• The Journal of the Korean dental association
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• v.58 no.10
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• pp.615-626
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• 2020

The outbreak of COVID-19, caused by SARS-CoV-2 infection, has spread worldwide and resulted in a pandemic for health systems. The disease is transmitted via respiration as droplets or aerosol. Due to the nature of dental treatment, aerosols, including body fluid, blood, and saliva, are frequently produced in dental hospitals. The present study investigated the potential risk of nosocomial infection of COVID-19 in dental hospitals to provide recommendations in clinical situations. The Seoul National University Dental Hospital in Korea established a countermeasure to cope with the clinical situation based on The Guidelines of Korean Centers for Disease Control & Prevention (KCDC) for dental practitioners and the available literature. Notably, numerous considerations for patient reservation and schedule management are required for space separation in the hospital, including infection control. Experiences in dental hospitals in Korea would be referable for other dental hospitals facing this infectious respiratory disease.

• Korean Journal of Materials Research
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• v.28 no.7
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• pp.391-397
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• 2018

This study deals with the microstructure and tensile properties of 700 MPa-grade high-strength and seismic reinforced steel bars. The high-strength reinforced steel bars (600 D13, 600 D16 and 700 D13 specimens) are fabricated by a TempCore process, while the seismic reinforced steel bar (600S D16 specimen) is fabricated by air cooling after hot rolling. For specimens fabricated by the TempCore process, the 600 D13 and 600 D16 specimens have a microstructure of tempered martensite in the surface region and ferrite-pearlite in the center region, while the 700 D13 specimen has a microstructure of tempered martensite in the surface region and bainite in the center region. Therefore, their hardness is the highest in the surface region and shows a tendency to decrease from the surface region to the center region because tempered martensite has a higher hardness than ferrite-pearlite or bainite. However, the hardness of the 600S D16 specimen, which is composed of fully ferrite-pearlite, increases from the surface region to the center region because the pearlite volume fraction increases from the surface region to the center region. On the other hand, the tensile test results indicate that only the 700 D13 specimen with a higher carbon content exhibits continuous yielding behavior due to the formation of bainite in the center region. The 600S D16 specimen has the highest tensile-to-yield ratio because the presence of ferrite-pearlite and precipitates caused by vanadium addition largely enhances work hardening.

• Proceedings of the Korean Society of Veterinary Clinics Conference
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• 2008.05a
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• pp.101-101
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• 2008

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.9
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• pp.1345-1354
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• 2014

Copy number variations (CNVs), important genetic factors for study of human diseases, may have as large of an effect on phenotype as do single nucleotide polymorphisms. Indeed, it is widely accepted that CNVs are associated with differential disease susceptibility. However, the relationships between CNVs and gene expression have not been characterized in the horse. In this study, we investigated the effects of copy number deletion in the blood and muscle transcriptomes of Thoroughbred racing horses. We identified a total of 1,246 CNVs of deletion polymorphisms using DNA re-sequencing data from 18 Thoroughbred racing horses. To discover the tendencies between CNV status and gene expression levels, we extracted CNVs of four Thoroughbred racing horses of which RNA sequencing was available. We found that 252 pairs of CNVs and genes were associated in the four horse samples. We did not observe a clear and consistent relationship between the deletion status of CNVs and gene expression levels before and after exercise in blood and muscle. However, we found some pairs of CNVs and associated genes that indicated relationships with gene expression levels: a positive relationship with genes responsible for membrane structure or cytoskeleton and a negative relationship with genes involved in disease. This study will lead to conceptual advances in understanding the relationship between CNVs and global gene expression in the horse.

• Korean Journal of Biological Psychiatry
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• v.19 no.3
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• pp.140-145
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• 2012

Objectives : ST8SIA2 (ST8 alpha-N-acetyl-neuraminide alpha-2, 8-sialyltransferase 2 gene) is located at 15q26, a susceptibility locus for schizophrenia. Some previous research had indicated that single-nucleotide polymorphisms (SNPs) in the promoter region of ST8SIA2 were associated with schizophrenia in Japanese and Chinese populations. We investigated the association between SNPs in the promoter region of ST8SIA2 and schizophrenia in the Korean population. Methods : The study subjects were 190 Korean patients with schizophrenia and 190 healthy controls. We performed allelic, genotypic, and haplotypic association analyses for rs3759916, rs3759915 and rs3759914 of ST8SIA2. All genotypes were determined by direct sequencing. Results : In the genotype-based analysis, rs3759914 showed a nominally significant association with schizophrenia under recessive genotypic model (p = 0.047). However, this association did not remain statistically significant after correction for multiple testing. Both allelic and haplotype analyses did not show any significant association. Conclusions : These findings suggest that ST8SIA2 does not play a major role in the susceptibility to schizophrenia in the Korean population. Further studies with a larger number of subjects are required to definitively rule out minor effects of this gene on schizophrenia vulnerability.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.598-606
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• 2003

