• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.349-353
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• 1994

An isolate 90-GT-302, identified as Kitasatosporia kimorexae, was found to produce antibiotics that induce mycelial swelling in Magnaporthe grisea, and Fusarium solani. The strain produced at least 5 antibiotics. Among them, the main active compound designated as kimorexin A was isolated and its physico-chemical properties and biological activities were examined, and as a result was found to be of the thiopeptide antibiotic. A comparison between the properties of kimorexin A and those of the known thiopeptide antibiotics led us to conclude that kimorexin A was a new thiopeptide polythiazolyl antibiotic. Kimorexin A showed a narrow antimicrobial spectrum against very limited genus of phytopathogenic fungi. It prevented host plants from infections of Rhizoctonia solani and absolute parasitic fungi, such as Sphaerotheca fuliginea and Puccinia recondita, almost completely at the treatment concentration of approximately 20 ppm.

• Structural Engineering and Mechanics
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• v.43 no.2
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• pp.211-223
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• 2012

This paper deals with large deformation post-buckling of a linear-elastic and hygrothermal beam with axially nonmovable pinned-pinned ends and subjected to a significant increase in swelling by an alternative method. Analytical approximate solutions for the geometrically nonlinear problem are presented. The solution for the limiting case of a string is also obtained. By coupling of the well-known Maclaurin series expansion and orthogonal Chebyshev polynomials, the governing differential equation with sinusoidal nonlinearity can be reduced to form a cubic-nonlinear equation, and supplementary condition with cosinoidal nonlinearity can also be simplified to be a polynomial integral equation. Analytical approximations to the resulting boundary condition problem are established by combining the Newton's method with the method of harmonic balance. Two approximate formulae for load along axis, potential strain for free hygrothermal expansion and periodic solution are established for small as well as large angle of rotation at the end of the beam. Illustrative examples are selected and compared to "reference" solution obtained by the shooting method to substantiate the accuracy and correctness of the approximate analytical approach.

• Journal of Veterinary Clinics
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• v.19 no.1
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• pp.103-106
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• 2002

Specific diagnosis of orthopedic disease can be diffcult in canine practice. Failure to detect the clinical signs of a disorder during physical examination of dogs with acute or chronic lameness is the most common reason for failure to make specific diagnosis. A 6-month-old, female doberman with history of swelling and non-weight-bearing lameness in the left forelimb was referred to Beterinary Teaching Hospital of Chungbuk National University. Physical examination, plain radiography, and conventional three-phase radionuclide bone scan were performed in the patient. Based on the physical exam and radiography, this case was diagnosed as elbow strain and subluxation. Conventional three-phase bone scan detected soft tissue inflammation and osteochondral lesions of elbow joint, and revealed good agreement with clinical findings. Therefore, conventional three-phase bone scan was able to provide the precise information about inflammation of soft tissue and osteochondral lesions of joint.

• Korean Journal of Veterinary Research
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• v.30 no.1
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• pp.93-102
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• 1990

Thirty-day-old piglets were intranasally or subcutaneously inoculated with 2ml of Aujeszky's disease virus, NYJ-1 strain, at the titer of $10^{6.75}$ $TCID_{50}/0.1ml$, that was isolated from the diseased piglets in Korea, and histopathological studies were performed to elucidate the pathognomonic characters of the isolate. Results obtained through the experiments were as follows: 1. Major clinical signs on the 2nd and 3rd days post inoculation (p.i.) were fever, anorexia and dyspnea. On the 6th and 7th days p.i., nervous signs, severe dyspnea and salivation were observed in the group of intranasal inoculation, and one out of 3 piglets in this group died on the 7th day p.i.. General signs were more severe in the group of intranasal inoculation than the group of subcntaneous injection. Between the 8th and l0th days p.i., the signs subsided and the piglets were completely recovered from the illness. 2. Hematologically, most of the inoculated pigs showed a mild lymphocytopenia on the 5th and 6th days p.i.. 3. By necropsy, swelling and hemorrhagic lesions were observed in tonsil, central nervous system and lung. No specific changes were grossly found in other parenchymatous organs. 4. In histopathological study, degeneration and necrosis of nervous cells, non-suppurative meningoencephalitis, diffuse or focal gliosis, perivascular cutting and degeneration of ganglion cells were observed in central nervous system, and swelling and hemorrhagic changes were shown in the tissues of liver, lung and lymph nodes. 5. By indirect immunofluorescence antibody assay using ADV-monoclonal antibody, specific ADV antigens were detected in the tissues of tonsil, brain and spleen of the succumbed piglet. However, in the experimentally slaughtered piglets, the specific reactions were noted only in the tonsils.

