The integration of catalyst metals into the graphene-based composites can be a new way to ensure thermal and electronic conductivities of the catalyst support materials in polymer electrolyte membrane fuel cells. In this work, graphene nanosheets were synthesized via a mild and safer chemical route including three major steps: graphite oxidation, ultrasonic treatment and chemical reduction. The...

Tyrosinase exhibits catalytic activity for the ortho-hydroxylation of monophenols to diphenols as well as their subsequent oxidation to quinones. Owing to polymerization of these quinones, brown-coloured high-molecular-weight compounds called melanins are generated. The latent precursor form of polyphenol oxidase 4, one of the six tyrosinase isoforms from Agaricus bisporus, was purified to homo...

Pseudomonas putida F6 was found to metabolize p-hydroxyphenylacetic acid through 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxymandelic acid, and 3,4-dihydroxybenzaldehyde. Cell extracts of P. putida F6 catalyze the NAD(P)H-independent hydroxylation of p-hydroxyphenylacetic acid to 3,4-dihydroxyphenylacetic acid which is further oxidized to 3,4-dihydroxymandelic acid. Oxidation and decarboxylati...

General. The effect of shaft currents passing through an oil film in a bearing is to accelerate polymerization and oxidation and cause thermal decomposition. The oil darkens in colour, sometimes increases in acidity, and generally deposits a chocolate-colour precipitate in the oil system. Arcing will also cause small particles of metal to flake off and contaminate the oil. If a shaft current is...

In this research thin film heterogeneous cation exchange membrane was prepared by interfacial polymerization of polyacrylic acid-co-iron nickel oxide nanoparticle son PVC based substrate. Spectra analysis confirmed graft polymerization conclusively. The SEM images showed that polymerized layer covers the membranes by simple gel network entanglement. Results exhibited that membrane water content...

The crystal structure of poly(7-heptalactone) (PHL) is presented. PHL has been synthesized by a combination ring-opening polymerization η-heptalactone and reversible addition–fragmentation chain transfer using diphenyl phosphate as catalyst. noncommercial available monomer prepared oxidation cycloheptanone. determined analysis the X-ray powder diffraction profiles electron patterns single cryst...

Rapid detection of bacterial presence on implantable medical devices is essential to prevent biofilm formation, which consists densely packed bacteria colonies able withstand antibiotic-mediated killing. In this work, a smart approach presented integrate electrochemical sensors for detecting infections in biomedical implants made isotactic polypropylene (i-PP) using chemical assembly. The based...

ethylene was polymerized in slurry phase over a ticl4/mg(oc2h5)2 catalyst activated by al(c2h5)3. it was shown experimentally that mass transfer resistance has no effect on polymerization kinetics. after estimation ofthe active site concentration by inhibition method with carbon monoxide, the effects of polymerization temperature, monomer and cocatalyst  oncentrations and hydrogen were investig...

Background and Aim: Minimizing the polymerization shrinkage of composite resins is a critical goals in composite restorations. Many factors affect polymerization shrinkage. This study aimed to evaluate the effect of composite resin shade on polymerization shrinkage. Materials and Methods: In this in vitro study, 14 composite discs measuring 1.5×8 mm were fabricated. The samples were prepared u...