• Animal cells and systems
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• 제1권2호
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• pp.329-335
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• 1997

The final pattern of the skeletal muscle of a vertebrate depends on the position-specific behavior of the muscle precursor cells during early developmental process and the abdominal muscle is made of cells which migrate a relatively long distance from their original tissue, myotome of dorsal mesoderm. We report the spatia-temporal migration pattern of abdominal muscle in Xenopus laevis by in situ hybridization and immunohistological studies. Shortly after hatching tadpole stage (stage 31/32), a group of myotomal cells detaches from the lower tip of the second somite and migrates ventrally to the lower position of abdomen. At stage 34/35, a second cell group migrates away from the third somite. Total 7 myotomal cell groups migrate ventrally one by one from the second to eighth myotome along their own pathways through the cell free space located between epidermis and subepidermal layer of the abdomen. During migration, the sizes of the cell groups (abdominal muscle anlagens) are increased to several tens fold. Around stage 40 all the abdominal muscle anlagens reaches their final positions and are interconnected side by side rostrocaudally. They are also connected to other types of muscles, forming a large multisegmented abdominal muscle. Heat shock study suggests that the disruption of segmentation of somites does not block the detachment of abdominal muscle anlagen, though the treatment gave stage- and dosagedependent effects on the migration speed.

• Journal of Welding and Joining
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• 제26권1호
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• pp.69-75
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• 2008

Spot welding which use the main process for side block production of stainless steel railway vehicle is legged behind in laser welding about a quality and productivity. Although the laser welding has many potential advantages such as low heat input and aspect ratio of weld bead, its application to a new structural component still is required many engineering data including mechanical properties such as tensile, fatigue strength, etc on. Therefore, experimental analysis was carried out to understand the fatigue phenomena of different thickness stainless steel overlap joining panels by Nd:YAG laser welding. The fatigue life curves were obtained through fatigue tests with the various levels of applied load. The fatigue life is related with the parameters such as gap size and penetration depth through experiment. As the results, tensile strength and fatigue life were proportional in heat input level and gap was identified the major factor for fatigue life. Also we could know that deferent a-ferrite content at HAZ depend on welding heat input was important factor to determine a formation of initial crack and total fatigue life cycle.

• 한국수소및신에너지학회논문집
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• 제26권6호
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• pp.532-540
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• 2015

Electrochemical alane ($AlH_3$) production process can be provided as a synthesis route which close a reversible cycle. In this study, growth inhibition of dendrite as key issues in this process was investigated. Main cause of dendrite growth was because Al fine powder separated in consumption process of Al electrode was moved to Pd electrode. In an effort to avoid this, use of glass block with uniform holes was the most effective to inhibit the amount of dendrite to that of $AlH_3$. Furthermore, effects of Al electrode (anode) type and electrolyte concentration were investigated and the optimal condition for inhibiting dendrite formation was proposed.

• 한국가축번식학회지
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• 제14권1호
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• pp.50-56
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• 1990

Bovine oocytes obtained from follicles(2~5mm) of ovaries after slaughter were cultured in TCM 199 medium with 10~20% heat-inactivated estrus cow serum(ECS) for 25~27 hr, at 39$^{\circ}C$ under 5% CO2 in air. At the end of culture period, some oocytes were stained with 1% acetoorcein and examined for the evidence of oocyte maturation. The remainder were used to assess the potential of in vitro fertilization(IVF) with frozen-thawed spermatozoa and subsequent development in media with or without bovine oviduct epithelial cell (BOEC) co-culture. The results obtained were summarized as follows ; 1. The maturation rate of oocyte in vitro in TCM 199 medium with 15% ECS group(76.3) was superior to 10% ECS group(68.3%) and 20% ECS group(64.5%). 2. The IVF rates of oocytes matured in vitro, and formation rate of male and female pronuclei were 63.6%(77/121) and 93.5%(72/77), respectively. The incidence of polyspermy was very low(2.4%). 3. Of 73 oocytes fertilized in vitro and cultured in TCM 199 medium with 10% fetal calf serum for 7 days, 41(56.3%) were cleaved over 2-cell and only 1(2.4%) was developed beyond the 16-cell stage. 4. Of 76 oocytes co-cultured with BOEC, 58(76.3%) were cleavaged and 23(39.7%) were developed to morula and blastocyst stage. The results of this study indicate that co-culture with BOEC deserved a positive effect on the IVF oocyte development through the 16-cell block.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.70-73
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• 2001

