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The construction and operation of nuclear power plants are characterized by significant capital costs associated with ensuring compliance with stringent nuclear safety requirements. To ensure a low estimated cost of electricity generated at nuclear power plants, it is especially important to increase their efficiency, which depends on the thermal efficiency of the turbine unit. Based on the criterion of economic efficiency, directions for increasing the thermal efficiency of nuclear power plants with pressurized water reactors (PWR) have been studied: increasing the fresh steam pressure, reducing the steam pressure in the condenser, optimizing the structure and parameters of the second circuit, and improving the efficiency of the turbine flow parts. Significant economic losses are caused by the use of a circulating technical water-supply system provided for at all designed nuclear power plants (according to Article 60 of the Water Code of the Russian Federation). It is noted that the ban on the use of direct-flow water supply systems contradicts the world experience of creating nuclear power plants. The difference in the efficiency of cooling systems of two types is clearly shown by the example of the design indicators of the Leningrad NPP-2 (LNPP-2) and the Tianwan NPP (power unit nos. 7, 8), which use identical reactor systems (RS) but different turbine units and technical water supply systems, which determines the difference in electrical power (up to 66 MW). Using data from the PRIS (power reactor information system) information system on power reactors around the world and the results of calculations by turbine construction companies, the level of thermal efficiency of low-speed turbines abroad, achieved through comprehensive optimization of technical solutions, was assessed. The reserves for increasing the economic efficiency of domestic nuclear power plants with PWR have been identified. It was noted that foreign companies do not stop working to improve the performance of the flow part of low-speed turbine units: models have been created with a last-stage blade length of 1905 mm. According to estimates, the total economic effect from increasing the efficiency of nuclear power plants when implementing all of the above measures, expressed through allowable additional investments, is 14 billion rubles, which is comparable to the cost of supplying all the key equipment of the power unit's turbine room. [ABSTRACT FROM AUTHOR]

Efficient operation of turbine condensers is an important prerequisite for economically efficient and reliable operation of the turbine units at thermal- and nuclear power plants. Noncondensable gases entering the condenser shell space significantly affect the heat transfer intensity and, hence, the pressure at the end of the steam expansion process in the turbine. Therefore, it is important to take measures for constantly removing these gases with the minimal energy expenditures. The article considers the operation principles and operational and design characteristics of air evacuation devices used in the condensers of thermal- and nuclear power plant turbine condensers, such as water jet and steam jet ejectors, and liquid-packed ring pumps. Comparison of these devices in terms of their energy performance criteria is carried out. Conditions for ensuring adequate energy performance of water jet ejectors are shown. Based on the results obtained from the tests of water jet ejectors and liquid-packed ring pumps, it is shown that liquid-packed ring pumps do not have any essential advantages in using them as devices for evacuating noncondensable gases from steam turbine condensers. The characteristics of steam jet ejectors used at Russian thermal and nuclear power plants are given. The notion of a steam jet ejector energy efficiency is introduced. The reserves for improving the energy performance of steam jet ejectors are shown. It can be seen from the numerical analysis results that the use of steam jet ejectors is more energy efficient for the power units of nuclear power plants constructed on the basis of the AES-2006 and VVER-TOI conceptual designs than the use of liquid-packed ring pumps. In addition, liquid-packed ring pumps are essentially more costly and complex in operation. In view of a long-standing positive experience of using water jet and steam jet ejectors at thermal and nuclear power plants and their good performance, it is recommended to consider them as air evacuation devices for advanced nuclear power plant turbine units. [ABSTRACT FROM AUTHOR]

