123 results on '"Vladimir Agabekov"'
Search Results
2. Broad-Band Polarizing Light Beam Splitter Based on a Multilayer Thin-Film Coating
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S. N. Kurilkina, Vladimir Agabekov, A. A. Ryzhevich, Siyamak Shahab, Nikolai S. Kazak, A. I. Mit'kovets, V. N. Belyi, and A. G. Mashchenko
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Brewster's angle ,Materials science ,business.industry ,engineering.material ,Condensed Matter Physics ,Ray ,symbols.namesake ,Optics ,Optical coating ,Coating ,Splitter ,engineering ,symbols ,Light beam ,Degree of polarization ,Thin film ,business ,Spectroscopy - Abstract
A polarizing light beam splitter is created in the form of two Dove prisms of BK7 glass with a multilayer thin-fi lm coating made of two periodic substructures between them. The number of layers of Nb2O5 and SiO2 in each structure and their thicknesses are chosen to ensure that they reflect s-polarized and transmit p-polarized components of the incident light over the entire specified working spectral range of the splitter. This is achieved by partial overlap and supplementation by one another of photon band-gap structures of the corresponding structures at the Brewster angle. For a full divergence angle of the input light beam of up to 10o, the manufactured polarizing splitter provides a degree of polarization of 0.99 over the working wavelength range of 400–800 nm. Since the material for making the polarizing splitter is optical glass, the size of the splitters of this design is limited only by the working volume of the vacuum chambers used to deposit the optical coatings.
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- 2021
3. Multifunctional biocompatible films based on <scp>pectin‐Ag</scp> nanocomposites and <scp>PVA</scp> : Design, characterization and antimicrobial potential
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Aliaksandr Kraskouski, Kseniya Hileuskaya, Alena Ladutska, Volha Kabanava, Aliaksandr Liubimau, Galina Novik, Tran Thi Y. Nhi, and Vladimir Agabekov
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Polymers and Plastics ,Materials Chemistry ,General Chemistry ,Surfaces, Coatings and Films - Published
- 2022
4. Formation and tribological properties of octacosanoic acid monomolecular Langmuir–Blodgett films
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Viktoryia Akulova, Aliaksandr Salamianski, Ignat Chishankov, and Vladimir Agabekov
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chemistry.chemical_classification ,Materials science ,Silicon ,Precipitation (chemistry) ,Fatty acid ,chemistry.chemical_element ,General Chemistry ,Tribology ,Condensed Matter Physics ,Langmuir–Blodgett film ,chemistry ,Chemical engineering ,General Materials Science ,Octacosanoic acid - Abstract
Tribological properties of monomolecular Langmuir–Blodgett (LB) films of octacosanoic acid (OCA) fabricated on silicon substrates by horizontal precipitation (HP) method are studied. The wear resis...
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- 2021
5. Preparation of novel poly(vinyl alcohol)/chitosan lactate-based phase-separated composite films for UV-shielding and drug delivery applications
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Arfat Anis, Preetam Sarkar, Viktoryia Kulikouskaya, Dilshad Qureshi, Kseniya Hileuskaya, Samarendra Maji, Vladimir Agabekov, Biswaranjan Mohanty, Srusti Pattanaik, and Kunal Pal
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chemistry.chemical_classification ,Vinyl alcohol ,Materials science ,Polymers and Plastics ,Composite number ,02 engineering and technology ,General Chemistry ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Dielectric spectroscopy ,Chitosan ,Solvent ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Polymer blend ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Nuclear chemistry - Abstract
In this study, novel phase-separated composite films based on poly(vinyl alcohol) (PVA) and chitosan lactate (CL) were prepared by the solvent casting method. The influence of varying concentrations of CL (2.5–10% w/w) on the physicochemical properties of the films was assessed. Bright-field micrographs showed the formation of phase-separated polymeric matrices of different architectures in the CL concentration range of 2.5 and 7.5 wt%. At 10 wt% of CL, a homogenous matrix of polymer blend was observed. The developed films demonstrated excellent shielding properties against UV and visible radiation. FTIR studies confirmed the presence of hydrogen bonding between the parent polymers, i.e., PVA and CL, of the films. The film containing 7.5 wt% CL exhibited the highest crystalline nature with little crystal imperfections as compared to the remaining films. Impedance spectroscopy confirmed the conductive nature of the prepared films. The thermograms revealed that the addition of CL strongly influenced the hydrophilic interactions between the functional groups of the polymer components and the water molecules. PVA/CL composite films showed a higher % release of ciprofloxacin HCl (CPH) as compared to the pristine PVA film. CPH-loaded films showed excellent antimicrobial efficacy against model organisms. Therefore, the novel PVA/CL phase-separated composite films can potentially be used as matrices for UV-shielding and drug delivery applications.
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- 2021
6. Contact guidance of mesenchymal stem cells by flagellin-modified substrates: Aspects of cell-surface interaction from the point of view of liquid crystal theory
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Kseniya Hileuskaya, Balazs Kakasi, Viktoryia Kulikouskaya, Ferenc Vonderviszt, Viktoryia Nikalaichuk, Katsiaryna Dubatouka, Ihnat Chyshankou, Aliaksandr Kraskouski, Alexander Muravsky, Anatoli Murauski, Sergei Pinchuk, Irina Vasilevich, Igor Volotovski, and Vladimir Agabekov
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Colloid and Surface Chemistry - Published
- 2023
7. Synthesis and properties of hydrogel particles based on chitosan-ferulic acid conjugates
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Helen Nedved, Viktoryia Nikalaichuk, Nikolai Laman, Viktoryia Kulikouskaya, Vladimir Agabekov, Joanna Kalatskaja, A. N. Kraskouski, and Kseniya Hileuskaya
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Chemistry ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Chitosan ,Ferulic acid ,chemistry.chemical_compound ,stomatognathic system ,General Materials Science ,Phytotoxicity ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Carbodiimide ,Conjugate ,Nuclear chemistry - Abstract
Сhitosan-ferulic acid conjugates were synthesized by carbodiimide method and characterized by UV and FTIR spectroscopy. It has been determined that by varying the ratio of components during synthes...
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- 2021
8. Optoelectronic Device for Molecular Orientation of Functional Materials
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Soliman H. Al-Khowaiter, Al. A. Muravsky, Svetlana N. Kurilkina, Turki Saud Mohammed Al-Saud, V. N. Belyi, Nikolai A. Khilo, Vladimir Agabekov, and Nikolai S. Kazak
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Materials science ,business.industry ,Physics::Optics ,Collimator ,Conical surface ,Polarizer ,Condensed Matter Physics ,Collimated light ,law.invention ,Lens (optics) ,Angular aperture ,law ,Physics::Accelerator Physics ,Optoelectronics ,Optical radiation ,business ,Spectroscopy ,Beam (structure) - Abstract
A new approach to the development of an optoelectronic device for molecular orientation of functional materials is proposed. Results of the development of its main components are presented: a collimator for the light from an LED and a broad band polarizer with a large angular aperture. The problem of the collimation of a strongly diverging beam from an LED is examined. It is shown that the use of a modified conical lens offers promise for solving this problem. A broad-band polarizer with a large angular aperture, which is an important component of the optoelectronic device, is developed and fabricated on the basis of a multilayered structure.
