• Journal of Life Science
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• v.12 no.1
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• pp.77-86
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• 2002

Chitin, a $\beta$-1,4 polymer of N-acetyl-D-glucosamine, is one of the most abundant organic compounds in nature. Chitinase (EC 3.2.1.14) is an enzyme that degrades chitin to chito-oligosaccharides, diacetyl rhitobiose and N-acetyl-D-glucosamine. An extracellular chitinase-producing bacterial strain was isolated from soil and named to as Bacillus subtilis JK-56. Optimum culture condition of B. subtilis JK-56 for the production of chitinase was 1% chitin, 0.5% polypepton, 0.1% KCl, 0.05% MnS $O_4$.4$H_2O$, 37$^{\circ}C$, initial pH 7.0 and 40 hour culture time. When B. subtilis JK-56 was grown in the optimum medium, one major active band and two minor active bands were detected by native-PAGE and active staining of the gel. Among them, the major band was purified from the culture supernatant by 70% ammonium sulfate precipitation and native-PAGE with BIO-RAD Model 491 Prep-Cell and named as Chi-56A. Its molecular weight was estimated to be 53kDa monomer and the isoelectric point (pI) was pH 4.3. The pH and temperature for the optimum activity of Chi-56A were pH 6.0 and $65^{\circ}C$, respectively. Chi-56A was stable up to $65^{\circ}C$ and in alkaline region. Its $K_{m}$ value for colloidal chitin was 17.33g/L. HPLC analysis of the reaction products confirmed that Chi-56A was an exo type chitinase.e.

• Proceedings of the Korea Port Economic Association Conference
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• 2006.08a
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• pp.1-12
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• 2006

As national economies globalize, demand for intercontinental container shipping services is growing rapidly, providing a potential economic boon for the countries and communities that provide port services. On the promise of profits, many governments are investing heavily in port infrastructure, leading to a possible glut in port capacity, driving down prices for port services and eliminating profits as ports compete for business. Further, existing ports are making strategic investments to protect their market share, increasing the chance new ports will be overcapitalized and unprofitable. Governments and port researchers need a tool for understanding how local competition in their region will affect demand for port services at their location, and thus better assess the profitability of a prospective port. We propose to develop such a tool by extending our existing simulation model of global container traffic to incorporate demand-side shipper preferences and supply-side strategic responses by incumbent ports to changes in the global port network, including building new ports, scaling up existing ports, and unexpected port closures. We will estimate shipper preferences over routes, port attributes and port services based on US and international shipping data, and redesign the simulation model to maximize the shipper's revealed preference functions rather than simply minimize costs. As demand shifts, competing ports will adjust their pricing (short term) and infrastructure (long term) to remain competitive or defend market share, a reaction we will capture with a game theoretic model of local monopoly that will predict changes in port characteristics. The model's hypotheses will be tested in a controlled laboratory experiment tailored to local port competition in Asia, which will also serve to demonstrate the subtle game theoretic concepts of imperfect competition to a policy and industry audience. We will apply the simulation model to analyze changes in global container traffic in three scenarios: addition of a new large port in the US, extended closure of an existing large port in the US, and cooperative and competitive port infrastructure development among Korean partner countries in Asia.

• Clinical and Experimental Reproductive Medicine
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• v.32 no.3
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• pp.279-286
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• 2005

