• Korean Journal of Veterinary Service
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• v.32 no.1
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• pp.19-25
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• 2009

Porcine reproductive and respiratory syndrome (PRRS) virus is the etiological agent of diseases characterized by reproductive losses in sows and respiratory disorders in piglets. The PRRS virus is a small enveloped virus containing a positive-sense, single-stranded RNA genome. In the present study, ORF6 gene of Korean PRRS virus isolate, CNV, was cloned and expressed in baculovirus expression system. The ORF6 gene and expressed protein in the recombinant virus were confirmed by PCR/indirect fluorescence antibody (IFA) test and Western blotting, respectively. The recombinant protein with a molecular weight of approximately 24KDa was confirmed by Western blotting using His6 and PRRS virus-specific antiserum. Expressed ORF6 protein was applied for IFA to detect antibody against PRRS virus using field porcine sera. However, the sensitivity and specificity of developed IFA using expressed ORF6 protein were considerably low compared to those of commercial ELISA kit. This results suggest that IFA using expressed ORF6 protein could not be used as a diagnostic test for PRRS virus infection without further improvements.

• Journal of fish pathology
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• v.31 no.1
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• pp.1-8
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• 2018

Causative agent of infectious hematopoietic necrosis (IHN) belonging to genus Novirhabdovirus (Rhabdoviridae). Economic losses caused by IHNV are serious in mainly Oncorhynchus spp. including rainbow trout O. mykiss and Atrantic salmon Salmo salar. IHNV was initially found by endemic presence in U.S. West Coast for sockeye salmon fry O. nerka and chinook salmon fry O. tshawytscha in the 1950s, and it has spread to Japan, Korea and Taiwan in the 1970s, and also to Italy and France in the 1990s. Currently, IHNV is detectable in many parts of the world, including Russia and South America. Mortality due to IHNV infection in fish with ${\leq}0.5g$ of body weight reaches 60% to 100%, while the mortality reduces by fish growing. In recent years, onset of IHNV infection has increased also in fish with large sizes. Here, we introduce molecular epidemiology and virulence changes of IHNV in East Asia, furthermore, we discuss on future prospects in IHNV researches.

• Plant Resources
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• v.2 no.1
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• pp.42-48
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• 1999

This study was undertaken to examine the feasibility of black locust (Robinia pseudoacacia) as substrates for several edible mushrooms. For the cultivation of several edible and/or medicinal fungi on black locust, optimum bulk densities, synthetic or semisynthetic additives, natural additives and pretreatment methods were investigated. Fruit body yields of the fungi on various sawdust media composed of different wood species were also analyzed for testing the capability of black locust as a substrate for mushroom production. Mycelial growths decreased proportional when the bulk density increased. The most suitable carbon and nitrogen sources as additives to promote the mycelial growth were sucrose (2%, w/w) and ammonium phosphate (0.2%, w/w) respectively. When corn-powder and beer-waste as natural additives were added to sawdust of black locust showed the significant growth of mycelia. And the optimum mixing ratio was 10:2:1 (sawdust: corn-powder: beer-waste, w/w). Black locust after cold water treatment showed the outstanding mycelial growths. Any significant changes of pH, moisture content (%) and dry-weight losses (%) could not be found among culture substrates (sawdust of black locust, oak and poplar wood) examined before and after harvesting of fruit bodies. Yield of fruit bodies on black locust culture media were comparable with those culture media composed with oak and poplar wood. The present work indicated strongly the potentiality of black locust as raw materials for edible and medicinal mushrooms.

• International Journal of Aerospace System Engineering
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• v.8 no.1
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• pp.1-13
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• 2021

Contra-rotating fan is comprised of two rotors which are rotating in the opposite direction. The fan stages are named rotor-1 and rotor-2. Benefits from the use of contra rotation are in terms of better efficiency and improved thrust to weight ratio. Failure of contra-rotating fan stage blade in-service results in safety risks, repair costs, and revenue losses. This paper focuses on the vibration analysis and one way fluid-structure interaction of high aspect ratio, low speed contrarotating fan rotors. Modal analysis and modal pre-stress analysis of contra-rotating fan rotors were carried out to calculate the natural frequencies, One way fluid-structure interaction (FSI) was carried out where the computational analysis of the blades was performed using ANSYS CFX. The boundary conditions for CFD analysis were considered from the actual experimental velocity flow field at the inlet and pressure outlet. Based on the results obtained from the CFD analysis, the structural analysis such as deformation and Von-Misses stresses was carried out by using the finite element method (FEM) with ANSYS. The results provide necessary guidelines for the safe running of the contra-rotating fan. The analysis also will be helpful to understand the change of flow behavior due to a rotor deformation.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.471-480
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• 2019

