The interior and the fusion crust in Sariçiçek howardite: Study using X-ray diffraction, magnetization measurements and Mössbauer spectroscopy.

The meteorite Sariçiçek, a 2015 howardite fall in Turkey, was analyzed using various physical techniques. Both the interior and the fusion crust were studied by optical and scanning electron microscopy with energy dispersive spectroscopy, X-ray diffraction, magnetization measurements and Mössbauer spectroscopy. The main and minor iron-bearing phases such as orthopyroxene, Ca-poor and Ca-rich clinopyroxene, chromite with hercynite, Fe2+ and Fe3+ ilmenite, troilite, α-Fe(Ni, Co), α2-Fe(Ni, Co) and γ-Fe(Ni, Co) phases were identified. The ratios of Fe2+ occupancies in the M1 and M2 sites in the silicate phases as well as the equilibrium Fe2+ and Mg2+ cations distribution temperatures (Teq) for orthopyroxene were estimated using X-ray diffraction and Mössbauer spectroscopy, which appeared to be in a good agreement: for example, Teq were 886 and 878 K, respectively. The glass-like fusion crust of Sariçiçek consists of orthopyroxene with ferrous and ferric compounds that are likely products of combustion and melting.

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.

Characterization of Northwest Africa 6286 and 7857 ordinary chondrites using X-ray diffraction, magnetization measurements and Mössbauer spectroscopy.

Northwest Africa (NWA) 6286 and 7857 meteorites were studied in detail by using optical microscopy, scanning electron microscopy with energy dispersion spectroscopy, X-ray diffraction, magnetization measurements and 57Fe Mössbauer spectroscopy with a high velocity resolution. The main and the minor iron-bearing phases were identified in both meteorites. The unit cell parameters as well as Fe2+ and Mg2+ cation distribution were determined for the M1 and M2 sites in silicate microcrystals. Saturation magnetic moments were obtained for both meteorites. Mössbauer parameters for the main and the minor iron-bearing microcrystals were estimated and compared for NWA 6286 and NWA 7857 LL6 ordinary chondrites. The Fe2+ and Mg2+ cation partitioning, distribution coefficient and temperature of cation equilibrium distribution were estimated for silicate microcrystals using X-ray diffraction and Mössbauer spectroscopy.

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.

Comparison of iron-bearing minerals in ordinary chondrites from H, L and LL groups using Mössbauer spectroscopy with a high velocity resolution.

Ordinary chondrites from H, L and LL groups were studied using Mössbauer spectroscopy with a high velocity resolution. Mössbauer parameters of spectral components were obtained using new fitting model excluding the effect of previous misfits of troilite component. Obtained parameters were related to corresponding iron-bearing minerals in ordinary chondrites. The differences of these minerals content as well as small differences in the hyperfine parameters of the same iron-bearing minerals were revealed for different meteorites. The temperatures of equilibrium cations distribution in silicates were estimated and suitable parameters for classification of H, L and LL chondrites were supposed using Mössbauer parameters.

Study of Iron oxide nanoparticles using Mössbauer spectroscopy with a high velocity resolution.

Iron oxide (magnetite and maghemite) nanoparticles developed for magnetic fluids were studied using Mössbauer spectroscopy with a high velocity resolution at 295 and 90K. The recorded Mössbauer spectra have demonstrated that usual physical models based on octahedral and tetrahedral sites were not suitable for fitting. Alternatively, the Mössbauer spectra were nicely fitted using a large number of magnetic sextets. The obtained results showed that the Mössbauer spectra and the assessed parameters were different for nanoparticles as-prepared and dispersed in the dispersing fluid at 295K. We claim that this finding is mainly due to the interaction of polar molecules with Iron cations at nanoparticle's surface or due to the surface coating using carboxylic-terminated molecules. It is assumed that the large number of spectral components may be related to complexity of the nanoparticle's characteristics and deviations from stoichiometry, including in the latter the influence of the oxidation of magnetite towards maghemite.

Evaluation of the Debye temperature for iron cores in human liver ferritin and its pharmaceutical analogue, Ferrum Lek, using Mössbauer spectroscopy.

An iron-polymaltose complex, Ferrum Lek, used as antianemic drug and considered as a ferritin analogue and human liver ferritin were investigated in the temperature range of 295-90K using (57)Fe Mössbauer spectroscopy with a high velocity resolution (in 4096 channels). This study aimed to make a comparison of the Fe atom dynamics in the Ferrum Lek and ferritin iron cores by means of evaluation of the Debye temperature using the temperature dependence of the spectral center shift obtained with two different fitting procedures and the second order Doppler shift approach. The Debye temperature, evaluated as ΘD=502±24K for Ferrum Lek and ΘD=461±16K for human liver ferritin, demonstrated a very small difference in the Fe atom vibrations, reflecting a slightly smaller rigidity in the iron cores in human liver ferritin.

