siilver tetrafluoroborate complex of 5.11.17.23-tetra-tert-butyl-25-26,27,28-tetrakis (diphenylphosphinoylmethoxy)calyx[4]arene (l) has been synthesized by reaction of silver tetrafluoroborate and l in dichloromethane at room temperature. the complex formed has a 1:1 metall/ligand ratio. 1h and 31p nmr data support an encapsulated structure of the complex in which silver ion is located inside t...

three high-silica mordenite zeolites differing in sio440, ratio were prepared by direct synthesis without using any template. the products si02/a120, ratio is influenced by the starting gel composition. this ratio is increased upon ion-exchange with nh,cl and subsequent calcination to prepare protonic mordenite. the protonic mordenites with si02/a1203ra tios of 14.6,29.2 and 34.6 were character...

In freshwater crustaceans and in both freshwater and marine fish, the key mechanism of acute silver toxicity involves ionoregulatory impairment. An inhibition of the Na+ ,K+-ATPase located at the basolateral membrane of the gill epithelium seems to be the key site for silver toxicity. However, studies to determine if the same mechanism of toxicity is occurring in marine invertebrates, which als...

Abstract Purpose of Review Zeolite is an aluminosilicate compound having a wide spectrum applications in medicine and dentistry. Several articles were published combining zeolites with various other elements for different This review aims to provide detailed on the origin zeolites, their physical chemical properties possible as dental materials. Recent Findings Zeolite-based hybrid films can be...

traditional systems for olefin/paraffin separation, like low-temperature distillation, are expensive and very energy consuming, and therefore, alternative separation methods are desired. facilitated transport membranes are new tools for this separation to be substituted in large scale separation of olefin-paraffin mixtures. to design a membrane process for olefin-paraffin separation, equilibriu...

a method for the controllable synthesis of silver nanoparticles based on a complexing agent method was developed. citric acid was used as a complexing agent. the effect of ph (1.6 to 5.17) on the size and net height (as obtained from xrd analyses) of silver nanoparticles was investigated. the nanoparticles (10 to 40 nm) were characterized using xrd, tem, sem, edx, uv-vis spectroscopy and tg/dtg...

BACKGROUND Tumor patients and patients after traumas are endangered by a reduced immune defense, and a silver coating on their megaprostheses may reduce their risks of infection. The aim of this study was to determine the silver ion concentration directly measured from the periprosthetic tissue and the influence on the clinical outcome. MATERIAL AND METHODS Silver ions were evaluated in 5 mL ...

The Ag K-edge EXAFS measurements have been carried out at 50 K for fully Ag+-exchanged zeolite 4A (Ag-4A) dehydrated at different temperatures under vacuum. In the Fourier transforms of the EXAFS oscillation the two distinct peaks appear around 2.2 A and 3.0 A, and a shoulder around 2.8 A. The structural parameters (distance, coordination number and root mean square displacement) were derived b...

Antimicrobial packaging, an active packaging concept, can be considered an extremely challenging technology that could have a significant impact on shelf-life extension and food safety of meat and meat products. Use of antimicrobial substances can control the microbial population and target specific microorganisms to provide higher safety and quality products. Many classes of antimicrobial comp...