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- 2021
9. Polyvinyl alcohol and pectin blended films: Preparation, characterization, and mesenchymal stem cells attachment
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Vladimir Agabekov, Sergei Pinchuk, V. A. Lapitskaya, Tatyana A. Kuznetsova, Kseniya Hileuskaya, A. N. Kraskouski, I. B. Vasilevich, Volha Kabanava, Viktoryia Kulikouskaya, and I. D. Volotovski
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food.ingredient ,Materials science ,Pectin ,0206 medical engineering ,Biomedical Engineering ,Biocompatible Materials ,macromolecular substances ,02 engineering and technology ,Dielectric barrier discharge ,Polyvinyl alcohol ,Biomaterials ,chemistry.chemical_compound ,food ,Cell Adhesion ,medicine ,Animals ,Rats, Wistar ,Cells, Cultured ,chemistry.chemical_classification ,integumentary system ,Metals and Alloys ,food and beverages ,Mesenchymal Stem Cells ,Adhesion ,Polymer ,021001 nanoscience & nanotechnology ,020601 biomedical engineering ,chemistry ,Chemical engineering ,Polyvinyl Alcohol ,Wettability ,Ceramics and Composites ,Pectins ,Glutaraldehyde ,Wetting ,Swelling ,medicine.symptom ,0210 nano-technology - Abstract
The design of novel wound dressings for chronic wound treatment is still of great importance. One of the promising approaches is application of mesenchymal stem cells (MSCs), immobilized on a flexible polymer film, for healing. In this study, blended films based on polyvinyl alcohol (PVA) and pectin with different component ratio have been prepared by solution casting method and evaluated. Physicochemical properties of the formed PVA/pectin films, including their morphology, wettability, swelling, stability, mechanical characteristics, have been studied. We demonstrated that the surface of PVA/pectin films could be modified by ultraviolet or dielectric barrier discharge plasma exposure. After both ultraviolet and plasma treatment, the hydrophilicity of PVA/pectin films increased. It has been shown that additional crosslinking of PVA/pectin films with glutaraldehyde resulted in reinforcement of their structure. MSCs were cultured on neat and modified PVA/pectin samples to evaluate the effects of film characteristics and composition on cell behavior. It has been determined that MSCs effectively adhered to glutaraldehyde-crosslinked PVA/pectin films and formed on them the monolayer culture of fibroblast-like cells. The additional modification of PVA/pectin films with collagen resulted in enhancement of MSCs adhesion. Our results show that the obtained PVA/pectin films with adhered MSCs can be suggested for potential application as a part of novel complex wound dressings.
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- 2020
10. Preparation and Properties of Hydrogel Microparticles Based on Chitosan
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Vladimir Agabekov, A. N. Kraskouski, E. L. Nedved, J. N. Kalatskaja, V. V. Nikalaichuk, Kseniya Hileuskaya, N. A. Laman, and Viktoryia Kulikouskaya
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Chemistry ,Low molecular weight chitosan ,technology, industry, and agriculture ,macromolecular substances ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Chitosan ,chemistry.chemical_compound ,Chemical engineering ,Zeta potential ,Glutaraldehyde ,0210 nano-technology - Abstract
Positively charged (zeta potential 22-31 mV) hydrogel microparticles based on low and high molecular weight chitosan were synthesized. The effect of the crosslinking agent on their physicochemical characteristics was studied. It was established, that among obtained hydrogel particles, the ones based on low molecular weight chitosan crosslinked with citrate anions, followed by additional treatment with glutaraldehyde, are the most promising as carriers of growth regulators or plant protection products.
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- 2020
11. Stereoselectivity Inversion by Water Addition in the −SO 3 H‐catalyzed Tandem Prins‐Ritter Reaction for Synthesis of 4‐amidotetrahydropyran Derivatives
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Cristina Freire, A.V. Kravtsova, Alexander Yu. Sidorenko, Konstantin P. Volcho, Päivi Mäki-Arvela, Thomas Sandberg, Andreia F. Peixoto, Vladimir Agabekov, Nikolai Li-Zhulanov, Nariman F. Salakhutdinov, and Dmitry Yu. Murzin
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Inorganic Chemistry ,Tandem ,Computational chemistry ,Chemistry ,Organic Chemistry ,Stereoselectivity ,Physical and Theoretical Chemistry ,Inversion (discrete mathematics) ,Catalysis ,Ritter reaction - Published
- 2020
12. Clay nanotubes catalyzed solvent-free synthesis of octahydro-2H-chromenols with pharmaceutical potential from (-)-isopulegol and ketones
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Nariman F. Salakhutdinov, A.Yu. Sidorenko, Konstantin P. Volcho, Johan Wärnå, Yu. V. Gatilov, Irina V. Il'ina, D. Yu. Murzin, A.V. Kravtsova, Vladimir Agabekov, and Dina V. Korchagina
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010405 organic chemistry ,Ether ,Prins reaction ,engineering.material ,010402 general chemistry ,01 natural sciences ,Halloysite ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Hydrolysis ,chemistry ,Yield (chemistry) ,Acetone ,engineering ,Organic chemistry ,Physical and Theoretical Chemistry ,Selectivity - Abstract
Natural halloysite nanotubes (HNT) pretreated with hydrochloric acid were applied for the first time for selective synthesis of octahydro-2H-chromenols (as 4R- and 4S-diastereomers) using terpenoid (-)-isopulegol and ketones as reactants. The main attention was paid to the reaction with acetone, because the resulting 4R-isomer displays antiviral activity. While the drawback of the isopulegol Prins reaction with ketones is a low yield of chromenols, considerably higher values could be achieved using a halloysite catalyst under solvent-free conditions and low temperature (30 °C) giving up to 77% overall selectivity towards chromenols. The isolated yield of the acetone-derived 4R-isomer was 66%, significantly exceeding previous results. The proposed mechanism of isopulegol condensation with ketones is more complex than in the case of aldehydes. Formation of the target chromenols occurs through addition of water to the cyclic intermediate. In parallel interactions of this intermediate with isopulegol lead to stereoselective formation of an ester with the chromene structure, which after hydrolysis gives chromenols. Formation of the ether is opposite to the Prins reaction of aliphatic alcohols with carbonyl compounds, where non-cyclic acetals are typically formed. This clearly confirms that in the Prins reaction of isopulegol with carbonyl compounds, the cyclic intermediate plays a key role. A decrease in the halloysite hydration led to an increase in ether selectivity, while with the increase in the studied catalysts acidity, formation of dehydration by-products increased. A reaction scheme for the products formation was proposed and evaluated by kinetic modelling. A possibility of the catalyst reuse has been also shown. Halloysite nanotubes can be considered as highly selective, eco-friendly, low-cost and reusable catalysts for synthesis of heterocycles based on terpenoids and ketones.
