186 results match your criteria: "Igor Sikorsky Kyiv Polytechnic Institute[Affiliation]"
Sensors (Basel)
May 2024
School of Information Science and Technology, Nantong University, Nantong 226019, China.
In this study, we investigated reconfigurable intelligent surface (RIS)-assisted device-to-device (D2D) communication systems over Nakagami- fading channels. To enhance the reliability of RIS-assisted D2D communications, we utilized the rate-splitting multiple access (RSMA) technique to maximize the achievable ergodic rate for our considered systems. Specifically, both devices decoded the common symbol by treating private symbols as interference, and then each private symbol was decoded by treating the other as interference.
View Article and Find Full Text PDFEnviron Res
August 2024
Taras Shevchenko National University of Kyiv, Kyiv, Ukraine. Electronic address:
The hydrogenation of CO to CH has gained considerable interest in terms of sustainable energy and environmental mitigation. In this regard, the present work aims to investigate the adsorptive concentration and CO methanation performance over CoFe and NiFe bimetallic catalysts supported on fumed alumina-silica SA96 support at 170-450 °C and under atmospheric pressure. The catalysts were prepared by wet impregnation method, subjected to calcination and further reduced with hydrogen, and their performance in CO methanation was investigated in a hydrogen-rich 2%CO-55%H-43%He gas mixture.
View Article and Find Full Text PDFJ Chem Phys
May 2024
Institute of Physics, 46 Nauky Ave., Kyiv 03028, Ukraine.
Interaction between a fixed point electric charge Q and a freely rotating point electric dipole with the magnitude P pinned near a plane interface between two dispersionless insulators with different dielectric permittivities ɛ1 and ɛ2 has been considered. It was shown that, as a result of this interaction and the interaction of the dipole with the polarization charges induced at the interface by the charge Q and the dipole itself, there arise regions where the dipole can possess either one or two equilibrium orientations. The spatial distributions of the electrostatic dipole energy Wtotal under the combined action of the charge Q and the induced interface polarization charges, as well as the equilibrium dipole orientations (orientation maps), the boundaries between the regions with different numbers of dipole orientations, and their evolution with the variation of problem parameters (the charge and dipole magnitudes, the mismatch between ɛ1 and ɛ2, and the charge-interface distance) were calculated.
View Article and Find Full Text PDFFront Netw Physiol
April 2024
Graduate School of Engineering Science, Osaka University, Osaka, Japan.
Dexterous postural control subtly complements movement variability with sensory correlations at many scales. The expressive poise of gymnasts exemplifies this lyrical punctuation of release with constraint, from coarse grain to fine scales. Dexterous postural control upon a 2D support surface might collapse the variation of center of pressure (CoP) to a relatively 1D orientation-a direction often oriented towards the focal point of a visual task.
View Article and Find Full Text PDFMagnetic nanocomposites (MNC) are promising theranostic platforms with tunable physicochemical properties allowing for remote drug delivery and multimodal imaging. Here, we developed doxorubicin-loaded FeO-Au MNC (DOX-MNC) using electron beam physical vapor deposition (EB-PVD) in combination with magneto-mechanochemical synthesis to assess their antitumor effect on Walker-256 carcinosarcoma under the influence of a constant magnetic (CMF) and electromagnetic field (EMF) by comparing tumor growth kinetics, magnetic resonance imaging (MRI) scans and electron spin resonance (ESR) spectra. Transmission (TEM) and scanning electron microscopy (SEM) confirmed the formation of spherical magnetite nanoparticles with a discontinuous gold coating that did not significantly affect the ferromagnetic properties of MNC, as measured by vibrating-sample magnetometry (VSM).
View Article and Find Full Text PDFNanoscale Adv
April 2024
V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine Pr. Nauky 41 Kyiv 03028 Ukraine
Carbon dots (CDs) are recognized as promising fluorescent nanomaterials with bright emission and large variations of photoluminescence quantum yield (PLQY). However, there is still no unique approach for explanation of mechanisms and recipes for synthetic procedures/chemical composition of CDs responsible for the enhancement of PLQY. Here, we compare photophysical behavior and PLQY of two types of CDs synthesized by different routes, leading to the different extent of oxidation and composition.
View Article and Find Full Text PDFJ Biotechnol
May 2024
Institute of Food Chemistry and Food Biotechnology, Justus Liebig University Giessen, Heinrich-Buff-Ring, 17, Giessen 35392, Germany; Faculty of Chemical Technology, Igor Sikorsky Kyiv Polytechnic Institute, Beresteiskyi Ave, 37, Kyiv 03056, Ukraine. Electronic address:
The biocatalytic aerobic "in-water" reduction of anthranilic acid to 2-aminobenzaldehyde by growing cultures of the basidiomycetous white-rot fungus Bjerkandera adusta has been studied. The high specific activity of Bjerkandera adusta towards the carboxylic group of anthranilic acid that allows avoiding the formation of the corresponding alcohol has been demonstrated using different substrate concentrations. The presence of ethanol as co-solvent allows increasing the yield of target product.
