Bjurböle L/LL4 ordinary chondrite properties studied by Raman spectroscopy, X-ray diffraction, magnetization measurements and Mössbauer spectroscopy.

Bjurböle L/LL4 ordinary chondrite was studied using scanning electron microscopy with energy dispersive spectroscopy, Raman spectroscopy, X-ray diffraction, magnetization measurements and Mössbauer spectroscopy. The phase composition and the relative iron fractions in the iron-bearing phases were determined. The unit cell parameters for olivine, orthopyroxene and clinopyroxene are similar to those observed in the other ordinary chondrites. The higher contents of forsterite and enstatite were detected by Raman spectroscopy. Magnetization measurements showed that the temperature of the ferrimagnetic-paramagnetic phase transition in chromite is around 57 K and the saturation magnetic moment is ~7 emu/g. The values of the 57Fe hyperfine parameters for all components in the Bjurböle Mössbauer spectrum were determined and related to the corresponding iron-bearing phases. The relative iron fractions in Bjurböle and the 57Fe hyperfine parameters of olivine, orthopyroxene and troilite were compared with the data obtained for the selected L and LL ordinary chondrites. The Fe2+ occupancies of the M1 and M2 sites in silicate crystals were determined using both X-ray diffraction and Mössbauer spectroscopy. Then, the temperatures of equilibrium cation distribution were determined, using two independent techniques, for olivine as 666 K and 850 K, respectively, and for orthopyroxene as 958 K and 1136 K, respectively. Implications of X-ray diffraction, magnetization measurements and Mössbauer spectroscopy data for the classification of the studied Bjurböle material indicate its composition being close to the LL group of ordinary chondrites.

Structural and magnetic study of the iron cores in iron(III)-polymaltose pharmaceutical ferritin analogue Ferrifol®.

Iron(III)-polymaltose pharmaceutical ferritin analogue Ferrifol® was investigated by high resolution transmission electron microscopy (HRTEM), X-ray diffraction, thermogravimetry, electron magnetic resonance (EMR) spectroscopy, direct current magnetization measurements and 57Fe Mössbauer spectroscopy to get novel information about the structural arrangement of the iron core. The Ferrifol® Mössbauer spectra measured in the range from 295 K to 90 K demonstrated non-Lorentzian two-peak pattern. These spectra were better fitted using a superposition of 5 quadrupole doublets with the same line width. The obtained Mössbauer parameters were different and an unusual line broadening with temperature decrease was observed. Measurements of the Ferrifol® Mössbauer spectra from 60 K to 20 K demonstrated a slow decrease of magnetic relaxation in the iron core. Zero-field-cooled and field-cooled magnetization measurements revealed a blocking temperature at ~33 K and a paramagnetic state of the Ferrifol® iron core at higher temperatures. Isothermal magnetization measurements at 5 K show that the saturation magnetic moment is ~0.31 emu/g. X-band EMR spectroscopy measurements revealed the presence of different magnetic species in the sample. Transmission electron microscopy demonstrated that the size of the iron cores in Ferrifol® is in the range 2-6 nm. The lattice periodicity in these iron cores, measured on the HRTEM images, vary in the range 2.2-2.7 Å. This can be best understood as sets of close packed O(OH) layers in ferrihydrite cores without long range correlation.

Variability of Chelyabinsk meteoroid stones studied by Mössbauer spectroscopy and X-ray diffraction.

