Solid State Phenomena Vol. 190

Abstract: There are various methods to shield spacecraft from energetic particles, like one based on the usage of the permanent magnets. At the same time this method is not perfect; it only suggests low intensity magnetic field because of neglecting galactic cosmic radiation effects on human body. In this paper, hyper thin rings as a shield for spacecraft are suggested. Although these rings are lighter than permanent magnets, their ability to protect spaceship with a safe and high intensity magnetic field is higher than the magnets.

Abstract: Citric-ferrite sol (CFS) has been synthesized and successfully tested as MRI negative contrast preparation for revealing primary tumors, and also invasions and metastases at the tumor relapses. Magnetohydrodynamic thermochemotherapy (MTC) by Cysplatin (CP), Mitoxantron (MX), Melphalan (MP) combined with CFS, which were carefully monitoring in vivo and quantified by an electronic detector, improved results of cancer treatment. At various stages of oncogenesis, MTC with CFS at a dose of 62 mg Fe/kg combined with chemotherapeutic drugs was performed at +48º C for 30 min. While such MTC, treatment of ~30 mm3 B 16 melanoma tumor by AC magnetic field led to tumor regression in female mice up to 40 %, and an increase of life span up to 300 % was achieved.

Abstract: Mössbauer investigations of solid phases that were formed during the reduction of amorphous synthesized ferrihydrite (SF) by thermophilic anaerobic iron-reducing bacterium Thermincola ferriacetica (strain Z-0001) and alkaliphilic anaerobic iron-reducing bacterium Geoalkalibacter ferrihydriticus (strain Z-0531) were carried out at room, liquid nitrogen and helium temperatures in the presence or the absence of an external magnetic field (6 T). The magnetization M (T, H) was measured in the temperature interval 80-300 K and magnetic field up to 10 kOe. It was performed zero field cooling (ZFC) and field cooling (FC) measurements of M (T).

Abstract: In order to extract a quantitative information about characteristics of the magnetic nanoparticles injected into a living organism one has to define a model of the magnetic dynamics in order to fit self-consistently the whole set of the experimental data, particularly, the evolution of Mössbauer spectral shape with temperature and external magnetic field as well as the magnetization curves. We have developed such a model and performed such an analysis of the temperature-and magnetic field-dependent spectra and magnetization curves of nanoparticles injected into a mice. This allowed us to reliably evaluate changes in the residual nanoparticles characteristics and their chemical transformation to paramagnetic ferritin-like forms in different mouses organs as a function of time after injection of nanoparticles. Actually, the approach allows one to quantitatively characterize biodegradation and biotransformation of magnetic nanoparticles injected into a body.

Abstract: A process of the biodegradation in vivo of a magnetic ferrofluid was investigated by Mössbauer spectroscopy. After the injection of the ferrofluid in a mice body an additional doublet was observed in the Mössbauer spectra of the mice liver. Further analysis showed that the doublet consists of two components with different magnetic properties. The components related both to the formation of non-magnetic ferritin-like proteins and superparamagnetic behavior of the injected nanoparticles. These components were separated in an external magnetic field and the time evolution of each fraction was studied. The concentration of both of these fractions in the frame of multi-level relaxation model was estimated.

Abstract: Structure, valence and magnetic states of iron ions of the nanodispersed magnetite stabilised by a dielectric matrix have been studied by the ⁵⁷Fe Mössbauer spectroscopy, X - ray and electronic microscopy.

Abstract: Magneto-optical Fraunhofer diffraction on phase 2D domain patterns with Cmm6 and Pab2 symmetry in uniaxial iron garnet films was studied. Domain patterns contain more than 100 elementary cells and have high spatial homogeneity. The diffraction patterns contain up to 10 or more orders of peaks. Possibilities of space-time modulation of optical radiation and multiplication of the modulation frequency both under change of diffraction order as well as amplitude of magnetic bias field strength were shown.