• Membrane Journal
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• v.27 no.5
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• pp.389-398
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• 2017

The most important characteristic of the polymer electrolyte membranes (PEMs) for fuel cells, the proton conducting ability is mainly influenced by the distribution and morphology of the water channels inside the PEMs. Non-perfluorinated hydrocarbon PEMs are known to have weaker water channels than perfluorinated PEM, Nafion, and thus relatively low proton conducting ability. In this study, we used a mesoscale simulation technique to observe the water channel formation and phase separation behavior of hydrocarbon PEM, sulfonated polyimides, under the humidification condition. It was observed that the water molecules were distributed evenly through the entire hydrophilic region, and clear water clusters were formed only in the sulfonated polyimide having high sulfonation degree. In addition, it was observed that sulfonated polyimides have a difficulty in forming water channel under the low hydrated condition. These results clearly support the theories of the formation of water channels in non-perfluorinated hydrocarbon PEMs, and also well explain the tendency of proton conducting abilities of sulfonated polyimides. Thus, it is confirmed that mesoscale simulation techniques can be very effective in analyzing phase separation behavior and water channel formation in PEMs for fuel cells and elucidating the ion conducting abilities.

• Archives of Plastic Surgery
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• v.35 no.2
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• pp.139-146
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• 2008

Purpose: The objective of this study is anthropometric analysis of mouth and lower face of Korean. The relationship of soft-tissue to underlying bony structures determine the overall aesthetics of the face. The goal of aesthetic surgery of the face is to achieve the ideal normal and enhance the aging face. The purpose of present study was to determine the change of the morphology of the mouth and lower face based on soft-tissue landmarks according to age group to facilitate prediction during aesthetic surgery. Methods: The standardized photographs of 2,018 healthy volunteers(18 to 79 years of age; 1,070 males, 948 females) were investigated. Age groups were classified into young, middle-aged, and elderly groups. Five and seven items were measured on frontal and lateral view photographs, respectively. Individual dimensions were compared in the three age groups and between males and females. Results: The width of mouth is 4.5 times larger than that of philtrum. Most of measured data decreased with age. However, woman's lip width of the mouth somewhat increased from the young to elderly. The width of lower face is 2.5 times larger than mouth in young age group and increased slightly from the young to middle-aged and thereafter slightly decreased to elderly group. Upper lip was more higher than lower lip and male lip was more higher than female. But male and female lip height is similar at old age. Conclusion: Most of Koreans showed prominent lower face because of the development or protrusion of the mandible. And the descent of soft-tissue around the mouth was one of the significant characteristics of senile change. The posterior retrusion of the subnasal was an another characteristic. This study will help to elucidate the age-related dimensional differences of the human being and to provide useful information for clinical applications in oral and aesthetic surgery.

• 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.

• Parasites, Hosts and Diseases
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• v.27 no.1
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• pp.35-40
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• 1989

It is well known that the duodenum of mice or rats infected with Fibricoln seoulensis shows atrophy of villi (shortening, blunting, widening, fusion) and hyperplasia of crypts. This study was performed to observe healing process of .these pathological changes after deworming with anthelmintic treatment. Albino rats infected each with.1,000 metacercariae of F. seeulensis were treated with single dose of 10 mg/kg praziquantel on day 15 post·infection. On day 1, 3, 5, 7, 15, 21 and 28 after the treatment, they were sacrificed and their duodenums were histopathologically studied. Control (uninfected) rats showed their normal finger-like projections of duodenal villi and well arranged crypts. In comparison, untreated (infected) contiols revealed severe mucosal changes characteristic of villous atrophy and crypt hyperplasia in their duodenum. The damaged duodenal mucosa was found to restore its normal morphology after praziquantel treatment; until day 3 post-treatment the mucosa was severely atrophied; on day 5 long and slender villi sometimes appeared among the fused and stout ones; after day 15 the villi were in their normalising process. From this experiment, it was shown that the mucosal changes in the duodenum of rats caused by F. seoulensis infection were completely reversible in 21∼28 days after anthelmintic treatment.