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.

Comparative study of iron oxide nanoparticles as-prepared and dispersed in Copaiba oil using Mössbauer spectroscopy with low and high velocity resolution.

Iron oxide nanoparticles, probably magnetite, as-prepared and dispersed in Copaiba oil were studied by Mössbauer spectroscopy using two different spectrometers: with a low velocity resolution (512 channels) for measurements at 295 and 21K and with a high velocity resolution (4096 channels) for measurements at 295 and 90K. The fitting of all measured spectra demonstrated that usual models applied to fit Mössbauer spectra of magnetite and maghemite particles were not suitable. Therefore, the recorded spectra were fitted using a large number of spectral components on the basis of better quality of the fit and linearity of differential spectra. The number of components obtained for the better fit appeared to be different for spectra measured with a low and a high velocity resolution. However, these results demonstrated differences of Mössbauer parameters for iron oxide nanoparticles as-prepared and dispersed in Copaiba oil at applied temperatures. The effect of Copaiba oil molecules on Mössbauer parameters may be a result of the interactions of polar molecules such as kaurinic acid with nanoparticles' surface.

Comparative study of the iron cores in human liver ferritin, its pharmaceutical models and ferritin in chicken liver and spleen tissues using Mössbauer spectroscopy with a high velocity resolution.

Application of Mössbauer spectroscopy with a high velocity resolution (4096 channels) for comparative analysis of iron cores in a human liver ferritin and its pharmaceutically important models Imferon, Maltofer(®) and Ferrum Lek as well as in iron storage proteins in chicken liver and spleen tissues allowed to reveal small variations in the (57)Fe hyperfine parameters related to differences in the iron core structure. Moreover, it was shown that the best fit of Mössbauer spectra of these samples required different number of components. The latter may indicate that the real iron core structure is more complex than that following from a simple core-shell model. The effect of different living conditions and age on the iron core in chicken liver was also considered.

Mössbauer spectroscopy with a high velocity resolution: advances in biomedical, pharmaceutical, cosmochemical and nanotechnological research.

The methodological principles of velocity resolution as additional characteristic of the quality of both Mössbauer spectrometer velocity driving system and Mössbauer spectrum were briefly considered. Significantly better quality of Mössbauer spectra measured with a high velocity resolution in comparison with those measured with a low velocity resolution was demonstrated. The main advances of recent studies of iron containing biomolecules, pharmaceutical products, meteorite samples and nanoparticles using Mössbauer spectroscopy with a high velocity resolution were considered and advantages of this technique were shown.

Heme iron state in various oxyhemoglobins probed using Mössbauer spectroscopy with a high velocity resolution.

A comparative study of oxyhemoglobins from pig, rabbit, normal human and patients with blood system malignant diseases was performed using Mössbauer spectroscopy with a high velocity resolution at 90 K. Mössbauer spectra were fitted with the help of two models: using one quadrupole doublet (model of equivalent iron electronic structure in α- and ß-subunits of hemoglobins) and superposition of two quadrupole doublets (model of non-equivalent iron electronic structure in α- and ß-subunits of hemoglobins). The results obtained using both models demonstrated small variations of hyperfine parameters that were related to the heme iron state variation in different hemoglobins. These results were compared with structural and functional differences of the hemoglobins investigated.

Mössbauer spectroscopy with a high velocity resolution in the study of iron-containing proteins and model compounds.

Mössbauer spectroscopy with a high velocity resolution was used for comparative studies of human adult, rabbit and pig oxyhemoglobins, human liver ferritin and its pharmaceutically important models Imferon and Maltofer(®) as well as liver and spleen tissues from normal and lymphoid leukemia chicken. These studies revealed small variations of Mössbauer hyperfine parameters which were related to small variations of iron electronic structure and stereochemistry in these samples.

Determination of the iron state in ferrous iron containing vitamins and dietary supplements: application of Mössbauer spectroscopy.

Determination of the iron state in commercially manufactured iron containing vitamins and dietary supplements is important for evaluation of pharmaceuticals quality. Mössbauer (nuclear gamma-resonance) spectroscopy was used for analyzing the iron state in commercial pharmaceutical products containing ferrous fumarate (FeC(4)H(2)O(4)), ferrous sulfate (FeSO(4)), ferrous bisglycinate chelate (Ferrochel) and ferrous iron (hydrolyzed protein chelate). Mössbauer parameters and the iron states were determined for iron compounds in the studied pharmaceuticals. Various ferric and ferrous impurities were found in all of the commercial products. The quantities of ferric impurities exceeded the FDA limitation of 2% in products containing ferrous fumarate. The quantities of ferric impurities exceeded 58% and 30% in products containing ferrous bisglycinate chelate and ferrous iron (hydrolyzed protein chelate), respectively. The presence of ferrous and ferric impurities was not related to the ageing of the vitamins and dietary supplements. Two pharmaceutical products contained major iron compounds, the Mössbauer parameters of which did not correspond to the ferrous fumarate or ferrous bisglycinate chelate claimed by the manufacturer.

