The objective of this study was to observe and evaluate the ability of innovative vascular prosthesis, made in Riga Technical University (RTU), to incorporate in a canine model. The research has been performed in Veterinary Medicine Faculty of Latvia University of Agriculture since July 19. 2011. The research was approved by the Food and Veterinary Service of the Republic of Latvia. The research is realized within the framework of European Social Fund co-financed project ‘Establishment of interdisciplinary research groups for new functional properties of smart textiles development and integrating in innovative products’ (ESF No 2009/0198/1DP/1.1.1.2.0./09/APIA/VIAA/148). RTU produced aortic grafts 5-8 mm in diameter and 8 mm to 18 mm long were implanted retroperitoneal in 9 female, 1-3 years old Beagle dogs. Once before and regularly after the surgery, abdominal aortic and vascular graft diameter was measured in cross sections. Blood pressure was measured before and regularly after the procedure. Results show no significant differences in aortic and graft diameter before and 12 months after the operation and there are no significant differences in systolic and diastolic blood pressure before and 6 months after the aortic surgery at a significance level α 0.05. The study shows that the innovative aortic prostheses do not change in diameter and abdominal aorta transplantation surgery does not cause significant variations in blood pressure. Study is continued to find out later reactions to synthetic vascular graft.

Two approaches to incorporating black alder (BA) bark extractives-derived polyol into a polyurethane (PU) network were studied. In the first case, fractionation of bark extractives with tetrahydrofuran (THF), focusing on isolating the biomass fraction available for obtaining PU elastomers by casting methods using cyclic ethers as a solvent, was employed. Another approach aimed to obtain liquid bio-polyols that could be suitable for producing rigid PU foams. For this purpose, oven-dried crude BA bark water extracts were liquefied with polyethylene glycol (PEG 400) at temperatures of 130–170 °C. The effect of adding sulfuric acid as a catalyst on biomass processing was studied. Wet chemistry, GC, FTIR spectroscopy, analytical pyrolysis (PyGC/MS/FID) and rheological methods were employed to characterize the obtained polyols and insoluble fractions, enabling an assessment of biomass transformation during processing. The resulting THF-soluble fraction comprised 62% of the BA bark extract, mainly consisting of the xyloside form of the diarylheptanoid compound oregonin, along with oligomeric flavonoids and carbohydrates. The THF-insoluble fraction was most enriched with carbohydrate compounds. Moreover, it was observed that the PEG 400-insoluble fractions were predominantly composed of carbohydrate components. The results indicated that the use of sulfuric acid as a catalyst (1–1.5% of solvent) promotes the complete liquefaction of extractives, enabling biomass content in polyols of up to 15–25%. Surpassing the extract content in the starting suspension up to 30% resulted in incomplete liquefaction of biomass. These findings offer valuable insights into tailoring BA bark extractives as building blocks suitable for obtaining PU materials.