• Applied Microscopy
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• v.42 no.2
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• pp.67-76
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• 2012

The biomimetic approach on the cuticular spinning nozzles of the major ampullate silk glands in the golden-web spider Nephila calvata has been attempted using various visualizing techniques of light and electron microscopes to improve the design of spinning nozzle for producing synthetic nanofibers spun from electrospinning apparatus. The major ampullate spigot which has the most effective nozzle system to produce nanofibers for dragline silk with high strength and elasticity is connected via the bullet type spigot on anterior spinneret with flexible terminal segment. The excretory duct which transports the liquid silk feedstock from ampulla to spigot is divided into 3 limbs by loops back on itself to form an S-shape morphology that is bundled in connective tissue. Final diameter of the nanofibers at nozzle was dramatically reduced by gradual narrowing of duct cuticle less than 10 times comparing to its original size of funnel region. Moreover, the funnel has a characteristic cuticular organization with porous microstructure which seems to be related to water removal from feedstock of silk precursors. High magnification electron micrographs also reveal the presence of the spiral grooves on the surface of the cuticular intima near the valve which presumed to reduce friction during rapid flow of liquid silk.

• Elastomers and Composites
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• v.45 no.2
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• pp.112-121
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• 2010

In this study, styrene butadiene rubber(SBR)/organoclay nanocomposites were manufactured using the latex method with 3-aminopropyltriethoxysilane(APTES) as a modifier. The X-ray diffraction(XRD), transmission electron microscopy(TEM) images, Fourier transform infrared(FTIR) spectroscopy, swelling ratio and mechanical properties were measured in order to study the interaction between filler and rubber according to the mixing temperature in the internal mixer. In the case of SBR/APTES-MMT compounds, the dispersion of the silicates within the rubber matrix was enhanced, and thereby, the mechanical properties were improved. The characteristic bands of Si-O-C in APTES disappeared after hydrolysis reaction in the MMT-suspension solution and the peak of hydroxyl group was increased. Therefore the formation of chemical bonds between the hydroxyl group generated from APTES on the silicate surface and the ethoxy group of bis(triethoxysilylpropyl) tetrasulfide(TESPT) was possible. Consequently, the 300% modulus of SBR/APTES-MMT compounds was further improved in the case of using TESPT as a coupling agent. However, the silanization reaction between APTES and TESPT was not affected significantly according to the increase of mixing temperature in the internal mixer.

• Journal of the Mineralogical Society of Korea
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• v.21 no.4
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• pp.397-413
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• 2008

In Gaya area, the Boseong kaolin deposits exhibit locally unusual occurrences such as downward enrichment of kaoin minerals, characteristic hydrothermal alterations (illite and stilbite), and phase relations among kaolin minerals in addition to the extensive weathering of anorthositic country rocks. This indicates that the kaolin deposits seem to be genetically formed as a mixed hydrothermal and residual model. The kaolin ores can be divided into five types on the basis of differences in occurrence, mineral composition and characters. These consist of two types of high-grade ores ranging above 80% in grade and low-grade ores as low as less than 80% including feldspar residuals or the peculiar impurity phase of illite-vermiculite-stilbite. Halloysite and kaolinite are mostly coexisted in the Boseong kaolin, and these kaolin minerals exhibit diverse appearances in crystallinity and morphology. Such a diversity in mineral phase and crystallinity seems to be originated from the complexity in genesis. In addition to these diverse characters of the kaolin, its applied-mineralogical characteristics such as chemical composition, thermal properties, whiteness, viscosity, and etc. made it disadvantageous in terms of ore quality.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.321-334
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• 2017

