• Polymer(Korea)
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• v.39 no.1
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• pp.56-63
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• 2015

The object of this study is to prepare microcapsules containing a diisocyanate compound, apply them to self-healing protective coating, and evaluate the self-healing capability of the coating by atmospheric moisture. Isophorone diisocyanate (IPDI) polymerized under humid atmosphere, indicating that IPDI can be used as a healing agent. Microencapsulations of IPDI were conducted via interfacial polymerization of a polyurethane prepolymer with diol compounds. The formation of microcapsules was confirmed by Fourier-transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. The mean diameter, size distribution, morphology and shell wall thickness of microcapsules were investigated by optical microscopy and scanning electron microscopy (SEM). The properties of microcapsules were studied by varying agitation rates and diol structure. The self-healing coatings were prepared on test pieces of CRC board. When scratch was generated in the coatings, the core material flew out of the microcapsules and filled the scratch. The self-healing coatings were damaged and healed under atmosphere with 68~89% relative humidity for 48 h, and SEM and impermeability test for the specimens showed that the scratch could be healed by atmospheric moisture.

• Parasites, Hosts and Diseases
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• v.27 no.4
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• pp.253-260
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• 1989

Metacercariae of the genus Stictodora encysted in the head tissue of Acanthogobius navimanus (the gobies) caught at Sachun-gun, Kyongnam Province, were identified to be Stictodora Zari Yamaguti, 1939 (Trematoda: Heterophyidae), a new parasite fauna in Korea. The metacercariae were 0.39∼,0.43 mm by 0.32∼0.35 mm in size, long elliptical, and with a thin and transparent cyst wall. Total 200 metacercariae were collected from 50 gobies. In order to obtain adult worms two kittens and a Puppy were infected each with 34∼100 metacercariae, and total 33 adults were recovered between the day 4 and day 8 post-infection. The S. sari adults measured 0.95∼1.18 mm long and 0.26∼0.32 mm wide and the eggs in uteri 0.028∼0.033 mm by 0.017∼0.020 mm. The most characteristic morphological feature of these flukes was the presence of a gonotyl and gonotyl spines arranged in two groups; densely crowded group of 30~40 spines and linearly-arranged one of 30∼40 spines, together of which made a comma(or reversed comma) shape along the lateral margin of the gonotyl. It has been proved by this study that 5. sari is distributed in southern coasts of Korea.

• Korean Journal of Plant Taxonomy
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• v.42 no.4
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• pp.247-252
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• 2012

Seed morphology in the subtribe Agrimoniinae (Rosaceae) was examined using scanning electron microscopy to identify distinct characters and evaluate their evolution in a phylogenetic framework for five genera in the subtribe: Agrimonia L., Aremonia Neck. ex Nestl., Hagenia J.F. Gmel., Leucosidea Eckl. & Zeyh., and Spenceria Trimen. All genera have one or two mature achenes in a fruiting hypanthium. In the seed coats, the cell shape, size, wall features, and sculpturing vary across genera. Of most significance is the presence of papillae structures in both Agrimonia and Aremonia. Through the mapping of papillae features onto phylogenetic trees, either one or two changes in seed coats are hypothesized. The phylogenetic tree inferred from four nuclear and six chloroplast regions of sequence data suggests that at least two steps of papillae sculpturing on seed coats are required. On the other hand, in the phylogenetic tree of a low-copy nuclear gene, one independent evolutionary step is postulated to explain the current character states. In the latter hypothesis, the seed coat sculpturing also supports a monophyletic relationship for cosmopolitan Agrimonia and European endemic Aremonia. The seed coat sculpturing provides valuable information for inferring phylogenetic relationships at the generic level in the subtribe Agrimoniinae.

• Food Science and Preservation
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• v.13 no.3
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• pp.397-403
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• 2006

This experiment was conducted to examine the changes in polysaccharide concentration and morphological variation of Fomitopsis pinicola mycelium during submerged-culture in the citrus peel medium (CP). On the 12 days culture, the yields of mycelium and alcohol insoluble substance were 40.21%(w/v) and 6.94%(w/w), respectively, which were much higher than 11.29%(w/v, wet basis) and 3.17%(w/w, wet basis) obtained from YM medium. A large amount of acid soluble polysaccharides was derived from YM medium while a larger amount of alkali soluble polysaccharide was produced from CP medium. Yields of the mycelium were higher when cultured in CP medium However, there was no significant difference in formation of membranous vesicle between mycelia cultured in CP medium and YM medium. It was also observed that the formation of vacuole was closely related to the activation of the multivescular body known as cytolysome. As a result activation of mycelium and cell wall biosynthesis were more accelerated in CP medium.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.2
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• pp.209-222
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• 1997

