BACKGROUND The aim of this study was to compare the abrasivity of various commercially available toothpastes that claim to reduce dentin hypersensitivity. METHODS Dentin discs were prepared from 70 human extracted molars. The discs were etched with lemon juice for 5 min, and one half of the discs were covered with aluminum tape. Following this, they were brushed with 6 different toothpastes, ...

The carbonatite problem can be stated as follows: Are carbonatites genetically related to sedimentary carbonate rocks, or are they derived from a silicate parent material? The isotopic composition of strontium in 21 carbonatites and in several related alkaline rocks has been determined. The mean Sr87/$r86 ratio for the 21 carbonatites is 0.7065 + 0.0003. The Sr87/sr86 ratios of sedimentary carb...

Strontium titanates were prepared with different morphologies by varying the ratio of solvents used during synthesis. The effects morphology and solvent (ethylene glycol to water) investigated both on structure photocatalytic activity samples. Structural properties determined X-ray diffraction, scanning electron microscopy, diffuse reflectance spectroscopy, nitrogen adsorption measurements. sam...

The interactions between electric field and the mechanical properties of materials are important for the applications of microelectromechanical and nanoelectromechanical systems, but relatively unexplored for nanoscale materials. Here, we observe an apparent correlation between the change of the fractured topography of Nb-doped SrTiO3 (Nb:STO) within the presence of a built-in electric field re...

Stable Strontium. Elemental strontium (atomic number 38) occurs naturally in the earth's mantle as a mixture of four stable isotopes, Sr, Sr, Sr, and Sr, and is present everywhere in very dilute concentrations. It is very similar to calcium in its environmental and physiological behavior. Strontium is generally found in molecular compounds with other elements. Commercially important strontium m...

In the deltaic plain of the Ganges-Meghna-Brahmaputra rivers, arsenic concentrations in groundwater commonly exceed regulatory limits (50 μg l) because FeOOH is microbially reduced and releases its sorbed load of arsenic to groundwater. Neither pyrite oxidation nor competitive exchange with fertilizer-phosphate contribute to arsenic pollution. The most intense reduction, and so severest polluti...