• Korean Journal of Food Science and Technology
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• v.46 no.2
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• pp.262-267
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• 2014

To analyze the presence of microbes in organic farm produce, green chillies, lettuce, tomatoes, apples, pears, and rice were collected at 47 production sites with organic and conventional produce. Total average bacterial counts of 4.07 log CFU/g in organic green chillies, 3.71 log CFU/g in conventional green chillies, and 6.76- 6.90 log CFU/g in the both lettuce were detected. Mean bacterial counts of 4.48 log CFU/g and 2.84 log CFU/g were detected in organic and conventional pear produce, respectively. Differences in bacterial counts in tomatoes, apples, and rice in organic and conventional produce were less pronounced. Clostridium perfringens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus were not detected in any produce sample. However, Bacillus cereus was detected with average counts of 1.04 log CFU/g in 11/47 (23%) conventional produce samples and 1.97 log CFU/g in 6/47 (13%) organic produce samples. Therefore, organic and conventional produce showed similar microbial prevalence patterns, and comparable safety in terms of pathogen contamination.

• Journal of the Korean Magnetics Society
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• v.11 no.6
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• pp.239-244
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• 2001

Recently, RF inductor having researched by many workers, we fabricated and investigated properties of RF inductors. In order to improve the Q-factor (Quality), we try to apply the patterned Fe$_{78.81}$Ta$_{8.47}$N$_{12.71}$ soft magnetic thin film of 5000 which shows magnetic anisotropy of 30 Oe. Thus, patterned magnetic film was artificially increased magnetic anisotropy lead to increasing of ferro-magnetic resonance frequency up to GHz band. Coil as part of inductor was fabricated by lift off process. The dimension of RF inductor was designed 47un, rectangular shape, and measured properties. In the case of Ti/Ag air core type inductor shows Q of 9, inductance of 8.4 nH at 2 GHz. Magnetic film employed inductor shows inductance of 9 nH and FMR resonance frequency was 700 MHz.

• Korean Journal of Veterinary Research
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• v.36 no.2
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• pp.379-387
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• 1996

The objects of the present study were to establish the method of purification, subunit dissociation of verotoxin-2 (VT2) produced by Escherichia coli O157:H7, and to investigate the characteristics of purified verotoxin-2 such as molecular weight and composition of amino acid. The results were summerized as follows; Verotoxin-2 was extracted by addition of polymyxin B sulfate into bacterial cell lysate prepared from Escherichia coli O157:H7(KSC109). As an initial step, the bacterial cell lysate was precipitated with 30% saturated ammonium sulfate. The precipitated crude toxin was then subjected to anion-exchange, chromatofocusing and cation-exchange chromatography. Using this scheme, we obtained highly purified toxin with a specific activity of $1.1{\times}10^9$ $CD_{50}/mg$. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) for purified VT2 showed two protein bands. The upper band, approximately 32 Kd, was supposed as A subunit and the lower band, approximately 7.7 Kd, was supposed as B subunit. When the toxin was separated in the subunit-dissociating solution, two peaks emerged with retention times of 15 and 28 min by HPLC. These peaks represented A subunit and B subunit, respectively. The amino acid composition of purified VT2 were made up in order of glutamic acid, histamine, asparaginic acid, histidine, lysine, alanine and leucine etc. The largest amount among the amino acid composing VT2 was methionine.

• Journal of Microbiology
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• v.40 no.1
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• pp.77-81
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• 2002

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a pleiotropic hematspoietic growth factor involved in the development of myeloid cells from bone marrow, and an activator of mature myeloid cells functioning in a variety of antimicrobial and inflammatory responses. Recently, recombinant GM-CSF is increasingly under clinical study for treatment of various diseases including cancer, infectious diseases and hematopoietic diseases as well as for an immune response modulator, In this study, we constructed a recombinant human GM-CSF (rhGM-CSF) expression plasmid with a pelB leader sequence and His. Tag under T7 promoter control. The expression construct was shown to produce a recombinant protein of 20 kDa in the 8M urea preparation, indicating the rhGM-CSF may be expressed as an insoluble inclusion form. The 20 kDa recombinant protein in 8M urea was transformed into the water-so1ub1e form by dialysis against PBS buffer (phosphate buffered saline). The soluble rhGM-CSF protein was shown to stimulate colony formation and cell proliferation in vitro, indicating that the rhGM-CSF could be refolded into its native form to show colony stimulating activity.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.775-788
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• 2010

The decomposition of 2,4,6-trinitrotoluene (TNT) and the mass balance of nitrogen (N) species as products were investigated in a UV/H2O2system by varying pH, concentrations of $H_2O_2$, and $O_2$. All experiments were conducted in a semi-batch system employing a 50 mL reaction vessel and a coil-type quartz-tube reactor. In contrast with previous studies employing batch mode, TNT decomposition in the semi-batch mode was proportionally enhanced by increasing $H_2O_2$ concentration to 10 mM (0.034%), indicatingthat an inhibitory effect of excess $H_2O_2$on hydroxyl radical (${\cdot}OH$) can be negligible. N compounds are released as $NO_2^-$ in the early stages of the reaction, but $NO_2^-$ is rapidly oxidized to $NO_3^-$ by means of ${\cdot}OH$. $NH_4^+$ was also detected in this study and showed gradually the increase with increasing reaction time. In this study, $NH_4^+$ production can involve the reduction of nitro group of TNT concurrent with the production of $NO_3^-$. Of the N species originating from TNT decomposition, 12 ~ 72% were inorganic forms (i.e. [$NO_3^-$] + [$NO_2^-$] + [$NH_4^+$]). This result suggests that the large remaining N portions indicate that unidentified N compounds can exist.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.91-98
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• 2013

The degradation of durability and increase of fatigue on the ship are mainly caused by vibration of the engine and rotating machineries. The damper to minimize the influence from vibration is usually attached between the machineries and its base. General damper applied on the vessel is passive damper which is designed to attenuate specified frequency signals, i.e, high frequency vibration signals. But it is hard to anticipate its performance for low frequency signals. In this research, active vibration isolator using VCM is developed to suppress wide band vibration signals. Routh-Huritz's stable condition, ultimate sensitivity method and parameter tuning are applied to derive PID parameters and 2 and 4 phase choppers are also adapted to drive VCM. Simulation and experiments are executed to confirm the effectiveness of the proposed control schemes.

