• Applied Microscopy
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• v.29 no.1
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• pp.57-66
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• 1999

The nervous tissue in the cerebral ganglion of Korean planaria was observed using electron microscope. The obtained results are as follows: A cerebral ganglion is composed of the nerve cells, neurosecretory cells, neuroglial cells and neuropils. The nerve cells are round or ovoidal-shaped cells (diameter, $5{\mu}m$), which has a large ellipsoidal nucleus containing the evenly developed heterochromatin. Their cytoplasms were found to be relatively simple, because of their undeveloped cell organelles. The neurosecretory cells are long and ellipsoid or spindle-shaped cells, where there were found a large ellipsoidal nucleus and cytoplasm filled with secretory granules (diameter, 60 nm). The neuroglial cells were seldom observed. They are spindle-shaped cells (size, $6\times0.8{\mu}m$), which were observed mainly among the nerve fibers. The neuropils are formed by the nerve fibers and nerve endings which are filled with mitochondria, neurotubules and secretory granules of four kinds (high electron dense granules of sizes 75 nm, 50 nm and 37 nm, and electron lucent granule of size 30 nm etc.). These granular vesicles are divided into single vesicle type and compound vesicle type in the nerve terminals, and neuronal synapses were observed to be the axo-dendritic and dendro-dendritic synapse type.

• Journal of fish pathology
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• v.13 no.2
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• pp.129-136
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• 2000

To understand host-defence mechanism of clam(Ruditapes philippinarum) hemocyte against foreign materials, classification and their seasonal change in the number were performed. clams collected from a farm in Julpo Bay, Gochang, Chollabuk-Do were used in this experiment. Lots of hemocytes were found between the muscle fibers and connetive tissue of posterior adductor muscle. Hemocytes of R. philippinarum were classified into granulocytes and agranulocytes. Granulocytes were composed of three types, basophilic granulocyte, acidophilic granulocyte and fibrocyte in accordance with the staining affinities of their cytoplasmic granules. Fibrocyte has filopodia and vesicle in endoplasm and bigger than other granulocytes in size. Agranulocytes were less in the number and smaller in the size compared to those of granulocytes. Hyalinocytes had no granule in their cytoplasm. The nucleus located in the center of the cell was oval or spherical shaped. In electron microscopic observation, granulocytes and hyalinocytes contained electron-dense vesicles and some small lucid vesicles in their cytoplasm, respectively. Granulocytes phagocytosed more zymosan particles than hyalinocytes. Acidophilic granulocytes showed higher phagocytic ratio than basophilic granulocytes. Total hemocyte numbers showed the highest at April to August and the lowest at October to December. In the composition of each hemocyte, basophilic granulocytes were always more than acidophilic granulocytes and hyalinocytes.

• Applied Microscopy
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• v.34 no.1
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• pp.31-42
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• 2004

Acute respiratory distress syndrome (ARDS) is a kind of acute lung injury characterized by inflammatory disruption of alveolar-capillary barrier and notorious for its high mortality. Neutrophils cause cell damage through the production of free radicals, inflammatory mediators, and proteases in ARDS. $PLA_2$ might serve a primary regulatory role in the activation of neutrophils. This present study was performed to elucidate the effect of rutin known as $PLA_2$ inhibitor on ARDS induced by endotoxin. Endotoxin had increased lung myeloperoxidase (MPO) activity, BAL (bronchoalveolar lavage) protein content, numbers of neutrophils in BALF (bronchoalveolar lavage fluid) compared with those of control rat (p<0.001). In addition, histological evidence of lung injury was correlated with neutrophil influx into alveolar space and cerrous perhydroxide granules were found in lining of endothelial cell, alveolar type I, II cells. In contrast, pretreated group of rutin had significantly decreased all of the parameters (p<0.001). These data suggest that inhibition of $PLA_2$ is one step approach that block the process of ARDS. Accordingly, we conclude that rutin can be used as the prophylactic agent for ARDS on the bases of these experimental results.

• Economic and Environmental Geology
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• v.29 no.1
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• pp.65-75
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• 1996

Sulfate reduction and the precipitation of metal sulfides may have great potential to improve water quality of mine effluents in wetland treatment systems. Laboratory experiments using sulfate reducing bacteria (SRB) and limestone to treat effluents from the abandoned Dalsung tungsten-copper mine show that encouraging results, that have been attributed to sulfate reduction. Fe, Al, Cd, Cu and Zn are reduced to below detection limits with $99{\sim}100%$ metal removal rates, Mn is reduced by at least 90% to below 8.0 mg/l, and the pH is raised from 5.12 to 7.60 after 53 days of experiments. In the staged design, laboratory experiments are initiated to determine what would be reasonable substrate materials for remediation of the mine effluents. A substrate mixture containing 70% oak compost and 30% mushroom compost maintains $0.03{\sim}0.04mM$ of lactate, which provides good condition for the SRB granule. A downflow SRB wetland system is proposed as follows : 1) The lower part of the treatment system consists with a 25 cm thick layer of high quality (above 95% of $CaCO_3$) of limestone; 2) The geotextile (geonet) is recommended to be spread on the limestone bed to prevent clogging the limestones with the substrates; 3) The mixture of substrates with 70% oak and 30% spent mushroom composts, and SRB granules overlain on top of the geonet with 25 cm height. The sizes of the passive treatment systems are calculated according to metal loading and permeability criteria : 1) $220m^3$ ($15{\times}15{\times}1m$) for -1 level effluents; 2) $28m^3$ ($5.3{\times}5.3{\times}1m$) for -2 level; and 3) $2700m^3$ ($52{\times}52{\times}1m$) for the -3 level. The -3 level system needs to be broken down into 5 to 15 cells.