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- 2019
13. Modification of linear polymers by electron beam dispersion under vacuum
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Aleksandr A. Rogachev, Maksim A. Yarmolenko, and Vladimir Agabekov
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chemistry.chemical_classification ,Materials science ,030206 dentistry ,02 engineering and technology ,Polymer ,Polyethylene ,engineering.material ,021001 nanoscience & nanotechnology ,Polyene ,Branching (polymer chemistry) ,03 medical and health sciences ,Polyvinyl chloride ,chemistry.chemical_compound ,0302 clinical medicine ,chemistry ,Chemical engineering ,Coating ,engineering ,Molecule ,Lamellar structure ,0210 nano-technology - Abstract
The features of the molecular structure and morphology of polyethylene (PE) and polyvinyl chloride (PVC) based coatings, deposited from the products of repeated electron beam dispersion of the original polymer, are determined. Macromolecules coatings obtained by repeated dispersing of PE, contain a high concentration of unsaturated bonds and short-chain branching. The coating is formed by highly dispersed lamellar, “spiral” formations. The effect of the electron beam on PVC initiates the processes of dehydrochlorination, the formation of a polyconjugated structure. Recycled PVC-based ratings contain mainly graphite-like structures and polyene fragments, have regular pores of 300-700 nm in size, high abrasion resistance, which determines their effective use as an antibacterial layers matrix.
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- 2019
14. Modified Polypropylene Fibrous Nonwoven Materials
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Zhanna Ignatovich, Nataliya Dudchik, Aleksey Oleynik, M.A. Yarmolenko, Aleksey Mikhalko, Vladimir Agabekov, Katerina Avdeeva, Alexander A. Rogachev, and Alena Shumskaya
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Polypropylene ,chemistry.chemical_classification ,Materials science ,Polymer ,engineering.material ,Active layer ,law.invention ,chemistry.chemical_compound ,Coating ,chemistry ,law ,engineering ,Deposition (phase transition) ,Composite material ,Dispersion (chemistry) ,Layer (electronics) ,Filtration - Abstract
Polymer nonwoven materials based on polypropylene are the basis for the creation of protective medical masks. Modification of the filter layers has been performed by electron-beam deposition from the active gas phase formed by the electron-beam dispersion of PTFE. The filtration efficiency was investigated by two indicators: the PFE with a diameter of 2.5 $\mu$m (PM2.5), BFE in accordance with GOST R 58396-2019 for three-layer combinations of nonwovens, the inner layer of which had a modified coating. An increase in the filtration efficiency for both indicators was observed for all samples, which is associated with physicochemical changes of the surface of the active layer.
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- 2021
15. Physicochemical aspects of design of ultrathin films based on chitosan, pectin, and their silver nanocomposites with antiadhesive and bactericidal potential
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Alexandr Zhura, Kseniya Hileuskaya, A. N. Kraskouski, Kunal Pal, Viktoryia Kulikouskaya, Hennadiy Skorohod, Vasili Butkevich, Tsimafei Zhdanko, Vladimir Agabekov, and Stanislau Tratsyak
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Staphylococcus aureus ,Materials science ,Silver ,Biomedical Engineering ,Metal Nanoparticles ,engineering.material ,Silver nanoparticle ,Nanocomposites ,Biomaterials ,Chitosan ,chemistry.chemical_compound ,Surface roughness ,Escherichia coli ,Nanocomposite ,Metals and Alloys ,Quartz crystal microbalance ,Anti-Bacterial Agents ,chemistry ,Chemical engineering ,Ceramics and Composites ,engineering ,Pectins ,Nanometre ,Biopolymer ,Antibacterial activity - Abstract
Implant-related infection is one of the serious problems in regenerative medicine. Promising approach to overcome the problems caused by bacterial growth on the medical implants is their modification by bioactive coatings. A versatile technique for designing multilayer films with tailored characteristics at the nanometer scale is layer-by-layer assembly. In this study, multilayer films based on biopolymers (pectin and chitosan) and their nanocomposites with silver nanoparticles have been prepared and evaluated. The buildup of multilayers was monitored using the quartz crystal microbalance with dissipation technique. The morphology of the obtained films was investigated by atomic force microscopy. We have demonstrated that pectin-Ag-containing films were characterized by the linear growth and smooth defect-free surface. When pectin-Ag was substituted for the pectin in the multilayer systems, the properties of the formed coatings were significantly changed: the film rigidity and surface roughness increased, as well as the film growth acquired the parabolic character. All prepared multilayer films have shown antibacterial activity against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. The significant decrease in the number of the adhered E. coli on the multilayer surface has been determined; moreover, many of the cells were misshapen with cytoplasm leaking. The prepared multilayer films showed a mild activity against S. aureus predominantly due to the antiadhesive effect. Our results indicate that antibacterial activity of biopolymer multilayers is determined by the film composition and physicochemical characteristics and can be associated with their antiadhesive and bactericidal behaviors.
