During simulation of a water regime of heavy soils, it is necessary to know the isotropy parameters of any volume changes. Volume changes appear in both vertical and horizontal directions. In vertical directions, they appear as a topsoil... more
During simulation of a water regime of heavy soils, it is necessary to know the isotropy parameters of any volume changes. Volume changes appear in both vertical and horizontal directions. In vertical directions, they appear as a topsoil movement, and in horizontal directions as the formation of a crack network. The ratio between horizontal and vertical change is described using the geometric factor, rs. In the present paper, the distribution of volume changes to horizontal and vertical components is characterized by the geometric factor, in selected soil profiles, in the East Slovakian Lowland. In this work the effect of soil texture on the value of the geometric factor and thus, on the distribution of volume changes to vertical and horizontal components was studied. Within the hypothesis, the greatest influence of the clay soil component was shown by the geometric factor value. New information is obtained on the basis of field and laboratory measurements. Results will be used as i...
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Iron-based materials, especially magnetite nanocrystals, have found extensive applications in many fields. Novel challenges focus on a deeper understanding of interactions between magnetite and biological macromolecules for developing... more
Iron-based materials, especially magnetite nanocrystals, have found extensive applications in many fields. Novel challenges focus on a deeper understanding of interactions between magnetite and biological macromolecules for developing further applications in diagnostic and treatment methods in medicine. Inspired by ferritin, the iron storage protein occurring in bacteria, plant, animal, and human cells, we developed an artificial ferritin-like material known as magnetoferritin. We present structural studies of magnetoferritin samples prepared using a controlled in vitro physicochemical synthesis. Considerable structural and size changes were observed by increasing the iron content and post-synthesis treatment. We propose the modulation of colloidal stability by using suitable solvents. Ultraviolet and visible spectroscopy, dynamic light scattering, colloidal stability measurements, infrared spectroscopy, and small-angle X-ray scattering methods were employed. The presented results a...
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Abstract This work is devoted to the structural study of complex solutions of magnetic nanoparticles with lysozyme amyloid fibrils due to possible ordering of such system by applying the external magnetic field. The interaction of... more
Abstract This work is devoted to the structural study of complex solutions of magnetic nanoparticles with lysozyme amyloid fibrils due to possible ordering of such system by applying the external magnetic field. The interaction of magnetic nanoparticles with amyloid fibrils has been followed by atomic force microscopy and small-angle X-ray scattering. It has been observed that magnetic nanoparticles (MNPs) adsorb to lysozyme amyloid fibrils. It was found that MNPs alter amyloids structures, namely the diameter of lysozyme amyloid fibrils is increased whereas the length of fibrils is decreased. In the same time MNPs do not change the helical pitch significantly.
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Neurodegenerative disorders, including Alzheimer’s disease (AD), Parkinson’s disease (PD), or systemic amyloidosis, are characterized by the specific protein transformation from the native state to stable insoluble deposits, e.g., amyloid... more
Neurodegenerative disorders, including Alzheimer’s disease (AD), Parkinson’s disease (PD), or systemic amyloidosis, are characterized by the specific protein transformation from the native state to stable insoluble deposits, e.g., amyloid plaques. The design of potential therapeutic agents and drugs focuses on the destabilization of the bonds in their beta-rich structures. Surprisingly, ferritin derivatives have recently been proposed to destabilize fibril structures. Using atomic force microscopy (AFM) and fluorescence spectrophotometry, we confirmed the destructive effect of reconstructed ferritin (RF) and magnetoferritin (MF) on lysosome amyloid fibrils (LAF). The presence of iron was shown to be the main factor responsible for the destruction of LAF. Moreover, we found that the interaction of RF and MF with LAF caused a significant increase in the release of potentially harmful ferrous ions. Zeta potential and UV spectroscopic measurements of LAF and ferritin derivative mixtures...
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Obsah 1. Úvod 2. Magnetoferitín 3. Fyzikálno-chemické vlastnosti magnetoferitínu 4. Potenciálne bioaplikácie magnetoferitínu 5. Záver 1. Úvod Železo je esenciálnym prvkom živých systémov, pre-tože jeho nedostatok spôsobuje bunkovú smrť.... more
Obsah 1. Úvod 2. Magnetoferitín 3. Fyzikálno-chemické vlastnosti magnetoferitínu 4. Potenciálne bioaplikácie magnetoferitínu 5. Záver 1. Úvod Železo je esenciálnym prvkom živých systémov, pre-tože jeho nedostatok spôsobuje bunkovú smrť. Prebytok železa, najmä v podobe Fe 2+ iónov, je pre organizmus to-xický, preto je uskladnený v jadre zásobného proteínu, feritínu, kde sa železo ukladá vo forme hydratovaného železitého komplexného fosfátu [FeO(OH)] 8 [FeO(H 2 PO 4)] s kryštalografickou štruktúrou podobnou minerálu ferihydrit 1-3. Narušenie rovnováhy metabolizmu a uskladňovania železa vo feritíne úzko súvisí s rôznymi ochoreniami, aký-mi sú rakovinové alebo neurodegeneratívne ochorenia 4-7. Patologické zmeny sú sprevádzané prítomnosťou magneti-tu vo feritíne 8-14. Vzniknutá polykryštalická štruktúra feri-tínu môže hrať významnú úlohu v biochemických proce-soch, spojených s rôznymi chorobami. Doteraz nie je dos-tatočne preskúmané, či je vytvorenie biogénneho magneti-tu v mozgovom feri...
