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Dome acrobatics is the most difficult team skydiving discipline. The article is devoted to increasing the effectiveness of assessing the functional state of skydivers, optimizing professional selection for important competitions, and individual adaptation of the training program during training camps and after competitions. A comprehensive assessment of the psychological and functional state of the regulatory systems (central nervous and vegetative) of skydivers using standardized diagnostic computer programs of the Neurosoft-Polyspectr 8E complex (Russia) is supplemented by a method patented by the authors for assessing the professional suitability of specialists in dangerous professions to work in extreme conditions. The integrative index of professional fitness for extreme activities (STI) allows you to evaluate the effectiveness of training and predict sports results in extreme disciplines, including dome acrobatics. Based on the dynamics of STIs, an individual correction of the functional indicators of skydivers is carried out.

Purpose: Reducing the undesirable systemic effect of photodynamic therapy (PDT) can be achieved by incorporating a photosensitizer in microparticles (MPs). This study is devoted to the preparation of biocompatible biodegradable MPs with the inclusion of the natural photosensitizer Radachlorin (RС) and an assessment of the possibility of their use for PDT. Methods: RC-containing MPs (RС MPs) with poly(lactic-co-glycolic acid) copolymer (PLGA) matrix were prepared by a double emulsion solvent evaporation methods. The size and morphology of RC MPs were surveyed using scanning electron microscopy, confocal laser scanning microscopy, and dynamic light scattering. The content of RC, its release from RC MPs, and singlet oxygen generation were evaluated by the optical spectroscopy. Cellular uptake and cytotoxic photodynamic effect of RC MPs were investigated with in vitro assays. Results: The average diameter of the prepared RC MPs was about 2-3 μm. The RC MPs prepared by the water/oil/oil method had a significantly higher inclusion of RC (1.74 μg/mg) then RC MPs prepared by the water/oil/water method (0.089 μg/mg). Exposure of the prepared RC MPs to PDT light radiation was accompanied by the singlet oxygen generation and a cytotoxic effect for tumor cells. The release of the RC from the RC MPs was prolonged and lasted at least two weeks. Conclusion: PLGA RC MPs were found to cause a photoactivated cytotoxic effect for tumor cells and can be used for local application in PDT of tumors. ispartof: ADVANCED PHARMACEUTICAL BULLETIN vol:11 issue:3 pages:458-468 ispartof: location:Iran status: published

The effectiveness of carbon nanotubes (CNT) deagglomeration by rapid expansion of supercritical suspensions (RESS) in nitrogen and carbon dioxide fluids was studied in this work. Two different mechanisms of deagglomeration were proposed for these two fluids at various temperature and pressure conditions. Ultrasound attenuation spectroscopy was applied as an express method of determining median diameter and aspect ratio of CNTs. At least twofold reduction of the diameter was shown for CNT bundles processed by RESS technique. Aspect ratio of processed CNTs, calculated from acoustic attenuation spectra, increased to 340. These results were in a good agreement with atomic force microscopy data.

Ultrasound attenuation spectroscopy was applied to develop an express method for determining two dimensions of cylindrical nano-objects in colloids. For this we offered to perform measurements of attenuation spectra for two independent states of colloids: with the isotropic distribution of nano-objects and with orientation of nano-objects across the ultrasound beam. The oriented state of the nano-objects is achieved in the flowing colloid due to flow acceleration in the constricted channel. As a criterion of maximum orientation of nano-objects along the flow we used the decreasing of longitudinal viscosity close to the asymptotic value. A significant difference was found between attenuation spectra measured in two states for three aqueous colloids of carbon nanotubes and nanofibers with aspect ratio from 27 to 415. The diameter values from 5 to 21 nm of the nano-objects, calculated from attenuation spectra of oriented state, corresponded to TEM and AFM data. We suggested the methodology for evaluation of the aspect ratio of the cylindrical nano-objects in colloids based on the attenuation spectra in two states of colloids and the calibration function which should be preliminary defined using acoustic and microscopy tests of reference colloids.

A comparative study is made of the use of transmission electron microscopy, dynamic light scattering, and acoustic spectroscopy for measuring the sizes of nanoparticles in stable colloidal solutions of Al2O3, TiO2, SiO2, and ZnO at different concentrations and mean nanoparticle diameters. For solutions containing dendritic agglomerates of nanoparticles along with individual nanoparticles, it is found that acoustic spectroscopy can be used to measure the sizes of individual nanoparticles and dynamic light scattering can be used to measure sizes of objects from a mass of nanoparticles and their agglomerates.

Graphical abstract, A method for determining the critical values of the flow speed and the flow constriction degree characteristic of the alignment of cylindrical nano-objects in a flowing suspension is proposed. Previously, the alignment process of cylindrical nano-objects in suspensions was investigated by using birefringence of the polarized light and the small-angle X-ray scattering. While both methods are suitable for measuring the alignment degree of cylindrical nano-objects in suspensions diluted down to low concentrations, they are restricted for the application to undiluted concentrated suspensions because of non-transparency and multiple scattering of X-rays. In addition, the use of the second method requires an expensive synchrotron equipment. We present a simple and faster method based on the direct ultrasound attenuation measurements of longitudinal viscosity of a suspension containing cylindrical nano-objects, which decreases monotonically, approaching its asymptotic value with increase in the flow speed and the flow constriction degree. The principle and advantages of the proposed method are as follows: • The cylindrical nano-objects align along an accelerated flow at overcritical values of the flow speed and the constriction degree. • The critical values correspond to the state of a suspension possessing viscosity close to the asymptotic value. • The method is applicable to undiluted concentrated suspensions, including opaque ones.

The method of acoustic spectroscopy is used for the first time for investigating the spectra of ultrasonic attenuation in the range of 3–100 MHz on oriented carbon nanotubes in the stabilized aqueous dispersion. The anisotropy of attenuation of ultrasound manifests itself in a significant distinction between the attenuation spectra for preferential perpendicular and parallel orientation of carbon nanotubes with respect to the wave-propagation direction. A qualitative agreement of the measured-spectra shape with that of the attenuation spectra calculated from the theoretical model is obtained.

Ultrasound attenuates when propagating through aqueous dispersions of carbon nanotubes. We established a significant difference in the ultrasound attenuation frequency spectra for the nanotubes oriented either along or across the ultrasound beam. This effect can be used for calculating geometrical and rheological properties of nanofiber materials dispersed in liquids. Keywords: Ultrasound attenuation, Carbon nanotubes, Nanofibers