STATEMENT OF PROBLEM The use of dental amalgam as a direct restorative material has been a subject of controversy for many years. The potential safety of amalgam has been questioned because of leakage of elements such as mercury, copper, tin, and silver. PURPOSE This study evaluated the elemental leaching from Tytin dental amalgam placed in deionized water for 2 months. Both mercury vapor and...

The morphology of crystalline precipitates in a solid-state matrix is governed by complex but tractable energetic considerations driven largely by volume strain energy minimization and anisotropy of interfacial energies. Spherical precipitate morphologies are favored by isotropic systems, while anisotropic interfacial energies give energetic preference to certain crystallographically oriented i...

Rhythmic banding of precipitates was first discussed by Raphsel E. Liesegang (1)) hence the name “Liesegang’s rings.” He observed that when a solution of silver nitrate is placed on a gelatine gel containing dilute potassium bichromate, rhythmic banding of the precipitate occurs. If the solutions are in a dish or on a plane surface the precipitate is in concentric rings; if in a test-tube, supe...

When an aqueous solution of the fibroin of Bombyx mori is treated with chymotrypsin, a white precipitate is formed that contains approximately 60% of the nitrogen of the original fibroin, and the remaining 40% of the nitrogen remains in solution in the form of a mixture of water-soluble peptides. These two fractions, the precipitate and the mixture of soluble peptides, we propose to call fracti...

The ability of high (6.73) and low (5.02) pH solutions of lead acetate precipitate of H. rosasinensis petal anthocyanin extract to prevent carbon tetrachloride (CCl4) induced lipid peroxidation in rats has been investigated using plasma malondialdehyde (MDA) level as an index of the process. Relative to its value in the plasma of CCl4 treated extract-free rats, the high pH form (pH 6.73; blue p...

Upon dispersant-assisted exfoliation, pristine carbon nanotubes (CNTs) are divided between the supernatant and precipitate, which makes the determination of dispersant concentration a challenging task. We have developed a thermogravimetric-spectroscopy-based approach to accurately determine the dispersant-assisted CNT (or nanoparticles, in general) concentration in dispersion. A thermogravimetr...

During the cleaning and shaping of the root canal, various irrigants have been used to reduce the residual debris, necrotic tissue, and bacteria, as well as to remove smear layer. Though sodium hypochlorite (NaOCl) is the most common irrigant used in root canal treatment, chlorhexidine (CHX) has been suggested as either an alternative or an adjunct root canal irrigant because of its antimicrobi...

The influence of intermittent positive pressure ventilation on gastro-oesophageal reflux in preterm infants is not known. In many neonatal units, however, concern that ventilation may increase gastro-oesophageal reflux (and therefore aspiration) leads to avoidance of enteral feeding during ventilation. We have therefore performed a crossover study of gastrooesophageal reflux by monitoring lower...

We present the first study relating structural parameters of precipitate-free Ge0.95Mn0.05 films to magnetization data. Nanometer-sized clusters--areas with increased Mn content on substitutional lattice sites compared to the host matrix--are detected in transmission electron microscopy analysis. The films show no overall spontaneous magnetization at all down to 2 K. The TEM and magnetization r...