Compounds consisting of [M(1,2-disila-[3n]crown-n)] (M = Mg, Ca, Sr, Ba; n = 5, 6) and [Ba(1,2-disilabenzo[18]crown-6)] cations and different anions were obtained by equimolar reaction of the hybrid disila-crown ethers 1,2-disila[15]crown-5 (1), 1,2-disila[18]crown-6 (2) and 1,2-disila-benzo[18]crown-6 (7) with alkaline earth metal salts. Even with strongly coordinating anions such as Br or I s...

Inorganic anions were separated on a reversed-phase stationary phase dynamically modified with crown ether as a selector in capillary ion chromatography. The eluent contained crown ether, acetonitrile and a salt. Free and cation-trapped crown ether molecules in the eluent were adsorbed on a hydrophobic stationary phase such as triacontyl-functionalized silica (C30). The eluent cations trappe...

Calix[4]-bis-2,3-naphtho-crown-6 can be used to discriminate between methylammonium and other organic ammonium ions. An electrode based on this ionophore, potassium tetrakis(p-chlorophenyl)borate (20 mol% relative to the ionophore) as an ionic additive and bis(2-ethylhexyl) sebacate as a solvent mediator in a poly(vinyl chloride) membrane matrix, displayed higher selectivity for methylammonium ...

D6056 prefabricated abutment includes placement D6057 custom abutment includes placement D6058 abutment supported porcelain/ceramic crown D6059 abutment supported porcelain fused to metal crown (high noble metal) D6060 abutment supported porcelain fused to metal crown (predominantly base metal) D6061 abutment supported porcelain fused to metal crown (noble metal) D6062 abutment supported cast m...

A series of crown ethers, 12-crown-4, 15-crown-5, 18-crown-6, and dibenzo-30-crown-10, are examined as a possible means of shifting the mobilities of peptide ions. In this approach, a crown ether is added to a solution containing a mixture of peptides and is electrosprayed into the gas phase in order to create distributions of peptide-crown complexes. The ion complexes have different mobilities...

crown fractures account for the majority of dental traumas if handled properly, prognosis of the pulp following a traumatic crown fracture can be favorable. the present case report focuses on the treatment of a traumatized mature permanent incisor with exposed pulp that was treated with the novel technique of miniature pulpotomy using calcium-enriched mixture (cem) cement. one-year follow-up re...

Complexes of the oxa-thia macrocycles [18]aneO4S2, [15]aneO3S2 and the oxa-selena macrocycle [18]aneO4Se2 (L) of types [MCl2(L)]FeCl4 (M = Sc or Y) were prepared from [ScCl3(thf)3] or [YCl2(THF)5][YCl4(THF)2] and the ligand in anhydrous MeCN, using FeCl3 as a chloride abstractor. The [MI2(L)]I, [LaI3(L)] and [LuI2(L)]I have been prepared from the ligands and the appropriate anhydrous metal trii...

A numerical rat ing system to del ineate crown classes of southern hardwoods is described. The system is bused on four cri ter ia: (I) amount o f direct sunlightfrom above, (2) amount of direct sunlightfrom the s ides, (3) crown balance, and (4) relat ive crown size . The total point value assigned places the tree within one o f the,four crown classes . The rat ing system can be used to train i...

This article reports on the use of a natural tooth crown to repair substantial defects caused by caries. A 50 y old woman wished to have a mandibular left-side third molar extracted. Concurrently, the patient voiced concerns about the metal collar of a premolar. It was decided to extract the third molar and to use this tooth to perform an autologous tooth crown transplant at the upper second pr...

Crown and bridge have life span of many years but they fail for a number of reasons. Over the years, many devices have been designed to remove crowns and bridges from abutment teeth. While the removal of temporary crowns and bridges is usually very straightforward, the removal of a definitive cast crown with unknown cement is more challenging. Removal is often by destructive means. There are a ...