221,045 results match your criteria: "Russia; St. Petersburg State University[Affiliation]"

: Reference materials are essential for ensuring the accuracy and traceability of measurements in the quality control of medicinal products. This study explores new principles for the preparation of impure materials of active pharmaceutical substances, focusing on 1-(3-benzoylphenyl)ethanone ketoprofen impurity A () as the reference material. : The reference material was synthesised from commercially available acetanilide and benzoyl chloride.

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Human Immunodeficiency Virus (HIV) proviral reservoirs are cells that harbor integrated HIV proviral DNA within their nuclear genomes. These cells form a heterogeneous group, represented by peripheral blood mononuclear cells (PBMCs), tissue-resident lymphoid and monocytic cells, and glial cells of the central nervous system. The importance of studying the properties of proviral reservoirs is connected with the inaccessibility of integrated HIV proviral DNA for modern anti-retroviral therapies (ARTs) that block virus reproduction.

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One of the challenging problems in the research and development of vibration sensors relates to the formation of Ohmic contacts for the removal of an electrical signal. In some cases, it is proposed to use arrays of carbon nanotubes (CNTs), which can serve as highly elastic electrode materials for vibration sensors. The purpose of this work is to study the effect of a current-collecting layer of CNTs grown over silicon on the properties of a lead zirconate titanate (PZT) film, which is frequently employed in mechanical vibration sensors or energy harvesters.

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ZnO/MO (M = Fe, Co, Ni, Sn, In, Ga; [M]/([Zn] + [M]) = 15 mol%) nanofiber heterostructures were obtained by co-electrospinning and characterized by X-ray diffraction, scanning electron microscopy and X-ray fluorescence spectroscopy. The sensor properties of ZnO and ZnO/MO nanofibers were studied toward reducing gases CO (20 ppm), methanol (20 ppm), acetone (20 ppm), and oxidizing gas NO (1 ppm) in dry air. It was demonstrated that the temperature of the maximum sensor response of ZnO/MO nanofibers toward reducing gases is primarily influenced by the binding energy of chemisorbed oxygen with the surface of the modifier's oxides.

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The process of establishing relay protection and automation (RPA) settings for electric power systems (EPSs) entails complex calculations of operating modes. Traditionally, these calculations are based on symmetrical components, which require the building of equivalent circuits of various sequences. This approach can lead to errors both when identifying the operating modes and when modeling the RPA devices.

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Ultrasonographic assessment of the diameters of various veins and their indices are among the most applied diagnostic tools for evaluating fluid responsiveness in clinical practice. Despite their widespread use, there is no definitive answer on which is preferable. Our study aimed to investigate the diagnostic accuracy of different venous diameters and their indices to assess fluid responsiveness.

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To date, there have been no studies on the dynamics of areas of pain, paraesthesia and hypoesthesia after the use of various transcutaneous electrical nerve stimulation in the treatment of meralgia paresthetica. In this pilot study, we observed 68 patients with obesity-related bilateral meralgia paresthetica. Pain syndrome, paraesthesia symptoms, and hypoesthesia were evaluated using 10-point scores.

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We aim to evaluate the dynamics of glycemic status and markers of carbohydrate metabolism 12 months after coronary artery bypass grafting (CABG) and their relationship with the one-year prognosis. The analysis of outcomes of 653 patients during 1 year after coronary artery bypass grafting is presented. In those patients who visited the study center after 1 year, markers of carbohydrate metabolism (glucose, glycated hemoglobin, fructosamine, 1.

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In recent years, a number of synthetic potentiators of antibiotics have been discovered. Their action can significantly enhance the antibacterial effect and limit the spread of antibiotic resistance through inhibition of bacterial cystathionine-γ-lyase. To expand the known set of potentiators, we developed methods for the synthesis of five new representatives of 6-bromoindole derivatives-potential inhibitors of bacterial cystathionine-γ-lyase-namely potassium 3-amino-5-((6-bromoindolyl)methyl)thiophene-2-carboxylate () and its 6-bromoindazole analogs ( and ), along with two 6-broindazole analogs of the parent compound .

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The interaction of sodium phytate hydrate CHOP·xNa·yHO (phytNa) with Cu(OAc)·HO and 1,10-phenanthroline (phen) led to the anionic tetranuclear complex [Cu(HO)(phen)(phyt)]·2Na·2NH·32HO (), the structure of the latter was determined by X-ray diffraction analysis. The phytate is completely deprotonated; six phosphate fragments (with atoms P1-P6) are characterized by different spatial arrangements relative to the cyclohexane ring (1a5e conformation), which determines two different types of coordination to the complexing agents-P1 and P3, P4, and P6 have monodentate, while P2 and P5 are bidentately bound to Cu cations. The molecular structure of the anion complex is stabilized by a set of strong intramolecular hydrogen bonds involving coordinated water molecules.

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Multiresonant fluorophores are a novel class of organic luminophores with a narrow emission spectrum. They can yield organic light-emitting devices, e.g.

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In this study, the homogeneous carboxylation of potassium, sodium, and lithium phenolates in DMSO solution at 100 °C by the Kolbe-Schmitt reaction was investigated. The impact of water, phenolate concentration, and cation nature on the yield of products and reaction selectivity was demonstrated. Based on the patterns observed, it was concluded that a complex cluster mechanism governs the carboxylation reaction in the solution.

