Vol 50, No 1 (2016)

Tissue spheroids formed from fibroblasts using a micromolded non-adhesive hydrogel were located using a three-dimensional (3D) bioprinter on the surface of a nanofibrous polyurethane matrix produced by electrospinning. It was shown that the tissue spheroids attach to the matrix surface within a few hours and completely flatten after several days, indicating high biocompatibility of the matrix used. Tissue structures formed by the attachment and spreading of tissue spheroids on an electrospun matrix are a new technological platform for biofabrication and 3D bioprinting of tissues and organs.

The research is aimed at studying the topology of energy-efficient areas on the epicardial surface. The data enable determination of optimal areas for implantation of microelectromechanical systems (MEMS), including for their application for electrotherapy of the heart. A non-invasive method of assessing epicardium kinematic activity of the left ventricle of the heart in patients with various cardiovascular diseases was used for predicting the localization of implanted devices.

The article presents a mathematical model of blood flow in the inlet apparatus of an axial pump to support the ventricle. The inlet apparatus includes a curved cannula and a fixed flow straightener with three or four blades. The main control parameters are the length of the inlet portion of the cannula, the length of the outlet portion of the cannula, the inner diameter, the bending angle of the cannula, and the radius of the knee. Flow velocity at the wall is considered to be zero. The flow of blood is considered to be stationary; transient processes are not considered. Blood is considered to be a single-phase incompressible viscous Newtonian fluid. The study aims at identifying the unevenness of the flow incident on the rotor blades and at identifying stagnation zones. According to the results of calculations with various geometrical parameters, a divider is installed in the inlet apparatus model to address identified effects. Variable parameters of the divider are the radius of curvature and the length of the straight section.

The article investigates the effect of training the eye muscles in patients with strabismus during the training and its follow-up and, using videooculography, evaluates changes in the effectiveness of eye muscle functioning. The research results indicate the possibility of adjusting the treatment of strabismus by training combined with the pro-posed control method.

The article studies the problem of compression of data recorded by ECG sensors of mobile heart activity monitoring systems. An ECG data compression algorithm is presented which is based on transformation of coefficients of a discrete wavelet transform implemented using a computing device with limited processing power and low power consumption. The algorithm was tested on real signals and demonstrated its effectiveness.

A model describing the occurrence of methodological error in Doppler ultrasound measurement of blood flow velocity using contrast agents is suggested. The methodological error is due to the radiation pressure force. The influence of the contrast agent, the ultrasound parameters, and the vessel type on the magnitude of the methodological error in the blood flow velocity measurement was studied.

Coatings of aluminum oxide, rutile, and anatase formed on titanium alloy VT6 implants were tested. The values of the porosity in the micro- and nanoranges, the elemental composition, and the biocompatibility of the coatings prepared by thermal spraying of aluminum oxide with further microarc modification were measured.

The surface of polyurethane membranes of breast prostheses that were present in the human body for a long time were studied with instrumental methods of IR and Raman spectroscopy, atomic force microscopy, and energy dispersive spectrometry. It was found that the membrane surface was partially covered by plaque containing calcium and phosphorus.

Daily inspections of the radiation output of accelerator radiation beams prior to patient treatment are a compulsory component of all international recommendations on quality assurance. In the classic version, such an inspection is performed using standard “wired” (connected by wires) dosimetric equipment, such as calibrated ionization chambers or detector matrices. However, in the case of testing of a large number of accelerators and lack of appropriate radiological equipment and personnel, morning inspections may affect the beginning time of the treatment process. To accelerate this procedure, the N.N. Blokhin Russian Cancer Research Center of the Russian Academy of Medical Sciences developed and implemented a wireless technique of morning inspections using portal imaging devices for testing constancy of the absolute dose of photon radiation and assessing the accuracy of the multileaf collimator. The performance of the system for data transmission between the department server and the accelerator console, as well as the possibility of imaging, is checked simultaneously with the morning inspection.