The constructions of engineering structures such as airports, highways and railway on clayey soils may create many problems. The economic losses and damages caused by these soils have led researchers to do many studies using different chemical additives for the stabilization of them. Lime is a popular additive used to stabilize the clayey soils. When the base course is stabilized by mixing with an additive, inevitable delays may occur during compaction due to reasons like insufficient workers, breakdown of compaction equipment, etc. The main purpose of this study is to research the effect of compaction delay time (7 days) on the strength, compaction, and dynamic properties of a clay soil stabilized with lime content of 0, 3, 6, 9, 12 and 15% by dry weight of soil. Compaction characteristics of these mixes were determined immediately after mixing, and after 7 days from the end of mixing process. Within this context, unconfined compressive strength (UCS) under the various curing periods (uncured, 7 and 28 days) and dynamic triaxial tests were performed on the compacted specimens. The results of UCS and dynamic triaxial tests showed that delayed compaction on the strength of the lime-stabilized clay soil were significantly effective. Especially with the lime content of 9%, the increase in the shear modulus (G) and UCS of 28 days curing were more prominent after 7 days mellowing period. Because of the complex forms of hysteresis loops caused by the lime additive, the damping ratio (D) values differed from the trends presented in the literature and showed a scattered relationship.

• Journal of Applied Biological Chemistry
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• v.62 no.3
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• pp.293-297
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• 2019

Leaf rust is the most widespread and destructive fungal disease, and outbreaks have always caused considerable losses in wheat yields. Thus, worldwide increases in wheat production depend on the development of leaf rust-resistant wheat varieties. In this study, we evaluated the resistance of forty Korean wheat cultivars to leaf rust at the seedling stage. Only two Korean wheats, Ol and Jonong, were resistant to leaf rust, whereas the remaining thirty-eight Korean wheats were susceptible to leaf rust. The Ol and Jonong varieties presented larger dry seed weights and higher antioxidant activity in response to leaf rust than the susceptible wheat varieties. No differences in ${\beta}$-1,3-glucanase activity or chlorophyll content between resistant and susceptible wheat varieties were observed. Overall, these results are important for the development of wheat varieties that are highly resistant to leaf rust and to understand the underlying mechanisms that confer leaf rust resistance.

• Korean Journal of Metals and Materials
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• v.49 no.7
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• pp.557-564
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• 2011

This paper reports the relationship between the surface roughness and thermal emissivity of graphite (IG-11) in nuclear reactors. The roughness was controlled by changing the oxidization time, resulting in 0, 6, and 11% losses of mass. The levels of roughness were 0.40, 0.72 and 1.09${\mu}m$ for the weight loss of 0, 6 and 11%, respectively. The binders and graphite fillers were found to have sequentially oxidized with a higher thermal emission for the highly oxidized sample, but with a lower emission when measured at a higher temperature. Our study suggests a method for predicting the thermal emission rate of graphite in a nuclear reactor based on roughness measurement.

• Journal of Aerospace System Engineering
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• v.15 no.1
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• pp.32-39
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• 2021

Electric propulsion aircraft are being actively researched in the aviation field in recent years to solve environmental and noise problems caused by existing gas turbine engine. In particular, research on a thrust motor as a core component of an electric power propulsion system and an inverter for driving it is actively being conducted. In this paper, a motor with high specific power is selected to determine characteristics of aircraft that are sensitive to weight and volume. Power loss of the inverter is then simulated. In the simulation, the selected motor and power device were modeled using PSIM, a power electronics analysis tool. Inverter power loss according to switching frequency was then analyzed.

• Journal of Animal Science and Technology
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• v.64 no.4
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• pp.640-653
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• 2022

Deoxynivalenol (DON) is the most common mycotoxin contaminant of cereal-based food and animal feed. The toxicity of DON is very low compared to that of other toxins; however, the most prominent signs of DON exposure include inappetence and body weight loss, which causes considerable economic losses in the livestock industry. This review summarizes critical studies on biological DON mycotoxin mitigation strategies and the respective in vitro and in vivo intestinal effects. Focus areas include growth performance, gut health in terms of intestinal histomorphology, epithelial barrier functions, the intestinal immune system and microflora, and short-chain fatty acid production in the intestines. In addition, DON detoxification and modulation of these parameters, through biological supplements, are discussed. Biological detoxification of DON using microorganisms can attenuate DON toxicity by modulating gut microbiota and improving gut health with or without influencing the growth performance of pigs. However, the use of microorganisms as feed additives to livestock for mycotoxins detoxification needs more research before commercial use.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.12
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• pp.4326-4344
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• 2021

The SinGAN is one of generative adversarial networks that can be trained on a single nature image. It has poor ability to learn more global features from nature image, and losses much local detail information when it generates arbitrary size image sample. To solve the problem, a non-linear function is firstly proposed to control downsampling ratio that is ratio between the size of current image and the size of next downsampled image, to increase the ratio with increase of the number of downsampling. This makes the low-resolution images obtained by downsampling have higher proportion in all downsampled images. The low-resolution images usually contain much global information. Therefore, it can help the model to learn more global feature information from downsampled images. Secondly, the attention mechanism is introduced to the generative network to increase the weight of effective image information. This can make the network learn more local details. Besides, in order to make the output image more natural, the TVLoss function is introduced to the loss function of SinGAN, to reduce the difference between adjacent pixels and smear phenomenon for the output image. A large number of experimental results show that our proposed model has better performance than other methods in generating random samples with fixed size and arbitrary size, image harmonization and editing.