卷 24, 编号 1 (2024)

Background and Objectives: Photoconvertible markers are a useful approach for conducting complex fundamental and applied research in medicine and biology. Usually, photoconvertible proteins or dyes are used for this, but have some disadvantages (low stability, requirement for genetic modification, etc.). The goal of this research was to develop safe and stable photoconvertible markers for cell application. Materials and Methods: The polymer markers were obtained from polyelectrolyte microcapsules under hydrothermal synthesis with fluorescent dye rhodamine B. The spectral properties were studied using confocal microscopy and spectrometry. Results: Photoconversion of microparticles under the influence of laser irradiation was carried out due to the ability of rhodamine B molecules to hypsochromic shift the emission band, catalyzed by carbon structures formed in the shells of microparticles during hydrothermal synthesis. Hydrothermal synthesis also significantly changed the size and shape of microparticles. The thermally treated polyelectrolyte microparticles had high stability and a bright fluorescent signal. The microparticles were actively internalized by the B16F10 mouse melanoma cell line, providing labeling for 70% of all cells in the population at a ratio of 10 microparticles per cell. At the same time, metabolic activity did not decrease below 85%, and the morphology and ability of B16F10 cells to synthesize melanin remained within normal limits. It has been shown that microparticles can be safely photoconverted inside B16F10 cells under laser irradiation. Conclusion: The proposed strategy is useful for complex studies on the behavior of individual melanoma cancer cells in genetically and phenotypically heterogeneous populations, and also for studying a metastatic process.

Background and Objectives: The aim of the research is to study the effect of ultrasound on the wettability of carbon fibers with a thermosetting binder and to determine the work of adhesion in the binder-fiber contact as part of the filament prepreg for additive technologies. Materials and Methods: Carbon fibers and carbon fiber roving with a width of 2 mm GG-200P were used in the research. Impregnation was carried out with ED-20 epoxy resin with a PEP hardener by pulling a harness at a speed of 10 mm/s through a gap of 2-3 mm between the end of the ultrasonic concentrator and the lower surface of the container with a binder. In total, 5 control and 5 experimental samples with a length of 300 mm were impregnated. Ultrasonic processing of samples was carried out on an experimental ultrasonic installation with an experimental ultrasonic generator controlled from a laptop and providing a discreteness of 10 Hz adjustment. The impregnation was carried out at a resonant frequency of 21650 Hz and an oscillation amplitude of the output end of the concentrator – 15 microns. The diameter of the output part of the concentrator was 14 mm, respectively, the length of the fiber bundle section was the same size at each time. After curing of the binder, the surface of the fibers was studied using a digital microscope Bresser LCD 50x–2000x at magnification x40 and x300. When impregnating control samples, the ultrasonic transducer of the installation was not included. Microphotographs were used to evaluate the wettability of the fibers with a binder under the influence of ultrasound and without ultrasound, and also to determine the edge angle of wetting and then – according to the Young – Dupree equation – the adhesion of the binder to the fiber surface. Results: The control bundle of carbon fibers is characterized by incomplete consolidation of fibers into a bundle, there are separate disoriented fibers, as well as separately existing conglomerates of fibers. Experimental bundles impregnated under the influence of ultrasound are monolithic structures with a continuous filling with a binder. At the same time, areas with inflows of the cured binder that violate the geometric shape of the prepreg are noted. Both control and experimental samples of harness are generally fully impregnated consolidated prepregs, there are no individual fibers or groups of fibers, which may be due to the initially regular structure of harness compared to randomly organized individual fibers into a thread. At the same time, in the control samples, the binder is unevenly distributed over the surface, individual inflows are noted, which indicates an insufficiently uniform impregnation of the harness. which is not observed on the prototypes. By calculating the adhesion performance for control and experimental samples using the experimentally obtained values of the wetting angle, it was found that its value is 44.71–48.98 mJ/m2 and 64.46–66.4 mJ/m2 , respectively, for control and experimental samples. Conclusion: A significant improvement in the wettability of the fibers with a binder has been found, manifested in a decrease in the wetting edge angle from 70–77° to 35–40°. Using the Young – Dupree equation, the adhesion of the binder to the fiber has been calculated and it has been shown that the effect of ultrasound during the impregnation of fibers increases the adhesion by an average of 39.7%

Background and Objectives: One of the main tasks for developing magnonic devices is to form and control spin wave beams. For this purpose, the decoration of ferrite films with magnetic or non-magnetic metal areas can be used. The aim of this work is to study the peculiarities of magnetostatic surface wave (MSSW) propagation in the channels formed in yttrium-iron garnet (YIG) films by deposition of 1.5 μm thick metal decorations from chromium (Cr) and permalloy (Py). Materials and Methods: Studied samples were fabricated on the base of 6.5 μm-thick epitaxial YIG film by the DC magnetron sputtering, photolithography, and ion etching techniques. Frequency dependencies of magnitude and phase of the transmitted MSSW signal at different applied magnetic field were measured with the help of a vector network analyzer and a microwave probe station. Calculation of the dispersions and insertion losses for MSSW propagating in the metallized YIG film was performed on the basis of Maxwell’s equations in the magnetostatic approximation, the Landau-Lifshitz equation, and standard electrodynamic boundary conditions. Results and Conclusion: The optimal channel width w relative to the antenna aperture providing channeling of the MSSW signal with the possibility of “antireflective effect” for the transmitted signal has been found to be w = 200 μm. It has been shown that for the formation of channeling effect, one needs to use a non-magnetic metal with the thickness leading to a transition to the “metallic” branch of the MSSW dispersion or a magnetic metal with the thickness resulting in bending of a short-wavelength part of MSSW dispersion. For the studied samples, it is d(Cr) = 1.5 μm and d(Py) = 30 nm, respectively. The obtained results demonstrate the possibility of using the channels in metallic decorations for the formation of directed spin wave beams.