• Title/Summary/Keyword: Chemical potential

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Toxicity of Nanomaterials and Strategy of Risk Assessment (나노물질의 독성과 위해성평가 전략)

  • Park, Kwang-Sik
    • Environmental Analysis Health and Toxicology
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    • v.20 no.4 s.51
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    • pp.259-271
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    • 2005
  • Engineered nanoparticles exhibit a variety of unique and tunable chemical and physical properties. These unique properties make the nanoparticles central components and widespread potential applications in nanoindustry. However, the potential toxicities of nanoparticles have not been fully evaluated. Recently, the impacts of nanoparticles to human and environment became the emerging issue of toxicology. In this article, physicochemical properties and toxicities of carbon nanotube, fullerene, quantum dots, and other types of nanomaterials were reviewed and the strategy of risk assessment were suggested based on the frame of chemical assessment.

A Regiospecific One-Pot, Three Component Synthesis of 4-Aryl-6,8-dimethylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-diones as New Potential Monoamine Oxidase Inhibitors

  • Khalafy, Jabbar;Rimaz, Mehdi;Panahi, Leila;Rabiei, Hossein
    • Bulletin of the Korean Chemical Society
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    • v.32 no.7
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    • pp.2428-2432
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    • 2011
  • A series of new 4-aryl-6,8-dimethylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-diones have been synthesized via three component reaction of 1,3-dimethylbarbituric acid with arylglyoxals in the presence of hydrazinium dihydrochloride in ethanol. All of these derivatives may act as potential monoamine oxidase inhibitors.

표면특성 변화에 따른 유류분해 미생물의 토양내 거동성 조절

  • 류두현;목지예;최상일;김용미;이경애
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.360-362
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    • 2003
  • The adhesion of hydrocarbon degrading bacteria(HDB) differing in surface hydrophobicity was investigated. Cell wall hydrophobicity was modified chemically and physiologically. Modified adhesion deficient mutant of HDB was selected in a soil column assay Physiologically and chemical modification increased cell surface hydrophobicity. Cell surface charcteristis including BATH and zeta potential were measured. Physiological modification using ampicillin was not stable, but chemical modification was stabel. Hydrocarbon degrading potential was measured for modified and unmodifed HDB.

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Theoretical Investigation of Edge-modified Zigzag Graphene Nanoribbons by Scandium Metal with Pyridine-like Defects: A Potential Hydrogen Storage Material

  • Mananghaya, Michael
    • Bulletin of the Korean Chemical Society
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    • v.35 no.1
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    • pp.253-256
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    • 2014
  • Functionalization of zigzag graphene nanoribbon (ZGNR) segment containing 120 C atoms with pyridine (3NV-ZGNR) defects was investigated on the basis of density-functional theory (DFT) calculations, results show that edge-modified ZGNRs by Sc can adsorb multiple hydrogen molecules in a quasi-molecular fashion, thereby can be a potential candidate for hydrogen storage. The stability of Sc functionalization is dictated by a strong binding energy, suggesting a reduction of clustering of metal atoms over the metal-decorated ZGNR.

Does the Gaseous Aniline Cation Isomerize to Methylpyridine Cations Before Dissociation?

  • Choe, Joong Chul
    • Bulletin of the Korean Chemical Society
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    • v.34 no.11
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    • pp.3249-3252
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    • 2013
  • We have explored the potential energy surface for the isomerization of the aniline (AN) radical cation to the 2-, 3-, and 4-methylpyridine (picoline, MP) radical cations using G3 model calculations. The isomerization may occur through the 1H-azepine (7-aza-cycloheptatriene) radical cation. A quantitative kinetic analysis has been performed using the Rice-Ramsperger-Kassel-Marcus theory, based on the potential energy surface. The result shows that isomerization between $AN^{+\bullet}$ and each $MP^{+\bullet}$ hardly occurs before their dissociations.

Design and Synthesis of Quipazine Based Re-Complexes for the Development of Potential SPECT Imaging Agents with 99m Tc for 5-HT Transporter

  • In, Mi-Young;Chi, Dae-Yoon;Choi, Sun-Ju;Park, Kyung-Bae;Cho, Cheon Gyu
    • Bulletin of the Korean Chemical Society
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    • v.23 no.10
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    • pp.1439-1444
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    • 2002
  • 6-Nitroquipazine has higher binding affinity for SERT than other selective serotonin reuptake inhibitors. We have prepared 6-nitroquipazine based rhenium complexes which would lead to the development of potential SPECT imaging agents with $^{99m}Tc$ for 5-HT transporter.

Pharmacophore Modelling, Quantitative Structure Activity Relationship (QSAR) and Docking Studies of Pyrimidine Analogs as Potential Calcium Channel Blockers

  • Choudhari, Prafulla B.;Bhatia, Manish S.;Jadhav, Swapnil D.
    • Journal of the Korean Chemical Society
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    • v.57 no.1
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    • pp.99-103
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    • 2013
  • The present communication deals with the Pharmacophore modeling, 3D QSAR and docking analysis on series of Pyrimidine derivatives as potential calcium channel blockers. The computational studies showed hydrogen bond donor, hydrogen bond acceptor, and hydrophobic group are important features for calcium channel blocking activity. These studies showed that Pyrimidine scaffold can be utilized for designing of novel calcium channels blockers for CVS disorders.

The Determination of Interconversion Barrers of Oxygen-Containing Cyclohexene Analogues

  • Ju, Jae Beom;Lee, Su No;Lee, Guk Haeng
    • Bulletin of the Korean Chemical Society
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    • v.17 no.1
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    • pp.7-11
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    • 1996
  • The interconversion barriers between two twisted conformers of four oxygen-containing cyclohexene analogues have been investigated utilizing a periodic hindered pseudorotational model, molecular mechanics (MM3) calculations, and previously reported far-infrared spectra. The six-fold pseudorotational potential energy function satisfactorily fits the observed bending transitions. The interconversion barrier heights calculated from the pseudorotational model show excellent agreement with those determined from two-dimensional potential energy surfaces for the ring-bending and ring-twisting vibrations. The barriers to interconversion range from 3350 $cm^{-1}$ (9.6 kcal/mol) to 3890 $cm^{-1}$ (11.1 kcal/mol) for four oxygen-containing cyclohexene analogues.

Study on Corrosion Inhibition from Aspect of Quantum Chemistry

  • Fouda, A.S.;Abu-Elnader, H.M.;Soliman, M.S.
    • Bulletin of the Korean Chemical Society
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    • v.7 no.2
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    • pp.97-99
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    • 1986
  • Calculated ionization potential, electron affinity, electron density and bond order of some thiophene derivatives have been obtained and correlated with the inhibition of corrosion produced by these substances as evaluated by polarization curves. It is apparent that such quantities as the electron density or ionization potential play an important role. The calculation was carried out by the Extended Huckel method for the series of substituted thiophene derivatives.