Objective: Although several genetic factors have been associated with defects in human spermatogenesis, the unambiguous causative genes have not been elucidated. The male infertility by haploinsufficiency of PRM1 or PRM2 has been reported in mouse model. The aim of this study was to identify the single nucleotide polymorphisms (SNPs) of PRM1 and PRM2, related to the genotype of Korean infertile men. Methods: Genomic DNAs were extracted from peripheral bloods of infertile men with oligozoospermia or azoospermia, and analyzed using polymerase chain reaction (PCR) and direct sequencing. We carried out the direct sequencing analysis of amplified fragments in PRM1 (557 nucleotides from -42 to 515) and PRM2 (599 nucleotides from 49 to 648) genes, respectively. Results: Three SNPs of coding region in the PRM1 gene was found in the analysis of 130 infertile men. However, the SNPs at a133g (aa 96.9%, ag 3.1% and gg 0.0%), c160a (cc 99.2%, ca 0.8% and aa 0.0%) and c321a (cc 56.9%, ca 35.4% and aa 7.7%) coded the same amino acids, in terms of silence phenotypes. On the other hand, as results of the PRM2 gene sequencing in 164 infertile men, only two SNPs, g398c (gg 62.2%, gc 31.1% and ga 6.7%) and a473c (aa 63.4%, ac 29.9% and cc 6.7%), were identified in the intron of the PRM2 gene. Conclusions: There was no mutation and significant SNPs on PRM1 and PRM2 gene in Korean infertile men. These results suggest that the PRM1 and PRM2 genes are highly conserved and essential for normal fertility of men.

• Journal of Breast Cancer
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• v.21 no.4
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• pp.371-381
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• 2018

Purpose: Immune suppression is common in patients with advanced breast cancer but the mechanisms underlying this phenomenon have not been sufficiently studied. In this study, we aimed to identify B7 family members that were able to predict the immune status of patients, and which may serve as potential targets for the treatment of breast cancer. We also aimed to identify microRNAs that may regulate the expression of B7 family members. Methods: The Cancer Genome Atlas data from 1,092 patients with breast cancer, including gene expression, microRNA expression and survival data, were used for statistical and survival analyses. Polymerase chain reaction and Western blot were used to measure messenger RNA and protein expression, respectively. Luciferase assay was used to investigate direct microRNA target. Results: Bioinformatic analysis predicted that microRNA (miR)-93, miR-195, miR-497, and miR-340 are potential regulators of the immune evasion of breast cancer cells, and that they exert this function by targeting CD274, PDCD1LG2, and NCR3LG1. We chose CD274 for further investigations. We found that miR-195, miR-497, and CD274 expression levels were inversely correlated in MDA-MB-231 cells, and miR-195 and miR-497 expressions mimic inhibited CD274 expression in vitro. Mechanistic investigations demonstrated that miR-195 and miR-497 directly target CD274 3' untranslated region. Conclusion: Our data indicated that the level of B7 family members can predict the prognosis of breast cancer patients, and miR-195/miR-497 regulate CD274 expression in triple negative breast cancer. This regulation may further influence tumor progression and the immune tolerance mechanism in breast cancer and may be able to predict the effect of immunotherapy on patients.

• Food Engineering Progress
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• v.15 no.4
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• pp.370-375
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• 2011

In this study the polymerase chain reaction (PCR) combined with denaturing gradient gel electrophoresis (DGGE) was evaluated as a method permitting the rapid detection of pathogens in fresh originally grown vegetables. A universal primer (341GCf/534r) was selected for its ability to amplify the V3 region of 16S-rRNA genes in their target pathogens (Salmonella typhimurium, Pseudomonas fluorescens, Bacillus cereus, Listeria monoytogenes, Staphyloocus aureus, E. coli). The 194 bp fragments in PCR were successfully duplicated as expected. The amplified fragments of the same size from six different pathogens also showed good separation upon DGGE. The detection limit of PCR-DGGE for six pathogens in fresh-cut lettuces were over $10^{5}$ CFU/g when sampled by stomaching. However, when the sampling method was changed from stomaching to shaking, the detection limit of six pathogens in organic vegetables was shown to increase by over $10^{1}$ CFU/g, but only those of B. cereus were over $10^{3}$ CFU/g. Therefore, PCR-DGGE was shown to be a reliable method for the detection of pathogens in fresh-cut vegetables.

