Toxicity of silver nanoparticles on different tissues in adult Danio rerio.

Although silver nanoparticles (AgNP) are among the most studied nanomaterials by virtue of their broad application in many areas, little is known about their overall toxicity to aquatic organisms after their contamination of the water environment. This study aimed to analyze the effect of the exposure (96 h) to different AgNP concentrations on Danio rerio (zebrafish) tissues. AgNP were synthesized and characterized by transmission electron microscopy (TEM), showing spherical AgNP of 30.00 ± 16.80 nm size. The effects of different AgNP concentrations (1, 3, and 5 µg L-1) on brain, muscle, gill, and liver tissues of zebrafish were investigated. The results show a significant decrease in brain and muscle acetylcholinesterase (AChE) activity. Liver and gill catalase (CAT) activity also decreased significantly. At the highest exposure concentration, muscle AChE was more inhibited (37.3%) than brain AChE (26.4%) and gill CAT was more inhibited (67.4%) than liver CAT (51.2%). D. rerio also showed gill morphological changes such as fusion of secondary lamellae, curvature, dilated marginal channel, and epithelial lifting. This study indicates that gill CAT together with morphological studies are potential biomarkers for AgNP.

Effect of whitening gels on the surface roughness of restorative materials in situ.

Peroxide gels are effective in changing tooth colour but their effect on restorative materials has been poorly studied. The purpose of this investigation was to assess the impact of a commercially available whitening gel containing hydrogen peroxide and a sodium percarbonate formulation on the surface of restorative materials. A total of 12 subjects participated in a double-blinded crossover study. Each wore an intra-oral appliance containing five bovine enamel blocks restored with amalgam, posterior composite, microfilled composite, glass ionomer cement and porcelain. Appliances were worn continuously for 14 days and whitening products were applied twice daily. After 14 days the appliances were removed and values for roughness (R(a)) were obtained using atomic force microscopy. Mean values of R(a) were assessed between baseline and 14 days, and although minor variations were seen, there were no statistically significant differences detected for any material or any whitening product.

Synthesis and spectroscopic characterization of a fluorescent pyrrole derivative containing electron acceptor and donor groups.

The synthesis and fluorescence characterization of a new pyrrole derivative (PyPDG) containing the electron donor-acceptor dansyl substituent is reported. The effects of temperature and solvent polarity on the steady-state fluorescence of this compound are investigated. Our results show that PyPDG exhibits desirable fluorescent properties which makes it a promising candidate to be used as the photoactive material in optical thermometry and thermography applications. Further, the electrochemical and emission properties of polymeric films obtained from the oxidation polymerization of PyPDG are also analyzed.

Effects of UV irradiation on the wettability of chitosan films containing dansyl derivatives.

The morphological and wetting properties of chitosan films containing dansyl derivatives have been investigated. By means of dynamic contact angle measurements, we study the modification of surface properties of chitosan-based films due to UV irradiation. The results were analyzed in the light of the molecular-kinetic theory which describes the wetting phenomena in terms of the statistical dynamics for the displacement of liquid molecules in a solid substrate. Our results show that the immobilization of dansyl groups in the chitosan backbone leads to a pronounced enhancement of the UV sensitivity of polymeric films.

Padronização da técnica de plasmaférese automatizada em equinos / Standardization of automated plasmapheresis in horses

O presente artigo objetivou estudar a viabilidade da técnica de plasmaférese automatizada e padronizá-la em cinco equinos hígidos, bem como apresentar as complicações durante o procedimento, as adequações em relação aos procedimentos em humanos e avaliar a recuperação de volume globular e proteínas plasmáticas totais nos doadores. Os procedimentos foram realizados com o equipamento Fresenius AS104, com duração média de 1h46min, processamento de 5758mL de sangue total e colheita média de 3133mL de plasma. Não foram observadas alterações significativas do volume globular após a plasmaférese automatizada. A recuperação dos níveis plasmáticos de proteínas foi de 91,4% em 96 horas após o procedimento. A plasmaférese automatizada apresentou-se viável para a espécie equina, diminuindo o tempo de recuperação hematimétrica nos doadores.

This paper aimed to study feasibility and standardize the automated plasmapheresis in five healthy horses, showing the complications during the procedure, adjustments in relation to the procedures in humans and assessing the recovery of globular volume and plasma total proteins in donors. The procedures were performed with the Fresenius AS104 equipment, with an average duration of one hour and forty six minutes, processing 5758mL of whole blood and harvest average of 3133mL of plasma. There were no significant variations in globular volume after the automated plasmapheresis. The recovery of plasma total proteins was 91.4% at 96 hours after the procedure. The automated plasmapheresis appeared viable for the equine species, decreasing the time of hematimetric level recovery in donors.