• Journal of radiological science and technology
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• v.40 no.3
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• pp.433-441
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• 2017

The 3D printing selective laser sintering (SLS) and stereo lithography apparatus (SLA) method used for bone model production has good precision and resolution, but the printers are expensive and need professional knowledge for operation. The program that converts computed tomography digital imaging and communications in medicine (DICOM) file into STL (stereolithography) file is also expensive so requesting 3D printing companies takes a lot of time and cost, which is why they are not generally utilized in surgery. To produce bone models of fractured patients, the use of 3D imaging conversion program and 3D printing system should be convenient, and the cost of device and operation should be low. Besides, they should be able to produce big size bone models for application to surgery. Therefore, by using an fused deposition modeling (FDM) method 3D printer that uses thermoplastic materials such as DICOM Viewer OsiriX and plastic wires, this study developed 3D printing system for Fracture surgery Patients customized bone model production for many clinics to use for surgery of fracture patients by universalizing with no limit in printing sizes and low maintenance and production cost. It is expected to be widely applied to the overall areas of orthopedics' education, research and clinic. It is also expected to be conveniently used in not only university hospitals but also regular general hospitals.

• Journal of Animal Science and Technology
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• v.58 no.5
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• pp.18.1-18.10
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• 2016

Muscle, studied mostly with respect to meat production, represents one of the largest protein reservoirs of the body. As gene expression profiling holds credibility to deal with the increasing demand of food from animal sources, excessive loss due to myopathies and other muscular dystrophies was found detrimental as it aggravates diseases that result in increased morbidity and mortality. Holding key point towards improving the developmental program of muscle in meat producing animals, elucidating the underlying mechanisms of the associated pathways in livestock animals is believed to open up new avenues towards enhancing the lean tissue deposition. To this end, identification of vital candidate genes having no known function in myogenesis, is believed to increase the current understanding of the physiological processes going on in the skeletal muscle tissue. Taking consequences of gene expression changes into account, knowledge of the pathways associated with their activation and as such up-regulation seems critical for the overall muscle homeostasis. Having important implications on livestock production, a thorough understanding of postnatal muscle development seems a timely step to fulfil the growing need of ever increasing populations of the world.

• IMMUNE NETWORK
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• v.10 no.4
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• pp.126-134
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• 2010

Background: $CD8^+$ T cells contribute to the clearance of Hepatitis B virus (HBV) infection and an insufficient $CD8^+$ T cell response may be one of the major factors leading to chronic HBV infection. Since the HBx antigen of HBV can up-regulate cellular expression of several immunomodulatory molecules, we hypothesized that HBx expression in hepatocytes might affect $CD8^+$ T cell activity. Methods: We analyzed the activation and apoptosis of $CD8^+$ T cells co-cultured with primary hepatocytes rendered capable of expressing HBx by recombinant baculovirus infection. Results: Expression of HBx in hepatocytes induced low production of $interferon-{\gamma}$ and apoptosis of CD8+ T cells, with no effect on CD8 T cell proliferation. However, transcriptional levels of H-2K, ICAM-1 and PD-1 ligand did not correlate with HBx expression in hepatocytes. Conclusion: Our results suggest that HBx may inhibit $CD8^+$ T cell response by regulation of $interferon-{\gamma}$ production and apoptosis.

• Carbon letters
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• v.15 no.3
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• pp.198-202
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• 2014

Amorphous agglomerates of carbon nanospheres (CNS) with a diameter range of 10-50 nm were synthesized using the solution combustion method. High-resolution transmission electron microscopy (HRTEM) revealed a densely packed high surface area of $SP^2$-hybridized carbon; however, there were no crystalline structural components, as can be seen from the scanning electron microscopy, HRTEM, X-ray diffraction, Raman spectroscopy, and thermal gravimetric analyses. Electrochemical and thermo catalytic decomposition study results show that the material can be used as a potential electrode candidate for the fabrication of energy storage devices and also for the production of free hydrogen if such devices are used in a fluidized bed reactor loaded with the as-prepared CNS as the catalyst bed.