• Journal of the Korea Convergence Society
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• v.9 no.12
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• pp.401-409
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• 2018

The purpose of this study was to examine the oral health care and self-rated health status of adults visiting dental clinics in the region of Busan and influential factors for their dental fear from January to May, 2017, in an effort to obtain some information on how to relieve fear. As for dental fear, adults who were in their 30s, who were homemakers and whose monthly income ranged from 4 to 4.99 million won. In regard to fear according to oral health care, dental fear caused by the treatment avoidance factor was stronger among the adults who didn't receive dental checkups and who brushed their teeth in the wrong way. Dental fear that was attributed to the physiological reaction factor and the stimuli-inducing factor was severer among the adults who didn't receive dental checkups and who had no scaling experience. Overall fear was severer among the adults who didn't receive dental checkups and who changed their toothbrushes every four or more months. The factors that affected dental fear were self-rated health status, self-rated oral health status, gender, age, whether to receive dental checkups on a regular basis or not, and oral health education experience. Therefore in order to alleviate dental fear, self-rated health status should be improved, and the kind of system that encourages regular dental checkups and provides oral health education should be prepared.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.5 no.1
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• pp.18-25
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• 2019

2-Nitroimidazole derivatives have been reported to accumulate in hypoxic tissue. We prepared a novel $^{99m}Tc-MAG_3$-2-nitroimidazole and evaluated the feasibility for hypoxia imaging agent. $Bz-MAG_3$-2-nitroimidazole was synthesized by direct coupling of $Bz-MAG_3$ and 2-nitroimidazole using dicyclohexylcarbodiimide. $Bz-MAG_3$-2-nitroimidazole was labeled with $^{99m}Tc$ in the presence of tartaric acid and $SnCl_2-2H_2O$ at $100^{\circ}C$ for 30 min. And the reaction mixture was purified by $C_{18}$ Sep-pak cartridge. The labeling efficiency and the radiochemical purity were checked by ITLC-SG/acetonitrile. The tumor was grown in balb/c mice for 8~13 days after the subcutaneous injection of tumor cells, CT-26 (murine colon adenocarcinoma cell). Biodistribution study and tumor autoradiography were performed in the xenografted mice after i.v injection of 74 kBq/0.1 mL and 19 MBq/0.1 mL of $^{99m}Tc-MAG_3$-2-nitroimidazole, respectively. In vivo images of $^{99m}Tc-MAG_3$-2-nitroimidazole in tumor bearing mice were obtained 1.5 hr post injection. The labeling efficiency was $45{\pm}20%$ and the radiochemical purity after purification was over 95%. Paper electrophoresis confirmed negative charge of $^{99m}Tc-MAG_3$-2-nitroimidazole. $^{99m}Tc-MAG_3$-2-nitroimidazole was very stable at room temperature and its protein binding was 53%. The $^{99m}Tc-MAG_3$-2-nitroimidazole exhibited high uptake in the liver, stomach and intestine. In biodistribution study using tumor bearing mice, the uptakes (% ID/g) of the tumor were $0.5{\pm}0.1$, $0.4{\pm}0.0$, $0.2{\pm}0.1$ and $0.1{\pm}0.1$ at 5, 15, 30 min and 4 hrs. Tumor/muscle ratio were $1.4{\pm}0.1$, $2.2{\pm}0.83$, $3.0{\pm}0.9$, and 3.7 (n=2) for 5, 15, 30 min and 4 hrs. The uptake in hypoxic area was found higher than in non-hypoxic area of tumor tissue by autoradiography. In vivo images showed the relatively faint uptake to the hypoxic tumor region. $^{99m}Tc-MAG_3$-2-nitroimidazole was successfully synthesized and found feasible for imaging hypoxia.

