Covalently linked porphyrin–quinone model systems for photosynthetic electron transfer were examined by using time-resolved electron paramagnetic resonance (TREPR) at intermediate magnetic field and microwave frequency (0.34T/9.5GHz, X-band) and high field and frequency (3.4T/95GHz, W-band). The paramagnetic transients studied were the light-induced spin-correlated radical pair states of the donor–acceptor complex in polar solvents below the melting point and in the soft glass phase of a liquid crystal. It is shown that the systems form strongly exchange-coupled radical pairs, whose TREPR lineshapes are determined mainly by fast electron recombination together with both spin–lattice relaxation and modulation of the exchange interaction. Below the melting point the spin–lattice relaxation rate naturally slows down, but that of the spin on the quinone site is still of the order of 10⁶ s^-1. Most probably this is due to contributions from spin–rotation interaction, and dependent on the molecular orientation with respect to the magnetic field. This relaxation anisotropy is related to anisotropic motion of the quinone site in the solvent cage. The results allow conclusions to be drawn concerning the molecular dynamics and flexibility of the systems. To yield long-lived radical pair states that would mimic photosynthetic electron transfer, the two mechanisms described, modulation of exchange and spin–rotation interactions, have to be suppressed by reducing the molecular flexibility of the complex.

The gastrointestinal microflora regulates the body’s functions and plays an important role in its health. Dysbiosis leads to a number of chronic diseases such as diabetes, obesity, inflammation, atherosclerosis, etc. However, these diseases can be prevented by using probiotics – living microorganisms that benefit the microflora and, therefore, improve the host organism's health. The most common probiotics include lactic acid bacteria of the Bifidobacterium and Propionibacterium genera. We studied the probiotic properties of the following strains: Bifidobacterium adolescentis АС-1909, Bifidobacterium longum infantis АС-1912, Propionibacterium jensenii В-6085, Propionibacterium freudenreichii В-11921, Propionibacterium thoenii В-6082, and Propionibacterium acidipropionici В-5723. Antimicrobial activity was determined by the ‘agar blocks’ method against the following test cultures: Escherichia coli ATCC 25922, Salmonella enterica ATCC 14028, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa B6643, Proteus vulgaris ATCC 63, and Listeria monocytogenes ATCC 7644. Moderate antimicrobial activity against all the test cultures was registered in Bifidobacterium adolescentis АС-1909, Propionibacterium jensenii В-6085, and Propionibacterium thoenii В-6082. Antioxidant activity was determined by the DPPH inhibition method in all the lactic acid strains. Our study indicated that some Propionibacterium and Bifidobacterium strains or, theoretically, their consortia could be used as probiotic cultures in dietary supplements or functional foods to prevent a number of chronic diseases.

Introduction. Meat processing enterprises are facing the problem of utilization of secondary products with a limited scope of application and a wide range of useful properties. One of the promising ways of slaughter-house by-product utilization is the production of biomaterials that can replace various tissues of a living organism. This review presents an analysis of the global biomaterials market, its volume, and possible ways of using secondary meat resources in various sectors of economy. Study objects and methods. The article represents some results of a desk research based on open sources, i.e. publications and Internet data portals. Results and discussion. One of the most important tasks of modern regenerative medicine is to develop fast and effective methods for the restoration of damaged or lost organs and tissue fragments. Its solution directly depends on new advanced biomaterials. Modern biocompatible materials are in great demand in such areas of medicine as orthopedics, ophthalmology, dentistry, general and cardiovascular surgery, restorative medicine, drug delivery, etc. Cosmetology is a rapidly evolving segment of medicine and depends on such biomaterials as hyaluronic acid and collagen. Russian biomedicine occupies 0.7% of the world market. However, the Russian segment is likely to grow and expand its range of biomaterials. Conclusion. The currently unused resources of meat industry can be an excellent source of valuable raw materials for the advanced biomedical structures used in tissue engineering. A wide variety of structures and properties of secondary resources can produce a wide range of biomaterials. The possibility of manufacturing matrices from internally sourced raw materials within one enterprise is particularly promising.

Hyperthermia therapy (HT) is becoming a well-recognized method for the treatment of cancer when combined with radiation or chemotherapy. There are many ways to heat a tumor and the optimum approach depends on the treatment site. This study investigates a composite ferromagnetic surgical implant inserted in a tumor bed for the delivery of local HT. Heating of the implant is achieved by inductively coupling energy from an external magnetic field of sub-megahertz frequency. Implants are formed by mechanically filling a resected tumor bed with self-polymerizing plastic mass mixed with small ferromagnetic thermoseeds. Model implants were manufactured and then heated in a 35 cm-diameter induction coil of our own design. Experimental results showed that implants were easily heated to temperatures that allow either traditional HT (39 °C-45 °C) or thermal ablation therapy (>50 °C) in an external magnetic field with a frequency of 90 kHz and amplitude not exceeding 4 kA/m. These results agreed well with a numerical solution of combined electromagnetic and heat transfer equations solved using the finite-element method.