Energy dispersive X-ray analysis on supported metallic clusters generated by redox processes on graphite intercalation compounds

Two types of reactions, the reduction of NiBr₂ with KC₈ in THF at room temperature and the reduction of CuCl₂—NiCl₂—GIC with potassium vapor at 300°C, were carried out in order to obtain fine metallic particles supported on the graphite matrix. The reaction products were analyzed by using XRD, SEM, and EDS. In the first reaction, EDS analysis showed that the elements of K, Br and Ni locate mainly on the surface of the graphite flakes, while XRD showed the chemical form of these elements to be metallic Ni and KBr. KBr as a by-product was easily removed by washing with aqueous medium. In the second reaction, on the other hand, EDS spectra showed that a large amount of K and Cl exist on the surface of the as-prepared sample, while almost no metallic elements, such as Ni and Cu, were found on the surface. Even after washing with 2N HCl, KCl was still identified by EDS and XRD, although the relative intensities of Ni and Cu lines in the EDS spectrum increased. It was concluded that most of the reaction products Ni, Cu and KCl are included in the graphite matrix.     

Preventive antioxidant effects of cocoa polyphenolic extract on free radical production and cognitive performances after heat exposure in Wistar rats

ABSTRACT:  The preventive effects of ACTICOA powder (AP), a cocoa polyphenolic extract, on free radicals produced by leucocytes in rats after heat exposure (HE) and its protective effects on subsequent cognitive impairments were assessed. AP or vitamin E, the antioxidant reference, was orally administered to rats for 14 d before HE at 40 °C temperature during 2 h. The day after HE, free radical production by leucocytes in rats treated with AP or vitamin E was significantly reduced as compared to control. Unlike controls, AP- and vitamin E-treated rats discriminated between active lever and inactive levers in a light extinction paradigm. In the Morris water maze, escape latencies before reaching the hidden platform by AP- and vitamin E-treated rats decreased throughout testing. The daily oral administration of AP or vitamin E protected rats from cognitive impairments after HE by counteracting the overproduction of free radicals.