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The iron diet supplements: AproFER 1000 and AproTHEM were subjected to various chemical, microbial and magnetic analysis. The microbial analysis revealed no presence of pathogenic bacteria in the studied products. No significant changes in iron content or forms (bivalent/trivalent) were observed in EPR analysis of supplements stored at different conditions for a long period of time. The chemical and magnetic analysis showed that both AproFER 1000 and AproTHEM contain a high concentration of bivalent iron so they can be used as an iron diet supplements.

The present paper deals with the synthesis and characterization of ZnO nanoparticles obtained by coprecipitation method at three different pH conditions. Samples characterizations aimed at understanding their spectroscopic properties are carried out using a variety of experimental techniques. X-ray diffraction and transmission electron microscopic studies show significant increase in the particle size of the synthesized ZnO nanoparticles ranging from 3–40 nm with increasing pH values. Absorption spectra show particle size dependent blueshift in the energy band, which may be ascribed to quantum confinement effect. Fourier transform infrared (FTIR) spectroscopy reveals enhancement in the surface defects of the synthesized ZnO nanoparticles with increasing pH values. Electron paramagnetic resonance studies at room temperature (300 K) and several liquid helium temperatures (including the lowest temperature 13 K for all samples) indicate the presence of singly ionized oxygen vacancy defects (VO+) and O2- superoxide ions in the ZnO nanoparticles. These results are well supported by FTIR and photoluminescence spectroscopy. The emissions from these nanoparticles are also found to be size dependent, whereas the ratio of UV emission to oxygen vacancy related green emission is found to increase with increasing pH values. Furthermore, a plausible mechanism of the observed defect mediated green emission is proposed. [ABSTRACT FROM AUTHOR]

Nanocomposites of Fe3O4 nanoparticles (NPs) impregnated with silver NPs display antibacterial properties and may be used in water treatment as disinfection agent. Three samples were synthesized: Fe3O4 NPs obtained by the precipitation method and additionally two samples with added silver NPs with mass ratio of Ag:Fe3O4 equal to 1:100 and 2:100. Magnetic properties of these samples were studied by SQUID magnetometry (in temperature range 2–300 K and magnetic fields up to 70 kG) and magnetic resonance technique at RT. Temperature dependence of dc susceptibility revealed the blocking temperature close to RT in all three samples and allowed to determine the presence of single or multi-mode distribution of NP sizes in a particular sample. Isothermal magnetisation measurements showed that the presence of silver NPs, especially those with smaller sizes, decreases the saturation magnetisation. The shape of ferromagnetic loop registered at T = 2 K was used to discuss the sizes of NP magnetic clusters in our samples. Conclusions obtained from analysis of the ferromagnetic resonance spectra were consistent with the propositions based on the magnetometric studies. [ABSTRACT FROM AUTHOR]

Abstract: The electronic structure of N-TiO2 samples prepared by a sol-gel method was investigated by EPR (Electronic Paramagnetic Resonance) measurements and the energy-resolved distribution of electron traps. In EPR spectra, some of the resonance lines assigned to paramagnetic species of nitrogen and Ti3+ were detected. Sample prepared at 300 °C revealed the highest intensity line of the nitrogen paramagnetic centers, whereas that prepared at 400 °C showed a paramagnetic line for Ti3+. Measurements of the electron trap distribution showed higher density of electron traps for sample prepared at 400 °C than that at 300 °C. Sample prepared at 300 °C, which revealed the highest amount of nitrogen built in the titania in the interstitial position was the most active under visible light. It was evidenced that photocatalytic decomposition of acetaldehyde was dependent strongly on the BET surface area and electrokinetic potential of the photocatalyst surface. The UV content in the fluorescent lamp affected the yield of acetaldehyde decomposition. [ABSTRACT FROM AUTHOR]

The (nCo,N)-TiO2 (n = 1, 5 and 10 wt.% of Co) nanocomposites were investigated by magnetic resonance spectroscopy in 4 K to 290 K range. Analyses of ferromagnetic/electron paramagnetic resonance (FMR/EPR) spectra in terms of four Callen lineshape components revealed the existence of two types of magnetic centers, one derived from metallic cobalt nanoparticles in superparamagnetic (SPM) phase and the other from cobalt clusters in the TiO2 lattice. Additionally, at low temperature the EPR spectrum arising from Ti3+ ions was also registered. Both relaxations of the Landau-Lifshitz type and the Bloch-Bloembergen type played an important role at high temperature in determining the linewidths and the latter relaxation was prevailing at low temperature. Analysis of the integrated intensity showed that the SPM signal is due to small size FM cobalt nanoparticles while the paramagnetic signal from Co clusters originates from those nanoparticles in which the concentration of magnetic polarons is below the percolation threshold. [ABSTRACT FROM AUTHOR]

