471 results match your criteria: "7-9 Universitetskaya Nab.[Affiliation]"

The reactions to novelty manifesting in mismatch negativity in the rat brain were studied. During dissociative anesthesia, mismatch negativity-like waves were recorded from the somatosensory cortex using an epidural 32-electrode array. Experimental animals: 7 wild-type Wistar rats and 3 transgenic rats.

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This study presents a dynamic Bayesian game model designed to improve predictions of ecological uncertainties leading to natural disasters. It incorporates historical signal data on ecological indicators. Participants, acting as decision-makers, receive signals about an unknown parameter-observations of a random variable's realization values before a specific time, offering insights into ecological uncertainties.

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The effect of amphiphilic block copolymer polyethylene glycol (PEG)-polypropylene glycol (PPG)-PEG concentration in the polyphenylsulfone (PPSU) casting solution and coagulation bath temperature (CBT) on the structure, separation, and antifouling performance of PPSU ultrafiltration membranes was studied for the first time. According to the phase diagram obtained, PPSU/PEG-PPG-PEG/N-methyl-2-pyrrolidone (NMP) systems are characterized by a narrow miscibility gap. It was found that 20 wt.

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This work presents for the first time the possibility of reducing and tuning the work function of field emission cathodes coated with metal oxides by changing the chemical composition of oxide coatings using an example of heat-treated CNT/NiO nanocomposite structures. These cathodes are formulated using carbon nanotube (CNT) arrays that are coated with ultrathin layers of nickel oxide (CNT/NiO) by atomic layer deposition (ALD). It was found that NiO at thicknesses of several nanometers grown on CNTs heat treated at a temperature of 350 °C can change its stoichiometric composition towards the formation of oxygen vacancies, since the Ni/Ni peak area ratio increases and the position of the Ni-O peak binding energies shifts as observed using X-ray photoelectron spectroscopy (XPS).

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Recently, increasing attention of researchers in the field of membrane technology has been paid to the development of membranes based on biopolymers. One of the well-proven polymers for the development of porous membranes is cellulose acetate (CA). This paper is devoted to the study of the influence of different parameters on ultrafiltration CA membrane formation and their transport properties, such as the variation in coagulation bath temperature, membrane shrinkage (post-treatment at 80 °C), introduction to casting CA solution of polymers (polyethylene glycol (PEG), polysulfone (PS), and Pluronic F127 (PL)) and carbon nanoparticles (SWCNTs, MWCNTs, GO, and C).

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Pervaporation is considered the most promising technology for dehydration of bioalcohols, attracting increasing attention as a renewable energy source. In this regard, the development of stable and effective membranes is required. In this study, highly efficient membranes for the enhanced pervaporation dehydration of ethanol were developed by modification of sodium alginate (SA) with a polyethylenimine (PEI) forming polyelectrolyte complex (PEC) and graphene oxide (GO).

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The nuclear charge radius of ^{32}Si was determined using collinear laser spectroscopy. The experimental result was confronted with ab initio nuclear lattice effective field theory, valence-space in-medium similarity renormalization group, and mean field calculations, highlighting important achievements and challenges of modern many-body methods. The charge radius of ^{32}Si completes the radii of the mirror pair ^{32}Ar-^{32}Si, whose difference was correlated to the slope L of the symmetry energy in the nuclear equation of state.

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Invited for the cover of this issue are Tatiyana Serebryanskaya, Mikhail Kinzhalov and co-workers at St. Petersburg State University, the Research Institute for Physical Chemical Problems, Belarusian State University, Togliatti State University and Blokhin National Medical Research Center of Oncology. The image depicts the shield of Pallas Athena with the structure of a palladium carbene complex that protects against triple-negative breast cancer.

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A complex study of the adhesion of multi-walled carbon nanotubes to a titanium surface, depending on the modes of irradiation with He ions of the "MWCNT/Ti" system, was conducted using atomic force microscopy and X-ray photoelectron spectroscopy. A quantitative assessment of the adhesion force at the interface, performed using atomic force microscopy, demonstrated its significant increase as a result of treatment of the "MWCNT/Ti" system with a beam of helium ions. The nature of the chemical bonding between multi-walled carbon nanotubes and the surface of the titanium substrate, which causes this increase in the adhesion of nanotubes to titanium as a result of ion irradiation, was investigated by X-ray photoelectron spectroscopy.