Nitrates, used especially in agricultural activities, are still a widespread risk for human health when exceeding recommended limits in various water drinking sources. Leaching of nitrates from soil to groundwater depends on various... more
Nitrates, used especially in agricultural activities, are still a widespread risk for human health when exceeding recommended limits in various water drinking sources. Leaching of nitrates from soil to groundwater depends on various factors (as soil properties, the size of soil particles, the ability of specific soil components and plant to absorb water and nitrates, meteorological conditions). The main goal of the presented work was to show nitrates leaching through different soil types. Different solute transport processes and solute distribution in the soil profile were demonstrated using HYDRUS-1D model simulation. This mathematical computation research could contribute to the set-up of suitable fertilizers concentration applied in agriculture on the soil surface with defined hydraulic properties. This method represents the economically advantageous and simple first step before fertilizers application. Particularly, the main idea of such theoretical simulations is a timely envir...
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Nitrates belong to the major nutrient required for plant growth and they are generally very well soluble in water often used as fertilizers in agriculture. The higher values of nitrates concentration will occur in the case of large... more
Nitrates belong to the major nutrient required for plant growth and they are generally very well soluble in water often used as fertilizers in agriculture. The higher values of nitrates concentration will occur in the case of large amounts use of fertilizer in intensive agriculture, pipe damage or damaged drainage near wells. The fertilization reduction could be one of this problem solution for health protection, environmental and economic reasons. In our study, the spectrophotometric determination of nitrates concentration in 5 times over-fertilized soil in lysimeters localized in the Eastern Slovakia Lowland showed nitrates leaching in the 40 cm layer of sandy soil, while in the silty-loam soil profile nitrates were not detected. The main goal of the experimental work was to show different nitrates leaching through two types of soil profile differing in hydraulic soil properties. Low retention capacity and high hydraulic conductivity of sandy soil (locality Poľany) were favourable...
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Ferritin, a spherically shaped protein complex, is responsible for iron storage in bacteria, plants, animals, and humans. Various ferritin iron core compositions in organisms are associated with specific living requirements, health state,... more
Ferritin, a spherically shaped protein complex, is responsible for iron storage in bacteria, plants, animals, and humans. Various ferritin iron core compositions in organisms are associated with specific living requirements, health state, and different biochemical roles of ferritin isomers. Magnetoferritin, a synthetic ferritin derivative, serves as an artificial model system of unusual iron phase structures found in humans. We present the results of a complex structural study of magnetoferritins prepared by controlled in vitro synthesis. Using various complementary methods, it was observed that manipulation of the synthesis technology can improve the physicochemical parameters of the system, which is useful in applications. Thus, a higher synthesis temperature leads to an increase in magnetization due to the formation of the magnetite phase. An increase in the iron loading factor has a more pronounced impact on the protein shell structure in comparison with the pH of the aqueous me...
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Magnetite mineralization in human tissue is associated with various pathological processes, especially neurodegenerative disorders. Ferritin’s mineral core is believed to be a precursor of magnetite mineralization. Magnetoferritin (MF)... more
Magnetite mineralization in human tissue is associated with various pathological processes, especially neurodegenerative disorders. Ferritin’s mineral core is believed to be a precursor of magnetite mineralization. Magnetoferritin (MF) was prepared with different iron loading factors (LFs) as a model system for pathological ferritin to analyze its MRI relaxivity properties compared to those of native ferritin (NF). The results revealed that MF differs statistically significantly from NF, with the same LF, for all studied relaxation parameters at 7 T: r1, r2, r2*, r2/r1, r2*/r1. Distinguishability of MF from NF may be useful in non-invasive MRI diagnosis of pathological processes associated with iron accumulation and magnetite mineralization (e.g., neurodegenerative disorders, cancer, and diseases of the heart, lung and liver). In addition, it was found that MF samples possess very strong correlation and MF’s relaxivity is linearly dependent on the LF, and the transverse and longitud...