View Article and Find Full Text PDFChemistry
May 2024
Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
While π-bonds typically undergo cycloaddition with ozone, resulting in the release of much-noticed carbonyl O-oxide Criegee intermediates, lone-pairs of electrons tend to selectively accept a single oxygen atom from O, producing singlet dioxygen. We questioned whether the introduction of potent electron-donating groups, akin to N-heterocyclic olefins, could influence the reactivity of double bonds - shifting from cycloaddition to oxygen atom transfer or generating lesser-known, yet stabilized, donor-substituted Criegee intermediates. Consequently, we conducted a comparative computational study using density functional theory on a series of model olefins with increasing polarity due to (asymmetric) π-donor substitution.
View Article and Find Full Text PDFHeliyon
March 2024
Educational and Scientific Institute of Atomic and Thermal Energy, Department of Nuclear Power Engineering, National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 5 building, 6 Polytechnic Ave, 03056, Kyiv, Ukraine.
Using ANSYS FLUENT numerical modeling and mathematical modeling, the main characteristics of combustion processes during the combustion of natural gas were determined. In this work, the combustion processes and NO formation in the firebox were modeled at different loads of the GM- 50-14/250 boiler. The temperature distribution along the height of the firebox and the heat load on the screen panels were determined.
View Article and Find Full Text PDFSci Rep
February 2024
Division of Biomechanics and Research Development, Department of Biomechanics, and Center for Research in Human Movement Variability, University of Nebraska at Omaha, Omaha, NE, 68182, USA.
A rich and complex temporal structure of variability in postural sway characterizes healthy and adaptable postural control. However, neurodegenerative disorders such as Parkinson's disease, which often manifest as tremors, rigidity, and bradykinesia, disrupt this healthy variability. This study examined postural sway in young and older adults, including individuals with Parkinson's disease, under different upright standing conditions to investigate the potential connection between the temporal structure of variability in postural sway and Parkinsonism.
View Article and Find Full Text PDFCalcium signaling plays a crucial role in various physiological processes, including muscle contraction, cell division, and neurotransmitter release. Dysregulation of calcium levels and signaling has been linked to a range of pathological conditions such as neurodegenerative disorders, cardiovascular disease, and cancer. Here, we propose a theoretical model that predicts the modulation of calcium ion channel activity and calcium signaling in the endothelium through the application of either a time-varying or static gradient magnetic field (MF).
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
February 2024
Taras Shevchenko National University of Kyiv, Volodymyrska St. 64, Kyiv 01601, Ukraine.
The title compound dipotassium gadolinium(III) phosphate(V) molybdate(VI), KGd(PO)(MoO), was synthesized from a high-temperature melt starting from GdF as a source of gadolinium. Its structure is isotypic with other ( O)(PO) compounds, where = Na, K or Cs, and = rare-earth cation, = Mo or W. The three-dimensional framework is built up from [Gd(PO)(MoO)] anionic sheets, which are organized by adhesion of [GdPO] layers and [MoO] tetra-hedra stacked above and below these layers.
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
December 2023
Department of Chemistry, Taras Shevchenko National University of Kyiv, Volodymyrska Street 64, Kyiv, 01601, Ukraine.
The reaction of cadmium bromide tetra-hydrate with 3-amino-pyrazole (3-apz) in ethano-lic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, -poly[[di-bromido-cadmium(II)]-bis-(μ-3-amino-1-pyrazole)-κ : ;κ : ], [CdBr(CHN)] or [CdBr(3-apz)]. Its asymmetric unit consists of a half of a Cd cation, a bromide anion and a 3-apz mol-ecule. The Cd cations are coordinated by two bromide anions and two 3-apz ligands, generating -CdNBr octa-hedra, which are linked into chains by pairs of the bridging ligands.
View Article and Find Full Text PDFObjective: The aim: To create a three-dimensional simulation mechanical-mathematical model of the biomechanical system "Orthodontic appliance-maxilla", to study peculiarities of the stress-strained state of the maxilla.
Patients And Methods: Materials and methods: A simulation model of the biomechanical system "Orthodontic appliance-maxilla" was created using computed tomography (CBCT) data. Mathematical modeling was used to determine the stress-strain state of the simulation model.
Photochem Photobiol Sci
March 2024
Faculty Biomedical Engineering, Igor Sikorsky Kyiv Polytechnic Institute, 37, Beresteisky Avenue, Kiev, 03056, Ukraine.
The findings of the study demonstrate the impact of low-intensity laser and quasi-monochromatic light on the biosynthetic activity of the edible medicinal fungus L. edodes during submerged cultivation. An artificial lighting installation based on matrices of light-emitting diodes (LED) emitting light at 470 nm (blue), 530 nm (green), 650 nm (red), and argon gas laser (488 nm) was used.
View Article and Find Full Text PDFPharmaceuticals (Basel)
January 2024
National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 16/2 Yangel Str., 03056 Kyiv, Ukraine.
