the same activity as streptokinase, while SGB was 1,011 unit/g. The angiotensin converting enzyme inhibition activity of EMG determined by both the normal and pretreatment methods were estimated to be 8.2% and 10.2%, respectively. However, SGB showed no corresponding activity. The growth inhibitory effects of EGM on AGS, A549, HeLa and NCTC cells were over 58.88%, respectively. And the growth inhibitory effects of the SGB on HeLa and NCTC cells were 44.92 and 76.76%, respectively. Also, EGM and SGB activated the components of the alternative complement pathway from 51 and 62% at the concentration of 100 mg/ml, The xanthine oxidase inhibition activities of EGM and SGB (1 mg/ml) were 9.53 and 16.92%, respectively.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.97-97
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• 1993

Primary tumor arises infrequently in the parotid gland and generally, only about 20 to 40 percent of which prove to be malignant. They are characterized by histopathologic diversity, slow tumor growth, significant proportion of patients who have received previous treatment elsewhere. We have reviewed retrospectively 101 cases of parotid gland tumors which were treated for the recent eight years (1985-1992), Non-neoplastic tumor-like lesions were all excluded.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.27-33
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• 2012

Purpose: Most of diagnosis in the pediatric hydronephrosis patients have been performed $^{99m}Tc$-DMSA renal scan. Then the region of interest (ROI) is set for comparative analysis of uptake ratio in left-right kidney after acquiring the image. But if the equipment set an automatic ROI, the ROI could include expanded renal pelvis due to hydronephrosis and the uptake ratio of left-right kidney will be incorrect result. Therefore this study compared both ROIs including expanded renal pelvis and excluding renal pelvis through experiment using normal kidney phantom and expanded renal pelvis phantom and suggested setting method of improved ROI. In addition, this study have been helped by readout doctor for investigate distinction radiopharmaceutical uptake between renal cortex and remained urine by expanded renal pelvis. Materials and Methods: The both of renal phantoms were filled with water and shacked with $^{99m}TcO_4$ 111 MBq. In order to describe the expanded renal pelvis, the five latex balloon were all filled with 10 mL water and each of balloon was mixed with $^{99m}TcO_4$ 18.5, 37, 55.5, 74, 92.5 MBq. And we made phantom with fixed $^{99m}TcO_4$activity of 37 MBq and mixed water 5, 10, 15, 20, 25 mL in each balloon. The left kidney was fixed its shape and the right kidney was modified like as hydronephrosis kidney by attached the latex balloons. And the acquiring counts were 2 million. After acquisition, we compared the image of ROI with Expanded renal pelvis and the image of ROI without renal pelvis for analyzing difference in the uptake ratio of left-right kidney and for reproducibility, set the ROI 5 times in the same images. Patients were injected $^{99m}Tc$-DMSA 1.5~1.9 MBq/kg and scanned 3 to 4 hours after injection. The each of 3 skillful radio technologists performed the comparing estimation by setting ROI. To determine statistical significance between two data, SPSS (ver. 17) Wilcoxon Signed Ranks Test was used. Results: As a result of renal phantom's experiment, we compared with average of counts Background (BKG) ratios in the setting of ROI including expanded renal pelvis and setting of excluding expanded renal pelvis. Therefore, they can obtain changed counts and changed ratios. Patient also can obtain same results. In addition, the radiopharmaceutical uptake in expanded renal pelvis was come out the remained urine that couldn't descend to ureter by the help of readout doctor. Conclusion: As above results, the case of setting ROI including expanded renal pelvis was more abnormally increasing uptake ratio than the case of setting ROI excluding expanded renal pelvis in analysis the uptake ratio in left-right kidney of hydronephrosis. Because of the work convenience and prompted analysis, the automatic ROI is generally used. But in case of the hydronephrosis study, we should set the manual ROI without expanded renal pelvis for an accurate observation of the uptake ratio of left-right kidney since the radiopharmaceutical uptake in expanded renal pelvis is the remained urine.