Teodor Tóth

Alterations in the rabbit lymphoid tissue after bendiocarb administration.

Various pesticides have immuno-suppressive effects, and thus the organisms become responsive to viral, bacterial and parasitic diseases and neoplasm. The aim of the study was to observe the structure of the small intestine (height of enterocytes and crypts), mucosal lymphoid tissue (Payers patches, lymphocytes in lamina propria) and a lymph node after administration of bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-yl-methylcarbamate) on days 3, 10, 20, 30 and 60 of the experiment. The height of the observed enterocytes showed an increasing tendency. On days 20, 30 and 60 we also observed an increase in diameter of crypts located in intestinal epithelium. The number of cells in lamina propria mucosae was significantly reduced on days 20 and 30 after administration of bendiocarb. Observations of the lymph node showed that on days 10 and 20 there was a significant increase in relative volume of medulla at the expense of the relative volume of the cortex and a decrease in the number of lymphocytes. However, we recorded an increase in diameter of lymphocytes. The intracellular parasite Toxoplasma gondii (T. gondii) belongs to the most common pathogenic parasites in the world and it can cause serious health complications in pregnant and immunodeficient individuals. DNA isolation, standard polymerase chain reaction (PCR) and visualization in a 2.5 % agarose gel, the presence of DNA T. gondii was detected in no examined rabbit brain samples. Using real time PCR T. gondii DNA was detected and quantified in the three rabbit brain samples (10 %).

Embedded Tensile Strenght Test Machine FM1000 – An Upgrade of Measurement and Control

In order to compare the strengths of various materials it is necessary to carry out a standard form of test to establish their relative properties. The tensile test, compression test, bending, shearing and torsion tests are used for examining mechanical properties of biological materials. Except for non-destructive methods (optical, electromagnetic, sonic, thermal, infrared), destructive testing is another very important tool for the assessment of biomechanical properties and behavior of biomedical materials. The tensile strength test is one of the most common testing methods, which uses specific testing machines. Many tensile testing machines are equipped to plot a curve which shows the load or stress and the strain or movement that occurs during the test operation. In the testing operation, the load is increased gradually and the specimen will stretch or elongate in proportion to the tensile load. The load cells and extensometers measure the key parameters of force and deformation. The presented paper is a report which describes a specific and unique technical solution and upgrade of FM 1000 machine from the control and output processing point of view. Modern sensoric systems and I/O modules were used and custom software was developed. The fu

Usage of Industrial Computed Tomography for Evaluation of Custom-Made Implants

Development of additive technologies and biocompatible materials facilitated their use in the custom-made implants manufacture. Verification of custom-made implants manufactured using the additive manufacturing technologies is the key task to be fulfilled prior to the clinical application of an implant. It consists of parameters verification within individual steps, from a software design, through manufacturing, surface finishing, up to finalization of a medical product. The article presents possible uses of a 3D printing and the computed tomography (Metrotom 1500, Carl Zeiss, Germany) for the verification of selected parameters of customized implants manufactured using the Direct Metal Laser Sintering (DMLS) technology with the EOSINT M280 equipment (EOS GmbH, Germany) from the biocompatible titanium alloy Ti-6Al-4V (Grade 5). The article describes the possibilities of the computed tomography use in the verification of implant shapes and external dimensions, as well as internal structure. The internal structure means the implant porosity assessment.

Rat skin wounds tensile strength measurements in the process of healing

The goal of our investigation was to evaluate mechanical properties of the skin wounds during the first seven days of primary healing. We realized two parallel symmetrical skin incision (on the left and right side of the spine) in the general anaesthesia. Rats were divided into 7 groups. We measured tensile strength of the wound in 24, 48, 72, 96, 120, 144 and 168 hours after wounding in every group. After each day of measurement we obtained complex of tensile strength diagrams of wound tensile strength-time dependence. We observed the highest absolute strength increase after 24 hours within 5 days after wounding. In the period between 2nd and 5th day of testing we observed stagnation of the strength, labelled as “plató phase”. Next significant strength increase was observed only after 6 days, with following increase of the tensile strength of skin wound.

Failure analysis of conveyor belt samples under tensile load

This paper is dedicated to investigating the properties of smooth conveyor belts through a tensile loading test, with the aim of examining the behavior of the inner structure of the belt samples. When the belt is subjected to a long-term strain, the belt relaxation effect is observed and changes may occur to the inner structure of the belt. The tensile test at constant velocity determines the load strength limit of the strip samples. The experiment has also shown the phenomenon of relaxation of the samples after the load. Metro-tomographic analysis is used to observe the behavior of the internal structure of the belt sample after the load. The obtained results indicate the initial damage of the inner structure of the conveyor belt occurred at the value of 2157 N. Under this load, the maximum damage size was 4.8 mm. This confirms the suitability of the method for tracking changes in the internal structure.