• Korean Journal of Heritage: History & Science
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• v.44 no.3
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• pp.4-17
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• 2011

The Baekje's cotton fabrics were excavated from 'Neungsan-ri temple site in Buyeo' (September 1999-April 2000) and stored at Buyeo National Museum after conservation treatment. In this study, it carred out non-destructive, chemical and morphological analysis for fiber identification, also considered on influx, features and difference between the 'Baek-cheop-po(Three kingdom period's cotton fiber)' and 'Mok-myeon(imported by Munikjeom, late Korea dynasty)'. As a result, the fiber proved cellulose fiber through analytical researches like color reaction, FT-IR(chemical analysis). It was also confirmed lumens, typical dimensional structure(morphological analysis) as an features of cotton fiber. The fiber was the first evidence in ancient Korea's cotton. But it can not prove that whether weaving were made in Baekje's area. However there were documentation that people in Beakje make cloth to silk fabric from 'Mahan period'. We can suppose that they have had an old weaving techniques. This study has a great historical, academic values as the only evidence for the hypothesis of a weaving technique of the Baekje's cotton. Through comparison to each region's ancient cottons, we can investigate the species of Baekje's cotton and ancient Korea cotton's influx.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.302-310
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• 2019

Precise and fast identification of crop cultivars is essential for efficient breeding and plant breeders' rights. Traditional methods for identification of jujube cultivars are based on the evaluation of morphological characteristics. However, due to time constraints and environmental influences, it is difficult to distinguish cultivars using only morphological traits. In this study, we cloned fragments from improved inter simple sequence repeats (ISSR) analysis, and developed stably diagnostic sequence-characterized amplified region (SCAR) markers. The specific ISSR bands of jujube cultivars from Dalizao and Boeundaechu were purified, cloned, and sequenced. As a result, four clones labeled 827Dalizao550, 827Boeun750, 846Boeun700, and 847Dalizao850 were identified. In order to investigate whether they were specific for the jujube cultivar, four pairs of SCAR primers were then designed and polymerase chain reaction (PCR) amplifications were conducted to analyze 32 samples, including jujube and sour jujube. In the PCR amplification of the 827Dalizao550 SCAR marker, the specific bands with 550 bp were amplified in six samples (Dalizao, Sandonglizao, Dongzao, Yuanlin No. 2, Suanzao 2, Suanzao 4), but unexpected bands (490 bp) were amplified in the others. Moreover, in the PCR amplification of the 847Dalizao850 SCAR marker, the specific bands with 850 bp were found in three samples (Dalizao, Sandonglizao, and Dongzao) and 900 bp unexpected bands were amplified in five samples (Pozao, Suanzao 1, Suanzao 2, Suanzao 3, Suanzao 4). These results showed that newly developed markers could be useful as a fast and reliable tool to identify jujube cultivars. However, further identification of polymorphic information and the development of SCAR markers are required for the identification of more diverse cultivars.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.376-383
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• 2011

The CMCs of LA and LA3 nonionic surfactants obtained from the reaction between glycidol and lauryl alcohol were found to be $0.97{\times}10^{-3}mol/L$ and $1.02{\times}10^{-3}mol/L$ respectively and the surface tensions for 1 wt% surfactant were 26.99 and 27.48 mN/m respectively. Dynamic surface tension measurements using a maximum bubble pressure tensiometer showed that the adsorption rate of surfactant molecules at the interface between the air and the surfactant solution was found to be relatively fast in both surfactant systems, presumably due to the high mobility of surfactant molecules. The contact angles of LA and LA3 nonionic surfactants were 27.8 and $20.9^{\circ}$ respectively and the dynamic interfacial tension measurement by a spinning drop tensiometer showed that interfacial tensions at equilibrium condition in both systems were almost the same. Also both surfactant systems reached equilibrium in 2~3 min. Both surfactant solutions showed high stability when evaluated by conductometric method and the LA nonionic surfactant system provided the higher foam stability than the LA3 nonionic surfactant system. The phase behavior experiments showed a lower phase or oil in water (O/W) microemulsion in equilibrium with an excess oil phase at all temperatures studied. No three-phase region was observed including a middle-phase microemulsion or a lamellar liquid crystalline phase.