Electronic States in Two-Dimensional Triangular Cobalt Oxides: Role of Electronic Correlation

We obtain the electronic states and structures of two-dimensional cobalt oxides, Na$_{x}$CoO$_{2}$ (x=0, 0.35, 0.5 and 0.75) by utilizing the full-potential linear muffin-tin orbitals (FP-LMTO) methods, from which some essential electronic interaction parameters are estimated: the bare on-site Coulomb interaction of cobalt U$_{dd}$=7.5 eV renormalizes to 5 eV for x=0.35, the $pd$ hybridizations t$_{pd\sigma}$ and t$_{pd\pi}$ are -1.40 and 0.70 eV, respectively. The density of states at E$_{F}$ decreases from 6-7 states/eV in the local density approximation (LDA) to about 1.0 states/eV in the LDA+U scheme. The role of the intercalation of water molecules and the microscopic mechanism of the superconductivity in Na$_{0.35}$CoO$_{2}$$\cdot$mH$_{2}$O is discussed.Comment: minor errors correcte

Modified f(G) gravity models with curvature-matter coupling

A modified f(G) gravity model with coupling between matter and geometry is proposed, which is described by the product of the Lagrange density of the matter and an arbitrary function of the Gauss-Bonnet term. The field equations and the equations of motion corresponding to this model show the non-conservation of the energy-momentum tensor, the presence of an extra-force acting on test particles and the non-geodesic motion. Moreover, the energy conditions and the stability criterion at de Sitter point in the modified f(G) gravity models with curvature-matter coupling are derived, which can degenerate to the well-known energy conditions in general relativity. Furthermore, in order to get some insight on the meaning of these energy conditions, we apply them to the specific models of f(G) gravity and the corresponding constraints on the models are given. In addition, the conditions and the candidate for late-time cosmic accelerated expansion in the modified f(G) gravity are studied by means of conditions of power-law expansion and the equation of state of matter less than -1/ 3 .Comment: 13 pages, 4 figure

Growth Mechanism and Structural Correlations of Hydroxyapatites on Surface Functionalized Carbon Fibers

In this study, hydroxyapatites were deposited on surface modified carbon fibers using a simulated body fluid; different amounts of COOH functional group were formed on the fiber surfaces by different degrees of KOH pretreatment. The effect of the surface functional group on the growth features of the hydroxyapatite crystals was analyzed, and the detailed stacking and structural correlations of the grown crystals to the substrate carbon fibers were examined to realize the mineralization mechanism. It was observed that hydroxyapatite nanocrystallites longitudinally constructed a crystal chain along [211] direction; several aligned crystal chains were then bundled to form a spindle structure which ultimately composed differently featured coatings. A mild KOH pretreatment created a small amount of functional group that activated few sites for hydroxyapatite nucleation compliant to the COOH bond structure, yielding a horizontally oriented olive structure under an orientation correlation HAP [112] or [211]//C [100]. A severer treatment induced more nucleation sites; attributed to the repulsion between the close COO(-) ligands, the bond structure was bent, leading to the radially aligned and ball-featured growth of hydroxyapatites with a different correlation HAP [112] or [211] //C [002]. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.064201jes

Composition and non-volatile taste components of Hypsizigus marmoreus

Two strains of Hypsizigus marmoreus (Peck.) Bigelow (Tricholomataceae) are successfully cultivated and commercially available in Taiwan, and their composition and non-volatile taste components of fruit bodies and mycelia were studied. Both fruit bodies were higher than mycelia in contents of carbohydrate, ash and fiber but lower in contents of fat and protein. Total sugar and polyol contents were 45.47-91.50 mg/g and total free amino acid contents were in the descending order of white strain fruit bodies (122.97) > normal strain fruit bodies (95.94) > white strain mycelia (53.20) > normal strain mycelia (46.87 mg/g). Monosodium glutamate-like components of both fruit bodies were 3-4-fold higher than those of both mycelia. Total 5'-nucleotides contents were 6.43-11.02 mg/g with white strain fruit bodies being the highest. Equivalent umami concentrations of both fruit bodies were higher than those of mycelia, Overall, H. marmoreus fruit bodies possessed highly intense umami taste. (C) 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved

Antioxidant Properties of Novel Solid-State Fermented Culinary-Medicinal Mushroom and Fungi Products

Four culinary-medicinal fungi and mushrooms (Cordyceps sinensis, Termitomyces albuminosus, Antrodia camphorata, and A. salmonea) were individually inoculated into different cooked grains, and new products were formed after fungal fermentation and their antioxidant properties studied. The effectiveness of ethanolic extracts in antioxidant activities was in the descending order: the grains > products > mycelia. EC(50) values of the hot water extract from four products in reducing power were 2.14-10.11 mg/mL, whereas those of the ethanolic extracts were 2.56-71.34 mg/mL. With regard to scavenging ability, all EC(50) values of both extracts from 12 samples were less than 13 mg/mL, except for the hot water extract from A. camphorata mycelium. EC(50) values of both extracts from four products in chelating ability were 1.50-9.96 mg/mL, except for the hot water extract from Cordyceps-fermented polished rice and the ethanolic extract from A. camphorata-fermented embryo rice. Total phenol contents of both extracts from mycelia, products, and grain substrates were 2.45-12.26, 3.24-13.13, and 1.15-7.74 mg/g, respectively. Overall, four medicinal mushroom and fungi-fermented products were relatively effective in the antioxidant properties assayed and might be potential antioxidants for application in food products