NO reduction by C3H6 over apatite-type A10(PO4)6(OH)2 (A?=?Ca and Sr)-supported Pt catalysts

A₁₀(PO₄)₆(OH)₂ (A = Ca and Sr)-supported Pt catalysts were prepared and their catalytic activity in NO reduction were investigated. The Sr₁₀(PO₄)₆(OH)₂-supported catalyst had high catalytic activity in the C₃H₆?CNO?CO₂ reaction; the activity was higher than that of the ??-Al₂O₃-supported catalyst at 300 °C. The basicity of the apatite supports would affect the chemical state of Pt on catalyst, resulting in promotion of NO reduction.     

Silver delafossite nitride, AgTaN2?

A new silver nitride, AgTaN₂, was synthesized from NaTaN₂ by a cation-exchange reaction, using a AgNO₃-NH₄NO₃ flux at 175 °C. Its crystal structure type is delafossite (R3¯m) with hexagonal lattice parameters of a=3.141(3) Å, c=18.81(2) Å, in which silver is linearly coordinated to nitrogen. Energy dispersive X-ray analysis and combustion nitrogen/oxygen analysis gave a composition with atomic ratios of Ag:Ta:N:O as 1.0:1.2(1):2.1(1):0.77(4), which is somewhat Ta rich and indicates some oxide formation. The X-ray photoelectron spectroscopy analysis showed a Ta- and O-rich surface and transmission electron microscope observation exhibited aggregates of ca. 4-5 nm-sized particles on the surface, which are probably related to the composition deviation from a AgTaN₂. The lattice parameters of stoichiometric AgTaN₂ calculated by density functional theory agree with the experimental ones, but the possibility of some oxygen incorporation and/or silver deficiency is not precluded.     

Evaluation of TA10 broth for recovery of heat- and freeze-injured Salmonella from beef

The Bacteriological Analytical Manual (BAM) Salmonella pre-enrichment broth [lactose (LAC) broth], buffered peptone water, and universal pre-enrichment (UP) broth were compared with TA10 broth, developed in our laboratory, for recovery of heat- and freeze-injured Salmonella (55 degrees C for 2-20 min and -20 degrees C for 2 months, respectively) from beef. Beef samples were contaminated with single Salmonella serovars, and contamination levels of 0.44 to <0.001 most probable number (MPN)/g and 0.74 to 0.14 MPN/g were used for heat- and freezing-induced injury studies, respectively. Twenty test portions (25 g) of the contaminated beef were pre-enriched in each broth, and the BAM Salmonella culture method was used thereafter. There was a significant difference (chi2 = 7.73) in recovery of heat-injured Salmonella between TA10 broth and LAC broth, 189 (67.5%) versus 156 (55.7%) positive samples, respectively, determined by plating onto selective agars and identification by biochemical tests. For the recovery of freeze-injured Salmonella, there was a significant difference (chi2 = 24.7) between TA10 and LAC broth, 189 (72.7%) versus 133 (51.2%) positive samples, respectively. TA10 broth was more effective than LAC broth and UP broth for recovery of freeze-injured Salmonella. The results indicate that TA10 broth should be used instead of LAC broth for testing of beef that may be contaminated with heat- and freeze-injured Salmonella spp.     

A-type cranberry proanthocyanidins inhibit the RANKL-dependent differentiation and function of human osteoclasts

This study investigated the effect of A-type cranberry proanthocyanidins (AC-PACs) on osteoclast formation and bone resorption activity. The differentiation of human pre-osteoclastic cells was assessed by tartrate-resistant acid phosphatase (TRAP) staining, while the secretion of interleukin-8 (IL-8) and matrix metalloproteinases (MMPs) was measured by ELISA. Bone resorption activity was investigated by using a human bone plate coupled with an immunoassay that detected the release of collagen helical peptides. AC-PACs up to 100 μg/mL were atoxic for osteoclastic cells. TRAP staining evidenced a dose-dependent inhibition of osteoclastogenesis. More specifically, AC-PACs at 50 μg/mL caused a 95% inhibition of RANKL-dependent osteoclast differentiation. This concentration of AC-PACs also significantly increased the secretion of IL-8 (6-fold) and inhibited the secretion of both MMP-2 and MMP-9. Lastly, AC-PACs (10, 25, 50 and 100 μg/ml) affected bone degradation mediated by mature osteoclasts by significantly decreasing the release of collagen helical peptides. This study suggests that AC-PACs can interfere with osteoclastic cell maturation and physiology as well as prevent bone resorption. These compounds may be considered as therapeutic agents for the prevention and treatment of periodontitis.     

