• Korean Chemical Engineering Research
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• v.47 no.4
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• pp.470-475
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• 2009

To study the optimal synthesis conditions of aqueous acrylic adhesive using emulsion polymerization, the effects of monomer, surfactant and initiator on the adhesive properties, such as conversion rate, particle size, peel strength, and glass transition temperature, were investigated. 2-EHA, n-BA and MMA were used as main monomers, 2-HEMA and AAc as functional monomers, SLS as surfactant and APS as initiator, respectively. The conversion rate was over 95% at 3.75% surfactant(SLS/monomer), 0.612% initiator(APS/monomer) and $82^{\circ}C$ reaction temperature. When the excess amount of surfactant or initiator was used, the peel strength represented decreasing tendency. The maximum conversion rate and peel strength were obtained at 65% 2-EHA/monomer, 20% BA/monomer, and 10% MMA/monomer.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.477-481
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• 2004

High Quality CD, OAT audio requires that large amount of data. Currently, multi channel preference has been rapidly propagated among latest users. The MPEG(Moving Picture Expert Group) is provides data compression technology of sound and image system. The MPEG standard provides multi channel and 5.1 sounds, using the same audio algorithm as MPEG-l. And MPEG-2 audio is forward and backward compatible. The MDCT (Modified Discrete Cosine Transform) is a linear orthogonal lapped transform based on the idea of TDAC(Time Domain Aliasing Cancellation). In this paper, we proposed the micro-program type vector processor architecture a benefit in MDCT/IMDCT of MPEG-II AAC. And it's reduced operating coefficient by overlapped area to bind. To compare original algorithm with optimized algorithm that cosine coefficient reduced $0.5\%$multiply operating $0.098\%$ and add operating 80.58\%$. Algorithm test is used C-language then we designed hardware architecture of micro-programmed method that applied to optimized algorithm. This processor is 20MHz operation 5V.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.185-190
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• 2014

The aim of this study was to investigate the prevalence of quinolone resistant E. coli from raw bulk milk and to characterize the resistance determinants. In this study, the gyrA, gyrB, parC, and parE quinolone resistance determining regions (QRDR) were sequenced from quinolone resistant E. coli isolates. Also, the presence of plasmid-mediated quinolone resistance (PMQR) and the expression of efflux pump genes based on quantitative real-time PCR (qRT-PCR) were investigated. Of the 487 coliform bacteria, 9 strains showed nalidixic acid resistance, and 6 of the 9 nalidixic acid resistant isolates were also ciprofloxacin resistant. These 9 strains had a single mutation at codon 83 (S83L) in gyrA, 2 of them had double mutations at codon 83 and 87 (S83L and D87N) in gyrA and 3 of the 9 isolates had single mutations at codon 80 (S80I) in parC. None of the 9 isolates harbored PMQR determinants. Compared with wild-type E. coli ATCC 25922, an over-expression of the acrB gene (2.15-5.74 fold), encoding the pump component of the AcrAB-TolC efflux pump was observed in 4 of 6 ciprofloxacin resistant isolates. This study identified the quinolone resistance mechanism of E. coli isolated from raw milk samples in Gyeonggi-do.

• Journal of Veterinary Science
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• v.23 no.1
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• pp.9.1-9.11
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• 2022

Background: Escherichia coli, which causes subclinical or clinical mastitis in cattle, is responsible for transmitting antimicrobial resistance via human consumption of raw milk or raw milk products. Objectives: The objective of this study was to investigate the molecular characteristics of 183 E. coli from bulk tank milk of five different dairy factories in Korea. Methods: The molecular characteristics of E. coli such as serogroup, virulence, antimicrobial resistance, and integron genes were detected using polymerase chain reaction and antimicrobial susceptibility were tested using the disk diffusion test. Results: In the distribution of phylogenetic groups, group D was the most prevalent (59.6%) and followed by group B1 (25.1%). The most predominant serogroup was O173 (15.3%), and a total of 46 different serotypes were detected. The virulence gene found most often was fimH (73.2%), and stx1, fimH, incC, fyuA, and iutA genes were significantly higher in isolates of phylogenetic group B1 compared to phylogenetic groups A, B2, and D (p < 0.05). Among 64 E. coli isolates that showed resistance to at least one antimicrobial, the highest resistance rate was observed for tetracyclines (37.5%). All 18 integron-positive E. coli carried the integron class I (int1) gene, and three different gene cassette arrangements, dfrA12+aadA2 (2 isolates), aac(6')-Ib3+aac(6')-Ib-cr+aadA4 (2 isolates), and dfrA17+aadA5 (1 isolate) were detected. Conclusions: These data suggest that the E. coli from bulk tank milk can be an indicator for dissemination of antimicrobial resistance and virulence factors via cross-contamination.

• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.269-277
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• 2013

In this study, we present results of precise orbital geodetic parameter estimation using satellite laser ranging (SLR) observations for the International Laser Ranging Service (ILRS) associate analysis center (AAC). Using normal point observations of LAGEOS-1, LAGEOS-2, ETALON-1, and ETALON-2 in SLR consolidated laser ranging data format, the NASA/GSFC GEODYN II and SOLVE software programs were utilized for precise orbit determination (POD) and finding solutions of a terrestrial reference frame (TRF) and Earth orientation parameters (EOPs). For POD, a weekly-based orbit determination strategy was employed to process SLR observations taken from 20 weeks in 2013. For solutions of TRF and EOPs, loosely constrained scheme was used to integrate POD results of four geodetic SLR satellites. The coordinates of 11 ILRS core sites were determined and daily polar motion and polar motion rates were estimated. The root mean square (RMS) value of post-fit residuals was used for orbit quality assessment, and both the stability of TRF and the precision of EOPs by external comparison were analyzed for verification of our solutions. Results of post-fit residuals show that the RMS of the orbits of LAGEOS-1 and LAGEOS-2 are 1.20 and 1.12 cm, and those of ETALON-1 and ETALON-2 are 1.02 and 1.11 cm, respectively. The stability analysis of TRF shows that the mean value of 3D stability of the coordinates of 11 ILRS core sites is 7.0 mm. An external comparison, with respect to International Earth rotation and Reference systems Service (IERS) 08 C04 results, shows that standard deviations of polar motion $X_P$ and $Y_P$ are 0.754 milliarcseconds (mas) and 0.576 mas, respectively. Our results of precise orbital and geodetic parameter estimation are reasonable and help advance research at ILRS AAC.

• Journal of Veterinary Science
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• v.22 no.6
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• pp.78.1-78.10
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• 2021

Background: Recurrent subclinical mastitis (RScM) due to resistant bacteria has low clinical and bacteriological cure rates, often requiring the culling of cows. The sequential intramammary administration of enrofloxacin hydrochloride-dihydrate (enro-C) followed by ceftiofur HCl may be useful for treating these cases. Objectives: This study assessed the bacteriological and clinical cure-efficacies of the sequentially intramammary administration of enro-C, followed by ceftiofur HCl to treat RScM in Holstein/Friesian cows. Methods: This trial was conducted in a herd with a high prevalence of RScM, and 20 Holstein/Friesian cows were included: 45% suffering subclinical mastitis and 38.9% of the mammary quarters affected. Twenty-nine bacterial isolates in vitro resistant to enro-C were obtained (coagulase-negative Staphylococcus spp, 55.2%; Staphylococcus aureus, 27.6%; Escherichia coli, 6.9%; Streptococcus uberis, 6.9%; Corynebacterium bovis, 3.4%). Polymerase chain reaction-isolated the following genes linked to enro-C resistance: chromosomal (gyrA) and plasmid (aac(6')-lb-cr). The treatments were as follows: twice-daily intramammary infusions of enro-C (300 mg/10 mL) for 5 days. Cows clinically considered treatment failures were also treated with intramammary ceftiofur (125 mg/10 mL, twice daily for 5 days. The clinical and bacteriological cure rates were carried out when completing each treatment phase and at 14 and 21 days, aided by a California mastitis test, somatic cell count, and failure to identify the initially causative bacteria. Results: Enro-C achieved 65% clinical and bacteriological cure rates, and 100% cure rates were obtained after the rescue treatment with ceftiofur HCl. Conclusions: Outstanding clinical and bacteriological cure rates in cows affected by RScM were achieved with the consecutive intramammary infusions of enro-C, followed by ceftiofur HCl.

• Biomedical Science Letters
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• v.26 no.2
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• pp.120-126
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• 2020

Fluoroquinolone (FQ) resistant uropathogenic Escherichia coli (UPEC) have become a major problem in urinary tract infections (UTIs). The purpose of this study was to compare the quinolone resistance-determining region (QRDR) and plasmid mediated quinolone resistance (PMQR) determinants of FQ resistant UPEC between 1989 and 2010-2014. A total of 681 strains of UPEC clinical isolates was collected from Korean healthcare facility in 1989 (123 strains) and in 2010-2014 (558 strains). The minimum inhibitory concentrations (MICs) of FQs were determined by agar dilution method. QRDRs (gyrA, gyrB, parC and parE) and PMQR determinants (qnrA, qnrB, qnrS, aac(6')-Ib-cr and qepA) were analyzed polymerase chain reaction and sequencing method. Among 681 isolates, FQ resistant UPEC were 3 strains (2.4%) in 1989 isolates and 220 strains (39.4%) in 2010-2014 isolates. The rate of the FQ resistant UPEC strains in 2010-2014 isolates was increased than that of in 1989 isolates. UPEC isolates from 1989 and 2010-2014 were shown to carry mutations in gyrA (Ser83 and Asp87), gyrB (Ser464 and Thr469), parC (Ser80 and Glu84) and parE (Glu460, Ser458, Ile464 and Leu445). The most common mutations of QRDRs in 1989 isolates were Ser83Leu and Asp87Gly in gyrA and Ser80Ile in parC (2 strains: 66.7%) while those in 2010-2014 isolates were Ser83Leu and Asp87Asn in gyrA and Ser80Il2 and Glu84Val in parC (88 strains: 40.0%). PMQR determinants were detected only in 2010-2014 UPEC strains (47 strains: 21.4%).