Authors surveyed the ground water near the waste disposed from a fiberglass production factory to confirm the presence of glassfiber in the water and to determine the effect of sampling conditions and storage on the recovery of fibrous materials in the ground water. Sample was collected at every 4 hours for 48 hours consecutively. After finishing the 48 hours sample, water sampling was done from each tap after repeated turning on and off the water for 30 seconds at each time. Sample was collected in the two 1.5 liter polyethylene bottle after vigorously shaking the bottle with the same water several times with the flowing tap water. At each paired sample, one bottle was stored stand still at room temperature, and the other sample was filtered immediately after sampling. Water was filtered on the Mixed Cellulose Ester filter with negative pressure. Each sample was divided into upper and lower layer. The other bottle was stored at room temperature standstill for 7 days and filtered in the same fashion as the other pair of sample did. Each MCE filter was divided into 4 pieces and one piece was treated with acetone to make it transparent. Each prepared sample was observed by two researchers under the light and polarizing microscopy, scanning electron microscopy and energy dispersive X-ra microanalysis. Fibers were classified by the morphology and polarizing pattern under the polarizing microscope, and count was done. 1. There was a significant fluctuation in number of the fibers, but there was no specific demonstrable pattern. 2. Non-polarizing fibers frequently disappeared after 7 days's storage. But cluster of fibers were found at the wall of the same container by scratching technique. 3. Polarizing fibers were usually found in between the filter and the manicure pasted area. Possible explanations for this phenomenon will be that either these fibers are very light or have electronic polarity. Hence, these fibers are not able to be attached on the surface of slide glass. 4. Under the scanning electron microscopic examination, the fibers which are not refractive under the light microscopy were identified as glassfiber. Other fibers which is refractive under the polarizing microscopy were identified as magnesium silicate fibers. It is strongly suggested that development of standardized method of sample collection and measurement of fibrous material in the water is needed.

• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.41-47
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• 2003

This study was conducted to investigate the in vivo and in vivo antibiotic effect of crude fucoidan extracted from Hizikia fusiforme, and to investigate any possible structural changes of broiler chick's intestinal villi by the supplementation of fucoidan. Total 84 broiler chicks were randomly assigned to 7 treatments, control and Salmonella typhimurium infection groups. The broiler chicks was infected with Salmonella typhimurium at third days, and antibiotics, fucoidan, dried Hizikia fusiforme, dried Undaria pinnatifida and yeast cell debris was respectively supplemented for each group. Each treatment had 4 chicks with three replications. Extraction yield of crude fucoidan from Hizikia fusiforme was 5.453%. Antibiotic effect of fucoidan was not detected in vitro, inhibition zone and micoorganism growth test. Weight gains of broiler chicks were tend to higher in fucoidan treatment group and yeast cell significance was not found. In in vivo test, the number of viable Salmonella typhimurium was low in the antibiotics and fucoidan treatment groups. The intestinal villi were short in the fucoidan and marine algae treatment groups. The intestinal villi were densely distributed on the large intestinal wall, but the morphology was not different among treatments.

• Parasites, Hosts and Diseases
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• v.36 no.2
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• pp.81-90
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• 1998

The present study was performed to observe the infection status of several kind of animals with indigenous Gnnthostomn in Korea, and morphological characteristics of gnathostome larvae detected from pit-viper, Askistronon breuiccudus, for the species bullfrogs. several kinds of snakes, j.e., 55 Elnphe rufodorsata, 2 Dinodon rufozonatum rufzonatum. 62 Rhnbdophis tisrinus tigrinus and 87 Askistronon app., and 438 cats were examined. A total of 21 larval gnathostomes was detected from 12 pit-vipers, A. breuicnudus. They were 2.233 x 0.343 mm in average size and covered with about 210 transverse rows of minute cuticular spines. Their characteristic head bulbs were provided with 4 rows of hooklets of which average numbers in each row were 36.8, 39.0, 41.7 and 44.3. posteriorly. In the cross sections of midgut level, the intestinal wall consisted of a single layer of 19-25 elongate epithelial cells with a single nucleus. SEM observation of the larvae revealed unique features of head bulb , cuticular spines on transverse striations and a cervical papilla. On the basis of above morphological characteristics, they were identified as the advanced third-stage larvae of Gnothostomo hispinum. It was first confirmed that the pit-viper. ABkistronon breuicaunus is the snake intermediate host of G. hispidun.