• Bulletin of the Korean Chemical Society
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• v.20 no.1
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• pp.35-41
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• 1999

Stability characteristics of hyperbolic reaction-diffusion equations with a reversible Brusselator model are investigated as an extension of the previous work. Intensive stability analysis is performed for three important parameters, Nrd, β and Dx, where Nrd is the reaction-diffusion number which is a measure of hyperbolicity, β is a measure of reversibility of autocatalytic reaction and Dx is a diffusion coefficient of intermediate X. Especially, the dependence on Nrd of stability exhibits some interesting features, such as hyperbolicity in the small Nrd region and parabolicity in the large Nrd region. The hyperbolic reaction-diffusion equations are solved numerically by a spectral method which is modified and adjusted to hyperbolic partial differential equations. The numerical method gives good accuracy and efficiency even in a stiff region in the case of small Nrd, and it can be extended to a two-dimensional system. Four types of solution, spatially homogeneous, spatially oscillatory, spatio-temporally oscillatory and chaotic can be obtained. Entropy productions for reaction are also calculated to get some crucial information related to the bifurcation of the system. At the bifurcation point, entropy production changes discontinuously and it shows that different structures of the system have different modes in the dissipative process required to maintain the structure of the system. But it appears that magnitude of entropy production in each structure give no important information related for states of system itself.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.2
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• pp.59-66
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• 1989

Growing and finishing Korean native bulls were used to investigate the effects of different dietary energy levels on performance and energy intake. Experimental observations were made over three weight categories (200 to 250 kg, 250 to 350 kg and 350 to 450 kg). Three diets (2.4, 2.6 and 2.8 Mcal ME/kg DM) were used for each weight category. Crude protein levels of the diets were 12, 11 and 10% for the respective weight groups. Dietary energy level did not significantly affect daily body gain within a weight range but daily body gain during the entire experiment was higher (P<.05) in bulls receiving 2.6 Mcal energy diet than in those fed 2.4 and 2.8 Mcal energy diets. The following equation was developed to predict daily body gain(Y) from energy levels(X) of ration. $Y\;=\;1.3.475X\;-\;2.5949X^{2}\;-\;16.355$ Increasing energy levels significantly (P<.05) decreased daily feed intake. The following equation was developed to predict daily feed intake(Y) from energy levels(X) of ration. $Y\;=\;-30.013X\;+\;5.4401X^{2}\;+\;49.119$ Feed intake per metabolic body size during the entire feeding period ranged from 100.9 to 110.8 g and was lower in bulls fed 2.6 and 2.8 Mcal energy diets than in those fed 2.4 Mcal energy diet. Increasing energy levels significantly (P<.05) improved feed efficiency. The following equation was developed to predict feed efficiency(Y) from energy levels(X) of ration. $Y\;=\;-118.34X\;+\;22.448X^{2}\;+\;162.85$ Daily energy intake during the entire experiment ranged from 18.90 to 19.99 Mcal and there was no significant difference among energy levels. Daily energy intake per metabolic body size during the feeding period ranged from 248.6 to 260.8 kcal and was slightly higher in bulls receiving 2.8 Mcal than in those fed 2.4 and 2.6 Mcal energy diets. Energy required per kg body gain ranged from 17.25 to 19.11 Mcal and was slightly lower in bulls receiving 2.6 Mcal energy diet than in those fed 2.4 and 2.8 Mcal energy diets.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.10 no.16
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• pp.101-106
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• 1987

Statistical control charts are useful tools to monitor and control the manufacturing processes and are widely used in most Korean industries. Many Korean companies, however, do not always obtain desired results from the traditional control charts by Shewhart such as the $\bar{X}$-chart, $\bar{X}$-chart, $\bar{X}$-chart, etc. This is partly because the quality charterstics of the process are not distributed normally but are skewed due to the intermittent production, small lot size, etc. In Shewhart $\bar{X}$-chart. which is the most widely used one in Kora, such skewed distributions make the plots to be inclined below or above the central line or outside the control limits although no assignable causes can be found. To overcome such shortcomings in nonnormally distributed processes, a distribution-free type of confidence interval can be used, which should be based on order statistics. This thesis is concerned with the design of control chart based on a sample median which is easy to use in practical situation and therefore properties for nonnormal distributions may be easily analyzed. Control limits and central lines are given for the more famous nonnormal distributions, such as Gamma, Beta, Lognormal, Weibull, Pareto, Truncated-normal distributions. Robustness of the proposed median control chart is compared with that of the $\bar{X}$-chart; the former tends to be superior to the latter as the probability distribution of the process becomes more skewed. The average run length to detect the assignable cause is also compared when the process has a Normal or a Gamma distribution for which the properties of X are easy to verify, the proposed chart is slightly worse than the $\bar{X}$-chart for the normally distributed product but much better for Gamma-distributed products. Average Run Lengths of the other distributions are also computed. To use the proposed control chart, the probability distribution of the process should be known or estimated. If it is not possible, the results of comparison of the robustness force us to use the proposed median control chart based oh a normal distribution. To estimate the distribution of the process, Sturge's formula is used to graph the histogram and the method of probability plotting, $\chi$$^2$-goodness of fit test and Kolmogorov-Smirnov test, are discussed with real case examples. A comparison of the proposed median chart and the $\bar{X}$ chart was also performed with these examples and the median chart turned out to be superior to the $\bar{X}$-chart.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.4
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• pp.471-478
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• 2011