• Korean Journal of Clinical Laboratory Science
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• v.47 no.2
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• pp.65-70
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• 2015

Antimicrobial agents or additives have commonly been used in domestic animals for the prevention and treatment of bacterial diseases. Unfortunately, this has resulted in the overgrowth of bacteria that is resistant to antimicrobial agents used by humans, and these might get disseminated to humans via the food. In this study, we investigated the prevalence of integrons, and characterized gene cassette arrays in Proteus mirabilis isolates obtained from chickens in Chungcheong province of Korea. Additionally, the correlation between gene cassette arrays and antimicrobial resistance rate was studied. A total of 26 Proteus mirabilis isolates were recovered from chickens in Chungcheong province in Korea. Antimicrobial susceptibility was determined by disk diffusion method. PCR and DNA sequencing were performed to characterize the gene cassette arrays. In addition, we employed repetitive extragenic palindromic sequence-based PCR (REP-PCR) method for clonality analysis of P. mirabilis strains. Of the 26 P. mirabilis isolates tested, 14 (53.8%) isolates carried class 1 integrons, while class 2 and class 3 integrons were not detected in our study. The class 1 integrons harbored genes encoding resistance to aminoglycosides (aacCA5, aadA2, aadA5 and aadA7), trimethoprim (dfrA17, and dfrA32), lincosamides (linF) and erythromycin (ereA). In particular, the presence of class 1 integron had a significant correlatation to a high resistance rate of aminoglycoside and trimethoprim. We confirmed that class 1 integrons are widely disseminated in P. mirabilis isolates from chickens, contributing to the resistance to diverse antimicrobial agents in Korea. To prevent further spreading of antimicrobial resistant genes among P. mirabilis isolates, constant monitoring and clinical policing will become necessary.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.349-355
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• 2017

The amino acid composition of rice is a major concern of rice breeders because amino acids are among the most important nutrient components in rice. In this study, a genetic map was constructed with a population of 134 recombinant inbred lines (RILs) from a cross between Dasanbyeo (Tongil-type indica) and TR22183 (temperate japonica), as a means to detect the main and epistatic effect quantitative trait loci (QTLs) for the amino acid content (AAC). Using a linkage map which covered a total of 1458 cM based on 239 molecular marker loci, a total of six main-effect QTLs (M-QTLs) was identified for the content of six amino acids that were mapped onto chromosome 3. For all the M-QTLs, the TR22183 allele increased the trait values. The QTL cluster (flanked by id3015453 and id3016090) on chromosome 3 was associated with the content of five amino acids. The phenotypic variation, explained by the individual QTLs located in this cluster, ranged from 10.2 to 12.4%. In addition, 26 epistatic QTLs (Ep-QTLs) were detected and the 25 loci involved in this interaction were distributed on all nine chromosomes. Both the M-QTLs and Ep-QTLs detected in this study will be useful in breeding programs which target the development of rice with improved amino acid composition.

• The Korean Journal of Food And Nutrition
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• v.33 no.3
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• pp.223-236
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• 2020

In this study, a safety evaluation was conducted to confirm if the Enterococcus faecium CKDB003 strain obtained by selection from a mixed fermentation of fruit and milk is suitable for use as a probiotic. The MIC value for the 10 antibiotics specified in the EFSA guidance was below the acceptable cut-off value. The antibiotic resistance genes aac(6')-li, eatAv, and msr(C) exist by whole genome sequencing, but are in the chromosome and not in the plasmid, thus confirming that there is no possibility of transmission to other microorganisms. It was confirmed that cytolysin (cylA, cylB, cylI, cylL-l, cylL-s, cylM, cylR1, cylR2), aggregation substance (asa1, asp1), collagen adhesion (ace), enterococcal surface protein (esp), endocarditis antigen (efaA), hyaluronidase (hyl) and gelatinase (gelE) were not present in the genome by examining the genes of factors related to virulence. Also, the biochemical analysis showed no toxic enzyme activities, and no virulence genes were detected by the PCR method. Thus, the E. faecium CKDB003 strain can be safely used as a health functional food probiotic, based on the results of the safety assessment.