• Korean Journal of Materials Research
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• v.19 no.3
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• pp.142-150
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• 2009

In this paper, non-treated ACF (Activated Carbon Fiber) /$TiO_2$ and Zn-treated ACF/$TiO_2$ were prepared. The prepared composites were characterized in terms of their structural crystallinity, elemental identification and photocatalytic activity. XRD patterns of the composites showed that the non-treated ACF/$TiO_2$ composite contained only typical single and clear anatase forms while the Zn-treated ACF/$TiO_2$ contained a mixed anatase and rutile phase with a unique ZnO peak. SEM results show that the titanium complex particles are uniformly distributed on and around the fiber and that the titanium complex particles are more regularly distributed on and around the ACF surfaces upon an increase of the $ZnCl_2$ concentration. These EDX spectra show the presence of peaks from the C, O and Ti elements. Moreover, peaks of the Zn element were observed in the Zn-treated ACF/$TiO_2$ composites. The prominent photocatalytic activity of the Zn-treated ACF/$TiO_2$ can be attributed to the three different effects of photo-degradation: doping, absorptivity by an electron transfer, and adsorptivity of porous ACFs between the Zn-$TiO_2$ and Zn-ACF.

• Journal of Life Science
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• v.19 no.8
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• pp.1125-1131
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• 2009

The antimicrobial activities of Helicobacter pylori as a functional food source with water and 60% ethanol extracts from Rododendron mucronulatum Turcz. flowers were examined. The total phenol content of 60% ethanol extracts (30.6${\pm}$0.14 mg/g) from Rododendron mucronulatum Turcz. flowers was higher than that of water extracts (23.2${\pm}$0.21 mg/g). The inhibitory activities of Rododendron mucronulatum Turcz. extracts on H. pylori was determined to clear zone of 15 mm in 80% ethanol extracts. Purification of inhibitory compounds was carried out in Sephadex LH-20 and MCI-gel CHP-20 column chromatography using a gradient procedure, with increasing ethanol(0${\rightarrow}$100%) in $H_2O$. The chemical structure of the purified inhibitory compounds of H. pylori was identified to be quercitrin (quercetin-3-O- rhamnopyranoside), myricitrin (myricetin-3-O-rhamnopyranoside), quercetin by FAB-MS, NMR and IR spectra.

• Food Science of Animal Resources
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• v.39 no.6
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• pp.966-979
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• 2019

Muscle-based by-products are often undervalued although commonly reported having a high amount of natural bioactive peptides. In this study, elastin was isolated from the protein of broiler hen skin while its hydrolysate was prepared using Elastase. Assessment of antioxidative properties of elastin-based hydrolysate (EBH) was based on three different assays; 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical, 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical and metal chelating ability. The EBH was purified further using ultrafiltration, gel filtration and Reverse- Phase High-Performance Liquid Chromatography (RP-HPLC). The IC₅₀ of ABTS radical activities for EBH were decreased as EBH further purified using ultrafiltration (EBH III; 0.66 mg/mL)>gel filtration (EB-II; 0.42 mg/mL)>RP-HPLC (EB-II4; 0.12 mg/mL). The sequential identification of the peptide was done by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/ TOF-MS) of the potent fractions obtained from RP-HPLC (EB-II4). The presence of hydrophobic amino acids (Val and Pro) in the peptide sequences could potentially contribute to the high antioxidant activity of EBH. The sequences GAHTGPRKPFKPR, GMPGFDVR and ADASVLPK were identified as antioxidant peptides. In conclusion, the antioxidative potential from poultry skin specifically from elastin is evident and can be explored to be used in many applications such as health and pharmaceutical purposes.

