465 results match your criteria: "Universitetskaya nab. 7-9[Affiliation]"

Comparative study of fluorescence core-shell nanotags with different morphology of gold core.

Colloids Surf B Biointerfaces

June 2023

Saint-Petersburg State University, Universitetskaya nab. 7/9, 199034 Saint Petersburg, the Russian Federation. Electronic address:

The development of compact and highly active plasmonic nanotags tuned on the first transparency window of biological tissues is under demand for cell imaging applications. The optical activity of bare plasmonic nanoparticles is determined by morphology but the more complex core-shell systems require experimental verification as a shell may change the expected trends. A comparative study of fluorescence core-shell nanotags with different morphology of gold core is presented in this work.

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Three bryozoan species Anomalotoechus sp., Pseudobatostomella sp. and Cyphotrypa sp.

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Article Synopsis
  • Single crystals of 2-methylbenzimidazolium perchlorate were synthesized for the first time using a slow evaporation method involving 2-methylbenzimidazole and perchloric acid.
  • The crystal structure was analyzed through single crystal X-ray diffraction (XRD), and further confirmed with powder XRD, while complementary techniques like polarized Raman spectroscopy and FTIR assessed molecular vibrations.
  • The study revealed an optical gap of ~3.9 eV and identified two phase transitions above room temperature, indicating changes in permittivity and conductivity similar to ionic liquids during melting.
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Dual inhibitors of protein phosphotyrosine phosphatase 1B (PTP1B)/T-cell protein phosphotyrosine phosphatase (TC-PTP) based on the 3-(hydroxymethyl)-4-oxo-1,4-dihydrocinnoline scaffold have been identified. Their dual affinity to both enzymes has been thoroughly corroborated by in silico modeling experiments. The compounds have been profiled in vivo for their effects on body weight and food intake in obese rats.

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The peculiarities of viscosity data treatment for two series of polymer systems exhibiting associative properties: brush-like amphiphilic copolymers-charged alkylated N-methyl-N-vinylacetamide and N-methyl-N-vinylamine copolymer (MVAA--MVACH) and charged chains of sodium polystyrene-4-sulfonate (PSSNa) in large-scale molecular masses (MM) and in extreme-scale of the ionic strength of solutions were considered in this study. The interest in amphiphilic macromolecular systems is explained by the fact that they are considered as micellar-forming structures in aqueous solutions, and these structures are able to carry hydrophobic biologically active compounds. In the case of appearing the hydrophobic interactions, attention was paid to discussing convenient ways to extract the correct value of intrinsic viscosity η from the combined analysis of Kraemer and Huggins plots, which were considered as twin plots.

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  • A study focused on creating disubstituted carboxonium derivatives of the -decaborate anion [2,6-BHOCCH] was conducted, proposing a method involving the reaction of [BH] with benzoic acid.
  • The synthesis occurs through a two-step process, starting with a mono-substituted product, but a quicker one-step method is also suggested.
  • The structure of the resulting tetrabutylammonium salts was confirmed using X-ray analysis, and the reaction mechanism was explored with DFT calculations, revealing the importance of intermediate anionic species and the regioselectivity for the 2,6-isomer.
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Human herpes virus 6A (HHV-6A) is able to integrate into the telomeric and subtelomeric regions of human chromosomes representing chromosomally integrated HHV-6A (ciHHV-6A). The integration starts from the right direct repeat (DR) region. It has been shown experimentally that perfect telomeric repeats (pTMR) in the DR region are required for the integration, while the absence of the imperfect telomeric repeats (impTMR) only slightly reduces the frequency of HHV-6 integration cases.

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Conformational Parameters and Hydrodynamic Behavior of Poly(2-Methyl-2-Oxazoline) in a Broad Molar Mass Range.

Polymers (Basel)

January 2023

Department of Molecular Biophysics and Polymer Physics, Saint-Petersburg State University, Universitetskaya Nab. 7/9, 199034 Saint-Petersburg, Russia.

In this work, we report our results on the hydrodynamic behavior of poly(2-methyl-2-oxazoline) (PMeOx). PMeOx is gaining significant attention for use as hydrophilic polymer in pharmaceutical carriers as an alternative for the commonly used poly(ethylene glycol) (PEG), for which antibodies are found in a significant fraction of the human population. The main focus of the current study is to determine the hydrodynamic characteristics of PMeOx under physiological conditions, which serves as basis for better understanding of the use of PMeOx in pharmaceutical applications.

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ZnTe Crystal Multimode Cryogenic Thermometry Using Raman and Luminescence Spectroscopy.

Materials (Basel)

February 2023

Center for Optical and Laser Materials Research, St. Petersburg University, Universitetskaya nab. 7-9, 199034 St. Petersburg, Russia.

