The physical synthesis of iron oxide nanoparticles obtained from the vapor phase using the electron beam physical vapor deposition method is considered. The results of studying the structure of porous condensates of iron-sodium chloride compound, chemical and phase compositions, as well as nanoparticles size are presented. With a rapid removal from vacuum, iron nanoparticles are oxidized in the air to magnetite. In the initial state, they have significant sorption capacity with respect to oxygen and moisture, therefore, with further heating in the air, the porous condensate mass decreases up to the temperature 650 °C, primarily due to the desorption of physically sorbed moisture. Physically adsorbed oxygen participates in oxidation of Fe 3 O 4-Fe 2 O 3 in the range of 380-650 °C. An increase in condensation temperature is accompanied by an increase of nanoparticle size, as a result of which the total surface area of nanoparticles is significantly reduced, and, consequently, their sorption capacity is decreased. Even without stabilization, such nanoparticles studied as ex tempore prepared aqueous dispersion have characteristic anti-anemic effect in the laboratory animals that can be used in medicine. Keywords EB-PVD • Iron oxide nanoparticles • Sorption • Phase composition • Colloid systems • Anti-anemic effect Abbreviations DLS Dynamic light scattering DTA Differential thermal analysis EB-PVD Electron beam physical vapor deposition EDS Energy-dispersive X-ray spectroscopy Fe 3 O 4 Magnetite, iron(II, III) oxide
Background. S. warneri is a common commensal organism, but it can cause serious infections. One of the ways to increase a susceptibility of this microorganism to antibiotics is their combining with adjuvant remedies.
Objectives. The aim of the research is to study the susceptibility of S. warneri clinical isolate to antibiotics and its modification by emoxypine - 2-ethyl-6-methyl-3-hydroxypyridine hydrochloride.
Methods. Samples of purulent wound exudation were obtained from a patient with infective complications after a bone fracture and osteosynthesis by metal plates. Susceptibility of S. warneri clinical isolate to antibiotics and their combinations with emoxypine (1000 μg/disk) was studied by a standard disc diffusion technique. In the case of microbial resistance, the susceptibility of the investigated isolate to such antibiotic was determined by a serial broth dilutions method without or with emoxypine and evaluated according to the minimum inhibitory concentration (MIC).
Results. By the disk diffusion method, S. warneri isolate was susceptible to all tested antibiotics, except chloramphenicol. The growth inhibition zones also were formed around disks containing emoxypine, but the susceptibility of S. warneri to this agent was low. Applying of emoxypine on the disks with antibiotics resulted in the increase of S. warneri growth inhibition in all cases, except using the amikacin, gentamicin, and fusidic acid. The most significant changes were evidenced for a composition chloramphenicol / emoxypine. Using chloramphenicol alone in the liquid medium, the MIC was over a cut-off point. Adding of emoxypine (209 μg/ml) decreased the MIC of the antibiotic and restored the susceptibility S. warneri to chloramphenicol.
Conclusions. The susceptibility of S. warneri clinical isolate to antibiotics can be increased by combining with emoxypine, which among other overcomes the resistance of the studied microorganism to chloramphenicol.
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