The objectives were to compare the ability of various rumen microbial fractions to reduce nitrate and to assess the effect of nitrate on in vitro fermentation characteristics. Physical and chemical methods were used to differentiate the rumen microbial population into the following fractions: whole rumen fluid (WRF), protozoa (Pr), bacteria (Ba), and fungi (Fu). The three nitrogen substrate treatments were as follows: no supplemental nitrogen source, nitrate or urea, with the latter two being isonitrogenous additions. The results showed that during 24 h incubation, WRF, Pr and Ba fractions had an ability to reduce nitrate, and the rate of nitrate disappearance for the Pr fraction was similar to the WRF fraction, while the Ba fraction needed an adaptation period of 12 h before rapid nitrate disappearance. The WRF fraction had the greatest methane ($CH_4$) production and the Pr fraction had the greatest prevailing $H_2$ concentration (p<0.05). Compared to the urea treatment, nitrate diminished net gas and $CH_4$ production during incubation (p<0.05), and ammonia-N ($NH_3$-N) concentration (p<0.01). Nitrate also increased acetate, decreased propionate and decreased butyrate molar proportions (p<0.05). The Pr fraction had the highest acetate to propionate ratio (p<0.05). The Pr fraction as well as the Ba fraction appears to have an important role in nitrate reduction. Nitrate did not consistently alter total VFA concentration, but it did shift the VFA profile to higher acetate, lower propionate and lower butyrate molar proportions, consistent with less $CH_4$ production by all microbial fractions.

• Journal of the Korean Institute of Gas
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• v.25 no.2
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• pp.1-12
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• 2021

MILD(Moderate or Intense Low-oxygen Dilution) combustion has attracted attention as the clean thermal energy technology due to the lower emissions of unburnt carbon and NO_x. MILD combustion aims to enlarge the combustion reaction zone using the spontaneous ignition phenomenon of the reactants. In this study, the ignition delay time of CH₄ according to the initial temperature of reactants and the addition of CO, H₂ was investigated using a numerical approach. Ignition delay time became shorter as the increases of initial temperature and H₂ addition. But, CO addition to the fuel increase the ignition delay time. In case of H₂ addition to the fuel, the ignition delay time decreased because the higher fraction of HO₂ promotes the decomposition of methyl radical(CH₃) and produce OH radical. However, in case of CO addition to the fuel, ignition delay time inceased because a high proportion of HCO consumes H radical. There was no significant effect of HCO on the reduction of ignition delay time. Also, the increase rates of NO emissions by the addition of CO and H₂ were approximately 7% and 1%, respectively. A high proportion of NCO affects the increase in NO production rate.

• Microbiology and Biotechnology Letters
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• v.46 no.2
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• pp.120-126
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• 2018

As a basic study for environment-friendly production of bacterial cellulose (BC) dressing with antimicrobial activity, we isolated and identified acetic acid bacteria which are resistant to silver ions and can biosynthesize silver nanoparticles. Furthermore, conditions of BC production by selected strain were also investigated. Strain G7 isolated from decayed grape skin was able to grow in the presence of 0.1 mM $AgNO_3$ which was identified as Acetobacter intermedius based on 16S rRNA gene analysis. BC production was the highest in a medium containing 2% glucose as a carbon source, 2% yeast extract as a nitrogen source, and 0.115% acetic acid as a cosubstrate. Structural properties of BC produced in optimal medium were studied using Fourier-transform infrared spectroscopy and X-ray diffractometer, and it was found that BC produced was cellulose type I that was the same as a typical native cellulose. When strain G7 was cultured in an optimal medium containing 0.1 mM $AgNO_3$, the color of the culture broth turned into reddish brown, indicating that silver nanoparticles were formed. As a result of UV-Vis spectral analysis of the culture, it was found that a unique absorption spectrum of silver nanoparticles at 425 nm was also observed. Scanning electron microscopic observations showed that silver nanoparticles were formed on the surface and pores of BC membrane.