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Cancer-related deaths primarily occur due to metastasis, a process involving the migration and invasion of cancer cells. In most solid tumors, metastasis occurs through collective cell migration (CCM), guided by "cellular leaders". These leader cells generate forces through actomyosin-mediated protrusion and contractility.

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Type 1 diabetes (T1D) is related to the autoimmune destruction of β-cells, leading to their almost complete absence in patients with longstanding T1D. However, endogenous insulin secretion persists in such patients as evidenced by the measurement of plasma C-peptide. Recently, a low level of insulin has been found in non-β islet cells of patients with longstanding T1D, indicating that other islet cell types may contribute to persistent insulin secretion.

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Inorganic pyrophosphatases, or PPases, are ubiquitous enzymes whose activity is necessary for a large number of biosynthetic reactions. The catalytic function of PPases is dependent on certain conformational changes that have been previously characterized based on the comparison of the crystal structures of various complexes. The current work describes the conformational dynamics of a structural model of human mitochondrial pyrophosphatase hPPA2 using molecular dynamics simulation, all-atom principal component analysis, and coarse-grained normal mode analysis.

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Heart rate variability biofeedback (HRV BF) training aids adaptation to new climatic, geographical, and social environments. Neurophysiological changes during the HRV BF in individuals from tropical regions studying in the Arctic are not well understood. The aim of this study was to research electroencephalographic (EEG) changes during a single short-term HRV BF session in Indian and Russian students studying in the Russian Arctic.

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The behavior of low-carbon steels (LCSs), a high-strength steel and a nickel-chromium alloy in HCl solutions in the presence of N-containing organic substances has been studied. N-containing organic substances that comprise 1,2,4-triazole in their structure (substance I and substance II) provide comprehensive protection of various steel grades from corrosion and hydrogen absorption by the metal bulk in HCl solutions under both isobaric and isochoric conditions. All the compounds studied reduce, to varying degrees, the concentration of hydrogen adsorbed and absorbed by steel in HCl solutions.

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Structural Regulation and Performance Enhancement of Carbon-Based Supercapacitors: Insights into Electrode Material Engineering.

Materials (Basel)

January 2025

Department of Biological and Chemical Engineering, Jining Polytechnic, Jining 272037, China.

The development of carbon-based supercapacitors is pivotal for advancing high energy and power density applications. This review provides a comprehensive analysis of structural regulation and performance enhancement strategies in carbon-based supercapacitors, focusing on electrode material engineering. Key areas explored include pore structure optimization, heteroatom doping, intrinsic defect engineering, and surface/interface modifications.

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We proposed and investigated a refinement of technology for obtaining Mg-doped LiNbO (LN) crystals by co-doping it with B. LN:Mg (5.0 mol%) is now the most widely used material based on bulk lithium niobate.

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Deep eutectic solvents (DES) have emerged as versatile, sustainable media for the synthesis of nanomaterials due to their low toxicity, tunability, and biocompatibility. This study develops a one-step method to modify commercially available screen-printed electrodes (SPE) using laser-induced pyrolysis of DES, consisting of choline chloride and tartaric acid with dissolved nickel acetate and dispersed graphene. The electrodes were patterned using a 532 nm continuous-wave laser for the in situ formation of Ni nanoparticles decorated on graphene sheets directly on the SPE surface (Ni-G/SPE).

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High-voltage transmission lines face significant challenges due to environmental exposure, including corona discharge, ice accretion, and corrosion, which impact their durability and operational efficiency. This study investigates the performance of hydrophilic and superhydrophilic organosilane coatings applied to high-voltage wires to address these issues. Using a combination of experimental setups simulating real-world conditions, we evaluated corona discharge losses, ice adhesion, and corrosion resistance on coated and uncoated wires.

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We have proposed and developed a method for measuring the thermal conductivity of highly efficient thermal conductors. The measurement method was tested on pure metals with high thermal conductivity coefficients: aluminum (99.999 wt.

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The use of reduction leaching in the production of alumina from bauxite by the Bayer process in order to decrease the amount of waste (bauxite residue) by adding elemental iron or aluminum, as well as Fe salts and organic compounds in the stage of high-pressure leaching, requires the purchase of relatively expensive reagents in large quantities. The aim of this study was to investigate the possibility of the use of electrolytically reduced bauxite residue (BR) as a substitute for these reagents. Reduced BR was obtained from Al-goethite containing BR using a bulk cathode in alkaline suspension.

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Comparison of Pheromone Lures and Sticky Pad Color for Capturing (Lepidoptera: Gelechiidae).

Insects

January 2025

Department of Environmental Management, Institute of Environmental Engineering, RUDN University, 6 Miklukho-Maklaya St., Moscow 117198, Russia.

Tomato leaf miner (Meyrick) (Lepidoptera: Gelechiidae) has gained the status of major pest globally. Integrated pest management (IPM) consists of different control methods. This field study was conducted to evaluate the influence of different pheromone-based traps to attract the male population and the potential of sticky pads of four different colors in capturing the adults in the absence of pheromone lures.

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