• Journal of the Korean Mathematical Society
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• v.34 no.4
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• pp.949-957
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• 1997

The purpose of this paper is to establish connection between certain complex of modules of generalized fractions and the concept of cosequence in commutative algebra. The main theorem of the paper leads to characterization, in terms of modules of generalized fractions, of regular (co) sequences.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.76-76
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• 2013

The current hierarchical model of galaxy formation predicts that galaxy halos contain merger relics in the form of long stellar streams. In order to find stellar substructures in galaxy, we focused our investigation on the stellar spatial density around globular clusters and on the quantitative properties of the evolved sequences in the color-magnitude diagrams (CMDs). First, we investigated the spatial configuration of stars around five metal-poor globular clusters in halo region (M15, M30, M53, NGC 5053, and NGC 5466) and one metal-poor globular cluster in bulge region (NGC 6626). Our findings indicate that all of these globular clusters show strong evidence of extratidal features in the form of extended tidal tails around the clusters. The orientations of the extratidal features show the signatures of tidal tails tracing the clusters' orbits and the effects of dynamical interactions with the galaxy. These features were also confirmed by the radial surface density profiles and azimuthal number density profiles. Our results suggest that these six globular clusters are potentially associated with the satellite galaxies merged into the Milky Way. Second, we derived the morphological parameters of the red giant branch (RGB) from the near-infrared CMDs of 12 metal-poor globular clusters in the Galactic bulge. The photometric RGB shape indices such as colors at fixed magnitudes, magnitudes at fixed colors, and the RGB slope were measured for each cluster. The magnitudes of the RGB bump and tip were also estimated. The derived RGB parameters were used to examine the overall behavior of the RGB morphology as a function of cluster metallicity. The behavior of the RGB shape parameters was also compared with the previous observational calibration relation and theoretical predictions of the Yonsei-Yale isochrones. Our results of studies for stellar spatial distribution around globular clusters and the morphological properties of RGB stars in globular clusters could add further observational evidence of merging scenario of galaxy formation.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.9
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• pp.4395-4399
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• 2016

The FLT3-ITD mutation is one of the most frequent genetic abnormalities in acute myeloid leukemia (AML) where it is associated with a poor prognosis. The FLT3-ITD mutation could, therefore, be a potential molecular prognostic marker important for risk-stratified treatment options. We amplified the FLT3 gene at exon 14 and 15 in 52 AML patients (aged between 2 months and 74 years) from 4 referral centers (a university hospital and 3 regional hospitals in Northeast Thailand), using a simple PCR method. FLT3-ITD mutations were found in 10 patients (19.2%), being more common in adults than in children (21.1% vs. 14.3%) and more prevalent in patients with acute promyelocytic leukemia (AML-M3) than AML-non M3 (4 of 10 AML-M3 vs. 6 of 42 AML-non M3 patients). Duplication sequences varied in size-between 27 and 171 nucleotides (median=63.5) and in their location. FLT3-ITD mutations with common duplication sequences accounted for a significant percentage in AML patients in northeastern Thailand. This simple PCR method is feasible for routine laboratory practice and these data could help tailor use of the national protocol for AML.

• Journal of Microbiology and Biotechnology
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• v.33 no.12
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• pp.1692-1697
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• 2023

Staphylococcus aureus integrated with mecA gene, which codes for penicillin-binding protein 2a, is resistant to all penicillins and other beta-lactam antibiotics, resulting in poor treatment expectations in skin and soft tissue infections. The development of a simple, sensitive and portable biosensor for mecA gene analysis in S. aureus is urgently needed. Herein, we propose a dual-toehold-probe (sensing probe)-mediated exonuclease-III (Exo-III)-assisted signal recycling for portable detection of the mecA gene in S. aureus. When the target mecA gene is present, it hybridizes with the sensing probe, initiating Exo III-assisted dual signal recycles, which in turn release numerous "3" sequences. The released "3" sequences initiate catalytic hairpin amplification, resulting in the fixation of a sucrase-labeled H2 probe on the surface of magnetic beads (MBs). After magnet-based enrichment of an MB-H1-H2-sucrase complex and removal of a liquid supernatant containing free sucrase, the complex is then used to catalyze sucrose to glucose, which can be quantitatively detected by a personal glucose meter. With a limit of detection of 4.36 fM for mecA gene, the developed strategy exhibits high sensitivity. In addition, good selectivity and anti-interference capability were also attained with this method, making it promising for antibiotic tolerance analysis at the point-of-care.

• The Journal of the Acoustical Society of Korea
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• v.14 no.5
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• pp.5-10
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• 1995

In this paper we present a clustering procedure based on the use of HMM in order to get multiple statistical models which can well absorb the variants of each speaker with different ways of saying words. The HMM-clustered models obtained from the developed technique are applied to the speaker independent isolated word recognition. The HMM clustering method splits off all observation sequences with poor likelihood scores which fall below threshold from the training set and create a new model out of the observation sequences in the new cluster. Clustering is iterated by classifying each observation sequence as belonging to the cluster whose model has the maximum likelihood score. If any clutter has changed from the previous iteration the model in that cluster is reestimated by using the Baum-Welch reestimation procedure. Therefore, this method is more efficient than the conventional template-based clustering technique due to the integration capability of the clustering procedure and the parameter estimation. Experimental data show that the HMM-based clustering procedure leads to $1.43\%$ performance improvements over the conventional template-based clustering method and $2.08\%$ improvements over the single HMM method for the case of recognition of the isolated korean digits.

