Crown ethers 12-crown-4 (12C4), benzo-15-crown-5 (B15C5), 18-crown-6 (18C6), nitrobenzo-18-crown-6 (NB18C6) dibenzo-18-crown-6 (DB18C6) and dicyclohexyl-18-crown-6 (DC18C6), dissolved in dichloromethane, are able to form oxonium-ion complexes in contact with aqueous sulfuric and hydrochloric acid solutions. This ability allows the transfer of Cr(VI) oxanions from the acid media, through an ...

BACKGROUND AND PURPOSE We noticed that our instruments were often too hot to touch after preparing the femoral head for resurfacing, and questioned whether the heat generated could exceed temperatures known to cause osteonecrosis. PATIENTS AND METHODS Using an infra-red thermal imaging camera, we measured real-time femoral head temperatures during femoral head reaming in 35 patients undergoin...

This paper presents the study results on stress and deformation of piston crown a biogas engine converted from conventional diesel using dedicated software. The original was modified to reduce compression ratio suit fuel. engine's combustion chamber were changed by modifying heron type. parameters in-cylinder pressure temperature determined thermodynamic simulation software AVL Boost. Research ...

BACKGROUND Complete cast crowns are good alternatives and have best longevity for the restoration of damaged posterior teeth. Occasionally, a crown with clinically acceptable margins, preparation design, and occlusion becomes loose. Providers often debate whether such a crown can be successfully recemented with any degree of confidence that it will not be dislodged under normal masticatory func...

Stability constants in 90% (v/v) DMSO /water mixture were evaluated for the complexes of Ag(I), Co(II), Cu(II), Mn(II), Ni(II), Zn(II), Pb(II), Cr(III) and Fe(III) with the macrocyclic compounds, namely, 15-crown-5, benzo-15-crown-5, 18-crown-6, dibenzo18-crown-6, dicyclohexano-18-crown-6, dibenzo-24-crown-8 and dicyclohexano-24-crown-8 by conductometric titrations. A potentiometric study of co...

We studied the distribution of hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), within hemlock trees for three summer (progrediens) and two winter (sistens) generations in northern Georgia. Eastern hemlock, Tsuga canadensis (L.) Carrière, trees were treated with 0, 10, or 25% of 1.5 g of imidacloprid per 2.5 cm of tree diameter at breast height and fertilized or not in a fa...

Pinus halepensis Mill. is a Mediterranean pioneer forest species with shade intolerance features. The 15 purpose of this study is to better understand how stand fertility and allelopathic properties of adult trees influence 16 shade acclimation of saplings. Crown growth and morphological plasticity were studied under different light, 17 fertilization, and allelopathic conditions in a nursery ex...