Modeling of restenosis of main arteries after the intravascular stenting interventions

Objectives to study the mechanism of restenosis after the intra-arterial stenting using the original device for modeling of intra-arterial blood flow. Material and methods. To perform the experiment, we have created the original device simulating the intra-arterial blood flow. A glass tube of rotameter was the imitation of the arterial vessel. The closed system was filled with the liquid imitating blood, specifically the solution of glycerin the same viscosity as the human blood plasma. Using our original model of intra-artetial blood flow, we were able to study the intra-arterial hemodynamics under different conditions of cardiovascular system functioning, including arrhythmias. Results. In extrasystolic arrhythmia, during the spread of the first post-extrasystolic wave, we observed the intensive impact of pressure wave (the indicator was the silk thread) on the vessel walls with forming of reflected and standing waves. Putting the piezo crystal probe of pressure inside the tube, we verified our observations. The increase of pressure during the spread of the first post-extrasystolic wave in multiple measurements had a mean value of 160% in comparison with the pressure during the regular heart rhythm. Conclusion. The hydraulic shock appears during the spread of the first post-extrasystolic wave in the arterial vessel. Its effect on hemodynamics grows in case of the frequent extrasystoles and allorhythmia. The mechanical impact of hydraulic shock in extrasystoles can be the starting point of the restenosis onset and progressing in the intra-arterial stent

Evaluating the Effectiveness of Magnetic-Pulse Treatment for Healing Continuity Defects in the Metal of Oil and Gas Pipelines

This research paper addresses the issues in evaluating the effectiveness of magnetic-pulse treatment for healing continuity defects in the metal of oil and gas pipelines. A theoretical analysis of the magnetic-pulse action mechanism on continuity defects in the metal was carried out. The results of experimental studies of the effect of magnetic-pulse action on continuity defects of thick-walled samples, cut from used gas pipelines containing microcracks with different geometries, are also presented. The samples were processed under two different technological operating modes of the magnetic-pulse unit: the applied energy was 10 kJ for the first mode and 20 kJ for the second mode. The state of the cracks’ microstructure before and after the magnetic pulse treatment was studied using an optical microscope. As a result of the studies, it was found that magnetic-pulse treatment led to local heating of the crack tips, which was confirmed by the formation of a heat-affected zone in the vicinity of the crack tips. The temperature at the crack tips reached the metal’s melting point at the applied energy of 20 kJ, whereas at the energy of 10 kJ, signs of metal melting were not noted. In the course of the conducted experiments, it was found that the cracks were not completely eliminated after magnetic-pulse treatment; however, the edges of the crack tips melted, with subsequent filling by molten material. Magnetic-pulse treatment resulted in blunting of the crack tips, as their shape became smoother. It was established that the geometry and shape of the crack tip have significant influences on the effectiveness of this technology, as a narrow and sharp crack tip required less energy to reach the metal’s melting point compared to smoother one. The effect of magnetic pulse treatment on the microstructure of pipeline metal and its strength characteristics was also studied. It was found that this treatment leads to structural changes in the area of the crack tip in the form of grain refinement and subsequent strengthening of the pipeline metal

Genomic Predictors of Brisk Walking Are Associated with Elite Sprinter Status

Brisk walkers are physically more active, taller, have reduced body fat and greater physical fitness and muscle strength. The aim of our study was to determine whether genetic variants associated with increased walking pace were overrepresented in elite sprinters compared to controls. A total of 70 single-nucleotide polymorphisms (SNPs) previously identified in a genome-wide association study (GWAS) of self-reported walking pace in 450,967 European individuals were explored in relation to sprinter status. Genotyping of 137 Russian elite sprinters and 126 controls was performed using microarray technology. Favorable (i.e., high-speed-walking) alleles of 15 SNPs (FHL2 rs55680124 C, SLC39A8 rs13107325 C, E2F3 rs4134943 T, ZNF568 rs1667369 A, GDF5 rs143384 G, PPARG rs2920503 T, AUTS2 rs10452738 A, IGSF3 rs699785 A, CCT3 rs11548200 T, CRTAC1 rs2439823 A, ADAM15 rs11264302 G, C6orf106 rs205262 A, AKAP6 rs12883788 C, CRTC1 rs11881338 A, NRXN3 rs8011870 G) were identified as having positive associations with sprinter status (p IGSF3 rs699785 survived correction for multiple testing (p = 0.00004) and was linked (p = 0.042) with increased proportions of fast-twitch muscle fibers of m. vastus lateralis in physically active men (n = 67). Polygenic analysis revealed that individuals with ≥18 favorable alleles of the 15 SNPs have an increased odds ratio of being an elite sprinter when compared to those with ≤17 alleles (OR: 7.89; p < 0.0001). Using UK Biobank data, we also established the association of 14 favorable alleles with low BMI and fat percentage, 8 alleles with increased handgrip strength, and 7 alleles with increased height and fat-free mass. In conclusion, we have identified 15 new genetic markers associated with sprinter status