The meter-scale variations of material properties of the 20-m sized Chelyabinsk meteoroid are critical for understanding why the meteoroid fragmented the way it did and caused the devastating airburst that sent over 1600 people to the hospital for treatment of glass cuts and minor injuries on February 15, 2013. From a range of differently looking unweathered meteorite fragments that were recovered shortly after the event, these material differences were probed by means of optical and scanning electron microscopy, X-ray diffraction (XRD), and the high velocity resolution Mössbauer spectroscopy. All main and some minor iron-bearing phases were identified on the basis of XRD data and Mössbauer spectra. The Fe2+ partitioning between the M1 and M2 sites in silicate phases was determined independently using XRD and Mössbauer data. Different meteorite fragments show a range of 570-1180 K in the temperature of the Fe2+ and Mg2+ equilibrium distribution between the M1 and M2 sites in olivine, while that in orthopyroxene falls in the range 870-1180 K (these ranges were estimated using both techniques). This fact points out a slightly different thermal history of these minerals before they accumulated in different parts of the Chelyabinsk meteoroid. The Chelyabinsk meteoroid is a fragmental breccia from materials formed at different depths in their parent body, or from materials that experienced different annealing temperatures in impacts. In addition, the fusion crust from two fragments, studied by XRD and Mössbauer spectroscopy, experienced a different thermal history during entry, suggesting that the fragment with mixed light and dark lithologies was located deeper inside the initial meteoroid than the fragment with only light lithology, or fragmented less readily.

The Iron State in Spleen and Liver Tissues from Patients with Hematological Malignancies Studied Using Magnetization Measurements and Mössbauer Spectroscopy.

In this overview, we present the results of the study of spleen and liver tissues taken from healthy donors in comparison with those from patients with (i) non-Hodgkin B-cell lymphomas, namely, mantle cell lymphoma and marginal zone B-cell lymphoma, (ii) acute myeloid leukemia, and (iii) primary myelofibrosis. The study was carried out using Mössbauer spectroscopy and magnetization measurements for the analysis of ferritin-like iron in spleen and liver tissues. Magnetization measurements demonstrated small differences in the saturation magnetic moments and revealed additional paramagnetic components. Two liver samples demonstrated unusual behavior of the magnetic moment when the zero-field-cooled curve was over the field-cooled curve in the temperature range between ~40 and ~70 K. Relative iron content variations in the tissue cells as well as small variations in the 57Fe hyperfine parameters were demonstrated for healthy and patients' spleen and liver tissues on the base of measured Mössbauer spectra. The results obtained permit us to suggest small differences in the ferritin iron core structure in spleen and liver tissues from healthy donors and patients with hematological malignancies.

Different 57Fe microenvironments in the nanosized iron cores in human liver ferritin and its pharmaceutical analogues on the basis of temperature dependent Mössbauer spectroscopy.

Mössbauer spectra of human liver ferritin and its pharmaceutical analogues Ferrum Lek and Maltofer® measured at various temperatures within the range of 295-83K were fitted using five quadrupole doublets related to different 57Fe microenvironments in various layers/regions of the ferrihydrite and akaganéite iron cores. The observed anomalous temperature dependences of some Mössbauer parameters were considered as a result of low temperature structural rearrangements in different layers/regions in the iron core.

57Fe Mössbauer spectroscopy and electron paramagnetic resonance studies of human liver ferritin, Ferrum Lek and Maltofer®.

A human liver ferritin, commercial Ferrum Lek and Maltofer® samples were studied using Mössbauer spectroscopy and electron paramagnetic resonance. Two Mössbauer spectrometers have been used: (i) a high velocity resolution (4096 channels) at 90 and 295K, (ii) and a low velocity resolution (250 channels) at 20 and 40 K. It is shown that the three studied materials have different superparamagnetic features at various temperatures. This may be caused by different magnetic anisotropy energy barriers, sizes (volume), structures and compositions of the iron cores. The electron paramagnetic resonance spectra of the ferritin, Ferrum Lek and Maltofer® were decomposed into multiple spectral components demonstrating the presence of minor ferro- or ferrimagnetic phases along with revealing marked differences among the studied substances. Mössbauer spectroscopy provides evidences on several components in the measured spectra which could be related to different regions, layers, nanocrystallites, etc. in the iron cores that coincides with heterogeneous and multiphase models for the ferritin iron cores.

Mössbauer spectroscopy of the iron cores in human liver ferritin, ferritin in normal human spleen and ferritin in spleen from patient with primary myelofibrosis: preliminary results of comparative analysis.