• Journal of Powder Materials
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• v.17 no.3
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• pp.203-208
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• 2010

A new High Frequency Induction Heating (HFIH) process has been developed to fabricate dense $Al_2O_3$ reinforced with Fe-Ni magnetic metal dispersion particles. The process is based on the reduction of metal oxide particles immediately prior to sintering. The synthesized $Al_2O_3$/Fe-Ni nanocomposite powders were formed directly from the selective reduction of metal oxide powders, such as NiO and $Fe_2O_3$. Dense $Al_2O_3$/Fe-Ni nanocomposite was fabricated using the HFIH method with an extremely high heating rate of $2000^{\circ}C/min$. Phase identification and microstructure of nanocomposite powders and sintered specimens were determined by X-ray diffraction and SEM and TEM, respectively. Vickers hardness experiment were performed to investigate the mechanical properties of the $Al_2O_3$/Fe-Ni nanocomposite.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.619-630
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• 2005

A two-frame PIV (Particle Image Velocimetry) technique is used to investigate the wake characteristics behind a marine propeller with 4 blades at high Reynolds number. For each of 9 different blade phases from $ 0^{\circ} $ to $ 80^{\circ} $, one hundred and fifty instantaneous velocity fields are measured. They are ensemble averaged to study the spatial evolution of the propeller wake in the region ranging from the trailing edge to one propeller diameter (D) downstream location. The phase-averaged mean velocity shows that the trailing vorticity is related to radial velocity jump, and the viscous wake is affected by boundary layers developed on the blade surfaces and centrifugal force. Both Galilean decomposition method and vortex identification method using swirling strength calculation are very useful for the study of vortex behaviors En the propeller wake legion. The slipstream contraction occurs in the near-wake region up to about X/D : 0.53 downstream. Thereafter, unstable oscillation occurs because of the reduction of interaction between the tip vortex and the wake sheet behind the maximum contraction point.

• Journal of Periodontal and Implant Science
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• v.45 no.1
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• pp.14-22
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• 2015

Purpose: The purpose of this study was to compare serum amyloid A (SAA) protein levels with high-sensitive C-reactive protein (hs-CRP) levels as markers of systemic inflammation in patients with chronic periodontitis. The association of serum titers of antibodies to periodontal microbiota and SAA/hs-CRP levels in periodontitis patients was also studied. Methods: A total of 110 individuals were included in this study. Patients were assessed for levels of hs-CRP and SAA. Nonfasting blood samples were collected from participants at the time of clinical examination. The diagnosis of adipose tissue disorders was made according to previously defined criteria. To determine SAA levels, a sandwich enzyme-linked immunosorbent assay was utilized. Paper points were transferred to a sterile tube to obtain a pool of samples for polymerase chain reaction processing and the identification of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Tannerella forsythia. The serum level of IgG1 and IgG2 antibodies to P. gingivalis, A. actinomycetemcomitans, and T. forsythia was also determined. Results: SAA and hs-CRP levels were higher in periodontitis patients than in controls (P<0.05). In bivariate analysis, high levels of hs-CRP (>3 mg/L) and SAA (>10 mg/L) were significantly associated with chronic periodontitis (P=0.004). The Spearman correlation analysis between acute-phase proteins showed that SAA positively correlated with hs-CRP (r=0.218, P=0.02). In the adjusted model, chronic periodontitis was associated with high levels of SAA (odds ratio [OR], 5.5; 95% confidence interval [CI], 1.6-18.2; P=0.005) and elevated hs-CRP levels (OR, 6.1, 95% CI, 1.6-23.6; P=0.008). Increased levels of serum IgG2 antibodies to P. gingivalis were associated with high levels of SAA (OR, 3.6; 95% CI, 1.4-8.5; P=0.005) and high concentrations of hs-CRP (OR, 4.3; 95% CI, 1.9-9.8; P<0.001). Conclusions: SAA and hs-CRP concentrations in patients with chronic periodontitis are comparably elevated. High serum titers of antibodies to P. gingivalis and the presence of periodontal disease are independently related to high SAA and hs-CRP levels.

• Journal of Gastric Cancer
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• v.17 no.2
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• pp.145-153
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• 2017

