Search

Herein we present the results of specific loss power (SLP) analysis of polydisperse water based ferrofluids, Fe3O4/PEG200 and Fe3O4/PEG6000, with average Fe3O4 particle size of 9 nm and 11 nm, respectively. Specific loss power was measured in alternating magnetic field of various amplitudes and at fixed frequency of 580.5 kHz. Maximum SLP values acquired were 195 W/g for Fe3O4/PEG200 and 60 W/g for Fe3O4/PEG6000 samples. The samples were labeled as superparamagnetic by magnetization measurements, but SLP field dependence showed deviation from the behavior predicted by the commonly employed linear response theory. The scope of this theory for both samples with wide particle size distribution is discussed. Deviation from the expected behavior is explained by referring to polydisperse nature of the samples and field dependent relaxation rates. [ABSTRACT FROM AUTHOR]

This paper represents the continuation of phonetic-phonological research within the project Research on the Culture and History of the Serbs in Romania, which takes place under the auspices of the Center for Scientific Research and Culture of the Serbs in Romania. It is based on field research conducted during September 2022, in Serbian settlements in the Danube Gorge in Romania (Svinica). The analysis of accent characteristics-the inventory and distribution of prosodes in the speech of Svinica-revealed that it is a specific mixed speech type in which elements of the three-accent system are present, but also the process of simplification and liquidation of tonal oppositions and the appearance of an expiratory accent, which is characteristic of the speeches of Eastern Serbia. The analysis of the linguistic material presented in the paper supports the thesis concerning the autochthonous Serbian population in the Banat Gorge.

We present a study of dynamic magnetic properties of superparamagnetic CoFe2O4 nanoparticles of average size 5.9 nm suspended in an organic liquid. The relaxation times of the particle magnetic moments are found to be strongly dependent on the size of the particles, and also considerably dependent on interparticle interactions. Besides the lower frequency peak, an additional much faster relaxation is observed in the frequency dependence of the imaginary part of the ac magnetic susceptibility below the freezing point of the liquid. It is found that a large contribution to the magnetic relaxation of the lower frequency peak originates from the particles of dimensions 6.3-5.1 nm with interparticle interactions in the range 25-82 K, which correspond to nearer-neighbor particles. Much faster relaxation indicates that its significant part arises from the particles of dimensions 5.8-5.0 nm with interactions in the range 1-52 K which include also more distant neighbors. [ABSTRACT FROM AUTHOR]

α-lithium ferrite (Li0.5Fe2.5O4) nanoparticles have been prepared using two synthesis routes: citrate gel decomposition as well as the Pechini method. Analysis of HRTEM images of the particles showed that they have a core/shell structure, an average size of ∼10 nm and stacking faults parallel to the (110) planes. In both samples, the distribution of the Li and Fe cations was found to be partially ordered on the octahedral sites (Wyckoff positions 4b and 12d of space group P4332). According to literature data, Li0.5Fe2.5O4 should adopt a disordered spinel structure (so called β-phase, space group [formula]) for crystallites of 10 nm or less in size. In this study it is shown that (a) the symmetry of the Li0.5Fe2.5O4 nanoparticles depends on the degree of their crystallinity and (b) the ordered crystal structures can be formed even for crystallites of 5-6 nm in size. By fitting the room temperature Mössbauer spectra it was obtained that the hyperfine field values are lower in the sample synthesized by the Pechini method. The Pechini process probably resulted in larger distortions of the cation environments than the citrate gel decomposition method. The saturation magnetization in turn was higher for the material obtained by the gel decomposition approach. [ABSTRACT FROM AUTHOR]

In this paper we report results of structural, spectroscopic, and magnetic investigations of MgFe2O4 nanoparticles prepared by soft mechanochemical synthesis. MgFe2O4 nanoparticles crystallize in Fd3m space group with mixed cation distribution and reduced percentage of Fe3+ at tetrahedral (8a) sites. Discrepancy in the cation distribution compared to that in the bulk Mg–ferrite is one of the highest known. X-ray line broadening analysis reveals crystallite size and strain anisotropy. The saturation magnetization, Msat=62 emu/g measured at 5 K is twice higher than that found in the bulk counterparts. Such high value of Msat is attributed to the low value of cation inversion parameter (δ=0.69), to the core/shell structure of the nanoparticles and to the surface/volume ratio. Mössbauer spectrum collected at room temperature reveals ferrimagnetic ordering between Fe3+ ions in 8a and 16d sites, while zero-field-cooled (ZFC) and field-cooled (FC) M(T) measurements were shown superparamagnetic state above 350 K. [ABSTRACT FROM AUTHOR]

Several studies are conducted to explain a new approach, which employs the soft mechanochemical route for the synthesis of the nanostructured random type Mg[Fe.sub.2][O.sub.4] spinels. The enhancement of magnetization taking place in the compounds is also analyzed.

Backgrund/Aim. Lafora disease (LD) is progressive myoclonus epilepsy, characterized by intractable myoclonus and seizures, inevitable neurological deterioration, brutal cognitive decline and poor prognosis. The treatment still remains purely symptomatic. Recently, two single-case studies and one case series study reported the favourable effects of perampanel in LD. Our study aimed to test the benefits reported in three separate case studies. Methods. We performed an open label, prospective study of 4 patients aged between 22 and 34 years with mutation in NHLRC1 (EPM2B) gene, treated with perampanel (6–8 mg/day) as add-on therapy. Follow-up period comprised 14–26 months. Seizure frequency, myoclonus, functional disability and cognitive performance were analysed. Results. In 3 patients, both, seizures and myoclonus, showed remarkable improvement after the drug introduction (> 50% reduction). No significant effect was seen in one case. The functional and cognitive impairment maintained at the same level, though all patients were at the later stage of the disease. Psychiatric side effects were dose related. Conclusion. Our study supports the rare, previously reported observations that perampanel is beneficial in treating LD patients.