3,827 results match your criteria: "St. Petersburg State University[Affiliation]"

Two new dimorphic spin-1/2 quantum magnets, α- and β-CuO(VO)Cl, were synthesized via a chemical vapor transport method that emulates mineral formation in volcanic fumaroles. α-CuO(VO)Cl () is a pure vanadate analogue of the coparsite mineral characterized by [OCu] 1 single rods, whereas β-CuO(VO)Cl () adopts a new structure type with the [OCu] 2 layered topology. The thermal expansions of both and studied by high-temperature single-crystal X-ray diffraction are reported.

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In this computational work we study complexes with two equivalent intermolecular hydrogen bonds formed between trimethyl phosphine oxide and two identical proton donors ("twin" hydrogen bonds) for a set of 70 proton donor molecules. The changes in the phosphorus chemical shift and stretching frequency of the PO group upon complexation correlate quite well with the total strength of two hydrogen bonds. A set of explicit numerical dependences is proposed for assessing interatomic distances and hydrogen bond strengths from spectral data.

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The molecular classification of endometrial cancer developed by The Cancer Genome Atlas project (TCGA, 2013) is currently actively used in gynecological oncology. According to it, endometrial carcinoma is divided into four molecular subtypes: -mutated, MMR deficient (dMMR), -aberrant and unspecified. Endometrial cancer samples belonging to the dMMR and -mutant types are characterized by specific genetic profiles reflecting the hyper- and ultramutant phenotypes of the tumor.

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Currently, the TAAR1 receptor has been identified in various cell groups in the intestinal wall. It recognizes biogenic amine compounds like phenylethylamine or tyramine, which are products of decarboxylation of phenylalanine and tyrosine by endogenous or bacterial decarboxylases. Since several gut bacteria produce these amines, TAAR1 is suggested to be involved in the interaction between the host and gut microbiota.

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Amyloid Fibrils of the s36 Protein Modulate the Morphogenesis of Eggshell.

Int J Mol Sci

November 2024

St. Petersburg Branch, Vavilov Institute of General Genetics, Russian Academy of Sciences, Universitetskaya Emb. 7/9, 199034 St. Petersburg, Russia.

is the oldest classic model object in developmental genetics. It may seem that various structures of the fruit fly at all developmental stages have been well studied and described. However, recently we have shown that some specialized structures of the eggshell contain an amyloid fibril network.

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The development of nanofibers with incorporated biologically active molecules with a targeted mode of action is a current research trend. Potential materials for the development of such systems include poly(vinyl alcohol) (PVA) and chitosan (CS) nanofibers, which are traditionally fabricated by the electrospinning of aqueous solutions of these polymers with acetic acid. To improve drug integration, ethanol was added to the binary-solvent system.

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Segmented polymers, such as polyether block amide (PEBA), exhibit unique properties due to the combination of different segments. PEBA consists of soft polyester and rigid polyamide blocks, enabling its use in various industrial applications, including membrane technologies. In this study, PEBA membranes modified with a holmium-based metal-organic framework (Ho-1,3,5-Hbtc) were developed for enhanced pervaporation separation of water/isopropanol and water/phenol mixtures.

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Transition metal dichalcogenides (TMDCs), particularly molybdenum disulfide (MoS), have gained significant attention in the field of optoelectronics and photonics due to their unique electronic and optical properties. The integration of TMDCs with plasmonic materials allows to tailor the optical response and offers significant advantages for photonic applications. This study presents a novel approach to synthesize MoS-Au nanocomposites utilizing femtosecond laser ablation in liquid to achieve tunable optical properties in the near-infrared (NIR) region.

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In this work, a set of analytical techniques, including scanning electron microscopy (SEM), Raman scattering spectroscopy, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray microanalysis (EDX) and cyclic voltammetry (CV), were used to study the impact of high-energy He ion irradiation on the structural and electrochemical characteristics of sulfur-containing multi-walled carbon nanotubes (S-MWCNTs) placed on a titanium substrate. The results indicate that the ion beam treatment of the S-MWCNT system led to an increase in the level of imperfections on the surface structures of the nanotubes due to the formation of point defects on their outer walls and the appearance of oxygen-containing functional groups, including SO groups, near these defects. At the same time, a significant increase in the sulfur concentration (by 6.

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The oxygen reduction reaction (ORR) plays a central role in energy conversion and storage technologies. A promising alternative to precious metal catalysts are non-precious metal doped carbons. Considerable efforts have been devoted to cobalt-doped carbonized polyacrylonitrile catalysts, but the optimization of their catalytic performance remains a key challenge.

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Lead Catalyzed GaAs Nanowires Grown by Molecular Beam Epitaxy.

Nanomaterials (Basel)

November 2024

Faculty of Physics, St. Petersburg State University, Universitetskaya Emb. 13B, 199034 St. Petersburg, Russia.

This study investigates the growth of gallium arsenide nanowires, using lead as a catalyst. Typically, nanowires are grown through the vapor-solid-liquid mechanism, where a key factor is the reduction in the nucleation barrier beneath the catalyst droplet. Arsenic exhibits limited solubility in conventional catalysts; however, this research explores an alternative scenario in which lead serves as a solvent for arsenic, while gallium and lead are immiscible liquids.

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Tobacco BY-2 cell culture is one of the most widely used models in plant biology. The main advantage of BY-2 suspension cultures is the synchronization of cell development and the appearance of polar elongation. In batch culture, BY-2 cells passed through the lag, proliferation, elongation, and stationary phases.

