International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Almost half of all known to date proteins contain metal co-factors. Over the course of 3–4 billion years of organism evolution, several metal species of different oxidation state (Na+, K+, Mg2+, Ca2+, Zn2+, Mn2+, Fe2+/3+, Co2+/3+, Ni2+ and Cu+/2+) have been chosen to participate in key biological processes. They are known as “native”, or “biogenic” metals. On the other end stand toxins like mercury and lead, which poison the recipient by competing with the natural co-factors for binding the essential proteins. As a third example, however, should be outlined some abiogenic metal species, which exert a curative effect on the host organism, and are, therefore, applied in medicine as novel drugs. Such are silver (Ag+), strontium (Sr2+), and gallium (Ga3+). The current study investigates their ability to compete with the native cuprous (Cu+), calcium (Ca2+), and ferric (Fe3+) cations, respectively, by exploiting the methods of the computational chemistry. Nowadays, silver finds broad application in many areas of medicinal use, e.g. being added to dressings of burn wounds as a concomitant therapy of skin ulcers, as a potential water disinfectant, or even in ophthalmology as an active component in eye drops. Strontium prevents the destruction of bones and contributes to their restoration. Sr2+ salt of ranelic acid is a medication (under the names Protelos, Protos, Strontium ranelate Aristo) used for treatment of osteoporosis in postmenopausal women and very elderly patients. Gallium, in its cationic form (Ga3+), is well known for its anticancer activity. Nonetheless, recent experimental studies have considered the employment of gallium as a promising “Trojan horse” strategy against pathogenic microorganisms. Herewith, we set on a quest for deciphering the most acclaimed mechanisms of therapeutic action of the aforementioned metal cations at atomic level. The obtained results shed light on the intimate echanisms of metal recognition, thus revealing key factors governing the processes of native/abiogenic metal rivalry. This approach serves not only for explaining already existing experimental findings, but also as a first step in designing/engineering novel drug molecules of potential therapeutic value.

The market of precious metals in the world is studied. The requirements for the standard of gold, silver and platinum ingots are named. Factors influencing the world market of precious metals are revealed. Forms of market organization are described. The dynamics of gold, silver, platinum and palladium production in 2010 – 2019 are given. The tendencies of development of the world market of precious metals and the market of precious metals in Ukraine are named

In this work, the influence of addition of polyvinylpyrrolidone (PVP, 10kDa, 1-4.8wt%) and Ag-modified titanate nanotubes (Ag/TNTs, 0.1wt%) on physicochemical and transport properties of polyethersulfone (PES) ultrafiltration membranes was studied. The membranes were prepared via wet phase inversion method using N,N-dimethylformamide (DMF) as a solvent and water as a non-solvent. The Ag/TNTs nanocomposite was obtained via photodeposition method using AgNO3 as a precursor. It was found that the addition of PVP into the casting dope affected the cross-section structure of the membranes and their surface topography. The presence of PVP improved the dispersion Ag/TNTs agglomerates in the membranes structure. A positive influence of the introduction of the nanocomposite into the membranes matrix on their permeability was also proved.

Electrochemical behavior of silver in tungstate-molybdate melts was studied by potentiometric and voltammetric methods. The electrode process was identified as a single-electron reversible one. The effect of silver on the electrochemical deposition of molybdenum carbide coatings and their electrochemical corrosion behavior in a sodium polysulfide melt was studied.