Noboritomycins A and B, two new polycyclic ionophoric polyethers were isolated from a strain of Streptomyces noboritoensis. The crystal structure and absolute configuration of noboritomycin A were established by X-ray analysis of its silver salt C43/63O14Ag. Noboritomycin A is the first metabolic polyether possessing two carboxylic acid functions on the carbon backbone (C-31), namely a free aci...

Novel polyether antibiotics X-14873A, X-14873G, and X-14873H are produced by the fermentation of Streptomyces sp. X-14873 (ATCC 31679). This report presents taxonomic studies and fermentation conditions for the antibiotic producing culture. The antibiotics are mainly active against Gram-positive bacteria. The ionophore properties of X-14873A are also characterized.

Triptycene-derived macrotricyclic polyether containing an anthracene unit is a powerful host for 1,2-bis(pyridium)ethane, diquat and 2,7-diazapyrenium salt with association constants of the 1 : 1 complexes at >10(5) M(-1). Crystal structures showed that π-π stacking interactions between the host and the guests play an important role in the formation of the stable complexes.

A large covalent cage incorporating two porphyrins attached by four long and flexible polyether chains each bearing two 3-pyridyl ligands was synthesized from a DABCO-templated olefin metathesis reaction. The X-ray structure of the cage with the DABCO coordinated inside the cavity to the two zinc(II) porphyrins reveals a highly symmetric structure.

Polyalcohol is an environmentally friendly anti-collapse lubricant commonly used in water-based drilling fluids. It generally composed of the single polyether or polyol, but its lubricity and inhibition can’t satisfy application current fluid systems well. Consequently, laboratory has carried out research on compound polyalcohol. The samples are mixed with lauryl polyether, nonylphenol Tween 80...

Good footwear should be comfortable, long-lasting and fit for purpose, polyurethanes allow designers to meet all of these objectives. Polyurethanes are used in the industry make insoles shoe soles.There two types PU soles a polyether polyester based sole. Polyether have high resistance against hydrolysis low oil while resistance. In this work thermal mechanical properties elastomers with polols...

BACKGROUND The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II) ions in in vivo experiments, despite so far no Pb(II)-containing compounds of defined composition ha...

UNLABELLED PROBLEM/AIMS: Thin sections of impression materials are susceptible to tearing in gingival crevices and interproximal spaces. This study measures the tear strength of six fast and regular set impression materials after different setting times and at different tearing rates. MATERIALS/METHODS Tear strength specimens were prepared of four addition silicone materials: Aquasil (Dentspl...

Intracranial pressure and volume vary considerably between hydrocephalic patients, and with age, health and haemodynamic status; if left untreated, intracranial pressure rises and the ventricular system expands to accommodate the excess cerebrospinal fluid, with significant morbidity and mortality. Cerebrospinal fluid shunts in use today have a high incidence of failure with shunt obstruction b...

AIMS To investigate the effect of the storage period on the accuracy of recently developed elastomeric materials. METHODS Simultaneous impressions of a steel die were taken using a polyether (I: Impregum Soft Heavy and Light body, 3M ESPE) and vinyl polysiloxane (P: Perfectim Blue Velvet and Flexi-Velvet, J.Morita). The trays were loaded with the heavy-bodied impression materials while the li...