• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.69-80
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• 2007

Among the photoactive semiconductors such as $TiO_2,\;ZnO,\;Fe_2O_3,\;WO_3,\;and\;CdSe,\;TiO_2$ is the most widely used as photocatalyst in different media, because of its lack of toxicity and stability. In this study, the effects of titanium dioxide were investigated to obtain the information of physiological change in rice plant. Light-adapted Chlorophyll flourescence index decreased and relative electron transport rate of rice leaves was activated by titanium dioxide under $2,400\;{\mu}mol\;m^{-2}\;s^{-1}$ PAR (Photosynthetic active radiation). Relative electron transport rate of rice leaf treated with titanium dioxide 10 ppm was high in order of $2,400\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR,\;2,200\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR,\;450\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR$ and titanium dioxide 10 ppm (45.1%), control (32.4%), diuron 10 ppm (15.3%) under $2,400\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR$. Titanium dioxide increased photosynthesis of the rice leaf under $13.6\;KJ\;m^{-2}\;day^{-1}$ UV-B only. With titanium dioxide 20 ppm, reduced UV-B ($0.15\;KJ\;m^{-2}\;day^{-1}$) intensity changed the induction of proteins and twenty-five proteins were identified. Among them, seventy proteins were up-regulated, four proteins were down-regulated and four proteins were newly synthesized. Function of these proteins was related to photosynthesis (52%), carbohydrate metabolism (4%), stress/defense (8%), secondary metabolism (4%), energy/electron transport (4%), and miscellaneous (28%).

• Journal of Aquaculture
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• v.19 no.4
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• pp.247-253
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• 2006

This study was conducted to investigate the effects of dietary supplementation of ${\beta}-1,3$ glucan on growth and immune responses in juvenile olive flounder, Paralichthys olivaceus fed the white fish meal based diets for 6 weeks. Five experimental diets supplemented with ${\beta}-1,3$ glucan at 0, 0.01, 0.025, 0.05, 0.1 % (Control, $G_{0.01},\;G_{0.025},\;G_{0.05}\;and\;G_{0.1}$, respectively) of diet on a dry-matter basis. Five experimental diets were formulated to be isonitrogenous and isocaloric to contain 50.0% crude protein and 16.7 kJ available energy $g^{-1}$. Fish averaging $3.2{\pm}0.1\;g\;(mean{\pm}SD)$ were randomly distributed in each aquarium as triplicate groups of 15 fish. Weight gain (WG, %), specific growth rate (SGR, %), and feed efficiency (FE, %) of fish fed $G_{0.1}$ diet were found significantly higher than those of fish fed Control, $G_{0.01},\;G_{0.025}\;and\;G_{0.05}$ diets (P<0.05). However, there was no significant difference among the fish fed control, $G_{0.01},\;G_{0.025}$. Chemiluminescent responses (CL) of fish fed $G_{0.1}$ diet were significantly higher than those of fish fed the other diets. Serum lysozyme activities of fish fed $G_{0.05}$ and $G_{0.1}$ diets were higher than those of fish fed control, $G_{0.025}$ and $G_{0.05}$ diets. Fish fed $G_{0.1}$ diet showed a significantly lower cumulative mortality than did fish fed control diet throughout the challenge test (P<0.05). These results suggested that based on growth rate, feed efficiency, non-specific immunity and protection against microbial infections the optimum dietary ${\beta}-1,3$ gulcan could be greater than 0.05% but less than 1.0% in juvenile olive flounder, Paralichthys oilvaceus.

• Economic and Environmental Geology
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• v.22 no.1
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• pp.35-63
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• 1989

Geochemical characteristics of the Guryongsan (Ogcheon) uraniferous black slate show that this is an analogue to the conventional Chattanooga and Alum shales in occurrences. Whereas, its highest enrichment ratio in metals including uranium, among others, is explained by the cyclic sedimentation of the black muds and quartz-rich silts, and the uniform depositional condition with some what higher pH condition compared to the conditions of the known occurrences. The cyclic sedimentation, caused by the periodic open and close of the silled basin, has brought about the flush-out) of the uranium depleted water and the recharge with the new metal-rich sea water, which consequently contributed to the high concentration of metals in mud. The metal-rich marine black muds, which mostly occur in the early to middle Palaeozoic times, is attributed by the geologic conditions which related to the atmospheric oxygen contents, and these are scarcely met in the late Precambrian and/or with the onset of Palaeozoic era in the geologic evolution of the earth.