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- 2021
16. Highly selective Prins reaction over acid-modified halloysite nanotubes for synthesis of isopulegol-derived 2H-chromene compounds
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D. Yu. Murzin, A.V. Kravtsova, A.Yu. Sidorenko, Vladimir Agabekov, Atte Aho, Johan Wärnå, Ivo Heinmaa, Konstantin P. Volcho, Hanna Pazniak, and Nariman F. Salakhutdinov
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Cyclohexane ,010405 organic chemistry ,Prins reaction ,engineering.material ,010402 general chemistry ,01 natural sciences ,Halloysite ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Montmorillonite ,chemistry ,Pyridine ,engineering ,Physical and Theoretical Chemistry ,Brønsted–Lowry acid–base theory ,Selectivity ,Nuclear chemistry - Abstract
Prins reaction of terpenoid (−)-isopulegol with thiophene-2-carbaldehyde giving in substituted octahydro-2H-chromen-4-ol (as 4R- and 4S-diastereomers) was studied for the first time over a series of halloysite nanotubes (Dragon Mine, USA), treated with 1–30% HCl. Materials have been characterized by MAS NMR, XRD, XRF, N2 adsorption, FTIR with pyridine, SEM, TEM and thermal analysis methods. The quantitative data on the effect of acid treatment conditions on the content of structural units of halloysite are presented for the first time. The effect HNT treatment conditions, reaction temperature, catalyst loading, initial concentration of substrates on overall selectivity and 4R/4S ratio was studied. The diastereomers ratio decreased from 6.5 for air-dry nanotubes to 3.6 for counterparts dried at 350 °C, which clearly indicates formation of 4R-isomer on weak Bronsted acid sites At 99% isopulegol conversion in cyclohexane over HNT treated with 5% HCl an unprecedented selectivity towards 4R alone (ca. 80%) was achieved close to the sum of both diastereomers on a commercial montmorillonite K-10. The 4R/4S ratio decreased with an increase in the concentration of acid sites. The excellent selectivity on halloysite was due to the predominance of weak acid sites. On the contrary, a low chromenols yield (ca. 30%) was observed over strong Bronsted acid (resin Amberlyst-15) related to direct formation of dehydration products from the substrates. Kinetic modelling shows a substantial difference in the order to the catalyst for the dried at 110 °C resin (1.1 ± 0.12) and air-dry halloysite (1.95 ± 0.09) for the target 4R-isomer formation, which clearly indicates the key role of water in the reaction. Based on experimental results and kinetic modelling a dual mechanism of halloysite action was proposed implying formation of an intermediate with the reagents and transfer of the surface water to the intermediate giving chromenols. Stability of the catalytic properties and reusability of HNT were demonstrated. Thus, modified halloysite nanotubes can be considered as a novel type of highly selective catalysts for the Prins reaction.
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- 2019
17. Features of the Formation of Interpolyelectrolyte Complexes Based on Chitosan and Pectin
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Vladimir Agabekov, M. E. Lazouskaya, and Viktoryia Kulikouskaya
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chemistry.chemical_classification ,Infrared spectroscopy ,02 engineering and technology ,General Chemistry ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Chitosan ,Thermogravimetry ,chemistry.chemical_compound ,chemistry ,Content (measure theory) ,Zeta potential ,Electrophoretic light scattering ,0210 nano-technology ,Macromolecule ,Nuclear chemistry - Abstract
Conditions for the preparation of stable to sedimentation aqueous dispersions of interpolyelectrolyte complexes based on chitosan (Chit) and pectin (Pect) with particle diameter 0.5-0.9 μm for Pect/Chit and 1.0-2.0 μm for Chit/Pect have been determined. The absolute value of the zeta potential of these complexes is >10 mV for Pect/Chit and Chit/Pect when the molar ratio of the ionogenic groups of the polymers $$ {n}_{\mathrm{COOH}}/{n}_{{\mathrm{NH}}_2} $$ is 0.4-4.6 for Pect/Chit and 0.02-0.63 for Chit/Pect. Optical spectroscopy and electrophoretic light scattering have been used to determine the effect of molecular mass and the content of the free ionogenic groups in the polysaccharide macromolecules as well as the order of mixing the solution on the formation and properties of these interpolyelectrolyte complexes.
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- 2019
18. Preparation of chiral isobenzofurans from 3-carene in the presence of modified clays
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D. Yu. Murzin, O. V. Ardashov, Atte Aho, A.V. Kravtsova, Vladimir Agabekov, A.Yu. Sidorenko, Irina V. Il'ina, N.S. Li-Zhulanov, Konstantin P. Volcho, and Nariman F. Salakhutdinov
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010405 organic chemistry ,Process Chemistry and Technology ,Carene ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Montmorillonite ,chemistry ,Yield (chemistry) ,Pyridine ,Organic chemistry ,Physical and Theoretical Chemistry ,Selectivity ,Brønsted–Lowry acid–base theory ,Isomerization - Abstract
Isomerization of 3-carene to the reaction mixture, containing 2-carene and its further utilization in the synthesis of chiral isobenzofurans, was investigated in the presence of acid-modified clays at 140 °C. The catalysts were characterized by XRF, FTIR with pyridine and nitrogen adsorption. Quantification of the effect of the type and concentration of acid sites in different clays comprising commercial montmorillonite and natural illite on the yield of 2-carene as well as by-products was obtained for the first time. It was established that selectivity to 2-carene decreased with an increase of the Lewis to Bronsted acid sites ratio. The largest amount of 2-carene in the mixture (15.0 wt.%) with the highest ratio of 2-carene to menthadienes (0.63) was observed at 50% 3-carene conversion over a commercial montmorillonite K-30 clay, which has a moderate (100 μmol/g) acidity. It was demonstrated for the first time that the mixture containing 2-carene can be effectively used as a starting material in the reaction with vanillin resulting in chiral isobenzofurans. The products obtained in this reaction exhibit neuroprotective activity in an animal Parkinson’s disease model. It was established that isobenzofurans yield decreased with an increase in the Lewis to Bronsted acid sites ratio. The largest yield of these products was obtained in the presence of a commercial K-10 clay (59.8%), which is higher than using 2-carene per se. Catalytic synthesis of isobenzofurans based on a readily available monoterpene 3-carene instead of expensive 2-carene was thus developed.
- Published
- 2018
19. Fabrication and Characterization of Poly (vinyl alcohol) and Chitosan Oligosaccharide-Based Blend Films
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Dilshad Qureshi, Kunal Pal, Preetam Sarkar, Arfat Anis, Kseniya Hileuskaya, Viktoryia Kulikouskaya, Ayasharani Sahoo, Vladimir Agabekov, Samarendra Maji, S. Saha Ray, and Biswaranjan Mohanty
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Vinyl alcohol ,Materials science ,Polymers and Plastics ,Science ,Composite number ,Bioengineering ,General. Including alchemy ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,Biomaterials ,chemistry.chemical_compound ,Crystallinity ,QD1-65 ,Stress relaxation ,semicrystalline ,Fourier transform infrared spectroscopy ,Thermal analysis ,QD1-999 ,QD146-197 ,Hydrogen bond ,Organic Chemistry ,poly (vinyl alcohol) ,021001 nanoscience & nanotechnology ,Evaporation (deposition) ,0104 chemical sciences ,Chemistry ,chemistry ,Chemical engineering ,drug delivery ,chitosan oligosaccharide ,blends ,films ,0210 nano-technology ,Inorganic chemistry - Abstract
In the present study, we report the development of poly (vinyl alcohol) (PVA) and chitosan oligosaccharide (COS)-based novel blend films. The concentration of COS was varied between 2.5–10.0 wt% within the films. The inclusion of COS added a brown hue to the films. FTIR spectroscopy revealed that the extent of intermolecular hydrogen bonding was most prominent in the film that contained 5.0 wt% of COS. The diffractograms showed that COS altered the degree of crystallinity of the films in a composition-dependent manner. As evident from the thermal analysis, COS content profoundly impacted the evaporation of water molecules from the composite films. Stress relaxation studies demonstrated that the blend films exhibited more mechanical stability as compared to the control film. The impedance profiles indicated the capacitive-dominant behavior of the prepared films. Ciprofloxacin HCl-loaded films showed excellent antimicrobial activity against Escherichia coli and Bacillus cereus. The prepared films were observed to be biocompatible. Hence, the prepared PVA/COS-based blend films may be explored for drug delivery applications.
