Kazan Federal University

About: Kazan Federal University is a education organization based out in Kazan’, Russia. It is known for research contribution in the topics: Population & Chemistry. The organization has 9868 authors who have published 14390 publications receiving 135726 citations. The organization is also known as: Kazan (Volga region) Federal University & Kazan State University.

Classical transitions with the topological number changing in the early Universe

Abstract: We consider classical dynamics of two real scalar fields within a model with the potential having a saddle point. The solitons of such model are field configurations that have the form of closed loops in the field space. We study the formation and evolution of these solitons, in particular, the conditions at which they could be formed even when the model potential has only one minimum. These non-trivial field configurations represent domain walls in the three-dimensional physical space. The set of these configurations can be split into disjoint equivalence classes. We provide a simple expression for the winding number of an arbitrary closed loop in the field space and discuss the transitions that change the winding number. We also show that non-trivial field configurations could be responsible for the energy density excess that could evade the CMB constraints but could be important at scales which are responsible for the formation of galaxies and the massive primordial black holes.

Optimization of cytochrome c detection by acoustic and electrochemical methods based on aptamer sensors

Abstract: We report the effect of various factors such as oligonucleotide sequence, buffer composition, ionic strength for optimal determination of cytochrome c (cyt c) by DNA aptamer sensors using thickness shear mode acoustics (TSM) and electrochemical methods. Up to now, several DNA aptamers specific to cyt c have been selected and used in various sensing approaches including optical, electrochemical and mass sensitive transducers. We have analyzed the response of three different aptamers immobilized via biotin-neutravidin method on a gold support by TSM technique. Using this approach we have shown that only 76-length base sequence (apt 76) exhibited specific binding to cyt c with detection limit of 0.50 ± 0.05 nM. This aptamer was then studied under different ionic conditions showing an optimal response for HEPES buffer. Apt 76 based sensor has been also examined by electrochemical methods. However due to the electroactive nature of cyt c, the response of this aptamer was less favorable in comparison with TSM. The apt 76 based sensor was tested also in spiked samples of human plasma by TSM achieving a recovery of 92 ± 6.6% for 1 nM cyt c.

Structure and properties of aqueous dispersions of sodium dodecyl sulfate with carbon nanotubes

Abstract: The dispersing action of the surfactant (sodium dodecyl sulfate, SDS) on the carbon nanotubes (CNT) in aqueous medium has been studied. Electron microscopy, molecular docking, NMR and IR spectroscopies were applied to determine the physical-chemical properties of CNT dispersions in SDS—water solutions. It was established that micellar adsorption of the surfactant on the surface of carbon material and solubilization of SDS in aqueous medium contribute to improving CNT dispersing in water solutions. It was shown that the non-polar hydrocarbon radicals of a single surfactant molecule form the highest possible number of contacts with the graphene surface. Upon increase of the SDS in solution these radicals form micelles connected with the surface of the nanotubes. At the sufficiently high SDS concentration the nanotube surface becomes covered with an adsorbed layer of surfactant micelles. Water molecules and sodium cations are concentrated in spaces between micelles. The observed pattern of micellar adsorption is somewhat similar to a loose bilayer of surfactant molecules.

Combined inhibition of Aurora A and p21-activated kinase 1 as a new treatment strategy in breast cancer.

Abstract: The serine-threonine kinases Aurora A (AURKA) and p21-activated kinase 1 (PAK1) are frequently overexpressed in breast tumors, with overexpression promoting aggressive breast cancer phenotypes and poor clinical outcomes. Besides the well-defined roles of these proteins in control of cell division, proliferation, and invasion, both kinases support MAPK kinase pathway activation and can contribute to endocrine resistance by phosphorylating estrogen receptor alpha (ERα). PAK1 directly phosphorylates AURKA and its functional partners, suggesting potential value of inhibiting both kinases activity in tumors overexpressing PAK1 and/or AURKA. Here, for the first time, we evaluated the effect of combining the AURKA inhibitor alisertib and the PAK inhibitor FRAX1036 in preclinical models of breast cancer. Combination of alisertib and FRAX1036 was evaluated in a panel of 13 human breast tumor cell lines and BT474 xenograft model, with assessment of the cell cycle by FACS, and signaling changes by immunohistochemistry and Western blot. Additionally, we performed in silico analysis to identify markers of response to alisertib and FRAX1036. Pharmacological inhibition of AURKA and PAK1 synergistically decreased survival of multiple tumor cell lines, showing particular effectiveness in luminal and HER2-enriched models, and inhibited growth and ERα-driven signaling in a BT474 xenograft model. In silico analysis suggested cell lines with dependence on AURKA are most likely to be sensitive to PAK1 inhibition. Dual targeting of AURKA and PAK1 may be a promising therapeutic strategy for treatment of breast cancer, with a particular effectiveness in luminal and HER2-enriched tumor subtypes.