A variety of technical solutions for the design arrangements of systems of turbine units (TU) at NPPs is the result of ongoing search for ways to increase the efficiency of electricity generation. A critical element of NPP TU systems, which has a pronounced effect on the efficiency and reliability of the power unit, is the steam separation and reheat (SRH) system. Therefore, this system should have an optimal list and structure of the employed equipment. The Russian and global experience in the design and operation of NPP TUs has demonstrated that the high-potential flow of heating steam condensate (HSC) of the secondary reheater of the SRH system can be utilized using three methods: by gravity into the last high-pressure heater in the feedwater flow, into a special condensate cooler, and by pumping into the feedwater path. These methods differ in thermal efficiency, cost, and performance indicators. The article compares the feedwater heating processes for various options of the heat recovery of the high-potential HSC flow from the steam reheaters of NPP turbine units. A feasibility study of their effectiveness has been performed, taking into account the net power of the turbine unit, the specific of the employed equipment, experience in its design and operation, and price characteristics. Recommendations are prepared on the selection of a system for heat recovery of HSC from the secondary reheater and on the type of equipment used. For operating NPPs with low-speed TUs, a conceptual proposal was developed to increase the net electric power by up to 1.6 MW by the installation of a water-jet ejector for pumping the HSC from the secondary reheater into the feedwater path. [ABSTRACT FROM AUTHOR]

Introduction: Acute kidney injury (AKI) resulting from nephrotoxic medication use is prominent in hospitalized patients and is attributable to overall increases in mortality and costs of care. Serum creatinine (SCr), the current standard for identifying drug-induced AKI (DIAKI) is often delayed in its response to kidney insult by 26-36 h.Objective: This systematic review seeks to evaluate the clinical utility of several novel kidney damage and stress biomarkers for the prediction/timely detection of DIAKI, in comparison with traditional methods.Methods: A systematic review of the CINAHL, Cochrane Library, Embase, and PubMed databases was conducted per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, for articles analyzing the use of β2-microglobulin (B2M), interleukin (IL)-18, kidney injury molecule-1 (KIM-1), liver-type fatty acid-binding protein (L-FABP), neutrophil gelatinase-associated lipocalin (NGAL), and tissue inhibitor of metalloproteinase-2 * insulin-like growth factor-binding protein 7 [TIMP-1]*[IGFBP-7], for identifying DIAKI. Primary outcomes included time to DIAKI diagnosis using traditional methods and the time to significant difference in biomarker concentrations between DIAKI and non-AKI study subjects. Secondary outcomes included biomarker concentrations at the time of significant difference between the AKI status groups.Results: Fifteen unique articles were identified from the literature search. Twelve studies consisted of strictly hospitalized patient populations and three studies included hospitalized patients and patients discharged to home treatment. No studies reported values for urine volume output. Seventy-three percent of studies reported earlier times to significant difference of novel biomarker concentrations between the AKI and non-AKI groups than diagnosis of DIAKI by SCr alone. Significant variation was observed for individual urine biomarker concentrations at time of significant difference between the AKI status groups.Conclusions: All analyzed biomarkers showed potential for use as early clinical markers of DIAKI, however further consensus on threshold urine concentrations for DIAKI is needed for meaningful implementation of these biomarkers in clinical practice. [ABSTRACT FROM AUTHOR]

Abstract  The effect of various compounds on the activity and stability of a phage-associated enzyme lysing cells of streptococci of groups A and C (PlyC) was investigated. Substantial inhibition of the enzyme activity was revealed at an increased ionic strength (in the presence of NaCl) and upon the addition of carbohydrates (mono-, di-, and polysaccharides), i.e., agents stabilizing many enzymes. It was established that the enzyme activity was substantially reduced in the presence of positively charged polyelectrolytes and surfactants, whereas incubation with micelle-forming substances and negatively charged polyelectrolytes led to PlyC activation and stabilization. It was shown that, in the micellar polyelectrolyte composition M16, the enzyme retained its activity for 2 months; while in a buffer solution under the same conditions (pH 6.3, room temperature), ture), it practically completely lost its activity in 2 days. Characteristics of the enzyme thermal inactivation were found, in particular, its half-inactivation time at various temperatures; these allowed us to estimate its behavior at any temperature and to recommend conditions for its storage and use. [ABSTRACT FROM AUTHOR]

