• Journal of Astronomy and Space Sciences
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• v.24 no.2
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• pp.125-134
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• 2007

In this paper, we analyze the orbital variation of the Korea Multi-Purpose SATellite-1(KOMPSAT-1) in a strong space environment due to satellite drag by solar and geomagnetic activities. The satellite drag usually occurs slowly, but becomes serious satellite drag when the space environment suddenly changes via strong solar activity like a big flare eruption or coronal mass ejections(CMEs). Especially, KOMPSAT-1 as a low earth orbit satellite has a distinct increase of the drag acceleration by the variations of atmospheric friction. We consider factors of solar activity to have serious effects on the satellite drag from two points of view. One is an effect of high energy radiation when the flare occurs in the Sun. This radiation heats and expands the upper atmosphere of the Earth as the number of neutral particles is suddenly increased. The other is an effect of Joule and precipitating particle heating caused by current of plasma and precipitation of particles during geomagnetic storms by CMEs. It also affects the density of neutral particles by heating the upper atmo-sphere. We investigate the satellite drag acceleration associated with the two factors for five events selected based on solar and geomagnetic data from 2001 to 2002. The major results can be summarized as follows. First, the drag acceleration started to increase with solar EUV radiation with the best cross-correlation (r = 0.92) for 1 day delayed F10.7. Second, the drag acceleration and Dst index have similar patterns when the geomagnetic storm is dominant and the drag acceleration abruptly increases during the strong geomagnetic storm. Third, the background variation of the drag accelerations is governed by the solar radiation, while their short term (less than a day) variations is governed by geomagnetic storms.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.6
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• pp.759-767
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• 2014

This study examined the effect of Momordica charantia L. (bitter melon: BM) on lipid and hepatic antioxidative enzyme levels in diabetic rats. Diabetes mellitus was induced in male Sprague-Dawley rats by injection of streptozotocin (STZ), and rats were fed for 4 weeks with experimental groups divided into four groups: a normal control group, STZ-control and STZ-BM 5% & STZ-BM 10% treated groups. Levels of free fatty acids (FFA), high-density lipoprotein cholesterol (HDL-chol), triglycerides (TG) in plasma and malondialdehyde (MDA) & protein in liver, catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), and xanthine oxidase (XOD) were measured in liver cytosol. Level of HDL-chol significantly increased in the STZ-BM 5% diabetic group. TG & FFA levels were significantly higher in all diabetic groups compared to the control group. MDA and protein levels were significantly higher in the STZ-BM 5% group compared to all other experimental group. CAT level was higher in the supplementary group with BM compared to the STZ-control group, although the difference was not significantly different. SOD level was not significant in any experimental groups. GST level was significantly higher in the BM-treated groups compared to the STZ-control group. XOD level was significantly lower in the BM 5% group and significantly decreased in all experimental groups. These results show that supplementation of BM fruit powder may have beneficial effects on diabetic complications and damage caused by oxidative stress.

• Journal of Life Science
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• v.23 no.12
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• pp.1454-1459
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• 2013

This study investigated the effects that water temperature and the administration of estradiol-17${\beta}$ (E2) had on the sex ratio and growth of the Japanese eel, Anguilla japonica. Glass eels (total length${\fallingdotseq}$6.5 cm) were differentiated into an E2 group and an E2-free group and then they were reared for about four months at three water temperature levels of $20^{\circ}C$, $24^{\circ}C$, and $28^{\circ}C$. The results showed that the young eels survived normally at the rearing water temperature of ${\geq}24^{\circ}C$, and grew to a mean size of 20 cm (total length). In the E2-free group, temperature was not found to increase the sex ratio (feminizing rates); however, the sex ratio of the E2-administrated group was found to be a little higher at a high temperature ($28^{\circ}C$). The growth of the E2 group was lower than the growth of the E2-free group at $24^{\circ}C$ and the E2 concentration levels in the plasma at $24^{\circ}C$ were found to be significant after the end of the E2 administration period (178 days). Therefore, we thought that long-term administration of E2 must be considered to be the reason for growth decline in spite of the prominent sex ratio effect. Our results indicate that temperature was not related to an increase in the feminizing rate (sex ratio) in the Japanese eel, Anguilla japonica, and other environmental factors (rearing density, salinity, etc.) that have the possibility of inducing ovarian differentiation must be investigated.