122 results match your criteria: "Universitetsky pr.[Affiliation]"

The choice of ionic-liquid-like monomers (ILM) for single-ion conducting polyelectrolytes (SICPs) is crucial for the performance of all-solid-state lithium batteries. In the current study, we propose a novel approach for development of SICPs via design and synthesis of a new ILM with long poly(ethylene oxide) spacer between methacrylic group and (trifluoromethane)sulfonylimide anion. Its homopolymer shows an ionic conductivity that is ∼5 orders of magnitude higher (9.

View Article and Find Full Text PDF

Correction: Toikka et al. Some Remarks on the Boundary of Thermodynamic Stability. 2023, , 969.

Entropy (Basel)

June 2024

Department of Chemical Thermodynamics & Kinetics, Saint Petersburg State University, Universitetsky pr. 26, Peterhof, Saint Petersburg 198504, Russia.

The authors would like to make a tiny but important correction to the published paper [...

View Article and Find Full Text PDF

In the present report, a novel dual pH-O sensor based on covalent conjugate of rhodamine 6G and cyclometalated iridium complex with poly(vinylpyrrolidone-block-vinyltetrazole) copolymer is reported. In model physiological solutions the sensor chromophores display independent phosphorescent and fluorescent lifetime responses onto variations in oxygen concentration and pH, respectively. Colocalization studies on Chinese hamster ovary cells demonstrate the preferential localization in endosomes and lysosomes.

View Article and Find Full Text PDF

Dicarboxylate metallosurfactants (AASM), synthesized by mixing N-dodecyl aminomalonate, -aspartate and -glutamate with CaCl, MnCl and CdCl, were characterized by XRD, FTIR, and NMR spectroscopy. Layered structures, formed by metallosurfactants, were evidenced from differential scanning calorimetry and thermogravimetric analyses. Solvent-spread monolayer of AASM in combination with soyphosphatidylcholine (SPC) and cholesterol (CHOL) were studied using Langmuir surface balance.

View Article and Find Full Text PDF

Self-assembly gives rise to the versatile strategies of smart material design but requires precise control on the supramolecular level. Here, inorganic-organic synthons (conjugates) are produced by covalently grafting stearic acid tails to giant polyoxometalate (POM) Keplerate-type {Mo} through an organosilicon linker (3-aminopropyltrimethoxysilane, APTMS). Using the liposome production approach, the synthons self-assemble to form hollow nanosized vesicles (100-200 nm in diameter), which can be loaded with organic dyes─eriochrome black T (ErChB) and fluorescein (FL)─where the POM layer serves as a membrane with subnanopores for cell-like communication.

View Article and Find Full Text PDF

Interactions between a zwitterionic phospholipid, 1, 2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) and four anionic phospholipids dihexadecyl phosphate (DHP), 1, 2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG), 1, 2-dipalmitoyl-sn-glycero-3-phosphate (DPP) and 1, 2-dipalmitoyl-sn-glycero-3-phospho ethanol (DPPEth) in combination with an additional amount of 30 mol% cholesterol were separately investigated at air-buffer interface through surface pressure (π) - area (A) measurements. π-A isotherm derived parameters revealed maximum negative deviation from ideality for the mixtures comprising 30 mol% anionic lipids. Besides the film functionality, structural changes of the monomolecular films at different surface pressures in the absence and presence of polyamidoamine (PAMAM, generation 4), a cationic dendrimer, were visualised through Brewster angle microscopy and fluorescence microscopic studies.

View Article and Find Full Text PDF

Dynamic Properties of Adsorption Layers of κ-Casein Fibrils.

Langmuir

October 2023

Department of Colloid Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 St. Petersburg, Russia.

The dynamic surface properties of native κ-casein solutions and aqueous dispersions of its fibrils differ significantly from the corresponding properties of the systems with globular proteins. The dependence of the dynamic surface elasticity of κ-casein solutions on surface pressure has a local maximum, indicating partial displacement of macromolecules from the proximal region of the surface layer to the distal one. This dependence becomes monotonic for fibril dispersions, similar to the results for dispersions of globular protein fibrils, but unlike the latter case, the surface elasticity close to the steady state reaches values that are approximately four times higher than the data for native protein solutions at the same concentrations.

View Article and Find Full Text PDF

Dynamic Surface Properties of α-Lactalbumin Fibril Dispersions.

Polymers (Basel)

October 2023

Institute of Chemistry, St. Petersburg State University, Universitetsky pr. 26, St. Petersburg 198504, Russia.

The dynamic surface properties of aqueous dispersions of α-lactalbumin (ALA) amyloid fibrils differ noticeably from the properties of the fibril dispersions of other globular proteins. As a result, the protocol of the application of ALA fibrils to form stable foams and emulsions has to be deviate from that of other protein fibrils. Unlike the fibrils of β-lactoglobulin and lysozyme, ALA fibrils can be easily purified from hydrolyzed peptides and native protein molecules.

