Vol 50, No 4 (2016)

This work is devoted to mathematical modeling of processes that take place in a biotechnical system for extrarenal purification of human blood using a wearable artificial kidney. Processes of peritoneal dialysis and dialysis fluid regeneration by sorption and electrolysis are also described.

In the work, we present results of the mathematical modeling of hemodynamic processes of a system of auxiliary blood circulation (ABC) of pulsatile type with an ejection volume of 30 cm³ and two types of domestic mechanical heart valves. We show the influence of the type of inlet valve and the angle of its orientation on hemodynamic processes that occur during the operation of the blood pump. On the basis of results obtained, we give recommendations for the selection of the type of valve and its spatial arrangement in order to ensure optimal blood flow and minimization of stagnant zones inside the chamber of the blood pump.

This article reviews the criteria for assessment of hemolysis used in simulating the flow through a ventricular assist axial flow blood pump. The object of study is a model of the flow path of an axial pump consisting of a flow straightener, impeller, and diffuser. In this study, blood is considered as an incompressible Newtonian fluid with constant viscosity and density. Its flow is considered as unsteady. In the process of simulation, non-interacting control particles are introduced into the computational domain. The trajectories of the particles represent the trajectories of red blood cell movement in blood. To calculate the equivalent shear stress applied to a particle in the stream, the stress tensor is calculated at each point of the trajectory. This paper presents an equation for conversion of the stress tensor components into the equivalent shear stress. The results of the conversion are used to construct experimental hemolysis curves. Based on the obtained data, the rate of hemolysis in the flow path is compared to that in other ventricular assist devices.

An organo-mineral composite bone-grafting material was developed and tested. The composite material is based on synthetic hydroxyapatite (HAP) (30-60 wt%) integrated into the matrix of poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel. The composite was shown to have a homogeneous and isotropic microstructure, mechanical strength of ~11 MPa, high degree of water absorption reaching 34%, and elastomeric properties under physio-logical conditions (strain at failure is 57%).

We describe here a method using an original means of marking the patient’s head to obtain a significant increase in the accuracy of frameless neuronavigation to the level of accuracy of classical stereotaxis. This method opens up wide perspectives for the use of frameless neuronavigation for stereotaxic interventions on the brain.

Two-dimensional models of multilayer piezoelectric peristaltic pumps were constructed. Geometric and physical parameters of the two-layer model were optimized. Conditions for excitation of a traveling deformation wave were investigated. The results of analytical modeling of piezoelectric pumps were compared to the results obtained by the finite element method. The results of this work can be used to increase the performance and power efficiency of infusion pumps.

This article considers an automated range shifter of variable thickness intended to adjust the proton beam energy in the 3D conformal proton radiotherapy of oncological diseases of the head and the neck. The range shifter was developed at the medico-technical complex of the Joint Institute for Nuclear Research (Dubna, Russia). The results of the experimental tests of the device show that it successfully fulfills its intended purpose. The developed range shifter is intended to be used as one of the main components of a new system for dynamic irradiation of deep-seated targets of complex shape.

The use of AFE interfaces in medical diagnostic equipment, including multipurpose devices, is discussed.

The development of personalized medicine throughout the world is linked with advances in basic sciences such as genetics and biochemistry. This relates primarily to the creation of technologies for targeted highefficacy treatment of cancers. The potential for fast and accessible individualized preparation of medical devices, medicines, and even organs has appeared with the application of 3D printers to medicine. Could the personalized approach to making osteointegrated implants for traumatology and orthopedics lead to the development of hightech products based primarily on additive technologies? And would customized implants be able to improve the care of patients requiring surgical treatment? Answers to these questions require close interaction between surgeons, healthcare administrators, materials engineers, and technologists. And even if we gain an understanding of the needs, implementation of projects of this type will involve legal and economic conditions whose complexity could well become a barrier to their introduction.