• Title, Summary, Keyword: synergistic effect

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Soot Formation Characteristics of Concentric Diffusion Flames with Mixture Fuels (이중동축류 화염을 이용한 혼합연료의 매연생성 특성에 관한 연구)

  • Lee, Won-Nam
    • 한국연소학회:학술대회논문집
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    • pp.123-128
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    • 2002
  • The synergistic effect of ethylene/propane and ethylene/methane mixtures on soot formation is studied experimentally with a concentric co-flow burner. The integrated soot volume fractions, laser light scattering signal and PAH concentrations are measured for different fuel supply configurations. The synergistic effect in ethylene/propane diffusion flames is found to be affected not only by the composition of mixture but also by the way of mixing. Comparing to the homogeneously mixed ethylene/propane case, the increase of soot formation is observed when propane is supplied through the inner nozzle, while the decrease is observed when propane is supplied through the outer nozzle. However, the measured PAH concentration distributions are inconsistent with the current view of the synergistic effect of ethylene./propane mixture on soot formation. Virtually no synergistic effect is observed in ethylene-methane flames regardless of the fuel supply configuration, which suggests the important role of $C_3$ species produced during the propane pyrolysis process for the synergistic effect.

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Synergistic Effect of Molybdate and Monoethanolamine on Corrosion Inhibition of Ductile Cast Iron in Tap Water

  • Kim, K.T.;Chang, H.Y.;Lim, B.T.;Park, H.B.;Kim, Y.S.
    • Corrosion Science and Technology
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    • v.16 no.1
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    • pp.31-37
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    • 2017
  • A synergistic effect was observed in the combination of nitrite and ethanolamines. Ethanolamine is one of the representative organic corrosion inhibitors and can be categorized as adsorption type. However, nitrosamines can form when amines mix with sodium nitrite. Since nitrosamine is a carcinogen, the co-addition of nitrite and ethanolamine will be not practical, and thus, a non-toxic combination of inhibitors shall be needed. In order to maximize the effect of monoethanolamine, we focused on the addition of molybdate. Molybdate has been used to alternate the addition of chromate, but it showed insufficient oxidizing power relative to corrosion inhibitors. This work evaluated the synergistic effect of the co-addition of molybdate and monoethanolamine, and its corrosion mechanism was elucidated. A high concentration of molybdate or monoethanolamine was needed to inhibit the corrosion of ductile cast iron in tap water, but in the case of the co-addition of molybdate and monoethanolamine, a synergistic effect was observed. This synergistic effect could be attributed to the molybdate that partly oxidizes the metallic surface and the monoethanolamine that is simultaneously adsorbed on the graphite surface. This adsorbed layer then acts as the barrier layer that mitigates galvanic corrosion between the graphite and the matrix.

Synergistic Killing Effect of Synthetic Peptide P20 and Cefotaxime on Methicillin-Resistant Nosocomial Isolates of Staphylococcus aureus

  • Jung, Hyun-Jun;Choi, Kyu-Sik;Lee, Dong-Gun
    • Journal of Microbiology and Biotechnology
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    • v.15 no.5
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    • pp.1039-1046
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    • 2005
  • The salt resistance of antibacterial activity and synergistic effect with clinically used antibiotic agents are critical factors in developing effective peptide antibiotic drugs. For this reason, we investigated the resistance of antibacterial activity to antagonism induced by NaCl and $MgCl_2$ and the synergistic effect of P20 with cefotaxime. P20 is a 20-residue synthetic peptide derived from a cecropin A (CA)-melittin(ME) hybrid peptide. In this study, P20 was found to have potent antibacterial activity against clinically isolated methicillin-resistant Staphylococcus aureus (MRSA) strains without hemolytic activity against human erythrocytes. The combination study revealed that P20 in combination with cefotaxime showed synergistic antibacterial activity in an energy-dependent manner. We also confirmed the synergism between P20 and cefotaxime by fluorescence-activated flow cytometric analysis by staining bacterial cells with propidium iodide (PI) and bis-(1,3-dibutylbarbituric acid) trimethine oxonol (BOX). This study suggests that P20 may be useful as a therapeutic antibiotic peptide with synergistic effect in combination with conventional antibiotic agents.