Salmonella encodes an enterotoxin (Stn) which possesses biological activity similar to the cholera toxin. Stn contributes significantly to the overall virulence of S. typhimurium in a murine model. The production of Stn is enhanced in a high-osmolarity medium and by contact with epithelial cells. In the present study, the in vitro and in vivo transcriptional regulations of the sin promoter revealed two promoters, P1 and P2. The P1 promoter identified by a primer extension analysis of stn mRNA exhibited a switching mechanism in vivo. Depending on the growth stage, transcription was initiated from different start sites termed $P1_S\;and\;P1_E$. $P1_S$, recognized by RNA polymerase containing ${\sigma}^S(E{\sigma}^S),\;and\;P1_E$, recognized by $E{\sigma}^70$, were activated during the stationary and exponential phases, respectively, while $P1_S\;and\;P1_E$ were both negatively regulated by CRPㆍcAMP and H-NS. Results revealed that $P1_S$ was the responsible promoter activated under a high osmolarity and low pH. The P2 promoter was identified 45 nucleotides downstream from $P1_E$ and negatively controlled by CRPㆍcAMP in vitro. No P2 activity was detected in vivo. The regulation of stn expression monitored using a Pstn::egfp fusion indicated that $E{\sigma}^S$ was required for the induction of stn and various factors were involved in stn regulation inside animal cells.

• Applied Biological Chemistry
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• v.37 no.5
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• pp.385-391
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• 1994

The occurrence of Fusarium mycotoxins was surveyed in 68 corn samples imported from China. Four 8-ketotrichothecenes including deoxynivalenol (DON), 15-acetyldeoxynivalenol (15-ADON), 3-acetyldeoxynivalenol (3-ADON), and nivalenol (NIV) were detected in corn. In addition, the corn samples were contaminated with zearalenone (ZEA), fumonisin $B_1$, $(FB_1)$, fumonisin $B_2$, and fumonisin $B_3$. DON, 15-ADON, 3-ADON, ZEA, and $FB_1$ were major contaminants in corn, with mean levels of 277, 34, 37, 39, and 123 ng/g, respectively.

• Journal of Korean Neurosurgical Society
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• v.43 no.2
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• pp.97-104
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• 2008

Objective: Transient receptor potential vanilloid subfamily type 1 (TRPV1), a most specific marker of the nociceptive primary afferent, is expressed in peptidergic and non-peptidergic primary afferents innervating skin and viscera. However, its expression in sensory fibers to skeletal muscle is not well known. In this study, we studied the neurochemical characteristics of TRPV1-positive primary afferents to skeletal muscles. Methods: Sprague-Dawley rats were injected with total $20{\mu}l$ of 1% fast blue (FB) into the gastrocnemius and erector spinae muscle and animals were perfused 4 days after injection. FB-positive cells were traced in the L4-L5 (for gastrocnemius muscle) and L2-L4 (for erector spinae muscle) dorsal root ganglia. The neurochemical characteristics of the muscle afferents were studied with multiple immunofluorescence with TRPV1, calcitonin gene-related peptide (CGRP) and $P2X_3$. To identify spinal neurons responding to noxious stimulus to the skeletal muscle, 10% acetic acids were injected into the gastrocnemius and erector spinae muscles and expression of phospho extracellular signal-regulated kinase (pERK) in spinal cords were identified with immunohistochemical method. Results: TRPVl was expressed in about 49% of muscle afferents traced from gastrocnemius and 40% of erector spinae. Sixty-five to 60% of TRPV1-positive muscles afferents also expressed CGRP. In contrast, expression of $P2X_3$ immnoreaction in TRPV1-positive muscle afferents were about 20%. TRPV1-positive primary afferents were contacted with spinal neurons expressing pERK after injection of acetic acid into the muscles. Conclusion: It is consequently suggested that nociception from skeletal muscles are mediated by TRPV1-positive primary afferents and majority of them are also peptidergic.

• Proceedings of the KSCN Conference
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• 2005.04a
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• pp.160-161
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• 2005

• IE interfaces
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• v.20 no.1
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• pp.21-32
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• 2007

This paper deals with the simulation model for A-Mart logistic center design and operations. In developed simulation model, receiving docks, conveyor sorter, conveyor system, shipping docks, material handling devices and manual sorting stations are considered. Three types of cargo such as transfer center cargo, distribution center cargo and supermarket cargo are considered. The simulation model and process animation are developed using the simulation package ARENA. Among various design and operation alternatives consisting of the number of workers of receiving dock, allocation of receiving docks by cargo types, conveyor sorter velocity, the number of folk-lift, the number of manual sorting operators and overall layout, the best alternatives of each subsystem are selected by simulation analysis. The major performance measures such as sorter throughput, utilization of operators at each station, receiving docks utilization and folk-lift utilization are considered for the alternative evaluation.