Process surveillance within agricultural biogas plants (BGPs) was concurrently studied by high-throughput 16S rRNA gene amplicon sequencing and an optimized quantitative microscopic fingerprinting (QMF) technique. In contrast to 16S rRNA gene amplicons, digitalized microscopy is a rapid and cost-effective method that facilitates enumeration and morphological differentiation of the most significant groups of methanogens regarding their shape and characteristic autofluorescent factor 420. Moreover, the fluorescence signal mirrors cell vitality. In this study, four different BGPs were investigated. The results indicated stable process performance in the mesophilic BGPs and in the thermophilic reactor. Bacterial subcommunity characterization revealed significant differences between the four BGPs. Most remarkably, the genera Defluviitoga and Halocella dominated the thermophilic bacterial subcommunity, whereas members of another taxon, Syntrophaceticus, were found to be abundant in the mesophilic BGP. The domain Archaea was dominated by the genus Methanoculleus in all four BGPs, followed by Methanosaeta in BGP1 and BGP3. In contrast, Methanothermobacter members were highly abundant in the thermophilic BGP4. Furthermore, a high consistency between the sequencing approach and the QMF method was shown, especially for the thermophilic BGP. The differences elucidated that using this biphasic approach for mesophilic BGPs provided novel insights regarding disaggregated single cells of Methanosarcina and Methanosaeta species. Both dominated the archaeal subcommunity and replaced coccoid Methanoculleus members belonging to the same group of Methanomicrobiales that have been frequently observed in similar BGPs. This work demonstrates that combining QMF and 16S rRNA gene amplicon sequencing is a complementary strategy to describe archaeal community structures within biogas processes.

• Journal of Korean Society of Forest Science
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• v.89 no.2
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• pp.173-184
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• 2000

The aim of this study was to characterize the forest vegetation and site of Tongdaesan(Odaesan National Park) for ecological forest management. The deciduous forests of Tongdaesan are the result of cool, temperate climate. Direction and slope morphology contribute to differences in species composition and vegetaion structure. Based on the BRAUN-BLANQUET-approach, 242 releves were recorded and subsequently classified. The vegetation could be divided into two forest community groups, seven forest communities, and several groups. South exposed, dry slopes were covered with forests of the Quercus mongolica-Acer pseudo-sieboldianum community group. Differential species included grasses and sedges, e.g., Calamagrostis langsdorfii, Carex humilis and C. lanceolata. Quercus mongolica-Acer pseudo-sieboldianum community group could be subdivided into Rhododendron mucronulatum var. ciliatum community, Lespedeza${\times}$tomentella community, Carex humilis-Maackia amurensis community, Quercus mongolica-Acer pseudosieboldianum typical community and Pimpinella brachycarpa community. Carex humilis-Maackia amurensis community was divided into Galium kinuta subcommunity and typical subcommunity. Pimpinella brachycarpa community was divided into Vicia venosa var. cuspidata subcommunity and typical subcommunity. On north exposed, more humid and moist sites, forests of the Dryopteris crassirhizoma-Cornus controversa community group were found. This group was subdivided into Acer tschonoskii var. rubripes-Acer tegmentosum community and Deutzia glabrata-Ulmus laciniata community. Deutzia glabrata-Ulmus laciniata community was divided into Acer tegmentosum subcommunity, Saxifraga punctata subcommunity and typical subcommunity.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.44-50
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• 2002

Apert syndrome is a kind of congenital-acrocephalosyndactyly syndrome which was first reported by Apert in 1906 and characterized by its acrocephaly and syndactyly. Clinical characteristic features are cone-shaped skull morphology due to early fusion of coronal suture, fusion of fingers of hands and toes of feet. It is an autosomal dominant-heritable syndrome. Due to hypo-development of midface region, Apert syndrome patients have a tendency to have ocular proptosis, hypertelorism, maxillary deficiency. High palate and soft palate cleft are common findings in these patients. In general, mandibular growth pattern is normal, but relative maxillary deficiency exaggerates mandibular forward position, so relative mandibular prognathism is inevitable. Narrow maxillary and mandibular dental arch worsen teeth alignment and crowding. Skeletal malocclusion and open bite are also common. This is a case report of a Korean 3 year 1 month male Apert syndrome child referred by department of plastic surgeon for the possibility of orthodontic treatment. General features of Apert syndrome, patient's medical history, radiographic evaluation, clinical examination, orthodontic and surgical treatment planning are discussed in this report.