- Published
- 2020
20. Fabrication and characterization of ultrathin spin-coated poly(L-lactic acid) films suitable for cell attachment and curcumin loading
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Sergei Pinchuk, Ihnat Chyshankou, I. B. Vasilevich, I. D. Volotovski, Viktoryia Kulikouskaya, and Vladimir Agabekov
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Fabrication ,Morphology (linguistics) ,Materials science ,Curcumin ,Polymers ,Polyesters ,0206 medical engineering ,Biomedical Engineering ,Bioengineering ,02 engineering and technology ,Biomaterials ,Contact angle ,chemistry.chemical_compound ,Materials Testing ,Humans ,Lactic Acid ,chemistry.chemical_classification ,Spin coating ,Wound Healing ,Tissue Engineering ,Tissue Scaffolds ,Cell Membrane ,Mesenchymal Stem Cells ,Microporous material ,Polymer ,Fibroblasts ,021001 nanoscience & nanotechnology ,020601 biomedical engineering ,Characterization (materials science) ,Chemical engineering ,chemistry ,0210 nano-technology - Abstract
In the present study, ultrathin poly(L-lactic acid) (PLLA) films were fabricated using the spin-coating technique. Physicochemical properties of the formed materials, including their morphology, thickness, transparency, and contact angle, have been studied. We determined that the morphology of PLLA films could be regulated by changing the polymer concentration and humidity. By altering the humidity, microporous and flat PLLA films can be fabricated. The obtained samples were subsequently used for culturing mesenchymal stem cells and fibroblasts. It has been determined that cells effectively adhered to prepared films and formed on them a monolayer culture with high viability. It has been shown that PLLA films are suitable for the entrapment of curcumin (up to 12.1 μm cm−2) and provide its sustained release in solutions isotonic to blood plasma. The obtained PLLA films appear to be prospective materials for potential application in regenerative medicine as part of cell-containing tissue engineered dressings for chronic wound treatment.
- Published
- 2020
21. Clays catalyzed cascade Prins and Prins-Friedel-Crafts reactions for synthesis of terpenoid-derived polycyclic compounds
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I. V. Il'ina, D. Yu. Murzin, Atte Aho, A.V. Kravtsova, Nariman F. Salakhutdinov, D. V. Korchagina, Konstantin P. Volcho, Yu.M. Kurban, A.Yu. Sidorenko, Julián E. Sánchez-Velandia, Vladimir Agabekov, and N.S. Li-Zhulanov
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Benzaldehyde ,chemistry.chemical_compound ,chemistry ,Process Chemistry and Technology ,Aromatization ,Substituent ,Organic chemistry ,Lewis acids and bases ,Selectivity ,Friedel–Crafts reaction ,Catalysis ,Tetrahydrofuran - Abstract
The Prins/Friedel-Crafts cascade reactions of the terpenoid trans-4-hydroxymethyl-2-carene (synthesized from 3-carene) with aromatic aldehydes were systematically studied for the first time on acidic mesoporous clays (halloysite, illite, montmorillonites). Both the reaction rate and selectivity to the desired polycyclic product with tetrahydrofuran moiety increased with an increase in the catalyst acidity and their drying temperature, indicating that relatively strong Bronsted and Lewis acid sites favored their formation. The best activity and selectivity (up to 97%) was demonstrated over commercial montmorillonite K-10 with acidity of ca. 100 μmol/g. In contrast, on strongest acids (resin Amberlyst-15), dehydration/aromatization of the substrate was observed. It was shown, that mesoporosity of the catalyst is one of the key factors governing catalytic behavior. The presence of at least one an electron-donor substituent at the meta-position of benzaldehyde is critical for the Prins-Friedel-Crafts reaction. Overall, available montmorillonites are an effective replacement for homogeneous catalysts for the Prins/Friedel-Crafts cascade reactions.
- Published
- 2022
22. PREPARATION AND PROPERTIES OF KANAMYCIN-CONTAINING HYDROGELS BASED ON PECTIN-Ag NANOCOMPOSITE
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A. N. Kraskouski, Alena Ivanovna Ladutska, Kseniya Hileuskaya, Galina Novik, and Vladimir Agabekov
- Subjects
Green chemistry ,Nanocomposite ,food.ingredient ,Pectin ,Chemistry ,technology, industry, and agriculture ,Kanamycin ,macromolecular substances ,02 engineering and technology ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,complex mixtures ,01 natural sciences ,Silver nanoparticle ,food ,Self-healing hydrogels ,medicine ,0210 nano-technology ,Antibacterial activity ,0105 earth and related environmental sciences ,Ionotropic effect ,medicine.drug ,Nuclear chemistry - Abstract
The hydrogels based on nanocomposite pectin-Ag exhibiting the antibacterial activity (MIСAg = 0.02–0.81 mM) were obtained by ionotropic gelation. It was shown that the synthesized hydrogels had a high capacity for kanamycin (up to 70 wt. %). The obtained hydrogels provided a prolonged release of kanamycin in 0.9 % NaCl and enhanced its antibacterial activity (MIC decreased 10–20 times) due to the synergistic effect.
- Published
- 2018
23. Synthesis of Fencholenic Aldehyde from α-pinene Epoxide on Modified Clays
- Author
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A.Yu. Sidorenko, Vladimir Agabekov, E. V. Koroleva, A.V. Kravtsova, A. V. Baranovskii, Zh. V. Ignatovich, and A. L. Ermolinskaya
- Subjects
chemistry.chemical_classification ,Pinene ,010405 organic chemistry ,Epoxide ,Plant Science ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Aldehyde ,General Biochemistry, Genetics and Molecular Biology ,0104 chemical sciences ,NMR spectra database ,chemistry.chemical_compound ,chemistry ,Organic chemistry ,Isomerization ,Two-dimensional nuclear magnetic resonance spectroscopy - Abstract
The conditions for isomerization of α-pinene epoxide (2,3-epoxypinane) on modified clays that gave comparatively high contents (33.0%) of fencholenic (iso-campholenic) aldehyde in the product mixture were determined. An effective method for isolating it was proposed. The structure of iso-campholenic aldehyde was confirmed by analyzing 2D NOESY and HMBC NMR spectra.