The sulphur-containing radioprotectors mercaptoethylamine (MEA), aminoethylisothiourea (AET), 2-aminothiazoline, 4-oxo-2-aminothiazoline, and S-S-3-oxapentane-1,5-diisothiourea, and the radioprotective biogenic amines serotonin, histamine, and dopamine, caused the elevation of cAMP content and intensified the rate of cAMP-dependent protein phosphorylation in tissues of animals following intraperitoneal injection at radioprotective doses. Biogenic amines stimulated the adenylate cyclase activity in membrane preparations from liver, spleen, and small-intestine mucosa; sulphur-containing radioprotectors caused no such effects. None of the radioprotectors affected cAMP and cGMP phosphodiesterases in vitro. AET and MEA inhibited guanylate cyclase in vitro, whereas serotonin and dopamine stimulated the enzyme. A biphasic change in the level of cGMP was observed in tissues after the administration of MEA and AET (more than 2-fold fall by 1-3 min after the administration of drug and 1.4-fold rise after 15-20 min); serotonin and dopamine caused a slow rise in the cGMP level; the cAMP/cGMP ratio in liver showed biphasic changes in level during the 20 min following injection of serotonin. The data obtained support the conclusion that the action of radioprotectors on cellular metabolism in animals may be mediated by the cAMP system. The reciprocal regulation of radioresistance by cAMP and cGMP is unlikely to exist. [ABSTRACT FROM AUTHOR]

Lateral protein movement in cell membranes takes place in a medium with 'obstacles'. These obstacles are: (a) aggregates of major integral proteins immobilized by submembraneous structures and cytoskeleton, and (b) membrane lipids in the gel phase. Hormonal activation of the adenylate cyclase complex is associated with lateral mobility of the constituent proteins. Modification of the interaction of these proteins due to variation of the 'fluid' lipid fraction in reticulocyte membranes has been studied. A decrease in the percentage of 'fluid' lipids in membranes resulted in the inhibition (up to the full cessation) of the interaction of β-adrenoreceptors with regulatory N-proteins. The interaction of N-proteins with catalytic proteins stopped as well. On the other hand, an increase in the 'fluid' lipid fraction led to a more intensive interaction. These facts do not arise from the functional damage of interacting proteins. Conseqently, hormonal activation of the adenylate cyclase complex depends on the fraction of 'fluid' lipids in the membrane. The data obtained are in conformity with the percolation theory which makes it possible to characterize long-distance protein movement in a medium ('fluid' lipids) containing obstacles. Thus, interacting proteins prove to diffuse within distances greatly exceeding protein sizes. As a consequence, the intrinsic activity of a β-agonist, isoproterenol, varies from 1 to 0 depending on the 'fluid' lipid fraction. Our findings also suggest that in vitro there are no β-receptors precoupled with N-proteins in rat reticulocyte membranes in the absence of guanine nucleotides. [ABSTRACT FROM AUTHOR]

In mixed culture of Chinese hamster fibroblatst, clone 431, and transformed murine L fibroblasts, clone B-82, isoproterenol was found to protect only 431 cells against ionizing radiation. It was shown that 431 cells, in contrast to B-82 cells, possess β-adrenoreceptors, and the radioprotective effect of isoproterenol can be realized only if this agent interacts with β-adrenoreceptors coupled with the cAMP system. Since malignization often causes the disappearance of β-adrenergic and other hormone receptors, the combined culturing and irradiation of the cells studied can be regarded as a model of the growth of malignant cells (B-82) among normal tissue cells (431 cells) under conditions of radiation therapy. A possibility of selective protection against radiation damage of normal tissue cells, with retention of the former radiosensitivity of tumor cells, is discussed. [ABSTRACT FROM AUTHOR]

The use of catalytic plasma anodization to obtain oxides on the surface of SiC is an original method, hitherto unused. This method can significantly reduce the process temperature, increase the oxide growth rate, and improve the properties of the structures, giving a low density of surface states and a small fixed charge in the oxide. [ABSTRACT FROM AUTHOR]