Vol 51, No 2 (2017)

Biomechanical properties of vascular prostheses measured under different experimental conditions were compared. Strength and viscoelastic tests were conducted both under normal conditions (in air, at room temperature) and under conditions close to the internal environment of human body (in saline, at 37°C). There was a statistically significant difference between the results of measurement of the elastic hysteresis and the Young’s modulus (measured in the linear elastic region) under the two types of conditions. The obtained results prove the necessity of testing the mechanical characteristics under quasi-in vivo conditions. The testing method suggested in this work can be used for this purpose.

We present a method for segmenting images of tumors on MRI images of the brain based on an algorithm developed for automated determination of segmentation and outlining thresholds. Testing was performed by generating two databases of real MRI images of the brain, with radiology reports. Criteria for assessment of the quality of the segmentation results were: the Dice score, the Jaccard index, sensitivity, and specificity. Analysis of results obtained using this algorithm to solve the brain tumor MRI image segmentation task showed levels of sensitivity and specificity of 89% to 99%, which is evidence that assessment of the position and boundaries of brain pathology is highly effective.

The methods of three-dimensional printing widely used in the Russian Federation are discussed: FDM, SLA, SLS, and DMLS. Our own experience with three-dimensional modeling and prototyping of implants for reconstructive neurosurgical procedures is analyzed. An optimal method for three-dimensional printing of implants by direct laser metal sintering is developed and supported by evidence.

The task of developing means of forming biocoatings improving the characteristics of metal implant bases remains important and current in contemporary implantology. Creation of bioactive layers with high levels of compatibility with bone tissue on implant surfaces is beneficial for better adaptation of the body to the implant. Introduction of such coatings, lacking adverse (toxic) actions, into the living body should strengthen osteointegration with bone tissue and stimulate regeneration processes. Bioactive calcium phosphate layers are of particular interest, as these contain calcium phosphate, which is “native” to bone tissue. Studies in this direction will lead to the development of a new method in medicine − bone tissue engineering. A means of forming a calcium phosphate coating on the medical titanium alloy BT6 (Ti containing 3.5-5.3% by weight V, 5.3-6.8% Al) by plasma electrolytic oxidation (PEO) was developed. The calcium phosphate coating was obtained in a bipolar PEO regime in a glycerophosphate-containing electrolyte. The osteogenerating properties of the coating were assessed in fractures of the diaphyseal part of the femur in Wistar lab rats. The calcium phosphate PEO coating was found to accelerate osteogenesis and promoted the formation of good periosteal callus at the fracture site.

A means for the noninvasive diagnosis of bronchial asthma (BA) and identifying the location of pathological changes in the bronchopulmonary system based on the characteristics of the propagation of microwave electro-magnetic radiation through the human thoracic cavity is discussed. The method proposed here provides for the diagnosis of respiratory system diseases, particularly bronchial asthma, in patients of all age groups, including young children; the method also provides for monitoring patient status and the dynamics of illnesses throughout treatment.

The article considers the possibility of correcting immunoendocrine disorders in patients with ischemic heart disease using low-intensity microwave radiation at a frequency of 1 GHz. The study showed that the Aquaton device for low-intensity microwave therapy could be used to stimulate production of bradykinin, NO, IL-24, antioxidants, and soluble tumor necrosis factor-alpha receptor II by whole blood cells. Exposure to microwave irradiation was accompanied by a decrease in the caspase-1 content in mononuclear leukocytes with a simultaneous increase in the nuclear transcription factor NFκB level, promoting thereby normalization of the subclinical inflammatory process and correction of endothelial dysfunction.

An approach to controlling hand prostheses using foot and toe movements is proposed. Construction of a model hand prosthesis with independent finger movements is described. A wireless remote control system for the prosthesis by tactile insoles fitted into the shoes is presented. Transfer parameters are selected by a synthesis based on the required final foot positions in the input and output sides of the system. Pneumatic bellows parameters, bracing spring stiffness, and pressure in the pneumatic circuit are selected on the basis of size restrictions and forces on the fingers. The study was supported by the Russian Foundation for Basic Research (Grant No. 16-08-00305A).