Comparative study of human liver ferritin and spleen tissues from healthy human and patient with primary myelofibrosis was carried out using Mössbauer spectroscopy with a high velocity resolution at 295 and 90 K and with a low velocity resolution at 20 K. The results obtained demonstrated that the iron content in patient's spleen in the form of iron storage proteins was about ten times larger than that in normal tissue. However, in the case of patient with primary myelofibrosis the magnetic anisotropy energy barrier differed from that in normal case and, probably, the iron core size was supposed to be slightly larger than that in both normal spleen tissue and normal human liver ferritin in contrast to well-known data for iron overload in patients with thalassemia accompanied by the iron-core size increase. Therefore, the iron overload in the case of patient with primary myelofibrosis may be related to increase in the ferritin content mainly. It was also found that Mössbauer hyperfine parameters for normal and patient's spleen and normal human liver ferritin demonstrated some small differences related, probably, to some small structural variations in the ferritin iron cores of patient's spleen.

[Preparation and spectroscopic studies of diorganotin(IV) complexes with adenosine and related compounds]. / Az adenozin és rokonvegyületei di-n-butilón(IV) komplexeinek elóállítása és spektroszkópiás vizsgálata.

Nine complexes of adenosine and related compounds (adenosine-5'-monophosphate, adenosine-5'-triphosphate, 1-methyl-adenosine, pyridoxal-5-phosphate and beta-nicotinamide-adenine-dinucleotide-phosphoric acid) with di-n-butyltin(IV) oxide and/or di-n-butytin(IV) dichloride were prepared in the solid state. The compositions of the complexes were determined by standard analytical methods. It was found that the complexes contain organotin(IV) moiety and the ligand in a ratio of 1:1 or 2:1. The FTIR spectra demonstrated that di-n-butyltin(IV) oxide reacts with the D-ribose moiety of the ligands, while di-n-butyltin(IV) dichloride is co-ordinated to the deprotonated phosphate group. The basic part of the ligands does not participate directly in complex formation. Comparison of the experimental Mössbauer delta E values with those calculated on the basis of the PQS concept revealed that the organotin(IV) moiety has trigonal-bipyramidal, octahedral and in some cases tetrahedral geometry also. Some of the complexes contain the organotin(IV) cation in two different surroundings.

[Unusual coordination behavior of D-fructose towards dimethyltin(IV)2+: metal-promoted deprotonation of alcoholic hydroxyl groups in aqueous solutions at low pH]. / A D-fruktóz szokatlan viselkedése dimetilón(IV)2+ kation jelenlétében: az alkoholos hidroxilcsoport fémion által indukált deprotonálódása vizes közegben, alacsony pH-n.

To study the effect of the conformation of sugar hydroxy groups on metal complexation processes, complex formation of eight saccharides (D-fructose, L-sorbose, L-arabinose, D-arabinose, D-glucose, D-sorbitol, 2-deoxy-D-glucose and D-saccharose) with dimethyltin(IV)2+ cations was investigated in aqueous solution by potentiometric equilibrium measurements, 13C NMR, polarimetric and Mössbauer spectroscopic methods. The experimental results proved that deprotonation of D-fructose and L-sorbose is caused by the coordination of dimethyltin(IV)2+ in the unusual low pH interval 4-6 in contrast to the other saccharides deprotonated in analogous way at pH > 8. Increasing the pH of the solution resulted in the formation of further complexes. Stability and composition of the species was determined by potentiometric studies. 13C NMR measurements led to the assignment of the sugar OH groups participating in the processes. Mössbauer investigations in the quick-frozen solutions permitted the determination of the stereochemistry of tin(IV) in the complexes.

Mössbauer spectroscopic study of the interaction of indole-3-acetic acid with iron(III) in aqueous solution.

The data of Mössbauer spectroscopic measurements in rapidly frozen 57FeIII nitrate solutions containing indole-3-acetic acid (IAA) are presented. The results obtained provide direct evidence that iron(III) is gradually reduced by IAA with the formation of soluble iron(II) complex. It has been found that further drying of the solution in air results in complete re-oxidation of iron(II) with the formation of iron(III) complex. The structure of the complexes obtained and their possible role in solubilization and transformation of iron species in soil in the presence of IAA secreted by soil microorganisms into the environment are also discussed.