- Published
- 2018
24. Polydimethylsiloxane Films Modified with Chitosan/Pectin Multilayers as Scaffolds for Mesenchymal Stem Cells
- Author
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I. V. Paribok, I. D. Volotovski, Vladimir Agabekov, Sergei Pinchuk, Viktoryia Kulikouskaya, A. N. Kraskouski, K. A. Matievski, and I. B. Vasilevich
- Subjects
0301 basic medicine ,food.ingredient ,Pectin ,macromolecular substances ,02 engineering and technology ,Polysaccharide ,Applied Microbiology and Biotechnology ,Biochemistry ,Chitosan ,03 medical and health sciences ,chemistry.chemical_compound ,food ,chemistry.chemical_classification ,Polydimethylsiloxane ,Mesenchymal stem cell ,technology, industry, and agriculture ,Monolayer culture ,Adhesion ,equipment and supplies ,021001 nanoscience & nanotechnology ,carbohydrates (lipids) ,030104 developmental biology ,chemistry ,Chemical engineering ,0210 nano-technology ,Layer (electronics) - Abstract
Solid (smooth) and porous films of polydimethylsiloxane (PDMS) have been obtained; the effect of their structure on the adhesion of mesenchymal stem cells (MSCs) on their surface was found. It is shown that modification of these films with a (chitosan/pectin)4 multilayer increased the efficiency of viable cell adhesion. A (3-aminopropyl)triethoxysilane–glutaraldehyde system was used to enhance the binding of the polysaccharide layer to the hydrophobic surface of PDMS. It was found that MSCs formed a monolayer culture of the fibroblast-like cells with high viability on porous PDMS modified with (chitosan/pectin)4.
- Published
- 2018
25. Acid-modified Halloysite Nanotubes as a Stereoselective Catalyst for Synthesis of 2H -Chromene Derivatives by the Reaction of Isopulegol with Aldehydes
- Author
-
Ivo Heinmaa, Vladimir Agabekov, Dmitry Yu. Murzin, Alexander Yu. Sidorenko, A.V. Kravtsova, Nariman F. Salakhutdinov, Konstantin P. Volcho, and Atte Aho
- Subjects
010405 organic chemistry ,Chemistry ,Organic Chemistry ,engineering.material ,010402 general chemistry ,01 natural sciences ,Halloysite ,Catalysis ,0104 chemical sciences ,Inorganic Chemistry ,engineering ,Organic chemistry ,2H-chromene ,Stereoselectivity ,Physical and Theoretical Chemistry - Published
- 2018
26. Unusual alignment during wet coating of oligo(phenylene vinylene)s thin films
- Author
-
A. V. Stankevich, Anatoli Murauski, Alexander Muravsky, and Vladimir Agabekov
- Subjects
Chloroform ,Materials science ,02 engineering and technology ,General Chemistry ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Coating ,Chlorobenzene ,Phenylene ,engineering ,General Materials Science ,Thin film ,0210 nano-technology ,Anisotropy - Abstract
Were formed anisotropic thin films of oligo(p-phenylene vinylene) dye on the surface of rubbed nylon during rod-coating from chloroform and chlorobenzene solutions. The order parameter and alignmen...
- Published
- 2018
27. Hydrogel Nanoparticles of Chitosan—Folic-Acid Conjugate with Imatinib Methanesulfonate
- Author
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Zh. V. Ignatovich, M. É. Lozovskaya, Vladimir Agabekov, E. V. Koroleva, and V. I. Kulikovskaya
- Subjects
Pharmacology ,010308 nuclear & particles physics ,Mesylate ,Kinetics ,Pharmacology toxicology ,technology, industry, and agriculture ,Nanoparticle ,Imatinib Methanesulfonate ,macromolecular substances ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Chitosan ,chemistry.chemical_compound ,chemistry ,Folic acid ,0103 physical sciences ,Drug Discovery ,0210 nano-technology ,Nuclear chemistry ,Conjugate - Abstract
Hydrogel particles containing up to 49 mass% imatinib methanesulfonate (mesylate) (IM) were prepared from the chitosan—folic-acid conjugate. The release kinetics of IM from the particles in solutions simulating physiological body media were studied. It was established that the release kinetics of IM from the chitosan—folic-acid conjugate particles obeyed the Korsmeyer—Peppas model and a reciprocal power function of time. It was shown that the release rate of IM from the hydrogel particles could be controlled by varying the folic-acid content in the conjugate.
- Published
- 2018
28. Layer-by-layer buildup of polysaccharide-containing films: Physico-chemical properties and mesenchymal stem cells adhesion
- Author
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Kseniya Hileuskaya, A. N. Kraskouski, Viktoryia Kulikouskaya, I. B. Vasilevich, Vladimir Agabekov, I. D. Volotovski, Sergei Pinchuk, and Kirill A. Matievski
- Subjects
Materials science ,Layer by layer ,Metals and Alloys ,Biomedical Engineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Polyelectrolyte ,Viscoelasticity ,0104 chemical sciences ,Biomaterials ,Chitosan ,chemistry.chemical_compound ,chemistry ,Tissue engineering ,Chemical engineering ,Ceramics and Composites ,Surface roughness ,Wetting ,0210 nano-technology ,Cell adhesion - Abstract
Layer-by-Layer assembled polyelectrolyte films offer the opportunity to control cell attachment and behavior on solid surfaces. In the present study, multilayer films based on negatively charged biopolymers (pectin, dextran sulfate, carboxymethylcellulose) and positively charged polysaccharide chitosan or synthetic polyelectrolyte polyethyleneimine has been prepared and evaluated. Physico-chemical properties of the formed multilayer films, including their growth, morphology, wettability, stability, and mechanical properties, have been studied. We demonstrated that chitosan-containing films are characterized by the linear growth, the defect-free surface, and predominantly viscoelastic properties. When chitosan is substituted for the polyethyleneimine in the multilayer system, the properties of the formed films are significantly altered: the rigidity and surface roughness increases, the film growth acquires the exponential character. The multilayer films were subsequently used for culturing mesenchymal stem cells. It has been determined that stem cells effectively adhered to chitosan-containing films and formed on them the monolayer culture of fibroblast-like cells with high viability. Our results show that cell attachment is a complex process which is not only governed by the surface functionality because one of the key parameter effects on cell adhesion is the stiffness of polyelectrolyte multilayer films. We therefore propose our Layer-by-Layer films for applications in tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2093-2104, 2018.
