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[Display omitted] Electric and magnetic properties in the frequency range (500 Hz − 2 MHz) of a composite consisting of silicone rubber and ferrofluid with magnetite particles, in a mass ratio 1/20, were investigated. Structural analysis of nanoparticles within the ferrofluid (FM sample) was performed by XRD diffraction and morphology of composite (SR-FM sample), was investigated by SEM analysis. The frequency dependence of the imaginary component, μ″, of complex magnetic permeability of composite sample exhibits two maxima. These have been associated with the Brownian relaxation process within the ferrofluid drops remained in vesicles of silicone rubber. At the same time, a dielectric relaxation process attributed to the Schwarz relaxation was also highlighted. The mechanical mobility, u , of the charge carriers, u = 1.5∙108 m/sN , from the composite sample, was computed. Based on the complex impedance measurements, the frequency dependence of the conductivity, σ(f), was determined, which respects the Jonscher universal law. The static conductivity, σ dc = 2.38∙10-7 S/m, of composite sample, was determined. The results allowed the evaluation of the energy barrier of electrical conduction process, Wm = 0.353 eV and the crossover frequency, ω c = 3.39∙105 rad/s, for composite sample. The performed study is useful in manufacturing magnetic elastomeric composite materials with predetermined properties and for possible technological and biomedical applications. [ABSTRACT FROM AUTHOR]

CuMnO2nanoparticles were obtained for the first time by sonochemical synthesis in an aqueous solution of sodium hydroxide containing soluble copper and manganese nitrate reactants without any further thermal treatment. Experiments were performed at different lengths of time (20 min, 30 and 40 min) and ultrasound amplitude of 80%. The materials present the expected crednerite structure (C2/m space group), and the nanoparticles average size and morphology for each sample are studied by nanoparticle tracking analysis method, respectively, by transmission electron microscopy. The as-obtained materials display p-type semiconductivity behavior at room temperature and the value for direct optical band gap EGis estimated to be approximately ~ 3.6 eV. The study of the magnetic properties for the nanocrystalline crednerite samples reveals 2D magnetic behavior below 110 K and a weak ferromagnetic component at ~ 20 K.

The aim of the present study was to formulate new variants of synthetic and animal-source bone materials coated with different biopolymers, containing antibiotics (ampicillin and oxacillin) and alendronate drugs. Validation consists in establishing mixtures that do not present interactions between components. These materials should act as a drug delivery system alongside the bone base. Natural polymers such as chitosan, alginate, and kappa-carrageenan have been shown to be optimal materials for drug delivery due to their intrinsic biocompatibility. Binary, ternary, and quaternary mixtures between components are analyzed by FT-IR spectroscopy, UV-Vis analysis, thermogravimetry (TGA), and scanning electron microscopy (SEM). The analysis led to the validation of materials suitable for the controlled release of active substances, which have the greatest chance of increasing the speed of bone regeneration, as well as helping in the local administration of antibiotics, which currently must be administered in the form of oral formulations or an injection. According to the FTIR, thermogravimetry, UV-Vis, SEM, and cytotoxicity tests performed in this study, it can be said that it is quite easy to obtain materials that can be used in dental practice that facilitate bone reconstruction through local treatment. At the same time, it was found that both active substances can be incorporated into the material together with Alg and Chit, thus limiting the adverse effects and maximizing the local beneficial effects.

Perovskite-type oxides of LaMnO3were synthesized by means of the sol–gel method, in the presence of citric acid as gelling agent. The precursors used were Mn(NO3)2·H2O, La2O3, and NaOH, mixed in the stoichiometric ratio to obtain perovskite materials. The obtained gel was heat-treated at 400, 600 and 800 °C respectively, for 6 h. X-ray diffraction and FT-IR spectroscopy were used to analyze the phase transformation as a function of temperature, and the Rietveld refinement was used in order to characterize the materials obtained structurally. The average crystallite size of the products was calculated from XRD data and the average particle size was measured from the TEM micrographs. At 600 °C, the synthesized compound is well-crystallized, showcases a perovskite structure (Pm-3mspace group), and exhibits uniform and homogeneous hexagonally-shaped particles, with sizes in the 20–50 nm range. Complex impedance measurements in the 20–2 × 106Hz frequency range were carried out at different temperatures (26–115 °C), and the electrical conduction mechanism is discussed.