Low-temperature phase of Li2FeSiO4: crystal structure and a preliminary study of electrochemical behavior

A nearly single-phase of a low-temperature (LT) phase of Li(2)FeSiO(4) is prepared by a hydrothermal method at 150 °C. We report the detailed crystal structure of LT-Li(2)FeSiO(4) (S.G. Pmn2(1)) by applying Rietveld/MEM analysis to the synchrotron XRD pattern. LT-Li(2)FeSiO(4) shows 150 mA h g(-1) as the positive electrode materials of rechargeable batteries.     

Synthesis of thermosensitive polymer/mesoporous silica composite and its temperature dependence of anion exchange property

An anion exchanger consisting of amino-functionalized MCM-41 type mesoporous silica coated with temperature-responsive polymer, poly(N-isopropylacrylamide) (PNIPAM), was synthesized in this study. The structure of this composite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and elemental analysis. The XRD pattern showed that the synthesized composite had the ordered hexagonal structure and the interplanar spacing, d(100), was around 40?. The amount of surface-grafted thermosensitive polymer was estimated to be about 0.8wt.% by elemental analysis. The adsorption-desorption behavior of methyl orange in this synthesized material depended on the temperature of aqueous solution: at 25°C, the reversible adsorption-desorption of methyl orange was repeated with changing pH of the solution; at 40°C, the methyl orange was not adsorbed and desorbed independent of pH of the solution.     

UV luminescent organic-capped ZnO quantum dots synthesized by alkoxide hydrolysis with dilute water

A novel synthesis route to organic-capped and colloidal ZnO quantum dots (QDs) has been developed. Specifically, zinc-di-t-butoxide and zinc-di-n-butoxide are hydrolyzed by very dilute water (400-600 mass ppm) in hydrophilic benzylamine and polymerized to ZnO by dehydration and/or a butanol elimination reaction. Growth of the ZnO QDs and exchange of the surface capping ligand from the hydroxyl groups and/or benzylamine to the oleylamine occur by heating the colloidal solution after addition of the oleylamine at 100-180°C. The final ZnO QDs with diameters in the range of 3-7 nm are highly dispersible in various organic solvents. The ZnO QDs exhibit the quantum size effect upon UV emission; it was controlled between 3.39 and 3.54 eV in the present study. The defect-related Vis emission decreased and the UV emission becomes dominant when zinc-di-n-butoxide with a 99.99% zinc purity is used as the starting material. The intensity of the photoluminescence UV emission is 1.5 times higher than that of the Vis emission.     

Solid-state thiotropolone: an extremely rapid intramolecular proton transfer

Through variable-temperature solution-state NMR and molten- and solid-state CP/MAS (13)C NMR spectra, thiotropolone is found to exist as two rapidly equilibrated tautomeric structures, thione and enethiol, even in the solid state far below the melting point. The crystal structure shows an almost perpendicular packing, suggesting that the intramolecular hydrogen bond is dominant.     

Enantioselective total synthesis of (+)-lysergic acid, (+)-lysergol, and (+)-isolysergol by palladium-catalyzed domino cyclization of allenes bearing amino and bromoindolyl groups

Enantioselective total synthesis of the biologically important indole alkaloids (+)-lysergol, (+)-isolysergol, and (+)-lysergic acid is described. Key features of these total synthesis include (1) a facile synthesis of a chiral 1,3-amino alcohol via the Pd(0)- and In(I)-mediated reductive coupling reaction between L-serine-derived 2-ethynylaziridine and formaldehyde; (2) the Cr(II)/Ni(0)-mediated Nozaki-Hiyama-Kishi (NHK) reaction of an indole-3-acetaldehyde with iodoalkyne; and (3) Pd(0)-catalyzed domino cyclization of an allene bearing amino and bromoindolyl groups. This domino cyclization enabled direct construction of the C/D ring system of the ergot alkaloids skeleton, as well as the creation of the C5 stereogenic center with transfer of the allenic axial chirality to the central chirality.     

An unsymmetrical behavior of reactant units in the Kolbe�CSchmitt reaction

Paths of the Kolbe?CSchmitt reaction were investigated by the use of RB3LYP/6-311(+)G(d,p) density functional theory calculations. In a monomer model composed of C₆H₅O^?, Na⁺ and CO₂ affording sodium salicylate [C₆H₄(OH)CO₂ ^?Na⁺], a proton-shift step (Z Naturforsch 57a:812, 2002) was found to have an unrealistically large activation energy. In consideration of the phenol volatilization in the Kolbe??s experiment and the need of the linearity of the proton-transfer path, a dimer model was constructed. Again, a mutual proton-transfer step has a large activation energy. Alternatively, in a dimer model, a transfer path where the phenoxide ion in one monomer acts as a proton acceptor was found to have a reasonable energy. Addition of one more sodium ion leads to the significant lowering of activation energies. Thus, in the dimer, two monomers behave differently (A?+?A????A?+?B); one is as if it were a catalyst.