Radiation Characteristics of Europium-Containing Control Rods in a SM-2 Reactor after Long-Term Operation

Data are presented on the activity of europium isotopes accumulated in the absorbing elements of the control units of propulsion reactors (7.4·10¹⁸ Bq), BN-600 and BOR-60 fast-neutron reactors (2.6·10¹⁷ Bq), and the SM-2 research reactor (4.8·10¹⁵ Bq). A universal computational procedure was developed for investigating the radiation characteristics of absorbing elements. Features of this procedure are demonstrated for the example simulating the isotopic composition of SM-2 absorbing elements. It is shown that the computed and experimental values of the parameters of the height distribution of the activity of europium isotopes agree within the limits of computational and measurement errors, and the computed total activity over the volume of an absorption element is 15% higher than the experimental value.     

Hydrodynamics of a radial bearing with electrically conducting gas lubricant

The proposed method permits self-similar hydrodynamic calculation of a radial bearing with electrically conducting gas lubricant. The method takes account of the magnetic field.     

Nanotechnology for Topical Drug Delivery to the Anterior Segment of the Eye

Topical drug delivery is one of the most challenging aspects of eye therapy. Eye drops are the most prevalent drug form, especially for widely distributed anterior segment eye diseases (cataracts, glaucoma, dry eye syndrome, inflammatory diseases, etc.), because they are convenient and easy to apply by patients. However, conventional drug formulations are usually characterized by short retention time in the tear film, insufficient contact with epithelium, fast elimination, and difficulties in overcoming ocular tissue barriers. Not more than 5% of the total drug dose administered in eye drops reaches the interior ocular tissues. To overcome the ocular drug delivery barriers and improve drug bioavailability, various conventional and novel drug delivery systems have been developed. Among these, nanosize carriers are the most attractive. The review is focused on the different drug carriers, such as synthetic and natural polymers, as well as inorganic carriers, with special attention to nanoparticles and nanomicelles. Studies in vitro and in vivo have demonstrated that new formulations could help to improve the bioavailability of the drugs, provide sustained drug release, enhance and prolong their therapeutic action. Promising results were obtained with drug-loaded nanoparticles included in in situ gel.     

Nondestructive Evaluation of Changes in Local Density of Compressed Components from Composite Materials

The paper analyzes improvements in the gamma-method for nondestructive evaluation of density of constant-thickness components fabricated from highly filled composite materials. A facility designed for such measurements is described. The parameters of the radiation source and detecting instrument required to guarantee the high precision of the method are determined. Results of tests of the experimental facility are given.