• Journal of the Korean Society for Nondestructive Testing
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• v.16 no.1
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• pp.29-33
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• 1996

The eddy current test(ECT) probe of differential encircling coil type was designed and fabricated, and the optimum condition of ECT was derived for the examination of the irradiated fuel rod. The correlation between ECT test frequency and phase & amplitude was derived by performing the test of the standard rig that includes inner notches, outer notches and through-holes. The defect of through-hole was predicted by ECT at the G33-N2 fuel rod irradiated in the Kori-1 nuclear power reactor. The metallographic examination on the G33-N2 fuel rod was Performed at the defect location predicted by ECT. The result of metallographic examination for the G33-N2 fuel rod was in good agreement with that of ECT. This proves that the evaluation for integrity of irradiated fuel rod by ECT is reliable.

• Journal of Korean Neurosurgical Society
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• v.38 no.4
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• pp.269-272
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• 2005

Objective : The object of this study is to present the treatment experience of the 6cases of scalp arteriovenous malformations[AVMs] focus on treatment strategy. Methods : Six patients with scalp AVM were treated during past 12years. We analysis the clinical characteristics of the lesions, treatment methods and management outcomes. Results : The lesions were located on temporal in 2patients, parietal in 2patients, frontal and occipital area in each one. Four of six patients had a trauma history on scalp. The presenting symptoms were progressive enlarged pulsating mass with or without bruit. Four of the six lesions had the large fistula in the lesion. Two patients were treated with surgical resection alone, three patients with proximal feeding artery balloon[s] occlusion followed by surgical resection, and one patient with coil embolization through trans-venous route alone. We obtained good results in all patients. Conclusion : Most of scalp AVM can be completely cured by Judicious selection and a combination of treatment modalities, i.e., surgery only, or embolization only, or embolization plus surgical therapy. Although embolization became a primary therapy for this sort of scalp AVM recently, the selection of treatment modality should be chose based on the size, angioarchitecture, and clinical presentations of the lesion.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.405-413
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• 2004

The rheological properties of an exopolysaccharide, EPS-R, produced by the marine bacterium Hahella chejuensis strain 96CJ 10356 were investigated. The $E_{24}$ of $0.5\%$ EPS-R was $89.2\%$, which was higher than that observed in commercial polysaccharides such as xanthan gum ($67.8\%$), gellan gum ($2.01\%$) or sodium alginate ($1.02\%$). Glucose and galactose are the main Sugars in EPS-R, with a molar ratio of ${\~}1:6.8$, xylose and ribose are minor sugar components. The average molecular mass, as determined by gel filtration chromatography, was $2.2{\times}10^3$ KDa, The intrinsic viscosities of EPS-R were calculated to be 16.5 and 15.9 dL/g using the Huggins and Kraemer equations, respectively, with a 2.3 dL/g overlap. In terms of rigidity, the conformation of EPS-R was similar to that of caboxymethyl cellulose ($5.0{\times}10^{-2}$). The rheological behavior of EPS-R dispersion indicated that the formation of a structure intermediate between that of a random-coil polysaccharide and a weak gel. The aqueous dispersion of EPS-R at concentrations ranging from 0.25 to $1.0\%$ (w/w) showed a marked shear-thinning property in accordance with Power-law behavior. In aqueous dispersions of $1.0\%$ EPS-R, the consistency index (K) and flow behavior index (n) were 1,410 and 0.73, respectively. EPS-R was Stable to pH and salts.

• BMB Reports
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• v.38 no.5
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• pp.624-631
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• 2005

Tuberculosis, caused by Mycobacterium tuberculosis, continues to be one of the main diseases to mankind. It is urgent to discover novel drug targets for appropriate antimicrobial agents against this human pathogen. The shikimate pathway is onsidered as an attractive target for the discovery of novel antibiotics for its essentiality in bacteria and absence in mammalian cells. The Mycobacterium tuberculosis aroE-encoded shikimate dehydrogenase was cloned, expressed and purified. Sequence alignment analysis shows that shikimate dehydrogenase of Mycobacterium tuberculosis exhibit the pattern of G-X-(N/S)-V-(T/S)-X-PX-K, which is highly conserved within the shikimate dehydrogenase family. The recombinant shikimate dehydrogenase spectrum determined by CD spectroscopy showed that the percentages for $\alpha$-helix, $\beta$-sheet, $\beta$-turn, and random coil were 29.2%, 9.3%, 32.7%, and 28.8%, respectively. The enzymatic characterization demonstrates that it appears to be fully active at pH from 9.0 to 12, and temperature $63^{\circ}C$. The apparent Michaelis constant for shikimic acid and $NADP^+$ were calculated to be about $29.5\;{\mu}M$ and $63\;{\mu}M$. The recombinant shikimate dehydrogenase catalyzes the substrate in the presence of $NADP^+$ with an enzyme turnover number of $399\;s^{-1}$. Zymological studies suggest that the cloned shikimate dehydrogenase from M. tuberculosis has a pretty activity, and the work should help in the discovery of enzyme inhibitors and further of possible antimicrobial agents against Mycobacterium tuberculosis.