• The Korean Journal of Mycology
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• v.47 no.1
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• pp.13-18
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• 2019

A fungal strain, designated PTT-2, was isolated from the bark of the trunk of a persimmon (Diospyros kaki) tree in Cheongdo, Korea. The isolate showed morphological similarities with Leptosphaerulina saccharicola. Strain PTT-2 had more rapid growth on potato dextrose agar medium than on oatmeal agar, malt extract agar, and synthetic nutrient poor agar media, with colony sizes of 53.8 mm, 49.8 mm, 48.4 mm, and 28.1 mm after 7 days at $25^{\circ}C$ temperature, respectively. Strain PTT-2 produced ascospores, which had irregular wavy edges, oblong to ellipsoidal shape, hyaline appearance and $23.6{\times}10{\mu}m$ size. The black ascomata were developed on PDA medium, and asci were recorded. A BLAST search of the internal transcribed spacer (ITS) region, TEF1-${\alpha}$ and RPB2 gene sequences revealed that strain PTT-2 showed more than 99% nucleotide similarity with a strain of Leptosphaerulina saccharicola previously reported from Thailand. A neighbor-joining phylogenetic tree was constructed by concatenating the above-mentioned sequences, and showed that strain PTT-2 clustered in the same clade with L. saccharicola. Based on these findings, this is the first record of Leptosphaerulina saccharicola occurring in Korea.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2305-2309
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• 2012

Crocin, the main pigment of Crocus sativus L., has been shown to have antiproliferative effects on cancer cells, but the involved mechanisms are only poor understood. This study focused on probable effect of crocin on the immortality of hepatic cancer cells. Cytotoxicity of crocin ($IC_{50}$ 3 mg/ml) in hepatocarcinoma HepG2 cells was determined after 48 h by neutral red uptake assay and MTT test. Immortality was investigated through quantification of relative telomerase activity with a quantitative real-time PCR-based telomerase repeat amplification protocol (qTRAP). Telomerase activity in 0.5 ${\mu}g$ protein extract of HepG2 cells treated with 3 mg/ml crocin was reduced to about 51% as compared to untreated control cells. Two mechanisms of inhibition, i.e. interaction of crocin with telomeric quadruplex sequences and down regulation of hTERT expression, were examined using FRET analysis to measure melting temperature of a synthetic telomeric oligonucleotide in the presence of crocin and quantitative real-time RT-PCR, respectively. No significant changes were observed in the $T_m$ telomeric oligonucleotides, while the relative expression level of the catalytic subunit of telomerase (hTERT) gene showed a 60% decrease as compared to untreated control cells. In conclusion, telomerase activity of HepG2 cells decreases after treatment with crocin, which is probably caused by down-regulation of the expression of the catalytic subunit of the enzyme.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.207-213
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• 2020

Umbrella Arch Method (UAM) often employed in the tunnel construction under poor rock mass conditions in Korea. Insertion of steel pipes at the periphery of the tunnel and infiltration of grouts along the pipes into the rock masses increases tunnel stability. There are two major effects of grouts expected at the tunnel face: 1) increase of face stability by enhancing the frictional resistance of discontinuities and 2) decrease of permeability along the rock masses. Increase of resistance and decrease of permeability requires a certain curing time for the grout. In Korea, we require 24 hours for curing of grout, which means no progress of excavation for 24 hours after infiltration of grouts. This step delays the tunnel construction sequences. To eliminate such inefficiency, we propose MTG (Method for Tunnel construction using Grouting technology), which uses extended length of steel pipes (14 m) compared to conventional pipe roof method (12 m). The merit of MTG is the reduction of curing time. Because of the approximately 2 m extension of the length of steel pipe, blasting can be done after infiltration of grouting. For this paper, we conducted experiments on the shear strength behaviors of grout infilled rock joint with elapsing of curing time and blasting induced vibration. The results show that blasting induced vibration under MTG does not influence the mechanical features of grout material, which indicates no influence on the mechanical behaviors of grout, contributing to the stability of tunnels during excavation. This result indicates that MTG is a cost effective and fast construction method for tunneling in Korea.

• Development and Reproduction
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• v.11 no.3
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• pp.253-261
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• 2007

Lactadherin is a glycoprotein of human milk fat globule membrane that binds to mucin and butyrophilin forming the protein complex. Especially, mucin and lactadherin in human milk efficiently protect infants with poor immune functions right after birth from infections by microorganisms and play important roles for their early survival, growth and development. Lactadherin inhibits the propagation and growth of rotavirus that is a global pathogen causing infants' diarrhea. Recently this protein was known to promote neovascularization and its deficiency related to develop Alzheimer's disease. In this study, the basic biochemical and physiological aspects of lactadherin were investigated. Messenger RNAs were isolated from mammary tissues from Korean women patients to clone a 1.2 kb cDNA and sequenced its DNA to determine its amino acid sequences. The cDNA was cloned to express its 43 kD protein in E. coli, which was confirmed by Western blot. The recombinant protein was purified and injected to 2 rabbits to raise antibodies against it. The semi-purified milk fat globule membrane proteins from Korean women was analyzed by Western blot using the rabbit antibody to give 70, 55, 46, 30 kD bands. Also several polymorphism and SNPs of lactadherin gene from Korean women were observed compared with those of Caucasian women.