- Published
- 2018
29. Catalytic isomerization of α-pinene oxide in the presence of acid-modified clays
- Author
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Atte Aho, T.F. Kuznetsova, Ivo Heinmaa, A.Yu. Sidorenko, D. Yu. Murzin, A.V. Kravtsova, and Vladimir Agabekov
- Subjects
chemistry.chemical_classification ,Cyclohexane ,010405 organic chemistry ,Process Chemistry and Technology ,Sorption ,engineering.material ,010402 general chemistry ,01 natural sciences ,Aldehyde ,Catalysis ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Aluminosilicate ,Illite ,engineering ,Calcination ,Physical and Theoretical Chemistry ,Isomerization ,Nuclear chemistry - Abstract
Isomerization of α-pinene oxide was studied at 20–50 °C in the presence of commercial montmorillonites K-10 and K-30, acid-treated illite clay as well as synthetic aluminosilicate AS-36 using cyclohexane as a solvent. The catalysts were characterized by XRD, XRF, FTIR, MAS NMR, thermal analysis and N2 low-temperature sorption methods The main reaction products at 99.9% conversion of the substrate are campholenic and iso-campholenic aldehydes, the largest amount of which (68.1 wt.%) is formed on illite clay treated by 10% HCl. The iso-campholenic/campholenic aldehydes ratio decreases from 0.7 to 0.25 with an increase of acidity of the catalyst from 47 to 153 μmol/g. The content of products with p-menthane structure (trans-carveol, trans-sorberol, p-cymene, pinol) reaches a maximum (33.0 wt.%) in the presence of medium-acid (104.0 μmol/g) K-10 clay. The amount of campholenic aldehyde in reaction mixture increases from 34.3 to 48.2 wt.%, and content of iso-campholenic aldehyde decreases from 33.7 to 17.7 wt.% with increasing the drying (calcination) temperature of illite clay from 50 to 600 °C respectively. The scheme for the formation of reaction products on clays was proposed.
- Published
- 2018
30. ASSOCIATES OF MAGNETITE, CERIA AND FE3O4/CEO2 NANOPARTICLE COMPOSITE WITH THE CHIMERIC AMIDES CONTAINING FRAGMENTS OF IMATINIB AND PEMETREXED
- Author
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Vladimir Agabekov, A. N. Eryomin, A. V. Abakshonok, E. V. Logvinovich, Ch. A. Novik, Zh. V. Ihnatovich, and E. V. Koroleva
- Subjects
Aqueous solution ,Chemistry ,Organic Chemistry ,Composite number ,Nanoparticle ,Analytical Chemistry ,Inorganic Chemistry ,chemistry.chemical_compound ,Pemetrexed ,Chemistry (miscellaneous) ,medicine ,Surface modification ,Nanocarriers ,Protein kinase A ,Nuclear chemistry ,Magnetite ,medicine.drug - Abstract
Associates of nanoparticles (NP) of magnetite, ceria and their composite – Fe3O4 / CeO2 – with new amides containing fragments of inhibitors оf protein kinase and histone deacetylases have been obtained. Inorganic particles were formed in the presence of amides, with the one-step preparation of nanocarrier and its functionalization. In the 40-fold dilute sol, the hydrodynamic diameter of the associates increases in the series (CeO2)C2 < (Fe3O4)C2 < (Fe3O4/CeO2)C2. In an aqueous solution of 0.05 N HCl, 155 mM NaCl, simulating gastric juice, the half-time of the agglomeration of magnetite and associate of (Fe3O4)C2 is 415 and 140 minutes, respectively.
- Published
- 2018
31. Preparation and Properties of Protamine/Pectin-Ag Biopolymer Microcapsules Containing a 2-Arylaminopyrimidine Derivative
- Author
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Zh. V. Ignatovich, M. B. Golubeva, Vladimir Agabekov, E. V. Koroleva, and K. S. Gilevskaya
- Subjects
Pharmacology ,Aqueous solution ,Protamine sulfate ,biology ,010405 organic chemistry ,Chemistry ,engineering.material ,010402 general chemistry ,01 natural sciences ,Protamine ,Polyelectrolyte ,0104 chemical sciences ,Imatinib mesylate ,Adsorption ,Ionic strength ,Drug Discovery ,medicine ,biology.protein ,engineering ,Biopolymer ,medicine.drug ,Nuclear chemistry - Abstract
A synthetic 2-arylaminopyrimidine derivative (analog of imatinib mesylate) was incorporated into multilayer polyelectrolyte microcapsules prepared by alternating adsorption of protamine sulfate and pectin-Ag nanocomposite. The encapsulation effectiveness (EE) from an aqueous solution of the compound (4 mg/mL) was ~70% and reached 28 mass%. The release kinetics from the microcapsules depended significantly on the solution pH and ionic strength. Release of the imatinib analog was prolonged most in alkaline solutions. In vitro experiments on hemoblast suspension cultures showed that microencapsulation of the 2-arylaminopyrimidine derivative changed its antitumor activity and lowered the IC50 value by 1.4 – 2.2 times.
- Published
- 2018
32. Formation and Properties of LBL Films Based on Pectin and Nanocomposite of Pectin–Ag
- Author
-
Kseniya Hileuskaya, Vladimir Agabekov, and A. N. Kraskouski
- Subjects
Materials science ,food.ingredient ,Nanocomposite ,Protamine sulfate ,Pectin ,Atomic force microscopy ,Bilayer ,Organic Chemistry ,Metals and Alloys ,02 engineering and technology ,Quartz crystal microbalance ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Silver nanoparticle ,0104 chemical sciences ,Surfaces, Coatings and Films ,food ,Chemical engineering ,Materials Chemistry ,Surface roughness ,medicine ,0210 nano-technology ,medicine.drug - Abstract
Ultrathin LbL films based on protamine sulfate and pectins, including silver nanoparticles, have been obtained. Using the methods of quartz crystal microbalance and atomic force microscopy, the characteristics of the formed films are studied. It is shown that films based on pectin–Ag nanocomposites are elastic with a surface roughness of ≤3 nm, water content of
- Published
- 2018
33. Formation and Properties of Multilayer Films Based on Polyethyleneimine and Bovine Serum Albumin
- Author
-
A. N. Kraskouski, Vladimir Agabekov, M. E. Lazouskaya, and Viktoryia Kulikouskaya
- Subjects
Morphology (linguistics) ,biology ,Kinetics ,02 engineering and technology ,Quartz crystal microbalance ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Phosphate ,01 natural sciences ,Polyelectrolyte ,0104 chemical sciences ,chemistry.chemical_compound ,Adsorption ,chemistry ,Ionic strength ,biology.protein ,Physical and Theoretical Chemistry ,Bovine serum albumin ,0210 nano-technology ,Nuclear chemistry - Abstract
(Polyethyleneimine/bovine serum albumin) n ((PEI/BSA)n) multilayer films (n = 1–10) are produced via the layer-by-later deposition of polyelectrolytes. It is shown that thickness and morphology of the formed coatings can be controlled by varying the solution’s ionic strength during alternating adsorption of the components. (PEI/BSA)10 multilayer systems that contain up to 0.6 mg of antiseptic miramistin per 1 cm2 of film were created. It is established that the kinetics of miramistin release from (PEI/BSA)10 films in phosphate buffers and physiological solutions obey the Korsmeyer–Peppas equation with a high degree of accuracy (R2 > 0.95).