Despite efforts in osteosarcoma (OS) research, the role of inductive moderate hyperthermia (IMH) in delivering and enhancing the antitumor effect of liposomal doxorubicin formulations (LDOX) remains unresolved. This study investigated the effect of a combination treatment with LDOX and IMH on Saos-2 human OS cells. We compared cell viability using a trypan blue assay, apoptosis and reactive oxygen species (ROS) measured by flow cytometry and pro-apoptotic Bax protein expression examined by immunocytochemistry in response to IMH (42 MHz frequency, 15 W power for 30 min), LDOX (0.
View Article and Find Full Text PDFNanotechnology
February 2024
National Technical University of Ukraine 'Igor Sikorsky Kyiv Polytechnic Institute', Prospect Beresteiskyi 37, Kyiv 03056, Ukraine.
Formation of functional thin films for nanoelectronics and magnetic data storage via thermally induced diffusion-driven structural phase transformations in multilayer stacks is a promising technology-relevant approach. Ferromagnetic thin films based on Co Pt alloys are considered as a material science platform for the development of various applications such as spin valves, spin orbit torque devices, and high-density data storage media. Here, we study diffusion processes in Pt-Co-based stacks with the focus on the effect of layers inversion (Pt/Co/substrate versus Co/Pt/substrate) and insertion of an intermediate Au layer on the structural transitions and magnetic properties.
View Article and Find Full Text PDFThe paper studies oxidation resistance and electrical conductivity of dense coatings produced by vacuum-arc deposition technique on α-titanium thin (0.1 mm) substrate using a hot pressed TiAlC-TiC target. The coatings were deposited at low (7 mA/cm) and high (15 mA/cm) current densities on the substrate and marked LCD and HCD, respectively.
View Article and Find Full Text PDFChemistry
February 2024
Enamine Ltd., Chervonotkatska Street 78, Kyїv, 02094, Ukraine.
Electrophilic double bond functionalization - intramolecular enolate alkylation sequence was used to obtain a series of bridged and fused bicyclo[m.n.k]alkane derivatives (i.
View Article and Find Full Text PDFBiomimetics (Basel)
December 2023
Solid State Laser Laboratory, Department of Laser Technologies, Center for Physical Sciences and Technology, Savanoriu Ave. 231, 02300 Vilnius, Lithuania.
The liquid-repellent properties of AISI 304 stainless steel surfaces textured with a femtosecond laser were studied, both after spontaneous hydrophobization and when treated with stearic acid and octyltrimethoxysilane. Surface topography has been shown to play a critical role in determining these properties. Although textures containing only LIPSS exhibited poor liquid-repellency, the performance was significantly improved after engraving the microtexture.
View Article and Find Full Text PDFChemphyschem
February 2024
Faculty of Chemistry, Institute of Chemical Sciences, Maria Curie-Sklodowska University, Curie-Sklodowska Sq. 3, 20-031, Lublin, Poland.
A series of carbon composites were synthesised by carbonisation of resorcinol-formaldehyde resin mixtures with the addition of different amounts of sodium alginate (SA) and compared with a composite prepared using Na CO as a catalyst for the polymerisation reaction. The effect of operating parameters such as SA concentration and polycondensation time on the structural and morphological properties of resorcinol-formaldehyde resins (RFR) and carbon-derived composites was investigated for further use as adsorbents. The synthesised composites were characterised by FTIR, SEM, Raman spectroscopy and N adsorption/desorption techniques.
View Article and Find Full Text PDFJ Phys Condens Matter
December 2023
National Technical University of Ukraine 'Igor Sikorsky Kyiv Polytechnic Institute', Beresteiskyi Ave. 37, 03056 Kyiv, Ukraine.
We study the role of size effects on atomic collapse of charged impurity in the flat band system. The tight-binding simulations are made for the dice lattice with circular quantum dot shapes. It is shown that the mixing of in-gap edge states with bound states in impurity potential leads to increasing the critical charge value.
View Article and Find Full Text PDFScientific articles serve as vital sources of biomedical information, but with the yearly growth in publication volume, processing such vast amounts of information has become increasingly challenging. This difficulty is particularly pronounced when it requires the expertise of highly qualified professionals. Our research focused on the domain-specific articles classification to determine whether they contain information about drug-induced liver injury (DILI).
View Article and Find Full Text PDFMaterials (Basel)
November 2023
Igor Sikorsky Kyiv Polytechnic Institute, 37, Peremohy Ave., 03056 Kyiv, Ukraine.
Tribological tests in real conditions enable obtaining full data on the life of interacting machine parts. This article presents the results of operational tests on the elements of the support ring guidance system in a vertical ball-race mill. The guide and active armour operate under abrasive wear conditions with moderate-impact loads.
View Article and Find Full Text PDFACS Omega
November 2023
National Institute of Materials Physics, Magurele 077125, Romania.
Photocatalysis is one of the approaches for solving environmental issues derived from extremely harmful pollution caused by industrial dyes, medicine, and heavy metals. Titanium dioxide is among the most promising photocatalytic semiconductors; thus, in this work, TiO powders were prepared by a hydrothermal synthesis using titanium tetrachloride TiCl as a Ti source. The effect of the hydrochloric acid (HCl) concentration on TiO formation was analyzed, in which a thorough morpho-structural analysis was performed employing different analysis methods like XRD, Raman spectroscopy, SEM/TEM, and N physisorption.
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