Federal University of São Carlos

About: Federal University of São Carlos is a education organization based out in São Carlos, Brazil. It is known for research contribution in the topics: Population & Microstructure. The organization has 16471 authors who have published 34057 publications receiving 456654 citations. The organization is also known as: UFSCar & Federal University of São Carlos.

Simultaneous determination of paracetamol and levofloxacin using a glassy carbon electrode modified with carbon black, silver nanoparticles and PEDOT:PSS film

Abstract: A new voltammetric sensor is proposed for the simultaneous determination of paracetamol (PAR) and levofloxacin (LEV), using a glassy carbon electrode (GCE) modified with silver nanoparticles (AgNPs), carbon black (CB), and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS). The modification of the electrode surface was performed by drop-casting dispersion. Morphological characterization of the AgNPs-CB-PEDOT:PSS film was performed by scanning electron microscopy and transmission electron microscopy. The electrochemical behaviors of PAR and LEV were evaluated by cyclic voltammetry in a potential range from 0 to 1.2 V, at a scan rate of 0.05 V s −1 . Two oxidation peaks were observed during the anodic potential scanning, at potentials of 0.45 (PAR) and 1.0 V (LEV). Compared to the bare GCE, the anodic peak currents (i pa ) obtained using the AgNPs-CB-PEDOT:PSS/GCE sensor were higher by factors of 5.7 (PAR) and 12 (LEV). The electrochemical determination by square wave voltammetry provided linear concentration ranges of 6.2 × 10 −7 to 7.1 × 10 −6 mol L −1 (PAR) and 6.7 × 10 −7 to 1.2 × 10 −5 mol L −1 (LEV), with detection limits of 1.2 × 10 −8 and 1.4 × 10 −8 mol L −1 for PAR and LEV, respectively. The AgNPs-CB-PEDOT:PSS/GCE sensor showed good stability, reproducibility, and repeatability, and no interference in the electrochemical determination of PAR and LEV in the presence of other compounds. The proposed method was successfully applied using synthetic urine and river water samples, with recoveries close to 100%.

New large grain, highly crystalline, transparent glass-ceramics

Abstract: Two main reasons assure the transparency in the visible of some glass–ceramics (TGC): their crystal sizes are much smaller than the wavelength of light or the difference between the refractive index of glass matrix and crystal phase is small. The majority of traditional TGC have nano-size crystals and small to moderate crystallized volume fraction, usually between 3% and 70%. In this article we present a new type of transparent glass–ceramics having large (micrometric) grain size and very high crystallized volume fraction, which reaches up to 97%. Their high transparency mainly results from simultaneous variations of the glass matrix and crystal compositions during crystallization, which considerably decreases the difference between the respective refractive indexes, and this factor prevails, regardless of crystal size. Preliminary tests of their optical properties indicate that this new family of TGC can be further developed by doping with transition metals and rare-earths.

Resistance spectra of wheat cultivars and virulence diversity of Magnaporthe grisea isolates in Brazil

Abstract: Seventy-two monoconidial isolates of Magnaporthe grisea were obtained from the States of Mato Grosso do Sul and Parana. The isolates were inoculated on seedlings of 20 wheat (Triticum aestivum) cultivars under greenhouse conditions. The virulence diversity of M. grisea was assessed based on compatible and incompatible reactions of leaf blast on wheat cultivars. Fifty-four distinct virulence patterns were identified on test cultivars among the isolates collected from the two wheat growing States. Sixteen of these isolates corresponding to 22.2% showed similar virulence pattern. None of the wheat cultivars was resistant to all isolates of M. grisea, but the cultivars differed in degree of resistance as measured by the relative spectrum of resistance (RSR) and disease index (DI). Among the cultivars the RSR ranged from 0 to 53.3% and DI from 0.4662 to 0.9662 (0 to 1 scale). The wheat cultivar BR18 exhibited a broad resistance spectrum in relation to the rest of the tested cultivars to the isolates of M. grisea, and can be used in wheat resistance breeding.