Purpose. To analyze the stress distribution in an endodontically treated maxillary central incisor restored with various post-core systems and assess the benefit of ferrule using finite element analysis. Material and Methods. Twelve models with metal ceramic crown were created based on the combination of three types of post-core systems (titanium post-composite resin core, nickel-chromium post-...

Heteroatom addition reactions to unactivated alkynes are thought to be best mediated by transition-metal catalysts such as palladium and gold. Recent studies by Hammond and co-workers and others demonstrate that cyclizations of alkynes with nitrogenand oxygen-containing nucleophiles are possible using stoichiometric amounts of tetra-n-butylammonium fluoride. However, these examples appear to be...

A large variety of different interactions between the chalcogen atoms, Q, occur in the solid state structures of polyselenides and polytellurides, including both molecular and infinite units. The simplest motifs are classical Q(2)(2-) dumbbells and nonlinear Q(n)(2-) chains (n = 3, 4, 5, ..), e.g. found in alkali metal polychalcogenides. In addition, nonclassical so-called hypervalent motifs ex...

We have carried out molecular-dynamics simulations for nonmetallic fluid mercury in liquid and vapour phases using a Lennard-Jones type effective potential and shown that the structure factors S(Q) and the dynamic structure factors S(Q,ω ) of nonmetallic fluid mercury obtained by our MD simulations are in good agreement with recent x-ray diffraction and inelastic x-ray scattering experiments. W...

our civilization is based on metals, among other life supports. the existing ore deposits are becoming rapidly depleted by almost exponentially increasing demand and production and major new ore discoveries are needed. mineral exploration is supported by modern tools and scientific ideas, but geological characteristics of orebodies and their rock associations have still to be visualized.the tim...

This study aims to explore the relationship between human enteric viruses found in town-scale surface water sources and certain chemical contaminants present water. From October 2010 April 2012, samples were collected analyzed using a combination of biophysical molecular techniques detect presence adenoviruses (HAdV) enteroviruses (HEV) as well parameters predictors for virus survival. The conc...