ChemInform Abstract: Microporous Crystal 12CaO×7Al2O3 Encaging Abundant O‐ Radicals.

Hayashi, Katsuro; Hirano, Masahiro; Matsuishi, Satoru; Hosono, Hideo

doi:10.1002/chin.200222239

Cited by 13 publications

(13 citation statements)

References 1 publication

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“…4a) shows an orthorhombic signal characteristic of O 2 -trapped on the Ca 2? cations in the g 2 side-on fashion within the nanocavities [45,46]. Its analysis via computer simulation allowed extraction of the g tensor components (g zz = 2.078, g yy = 2.012, and g xx = 2.005), which are in a nice accordance with predictions of the Känzig-Cohen …”

Section: Principal Mechanisms Of O 2 2 Formation and Varieties Of Supsupporting

confidence: 56%

Diagnostic Features of EPR Spectra of Superoxide Intermediates on Catalytic Surfaces and Molecular Interpretation of Their g and A Tensors

et al. 2015

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The use of electron paramagnetic resonance spectroscopy to study the superoxide intermediates, generated by end-on and side-on adsorption of the naturally abundant and 17 O-enriched dioxygen on catalytic surfaces is discussed. Basic mechanisms of O 2 -radical formation via a cationic redox mechanism, an anionic redox mechanism, and an electroprotic mechanism are illustrated with selected oxide-based systems of catalytic relevance. Representative experimental spectra of various complexities are analyzed and their diagnostic features have been identified and interpreted. The molecular nature of the g and A tensors of the electrostatic and covalent superoxide adducts is discussed in detail within the classic and density functional theory based approaches.

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Section: Principal Mechanisms Of O 2 2 Formation and Varieties Of Supsupporting

confidence: 56%

Diagnostic Features of EPR Spectra of Superoxide Intermediates on Catalytic Surfaces and Molecular Interpretation of Their g and A Tensors

et al. 2015

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“…[10] Various anions (F -, Cl -, OH -, O -, and O À 2 ) can replace O 2-ions in the cage. [11][12][13][14] Recent results indicate that a part of the O 2-ions in the cage can be removed under reducing conditions (carbon container) at high temperatures producing a nonstoichiometric oxide with high electronic conductivity. [15] The X-ray diffraction pattern of Ca 12 Al 14 O 33 exposed to reducing conditions was almost identical to that of the sample heated in dry oxygen.…”

Section: Introductionmentioning

confidence: 99%

Phase Equilibria in the System Al2O3-CaO-CoO and Gibbs Energy of Formation of Ca3CoAl4O10

Jacob

Shekhar

Kale

2008

J. Phase Equilib. Diffus.

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An isothermal section of the system Al 2 O 3 -CaO-CoO at 1500 K has been established by equilibrating 22 samples of different compositions at high temperature and phase identification by optical and scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy after quenching to room temperature. Only one quaternary oxide, Ca 3 CoAl 4 O 10 , was identified inside the ternary triangle. Based on the phase relations, a solid-state electrochemical cell was designed to measure the Gibbs energy of formation of Ca 3 CoAl 4 O 10 in the temperature range from 1150 to 1500 K. Calcia-stabilized zirconia was used as the solid electrolyte and a mixture of Co + CoO as the reference electrode. The cell can be represented as: ð-ÞPt; CaAl 2 O 4 + Ca 12 Al 14 O 33 + Ca 3 CoAl 4 O 10 + Co//(CaO)ZrO 2 //CoO + Co; Pt ð + Þ: From the emf of the cell, the standard Gibbs energy change for the Ca 3 CoAl 4 O 10 formation reaction, CoO + 3/5CaAl 2 O 4 + 1/5Ca 12 Al 14 O 33 fi Ca 3 CoAl 4 O 10 , is obtained as a function of temperature: DG o r /J mol 21 (±50) = 22673 + 0.289 (T/K). The standard Gibbs energy of formation of Ca 3 CoAl 4 O 10 from its component binary oxides, Al 2 O 3 , CaO, and CoO is derived as a function of temperature. The standard entropy and enthalpy of formation of Ca 3 CoAl 4 O 10 at 298.15 K are evaluated. Chemical potential diagrams for the system Al 2 O 3 -CaO-CoO at 1500 K are presented based on the results of this study and auxiliary information from the literature.

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“…In addition, results from flow-cytometry reported by Hewitt et al (2001) supported this theory. Although the mechanism of active oxygen species generation from alkaline earth metal oxides, such as CaO, was not explored, Hayashi et al (2002) recently reported that a solid solution of CaO and alumina could generate a large amount of active oxygen species using ESR measurement. Active oxygen generated from HSSP, which contains CaO as the main component, may also contribute to disinfection efficacy.…”

Section: Resultsmentioning

confidence: 99%

Ability of Heated Scallop-Shell Powder to Disinfect Staphylococcus aureus Biofilm

Sawai

Ko-jiro

Kikuchi

2013

FSTR

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The ability of heated scallop-shell powder (HSSP) to disinfect Staphylococcus aureus biofilm was investigated. A biofilm of S. aureus NBRC 13276 was produced on a glass plate. Scallop-shell powder was exposed to heat treatment at 1000℃ in air for 1 h, followed by immersion of the biofilm plate into the HSSP slurry. After treatment, the disinfection ability of the HSSP toward the biofilm was measured nondestructively and quantitatively using a conductometric assay. Disinfection efficacy against S. aureus biofilm increased with HSSP concentration and treatment time. HSSP treatment (10 mg/mL, pH 12.5) of 60 min completely eliminated the biofilm bioactivity (which was approximately 10 7 CFU/cm 2 ). In contrast, treatment with NaOH solution (pH 12.5) at a pH identical to the HSSP slurry and treatment with sodium hypochlorite (200 µg/mL) caused an approximately four-to five-order reduction in activity. Fluorescence microscopy confirmed that no viable cells remained on the plate after HSSP treatment. Although alkaline and sodium hypochlorite treatments had a stripping effect on the biofilm, many viable cells remained on the plate. HSSP exerted a disinfection effect against S. aureus biofilm that was greater than that provided by alkaline or sodium hypochlorite treatment. This disinfection effect can be effective for controlling bacteria responsible for food poisoning. The use of HSSP in food processing is expected to not only be a source of minerals but also prolong the shelf-life of foodstuffs and reduce the pollution resulting from discarded shells.

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ChemInform Abstract: Microporous Crystal 12CaO×7Al₂O₃ Encaging Abundant O^‐ Radicals.

Cited by 13 publications

References 1 publication

Diagnostic Features of EPR Spectra of Superoxide Intermediates on Catalytic Surfaces and Molecular Interpretation of Their g and A Tensors

Diagnostic Features of EPR Spectra of Superoxide Intermediates on Catalytic Surfaces and Molecular Interpretation of Their g and A Tensors

Phase Equilibria in the System Al2O3-CaO-CoO and Gibbs Energy of Formation of Ca3CoAl4O10

Ability of Heated Scallop-Shell Powder to Disinfect Staphylococcus aureus Biofilm

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