Analysis of defects in carcass of rubber–textile conveyor belts using metrotomography:

Rubber–textile construction of conveyor belts is widely used in various continuous transport systems. Due to the fact that complex carcass is vulcanised, its observation and analysis are very difficult to perform. The methods used so far have been based on its violent extracting, often accompanied with the formation and existence of defects. Such an analysis does not allow distinguishing between defects caused by operation of the belt or defects caused by the process of extracting itself. This paper aims to verify a new approach to examining the inner carcass of rubber–textile conveyor belts with a focus on the possibility to obtain information about its condition. This has not been possible with the methods used so far. The main focus is on the measurement of distance between the individual fibres in the warp and weft of the carcass, and simple size analysis of the identified defects. Presented results prove that the method of industrial tomography clearly identifies the defects in the conveyor belt carcass. The method enables the identification of single fibres, punctures and separation of individual layers.

Influences of Surface Determination for Measurements Obtained by Industrial Computed Tomography

At present emphasis is placed on input or output control of products in the manufacturing process. One of the criteria is the dimensional analysis or porosity analysis of products. In the case that products are of complicated shapes, or measurements are to be taken in places which are not accessible to standard measuring devices (manual measurements, coordinate measuring machines) the use of computed tomography is one of the possibilities for obtaining the desired dimensions. These technologies work with digital data and therefore the surfaces which are to be assessed must be created on the basis of determined criteria. Surface determination is one of the most important settings during the evaluation of the visual shape (state) of a surface and assessing dimensions. During such evaluation this is the main parameter which globally influences the precision of the obtained data. In the case of an unsuitably determined surface the obtained results can vary from reality even by several tenths of a millimeter depending on the scanned object and the scanning conditions. The conveyor belts are composed of two or more materials with different densities, such as rubber and textile fibers. In cooperation with Faculty of Mining, Ecology, Process Control and Geotechnology is tested and evaluated the effect of the impactor with various energy into conveyor belt. The correct surface determination for selected material is necessary to evaluate the dimensions, the damage and pores. The article deals with the impact of surface determination on the result of a measurement.

Determination of geometrical and viscoelastic properties of PLA/PHB samples made by additive manufacturing for urethral substitution

Additive manufacturing has a great potential for creating hard tissue substitutes, such as bone and cartilage, or soft tissues, such as vascular and skin grafts. This study is a pilot study for 3D printing of a new material mixture potentially used as a tubular substitute for urethra replacement. This new mixture is a blend of polylactic acid (PLA) and polyhydroxybutyrate (PHB). The basic aspect that affects the 3D printing process is correct material preparation and setting of 3D printer parameters. Selection of material and printing parameters depend on printing technology. The printing technology affects material behavior during printing process. The goal of preprocessing and 3D printing process is to provide stabile conditions during manufacturing to obtain usable printed samples. The study deals with preparation of material before 3D printing - material drying. Moisture in material affects material degradation and viscosity during printing. According to this, it is necessary to verify recommended drying parameters. Verification was performed by printing strand samples from dried and non-dried material and also by calculating and comparing respective viscosities that change in time. Printed strand clearly show that non-dried material degrades in less than 10 min, what leads to inappropriate application in short-time printing. Dried material shows significant stability and degrades slightly during selected time span. For metrological verification of material stability two sample types were designed and manufactured - a cubic sample which represents basic scaffold structures and a tubular one that serves as urethra substitution. Obtained results showed appropriate usability of selected technology and printing parameters for PLA / PHB material blend.

Analysis of inclusions at materials by metrotomography

The aim of this work is to analyze inclusions of samples from selected materials using metrotomography. The main part of the problem was correct methodology of software processing of the measured data acquired by computed tomography equipment Carl Zeiss METROTOM1500. For various settings of the input parameters was investigated expected output data to a known set of defects. Comparison of the effects of setting on results of the assessment should help in setting parameters for evaluation of defects in industrial applications.

EMG system application in muscle parametrization of the upper extremities

In order to understand diseases regarding the musculoskeletal system, it is necessary to be familiar with the basic laws of the physiology of movement and individual morphological structures that create this movement. The presented article deals with the methodology of scanning and processing electrical processes in a muscle. In order to determine pathological state, expert knowledge is needed and due to this fact, the objective of this study was determination of behaviour of muscle groups of the upper extremity before and after load application in healthy population. The electromyographic system serves this purpose and it enables to scan the electrical muscle changes. The device BTS FREEEMG 300 was used for measuring, using a principle of surface electromyography. Obtained signal was then processed in the Matlab programme and the acquired values were evaluated by using a significance test of two variables.