We report the successful inactivation of P. aeruginosa strain by femtosecond infrared (IR) laser radiation at the resonant wavelengths of 3.15 μm and 6.04 μm, chosen due to the presence of characteristic molecular vibrations in the main structural elements of the bacterial cells in these spectral ranges: vibrations of amide groups in proteins (1500–1700 cm−1), and C-H vibrations in membrane proteins and lipids (2800–3000 cm−1). The underlying bactericidal structural molecular changes were revealed by the stationary Fourier-transform IR spectroscopy, with the spectral peaks parameters being obtained by Lorentzian fitting with the hidden peaks revealed by the second derivative calculations, while no visible damage to the cell membranes was identified by scanning and transmission electron microscopy.

This article considers the nanoparticles suspended in the gas phase in the vicinity of a 3D-printed surface during additive manufacturing via Laser Beam Powder Bed Fusion (LB-PBF) and Directed Energy Deposition (DED). The results of this research show that the primary pollutants during the laser additive manufacturing using metal powder are aggregated core–shell nanoparticles with an average particle size of about 10 nm. High-resolution microscopy shows the chemical composition of the volume and surface of each particle; in particular, the “core” consists of Fe, Cr, and Ni atoms and the “shell” is a thin oxide layer.

Objectives: To study the oxide layer stability of certified dental implants of system "P", made based on TiO2 alloy with carbon coating. To perform a comparative statistical analysis of the obtained data with the available data for the dental implants of systems "A"Methods: X-ray microtomography and X-ray fluorescence analysis were used to study soft tissue biopsy specimens. Supernatants were studied by dynamic light scattering and transmission electron microscopy when simulating free emission of nanoscale metal oxide particles from the surface of dental implants as well as when simulating physical loading. A comparative analysis of three parameters of nanoscale particles was performed by statistical data analysis. The surface of the "P" system dental implant with surface treatment was analyzed by scanning electron microscopy.Results: Both free emission of nanoscale oxide layer particles and yield of nano- and microscale particles during simulation of physical load were confirmed. Statistically significant differences were noted in a comparative analysis of the size and frequency of occurrence of these particles in the supernatants obtained from the surfaces of three dental implant systems. The elemental composition of the particles and the composition and structure of the "P" system dental implants themselves were analyzed.

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.

Two approaches are proposed for the synthesis of bimetallic Au/Ag nanoparticles, using the pulsed laser ablation of a target consisting of gold and silver plates in a medium of supercritical carbon dioxide. The differences between the two approaches related to the field of “green chemistry” are in the use of different geometric configurations and different laser sources when carrying out the experiments. In the first configuration, the Ag and Au targets are placed side-by-side vertically on the side wall of a high-pressure reactor and the ablation of the target plates occurs alternately with a stationary “wide” horizontal beam with a laser pulse repetition rate of 50 Hz. In the second configuration, the targets are placed horizontally at the bottom of a reactor and the ablation of their parts is carried out by scanning from above with a vertical “narrow” laser beam with a pulse repetition rate of 60 kHz. The possibility of obtaining Ag/Au alloy nanoparticles is demonstrated using the first configuration, while the possibility of obtaining “core–shell” bimetallic Au/Ag nanoparticles with a gold core and a silver shell is demonstrated using the second configuration. A simple model is proposed to explain the obtained results.

Metal nanoparticlies are getting growing interest due to their magnetic properties. Such nanoparticlies can be used in preparation of new materials for electronic, also in medical and biological applications [1]. In our work the nanoparticles obtained by the laser photolysis of the mixtures containing vapors of various hydrocarbons (pentacarbonyl with benzole) and acetylene, iron. Another method of obtaining is a shock waves pyrolysis of the mixtures of Fe(CO)5 with C2H2 or C6H6 diluted with argon. Iron nanoparticles were formed in the shock tube behind incident shock waves at the temperatures of 700–2000 K [2]. We investigate the core/shell Fe and Fe oxides/carbon nanoparticles using different methods such as TEM, STEM, electron diffraction, EDS for element analysis and fast mapping on 200kV with FE on transmission electron microscope using special technique of precipitation nanoparticles to the TEM grid and protecting microscope of contamination. The TEM studying reveals two kinds of core/shell structures depends on a temperature in reactor. We found a composition including Fe and different Fe oxides near to monodispersing nanoparticles (d=2-25nm), edged by 1-8 carbon layers with overall dimensions ~2.3-30nm, that depends on technology of obtaining. The nanoparticles are connecting to each other, forming agglomerates and holding together with van der Waals bonds.