• Polymer(Korea)
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• v.33 no.6
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• pp.602-607
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• 2009

A polyurethane (PU) surface enabling in vivo endothelialization via endothelial progenitor cell (EPC) capture was prepared for cardiovascular applications. To introduce CD34 monoclonal antibody (mAb) inducing EPC adhesion onto a surface, poly (poly (ethylene glycol) acrylate-co-butyl methacrylate) and poly (PEGA-co-BMA) were synthesized and then coated on a surface of PU, followed by immobilizing CD34 mAb. $^1H$-NMR analysis demonstrated that poly(PEGA-co-BMA) copolymers with a desired composition were synthesized. Poly(PEGA-co-BMA)-coated PU was much more effective for the immobilization of CD34 mAb, comparing with PEG-grafted PU prepared in our previous study, as demonstrated by that surface density and activity of CD34 mAb increased over 32 times. Physico-chemical properties of modified PU surfaces were characterized by X-ray photoelectron spectroscopy (XPS), water contact angle, and atomic force microscopy (AFM). The results demonstrated that the poly(PEGA-co-BMA) coating was effective for CD34 mAb immobilization and feasible for applying to cardiovascular biomaterials.

• Journal of Dairy Science and Biotechnology
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• v.35 no.4
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• pp.221-231
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• 2017

This study aimed to investigate the physiological characteristics and anti-obesity effects of a newly isolated bacterium, Lactobacillus plantarum K6. L. plantarum K6 showed good ${\alpha}-amylase$ inhibitory activity ($96.78{\pm}3.29%$), ${\alpha}-glucosidase$ inhibitory activity ($92.55{\pm}9.62%$), and lipase inhibitory activity ($85.17{\pm}0.79%$), and the strain inhibited the adipocyte differentiation of 3T3-L1 cells ($27.4{\pm}1.4%$) when present at a concentration of $100{\mu}g/mL$. L. plantarum K6 was isolated from kimchi and its physiological characteristics were investigated. A comparison of the sensitivity of the isolate to 15 different antibiotics showed that L. plantarum K6 is highly sensitive to erythromycin and highly resistant to vancomycin, ampicillin, and polymyxin B. This strain also showed high arylamidase and ${\beta}-galactosidase$ activities. Moreover, it was relatively tolerant to bile acid and low pH, and displayed resistance to Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus, with rates of 51.8%, 42.4%, 61.6%, and 54.9%, respectively. No bio genic amines were produced. L. plantarum K6 also showed high adhesion activity to HT-29 cells compared to L. rhamnosus GG. These results demonstrate that Lactobacillus plantarum K6 has potential as a probiotic with anti-obesity effects.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.295-302
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• 2021

Surface modification of recycled plastic film-based aggregates is demonstrated to enhance the interaction between aggregates and cement paste. It is shown that the oxygen(O₂) atmospheric pressure plasma(APP) treatment leads to a drastic increase in hydrophilicity. In case of the plasma treatment at 100W of RF power, 15/4sccm of O₂/Ar flow rate and 30sec of discharging time, the water contact angle on the aggregates surface decreased from 104.5° to 44.0°. In addition, the contact angle of surface modified aggregates kept in air increased with time elapse. Improvement of hydrophilicity can be explained by the formation of new hydrophilic oxygen functional groups which is identified as C-OH, C-O-C, C=O, -COOH by X-ray photoelectron spectroscopy(XPS) analysis and Fourier-transform infrared spectroscopy(FT-IR). Therefore, it can be concluded that the plasma treatment process is an effective method to improve adhesion of the recycled plastic film-based aggregates and cement paste.

• Journal of the Korean GEO-environmental Society
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• v.25 no.5
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• pp.29-37
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• 2024

This study aimed to investigate the changes in chemical components that occur when weak clay is mixed with steel slag modified with calcium oxide, and to understand the expression characteristics of compressive strength according to hydrophilicity and curing time. XRF testing, SEM imaging, vane shear strength and uniaxial compressive strength testing were conducted. Calcium (Ca) released from the steel slag increases the Ca content in clay by increasing the number of crystal particles and forming a coating layer known as calcium silicate hydrate (CaO-SiO₂-H₂O) through chemical reactions with SiO₂ and Al₂O₃ components. The weak clay stabilized with steel slag is classified into an initial inactive zone where strength relatively does not increase and an activation zone where strength increases over curing time. The vane shear strength of the initial inactive area was found to be 4.4 to 18.4 kN/m² in the state of the weight mixing ratio Rss 30% (steel slag 30% + clay 70%). In the case of the active area, the maximum uniaxial compressive strength increased to 431.8 kN/m² after 480 hours of curing time, which increased due to the apparent adhesion strength of clay through pozzolanic reaction. Therefore, considering the strength expression characteristics of stabilized mixed clay based on the mixing ratio (Rss) during the recycling of steel slag can enhance its practicality in civil engineering sites.

