Nanoscale analysis may be used to design new types of mucoadhesive polymers. Understanding of the surface interactions between hydrophilic polymer surfaces and mucins can lead to improved adhesive bonding by hydrogen bonding. Alternatively, decoration of a mucoadhesive polymer surface with tethers of linear and block copolymers containing neutral or ionizable structures provides increased inter...

Helical chiral 2-aminopyridinium ions were designed as a significantly more acidic (active) dual hydrogen-bonding catalyst than commonly used (thio)urea-based systems. The helicene framework was specifically utilized to position an inherently chiral barrier on the hydrogen-bonding side of the catalyst. The catalyst reactivity and enantioselectivity were successfully demonstrated in additions of...

n Part 2 of this article (August 2007), we described multipoint (or common-type) supple mental grounding and bonding between the T(M)GB [notation used here to indicate that the bar may be either the TMGB or TGB, depending on the location within the building] and the telecommunications and information technology equipment (ITE) systems. This installment will focus on the single-point (or insulat...

In a theoretical study of a "defect perovskite" structure of stoichiometry AeTiO(2) (AE = alkaline earth metal, Be, Mg, Ca, Sr, and Ba), we find substantial Ti-Ti bonding tuned by the size of the Ae(2+) cation. The bonding is one-dimensional, partially sigma, partially pi. These formal d(2) systems are expected to be nonmagnetic and metallic. A competing (for same Ae) structural alternative, an...

Adhesive bonding of aluminum holds some possible advantages over the traditional methods of construction in the aerospace industry. However, there is uncertainty about the mechanism of adhesive bonding and the changes occurring during environmental attack which reduce the bond strength. An improved understanding will aid in the development of better techniques for non-destructive testing (NDT) ...

High energy resolution fluorescence detection (HERFD) X-ray adsorption spectroscopy (XAS) is demonstrated as a new tool to identify the geometry of metal adsorption sites and the orbitals involved in bonding. The type of CO adsorption site on a nanoparticular Pt-Al2O3 catalyst is determined. The orbitals involved in the Pt – CO bonding are identified using theoretical FEFF8.0 calculations. In s...

objective: comparing the effect of repeated opening of the container lid of two dentin adhesive systems, prime&bond; nt (p&b; nt) and ibond (ib), on shear bond strength. materials and methods: intact bovine lower incisors (n=60), fixed in acrylic were ran-domly divided into six groups (n=10). groups i and ii were set as control groups. p&b; nt and ib were applied on the samples after five days ...

First-principles total-energy electronic structure calculations based on the full-potential linear-muffin-tinorbital method have been used to study the electronic and mechanical properties of the L12-type ordered nickel-based intermetallics Ni3X ~X5Mn, Al, Ga, Si, Ge!. The calculated values for the equilibrium volume and elastic properties are generally in good agreement with experiments. The l...

Structure and bonding for a series of oxo-bridged and sulphur bridged alkali-metal centers (M-X-M: Li, Na and K; X = O, S) are studied for various M-X-M angles. The structures for these charge-transfer systems are compared with H-X-H. These chargetransfer systems show bonding and structures that are distinctively different from the covalent H-X-H molecules. The singlet-triplet gap for all of th...