Electrochemical template synthesis of adherent polyaniline thin films with tubular structure

The synthesis of nano and microstructured thin polyaniline (PANI) films by a simple and very efficient template-assisted method is presented. This work shows the synthesis and characterization of acoustically rigid thin films structured at nanotubular shape by using methyl orange (MO) as a template-assisted system. The amount of the tubes can be easily controlled by the charge passed. The morphology for different films growth was characterized by field emission scanning electron microscopy (FESEM), Atomic force microscopy (AFM), and quartz crystal microbalance with dissipation mode (QCM-D). Raman spectroscopy results show important changes in the conformational PANI chain of the tubular material compare with a non-tubular one that provokes the increase of bipolarons population. This should be responsible by some changes in the electrochemical behavior of tubular film compared with the granular material, due to the higher conductivity when the emeraldine form starts to be formed.     

Insights into the Antimicrobial Activity of Hydrated Cobaltmolybdate Doped with Copper

Molybdates are biocidal materials that can be useful in coating surfaces that are susceptible to contamination and the spread of microorganisms. The aim of this work was to investigate the effects of copper doping of hydrated cobalt molybdate, synthesized by the co-precipitation method, on its antibacterial activity and to elucidate the structural and morphological changes caused by the dopant in the material. The synthesized materials were characterized by PXRD, Fourier Transformed Infrared (FTIR), thermogravimetric analysis/differential scanning calorimetry (TG/DSC), and SEM-Energy Dispersive Spectroscopy (SEM-EDS). The antibacterial response of the materials was verified using the Minimum Inhibitory Concentration (MIC) employing the broth microdilution method. The size of the CoMoO₄·1.03H₂O microparticles gradually increased as the percentage of copper increased, decreasing the energy that is needed to promote the transition from the hydrated to the beta phase and changing the color of material. CoMoO₄·1.03H₂O obtained better bactericidal performance against the tested strains of Staphylococcus aureus (gram-positive) than Escherichia coli (gram-negative). However, an interesting point was that the use of copper as a doping agent for hydrated cobalt molybdate caused an increase of MIC value in the presence of E. coli and S. aureus strains. The study demonstrates the need for caution in the use of copper as a doping material in biocidal matrices, such as cobalt molybdate.     

Determination of Caseinomacropeptide in Brazilian Bovine Milk by High-performance Liquid Chromatography–Mass Spectrometry

Milk adulteration is a concern in many countries, including Brazil. There are many compounds used as adulterants, including cheese whey, a by-product of cheese. Recently, we have developed a proteomic-like technique for separation and characterization of caseinomacropeptide using liquid chromatography coupled to mass spectrometry with electrospray ionization. Caseinomacropeptide is important because it can be used as marker when cheese whey adulteration is performed in bovine milk. Furthermore, it is difficult to establish reference values for caseinomacropeptide levels because of the variation of milk composition. The aim of this study was to verify the average value for caseinomacropeptide present in bovine raw milk collected by Federal Inspection Service from five regions of Brazil (north, northwest, west central, south, southeast). Survey sampling was divided into two stages: first one, a data set 1 (regional sampling) was collected only from the south during a year. This data sampling was used to estimate the data set 2 (national sampling). A largest extreme value was suggested as a model for caseinomacropeptide distributions for national sampling. The data set showed 2.52?mg?L^?1 as the mean and 4.80?mg?L^?1 for the standard deviation based on a sampling size of 170?units collected across Brazil. The findings are useful to understand the presence of caseinomacropeptide, especially when no adulteration or the absence of good practices is present.