In this study, ZnTe crystal was applied to provide precise thermal sensing for cryogenic temperatures. Multiple techniques, namely Raman and photoluminescence spectroscopies, were used to broaden the operating temperature range and improve the reliability of the proposed thermometers. Raman-based temperature sensing could be applied in the range of 20-100 K, while luminescence-based thermometry could be utilized in a narrower range of 20-70 K.

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The structure of testes and ovaries can be described in its simplest form by the number of follicles and ovarioles they contain. Sixty-five years after the last review of the internal reproductive systems in true bugs (Heteroptera), the data accumulated today on the number of testicular follicles and ovarioles in their gonads are summarized. In addition, data on the number and type (mesadenia/ectadenia) of accessory glands are given.

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A new series of five highly emissive binuclear heteroleptic pyridyltriazole-Cu(i)-phosphine complexes 1-5 was synthesized and examined by different experimental (IR, elemental and thermogravimetric analysis, single crystal X-ray diffraction technique, UV-vis and fluorescence spectroscopy) and quantum chemical aproaches. Complexes 1-5 exhibited excellent stimuli-responsive photoluminescent performance in the solid state at room temperature (quantum yield (QY) = 27.5-52.

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Expanding Acutuncus: Phylogenetics and morphological analyses reveal a considerably wider distribution for this tardigrade genus.

Mol Phylogenet Evol

March 2023

Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, 199034, Universitetskaya nab. 7/9, Saint Petersburg, Russia; Zoological Institute of the Russian Academy of Sciences, 199034, Universitetskaja nab. 1, Saint Petersburg, Russia. Electronic address:

Article Synopsis
  • The tardigrade genus Acutuncus was previously believed to only exist in Antarctica, but recent discoveries in the Svalbard archipelago challenge this notion.
  • New populations found in the UK and Italy, along with an Antarctic population, have expanded the climatic and geographic range of Acutuncus, leading to a revision of its classification into a new family, Acutuncidae.
  • Two distinct species morpho-groups based on egg morphology have been identified, and two new species, Acutuncus mecnuffisp. nov. and Acutuncus giovanniniaesp. nov., have been described in Europe.
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The derivatization of graphene to engineer its band structure is a subject of significant attention nowadays, extending the frames of graphene material applications in the fields of catalysis, sensing, and energy harvesting. Yet, the accurate identification of a certain group and its effect on graphene's electronic structure is an intricate question. Herein, we propose the advanced fingerprinting of the epoxide and hydroxyl groups on the graphene layers via core-level methods and reveal the modification of their valence band (VB) upon the introduction of these oxygen functionalities.

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Gut Microbiota Alterations in Trace Amine-Associated Receptor 9 (TAAR9) Knockout Rats.

Biomolecules

December 2022

Institute of Translational Biomedicine, Saint Petersburg State University, Universitetskaya nab. 7/9, 199034 Saint Petersburg, Russia.

Trace amine-associated receptors (TAAR1-TAAR9) are a family of G-protein-coupled monoaminergic receptors which might have great pharmacological potential. It has now been well established that TAAR1 plays an important role in the central nervous system. Interestingly, deletion of TAAR9 in rats leads to alterations in the periphery.

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Non-covalent interactions are one of the key topics in coordination and organometallic chemistry. Examples of such weak interactions are hydrogen, halogen, and chalcogen bonds, stacking interactions, metallophilic contacts, etc. Non-covalent interactions play an important role in materials science, catalysis, and medicinal chemistry.

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An unprecedented family of three- and five-membered substituted anionic derivatives of parent pnictogenylboranes is herein reported. Reacting various combinations of the pnictogenylboranes H E'-BH -NMe (E'=P, As) with pnictogen-based nucleophiles MER1R2 (E=P, As; R1=H, R2= Bu; R1=R2=Ph; M=Na, K) allows for the isolation of the unsymmetrical products [Na(18-crown-6)][H E'-BH -EH Bu] (3: E=E'=P; 4: E=E'=As; 5: E=As, E'=P) and [M(C)][H E'-BH -EPh ] (7: E=E'=P, M=Na, C=18-crown-6; 8: E=E'=As; M=K, C=[2.2.

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The new chytridiomycete Paradinomyces triforaminorum gen. et sp. nov. co-occurs with other parasitoids during a Kryptoperidinium foliaceum (Dinophyceae) bloom in the Baltic Sea.

Harmful Algae

December 2022

Department of Invertebrate Zoology, Biological Faculty, St Petersburg State University, Universitetskaya nab. 7/9, St Petersburg, 199034, Russia; Zoological Institute of Russian Academy of Sciences, Universitetskaya nab. 1, St Petersburg, 199034, Russia; North-Western State Medical University named after I.I. Mechnikov, Kirochnaya st. 41, St Petersburg, 191015, Russia.