Hyperfine interactions in the iron cores from various pharmaceutically important iron-dextran complexes and human ferritin: a comparative study by Mössbauer spectroscopy.

Mössbauer spectroscopy has been used to study the hyperfine interactions in the iron cores of pharmaceutically important industrial and elaborated iron-dextran complexes (ferritin models) and human ferritin. Mössbauer spectra of frozen solutions and lyophilized samples of iron-dextran complexes at 87 K demonstrated magnetic, superparamagnetic and paramagnetic states of iron in various complexes. Mössbauer spectra of human ferritin in frozen solution and lyophilized form showed paramagnetic state of iron at 87 K. Small variations of Mössbauer hyperfine parameters were observed for different samples at 87 and 295 K, respectively, supposing the homogenous iron cores. The values of quadrupole splitting for iron-dextran complexes and ferritin in frozen solutions at 87 K varied from 0.639 to 0.744 mm/s while those of lyophilized samples at 87 K varied from 0.714 to 0.788 mm/s. The values of quadrupole splitting for iron-dextran complexes and ferritin in lyophilized form at 295 K varied from 0.687 to 0.741 mm/s. The values of hyperfine magnetic fields on the 57Fe nuclei in several iron-dextran complexes at 87 K varied from approximately 231 to approximately 485 kOe. These small variations of the hyperfine parameters were related to several types of the hydrous iron oxide microstructural modifications in the core and variations of the iron core size. The influence of lyophilization on the iron core structure was also assumed. In addition, Mössbauer spectra were evaluated in supposition of heterogeneous iron core in all samples.

Characterization of the heme iron in pyridoxylated hemoglobin cross-linked by glutaraldehyde using Mössbauer spectroscopy.

The heme iron in human adult hemoglobin modified by both pyridoxal-5'-phosphate and glutaraldehyde was characterized by Mössbauer spectroscopy and compared with non-modified hemoglobin. Mössbauer spectra of the samples were measured at 87 and 295 K (1yophilized form) and at 87 K (frozen solution). The values of quadrupole splitting for the oxy-form of modified hemoglobin were found to be lower than those of the oxy-form of hemoglobin without modifications in lyophilized form and frozen solution, respectively. On the other hand, the values of quadrupole splitting for the deoxy-form of modified and non-modified hemoglobins in frozen solution were the same. The Mössbauer spectra of the oxy-form of modified hemoglobin were also analyzed in terms of the heme iron non-equivalence in alpha- and beta-subunits of tetramer. The differences of the tendencies of temperature dependencies of quadrupole splitting for the oxy-form of modified and non-modified hemoglobins in lyophilized form were shown. These results indicated that the heme iron electronic structure and stereochemistry were changed in the oxy-form of pyridoxylated hemoglobin cross-linked by glutaraldehyde.

Mössbauer effect study of gamma-irradiated human oxyhemoglobin.

Preliminary results of the Mössbauer effect study of human adult oxyhemoglobin in erythrocytes exposed to gamma-irradiation with doses of approximately 100, approximately 300 and approximately 600 kGy are presented. Mössbauer spectra measured at 87 K have been analyzed in two ways. At first, to fit these spectra we used the four components oxyhemoglobin, deoxyhemoglobin, hemochromes and non-heme Fe(III) compound which had been obtained earlier from Mössbauer spectra of X-irradiated oxyhemoglobin by Chevalier et al. (1983). However, this approximation was not satisfactory. Then a new model of spectral fitting with five components was used. These were oxyhemoglobin, deoxyhemoglobin and components marked 1, 2 and 3. Using Mössbauer hyperfine parameters of each component the valence/spin states of iron ions were determined and possible complexes were considered. The most probable compounds for components 1, 2 and 3 were hematin and/or mu-oxodimers, methemoglobin hydroxide and/or hemichromes, and the high spin Fe(III) complex, respectively. Changes of the relative areas of Mössbauer subspectra of all components (its content in samples) versus doses were evaluated and the presence of the high and low spin aquomethemoglobin was indicated.

Mössbauer study of red blood cells from patients with erythremia.

Red blood cell samples from several patients with erythremia have been studied by Mössbauer spectroscopy. Quadrupole splitting and isomer shift for oxyhemoglobin from erythremic red blood cells and those of oxyhemoglobin from normal ones differ slightly, while these hyperfine parameters for deoxyhemoglobins are the same. An additional component in Mössbauer spectra of red blood cell samples was observed in some cases of erythremia. It is proposed that this component is related to ferritin-like iron and its content ranged from 13-15% to 5-7%.