Determination of oxidation state of iron in normal and pathologically altered human aortic valves

Czapla–Masztafiak, Joanna; Lis, Grzegorz; Gajda, Mariusz; Jasek, Ewa; Czubek, Urszula; Bolechała, Filip; Borca, Camelia N.; Kwiatek, Wojciech M.

doi:10.1016/j.nimb.2015.04.026

Cited by 8 publications

(4 citation statements)

References 21 publications

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“…Looking at the edge energy histogram and the corresponding oxidation state map (Figure a,b), around 30 % of the voxels are dominated by iron impurities in the form of Fe 3+ , <1 % in the form of Fe 2+ , and 69 % of an Fe 2+/ Fe 3+ mixed‐valence state with different Fe 2+ and Fe 3+ proportions . Further, we can see that the outer ASA envelope occludes mostly Fe 3+ or iron species with an edge energy greater than 7123 eV.…”

Section: Figurementioning

confidence: 96%

Localization and Speciation of Iron Impurities within a Fluid Catalytic Cracking Catalyst

et al. 2017

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Fluid catalytic cracking is a chemical conversion process of industrial scale. This process, utilizing porous catalysts composed of clay and zeolite, converts heavy crude-oil fractions into transportation fuel and petrochemical feedstocks. Among other factors iron-rich reactor and feedstream impurities cause these catalyst particles to permanently deactivate. Herein, we report tomographic X-ray absorption spectroscopy measurements that reveal the presence of dissimilar iron impurities of specific localization within a single deactivated particle. Whereas the iron natural to clay in the composite seems to be unaffected by operation, exterior-facing and feedstream-introduced iron was found in two forms. Those being minute quantities of ferrous oxide, located near regions of increased porosity, and impurities rich in Fe , preferentially located in the outer dense part of the particle and suggested to contribute to the formation of an isolating amorphous silica alumina envelope.

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Section: Figurementioning

confidence: 96%

Localization and Speciation of Iron Impurities within a Fluid Catalytic Cracking Catalyst

et al. 2017

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“…The examples of applications are, among others, the structural characterization of chloroperoxidase compound I [9], the determination of ligand environment of zinc in different tissues of Zn-hyperaccumulating plants [10] and chemical structure of metalloproteins [11]. A lot of researches concern changes in oxidation states of trace elements in case of different pathologically altered cells and tissues, for example the studies of differences in iron and zinc oxidation state contained in healthy and neoplastic tissues of the human brain [12], iron in normal and stenotic human aortic valves [13] or copper inside single neurons from Parkinson's disease and control substantia nigra [14]. Another group of application is identification of elements' chemical species in biological systems, like sulfur in erythrocytes and blood plasma [15], selenium in human cancer cells [16], as well as arsenic in various cell structures [17].…”

Section: Introductionmentioning

confidence: 99%

X‐Ray Spectroscopy on Biological Systems

Czapla–Masztafiak¹,

Kwiatek²,

Sá³

et al. 2017

X-Ray Scattering

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In the field of biological studies, next to the standard methods, new tools are offered by contemporary physics. X-ray spectroscopic techniques enable probing electronic structure of occupied and unoccupied states of studied atom and distinguish the oxidation state, local geometry, and ligand type of elements that occur in biological material. Direct analysis using X-ray spectroscopy avoids many chemical preparation steps that might modify biological samples. The information obtained gives us insight into important biochemical processes all under physiological conditions. In this chapter we focus our attention to the application of X-ray spectroscopy to the study of biological samples, with special emphasis on mechanisms revealing interaction between DNA and different cytotoxic agents and in the determination of changes in oxidation state of different elements in pathologically altered human cells and tissue.

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Section: Introductionmentioning

confidence: 99%

“…The use of high-intensity focused beam obtained from synchrotron sources makes possible micro-analysis of elements that occur in biological material even at extremely low concentrations. 8,9 Direct speciation analysis using X-ray absorption spectroscopy (XAS) in tissue avoids many chemical preparation steps that might modify the chemical species present. 10 The aim of presented studies was to use the XAS imaging technique to determine the two-dimensional (2D) distribution of sulfur chemical species in different morphological parts of prostate tissue for the first time and find differences in chemical composition between them.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Distribution of Chemical Forms of Sulfur in Prostate Cancer Tissue Using X-ray Absorption Spectroscopy

et al. 2015

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The use of synchrotron radiation may shed more light on the study of prostate cancer, one of the leading diseases among men. In the presented study the microbeam setup at the PSI Swiss Light Source combined with fluorescence detected X-ray absorption spectroscopy (XAS) was applied to determine two-dimensional (2D) imaging of distributions of various chemical sulfur forms in prostate cancer tissue sections, since sulfur is considered important and essential in cancer progression. The research focused on prostate tissues obtained during routine prostatectomies on patients suffering from prostate cancer.Our previous studies using μ-XAS point measurements on prostate cancer cell lines showed the differences in fractions of various forms of sulfur between cancerous and non-cancerous cells. Therefore, in this experiment the chosen areas of prostate cancer tissues were scanned to get the full picture of the chemical composition of tissue, which is highly heterogeneous. The incident X-ray beams of energies tuned to spectroscopic features of the near-edge region of sulfur K-edge absorption spectra were used to provide contrast between chemical species presented in the tissue. Next, the relative content of the three main sulfur forms, found in biological systems, was calculated and the results are presented in a form of 2D color maps. These maps are correlated with the microscopic histological image of the scanned area.The main findings show that sulfur occurs in prostate tissue mainly in reduced form. The oxidized form of sulfur is present mostly in prostatic stroma, while sulfur in intermediate oxidation state is present in trace amount.

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Determination of oxidation state of iron in normal and pathologically altered human aortic valves

Cited by 8 publications

References 21 publications

Localization and Speciation of Iron Impurities within a Fluid Catalytic Cracking Catalyst

Localization and Speciation of Iron Impurities within a Fluid Catalytic Cracking Catalyst

X‐Ray Spectroscopy on Biological Systems

Investigating the Distribution of Chemical Forms of Sulfur in Prostate Cancer Tissue Using X-ray Absorption Spectroscopy

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