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Despite the rise of digitalization, the scrutiny of paper documents with stamps and signatures remains crucial, constituting 55-60 % of document examination court cases. Developing accessible and robust ink analysis techniques is an ongoing challenge for forensic scientists. To tackle issues related to the identification and classification of dye components in blue ballpoint pens, we have proposed an advanced approach that integrates high-performance thin-layer chromatography (HPTLC), digital color analysis (DCA), and hierarchical cluster analysis (HCA) for a simplified yet effective procedure.

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The nucleophilic addition of 3-(4-cyanopyridin-2-yl)-1,1-dimethylurea () to -[Pt(CNXyl)Cl] () gave a new cyclometallated compound . It was characterized by NMR spectroscopy (H, C, Pt) and high-resolution mass spectrometry, as well as crystallized to obtain two crystalline forms ( and ·2MeCN), whose structures were determined by X-ray diffraction. In the crystalline structure of , two conformers ( and ) were identified, while the structure ·2MeCN had only one conformer .

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Redox-conducting polymers based on SalEn-type complexes have attracted considerable attention due to their potential applications in electrochemical devices. However, their charge transfer mechanisms, physical and electrochemical properties remain unclear, hindering their rational design and optimization. This study aims to establish the influence of monomer geometry on the polymer's properties by investigating the properties of novel nonplanar SalEn-type complexes, poly[N,N'-bis(salicylidene)propylene-2-(hydroxy)diaminonickel(II)], and its analog with 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO)-substituted bridge (MTS).

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Silicon carbide (SiC) is a wide-band gap semiconductor that exceeds other semiconducting materials (except diamond) in electrical, mechanical, chemical, and radiation stability. In this paper, we report a novel approach to fabrication of SiC nano films on a Si substrate, which is based on the endotaxial growth of a SiC crystalline phase in a graphite-like carbon (GLC) matrix. GLC films were formed by carbonization of rigid rod polyimide (PI) Langmuir-Blodgett (LB) films on a Si substrate at 1000 °C in vacuum.

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Ligand exchange reaction (LER) between carbon nanoparticles and ferrocene (CpFe) was conducted several times, but there was no convincing evidence of half-sandwich CpFe coordination to multiwalled carbon nanotubes (MWCNT). In this study, MWCNT is modified by LER with ferrocene using AlCl/Al as a catalytic system. The modified MWCNT (Fc-MWCNT) are investigated for better understanding of the processes taking place on the surface of MWCNT using different spectroscopic and electrochemical methods.

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Metal-mediated self-assembly of isocyanides and methyl 4-aminopyrimidine-5-carboxylate leads to luminescent Pd and Pt complexes featuring C,N-cyclometalated acyclic diaminocarbene (ADC) ligands. The solid-state luminescent properties of these diaminocarbene derivatives are attributed to their triplet-state metal/metal-to-ligand charge-transfer (MMLCT) nature, which is driven by attractive intermolecular M···M interactions further reinforced by the intramolecular π-π interactions even in the structure of the Pd compound, which is the first Pd-ADC phosphor reported.

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Confinement Effects in Droplet Formation on a Solid Particle.

Langmuir

March 2024

Department of Statistical Physics, Saint Petersburg State University, Faculty of Physics, 7-9 Universitetskaya nab., St. Petersburg, 199034, Russia.

Formation of a droplet around a spherical solid particle in supersaturated vapor is considered. The number and stability of equilibrium solutions in a closed small system are studied in the canonical ensemble in comparison to an open system in the grand canonical ensemble. Depending on the system's parameters, two modes exist in the canonical ensemble: the first one with only one solution and the second one with three solutions; the presence of the third solution is due to confinement.

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The - and -isomers of 6-(3-(3,4-dichlorophenyl)-1,2,4-oxadiazol-5-yl)cyclohex-3-ene-1-carboxylic acid (- and -) were obtained by the reaction of 3,4-dichloro-'-hydroxybenzimidamide and -1,2,3,6-tetrahydrophthalic anhydride. Cocrystals of - with appropriate solvents (-‧½(1,2-DCE), -‧½(1,2-DBE), and -‧½CH) were grown from 1,2-dichloroethane (1,2-DCE), 1,2-dibromoethane (1,2-DBE), and a -hexane/CHCl mixture and then characterized by X-ray crystallography. In their structures, - is self-assembled to give a hybrid 2D supramolecular organic framework (SOF) formed by the cooperative action of O-H⋯O hydrogen bonding, Cl⋯O halogen bonding, and π⋯π stacking.

