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An experimental study was conducted of the boiling characteristics of water subcooled to the saturation temperature during pulsed heating on a smooth surface with a technical roughness of up to 5 μm and on a modified surface with cylindrical pins 200 μm in height and diameter, located at the nodes of a rectangular grid with a step of 400 μm, with an upward flow with a pressure of 0.29 MPa and an average flow velocity of 0.52 m/s. It was found that at an initial water temperature of 110°C for a modified surface, the rate of increase in the heater temperature is lower, and the onset time of nucleation is the same as for a smooth surface. For an initial water temperature of 80°C and an average temperature increase rate of about 5000 K/s, it was experimentally shown that the bubbles on the modified surface are larger, but their number and the share of the area occupied by them are significantly lower than on a smooth surface.

Magnetic γ-Fe 2 O 3 /CeO 2 nanoparticles were obtained by precipitation of Ce(NO 3 ) 3 with ammonia in the presence of γ-Fe 2 O 3 seeds. The formation of CeO 2 nanoparticles on the seeds was confirmed by transmission electron microscopy linked with selected area electron diffraction, energy-dispersive X-ray spectroscopy, electron energy loss spectroscopy, and dynamic light scattering. The γ-Fe 2 O 3 /CeO 2 particle surface was functionalized with PEG-neridronate to improve the colloidal stability in PBS and biocompatibility. Chemical and in vitro biological assays proved that the nanoparticles, due to the presence of cerium oxide, effectively scavenged radicals, thus decreasing oxidative stress in the model cell line. PEG functionalization of the nanoparticles diminished their in vitro aggregation and facilitated lysosomal cargo degradation in cancer cells during autophagy, which resulted in concentration-dependent cytotoxicity of the nanoparticles. Finally, the iron oxide core allowed easy magnetic separation of the particles from liquid media and may enable monitoring of nanoparticle biodistribution in organisms using magnetic resonance imaging., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Magnetic γ-Fe 2 O 3 /CeO x nanoparticles were obtained by basic coprecipitation/oxidation of iron chlorides with hydrogen peroxide, followed by precipitation of Ce(NO 3 ) 3 with ammonia. The appearance of CeO x on the magnetic particle surface was confirmed by X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and elemental analysis; a magnetometer was used to measure the magnetic properties of γ-Fe 2 O 3 /CeO x . The relatively high saturation magnetization of the particles (41.1 A·m 2 /kg) enabled magnetic separation. The surface of γ-Fe 2 O 3 /CeO x particles was functionalized with PEG-neridronate of two different molecular weights to ensure colloidal stability and biocompatibility. The ability of the particles to affect oxidative stress in hereditary hypertriglyceridemic (HHTg) rats was tested by biological assay of the liver, kidney cortex, and brain tissues. An improvement was observed in both enzymatic [superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)] and non-enzymatic (reduced (GSH) and oxidized (GSSG) glutathione) levels of antioxidant defense and lipid peroxidation parameters [4-hydroxynonenal (4-HNE) and malondialdehyde (MDA)]. The results corresponded with chemical determination of antioxidant activity based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, proving that in the animal model γ-Fe 2 O 3 /CeO x @PEG 2,000 nanoparticles effectively scavenged radicals due to the presence of cerium oxide, in turn decreasing oxidative stress. These particles may therefore have the potential to reduce disorders associated with oxidative stress and inflammation., (Copyright © 2020 Moskvin, Marková, Malínská, Miklánková, Hüttl, Oliyarnyk, Pop-Georgievski, Zhigunov, Petrovský and Horák.)

Superparamagnetic iron oxide nanoparticles (SPIOn) are widely used as a contrast agent for cell labeling. Macrophages are the first line of defense of organisms in contact with nanoparticles after their administration. In this study we investigated the effect of silica-coated nanoparticles (γ-Fe 2 O 3 -SiO 2 ) with or without modification by an ascorbic acid (γ-Fe 2 O 3 -SiO 2 -ASA), which is meant to act as an antioxidative agent on rat peritoneal macrophages. Both types of nanoparticles were phagocytosed by macrophages in large amounts as confirmed by transmission electron microscopy and Prusian blue staining, however they did not substantially affect the viability of exposed cells in monitored intervals. We further explored cytotoxic effects related to oxidative stress, which is frequently documented in cells exposed to nanoparticles. Our analysis of double strand breaks (DSBs) marker γH2AX showed an increased number of DSBs in cells treated with nanoparticles. Nanoparticle exposure further revealed only slight changes in the expression of genes involved in oxidative stress response. Lipid peroxidation, another marker of oxidative stress, was not significantly affirmed after nanoparticle exposure. Our data indicate that the effect of both types of nanoparticles on cell viability, or biomolecules such as DNA or lipids, was similar; however the presence of ascorbic acid, either bound to the nanoparticles or added to the cultivation medium, worsened the negative effect of nanoparticles in various tests performed. The attachment of ascorbic acid on the surface of nanoparticles did not have a protective effect against induced cytotoxicity, as expected.

Magnetic nanoparticles offer multiple possibilities for biomedical applications. Besides their physico-chemical properties, nanoparticle-cellular interactions are determinant for biological safety. In this work, magnetic nanoparticles were synthesized by one-shot precipitation or two-step reaction and coated with biocompatible polymers, such as poly(l-lysine) and poly(N,N-dimethylacrylamide-co-acrylic acid), and carbohydrates, like l-ascorbic acid, d-galactose, d-mannose, and sucrose. The resulting magnetic nanoparticles were characterized by dynamic light scattering, FT-Raman spectroscopy, transmission electron microscopy, SQUID magnetometry, and Mössbauer spectroscopy. Ability of the nanoparticles to be used in theranostic applications was also evaluated, showing that coating with biocompatible polymers increased the heating efficiency. Nanoparticles synthesized by one-shot precipitation were 50% larger (∼13nm) than those obtained by a two-step reaction (∼8nm). Magnetic nanoparticles at concentrations up to 500μgmL -1 were non-cytotoxic to L929 fibroblasts. Particles synthesized by one-shot precipitation had little effect on viability, cell cycle and apoptosis of the three human colon cancer cell lines used: Caco-2, HT-29, and SW-480. At the same concentration (500μgmL -1 ), magnetic particles prepared by a two-step reaction reduced colon cancer cell viability by 20%, affecting cell cycle and inducing cell apoptosis. Uptake of surface-coated magnetic nanoparticles by colon cancer cells was dependent on particle synthesis, surface coating and incubation time., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Examined were 74 patients ranging in age from 6 to 48 years with dysplastic scoliosis. Disorders in the system of hemostasis were revealed in 67 patients. Including the 25 operated ones. The operative blood loss of more than 20 % of the circulating blood volume was noted 2 times more often in patients with the disorders in the system of hemostasis, mainly with the VIII factor deficiency. Intravenous administration of a cryoprecipitate contributed to restoration of the normal VIII factor level and more than 2-fold decrease in operative blood loss.

Interaction of saturated and unsaturated derivatives of spin-labelled fatty acids (2,2,6,6-tetramethyl-4-palmitoylpiperidil-l-oxyl (I) and synthetized by us 2,2,6,6-tetramethyl-4-oleoylpiperidil-1-oxyl (II) with sarcoplasmic reticulum membranes, retina rod outer segments and erythorocyte ghosts was studied. ESR spectra of the probe I are practically unresolved singlets, whereas ESR spectra of the probe II appear as more of less resolved triplet signals. The difference in ESR spectra of the probes I and II is the result of distribution of the probe I in pure lipid regions of membranes, the probe II being located both in lipid bilayer and hydrophobic areas of proteins.