Известия высших учебных заведений. Физика
The results of an experimental study of a sensor designed to detect and measure the concentration of nanoparticles in an aqueous medium based on optical dielectric microresonators with "whispering gallery" modes are presented. The change in the frequency and Q of the eigenmodes of the microresonator was studied in its interaction with silver nanoparticles. It is shown that this type of sensor can be used to measure extremely small concentrations of nanoparticles.
We report the first experimental evidence for the mitogenic action of cerium(IV) oxide and cerium(III) fluoride nanoparticles (CONs and CFNs) on the regeneration of a whole organism – freshwater flatworms Schmidtea mediterranea (planarian). Both types of cerium-containing nanoparticles are shown to be a highly potent mitogen for planaria. Both CONs and CFNs, in micro- and nanomolar concentrations, markedly accelerate planarian blastema growth, due to the enhancement of cellular proliferation, causing an increase in the mitotic index and in the quantity of blastema cells in regenerating planaria. CONs provided maximum activity at concentrations which were two orders of magnitude lower than those for CeF3. The valence state of cerium in cerium-containing nanoparticles plays a significant role in the planarian regeneration mechanism: CeO2 nanoparticles containing predominantly Ce4+ species presumably scavenge wound induced reactive oxygen species and moderately activate gene expression processes, while the regenerative action of CeF3 nanoparticles containing only Ce3+ species is manifested in the pronounced expression of the genes involved in cell division, differentiation and migration. This is the first report on the effect of cerium-containing nanoparticles on tissue regeneration in vivo, further revealing the mechanisms of their biological action, which enhances the possibility of their use in cellular technologies.
This paper addresses hybrid ion exchange membranes fabricated by the synthesis of amorphous zirconium phosphate (dopant contents from 0.5 to 24 wt%) directly in the pore and channel system of heterogeneous cation-exchange membrane RALEX® CM (by in situ technique). The incorporation of zirconium phosphate nanoparticles into the membrane system of pores and channels leads to the displacement of the pore water. As a result, the cation transport numbers increase. The hybrid materials thus obtained are characterized by increased ionic resistance and enhanced monovalent ion selectivity. The former effect was eliminated by fabrication of a surface-modified membrane. The relative simplicity of modification, together with the benefits of the hybrid materials make them promising for some membrane processes. Using 31P MAS NMR and elemental analysis, considerable difference between the zirconium phosphate composition inside and outside the membrane was found.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.