The musculoskeletal system, consisting of bones and cartilage of various types, muscles, ligaments, and tendons, is the basis of the human body. However, many pathological conditions caused by aging, lifestyle, disease, or trauma can damage its elements and lead to severe disfunction and significant worsening in the quality of life. Due to its structure and function, articular (hyaline) cartilage is the most susceptible to damage. Articular cartilage is a non-vascular tissue with constrained self-regeneration capabilities. Additionally, treatment methods, which have proven efficacy in stopping its degradation and promoting regeneration, still do not exist. Conservative treatment and physical therapy only relieve the symptoms associated with cartilage destruction, and traditional surgical interventions to repair defects or endoprosthetics are not without serious drawbacks. Thus, articular cartilage damage remains an urgent and actual problem requiring the development of new treatment approaches. The emergence of biofabrication technologies, including three-dimensional (3D) bioprinting, at the end of the 20th century, allowed reconstructive interventions to get a second wind. Three-dimensional bioprinting creates volume constraints that mimic the structure and function of natural tissue due to the combinations of biomaterials, living cells, and signal molecules to create. In our case—hyaline cartilage. Several approaches to articular cartilage biofabrication have been developed to date, including the promising technology of 3D bioprinting. This review represents the main achievements of such research direction and describes the technological processes and the necessary biomaterials, cell cultures, and signal molecules. Special attention is given to the basic materials for 3D bioprinting—hydrogels and bioinks, as well as the biopolymers underlying the indicated products.

A set of nonlinear differential equations for calculation of the gas flow parameters in a plasmatron barrel is derived. Comparison between the data obtained by integrating this set and a numerical...

Aim. As neurogenic processes affect the cardiovascular system and change its function throughout the whole life, the study aims to simulate and study the hydrodynamics of blood flow in an intact and denervated aorta.Methods. A pulse wave going through an intact segment of a dog’s thoracic aorta, a denervated autograft, and a donor dog’s thoracic aorta allograft was assessed by using equipment for blood pressure measurement and tensiometry of longitudinal and diametrical deformations of blood vessels at the point of pressure measuring. The experiments were performed under general endotracheal anesthesia. Two series of acute experiments on replacement of the thoracic aorta by an autograft and an allograft were carried out. Each series had eight dogs. The approach was thoracotomy in the IV intercostal space on the left. A required segment was replaced after heparin infusion while using subclavian-femoral bypass and retrograde autoperfusion.Results. It was found out experimentally that the formation and propagation of a normal isolated pulse wave with preservation of a viscous laminar blood flow were impossible without preserved innervation of the aorta. The experiments showed that in an intact aorta, its diameter tends to increase (by 400–500 μm), with simultaneous shortening of the segment (by 250 μm), and this process keeps being ahead of the pressure wave by 0.02–0.04 s. The rate of aortic dilatation is faster than that of systolic pressure elevation. However, in contrast to the intact aorta, the autograft, on the contrary, becomes longer and narrows, as pressure rises.Conclusion. To create optimal hydrodynamics of aortic blood flow, there should be a neuroreflectory system to control each pulse wave, which must determine its solitonic nature and provide antiflatter stabilization of blood flow.Received 16 April 2018. Revised 3 June 2018. Accepted 7 June 2018.Funding: The study did not have sponsorship.Conflict of interest: The authors declare no conflict of interest.

An alternative, nonelectrical method for obtaining a dense radiating plasma and the possibilities of using this method to pump solid-state lasers are investigated. The plasma was obtained...