•Biopolymer layer-by-layer nanocoatings change the surface properties of nitinol plates.•Using κ-carrageenan as the top layer reduces hydrophobicity and surface roughness.•The use of chitosan as the ...lower layer of the film allows increasing the stability polymer coatings on the nitinol.•Chitosan/carrageenan films that were applied to nitinol plates reduce cytotoxicity in relation to the MG-63 cells line.
Thin films based on the natural polysaccharides κ-carrageenan (Carr) and chitosan (Chit) were formed by layer-by-layer deposition technique. Surface topography and mechanical characteristics (Young's modulus, adhesion strength) of the polymer films with different number of layers were determined using various modes of atomic force microscopy (AFM). Polymer films were used to deposit on the surface of nitinol (NiTi) plates. The creation of polysaccharide coatings on nitinol led to a change in surface properties, such as hydrophilicity and root mean square roughness. in vitro cytotoxicity assay for nitinol plates with and without polymer coating by the MG-63 osteoblast-like cell line was conducted and was shown that all the studied samples are not toxic. A decrease in cytotoxicity for samples with a polymer film consisting of 4 layers of chitosan and carrageenan was shown as compared to an uncoated nitinol plates.
Bioprinting can be defined as additive biofabrication of three-dimensional (3D) tissues and organ constructs using tissue spheroids, capable of self-assembly, as building blocks. The thyroid gland, a ...relatively simple endocrine organ, is suitable for testing the proposed bioprinting technology. Here we report the bioprinting of a functional vascularized mouse thyroid gland construct from embryonic tissue spheroids as a proof of concept. Based on the self-assembly principle, we generated thyroid tissue starting from thyroid spheroids (TS) and allantoic spheroids (AS) as a source of thyrocytes and endothelial cells (EC), respectively. Inspired by mathematical modeling of spheroid fusion, we used an original 3D bioprinter to print TS in close association with AS within a collagen hydrogel. During the culture, closely placed embryonic tissue spheroids fused into a single integral construct, EC from AS invaded and vascularized TS, and epithelial cells from the TS progressively formed follicles. In this experimental setting, we observed formation of a capillary network around follicular cells, as observed during in utero thyroid development when thyroid epithelium controls the recruitment, invasion and expansion of EC around follicles. To prove that EC from AS are responsible for vascularization of the thyroid gland construct, we depleted endogenous EC from TS before bioprinting. EC from AS completely revascularized depleted thyroid tissue. The cultured bioprinted construct was functional as it could normalize blood thyroxine levels and body temperature after grafting under the kidney capsule of hypothyroid mice. Bioprinting of functional vascularized mouse thyroid gland construct represents a further advance in bioprinting technology, exploring the self-assembling properties of tissue spheroids.
The article presents the results of improving the numerical method developed in 1-3 for calculating the roughness coefficient of the riverbed (RCOTR) to increase stability and using it to study the ...dependence of the RCOTR of the Instruch River on dimensionless complexes in different seasons.
Abstract The potential probiotic yeast was isolated from the Kyzyl Anor pomegranate variety growing in the Turkestan region (Kazakhstan). The yeast strain was identified as Saccharomyces cerevisiae ...Az-12. Molecular genetic identification was carried out using the Sanger sequencing method. The degree of homology of the S. cerevisiae Az-12 strain with the strain MH608341.1 Saccharomyces cerevisiae isolate extr03 was 99.65%. Antagonistic effect of the yeast against pathogenic bacteria was confirmed according inhibition zones for Staphylococcus aureus 13.5 ± 0.05 mm; the inhibition zones for Escherichia coli 12.8 ± 0.05 mm; and 10.7 ± 0.05 mm for Pseudomonas aeruginosa. Scanning microscopy of S. cerevisiae Az-12 and S. aureus confirmed the adhesive ability of the yeast cell surface to S. aureus. S. cerevisiae Az-12 were chosen as the most promising, as they are able to quickly ferment juices. Functional drinks containing pomegranate juice and yeast with a probiotic effect can be considered as a useful synbiotic product formulation.
Resumo A levedura probiótica potencial foi compreendida da variedade de romã Kyzyl Anor que cresce na região do Turquestão (Cazaquistão). A cepa de levedura foi identificada como Saccharomyces cerevisiae Az-12. A identificação genética molecular foi realizada pelo método de sequenciamento de Sanger. O grau de homologia da cepa S. cerevisiae Az-12 com a cepa MH608341.1 Saccharomyces cerevisiae isolado extr-03 foi de 99,65%. O efeito antagônico da levedura contra bactérias patogênicas foi confirmado de acordo com as zonas de inibição para Staphylococcus aureus 13,5 ± 0,05 mm; as zonas de inibição para Escherichia coli 12,8 ± 0,05 mm; e 10,7 ± 0,05 mm para Pseudomonas aeruginosa. A microscopia de varredura de S. cerevisiae Az-12 e S. aureus confirmou a capacidade de adesão da superfície celular de levedura a S. aureus. S. cerevisiae Az-12 foram escolhidas como as mais promissoras, pois são capazes de fermentar sucos rapidamente. Bebidas funcionais contendo suco de romã e fermento com efeito probiótico podem ser consideradas como uma formulação de produto simbiótico útil.
Abstract
The natural flow regulation coefficient is used in solving engineering and scientific problems in the field of hydrology, hydraulic engineering. The article presents the results of ...calculating this coefficient for the rivers of the Kaliningrad region based on the results of observations. The previously developed calculation method in the Mathcad environment was used. The range of changes in the coefficient of natural regulation of the flow of rivers in the Kaliningrad region significantly exceeds the similar range given for the rivers of the North-West of Russia. The closest stochastic relationship is in the coefficient of natural regulation of river flow in the Kaliningrad region with 30-day water discharges.
