• Polymer(Korea)
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• v.33 no.4
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• pp.358-363
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• 2009

Maleic anhydride-grafted polypropylene has been widely used to improve the interfacial interaction between the components in PP/polar polymer blends and PP/filler composites and to maximize the physical properties and thermal properties. In this paper. the maleic anhydride (MAH)-grafted polypropylene (co-PP) was fabricated through reactive extrusion process with di-cumyl peroxide (DCP) as an initiator. The grafting degree of MAH depending on the contents of DCP and MAH was investigated by FT-IR spectra and chemical titration. The grafting degree increased with increasing MAH concentration and also showed maximum value at 0.06 wt% of DCP concentration. Melt flow index (MFI) of the grafted copolymer was increased with increasing the contents of MAH. The DSC and TGA analysis data indicate the melting temperature and thermal degradation of PP depending on the grafting degree of MAH.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.116-120
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• 2005

In this study, composites with polypropylene(PP) and Jute fiber were prepared by compression molding technique. Generally, hydrophilic jute fibers do not adhere well to PP, which is hydrophobic. Maleic anhydride grafted polypropylene(MAPP) had been widely used as a coupling agent to improve the bonding between ligno-cellulosic fibers and PP. The coupling agent improved the tensile and flexural properties when the mechanical properties were tested by using a UTM. The mechanical properties of natural fiber composites(NFCs) by modified thermoplastics were higher than those of NFCs by unmodified thermoplastics. Fracture surfaces of the composites and the fiber orientations were investigated by scanning electron microscopy. The mechanical performance of NFCs by modified thermoplastics appeared to be improved by the enhanced interface adhesion between the fiber and the matrix.

• International Journal of Advanced Culture Technology
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• v.11 no.2
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• pp.323-329
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• 2023

In this study, Proline pentamer model was used to investigate change in the dihedral angle, intramolecular hydrogen bonding and formation energies during structural optimization. L-Proline (LP, as an imino acid residue) pentamers having four conformation types [β: φ/ψ=t−/t+, α: φ/ψ=g−/g−, PP_II: φ/ψ=g−/t+ and Plike: φ/ψ= g−/g+] were carried out by QCC [B3LYP/6-31G(d,p)]. The optimized structure and formation energy were examined for designated structure. In LP, P-like and PP_II types did not change by optimization, and β types were transformed into PP_II having no H-bond independently of the designated ψ values. PP_II was more stable than P-like by about 2.2 kcal/mol/mu. The hydrogen bond distances of d2(4-6) type H-bonds were 1.94 - 2.00Å. In order to understand the processes of the transformations, the changes of φ/ψ, distances of NH-OC (d_NH/CO) and formation energies (ΔE, kcal/mol/mu) were examined.

• Journal of Life Science
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• v.21 no.7
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• pp.1046-1051
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• 2011

Diallyl disulfide (DADS), the most prevalent oil-soluble organosulfur compound in garlic, is known to have diverse biological activities, including anticarcinogenic, antiatherosclerotic, antiinflammatory, and antioxidant actions. In this study, we investigated the effect of DADS on the expression of heme oxygenase-1 (HO-1) in human liver hepatoma cell line HepG2. Treatment of HepG2 cells by DADS evoked a dose-dependent growth inhibition without significant toxicity to the cells, and also induced the expression of transcription factor Nrf2. However, DADS did not have any enhancing effect on transcription and translation of HO-1 expression in HepG2 cells. In addition, DADS efficiently blocked protein synthesis of HO-1 in HepG2 cells stimulated by CoPP or hemin. But, DADS did not decrease the content of transcripts of HO-1 gene stimulated by CoPP, with accumulation of Nrf2 and small Maf in the nucleus. Based on these results, we conclude that DADS inhibits HO-1 expression by modulation of translational level of CoPP or hemin-induced HO-1 expression in HepG2 cells.

• Polymer(Korea)
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• v.30 no.1
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• pp.80-84
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• 2006

2-Biphenylyl acrylate(BPA) was synthesized by the reaction of acryloyl chloride with 2-phenylphenol (2PP). Hydrophilic copolymers with the moiety of the microbicide, 2PP, were prepared by the radical copolymerization of BPA and methacrylic acid (MA). From the compositions of the BPA unit and the MA unit in the copolymers, the monomer reactivity ratios were determined to be 0.86 for BPA and 1.21 for MA by means of Kelen-Tudos plot. This result indicates that the copolymers have a random structure. The amount of 2PP released through the hydrolysis of the copolymers was examined by UV spectrometry. The result showed that the release of 2PP increased with an increase in the hydrophilic MA content in the copolymers and with an increase in the pH of the release medium. Therefore, these results indicate that the hydrophilic polymers bearing 2-phenylphenol moiety can be controlled release microbicides.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.11-19
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• 2015

The important properties of EVA (ethylene vinyl acetate) redispersible polymer was waterproof, densification of internal pore space of concrete and ball bearing and micro filler. Also, the significant role of polypropylene(PP) fiber was crack control and blockade of movement for deterioration factors. The most studies for EVA were limited in the field of mortar and PP fiber reinforced concrete had been studied in the state of being restricted unit water content, rich mix and mixing much of the fiber without considering construction site. Therefore, the control mix design were applied in ready mixed concrete using 10 % fly ash of total cement weight used in batch plant. On the basis of control mix design, EVA contents ranging from 0 % to 10 % of total cement weight and PP fiber contents ranging from 0 % to 0.5 % of EVA concrete volume were used in the mix designs. The results showed the maximum compressive strength value was measured at EVA 5.0 % and PP fiber 0.1 %, the minimum water absorption ratio was at EVA 10 % and PP fiber 0 %, the durability factor for freezing and thawing resistance was at EVA 5.0 % and PP fiber 0.3 % and the minimum weight reduction ratio of resistance to sulfuric acid attack was at EVA 10 % and PP fiber 0.5 % after curing age 42days. Meanwhile, From these results, PP fiber reinforced EVA concrete would be very benefit, if each optimal mix types were used in hydraulic structures, underground utilities and agricultural structures.

