[Object] Gamma-Amino Butyric Acid (GABA), a four-carbon non protein amino acid, is widely distributed in nature and acts as the major suppressive neurotransmitter in the mammalian central nervous system. Recently, GABA has been reported to have several physiological functions such as antihypertensive, diuretic, relaxing and antidiabetic effects. Due to these unique biological functions, GABA has been used as functional ingredients for functional foods. Glutamic Acid Decarboxylase (GAD), which catalyzes decarboxylation of L-glutamic acid to GABA, has been purified from mammals, higher plants, and some microorganisms and their properties have already been reported. On the other hand, mushrooms are commonly appreciated as healthy food due to their nutritional properties, such as low calorie, rich in fiber, vitamin and mineral. L-Glutamic acid and GABA are also commonly distributed in edible mushrooms. The fact that mushrooms accumulate GABA suggests the existence of GAD. However, the enzyme property of mushroom GAD has not been reported. In the present study, we tried to evaluate the property of Flammulina veltipes GAD, and the purification and characterization of enzyme is also investigated. [Methods and Results] Mushroom (fruit-body of Flammulina veltipes) used in this study was purchased in local market. GAD activity was determined by formation of GABA from L-glutamic acid in the presence of pyridoxal-5’- phosphate (PLP). The activity of enzyme was determined semi-quantitatively by color intensity of GABA on TLC analysis. Fruit-body was crushed and then centrifuged to separate supernatant and precipitate. To investigate the location of GAD, both supernatant and precipitate were subjected to enzyme reaction after dialysis. The enzyme activity of precipitate is stronger than that of supernatant. The formation of GABA was observed between pH 4 and 6 and the maximum color intensity of GABA was observed at pH 6. However, GAD activity was lost after dialysis for overnight against buffer of pH 6-11. These results suggest that GAD from Flammulina veltipes is stable at pH 4-5 in spite of its optimum pH for GABA production is around 6.

Compositional dependence of corrosion behavior of rapidly solidified Mg-rich Mg-Zn-Y alloys in NaCl aqueous solution has been investigated. Mg-Zn-Y ternary alloys containing small amounts of Zn exhibited low corrosion rate, although the (at. %) binary alloy showed severe corrosion with violet evolution of hydrogen. The alloy with highest corrosion-resistance was , its corrosion rate was about 1 mm year-1 in 0.17 M (1.0 wt. %) NaCl solution. alloy exhibited passive region in anodic polarization curves when immersed in NaCl solution. Rapidly solidification and small amount of Zn addition may bring about an increase in electrochemical homogeneity of Mg-Zn-Y alloys, resulting in enhancement of corrosion resistance.

From a viewpoint of heat stress at high temperatures and contact thermal resistance, it is confirmed that the optimal structure is the skeleton structure using Cu substrate on the cooling side, which has excellent heat conductivity and the optimal installation method is to adopt a carbon sheet and a mica sheet to the high temperature side, where Si grease is applied to the low temperature side, under pressurized condition. The power of the developed modules indicated 0.5W in an module and 3.8 W with a SiGe module at 823K, respectively.

The resources conservation system is comprehended, making Taean-haean National Park a research material by applying the fact of landowning, designating an LOP and Korea and Japan's Natural Park Act. Following conclusions were obtained in this study; Most of land areas of the National Park are privately owned; Only a few have been designated as Natural Reservation, a core reserved area on LOP, and a sandy beach, a sand dune, a sand spit, a tidal flat, a wetland, etc are distributed in the natural environment area so they were exposed to development; As seen in most of coastal type of National Parks, 13 commercial beaches are established. The annual rush to the beaches appears in July and August; Sand dune areas that have to be managed in terms of conservation, are turned into beaches. Moreover, the collective facilities areas are randomly developed. So they fail to function originally; The current Natural Park Act has no systematic devices for conservation of the natural resources on the seashore or offshore.