Rare earth ion-doped yttrium oxide (Y2O3) nanocrystals are nontoxic and can be prepared as upconversion materials for cellular imaging, but they do not suspend well in water. In contrast to their tendency to dissolve in acidic media, yttria (Y2O3) nanoparticles readily react with phosphonic acids to give phosphonate-bonded yttria particles. Through the choice of phosphonic acid, the hydrophilic...

The purpose of this study was to compare the fracture resistance and fracture mode of single implant-zirconium coping combinations using zirconium and titanium abutments and to analyze the stress distribution pattern using three-dimensional finite elements analysis. Twenty implants with titanium and zirconium abutments were randomly divided into two groups (n = 10) and into resin blocks. Zircon...

Aim: The aim of this in vitro study was to evaluate imaging artifacts induced by Titanium, Zirconium, Titanium-Zirconium abutments in CT, MRI and CBCT imaging modalities.Methods: A 4×8mm titanium fixture was inserted in a dry human mandible. Titanium, Zirconium and Titanium–Zirconium abutments measuring 10.5 mm in height are located on the fixture, one by one. Each abutment was scan...

The structure of solid zirconium tetrachloride is known from X-ray studies[l] to consist of extended chains of distorted octahedra with two bridging chlorine atoms between adjacent zirconium atoms. Although the unit cell possesses a center of symmetry, the two pairs of bridging chlorine atoms attached to a given zirconium atom are not trans to each other. The factor group symmetry thus is C2h w...

The p-nitrophenyl ethyl phosphonate esters have been shown to inhibit complement-dependent erythrophagocytosis when exposed to guinea pig polymorphonuclear leukocytes prior to the initiation of phagocytosis. Inhibition of phagocytosis occurred in a manner characteristic of the well-defined capacity of phosphonate esters to inactivate serine esterases: inhibition was irreversible, dependent upon...

Phosphonate derivatives were prepared using multicomponent reactions of dialkyl acetylenedicarboxylate with 4-hydroxycumarine in the presence of trimethyl or triphenyl phosphite in good yields.

We already reported that an intramolecular benzylation of the imino moiety of bidentate iminopyrrolyl ligands afforded an amido-pyrrolyl complexes 1 and they exhibited better catalytic activity for ethylene polymerization compared to the corresponding bis(iminopyrrolyl) dichloro complexes of zirconium. In this contribution, we prepared amido-pyrrolyl complexes of zirconium (3a-d) and hafnium (4...

Structure and characterization of [Cu26{2,3,5,6-(Me)4C6H-CH2-PO3}18(μ2-OH)4(μ3-OH)6(μ4-Cl)6(μ-OH2)2(OH2)2(MeCN)4]·6MeCN·15H2O (1) is reported. Complex 1 is the largest discrete molecular homometallic transition metal phosphonate assembly. Remarkably, this gigantic molecular phosphonate has been prepared at room temperature using a normal solution synthetic method.

A set of small nonpeptidic diaryl phosphonate inhibitors was prepared. The phosphonate derivatives were synthesized through Birum-Oleksyszyn reaction followed by reduction of the nitro-group which undergo to Boc-protected guanidine derivatives. After removing of Boc-group by TFAA/DCM afford the guanidine phosphonates.

Vertical scanning interferometry and XPS show the reaction of CaCO3 with the hydration retarder nitrilo-tris-(methylene)phosphonic acid follows a pathway of dissolution of the calcium followed by precipitation of a calcium phosphonate; subsequent surface reorganization/restructuring of the calcium phosphonate exposes the underlying CaCO3 for further hydration.