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Apert syndrome in a 3-month-old male infant.

Asian J Surg

December 2024

Department of Faculty Surgery, St. Petersburg State University, Saint Petersburg, 199106, Russia; Department of General Surgery, Shandong Linglong Yingcheng Hospital, Zhaoyuan, Yantai, China. Electronic address:

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Time-resolved fluorescence of ANS dye as a sensor of proteins LLPS.

Biochem Biophys Res Commun

December 2024

Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Ave., 194064, St. Petersburg, Russia. Electronic address:

The explosive growth in the number of works addressing the phase separation of intrinsically disordered proteins has driven both the development of new approaches and the optimization of existing methods for biomolecular condensate visualization. In this work, we studied the potential use of the fluorescent dye ANS as a sensor for liquid-liquid phase separation (LLPS), focusing on visualizing condensates formed by the stress-granules scaffold protein G3BP1. Using fluorescence lifetime imaging microscopy (FLIM), we demonstrated that ANS can accumulate in RNA-induced G3BP1 condensates in aqueous solutions, but not in G3BP1 condensates formed under macromolecular crowding conditions in highly concentrated PEG solutions.

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There is an unmet need for a biomarker of liver fat. We identified dimethylguanidino valeric acid (DMGV) as a circulating biomarker of liver fat. Here, we assess its two isoforms-symmetric (SDGV) and asymmetric (ADGV)-as biomarkers of steatosis.

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Background And Purpose: Slow-acting biogenic amines, such as dopamine, are known to modulate fast neurotransmitters e.g. glutamate.

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International literature on the history of Russian psychology is largely limited to the development of Activity theory and cultural-historical theory. This paper aims to go beyond these limits by introducing a figure little known to an international audience, Boris Parygin, who emerged in the 1960s with his "grand" project for the development of Russian social psychology, significantly different from the Soviet psychology "mainstream," stemming from Vygotsky, Luria, and Alexei Nikolaevich Leontiev. We demonstrate that Parygin's works belong to a theoretical and methodological tradition of social and humanitarian scholarship that had been developing in Russia since 1870s.

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Introduction: Carotid endarterectomy (CEA) is a surgery aimed at removing atherosclerotic plaque from the carotid artery. There are classical and eversion CEA techniques. The eversion technique is the most popular because it does not require the use of implants.

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Structures of hexamethyl-[1,1'-biphenyl]-4,4'-diammonium salts.

Acta Crystallogr B Struct Sci Cryst Eng Mater

December 2024

South Ural State University, Lenin prospekt 76, Chelyabinsk, 454080, Russian Federation.

The crystal structures of nine hexamethyl-[1,1'-biphenyl]-4,4'-diammonium (HMB) salts are described: the iodide (2), triiodide (3), succinate (4), fumarate (5), tetravanadate (6), hydroterephthalate (7) and perylenetetracarboxylate (8), as well as pentamethyl-[1,1'-biphenyl]-4,4'-diammonium iodide (1) and the metal-organic framework sodium diacetylenedisalicylate-HMB (9). HMB carbonate (10) has been synthesized as an important intermediate for a promising anti-metal-organic framework (`anti-MOF'). All the described compounds are characterized by high solubility in water.

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Features of gas chromatographic analysis of thermally unstable compounds.

J Chromatogr A

November 2024

St. Petersburg State University, Institute for Chemistry, Universitetskii ave., 26, St. Petersburg 198504, Russia.

Confirming the stability of analytes during gas chromatographic (GC) analysis is an important criterion, especially for previously uncharacterized compounds. However, the variations of absolute peak areas at different injector temperatures usually do not allow us to reveal the thermal instability of analytes during GC analysis. Such variations may be caused by peak area known discrimination typical for using capillary columns, especially at low split injection.

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Nanothermometry in transmission electron microscopy (TEM) is useful for comprehending the functioning mechanisms of the heterogeneous matter through real-time observations. Herein, we introduce a Boltzmann-distribution-driven cathodoluminescence (CL) nanothermometry for local temperature probing in TEM. The population distribution across the close-lying Stark sublevels of dysprosium ions in an yttrium vanadate matrix follows the Boltzmann distribution, enabling the use of the CL-intensity ratio as a thermometry over a wide temperature range of 103-435 K with a relative sensitivity exceeding 3% K and precision of ±2%.

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Article Synopsis
  • * Diagnosing sarcoidosis is challenging due to its diverse presentations and the absence of specific biomarkers, leading to complications in understanding its course and treatment.
  • * The review emphasizes the need for new diagnostic criteria and recommends developing a reliable immunological or imaging marker to improve diagnosis and prognosis for patients with chronic sarcoidosis.
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Recent Advances in the Growth and Compositional Modelling of III-V Nanowire Heterostructures.

Nanomaterials (Basel)

November 2024

Faculty of Physics, St. Petersburg State University, Universitetskaya Emb. 13B, 199034 St. Petersburg, Russia.

Article Synopsis
  • - Nanowire heterostructures enhance the integration of III-V photonics with silicon electronics, allowing for precise bandgap engineering and improved optical properties.
  • - Recent advancements in modeling these structures focus on deterministic approaches based on classical nucleation and growth theories, helping to understand the formation mechanisms and interfacial profiles.
  • - A variety of models exist for predicting heterostructure behavior, each with unique parameters and limitations, and there is a need for further research to refine these methods and enhance their applicability to experimental data.
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