• Journal of the Korean Arthroscopy Society
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• v.10 no.1
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• pp.61-69
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• 2006

Purpose: Open lateral release and complete lateral release have been conducted as a surgical method in patients with patellofemoral malalignment. But authors sought to find out the best method by conducting selective release, with minimal excision of the involved lesion, and comparative analyzing the result, as postoperative satisfaction and complication. Materials and Methods: Over the 68 patients of 90 cases who underwent arthroscopic release, among 94 patients of 129 cases who underwent lateral retinacular release, from January 1993 to June 1998 were followed up prospectively. A radiological evaluation of patellar inclination, patellar tilt, congruence angle, and Q-angle and a clinical evaluation of HSS-Knee score and modified patellar score were used for analysis data before operation and data at 1 year and 5 year after operation. Results: According to the radiologic evaluation, the patellar tilt and translation revealed improvement of the results, from $13.4^{\circ}$ and 12.1mm to $3.6^{\circ}$ and 3.8mm with arthroscopic lateral complete release, and from $12.3^{\circ}$ and 11.2mm to $4.8^{\circ}$ and 5.2mm with selective release, and from $13.6^{\circ}$ and 12.3mm to $3.3^{\circ}$ and 3mm with open release. But they were not significantly related to the clinical results. HSS-Knee score was 84.2%(48/57), 81.8%(27/33), 82.1%(32/39) and modified patellar score was 82.5%(47/57), 81.8%(27/33), 82.1%(32/39) respectively, which revealed satisfactory results. And no significant difference among the operative methods were shown. Conclusion: Arthroscopic lateral retinacular release which is one of the surgical method for patellofemoral malalignment enhances rehabilitation and satisfaction of the patient, by releasing the involved retinaculum within lesser surgical extent, compared to open and complete lateral release without complications such as adhesion.

• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.36-44
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• 1998

Background: IFN-$\gamma$ is known to activate mononuclear phagocytes and to mediate host defense mechanism against some intracellular microorganisms, but little is known about anti-mycobacterial activity and mechanism of IFN-$\gamma$ in human. In this study, we investigated the role of IFN-$\gamma$ in the pathogenesis of tuberculosis by observing the effect of IFN-$\gamma$ on the phagocytosis of M.tuberculosis(MTB) and on the production of TNF-$\alpha$ by human pulmonary alveolar macrophage. Method: Pulmonary alveolar macrophage(PAM) were prepared with adhesion purification method from bronchoalveolar lavage fluid obtained from 8 persorn without active lung lesion and cultured($1{\times}10^6cells/ml$) with MTB($3{\times}10^7$ bacteria/ml) with or without IFN-$\gamma$(300U/ml), LPS(0.5ug/ml) and autologous serum(10%). After 2 hours, the percentage of PAM-phagocytosed MTB was counted after AFB staining(modified Kynion method). TNF-$\alpha$ production by PAM stimulated by IFN-$\gamma$(300U/ml), MTB($1{\times}10^6bacteria/ml$) and LPS(0.5ug/ml) for 24hours was measured in culture supernatant using ELISA method. The degree of phagocytosis of MTB by PAM stimulated with IFN-$\gamma$(300U/ml) and LPS(0.5ug/ml) for 24hours was also investigated. Results: IFN-$\gamma$ did not influence the phagocytosis of MTB by PAM(percentage of PAM-phagocytosed MTB: control: $22.1{\pm}4.9$, IFN-$\gamma$: $20.3{\pm}5.3$) and did not increase TNF-$\alpha$ production by PAM (control: $21{\pm}38pg/ml$, IFN-$\gamma$: $87{\pm}106pg/ml$), and the degree of phagocytosis of MTB by PAM pre-stimulated with IFN-$\gamma$ for 24 hours, was not increased (control: $24.5{\pm}9.5$, IFN-$\gamma$: $23.4{\pm}10.1$). Conclusion: IFN-$\gamma$ does not influence on the phagocytosis of MTB and TNF-$\alpha$ production by PAM.

• Clean Technology
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• v.20 no.3
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• pp.232-240
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• 2014

The significance of thermoplastic polyolefin polypropylene (PP) lies in its potential to replace polyvinyl chloride (PVC), the most widely used material for automobile interiors (door trim, dash board), which discharges harmful compounds in certain conditions. Another benefit of PP (0.855 amorphous - 0.946 crystalline $g/cm^3$) is its low density compared to that of PVC ($1.1-1.45g/cm^3$), which reduces vehicle weight. Market demand for eco-friendly water-based adhesive/coating material is rising significantly as a substitute for solvent-based adhesive/coating material which emits VOC and causes harmful working conditions. Under such context, in this study, a series of eco-friendly waterborne polyurethane-urea primer (a paint product that allows finishing paint to adhere much better than if it were used alone) for hydrophobic PP were prepared from different mix of DMPA content, NCO/OH molar ratio, various wt% of silicone diol and various soft segment content, among which DMPA of 21 mole %, NCO/OH molar ratio of 1.2, modified silicone diol of 5 wt% and soft segment content of 73 wt% led to good adhesion strength. Additionally, the incorporation of optimum content of additives (0.5 wt% dispersing agent, 0.5 wt% levelling agent, 1.5 wt% antifoaming agent, 3.0 wt% matting agent) into the optimum waterborne polyurethane-urea also enabled good stability, levelling, antifoaming and non-glossy.