OBJECTIVE Elastomeric materials play an important role in the orthodontic practice, including the retraction force to move teeth into extraction sites, closing diastemas, selective shifting of the midline and generalized space closure. Frictional resistance and ligating strength of archwire-bracket-ligature complex occurs during utilization of elastomeric and metallic ligatures when orthodontic...

in this work, we investigate the transfer of some homological properties from a ring $r$ to its amalgamated duplication along some ideal $i$ of $r$ $rbowtie i$, and then generate new and original families of rings with these properties.

for a ring endomorphism $alpha$ and an $alpha$-derivation $delta$, we introduce a concept, so called skew $pi$-armendariz ring, that is a generalization of both $pi$-armendariz rings, and $(alpha,delta)$-compatible skew armendariz rings. we first observe the basic properties of skew $pi$-armendariz rings, and extend the class of skew $pi$-armendariz rings through various ring extensions. we nex...

Recent research in perinatal pathology argues that analyzing properties of the placenta may reveal important information on how certain diseases progress. One important property is the structure of the placental blood vessels, which supply a fetus with all of its oxygen and nutrition. An essential step in the analysis of the vascular network pattern is the extraction of the blood vessels, which...

In the title hydrate, C(10)H(10)O(4)·H(2)O, the six-membered aliphatic ring that is fused to the benzene ring has a sofa shape, with the hy-droxy group in the 3-position (that represents the sofa back) of the aliphatic ring occupying a quasi-axial position. The hy-droxy group of the aromatic ring is hydrogen-bond donor to the carbonyl O atom; other O-H⋯O hydrogen bonds link the organic mol-ecul...

In the title compound, C(17)H(11)N(5)S(2), the dihedral angles formed between the triazole ring and the benzene ring and the 1,3-benzothia-zole ring system are 8.67 (8) and 13.90 (9)°, respectively. The conformation of the triazolo-thia-diazin-3-yl fused ring system is a twisted half-chair. Overall, the mol-ecule adopts a flattened shape. Supra-molecular helical chains along the a axis sustaine...

The title compound, C(11)H(13)NO(2)S(2), contains a 1,3-dithiane ring in an almost ideal chair conformation with the following puckering parameters: Q = 0.7252 (15) Å, θ = 6.71 (13) and ϕ = 50.4 (11)°. The benzene ring occupies an axial position at the dithiane ring. The nitro group is almost coplanar with the benzene ring [O-N-C-C = -3.2 (2)°]. The mol-ecule has an L-shape with a C-C-C-C torsi...

OBJECTIVE To evaluate the effects of the intrastromal corneal ring, a device developed to reduce myopia, on corneal asphericity in a large set of eye bank eyes. METHODS Forty-one deturgesced eye bank eyes were implanted with intrastromal corneal rings of five different thicknesses, ranging from 0.25 mm to 0.45 mm. Corneal asphericity, before and after implantation, was examined using two diff...

All existing observational data relating to the transmission properties of Saturn's rings are discussed. Fromsuch data the optical thickness of the crape ring is determined as a function of its distance from the planet.Limiting values for ring B and a new value for the inner radius of ring B are established. The shape of thepressure curve of a gas cloud evidently associated with rin...