A new chytrid genus and species was isolated and cultured from samples obtained in the Baltic Sea during a dinoflagellate bloom event. This species is characterized by having a spherical sporangium without papillae and zoospores of 2-3 µm in diameter that are released through 3 discharge pores. Molecular phylogeny based on ribosomal operon showed its sister position to the Dinomyces cluster in Rhizophydiales.

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Stenamoeba aeronauta n. sp., a new case of sibling species in the order Thecamoebida (Amoebozoa, Discosea).

Eur J Protistol

October 2022

Department of Invertebrate Zoology, Faculty of Biology, St. Petersburg State University, Universitetskaya nab. 7/9, 199034 St. Petersburg, Russia.

A new speciesStenamoeba aeronautan. sp.was isolated from a culture of large thecamoebids during laboratory studies.

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In the last decade much attention has been paid to the development of novel approaches in luminescence thermometry, which could allow contactless and noninvasive temperature sensing when traditional thermometers are useless. Typically, an optical thermometer exploits a distinct luminescence parameter to define temperature. However, the use of multimode sensors can significantly broaden the working range and improve the reliability of the temperature measurements.

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Article Synopsis
  • The plant genus Corylus is economically significant, particularly for its nuts, but is threatened by pathogens and pests, including a newly identified mite species, Rhyncaphytoptus corylivagrans n. sp.
  • This research includes the first record of Coptophylla lamimani and expands the known eriophyoid mite complex from Corylus to 15 species across three families.
  • Molecular phylogenetic analysis suggests a close relationship between R. corylivagrans n. sp. and other species, contributing valuable insights into the biodiversity of harmful mites associated with hazelnuts, with implications for future studies of the Diptilomiopidae family.
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Glow discharge (GD) source gained an increased level of attention in relation to the analysis of volatile organic compounds (VOCs) since past work showed that this soft ionization method allowed direct analysis of VOCs with minimal fragmentation, however, the issue of fragmentation was not previously studied in detail. The aim of the present work was to investigate the effect of discharge conditions on VOC fragmentation in the system consisting of the cell with pulsed glow discharge and a time-of-flight mass spectrometer. Ionization of VOCs of different classes (hydrocarbons, alcohols, esters, and carboxylic acids) was investigated.

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Single doped CaWO:Erphosphors were synthesized and studied for application of optical thermal sensing within a wide range of 98-773 K. Ratiometric strategy utilizing two luminescence intensity ratios, one between host and Erband (LIR) and second between different Ertransitions (LIR), results in self-referencing temperature readouts. The presence of two temperature-dependent parameters could improve thermometric characteristics and broaden the working temperature range compared to a usual single-parameter thermometer.

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The co-crystallization of the lead(II) complex [Pb(SCNEt)] with tetraiodoethylene (CI) gave the co-crystal, [Pb(SCNEt)]∙½CI, whose X-ray structure exhibits only a small change of the crystal parameters than those in the parent [Pb(SCNEt)]. The supramolecular organization of the co-crystal is largely determined by an interplay between Pb⋯S tetrel bonding (TeB) and I⋯S halogen bonding (HaB) with comparable contributions from these non-covalent contacts; the TeBs observed in the parent complex, [Pb(SCNEt)], remain unchanged in the co-crystal. An analysis of the theoretical calculation data, performed for the crystal and cluster models of [Pb(SCNEt)]∙½CI, revealed the non-covalent nature of the Pb⋯S TeB (-5.

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The binding model of adenosine-specific DNA aptamer: Umbrella sampling study.

J Mol Graph Model

January 2023

Sevastopol State University, Universitetskaya 33, 299053, Sevastopol, Russia; Saint Petersburg State University, Universitetskaya Nab. 7/9, 199034, Saint Petersburg, Russia.

We report a novel model of the selective binding mechanism of adenosine-specific DNA aptamer. Our theoretical investigations of AMP (Adenosine monophosphate) dissociation from aptamer-AMP complexes reveals new details of aptamer molecular specificity and stabilisation factors. Umbrella sampling MD calculations using parmbsc1 force field shows that the disordered structure of the internal loop of the unbound aptamer hairpin has a characteristic packing of guanines, which prevents barrier-free penetration of ligands into the site cavity.

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Cyclometalated platinum(II) complexes [Pt(ppy)Cl(CNAr)] (ppy = 2-phenylpyridinato-C,; Ar = CH-2-I , CH-4-I , CH-2-F-4-I , and CH-2,4-I ) bearing ancillary isocyanide ligands were obtained by the bridge-splitting reaction between the dimer [Pt(ppy)(μ-Cl)] and 2 equiv any one of the corresponding CNAr. Complex was crystallized in two polymorphic forms, namely, and , exhibiting green (emission quantum yield of 0.5%) and orange (emission quantum yield of 12%) phosphorescence, respectively.

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