• Geomechanics and Engineering
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• v.12 no.5
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• pp.831-847
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• 2017

Conventional geotechnical engineering soil binders such as ordinary cement or lime have environmental issues in terms of sustainable development. Thus, environmentally friendly materials have attracted considerable interest in modern geotechnical engineering. Microbial biopolymers are being actively developed in order to improve geotechnical engineering properties such as aggregate stability, strength, and hydraulic conductivity of various soil types. This study evaluates the geotechnical engineering shear behavior of sand treated with xanthan gum biopolymer through laboratory direct shear testing. Xanthan gum-sand mixtures with various xanthan gum content (percent to the mass of sand) and gel phases (initial, dried, and re-submerged) were considered. Xanthan gum content of 1.0% sufficiently improves the inter-particle cohesion of cohesionless sands 3.8 times and more (up to 14 times for dried state) than in the untreated (natural) condition, regardless of the xanthan gum gel condition. In general, the strength of xanthan gum-treated sand shows dependency with the rheology and phase of xanthan gum gels in inter-granular pores, which decreases in order as dried (biofilm state), initial (uniform hydrogel), and re-submerged (swollen hydrogel after drying) states. As xanthan gum hydrogels are pseudo-plastic, both inter-particle friction angle and cohesion of xanthan gum-treated sand decrease with water adsorbed swelling at large strain levels. However, for 2% xanthan gum-treated sands, the re-submerged state shows a higher strength than the initial state due to the gradual and non-uniform swelling behavior of highly concentrated biofilms.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.7-20
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• 1987

The author studied the acute reaction of cobalt-60 irradiation to buccal mucosa in rats and difference of the effects of single versus fractionated exposure. 195 Sprague Dowley strain rats, weighing about 120gm, were used in this experiment. 3 rats served as controls and the remaining 192 rats were divided into six groups of 32 rats each. Experimental group Ⅰ, Ⅱ, Ⅲ were received a single dose of 15Gy, 16.5Gy, 18Gy and group Ⅳ, Ⅴ, Ⅵ were received two equal sized fractionated dose of 9Gy, 9.75Gy, 10.5Gy at 4 hour intervals, respectively. The experimental groups were irradiated with cobalt-60 teletherapy unit, Picker model 4M 60 (Field size, 12x5 cm, SSD, 50㎝, Dose rate, 222cGy/min, Depth, 1㎝). The animals were sacrificed at 1, 2, 3, 6, 12 hours, 1, 3, 7 days after irradiation and the changes of the irradiated buccal mucosa were observed by electron and light microscopy. The results were as follows: 1. A single exposure was more damaging than fractionated exposure, and as the radiation dose increased, the changes of cell organelles became faster, but the healing of radiation-induced damage in fractionated exposure was faster than in single exposure. 2. The radiation-induced changes of the basal cells were the most prominent in 18Gy-single exposure group, and the least in 18Gy-fractionated exposure group. 3. Electron-microscopically, there appeared nuclear changes, swelling of mitochondria and rough endoplasmic reticulum, decrease of free ribosome, presence of vesicles, widening of intercellular space, and loss of basal lamina. The early remarkable changes were partly loss of nuclear membrane and swelling of mitochondria. 4. Light-microscopically, derangement and pyknosis of basal cells, hydropic changes of spinous cells, enlargement of granular cells, indistinctness of basement membrane, and proliferation of epithelium were observed.

• Korean Journal of Veterinary Research
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• v.53 no.1
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• pp.11-17
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• 2013

In this study, to understand the pathogenesis of new rabbit hemorrhagic disease virus (RHDVa) serotype, we carried out to administrate RHDVa to rabbits, and to examine sequential electron microscopic changes and relationship between pathogenesis and apoptosis. TUNEL-positive cells began to be observed from 24 hours after inoculation (HAI) and the number of positive cells was slightly increased with the course of time. Whereas marked increase of positive cells was seen in the liver from the rabbits died acutely. Typical viral particles with cup-like projections and a diameter of 30~40 nm were detected in homogenized liver samples and tissues at 36 and 48, and 48 HAI, respectively. Ultrastructurally, glycogen deposition was observed from the first stage of hepatocellular degeneration by RHDVa infection and then, swelling and disruption of cristae of mitochondria by viral particles, swelling of smooth endoplasmic reticulum, vacuoles and vesicles were detected. Condensation, margination and fragmentation of chromatin were observed in degenerative hepatocytes at 36 and 48 HAI, indicating apoptotic bodies. These data offer that hepatocytic apoptosis by RHDV infection could be closely related with mitochondrial impairment in the hepatocytes.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.535-543
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• 2019