Purpose: Identification of the infrapyloric artery (IPA) type is a key component of pylorus-preserving gastrectomy. As the indocyanine green (ICG) fluorescence technique is known to help visualize blood vessels and flow during reconstruction, we speculated that this emerging technique would be helpful in identifying the IPA type. Materials and Methods: From August 2015 to February 2016, 20 patients who underwent robotic or laparoscopic gastrectomy were prospectively enrolled. After intravenous injection of approximately 3 mL of ICG (2.5 mg/mL), a near-infrared fluorescence apparatus was applied. The identified shape of the IPA was confirmed by examining the actual anatomy following infrapyloric dissection. Results: The mean interval time between ICG injection and visualization of the artery was 22.2 seconds (range, 14-30 seconds), and the mean duration of the arterial phase was 16.1 seconds (range, 9-30 seconds). The overall positive predictive value (PPV) of ICG fluorescence in identifying the IPA type was 80% (16/20). The IPA type was incorrectly predicted in four patients, all of whom were obese with a body mass index (BMI) of more than $25kg/m^2$. Conclusions: Our preliminary results indicate that intraoperative vascular imaging using the ICG fluorescence technique may be helpful for robotic or laparoscopic pylorus-preserving gastrectomy.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.3
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• pp.54-61
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• 2003

$SnO_2$ gas sensor for the detection DMMP, simulant of nerve gas was fabricated and its characteristics were examined. Sensing materials were $SnO_2$ added by TEX>$\alpha$-$Al_{2}O_{3}$ with 0∼20wt.% and $In_{2}O_{3}$ with 0∼3wt.% and were physically mixed each material. They were deposited by screen printing method on alumina substrate. The sensor was consisted of sensing electrode with interdigit(IDT) type in front and a heater in back side. Its dimension was 7$\times$10$\times$0.6$\textrm{mm}^2$. Crystallite size 8t phase identification, specific surface area and morphology of fabricated $SnO_2$ powders were analyzed by X-ray diffraction(XRD), surface area analyzer(BET) and by a scanning electron microscope(SEM), respectively. Sensor was measured as flow type and sensor resistance change was monitored as real time using LabVIEW program. The best sensitivities were 75% at adding 4wt.% TEX>$\alpha$-$Al_{2}O_{3}$, operating temperature $300^{\circ}C$ and 87% at adding 2wt.% $In_{2}O_{3}$, operating temperature $350^{\circ}C$ to DMMP 0.5ppm. Response and recovery times were about 1 and 3 min., respectively. Repetition measurement was very good with $\pm$3% in full scale. As a result, operating temperature was lower TEX>$\alpha$-$Al_{2}O_{3}$ than $In_{2}O_{3}$, but sensitivity was higher $In_{2}O_{3}$ than $\alpha$-$Al_{2}O_{3}$.

• Korean Journal of Agricultural Science
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• v.21 no.1
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• pp.60-66
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• 1994

Among the various bacterial isolates from municipal sewages which utilized linear alkylbenzene sulfonate (LAS) as a sole source of carbon. 3 potent strains - KL-3, SH-2 and EN-1 - were selected. The strains were classified: KL-3 as a strain belong to the genus Klebsiella; SH-2 Shigella; and EN-1 Enterobacter, respectively. They were grown in a broth containing 200 ppm of LAS, using a laboratory scale fermentor: the bacterial growth reached stationary phase after 2 days with a maximum viability of $10^8cfu/mL$ of the culture; initial rates of LAS degradation were high during the first 24 hours of cultivation (KL-3 and SH-2, approx. 50%; EN-1, 20%); after 1 day a lag period of about 24 hours was observed for all the strains, and thereafter break-down proceeded rapidly; final rates after 7 days were approximately 85% by KL-3, 82% by SH-2 and 75% by EN-1. Adsorption of LAS by the bacterial cell mass was high for the strain SH-2, as Freundlich equation: Y= 0.030X + 0.95 was calculated.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.973-984
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• 2017

There is a growing need to apply TBM tunnelling method for the construction of underground facilities such as subways and utility tunnels in urban areas. Due to the variability and uncertainty of the ground, tunnelling in urban areas has various safety hazards which could cause damage to people and properties and it is very costly to recover from accidents. Therefore, it is very important to identify hazards from the planning and design phase and to establish risk mitigation measures. In this study, a total of 31 hazards affecting the stability of TBM tunnelling works in urban areas were listed from both the technical literature and correspondence with experts in tunnelling area. The importance and priorities of the hazards were analyzed by conducting Delphi technique, which is a decision-making method by consensus among experts. Finally, 12 hazards that satisfy the content validity criteria were settled and could be used as major control factors for accident prevention during TBM tunnelling works.