• Korean Journal of Medicinal Crop Science
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• v.9 no.4
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• pp.251-258
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• 2001

Medicinal plant extracts including Rubus coreanus, Sanguisorba officinalis, Eriobotrya japonica, Prunus mume, Crataegus pinnatifida, Rosa leavaigate Prunus persica, Prunus japonica var. nakaii and Spiraea blumei were prepared for the test of antibacterial activity. Tryptic soy broth (TSB) containing $0{\sim}10mg/ml$ of medicinal plant extracts was inoculated with $10^6$ cells/ml of Staphylococcus aureus and incubated at $35^{\circ}C$ for 24 hours. The plate counting method and clear zone test were used to test inhibitory effect of the extracts. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was derived from the survival curves of S. aureus. The order of antibacterial activities of medicinal plant extracts on the S. aureus was Rubus coreanus > Sanguisorba officinalis > Eriobotrya japonica > Prunus mume > Crataegus pinnatfida. Minimum inhibitory concentration of Sanguisorba ofEcmalis on the Staphylococcus aureus was 2.5mg/ml and minimum bactericidal concentration of Rubus coreanus was 1.0%. Inhibition zone of Rubus coreanus, Sanguisorba officinalis, Eriobotrya japonica, Prunus mume, and Crataegus pinnatifida was 16.5mm, 14.3mm 11.0mm, 14.0mm and 12.7mm, respectively. The morphology of S. aureus cells treated with medicinal plant extracts showed damage of cell wall and cytoplasmic membrane. Severely damaged cells of S. aureus lost electron dense material and cytoplasm. This result suggests that medicinal plant extracts can be used as an effective natural antibacterial agent in food.

• Journal of Veterinary Clinics
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• v.37 no.5
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• pp.242-248
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• 2020

An intestinal strigeiid trematode, Apharyngostrigea pipientis, was detected from Ardea cinerea jouyi, Egretta intermedia and Nycticorax nycticorax between July, 2006 and June, 2020 in Daejeon metropolitan city and Kangwon-do, Republic of Korea. It was observed with a light and scanning electron microscope (SEM), and molecularly analyzed with 18S rRNA genes. The infection rate of the strigeiid trematode was 25.9% (7/27). The body is cylindrical in whole mount, greatly elongated in outline and shows a strong dorsal curvature. The overall measurements are: length 4.1-4.8 mm; fore-body 1.00-1.20 mm by 0.8-0.9 mm; hind-body 3.2-3.6 mm by 0.43-0.46 mm. The body is covered by a relatively thick cuticle, devoid of spines. The oral sucker leads into a short esophagus that is devoid of a muscular pharynx. The holdfast organ is enormously developed. The vitelline follicles distributed dorsal wall of fore-body and hind-body. This strigeiid trematode especially differs from other species of genus Apharyngostrigea in morphology. Although these A. pipientis are several morphological distinctions from Apharyngostrigea cornu, the partial sequence of 18S rRNA showed the sequence homology of A. pipientis (99.9%) and A. cornu (99.8%), and this result revealed their conspecific relationship between A. cornu and A. pipientis. This is the first report of A. pipientis in the Republic of Korea.

• Journal of the Korean Geographical Society
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• v.33 no.3
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• pp.447-454
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• 1998

As a widespread tephra erupted 24 to 25 KA, Aira-Tn Ash, or AT, provides an invaluable datum for stratigraphic study of late Pleistocene in Northeast Asia. AT can be identified from their tonal characteristic and morphology (the so­called bubble-wail feature), as well as typical refractive index. First reported in 1983, its presence was confirmed from many palaeolithic deposits distributed throughout Korea. It forces us to reconsider the age of prominent Pleistocene deposits. At the famous archaeological site of Chon-gok-ni, presence of AT lends a firm support that sedimentation and deposition of lithic assemblage were in fact a late Upper Pleistocene event, thus, throwing a new question at archaeologists to explain why such archaic-looking tools were continued to be made. Discovery of AT at Chongdongjin is more surprising, since the coastal terrace has been regarded by many as an early Lower Pleistocene eustatic feature. It implies strongly that we need to devise a new scheme for Quaternary stratigraphy. In the absence of reliable datum and marker for Quaternary research, efforts must be given to search for and identify AT and other widespread tephras.