Phase equilibria during crystallization of melts in the uranium oxide-iron oxide system in air

The uranium oxide-iron oxide system is investigated. It is revealed that, upon both quenching and slow cooling of samples after their melting in air, the solid phase contains five crystalline phases, such as the oxide of quadruply charged uranium UO₂, the mixed oxide UO_2.66(U₃O₈), hematite FeO_1.5(Fe₂O₃ ), magnetite Fe_1.33(Fe₃O₄), and the binary compound Fe²⁺U⁶⁺O₄.     

Entrapment of Saccharomyces cerevisiae cells in u.v. crosslinked hydroxyethylcellulose/poly(ethylene oxide) double-layered gels

Double-layered gels, consisting of hydroxyethylcellulose cryogel core and poly(ethylene oxide) hydrogel shell, were synthesized with u.v. irradiation, using the same photoinitiator, (4-benzoylbenzyl) trimethylammoniumchloride (BBTMAC) for the both layers. The gels were characterized by measuring their rheological parameters, gel fraction yield, the degree of equilibrium swelling and diffusion coefficient. The diffusion coefficients for glucose and ethanol through the hydroxyethylcellulose cryogel were 3.9 × 10^?6 cm²/s and 0.97 × 10^?5 cm²/s, respectively. The applicability of these double-layered gels as carriers for immobilization was investigated by entrapment of Saccharomyces cerevisiae cells. The immobilization efficiency and cell retention were determined in batch fermentation for ethanol production from glucose. The operational stability of the gels was evaluated in batch fermentation with three consecutive runs. The ethanol yield was in the range from 60% to 77% of the theoretical yield.     

Structural Features of Cast Refractory Alloy HP40NbTi High-Temperature Oxidation. Part I. Evolution of Microstructure and Phase Composition

Metal Science and Heat Treatment - Optical and electron microscopy, x-ray spectral microanalysis, and thermogravimetric analysis in combination with differential scanning calorimetry are used to...     

Carbon foam derived from pitches modified with mineral acids by a low pressure foaming process

Carbon foams with an anisotropic texture and high mechanical strength were produced using precursors obtained after thermo-oxidation treatment of commercial coal-tar pitch with H₂SO₄ and HNO₃. The investigations of the relation between the properties of the precursor and the structure of obtained foam indicate, that the composition and softening point of the pitch precursor significantly affect the foaming process, foam structure and foam mechanical strength. The composition and properties of the modified pitches allow foam formation at relatively low pressure and fast heating rate during the foaming process without a stabilization treatment. The foaming process of pitch-based carbon foams, pre-treatment of the precursors, and the properties of resultant foams are discussed in this paper.     

Early Lipid Raft-Related Changes: Interplay between Unilateral Denervation and Hindlimb Suspension

Muscle disuse and denervation leads to muscle atrophy, but underlying mechanisms can be different. Previously, we have found ceramide (Cer) accumulation and lipid raft disruption after acute hindlimb suspension (HS), a model of muscle disuse. Herein, using biochemical and fluorescent approaches the influence of unilateral denervation itself and in combination with short-term HS on membrane-related parameters of rat soleus muscle was studied. Denervation increased immunoexpression of sphingomyelinase and Cer in plasmalemmal regions, but decreased Cer content in the raft fraction and enhanced lipid raft integrity. Preliminary denervation suppressed (1) HS-induced Cer accumulation in plasmalemmal regions, shown for both nonraft and raft-fractions; (2) HS-mediated decrease in lipid raft integrity. Similar to denervation, inhibition of the sciatic nerve afferents with capsaicin itself increased Cer plasmalemmal immunoexpression, but attenuated the membrane-related effects of HS. Finally, both denervation and capsaicin treatment increased immunoexpression of proapoptotic protein Bax and inhibited HS-driven increase in antiapoptotic protein Bcl-2. Thus, denervation can increase lipid raft formation and attenuate HS-induced alterations probably due to decrease of Cer levels in the raft fraction. The effects of denervation could be at least partially caused by the loss of afferentation. The study points to the importance of motor and afferent inputs in control of Cer distribution and thereby stability of lipid rafts in the junctional and extrajunctional membranes of the muscle.     

The “Angiogenic Switch” and Functional Resources in Cyclic Sports Athletes

Regular physical activity in cyclic sports can influence the so-called “angiogenic switch”, which is considered as an imbalance between proangiogenic and anti-angiogenic molecules. Disruption of the synthesis of angiogenic molecules can be caused by local changes in tissues under the influence of excessive physical exertion and its consequences, such as chronic oxidative stress and associated hypoxia, metabolic acidosis, sports injuries, etc. A review of publications on signaling pathways that activate and inhibit angiogenesis in skeletal muscles, myocardium, lung, and nervous tissue under the influence of intense physical activity in cyclic sports. Materials: We searched PubMed, SCOPUS, Web of Science, Google Scholar, Clinical keys, and e-LIBRARY databases for full-text articles published from 2000 to 2020, using keywords and their combinations. Results: An important aspect of adaptation to training loads in cyclic sports is an increase in the number of capillaries in muscle fibers, which improves the metabolism of skeletal muscles and myocardium, as well as nervous and lung tissue. Recent studies have shown that myocardial endothelial cells not only respond to hemodynamic forces and paracrine signals from neighboring cells, but also take an active part in heart remodeling processes, stimulating the growth and contractility of cardiomyocytes or the production of extracellular matrix proteins in myofibroblasts. As myocardial vascularization plays a central role in the transition from adaptive heart hypertrophy to heart failure, further study of the signaling mechanisms involved in the regulation of angiogenesis in the myocardium is important in sports practice. The study of the “angiogenic switch” problem in the cerebrovascular and cardiovascular systems allows us to claim that the formation of new vessels is mediated by a complex interaction of all growth factors. Although the lungs are one of the limiting systems of the body in cyclic sports, their response to high-intensity loads and other environmental stresses is often overlooked. Airway epithelial cells are the predominant source of several growth factors throughout lung organogenesis and appear to be critical for normal alveolarization, rapid alveolar proliferation, and normal vascular development. There are many controversial questions about the role of growth factors in the physiology and pathology of the lungs. The presented review has demonstrated that when doing sports, it is necessary to give a careful consideration to the possible positive and negative effects of growth factors on muscles, myocardium, lung tissue, and brain. Primarily, the “angiogenic switch” is important in aerobic sports (long distance running). Conclusions: Angiogenesis is a physiological process of the formation of new blood capillaries, which play an important role in the functioning of skeletal muscles, myocardium, lung, and nervous tissue in athletes. Violation of the “angiogenic switch” as a balance between proangiogenic and anti-angiogenic molecules can lead to a decrease in the functional resources of the nervous, musculoskeletal, cardiovascular, and respiratory systems in athletes and, as a consequence, to a decrease in sports performance.     

Increasing the corrosion resistance of equipment due to the use of film-forming amines

Results of a study of tube specimens cut from hot-water boilers show that film-forming octadecyl amine (ODA) used in the process of preservation removes deposition from the surface of the metal. An ODA film is preserved on the surface after repeated washing of the latter with hot water. The concentration of chlorides at the surface of the metal after treatment with ODA is lower than before the treatment. __________ Translated from élektricheskie Stantsii, No. 11, November 2005, pp. 15–18.