Magnetic properties of 0.7(Fe2O3)/0.3(ZnO) nanocomposite synthesized by traditional wet chemistry method and containing only two phases: ZnO (nonmagnetic) and ZnFe2O4 (magnetic, with nanocrystallites of average size 12 nm, but forming large agglomerates, up to 100 nm in size) were studied by DC magnetization and ferromagnetic resonance (FMR). The investigated nanocomposite was either in a form of nanopowder or dispersed at concentration of 0.1 wt.% in poly(ethylene naphthalate-block-tetramethylene oxide) PTMO-b-PEN polymer matrix. Similarities and differences in magnetic behavior of these two samples revealed by the study of static magnetization and FMR spectra have been discussed relative to different morphologies and the associated variation of interparticle interactions. Moreover, thermal and thermo-oxidative stability of the nanocomposite and the neat polymer have been studied by thermogravimetric method. [ABSTRACT FROM AUTHOR]

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A method of the hydrothermal synthesis of Fe3+-doped titanate nanotubes (TNT) is reported in which the ultra-small Fe3O4 nanoparticles are used as the sources of Fe3+ ions. The magnetic nanoparticles with a diameter of about 2 nm are added during the washing stage of the hydrothermal procedure. During washing, they gradually degrade and at the same time, the titanate product is transformed into nanotubes. The obtained nanotubes were characterized by structural and magnetic measurements. It was found that, depending on the value of the external magnetic field, they may show the property of room temperature ferromagnetism, paramagnetism or they may be diamagnetic. It was also shown that the modified TNTs have greater photocatalytic activity compared to unmodified TNTs. [ABSTRACT FROM AUTHOR]

Thermoplastic elastomeric nanocomposites based on poly(trimethylene terephthalate‐block‐poly(tetramethylene oxide) copolymer (PTT‐PTMO) and graphene oxide (GO)–Fe3O4 nanoparticles hybrid are prepared by in situ polymerization. Superparamagnetic GO–Fe3O4 hybrid nanoparticles before introducing to elastomeric matrix are characterized by X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The effect of loading (0.3 and 0.5 wt%) of GO–Fe3O4 nanoparticle hybrid on the phase structure, tensile, and magnetic properties of synthesized nanocomposites is investigated. The phase structure of nanocomposites is evaluated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). Dispersion of GO–Fe3O4 nanoparticles in elastomeric matrix is evaluated by transmission electron microscopy (TEM). Magnetic properties of GO–Fe3O4 nanoparticle hybrid and nanocomposites with their content are characterized using two different techniques: direct current superconducting quantum interference device (dc SQUID) magnetization measurements as a function of temperature (from 2 to 300 K) and external magnetic field and ferromagnetic resonance (FMR) at microwave frequency. [ABSTRACT FROM AUTHOR]

Magnetic properties of the lyonsite-type phase, Cu3.9Fe3.4V6O24, that has been synthesized by a standard solid-state reaction method, were investigated by dc magnetization and electron paramagnetic resonance (EPR) techniques. Complex magnetic behavior and transition to the antiferromagnetic phase at liquid helium temperature have been revealed by measurements of dc susceptibility in ZFC and FC modes in the 2-300 K temperature range as well as static magnetization in magnetic fields up to 70 kOe. Strong antiferromagnetic interactions in clusters or chains of magnetic ions even at high temperatures has been deduced from the obtained value of the effective magnetic moment that was significantly smaller than expected for nominal valences of iron and copper ions. The presence of antiferromagnetic iron dimers in the high-temperature range, critical slowing down of spin fluctuations on approaching Neel temperature and the existence of magnetically isolated iron ions in the antiferromagnetic phase has been suggested from the temperature dependence of EPR parameters (g-factor, linewidth, integrated intensity) obtained by fitting the experimental spectrum with Lorentzian lineshape. [ABSTRACT FROM AUTHOR]

Nanocomposites based on nanocrystalline titania modified with graphene-related materials (reduced and oxidized form of graphene) showed the existence of magnetic agglomerates. All parameters of magnetic resonance spectra strongly depended on the materials' modification processes. The reduction of graphene oxide significantly increased the number of magnetic moments, which caused crucial changes in the reorientation and relaxation processes. At room temperature, a wide resonance line dominated for all nanocomposites studied and in some cases, a narrow resonance line derived from the conduction electrons. Some nanocomposites (samples of titania modified with graphene oxide, prepared with the addition of water or butan-1-ol) showed a single domain magnetic (ferromagnetic) arrangement, and others (samples of titania modified with reduced graphene oxide) exhibited magnetic anisotropy. In addition, the spectra of EPR from free radicals were observed for all samples at the temperature of 4 K. The magnetic resonance imaging methods enable the capturing of even a small number of localized magnetic moments, which significantly affects the physicochemical properties of the materials.