• Journal of the Korean Chemical Society
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• v.36 no.5
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• pp.685-691
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• 1992

The $d^8$-transition metal complexes containing diphosphine, $MCl_2PP$ were prepared by using $K_nMCl_m$ as starting materials, wherein M were Ni(II), Pd(II), Pt(II) and Au(III) and PP were bis(diphenylphosphino)methane(dppm), bis(diphenylphosphino)ethane(dppe), bis(diphenylphosphino)propane (dppp) and bis(diphenylphosphino)ethylene(dppety). The complexes were characterized by the spectral property $(^H-NMR$, $^{31}P-NMR$ and UV-Visible spectra) together with elemental analysis. The complexes were tested for the catalytic activity on the formation reactions of 3(2H)-furanone and cyclic carbonate. The only Ni(II)- and Pd(II)-diphosphine complexes displayed a good catalytic effects in the production of 3(2H)-furanone from 2-methyl-3-butyn-2-ol [reaction (1)]. But all the diphosphine complexes as catalyst were almost inactive towards cyclic carbonate production preaction [reaction (2)].

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.32 no.2
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• pp.1-10
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• 2019

Objectives : The objective of present study is to evaluate anti-inflammatory and anti-allergic effects of Perilla(Perilla frutescens; Labiatae, PF), the roots of Peucedanum praeruptorum(PP) and the root of Scutellaria baicalensis(SB) in vitro and anti-asthmatic effects of mixture of PF, PP and SB(PS) on ovalbumin (OVA)-induced asthma in BALB/c mice. Methods : Anti-inflammatory and anti-allergic effects were observed on the lipopolysaccharide(LPS) treated RAW 264.7 cells through Nitric Oxide(NO) production and RBL-2H3 cells through ${\beta}$-hexosaminidase. Anti-asthmatic effects were observed on the number of inflammatory cells in bronchoalveolar lavage fluid(BALF) and the level of IgE in serum on OVA-induced BALB/c mice. Results : The treatment of PF, PP and SB(12.5, 25, 50, $100{\mu}g/m{\ell}$) resulted in a significant inhibition of NO production in RAW 264.7 cells and mast cell degranulation in RBL-2H3 cells. Oral administration of PS(400mg/kg/day) resulted in a significant reduction in the numbers of eosinophils in BALF and level of IgE in serum. Conclusion : The oral administration of PS is effective in ameliorating the eosinophilic infiltration in vivo and thus can be a good therapeutic candidate for allergic asthma.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.229-240
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• 2010

Most of all researchs and analyses in the field of television industry of Korea were related to Cable Television SO(System Operator), but few about PP(Program Provider) from the viewpoint of Industrial Theory in Korea. However, there wasn't a comprehensive research analysis in terms of the co-relationship of the market structure, market conduct and market performance of PP. This research analyzes co-relationship and dynamics of the market structure of PP, its market conduct and market performance in a comprehensive way in Cable TV industry. Especially this paper focuses on the analysis of 1)relationship and its influence between market structure and market conduct, 2) relationship and its influence between their market conducts and market performances and 3) relationship and its influence between market structure and market performance among 40 commercial PPs in terms of the theory of Industrial Organization in Korea. This paper is delated and reported as follows in conclusion : 1)the type of horizontal integration has an effect on the price and scale in the relationship between the structure and its conduct. 2)the price has effect on the revenue and viewing rate between the conduct and performance. And high dependency of the Cable TV license fee has an effect on viewing rate and revenue per subscribers(ARPU) between the conduct and performance. 3)The horizontal integration between the structure and performance had a positive effect on viewing rate and its product differentiation has an effect on the revenue per subscribers. Net cost of the product had a negative effect on the rate of profit.

• YAKHAK HOEJI
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• v.45 no.1
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• pp.78-84
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• 2001

Heme oxygenase is a rate-limiting enzyme in heme catabolism that cleaves heme to form biliverdin, iron, and carbon monoxide. Heme oxygenase-1 is expressed in many types of cells and tissues and is highly induced in response to oxidative stress. Carbon monoxide, one of the products of heme oxygenase, can stimulate soluble guanylate cyclase and dilate the vascular smooth muscle. So, the induction of heme oxygenase by lipopolysaccharide (LPS)-induced oxydative stress and the effect of the resultant carbon monoxide on aortic contractility were examined in this study. Zinc protoporphyrine IX (ZnPP), a inhibitor of heme oxygenase, elicited weak contraction of thoracic aortic ring, and this effect was more potent in aorta of LPS-treated rats than control and was blocked by methylene blue. The hyperreactivity to ZnPP in LPS-treated group was blocked by co-treatment with aminoguanidine. In the aortic ring of LPS-treated rats, ZnPP didn't change the vasoreactivity to phenylephrine or acetylcholine. ZnPP elicited hyper-tensive effect in concious rats, and pretreatment with LPS did not affect this effect. Prazosin significantly diminished the hypertensive effect of ZnPP. These results indicate that LPS induced heme oxygenase in aotra, and the resultant carbon monoxide diminished the aortic reactivity to vasoconstrictor.