• 제목/요약/키워드: Biological mechanism

검색결과 1,496건 처리시간 0.022초

저온에서 생물활성탄의 기질제거특성 (Substrate Removal Characteristics for Low Temperature by Biological Activated Carbon)

  • 류성호;박중현
    • 상하수도학회지
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    • 제11권2호
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    • pp.76-93
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    • 1997
  • Activated carbon is widely used for the treatment of water, wastewater and other liquid wastes. Biological activated carbon (BAC) process is water and wastewater treatment process developed in the 1970's. In addition to activated carbon adsorption, biodegradation organic pollutants occurs in the BAC bed where a large amount of aerobic biomass grows. This results in a long operation time of the carbon before having to be regenerated and thus a low treatment cost. Although the BAC process has been widely used, its mechanisms have not been well understood, especially the relationship between biodegradation and carbon adsorption, whether these two reactions can promote each other or whether they just simultaneously exist in the BAC bed. Also, the phenomenon of bioregeneration has been confused that previously occupied adsorption sites appear to be made available through the actions of microorganisms. And that, because biological process is influenced by low temperature, the mechanism of the BAC process is also effected by temperature variation in our country of winter temperature near the freezing point. Therefore, the objective of this study examines closely the mechanism of the BAC process by temperature variation using phenol as substrate. From this study, biological activated carbon is good substrate removal better than non adsorbing materials (charcoal, sand) as temperature variation, especially low temperature(near $5^{\circ}C$).

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Homomorphic Deconvolution 법에 의한 초음파 감쇄정수 추정 (Estimation of Ultrasound Attenuation Coefficient by Homomorphic Deconvolution Method)

  • 홍승홍;허웅
    • 대한의용생체공학회:의공학회지
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    • 제5권1호
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    • pp.39-46
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    • 1984
  • In order to improve the performance of ultrasonic diagnostic equipment, it is important to development the signal processing considering the ultrasonic properties of biological medium and propagation mechanism in tissue. Attenuation coefficient is not only important factor to analyze propagation properties, but also it is significant to estimate it in view of tissue characterization, so we show one of the method to estimate attenuation coefficient of biological tissue and the results of estimation.

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고려인삼의 생리.생화학적 효과연구 (Studies on the Physiological and Biochemical Effects of Korean Ginseng)

  • 정노팔;진승하
    • Journal of Ginseng Research
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    • 제20권4호
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    • pp.431-471
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    • 1996
  • Korean ginseng has been thought and used the most very important medicinal herb among the oriental medicinal drugs for thounds of years Korean ginseng had many ingredients such as tripenoid saponins. Nitrogen compounds, polysaccharides, polyacetylenic compounds and lipid compounds. Korean ginseng has wide effects in the various systems of human such as nervous system. Vascular system. Digestive system. endocrine system, immune system. etc. Many researchess who were interested in the biological effects of Korean ginseng have concerned the tripenoid saponins among the components of ginseng and carried out to find the effects of ginseng using the various experimental system. From their results, it was unveiled many effects of Korean ginseng gractually in the experimental systems and shown that Korean ginseng has various effects in the biological system. But recent studies has been carried out to the difference ginseng components, besides ginseng saponin thought to have various effects in biological systems. Also the functional mechanism of ginseng in the biological system is limited but the basic research to elucidate the mysterious effects of ginseng has been preferred. In this review, we focus on biological effects of Korean ginseng. Especially physiological and biochemical aspects in biological systems.

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Azasugar-Containing Phosphorothioate Oligonucleotide (AZPSON) DBM-2198 Inhibits Human Immunodeficiency Virus Type 1 (HIV-1) Replication by Blocking HIV-1 gp120 without Affecting the V3 Region

  • Lee, Jinjoo;Byeon, Se Eun;Jung, Ju Yeol;Kang, Myeong-Ho;Park, Yu-Jin;Jung, Kyeong-Eun;Bae, Yong-Soo
    • Molecules and Cells
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    • 제38권2호
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    • pp.122-129
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    • 2015
  • DBM-2198, a six-membered azasugar nucleotide (6-AZN)-containing phosphorothioate (P = S) oligonucleotide (AZPSON), was described in our previous publication [Lee et al. (2005)] with regard to its antiviral activity against a broad spectrum of HIV-1 variants. This report describes the mechanisms underlying the anti-HIV-1 properties of DBM-2198. The LTR-mediated reporter assay indicated that the anti-HIV-1 activity of DBM-2198 is attributed to an extracellular mode of action rather than intracellular sequence-specific antisense activity. Nevertheless, the antiviral properties of DBM-2198 and other AZPSONs were highly restricted to HIV-1. Unlike other P = S oligonucleotides, DBM-2198 caused no host cell activation upon administration to cultures. HIV-1 that was pre-incubated with DBM-2198 did not show any infectivity towards host cells whereas host cells pre-incubated with DBM-2198 remained susceptible to HIV-1 infection, suggesting that DBM-2198 acts on the virus particle rather than cell surface molecules in the inhibition of HIV-1 infection. Competition assays for binding to HIV-1 envelope protein with anti-gp120 and anti-V3 antibodies revealed that DBM-2198 acts on the viral attachment site of HIV-1 gp120, but not on the V3 region. This report provides a better understanding of the antiviral mechanism of DBM-2198 and may contribute to the development of a potential therapeutic drug against a broad spectrum of HIV-1 variants.

Color-Tuning Mechanism of the Lit Form of Orange Carotenoid Protein

  • Man-Hyuk Han;Hee Wook Yang;Jungmin Yoon;Yvette Villafani;Ji-Young Song;Cheol Ho Pan;Keunwan Park;Youngmoon Cho;Ji-Joon Song;Seung Joong Kim;Youn-Il Park;Jiyong Park
    • Molecules and Cells
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    • 제46권8호
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    • pp.513-525
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    • 2023
  • Orange carotenoid protein (OCP) of photosynthetic cyanobacteria binds to ketocarotenoids noncovalently and absorbs excess light to protect the host organism from light-induced oxidative damage. Herein, we found that mutating valine 40 in the α3 helix of Gloeocapsa sp. PCC 7513 (GlOCP1) resulted in blue- or red-shifts of 6-20 nm in the absorption maxima of the lit forms. We analyzed the origins of absorption maxima shifts by integrating X-ray crystallography, homology modeling, molecular dynamics simulations, and hybrid quantum mechanics/molecular mechanics calculations. Our analysis suggested that the single residue mutations alter the polar environment surrounding the bound canthaxanthin, thereby modulating the degree of charge transfer in the photoexcited state of the chromophore. Our integrated investigations reveal the mechanism of color adaptation specific to OCPs and suggest a design principle for color-specific photoswitches.