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Towards the development of a DNA automaton: modular RNA-cleaving deoxyribozyme logic gates regulated by miRNAs.

Analyst

March 2024

Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, 9 Lomonosova Str., 191002, St. Petersburg, Russian Federation.

Advancements in DNA computation have unlocked molecular-scale information processing possibilities, utilizing the intrinsic properties of DNA for complex logical operations with transformative applications in biomedicine. DNA computation shows promise in molecular diagnostics, enabling precise and sensitive detection of genetic mutations and disease biomarkers. Moreover, it holds potential for targeted gene regulation, facilitating personalized therapeutic interventions with enhanced efficacy and reduced side effects.

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Hydrolytically stable Pd and Pt complexes supported by acyclic diaminocarbene ligands represent a novel class of structural organometallic anticancer agents exhibiting nanomolar antiproliferative activity in a panel of cancer cell lines (IC 0.07-0.81 μM) and up to 300-fold selectivity for cancer cells over normal primary fibroblasts.

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We report the synthesis and characterization of a new 4-methoxyphenyl-2,2'-bipyridine-based ligand, such as 12, bearing dipicolylaminomethyl core as a receptor unit, as a probe for the fluorescence "turn-on" detection of Zn. Thus, in the presence of Zn the probe 12 exhibited a fluorescence enhancement with a Stokes shift of ~ 180 nm and photoluminescence quantum yields value of ~ 1.0.

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In situ formation of natural deep eutectic solvent on membrane after fat hydrolysis for lindane isomers determination in peanut paste.

Talanta

May 2024

Department of Analytical Chemistry, Institute of Chemistry, Saint Petersburg State University, SPbSU, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia.

Article Synopsis
  • A novel pretreatment technique using liquid-liquid microextraction was developed, leveraging a hydrophobic natural deep eutectic solvent formed on a special membrane surface.
  • The method involves breaking down fats in food samples to create fatty acids that help produce the extraction solvent and capture target analytes.
  • This approach was effectively applied to extract and analyze specific pesticides from peanut paste, achieving high recovery rates and low detection limits for the substances.
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The development of new nanocontainers for hydrophobic drugs is one of the most important tasks of drug delivery. Dendrimers with hydrophobic interiors and soluble terminal groups have already been used as drug carriers. However, the most convenient candidates for this purpose are peptide dendrimers since their interiors could be modified by hydrophobic amino acid residues with a greater affinity for the transported molecules.

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Opportunities for fundamental physics research with radioactive molecules.

Rep Prog Phys

July 2024

School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, People's Republic of China.

Molecules containing short-lived, radioactive nuclei are uniquely positioned to enable a wide range of scientific discoveries in the areas of fundamental symmetries, astrophysics, nuclear structure, and chemistry. Recent advances in the ability to create, cool, and control complex molecules down to the quantum level, along with recent and upcoming advances in radioactive species production at several facilities around the world, create a compelling opportunity to coordinate and combine these efforts to bring precision measurement and control to molecules containing extreme nuclei. In this manuscript, we review the scientific case for studying radioactive molecules, discuss recent atomic, molecular, nuclear, astrophysical, and chemical advances which provide the foundation for their study, describe the facilities where these species are and will be produced, and provide an outlook for the future of this nascent field.

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In this work, we develop a theory for predicting details of the local structure in nonuniform multicomponent fluids that may contain chainlike and associating components. This theory is an extension─to the fluid interfaces and mesoscopic structures of different geometry─of the multilayer quasichemical model originally proposed by Smirnova to describe liquid solution in the vicinity of a planar solid wall. The basis of the theory is the "cut-and-bond" approach, much in spirit of SAFT, where an infinite attraction between the separated monomeric units of a chainlike molecule mimics the chemical bonds of the chain.

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Falls refers to geriatric syndromes, which is accompanied by a significant number of adverse clinically and socially consequences. For the rational organization of medical, social, psychological and other types of assistance and rehabilitation measures, separate groups of consequences developing as a result of a fall are distinguished: physical, functional, psychological, social. Every year, every fourth elderly and older person faces a fall, while about half of the victims seek medical help.

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