National Nuclear Energy Commission

About: National Nuclear Energy Commission is a government organization based out in Rio de Janeiro, Brazil. It is known for research contribution in the topics: Dosimetry & Laser. The organization has 3816 authors who have published 4694 publications receiving 59951 citations.

Preconcentration method for the determination of thorium in natural water by wavelength dispersive X-ray fluorescence spectrometry

Abstract: The preconcentration of thorium from natural water and its determination directly by wavelength dispersive X-ray fluorescence spectrometry (WDXRF) were attempted. The first step consists of thorium preconcentration from slightly acid solutions on polyurethane foam (PUF) loaded with 2-etilhexylphosphonic acid (EHPA) reagent as solid phase. PUF held up to 50% (w/w) of the reagent and the preconcentration was maximum at the acidity of 0.25 mol.l-1 hydrochloric solution. Sorption on PUF had fast kinetics and 4.0 and 10 mg.l-1 detection and quantitation limits of thorium were achieved, respectively, as well as a R.S.D. of 4.2% at 21.7 mg.l-1. This method was successfully applied to natural water analyses. The results were in good agreement with reference values of water samples at 95% confidence level.

Electrochemical and in situ ATR-FTIR studies of ethanol electro-oxidation in alkaline medium using PtRh/C electrocatalysts

Abstract: Pt/C, Rh/C and PtRh/C electrocatalysts with different Pt:Rh atomic ratios supported on Vulcan XC 72 carbon were prepared using borohydride as reducing agent and tested for ethanol electro-oxidation in alkaline medium. X-ray diffraction patterns showed the formation of PtRh alloy. Transmission electron micrographs showed the nanoparticles with particle sizes between 3 and 6 nm for all materials. Electrochemical experiments showed PtRh/C (50:50) the most promising material for ethanol electro-oxidation; however, in situ ATR-FTIR experiments was observed that the ethanol oxidation is incomplete due to the formation of acetate and carbonate.

Cytotoxic effects of mistletoe (Viscum album L.) in head and neck squamous cell carcinoma cell lines.

Abstract: Head and neck squamous cell carcinoma is a complex disease with several etiologic factors and different molecular changes that may trigger certain events; it is also globally one of the most common malignancies in this topography. Extracts from Viscum album L. (VA) (mistletoe) have been used as adjuvant therapies with promising results in several types of cancer, mainly in European countries. In vitro studies have demonstrated that various types of VA may have cytotoxicity in carcinoma cells, activating the apoptotic cascade or leading cells to necrosis. This study aimed to verify the effects of three types of VA extracts (Iscador Qu Spezial, Iscador P and Iscador M) in squamous cell carcinoma of the tongue cell lines SCC9 and SCC25, not previously studied. A concentration of 0.3 mg/ml (IC50) of the drugs induced apoptosis, affecting gene expression and protein levels of AKT, PTEN and CYCLIN D1. It was concluded that VA extracts have a cytotoxic effect on SCC9 and SCC25 cell lines, but while SCC9 cell line was more resistant to the action of the drugs, Iscador Qu Spezial and Iscador M have higher cytotoxic potential in both cell lines compared to Iscador P.