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Various pathological processes in humans are associated with biogenic iron accumulation and the mineralization of iron oxide nanoparticles, especially magnetite. Ferritin has been proposed as a precursor to pathological magnetite... more
Various pathological processes in humans are associated with biogenic iron accumulation and the mineralization of iron oxide nanoparticles, especially magnetite. Ferritin has been proposed as a precursor to pathological magnetite mineralization. This study quantifies spectroscopically the release of ferrous ions from native ferritin and magnetoferritin as a model system for pathological ferritin in the presence of potent natural reducing agents (vitamins C and B2) over time. Ferrous cations are required for the transformation of ferrihydrite (physiological) into a magnetite (pathological) mineral core and are considered toxic at elevated levels. The study shows a significant difference in the reduction and iron release from native ferritin compared to magnetoferritin for both vitamins. The amount of reduced iron formed from a magnetoferritin mineral core is two to five times higher than from native ferritin. Surprisingly, increasing the concentration of the reducing agent affects on...
Research Interests: Genetics, Chemistry, Medicine, Ferrihydrite, Ferritin, and 3 moreMolecular sciences, Magnetite, and Ferrous
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Ferritins are proteins, which serve as a storage and transportation capsule for iron inside living organisms. Continuously charging the proteins with iron and releasing it from the ferritin is necessary to assure proper management of... more
Ferritins are proteins, which serve as a storage and transportation capsule for iron inside living organisms. Continuously charging the proteins with iron and releasing it from the ferritin is necessary to assure proper management of these important ions within the organism. On the other hand, synthetic ferritins have great potential for biomedical and technological applications. In this work, the behavior of ferritin during the processes of iron loading and release was examined using multiplicity of the experimental technique. The quality of the protein's shell was monitored using circular dichroism, whereas the average size and its distribution were estimated from dynamic light scattering and transmission electron microscopy images, respectively. Because of the magnetic behavior of the iron mineral, a number of magnetooptical methods were used to gain information on the iron core of the ferritin. Faraday rotation and magnetic linear birefringence studies provide evidence that ...
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The interaction of amyloid β-peptide (Aβ) with the iron-storage protein ferritin was studied in vitro. We have shown that Aβ during fibril formation process is able to reduce Fe(III) from the ferritin core (ferrihydrite) to Fe(II). The... more
The interaction of amyloid β-peptide (Aβ) with the iron-storage protein ferritin was studied in vitro. We have shown that Aβ during fibril formation process is able to reduce Fe(III) from the ferritin core (ferrihydrite) to Fe(II). The Aβ-mediated Fe(III) reduction yielded a two-times-higher concentration of free Fe(II) than the spontaneous formation of Fe(II) by the ferritin itself. We suggest that Aβ can also act as a ferritin-specific metallochaperone-like molecule capturing Fe(III) from the ferritin ferrihydrite core. Our observation may partially explain the formation of Fe(II)-containing minerals in human brains suffering by neurodegenerative diseases.
Research Interests: Biophysics, Chemistry, Biological Physics, Medicine, Ferrihydrite, and 3 morePeptide, Ferritin, and Rubredoxin
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Synthetic biological macromolecule of magnetoferritin containing an iron oxide core inside a protein shell (apoferritin) is prepared with different content of iron. Its structure in aqueous solution is analysed by small-angle synchrotron... more
Synthetic biological macromolecule of magnetoferritin containing an iron oxide core inside a protein shell (apoferritin) is prepared with different content of iron. Its structure in aqueous solution is analysed by small-angle synchrotron X-ray (SAXS) and neutron (SANS) scattering. The loading factor (LF) defined as the average number of iron atoms per protein is varied up to LF=800. With an increase of the LF, the scattering curves exhibit a relative increase in the total scattered intensity, a partial smearing and a shift of the match point in the SANS contrast variation data. The analysis shows an increase in the polydispersity of the proteins and a corresponding effective increase in the relative content of magnetic material against the protein moiety of the shell with the LF growth. At LFs above ∼150, the apoferritin shell undergoes structural changes, which is strongly indicative of the fact that the shell stability is affected by iron oxide presence.
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Synthetic biological macromolecule of magnetoferritin containing an iron oxide core inside a protein shell (apoferritin) is prepared with different content of iron. Its structure in aqueous solution is analysed by small-angle synchrotron... more
Synthetic biological macromolecule of magnetoferritin containing an iron oxide core inside a protein shell (apoferritin) is prepared with different content of iron. Its structure in aqueous solution is analysed by small-angle synchrotron X-ray (SAXS) and neutron (SANS) scattering. The loading factor (LF) defined as the average number of iron atoms per protein is varied up to LF=800. With an increase of the LF, the scattering curves exhibit a relative increase in the total scattered intensity, a partial smearing and a shift of the match point in the SANS contrast variation data. The analysis shows an increase in the polydispersity of the proteins and a corresponding effective increase in the relative content of magnetic material against the protein moiety of the shell with the LF growth. At LFs above ∼150, the apoferritin shell undergoes structural changes, which is strongly indicative of the fact that the shell stability is affected by iron oxide presence.