View Article and Find Full Text PDF

Some Remarks on the Boundary of Thermodynamic Stability.

Entropy (Basel)

June 2023

Department of Chemical Thermodynamics & Kinetics, Saint Petersburg State University, Universitetsky pr. 26, Peterhof, Saint Petersburg 198504, Russia.

In this paper, we have considered some elements of the classical phenomenological theory of thermodynamic stability, which seem controversial and ambiguous. The main focus is on the conditions of the stability boundary; a new version of the derivation of the relations defining the specified boundary is proposed. Although the final results, in general, coincide with the classical relations, the described approach, from our point of view, provides a clearer and more accurate idea of the stability conditions and their boundaries.

View Article and Find Full Text PDF

A structured jet explains the extreme GRB 221009A.

Sci Adv

June 2023

Sternberg Astronomical Institute, Lomonosov Moscow State University, Universitetsky pr. 13, 119234 Moscow, Russia.

Long-duration gamma-ray bursts (GRBs) are powerful cosmic explosions, signaling the death of massive stars. Among them, GRB 221009A is by far the brightest burst ever observed. Because of its enormous energy ( ≈ 10 erg) and proximity ( ≈ 0.

View Article and Find Full Text PDF

The strong influence of an amphiphilic polyelectrolyte, poly(,-diallyl--hexyl--methylammonium chloride), on the surface properties of solutions of globular proteins (lysozyme, β-lactoglobulin, bovine serum albumin, and green fluorescent protein) depends on the protein structure and allows elucidation of the contribution of hydrophobic interactions in the protein-polyelectrolyte complex formation at the liquid-gas interface. At the beginning of adsorption, the surface properties are determined by the unbound amphiphilic component, but the influence of the protein-polyelectrolyte complexes of high surface activity increases at the approach to equilibrium. The kinetic dependencies of the dilational dynamic surface elasticity with one or two local maxima give a possibility to distinguish clearly between different steps of the adsorption process and to trace the formation of the distal region of the adsorption layer.

View Article and Find Full Text PDF

The development of effective anti-cancer therapeutics remains one of the current pharmaceutical challenges. The joint delivery of chemotherapeutic agents and biopharmaceuticals is a cutting-edge approach to creating therapeutic agents of enhanced efficacy. In this study, amphiphilic polypeptide delivery systems capable of loading both hydrophobic drug and small interfering RNA (siRNA) were developed.

View Article and Find Full Text PDF

Anisotropic gold nanoparticles have been recognized as promising agents for medical diagnostics and cancer therapy due to their wide functionality, photothermal effect, and ability for optical signal amplification in the near-infrared range. In this work, a simple and rapid method for the preparation of bone-shaped gold nanoparticles coated with a dye-impregnated silica shell with an aminated surface is proposed. The possibility of further functionalization the nanostructures with a delivery vector using folic acid as an example is demonstrated.

View Article and Find Full Text PDF

Two polymerizable ionic liquids (or monomeric ionic liquids, mILs) namely 1-butyl-3-methylimidazolium and choline acrylates ([C4mim]A and ChA, respectively) were synthesized using the modified Fukumoto method from corresponding chlorides. The chemical structure of the prepared mILs was confirmed with FTIR and NMR study. Investigation of the thermal properties with DSC demonstrates that both mILs have a Tg temperature of about 180 K and a melting point around 310 K.

View Article and Find Full Text PDF

The development of non-viral delivery systems for effective gene therapy is one of the current challenges in modern biomedicinal chemistry. In this paper, the synthesis of pH- and redox-responsive amphiphilic polypeptides for intracellular DNA delivery is reported and discussed. Two series of polypeptides consisting of L-lysine, L-phenylalanine, L-histidine, and L-cysteine as well as the same amino acids with L-glutamic acid were synthesized by a combination of copolymerization of N-carboxyanhydrides of α-amino acids and post-polymerization modification of the resulting copolymers.

View Article and Find Full Text PDF

Cancer is still one of the major diseases worldwide. The discovery of new drugs and the improvement of existing ones is one of the areas of priority in the fight against cancer. Dioxadet ([5-[[4,6-bis(aziridin-1-yl)-1,3,5-triazin-2-yl]amino]-2,2-dimethyl-1,3-dioxan-5-yl]methanol) represents one of the promising 1,3,5-triazine derivatives and has cytostatic activity towards ovarian cancer.

View Article and Find Full Text PDF

The 1,3-dipolar cycloaddition of 2-(2-oxoindoline-3-ylidene)acetates with functionalized aldo- and ketonitrones proceeds with good selectivity to provide new highly functionalized 5-spiroisoxazolidines. A characteristic feature of these reactions is reversibility that allows for the control of the diastereoselectivity of cycloaddition. The reduction of obtained adducts using zinc powder in acetic acid leads to 1,3-aminoalcohols or spirolactones.