Synergistic effect of lysozyme on bactericidal activity of magnolol and honokiol against a cariogenic bacterium, streptococcus mutans OMZ 176

  • Bae, Ki-Hwan;Oh, Hong-Rock
    • Archives of Pharmacal Research
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    • v.13 no.1
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    • pp.117-119
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    • 1990
  • A combination of magnolol or honokiol with lysozyme isolated from the egg white of the Korean Ogol fowl (Korean natural monument No.265) exhibited synergistic effect of bactericidal activity against a typical cariogenic bacterium, Streptococcus mutans OMZ 176. The synergistic ratio increased with time dependence.

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Synergistic Interactions Between Chitinase ChiCW and Fungicides Against Plant Fungal Pathogens

  • Huang, Chien-Jui;Chen, Chao-Ying
    • Journal of Microbiology and Biotechnology
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    • v.18 no.4
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    • pp.784-787
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    • 2008
  • Antifungal activity of ChiCW and synergistic interactions between ChiCW with fungicides were investigated. Conidial germinations of phytopathogenic fungi, Alternaria brassicicola, Botrytis elliptica, and Colletotrichum gloeosporioides, were inhibited by ChiCW but A. longipes was not. In addition, ChiCW showed synergistic effect with fungicides Switch (cyprodinil+fludioxonil) and tebuconazole to inhibit fungal conidial germinations. The level of synergism of ChiCW with tebuconazole was higher than that with Switch. The results indicate that ChiCW may exhibit a higher level of synergism with fungicides that have a primary effect upon membranes.

Synergistic Effect of Cisplatin and Berberine on Inhibition of Cell Growth and Induction of Apoptosis involving Oxidative Stress in HeLa Cells (자궁경부암 세포주에서 활성산소종의 영향애 의한 Apoptosis를 통하여 세포성장을 억제하는 Cisplatin과 Berberine의 상승효과)

  • Cho, Hae-Joong
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.21 no.4
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    • pp.992-997
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    • 2007
  • Cisplatin is a chemotherapeutic drug which is widely used for cancer therapy including cervical cancer. The purpose of this study is to elucidate synergistic effect of Cisplatin and Berberine on the apoptosis of HeLa cells and to determine whether oxidants are formed as part of apoptotic process. Apoptotic death of HeLa cells by cisplatin and berberine was confirmed by chromatin condensation of HeLa cells and flow cytometric analysis of intracellular ROS(reactive oxygen species) production. In MTT assay, Cell viability was decreased and enhanced ROS generation in combination of cisplatin and berberine significantly, as compared with cisplatin only. Synergistic effect of Cisplatin and Berberine on the inhibition of cell growth by apoptosis was clearly observed and ROS may play an important role in apoptosis. This effect suggest the possibility lowering the concentration of chemotherapeutic drugs, which alleviate the side effect of drugs.

Antitumor Effect and the Change of Chemosensitivity of Chitosan in Human Lung Cancer Cell Line (인체 폐암세포주에 대한 키토산의 항암효과와 항암제 감수성에 미치는 영향)

  • 노숙령
    • Journal of Nutrition and Health
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    • v.31 no.4
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    • pp.739-746
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    • 1998
  • This study was designed to investigated the antitumor effect and change chemosensitivity of chitosan in 2 kinds of humen lung cancer cell lines(NCI-H522, NCI-H596). To evaluate the antitumor effect and synergistic effectof chomosensitivity, MTT assay was used in vitro. then anticancer drugs used were 챤-platin , ectoposide, and adrimycin. The results of this study were as follows; Chitosan shwoed in antitumor effect on both NCI-H522 and NCI-H596. The lung cancer viability percent for NCI-H522 and NCL-H596 showed at the lowest levels of 5.31 and 5.33% when the concentration of chitosan was 25mg/$m\ell$ media and the exposure time of chitosan was 72 hours. ID50 value of chitosan on both NCI-H522 and NCI-H596 showed at the lowest levels of 14.07, 11.68 mg/$m\ell$ media when the exposure time of chitosan was 72 hours. the synergistic effect of chomosensitivity was better in NCI-H596 than in NCI0H522 . When the synergistic effect of chomosensitivity was shown according to the kind of the anticancer drugs, in case of NCI-H522 , in the concentration of 100$\mu\textrm{g}$/$m\ell$, ectoposide showed the highest synergistic effect of chomosensitivity and then was adrimycin In case of NCI-H596, in the concentration of 100$\mu\textrm{g}$/$m\ell$,, the order of the synergistic effect of chomosensitivity was ectoposide>adrimycin>cis-platin and in the concentration of 10$\mu\textrm{g}$/$m\ell$, ectoposide>cis-platin >adrimycin. It is concluded that chitosan is an active antitumor agent and is increased chomosensitivity though there is difference according to the kind and the concentration of anticancer drugs. But to be sued to lung cancer theraphy, further studies on toxicity, the mechanism of action, animal experiment are wanted.