Isopentenyl diphosphate (IPP) is the common, five-carbon building block in the biosynthesis of all isoprenoids. IPP in Escherichia coli is synthesized through the non-mevalonate pathway. The first reaction of IPP biosynthesis in E. coli is the formation of 1-deoxy-D-xylulose-5-phosphate(DXP), catalyzed by DXP synthase and encoded by dxs. The second reaction in the pathway is the reduction of DXP to 2-C-methyl-D-erythritol-4-phosphate, catalyzed by DXP reductoismerase and encoded by dxr. To determine if one of more of the reactions in the non-mevalonate pathway controlled flux to IPP, dxs and dxr were placed on several expression vectors under the control of three different promoters and transformed into three E. coli strains ($DH5{\alpha}$, XL1-Blue, and JM101) that had been engineered to produce lycopene, a kind of isoprenoids. Lycopene production was improved significantly in strains transformed with the dex expression vectors. At arabinose concentrations between 0 and 1.33 mM, cells expressiong both dxs and from $P_{BAD}$ on a midium-copy plasmid produced 1.4 -2.0 times more lycopene than cells expressing dxs only. However, at higher arabinose concentrations lycopene production in cell expressing both dxs and dxr was lower than in cells expression dxs only. A comparison of the three E. coli strains trasfomed with the arabinose-inducible dxs on a medium-copy plasmid revealed that lycopene production was highest in XL1-Blue.

• 자원환경지질
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• 제21권4호
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• pp.335-348
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• 1988

The author aimed to describe the volcano-stratigraphy and petrology of the volcanic mass in the Koheung peninsula, South Cheolla province. The volcanic mass is composed of the volcanics and intrusives of late Cretaceous which extruded the Pre-cambrian metamorphic(Jirisan gneiss complex) and the early Cretaceous sedimentary(Duwon Formation) basement. The volcanic pile consists of, in ascending order, Bibongsan andesite, Koheung tuff and breccia, and Palyeongsan welded tuff, and are intruded by ring intrusives( intrusive breccia, andesite porphyry, intrusive rhyolite and fine-grained quartz-diorite) and central pluton(diorite, quartz monzodiorite, biotite granite and micrographic granite). Bibongsan andesite mainly consists of andesite tuff and lava. Koheung tuff consists of alternation of fine tuff, coarse tuff and lapilli tuff, and Palyeongsan welded tuff which overlies Koheung tuff, comprises K-feldspar and quartz phenocrysts, elongated brown fiamme, lithic fragments in matrix of devitrified brown glass shards, and mainly consists of rhyodacite to rhyolite vitric ash-flow tuff. The results of petrochemical studies of the igneous rocks suggest that the rocks were a serial differentiational products of fractional crystallization of calc-alkaline magma series. This study reveals that the volcanic mass in this area is inferred to the remnant of the resurgent cauldron, measuring 30 by 25 km in diameter. The cauldron block was lowered at least 1,000 m by ring fault displacement.

• Journal of the Korean Wood Science and Technology
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• 제21권1호
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• pp.39-50
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• 1993

The purpose of this study was to describe the micromorphological changes in Korean red pine (Pinus densiflora S. et Z.) wood decayed by a major brown-rot fungus, Lentinus lepideus, using scanning electron microscope and transmission electron microscope. At the end of the 12-week exposure to the fungus in soil block procedure(ASTM 1971), test blocks sustained 5.02% weight loss. The formation of bore hole by hyphae and penetration of hyphae through bordered pit were not observed. Instead, fungal hyphae appeared to penetrate axially tracheid luminar from the the ray cells via cross field pits. Hyphae were mainly found in lignin rich cell corner regions of tracheids, and also extensive degradation of tracheid wall occurred in this region. Extensive degradation of $S_2$ layer occurred without noticeable alteration of the $S_3$ layer, but warty layer and compound middle lamella remained relatively intact. Localized erosion, the characteristic of white rot, was observed in some cell wall and wall components including lignin were found to be decomposed.