Calcium phosphate cements are of great interest for researchers and their applications in medical practice expanded. Nevertheless, they have a number of drawbacks including the insufficient level of ...mechanical properties and low degradation rate. Struvite (MgNH
PO
) -based cements, which grew in popularity in recent years, despite their neutral pH and acceptable mechanical performance, release undesirable NH
ions during their resorption. This issue could be avoided by replacement of ammonia ions in the cement liquid with sodium, however, such cements have a pH values of 9-10, leading to cytotoxicity. Thus, the main goal of this investigation is to optimize the composition of cements to achieve the combination of desirable properties: neutral pH, sufficient mechanical properties, and the absence of cytotoxicity, applying Na
HPO
-based cement liquid. For this purpose, cement powders precursors in the CaO-MgO-P
O
system were synthesized by one-pot process in a wide composition range, and their properties were investigated. The optimal performance was observed for the cements with (Ca + Mg)/P ratio of 1.67, which are characterized by newberyite phase formation during setting reaction, pH values close to 7, sufficient compressive strength up to 22 ± 3 MPa (for 20 mol.% of Mg), dense microstructure and adequate matrix properties of the surface. This set of features make those materials promising candidates for medical applications.
Calcium phosphate cements are of great interest for researchers and their applications in medical practice expanded. Nevertheless, they have a number of drawbacks including the insufficient level of ...mechanical properties and low degradation rate. Struvite (MgNH4PO4) -based cements, which grew in popularity in recent years, despite their neutral pH and acceptable mechanical performance, release undesirable NH4+ ions during their resorption. This issue could be avoided by replacement of ammonia ions in the cement liquid with sodium, however, such cements have a pH values of 9–10, leading to cytotoxicity.
Thus, the main goal of this investigation is to optimize the composition of cements to achieve the combination of desirable properties: neutral pH, sufficient mechanical properties, and the absence of cytotoxicity, applying Na2HPO4-based cement liquid. For this purpose, cement powders precursors in the CaO–MgO–P2O5 system were synthesized by one-pot process in a wide composition range, and their properties were investigated.
The optimal performance was observed for the cements with (Ca + Mg)/P ratio of 1.67, which are characterized by newberyite phase formation during setting reaction, pH values close to 7, sufficient compressive strength up to 22 ± 3 MPa (for 20 mol.% of Mg), dense microstructure and adequate matrix properties of the surface. This set of features make those materials promising candidates for medical applications.
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•Self-setting magnesium-calcium phosphate cements were synthesized by one-pot processes.•Cement liquid based on NaH2PO4 warrantee the absence of ammonia release in human body.•New regularity between (Ca + Mg)/P ratio and bone cements phase formation with NaH2PO4 were established.•The optimal ratio of (Ca + Mg)/P = 1.67 resulted in neutral pH and sufficient strength.
We compared the composition and biological activity of fetal calf serum and platelet lysate from donor platelet concentrate. In platelet lysate, the concentrations of alkaline phosphatase, lactate ...dehydrogenase, creatinine, and mineral metabolism parameters were lower, while parameters of lipid and protein metabolism were higher than in fetal calf serum. The concentrations of growth factors (platelet-derived (AA, AB, BB), vascular endothelial, insulin-like, and transforming growth factor β) in platelet lysate 1.7-148.7-fold surpassed the corresponding parameters in fetal calf serum. After replacement of fetal calf serum with platelet lysate in the culture medium (0, 25, 50, 75, and 100%), the count of multipotent mesenchymal stromal cells on day 7 (in comparison with day 1) increased by 154.8, 206.6, 228.2, 367.7, and 396.5%, respectively. Thus, platelet lysate can be an adequate non-xenogenic alternative for fetal calf serum.
Sol-gel processes occurring during hydrolysis in the presence of the surfactant diethylamine were studied. It is shown that the rate of the hydrolysis of tetrabutoxytitanium with minimal water and in ...the presence of dimethylamine is determined by the competition between the process of condensation of TiO
2
nanoparticles and the process of adsorption of dimethylamine on the surface of TiO
2
particles.
Branched oligohexamethyleneguanidine hydrochloride (branched OHMG-HC) possesses high biocidal activity. This study aimed at evaluating the pharmacokinetics of branched OHMG-HC and is mandatory for ...obtaining permission to conduct clinical studies. The thermal activation method was used to obtain radioactive-labeled drugs for the investigation of substance distribution in various tissues of experimental animals (rats and rabbits). Substance administration was carried out both orally (a dose was split into two equal volumes that were applied to buccal zones of the oral cavities of the animals) and intravenously to get a clear pharmacokinetic profile. In this research, the drug was applied in the concentration of 0.77 mg/kg with the addition of 0.037 mg/kg
3
H-OHMG for rats, and 0.42 mg/kg with the addition of 0.015 mg/kg
3
H-OHMG for Chinchilla rabbits. The selected samples of blood, organs, and urine underwent alkaline mineralization. A quantitative determination of
3
H-OHMG was carried out using a liquid β-, γ-counter according to the level of scintillation in the sample. Branched OHMG-HC displayed uniform distribution within all main organs and tissues upon oral administration. The highest concentrations were found in liver and kidney tissues, whereas the lowest in blood, cardiac muscle tissue, and brain. The closeness of the f
abs
values obtained from different animals (24.5% for rats and 29.0% for rabbits) demonstrated the absence of the species specificity in response to the pharmaceutical substance. The main parameters of excretion were established, and the half-life time was estimated to be 15 h.
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