THE APPLICATION OF CONSTRUCTIONS MADE FROM BIODEGRADABLE MATERIAL WITH BIOACTIVE ACTION IN RECONSTRUCTIVE SURGERY OF MAXILLOFACIAL AREA

Currently, titanium plates and screws are widely used to fix bone fragments in maxillofacial surgery. The need for a second operation to remove the metal structure increases the patient's incapacity for work, the economic costs of treatment and the psychoemotional load on the patient associated with anxiety and additional stress. All this has led to the emergence of an alternative method of osteosynthesis using biodegradable plates and screws, which do not have these disadvantages. With all the positive properties of titanium fixators in recent years there has been a large number of publications on the increase in complications after metal osteosynthesis (MOS) using titanium bone plates and screws, which is from 5 to 18 %, therefore, there is a need to remove them after consolidation of bone fragments. The results of the study were the basis for finding ways to obtain the material without metal defect, from which it would be possible to make fixator in the form of plates and screws for the osteosynthesis in maxillofacial region. It was developed biodegradable material of bioactive action (EPU-GAP-LEV) based on polyurethane composition which contains 20 % hydroxyapatite, and 6 % levamisole for osteosynthesis fixator. It was proved effectiveness of EPU-GAP-LEV fixators for osteosynthesis in the treatment of the patients with fractures and deformations of facial skull. Positive results of own clinical researches in early and long terms testified to efficiency and perspective of use of polymeric (including EPU-GAP-LEV) miniplasts in surgical treatment of fractures of facial skull with shift.

ASSESSMENT OF BILIOSTATIC PROPERTIES OF MODERN TOPIC HEMOSTATIC MEANS USED IN HEPATIC SURGERY

Aim. To assess the biliostatic properties of modern topic hemostatic means and the developed glue composition for medical purpose, used in hepatic surgery in experiment. Materials and methods. The studies, aimed at assessment of the properties of local hemostatic means, were carried out on Wistar rats weighing 178 ± 10 g. The device for determination of leak proofness of hepatic stump with hydropression technique was used. Comparative estimation of elasticity and adhesive strength of hemostatic means, using tension testing machine “REM-10”, was fulfilled. Original polyurethane glue for medical purposes was developed and studied. Results. The glue compositions “Bioglue”, hemostatic sponge “Tachocomb” and original polyurethane composition for medical purposes with adhesive strength > 600 Pa (mm H2O) ( p < 0.05) possess the best adhesive properties. It was established on the basis of experimental data that the glue composition “Bioglue” and polyurethane glue composition have a high adhesive strength, elasticity and resistance to hydropression. Conclusions. 1. Glue compositions possess higher adhesion and endure higher level of pressure as compared with sponges and plates. Original polyurethane composition has maximum adhesive strength, elasticity and hydropression resistance. 2. After application of original polyurethane glue composition on resected liver (in experiment), it is completely lysed in 30-35 days.

Modification of a conventional polyurethane composition provides significant anti-biofilm activity against Escherichia coli

Tecoflex-NH3+ exhibited a contact-killing mechanism and showed excellent anti-biofilm properties against E. coli even after 5 days.

Use of liners made of concrete on quartz aggregates and polyurethane composition to reduce vibration, noise and improve the stability of tramway track

The theoretical basis of reduction of thermal deformations of the ballastless continuous welded track has been developed. The design of the track with integrated rails has been improved by using a special concrete liner of optimal composition with quartz fillers and aggregates and two-component polyurethane. The method of calculating the concrete composition with optimal strength and coefficient of linear thermal expansion together with optimal structural characteristics, To reduce the temperature stresses in the rails, liners should be made of concrete with quartz fillers and aggregates which provide a reduction of the coefficient of linear thermal expansion αL to 1.1×10-6 K-1. The analysis of the stressstrain state of the rails during heating, performed using the finite element method, has shown that the liners made of concrete with quartz aggregates decrease by 10-32% the temperature stresses in rails. The composition of concrete for liners with the compressive strength of above 60 MPa has been substantiated and the polyurethane composition has been selected for insulation of rails from the channel wall with adhesion to concrete of 0.7 MPa in a dry state, 0.43 MPa in a water-saturated state, and adhesion to steel of 1.2 MPa.

Compositional Designs for High Performance Antifingerprint Coated Concealed Cistern Control Panels

Concealed cistern control panels are the systems allowing the water inside the built-in reservoir to flow into the toilet bowl when it is necessary. In order to provide the water inside the reservoir to flush into the toilet bowl after the toilet is used, it is necessary to apply force on the control panels. Therefore, the panel surface is pressed with fingers. Especially in public places such as shopping malls, schools, hospitals; the sweat, oil and cosmetics passing through the fingers in a very short time leave spots on the panel surfaces. In order to clean the spots, it is needed to use cleaning materials with chemical content. This situation leads extra cost and as well as time consuming process. For this reason antifingerprint coated panels are required. In this study, antifingerprint coating systems were developed and to improve the coating performance such as mechanical and chemical resistance, different polyurethane composition ratios were studied and effectiveness of the coating systems were investigated by using characterization methods (SEM, EDX, FTIR).

Polycarbonate-based polyurethane elastomers: temperature-dependence of tensile properties

Novel polyurethane thermoplastic elastomers were prepared from polycarbonate diols, butane-1,4-diol (chain extender) and hexamethylene diisocyanate. They differ in the kind of macrodiol used and the ratio of macrodiol to chain extender OH groups (hence, in hard segment contents). The tensile properties of the elastomers at low and elevated temperatures were determined and discussed with regard to polyurethane composition and polycarbonate diol structure.