Redox-active nickel in carbon nanotubes and its direct determination

The presence of residual metal-catalyst impurities in carbon nanotubes is responsible for their toxicity. It is important to differentiate between the total amount of impurities and the redox-active (bioavailable) amount of such impurities because only the bioavailable impurities exhibit toxic effects. Herein, we report a simple and specific method for quantifying the amount of redox-active Ni present in various commercial samples of CNTs. It is based on the electrochemical oxidation of Ni(OH)(2) that is formed in alkaline solutions when Ni impurities are opened to the surrounding environment. Metallic Ni impurities play an extremely active role in toxicological assays as well as in undesired catalytic processes, and thus a method to rapidly quantify the amount of redox-active Ni is of great importance.     

Resveratrol-derived stilbenoids and biological activity evaluation of seed extracts of Cenchrus echinatus L

A phytochemical study of the ethyl acetate fractions from the partition of seeds and roots methanol extracts of Cenchrus echinatus L. led to the isolation of three resveratrol-derived stilbenoids: pallidol (1), carasiphenol C (2) and nepalensinol B (3). The results of a topic anti-inflammatory evaluation, DPPH assay and antiproliferative activity against adenocarcinoma cells (Caco 2) are described.     

Mean-field cooperativity in chemical kinetics

We consider cooperative reactions and we study the effects of the interaction strength among the system components on the reaction rate, hence realizing a connection between microscopic and macroscopic observables. Our approach is based on statistical mechanics models and it is developed analytically via mean-field techniques. First of all, we show that, when the coupling strength is set positive, a cooperative behavior naturally emerges from the model; in particular, by means of various cooperative measures previously introduced, we highlight how the degree of cooperativity depends on the interaction strength among components. Furthermore, we introduce a criterion to discriminate between weak and strong cooperativity, based on a measure of “susceptibility.” We also properly extend the model in order to account for multiple attachments phenomena: this is realized by incorporating within the model p-body interactions, whose non-trivial cooperative capability is investigated too.     

Redox‐Active Nickel in Carbon Nanotubes and Its Direct Determination

The presence of residual metal‐catalyst impurities in carbon nanotubes is responsible for their toxicity. It is important to differentiate between the total amount of impurities and the redox‐active (bioavailable) amount of such impurities because only the bioavailable impurities exhibit toxic effects. Herein, we report a simple and specific method for quantifying the amount of redox‐active Ni present in various commercial samples of CNTs. It is based on the electrochemical oxidation of Ni(OH)₂ that is formed in alkaline solutions when Ni impurities are opened to the surrounding environment. Metallic Ni impurities play an extremely active role in toxicological assays as well as in undesired catalytic processes, and thus a method to rapidly quantify the amount of redox‐active Ni is of great importance.     

Introducing dichlorocarbene in graphene

The functionalization of graphene with dichlorocarbene has been successfully attained based on a conventional method for the generation of dichlorocarbenes. The obtained material was fully characterized using high resolution X-ray photoelectron spectroscopy, transmission electron microscopy, infrared and Raman spectroscopies.     

Ytterbium triflate catalysed Meerwein-Ponndorf-Verley (MPV) reduction

Ytterbium triflate was shown to be effective in promoting the reduction of substituted aromatic and aliphatic aldehydes and ketones using isopropanol as the solvent and the reducing agent. The whole process furnished the desired adducts in 22-98% yield.     

Palladium-catalyzed oxidative homocoupling of potassium alkenyltrifluoroborates: synthesis of symmetrical 1,3-dienes

Herein, we describe a convenient method for the synthesis of symmetrical 1,3-dienes employing an oxidative palladium-catalyzed homocoupling of potassium alkenyltrifluoroborates providing products in good yields relative to existing methodologies. This is the first report of a cross-dimerization of potassium alkenyltrifluoroborates.     

Remarks on projectivities

Aequationes mathematicae -