Building on/with expansive soils with no treatment brings complications. Compacted expansive soils specifically fall short in satisfying the minimum requirements for transport embankment infrastructures, requiring the adoption of hauled virgin mineral aggregates or a sustainable alternative. Use of hauled aggregates comes at a high carbon and economical cost. On average, every 9m high embankment built with quarried/hauled soils cost $12600MJ.m^{-2}$ Embodied Energy (EE). A prospect of using mixed cutting-arising expansive soils with industrial/domestic wastes can reduce the carbon cost and ease the pressure on landfills. The widespread use of recycled materials has been extensively limited due to concerns over their long-term performance, generally low shear strength and stiffness. In this contribution, hydromechanical properties of a waste tyre sand-sized rubber (a mixture of polybutadiene, polyisoprene, elastomers, and styrene-butadiene) and expansive silt is studied, allowing the short- and long-term behaviour of optimum compacted composites to be better established. The inclusion of tyre shred substantially decreased the swelling potential/pressure and modestly lowered the compression index. Silt-Tyre powder replacement lowered the bulk density, allowing construction of lighter reinforced earth structures. The shear strength and stiffness decreased on addition of tyre powder, yet the contribution of matric suction to the shear strength remained constant for tyre shred contents up to 20%. Reinforced soils adopted a ductile post-peak plastic behaviour with enhanced failure strain, offering the opportunity to build more flexible subgrades as recommended for expansive soils. Residual water content and tyre shred content are directly correlated; tyre-reinforced silt showed a greater capacity of water storage (than natural silts) and hence a sustainable solution to waterlogging and surficial flooding particularly in urban settings. Crushed fine tyre shred mixed with expansive silts/sands at 15 to 20 wt% appear to offer the maximum reduction in swelling-shrinking properties at minimum cracking, strength loss and enhanced compressibility expenses.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.20 no.1
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• pp.39-48
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• 2024

Research reactors are operated under ambient temperature and atmospheric pressure, which is much less severe conditions compared to those in typical nuclear power plants. Due to the high temperature, heat resistant materials such as austenite stainless steel should be used for the reactors in typical nuclear power plants. Whereas, as the effect of temperature is low for research reactors, materials with high resistance to neutron irradiation, such as zircaloy and beryllium, are used. Therefore, these conditions should be considered when performing integrity assessment for research reactors. In this study, a computational technique through finite element (FE) analysis was developed considering the operating conditions and materials of research reactor when conducting integrity assessment. Neutron irradiation analysis techniques using thermal expansion analysis were proposed to consider neutron irradiation growth and swelling in zirconium alloys and beryllium. A user subroutine program that can calculate the strain rate induced by neutron irradiation creep was developed for use in the commercial analysis program Abaqus. To validate the proposed technique and the user subroutine, FE analysis results were compared with hand-calculation results, and showed good agreement. Consequently, developed technique and user subroutine are suitable for evaluating structural integrity of research reactors.

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3884-3897
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• 2024

This study investigates the creep behavior of bentonite-sand mixtures as potential buffer materials for low-level radioactive waste (LLW) repositories, with a specific case study in Taiwan. To assess the long-term hydro-mechanical properties, constant-volume swelling pressure, hydraulic conductivity, strain-controlled shear, and stress-controlled shear tests were conducted on MX80 and KV1 bentonite-sand mixtures. The experimental results indicate that MX80-sand 70/30 mixtures are prioritized as the buffer materials with 2.10 MPa swelling pressure and 1 × 10^-13 m/s hydraulic conductivity. However, the shear strength of mixtures was reduced by almost 50 % when fully saturated. Furthermore, this study proposed a novel stress-controlled direct shear apparatus to retrieve the creep model parameters. The numerical method based on the creep model efficiently supports and simulates the saturation process and creep displacement. The finite element method (FEM) result predicts that the buffer of both bentonite-sand mixtures will achieve an average degree of saturation of 95 % at the end of three decades and full saturation in 100 years. The simulated creep displacement results at key nodes suggest that both top and bottom parts in the buffer, assembled from MX80-sand 70/30 mixtures or KV1-sand 70/30 mixtures, will have almost equivalent values of 4 mm in the horizontal and 2 mm in the vertical directions eventually.