• Journal of Chest Surgery
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• 제15권1호
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• pp.118-123
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• 1982

Fourteen cases of pericardia I tumor were clinically experienced from June 1966 to July 1981, for 15 years in St. Mary's Hospital, Department of Thoracic and Cardiovascular Surgery, Catholic Medical College. There were three primary tumors of the pericardium, liposarcoma, teratoma and malignant mesothelioma, and 11 metastatic pericardial tumors. In metastatic pericardial tumors, eight were originated from the lung, one was breast, and the other two cases were unknown origin. There were 6 adenocarcinoma, one small cell carcionoma ~nd one alveolar cell carcinoma in 8 cases from the lung, and 5 male and 3 female patients were composed the metastatic pericardial cancer from the lung. In clinical symptoms were dyspnea in all cases, and 9 cases had the generalized edema and enlarged liver size. Six patients had been operated, three of the primary pericardial tumor and three of metastatic pericardial tumor. Two of the primary tumors were cured satisfactorily by the mass removal, but one died due to cardiac arrest at postoperative one day. In metastatic tumors, operation were performed as two pericardial window formation and one left lower lobectomy with pericardial fenestration, but one was died in second operative day. Other nine metastatic tumors were diagnosed by needle biopsy in one case and by cell block of effusion in eight cases.

• Journal of Microbiology and Biotechnology
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• 제19권10호
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• pp.1230-1237
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• 2009

The selective plugging strategy of Microbial Enhanced Oil Recovery (MEOR) involves the use of microbes that grow and produce exopolymeric substances, which block the high permeability zones of an oil reservoir, thus allowing the water to flow through the low permeability zones leading to increase in oil recovery. Bacillus licheniformis TT33, a hot water spring isolate, is facultatively anaerobic, halotolerant, and thermotolerant. It produces EPS as well as biosurfactant and has a biofilm-forming ability. The viscosity of its cell-free supernatant is $120\;mPa{\cdot}s$ at $28^{\circ}C$. Its purified EPS contained 26% carbohydrate and 3% protein. Its biosurfactant reduced the surface tension of water from 72 to 34 mN/m. This strain gave $27.7{\pm}3.5%$ oil recovery in a sand pack column. Environmental scanning electron microscopy analysis showed bacterial growth and biofilm formation in the sand pack. Biochemical tests and Amplified Ribosomal DNA Restriction Analysis confirmed that the oil recovery obtained in the sand pack column was due to Bacillus licheniformis TT33.

• 폴리머
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• 제37권3호
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• pp.294-301
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• 2013

Polymersomes made of biodegradable triblock copolymers based on poly(fumaric acid-co-sebacoyl chloride)/PEG (PEG-co-P(FA/SC)-co-PEG) were prepared and studied in aqueous solutions. TEM confirmed the formation of vesicles in aqueous media. Aggregation behavior of the copolymers was studied by fluorescence spectroscopy of 8-anilino-1-naphthalenesulfonic acid, and the critical aggregation concentration (c.a.c.) of the copolymer was found to be ${\sim}26.2{\mu}M$ indicating desirable stability of the vesicles. Dynamic light scattering revealed that the size of the vesicles was distributed within the range of 170-270 nm. Turbidity measurements confirmed the relative short-term stability of the polymersomes. Carboxyfluorescein, a hydrophilic compound, was simply encapsulated in the vesicles during polymersome preparation. The release of encapsulant from the polymersomes at 25 and $37^{\circ}C$ lasted about 3 weeks, and the rate of release followed a first-order kinetics. The release is speculated to be primarily carried out through diffusion. These results confirm that these polymersomes are promising as controlled-release carriers of various drugs.