View Article and Find Full Text PDF

Spread and adsorbed layers of protein fibrils at water -air interface.

Colloids Surf B Biointerfaces

December 2022

Department of Colloid Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 St. Petersburg, Russia.

The properties of adsorbed layers of protein fibrils differ significantly from the properties of fibril spread layers on an aqueous subphase. If the dependencies of the dynamic surface elasticity on surface pressure of Lysozyme (LYS) and β-lactoglobulin (BLG) aqueous dispersions proved to be close to the results for native protein solutions, LYS and BLG spread layers on the surface of 0.1 M NaCl solution exhibited the surface elasticity more than two times higher than the values for protein solutions with the same NaCl concentatration, presumably due to lower surface concentrations of hydrolysed peptides in the latter case.

View Article and Find Full Text PDF

Spread Layers of Lysozyme Microgel at Liquid Surface.

Polymers (Basel)

September 2022

Institute of Chemistry, St. Petersburg State University, Universitetsky pr. 26, St. Petersburg 198504, Russia.

The spread layers of lysozyme (LYS) microgel particles were studied by surface dilational rheology, infrared reflection-absorption spectra, Brewster angle microscopy, atomic force microscopy, and scanning electron microscopy. It is shown that the properties of LYS microgel layers differ significantly from those of ß-lactoglobulin (BLG) microgel layers. In the latter case, the spread protein layer is mainly a monolayer, and the interactions between particles lead to the increase in the dynamic surface elasticity by up to 140 mN/m.

View Article and Find Full Text PDF

The hydration kinetics of Portland-limestone cement pastes with organic additives in the form of acetic acid and sodium acetate were studied by using solid-state C, Al and Si NMR spectroscopy. The evolution of the relative content of various phases was monitored over the period of one month: amorphous and crystalline calcite (in C spectra), ettringite, aluminum in C-S-H gel, calcium aluminates and calcium hydroaluminates (in Al spectra), as well as alite, belite and silicon in C-S-H gel (in Si spectra). The retarding effect of the additives on cement hydration at early age was demonstrated.

View Article and Find Full Text PDF

The route for the preparation of cellulose nanofiber dispersions from bacterial cellulose using ethylene glycol- or glycerol-based deep eutectic solvents (DES) is demonstrated. Choline chloride was used as a hydrogen bond acceptor and the effect of the combined influence of DES treatment and ultrasound on the thermal and mechanical properties of bacterial cellulose nanofibers (BC-NFs) is demonstrated. It was found that the maximal Young's modulus (9.

View Article and Find Full Text PDF

In this work, a novel approach is demonstrated for 3D-printing of bacterial cellulose (BC) reinforced UV-curable ion gels using two-component solvents based on 1-butyl-3-methylimidazolium chloride or choline chloride combined with acrylic acid. Preservation of cellulose's crystalline and nanofibrous structure is demonstrated using wide-angle X-ray diffraction (WAXD) and atomic force microscopy (AFM). Rheological measurements reveal that cholinium-based systems, in comparison with imidazolium-based ones, are characterised with lower viscosity at low shear rates and improved stability against phase separation at high shear rates.

View Article and Find Full Text PDF

Peptide Inhibitors of Vascular Endothelial Growth Factor A: Current Situation and Perspectives.

Pharmaceutics

August 2021

Division of Pharmaceutical Biosciences, University of Helsinki, Viikinkaari 5 E, 00014 Helsinki, Finland.

Vascular endothelial growth factors (VEGFs) are the family of extracellular signaling proteins involved in the processes of angiogenesis. VEGFA overexpression and altered regulation of VEGFA signaling pathways lead to pathological angiogenesis, which contributes to the progression of various diseases, such as age-related macular degeneration and cancer. Monoclonal antibodies and decoy receptors have been extensively used in the anti-angiogenic therapies for the neutralization of VEGFA.

View Article and Find Full Text PDF

Unique Carbonate-Based Single Ion Conducting Block Copolymers Enabling High-Voltage, All-Solid-State Lithium Metal Batteries.

Macromolecules

July 2021

GAME Lab, Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino 10129, Italy.

Safety and high-voltage operation are key metrics for advanced, solid-state energy storage devices to power low- or zero-emission HEV or EV vehicles. In this study, we propose the modification of single-ion conducting polyelectrolytes by designing novel block copolymers, which combine one block responsible for high ionic conductivity and the second block for improved mechanical properties and outstanding electrochemical stability. To synthesize such block copolymers, the ring opening polymerization (ROP) of trimethylene carbonate (TMC) monomer by the RAFT-agent having a terminal hydroxyl group is used.

View Article and Find Full Text PDF

The design of efficient vascular endothelial growth factor (VEGF) inhibitors is a high-priority research area aimed at the treatment of pathological angiogenesis. Among other compounds, has been identified as a potent VEGF-binding peptide. In order to improve the affinity to VEGF, we built a conformational constrain in its structure.

View Article and Find Full Text PDF