This article contains a survey on the algorithms for space groups and crystallographic groups available in the computer algebra system Gap [9] and in the software packages Carat [25] and Cryst [5].

Objective: The aims of this study were to investigate the release of element from, and the biological response in vitro to, cobalt-chromium alloys and other base-metal alloys used for the fabrication of metal-ceramic restorations. Material and methods: Eighteen different alloys were investigated. Nine cobalt-chromium alloys, three nickel-chromium alloys, two cobalt-chromium-iron alloys, one pal...

Menzel’s commentary is a tightly focused, extended argument and it may be summarized as follows: (a) though Zalta gathers a range of phenomena under a small set of concepts, unfortunately, the framework is a possibilist one; (b) Zalta justifies possibilism by arguing that it provides the simplest and most natural explanation and analysis of such phenomena as ordinary modal discourse; but (c) by...

The simultaneous sputter deposition of gold and silver onto ionic liquids formed bimetallic alloy nanoparticles, which exhibited composition-sensitive surface plasmon resonance, the peak wavelength being red-shifted with an increase in the surface area of the gold foil targets sputtered.

The literature related to stress distribution in porcelain-fused-to-gold restorations and the supporting structures has been reviewed by Craig, El-Ebrashi. and Peyton.1 They used two-dimensional composite photoelastic models to study the stress distribution in labial-lingual and mesial-distal sections of a central incisor that contained a porcelainfused-to-gold or a porcelain crown restoration....

Cathode electrodes of the Si(Li) detector elements of the SIXA X-ray spectrometer array are formed by gold-palladium alloy contact layers. The equivalent thickness of gold in one element was measured by observing the characteristic L-shell X-rays of gold excited by monochromatised synchrotron radiation with photon energies above the L3 absorption edge of gold. The results obtained at 4 differen...

PURPOSE A 3-dimensional finite element model consisting of a bone block and 2 simulated premolar crowns supported by 2 adjacent cylindric implants without immediately surrounding cortical bone was generated and used to investigate the effects of prosthesis materials and prosthesis splinting on the peri-implant bone stress under static loads. MATERIALS AND METHODS The peri-implant maximum equi...

We report a novel strategy for the fabrication of nanoporous gold (NPG) films. The fabrication process involves the electrodeposition of a gold-tin alloy, followed by subsequent chemical dealloying of tin. Scanning electron microscopy (SEM) images show a bicontinuous nanoporous structure formed on the substrates after chemical dealloying. Energy dispersive x-ray (EDX) analysis indicates that th...

OBJECTIVE The purpose of this study was to investigate whether extension of the custom base is necessary for enhancement of bond strength, by comparing the debonding forces and residual adhesives of 3 different lingual bracket systems. METHODS A total of 42 extracted upper premolars were randomly divided into 3 groups of 14 each for bonding with brackets having (1) a conventional limited resi...

Density functional study of the experimentally observed ligand-protected gold alloy clusters reveal the same stabilization mechanism as in ligand protected pure AuN: the delocalized s-electron subsystem of a high symmetry metal core exhibits a shell closing. On the basis of this observation it is predicted that the substitution of a single Au atom in the well-known Au25(SR)18 compound with Pd, ...