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Synergistic Effect of Lipopolysaccharide and Interferon-$\beta$ on the Expression of Chemokine Mig mRNA

  • Lee, Moon-Sook;Kim, Sung-Kwang;Kim, Hee-Sun
    • Journal of Microbiology and Biotechnology
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    • v.12 no.5
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    • pp.813-818
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    • 2002
  • Expression of monokine induced by IFN-$\gamma$(Mig) mRNA is well-known to strictly depend on Interferon-$\gamma$(IFN-$\gamma$). Lipopolysaccharide (LPS) alone Is weakly effective on Mig mRNA expression in mouse Peritoneal macrophages. This study was undertaken to investigate the synergistic effect of LPS and IFN-$\beta$ on chemokine Mig gene expression in mouse peritoneal macrophages. Although IFN-$\beta$ alone was minimally effective, LPS plus IFN-$\beta$ synergized to produce a high level of Mig mRNh. The synergistic effect of LPS and IFN-$\beta$ (LPS/IFN-$\beta$) on Mig mRNA expression was strain-specific. The most effective synergistic effect of LPS/IFN-$\beta$ on the mRNh expression was found in simultaneous stimulation of LPS/IFN-$\beta$. This synergy was modulated at the level of the gene transcription and was not dependent on a new protein synthesis. Synergistic effect of LPS/IFN-$\beta$ also required the activation of $NF-_KB$. Accordingly, these data suggest that LPS/IFN-$\beta$ synergizes the expression of Mig mRNA through a process that depends on a pretranscriptional level and/or coincident Mig mRNA transcription.

Antibacterial Effect of Amentoflavone and Its Synergistic Effect with Antibiotics

  • Hwang, Ji Hong;Choi, Hyemin;Woo, Eun-Rhan;Lee, Dong Gun
    • Journal of Microbiology and Biotechnology
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    • v.23 no.7
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    • pp.953-958
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    • 2013
  • Selaginella tamariscina is a traditional herb used in medicine. Phytochemical amentoflavone, a biflavonoid class of flavonoids, was isolated from the plant of Selaginella tamariscina. In this study, the antibacterial effects and combination effects of amentoflavone and conventional antibiotics such as ampicillin, cefotaxime, and chloramphenicol were investigated. These results showed that amentoflavone had a considerable antibacterial effect and synergistic interaction with antibiotics against various bacterial strains (fractional inhibitory concentration index ${\leq}$ 0.5), except for Streptococcus mutans. To study the mechanism(s) involved in the synergistic activities between amentoflavone and antibiotics, we detected hydroxyl radical formation using 3'-(p-hydroxyphenyl) fluorescein and measured the $NAD^+/NADH$ ratio by $NAD^+$ cycling assay. The results indicated that the formation of hydroxyl radical would be a cause of the synergistic effect and that this oxidative stress originated from a transient NADH depletion. This study suggests that amentoflavone synergizes with antibiotics and has potential as a therapeutic agent for antimicrobial chemotherapy.

The Synergistic Effect of Organophosphorus and Dithiocarbamate Ligands on Metal Extraction in Supercritical CO2

  • Koh, Moon-Sung;Park, Kwang-Heon;Yang, Doo-Hyun;Kim, Hak-Won;Kim, Hong-Doo
    • Bulletin of the Korean Chemical Society
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    • v.26 no.3
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    • pp.423-427
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    • 2005
  • The bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex-272) and sodium diethyl- dithiocarbamate (NaDDC) ligands were used to extract of metal ions ($Cd^{2+},\;Co^{2+},\;Cu^{2+},\;Pb^{2+},\;Zn^{2+}$) in supercritical $CO_2$. Experiments showed a strong synergistic effect and better extraction efficiency if the two ligands were used together. In-situ UV-visible observation indicates that NaDDC in the water/supercritical $CO_2$ started to decompose slowly. The synergistic effect seems to come from the deprotonation of the organophosphorus ligand by amines from the decomposed NaDDC. The enhancing role of amines was confirmed using the mixture of Cyanex-272 and diethylamine(DEA) in the metal extraction.