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The main problem of radiation therapy is damage to normal tissues. One of the ways to solve this problem is radiomodification using cerium oxide nanoparticles (CONP's). The protective effect of CONP's can be measured with ferrous sulfate dosimeter (FSD). The dose modifying factors for tissue equivalent solution of FSD with CONP's in concentration 0.5 mg/ml irradiated by bremsstrahlung of 9 MeV electron beam were calculated. The addition of nanoparticles led to significant reduction in adsorbed dose. [ABSTRACT FROM AUTHOR]

The ability of CeO2 nanoparticles to modify the radiosensitivity of rat lymphosarcoma cells was studied. According to the results of the experiment, the CeO2 nanoparticles caused an increase in the viability of cells under irradiation. [ABSTRACT FROM AUTHOR]

Radiation treatment has been increasingly used for food processing. The possibility of using EPR spectrometry as adosimetry method is show in this work. The results of studying the EPR signals in wheat seeds presented in this article. The samples were irradiated by accelerated electrons, beam energy is 500 keV, dose range is 1 – 30 kGy. The EPR spectra were recorded 2 hours after irradiation and 23 days after irradiation. The study of free radical's time kinetics and fading estimation of integral intensity and peaks intensity was carried out. That is possible to register a signal for 23 days. [ABSTRACT FROM AUTHOR]

Radiation is one of the factors that constantly affects living organisms. The effect of natural radiation background is supplemented by radiation from artificial radioactive sources, the most common of them are medical devices used as diagnostic and therapeutic equipment. The use of radiation therapy is based on different radiosensitivity of normal and pathologically altered organs, tissues and cells of humans and animals. The search and application of substances that change the sensitivity of living organisms to ionizing radiation to reduce the damaging effect on healthy tissues, while maintaining a positive therapeutic effect, is an urgent issue of modern medical radiobiology. Currently, nanoparticles are widely used as such substances. This paper investigates the effect of mesoporous CeO2 nanopowder on the radiosensitivity of rat alveolar and peritoneal macrophages, dermal fibroblasts, and human cervical carcinoma cells. CeO2 nanoparticles were found to have selective radiomodifying properties in relation to various types of cells. CeO2 nanoparticles had a radioprotective effect on human fibroblasts, increasing their viability after irradiation and speeding up the differentiation of fibroblasts. The nanoparticles acted as radiosensitizers on tumor cells and macrophages, enhancing the damaging effect of ionizing radiation, but the mechanism for increasing sensitivity may be different in each case. The unique enzyme-like properties of cerium dioxide nanoparticles require further investigation of the mechanisms of their action on living systems. This can give an impetus to the development of new effective methods of radiotherapy for various diseases. [ABSTRACT FROM AUTHOR]

Nanophosphors in the amorphous state was first obtained by electron beam evaporation of bulk phosphors with an oxyapatite structure of the composition Sr2La8(1-x-y)ErxYbyGe6O26(x = y = 0.01÷0.15). A modification of the Raman spectrum was detected with a decrease in particles from the micro- to nanoscale state. The luminescent characteristics of the samples in micro- and nanostates were studied. The dependences of the luminescence intensity of nanophosphors for some transitions on the pump radiation power are analyzed. A laser pump critical power of ∼75 mW was found for the lines caused by the 4S3/2→4I15/2, 4S3/2→4I15/2 and 4I9/2→4I15/2 transitions. The effect of the cross-relaxation of the 4I11/2+4I11/2→4I15/2+4F7/2 state on the 4I11/2 level of the Er3+ ion has been established. This process is dominant, equally affects the filling of the 2H11/2, 4S3/2, and therefore level 4F9/2. [ABSTRACT FROM AUTHOR]

The principal possibility of synthesis of composite particles by the radiation-chemical method was shown. The composite particles were produced on the nanoscale range (50–80 nm) from aluminum oxide partially coated with silver. The coating percentage varied from 2–3 % to 16–40 %. The results of stabilization using polyethylene glycol and sodium citrate showed low sedimentation stability of the suspension. In addition, the biological activity of the nanopowder was investigated that showed a high level of antibacterial activity. [ABSTRACT FROM AUTHOR]

In this paper, studies of the influence of luminescence additives on the optical and luminescence properties of polyurethane based organic polymers are presented. Absorption and transmittance spectra reveal a decrease of transmittance with increasing filler concentration. In the X-ray excited luminescence spectra of nanocomposite samples with an inorganic filler, no bands, related to self-trapped exciton (STE) or core-valence luminescence (CVL) luminescence of barium fluoride are observed. This is due to the overlap of the organic phosphor absorption band and barium fluoride emission band. Measurements of decay time constant also reveal no long component of STE luminescence. This may be due to non-radiative energy exchange between barium fluoride and PPO. [ABSTRACT FROM AUTHOR]

Cerium dioxide nanoparticles are a promising material in many industries, for example, catalysis, chemical industry, biomedicine. Cerium ions located on the surface of nanoparticles easily enter into redox reactions. To increase the activity of such nanoparticles, it is necessary to increase the nonstoichiometry of nanoparticles by increasing the ratio of Ce3+/Ce4+ ions. The increase in non-stoichiometric nanoparticles of cerium dioxide is an important issue for increasing their catalytic activity. Annealing in a reducing atmosphere has been proposed as a method for increasing the concentration of Ce3+/Ce4+. [ABSTRACT FROM AUTHOR]

In this paper, studies of the effect of morphology and particle size of BaF2 nanopowders obtained by laser ablation method and by pulsed electron beam evaporation method on luminescent properties are presented. SEM-images of the morphology of all samples are presented. In the X-ray excited luminescence spectra of nanopowders, a redistribution of the relative intensity is observed between the self-trapped exciton and core-valence bands. This may be due to a smaller influence of particle size on the mechanism of formation of the cross-luminescence band. The change in the shape of the self-trapped exciton spectrum is also observed for nanosized samples. This effect can be associated with the possibility of the formation of certain STE configurations inside a nanoscale crystal due to the different relative position of the F and H centers parts with respect to each other. [ABSTRACT FROM AUTHOR]