Nanotechnologies in Russia最新文献

The need to develop a surgical instrument that can most effectively and minimally invasively remove a malignant tumor, and distinguish and destroy only tumor cells without damaging the normal cells of healthy tissue surrounding the tumor is being considered. To achieve this goal, it is proposed to use nanodiscs with special magnetic, electronic and optical properties. Nanodiscs modified with recognition ligands (aptamers) are able to bind to tumor cells and destroy them under the influence of a weak, nonheating alternating magnetic field. This allows for effective tumor destruction while minimizing the impact on surrounding healthy tissue.

GaAs/AlAs(001) (2 × 4) is one of the most optimal substrates for optoelectronic and nanophotonic applications. Droplet epitaxy allows high-quality quantum dot (QD) arrays with the desired properties to be obtained, but the detailed mechanism of deposition and subsequent epitaxial growth is still questionable. In this paper, the growth mechanism of indium QDs on various GaAs/AlAs(001) surfaces is studied within calculations of density functional theory. Full geometry optimization, in which the coordinates of substrate atoms can be altered under adatom impact, is shown to be a straightforward technique for the simulation of adsorption processes. The obtained results are in good agreement with conventional methods and well-known findings. The proposed approach could become standard practice and extend the understanding of droplet epitaxy.

The mechanical behavior of porous chitosan particles with various diameters obtained by freeze drying is investigated. The morphology of the particles is visualized by scanning electron microscopy. It is shown that the particles have a predominantly spherical shape and a honeycomb-like structure with interpenetrating pores. The mechanical characteristics of the particle material are modeled using the neo-Hookean, second-order Yeoh, Blatz-Ko, and third-order Ogden foam hyperelastic models, based on the results of mechanical compression tests between parallel plates and numerical solution of the reverse-engineering problem using the finite-element method. Force-displacement curves are plotted for the proposed models and then verified in a similar full-scale experiment with particles of another diameter.

Using a small oscillating load (continuous stiffness measurement, CSM), in addition to the main quasi-static load, we determine the hardness, Young’s modulus, storage and loss moduli, mechanical loss coefficient ((tan delta )), and the plasticity characteristics in various components of the nanostructure and microstructure of pine (Pinus sylvestris) and spruce (Picea abies) wood. The contribution of structures of different scales to the ratio of the viscoelastic properties of early and late wood in the composition of one annual ring is determined. The plasticity characteristic δ_А is determined, and the influence of an additional oscillating load on the dynamic parameters of wood is assessed.

The aim of the work is to evaluate the effect of gold nanoparticles with a surface modified with fucose (Au-Fuc), lactose (Au-Lac), and galactose (Au-Gal) residues on the functional activity and expression of the transporter protein P-glycoprotein (Pgp). The work is performed using Caco-2 and HEK293 cells, which are incubated for 2 and 8 h with solutions of Au-Fuc, Au-Lac, and Au-Gal in a nutrient medium (450 and 300 µg/mL, 700 and 490 µg/mL, and 400 and 250 μg/mL, respectively). The amount of Pgp on the membranes of the Caco-2 cells is determined by the western blot method. The Pgp activity is assessed by the accumulation of fexofenadine Fex (150 µM) in cells by high-performance liquid chromatography (HPLC) with mass detection. Au-Fuc and Au-Gal do not change the amount of Pgp; Au-Lac increases the transporter level by 1.9 and 1.8 times upon 2 and 8 h of incubation respectively. Au-Fuc, Au-Lac, and Au-Gal increase the Pgp content in cells upon 8 h of incubation by 2.6, 3.5, and 5.3 times, which indicates a decrease in Pgp activity. When particles are incubated with HEK293 cells, no increase in the Fex levels are detected, which indicates the absence of a nonspecific increase in membrane permeability. Thus, the tested gold nanoparticles reduce the functional activity of Pgp in vitro.