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...

respirators are commonly used to protect workers against workplace airborne contaminants, but this equipment may become a safety hazard by creating discomfort, disorientation and postural instability. although postural stability is critical to workers, especially those working near moving objects or on surfaces where a loss of balance may become life threatening, little attention has been given...

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...

Knowledge of tree-crown parameters such as height, shape, and crown closure is desimble in forest and ecological studies, but those pammeters are difficult to measure on the ground. The stereoscopic capability of high-resolution aerial images provides a method for crown-surface reconstruction. However. 'existing digital photogrammet~packages, designed to map terrain surfaces. cannot accuratelv ...

As a reduced wearing time reduces quickly the effectiveness of the protection (see e.g. table 1) it is of utmost importance that persons with hearing loss do not get into a vicious circling as sketched in fig. 2 and that they can keep wearing their protection at all times. This can be achieved by simultaneously offering: • Protections with a very high wearing comfort and • Protections that do n...

We studied the electric properties of phosphatidylcholine bilayers modified with crown ether (dibenzo[18] crown-6). The studies were carried out for various crown ether concentrations in forming solutions and various potassium ion concentrations in electrolyte solutions. The presence of crown ether in the membrane influences the membrane's impedance; there is a reduction in its resistivity, a d...

Mismatched complexes of the alkali metals cations Li+ and Na+ were synthesized from 1,2-disila[18]crown-6 (1 and 2) and of K+ from 1,2,4,5-tetrasila[18]crown-6 (4). In these alkali metal complexes, not all crown ether O atoms participate in the coordination, which depicts the coordination ability of the C-, Si/C-, and Si-bonded O atoms. Furthermore, the inverse case—the coordination of the larg...

Diazahexathia-24-crown-8 (2) has been isolated from the reaction mixture during the preparation of monoazatrithia-12-crown-4 (1). When N-Boc protected bis(2-chloroethyl)amine was employed as a starting material, N-Boc protected monoazatrithia-12-crown-4 (3) and N-Boc protected diazahexathia-24-crown-4 (4) were separated easily. Double-armed diazahexathia-24-crown-8 having two 3',5'-dichlorobenz...