Biodegradable polymers are materials that, thanks to their remarkable properties, are widely understood to be suitable for use in scientific fields such as tissue engineering and materials engineering. Due to the alarming increase in the number of diagnosed diseases and conditions, polymers are of great interest in biomedical applications especially. The use of biodegradable polymers in biomedicine is constantly expanding. The application of new techniques or the improvement of existing ones makes it possible to produce materials with desired properties, such as mechanical strength, controlled degradation time and rate and antibacterial and antimicrobial properties. In addition, these materials can take virtually unlimited shapes as a result of appropriate design. This is additionally desirable when it is necessary to develop new structures that support or restore the proper functioning of systems in the body.

Hydrogels from natural polymers such as sodium alginate have great potential in regenerative medicine because of their biocompatibility, biodegradability, mechanical properties, bioresorption ability, and relatively low cost. Sodium alginate, a polysaccharide derived from brown seaweed, is the most widely investigated and used biomaterial in biomedical applications. Alginate dressings are also useful as a delivery platform in order to provide a controlled release of therapeutic substances (e.g., pain-relieving, antibacterial, and anti-inflammatory agents). In our work, we aimed to analyze process of degradation of alginate hydrogels. We also describe an original hybrid crosslinking process by using not one, as usual, but a mixture of two crosslinking agents (calcium chloride and barium chloride). We proved that different crosslinking agents allow producing hydrogels with a spectrum of mechanical properties, similar to the urethra tissue. Hydrogels were formed using a dip-coating technique, and then examined by mechanical testing, FTIR (Fourier-Transform Infrared Spectroscopy), and resorption on artificial urine. Obtained hydrogels have a different degradation rate in artificial urine, and they can be used as a material for healing of urethra injuries, especially urethra strictures, which significantly affect the quality of life of patients.

The search for ideal solutions for the treatment of urethral stenosis continues. This includes developing the material, design, while maintaining its optimal and desired properties. This paper presents the results of the research conducted on sodium alginate-based hydrogel material (AHM), which may be used as a material for stents dedicated to the treatment of pathologies occurring in the genitourinary system. In order to determine the selected parameters of the AHM samples, strength and degradation tests, as well as analysis of the micro changes occurring on the surface of the material using a digital image correlation (µDIC) system, were performed. This study shows that the material possessed good mechanical strength parameters, the knowledge of which is particularly important from the point of view of the stent-tissue interaction. The degradation analysis performed showed that the AHM samples degrade in an artificial urine environment, and that the degradation time mainly depends on the chemical composition of the material. The novel µDIC method performed allowed us to characterize the homogeneity of the material structure depending on the cross-linking agent used.

Civilization and technical progress are not possible without energy. Dynamic economic growth translates into a systematic increase in demand for electricity. Ensuring the continuity and reliability of electricity supplies is one of the most important aspects of energy security in highly developed countries. Growing energy consumption results not only in the need to build new power plants but also in the need to expand and increase transmission capacity. Therefore, large quantities of electric cables are produced all over the world, and after some time, they largely become waste. Recycling of electric cables focuses on the recovery of metals, mainly copper and aluminum, while polymer insulation is often considered waste and ends up in landfills. Currently, more and more stringent regulations are being introduced, mainly environmental ones, which require maximizing the reduction in waste. This article provides a literature review on cable recycling, presenting the advantages and disadvantages of various recycling methods, including mechanical and material recycling. It has been found that currently, there are very large possibilities for recycling cables, and intensive scientific work is being carried out on their development, which is consistent with global climate policy.

New hydrogel materials developed to improve soft tissue healing are an alternative for medical applications, such as tissue regeneration or enhancing the biotolerance effect in the tissue-implant–body fluid system. The biggest advantages of hydrogel materials are the presence of a large amount of water and a polymeric structure that corresponds to the extracellular matrix, which allows to create healing conditions similar to physiological ones. The present work deals with the change in mechanical properties of sodium alginate mixed with gelatin containing Pygeum africanum. The work primarily concentrates on the evaluation of the mechanical properties of the hydrogel materials produced by the sol–gel method. The antimicrobial activity of the hydrogels was investigated based on the population growth dynamics of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923, as well as the degree of degradation after contact with urine using an innovative method with a urine flow simulation stand. On the basis of mechanical tests, it was found that sodium alginate-based hydrogels with gelatin showed weaker mechanical properties than without the additive. In addition, gelatin accelerates the degradation process of the produced hydrogel materials. Antimicrobial studies have shown that the presence of African plum bark extract in the hydrogel enhances the inhibitory effect on Gram-positive and Gram-negative bacteria. The research topic was considered due to the increased demand from patients for medical devices to promote healing of urethral epithelial injuries in order to prevent the formation of urethral strictures.

Background: Frequency of urethral stenosis makes it necessary to develop new innovative methods of treating this disease. This pathology most often occurs in men and manifests itself in painful urination, reduced urine flow, or total urinary retention. This is a condition that requires immediate medical intervention. Methods: Experimental tests were carried out on a rabbit in order to determine the changes of pressure in the urethra system and to estimate the velocity of urine flow. For this purpose, a measuring system was proposed to measure the pressure of a fluid-filled urethra. A fluoroscope was used to observe the deformability of the bladder and urethra canal. Results: Based on these tests, the range of changes in the urethra tube diameter, the pressures inside the system, and the flow velocity during micturition were determined. Conclusions: The presented studies allowed determining the behavior of the urethra under the conditions of urinary filling. The fluid-filled bladder and urethra increased their dimensions significantly. Such large changes require that the stents used for the treatment of urethral stenosis should not have a fixed diameter but should adapt to changing urethral dimensions.