| 1. |
- Serikov, V. V., et al.
(författare)
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Formation of solid solutions of gallium in Fe-Cr and Fe-Co alloys : Mossbauer studies and first-principles calculations
- 2014
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 614, s. 297-304
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Tidskriftsartikel (refereegranskat)abstract
- Investigation of Ga influence on the structure of Fe-Cr and Fe-Co alloys was performed with the use of Mossbauer spectroscopy and X-ray diffraction methods. The experimental results are compared with results of first-principles calculations of the mixing and solubility energies for Ga in an Fe-X (X = Co, Cr) alloy both in ferromagnetic and paramagnetic states. It is shown that Ga mainly goes into the solid solutions of the base alloys. In the alloys of the Fe-Cr system, doping with Ga handicaps the decomposition of solid solutions, observed in the binary alloys, and increases its stability. In the alloys with Co, Ga also favors the uniformity of solid solutions. The results of the first-principles calculations testify in favor of a preferable dissolution of Ga in the FeCo regions of a multicomponent structure rather than FeCr regions, both types of regions being in the ferromagnetic state at the temperature of annealing. The analysis of Mossbauer experiments gives some grounds to conclude that if, owing to liquation, clusterization, or initial stages of phase separation, there exist regions enriched in iron, some amount of Ga atoms prefer to enter the nearest surroundings of iron atoms, thus forming binary Fe-Ga regions (or phases).
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| 2. |
- Protasov, A. V., et al.
(författare)
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A mass spectrometric approach to study the interaction of amyloid beta peptides with human alpha-2-macroglobulin
- 2021
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Ingår i: Biochimie. - : Elsevier BV. - 0300-9084. ; 191, s. 62-68
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Tidskriftsartikel (refereegranskat)abstract
- We used MALDI-MS to study the interaction of amyloid beta (A beta) peptides with alpha-2-macroglobulin (alpha 2M). The binding of amyloid beta (A beta) peptides to alpha-2-macroglobulin (alpha 2M) was found to inhibit the ability of trypsin to cleave out the peptide alpha 2M 705-715 (Pep-alpha 2M) from alpha 2M. This was observed with both purified alpha 2M and alpha 2M in human serum. We found that A beta 1-38, A beta 1-40, and A beta 1-42, all inhibit the interaction of alpha 2M with trypsin, with inhibition rate independent of the length of the A beta peptide. Further, we show that for complete inhibition, two peptide molecules must be attached to one alpha 2M molecule; one for each of its two subunits. A region was revealed within the A beta sequence, in which proteolytic cleavage (Lys-28) and oxidation (Met-35) lead to a loss of their ability to inhibit the interaction of trypsin with alpha 2M. Furthermore, we show that after the formation of a trypsin complex with alpha 2M and cleavage of alpha 2M to produce the alpha 2M 705-715, A beta peptides continue to bind to the protein in the same proportions. However, A beta peptides treated with DMSO lost their ability to bind to alpha 2M and thereby to inhibit the interaction of trypsin with alpha 2M. While maintaining their primary structure, such an effect can be explained only by conformational changes in the peptides, suggesting the possibility to use our analytical approach to distinguish between conformational isomers of A beta peptides. (C) 2021 Published by Elsevier B.V.
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| 3. |
- Zhirnov, Ivan, et al.
(författare)
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New Approach of True Temperature Restoration in Optical Diagnostics Using IR-Camera
- 2017
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Ingår i: Journal of thermal spray technology (Print). - : Springer. - 1059-9630 .- 1544-1016. ; 26:4, s. 648-660
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Tidskriftsartikel (refereegranskat)abstract
- The laser treatment processes are specified due to the laser-matter interaction instabilities. Modern additive manufacturing technologies such as selective laser melting provide layer-by-layer part growth with continuous operation for hours and days but without adequate controlling systems at present. In this paper, a method for determining a temperature in the laser action zone during the process based on a study of microscopic structure, phase and element analyses of the processed material is proposed. A fixed point corresponding to melting temperature was acquired, and the corresponding emissivity coefficient was calculated with the assumption of its wavelength and temperature independence. The experimental data were corroborated with good agreement with mathematical calculations. The obtained results reveal an impact of scanning speed and of laser emission power on temperature in molten zone, which presents interest for optimization of laser-processing technologies and more specifically selective laser melting process parameters.
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