- Published
- 2018
34. <scp>Chitosan‐hydroxycinnamic</scp>acid conjugates: Synthesis, photostability and phytotoxicity to seed germination of barley
- Author
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Helen Nedved, Ekaterina Rybinskaya, Joanna Kalatskaja, Viktoryia Nikalaichuk, Nikolai Laman, Kseniya Hileuskaya, A. N. Kraskouski, Kanstantsin Herasimovich, Vladimir Agabekov, and Viktoryia Kulikouskaya
- Subjects
chemistry.chemical_classification ,Polymers and Plastics ,Chemistry ,General Chemistry ,Grafting ,Hydroxycinnamic acid ,Surfaces, Coatings and Films ,Chitosan ,chemistry.chemical_compound ,Germination ,Materials Chemistry ,Phytotoxicity ,Nuclear chemistry ,Conjugate - Published
- 2021
35. Catalytic isomerization of α-pinene and 3-carene in the presence of modified layered aluminosilicates
- Author
-
D. B. Utenkova, Atte Aho, J. Ganbaatar, D. Yu. Murzin, A.Yu. Sidorenko, D. Batsuren, G. M. Sen’kov, Johan Wärnå, and Vladimir Agabekov
- Subjects
010405 organic chemistry ,Process Chemistry and Technology ,Carene ,engineering.material ,010402 general chemistry ,01 natural sciences ,Cymenes ,Medicinal chemistry ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Montmorillonite ,chemistry ,Aluminosilicate ,Illite ,engineering ,Kaolinite ,Physical and Theoretical Chemistry ,Isomerization - Abstract
The catalytic properties of acid-modified montmorillonite, kaolinite (Mongolia) and illite (Belarus) clays, as well as a commercial aluminosilicate catalyst AS-36 were studied in the liquid-phase isomerization of α-pinene and 3-carene. The largest conversion of α-pinene (100% after 6 h) was observed in the presence of illite clay treated with 10% HCl at 90 °C. The presence of only weak and medium acidic sites in the clays resulted in the formation of camphene (50.1–54.3%) as the main reaction product. Conversion of 3-carene increases with an increase of the total catalyst acidity. The reaction products were 2-carene (11.9–15.0%), mentadienes (35.5–48.5%), menthenes (7.9–17.1%) and cymenes (10,1–20.4%). The amount of mentadienes in the reaction mixture decreased while the opposite was observed for menthenes and cymenes with increase of concentration and strength of the acid sites. The kinetic model for 3-carene transformations was developed.
- Published
- 2017
36. Two new dichroic dyes: Quantum chemical modeling, synthesis, optical properties and their application in polarizing films
- Author
-
Hooriye Yahyaei, Liudmila Filippovich, Vladimir I. Potkin, Sergey K. Petkevich, Sadegh Kaviani, Hongwei Zhou, Vladimir Agabekov, Siyamak Shahab, Masoome Sheikhi, Radwan Alnajjar, and E. A. Dikusar
- Subjects
010405 organic chemistry ,Chemistry ,Organic Chemistry ,010402 general chemistry ,Dichroic glass ,01 natural sciences ,Polyvinyl alcohol ,Spectral line ,0104 chemical sciences ,Analytical Chemistry ,Inorganic Chemistry ,Solvent ,chemistry.chemical_compound ,Transmittance ,Dimethylformamide ,Physical chemistry ,Density functional theory ,Polarization (electrochemistry) ,Spectroscopy - Abstract
In the present work, the quantum chemical calculations of the molecular structures of the two newly synthesized dichroic dyes: 2-methoxy-4-((1E)-((4-(phenyldiazenyl)phenyl)imino)methyl)phenyl isonicotinate (IN-1); 2-methoxy-5-((1E)-((4-(phenyldiazenyl)phenyl)imino)methyl)phenyl isonicotinate (IN-2) have been predicted using Density Functional Theory (DFT) in solvent dimethylformamide (DMF). The geometries of the dichroic dyes were optimized using the B3LYP/6-311+G* level of the theory. In addition, the electronic spectra of these compounds in solvent DMF were carried out using the same method. After quantum-chemical calculations dichroic dyes for optoelectronic applications were synthesized. Based on polyvinyl alcohol (PVA) and the new synthesized azomethine dyes polarizing films for UV/Vis regions of the spectrum were developed. The main optical parameters of polarizing PVA-films (Transmittance and Polarization Efficiency) have been measured and discussed.
- Published
- 2021
37. Catalytic synthesis of terpenoid-derived hexahydro-2H-chromenes with analgesic activity over halloysite nanotubes
- Author
-
N.S. Li-Zhulanov, I. V. Il'ina, Nariman F. Salakhutdinov, O.V. Ardashov, Vladimir Agabekov, D. Yu. Murzin, Yu.M. Kurban, A.Yu. Sidorenko, D. V. Korchagina, Johan Wärnå, and Konstantin P. Volcho
- Subjects
inorganic chemicals ,010405 organic chemistry ,Process Chemistry and Technology ,Diol ,Prins reaction ,Decanal ,engineering.material ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,Halloysite ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Nucleophile ,engineering ,Selectivity ,Trifluoromethanesulfonate - Abstract
Condensation of α-pinene derived p-menta-1,8-diene-5,6-diol (diol) with decanal was studied for the first time over modified halloysite nanotubes (HNT). The yield of the desired hexahydro-2H-chromene-4,8-diol with analgesic activity was 76–80 % practically not depending on the catalyst type, while selectivity to 4S-isomer decreased, and to 4R-isomer increased with increasing acidity. The highest selectivity to 4S-diastereomer (48.1 %) on halloysite is a result of weak acidity of this catalyst. DFT optimization of the key intermediate structure shows that the nucleophile attack proceeds at the equatorial position with the 4S-diastereomer formation, which was preferred on halloysite. On strong Bronsted (Amberlyst-15) and Lewis (scandium triflate) acids the target product yield did not exceed 37 % because of dehydration. Halloysite nanocatalysts displayed a stable performance. In the case of diol reaction with a set of carbonyl compounds, the yields of hexahydro-2H-chromene-4,8-diols (up to 88.0%) and the ratio of its 4S/4R isomers (up to 21.0) were significantly higher than on other catalysts.
- Published
- 2021
38. Microencapsulation of Imatinib Methanesulfonate
- Author
-
E. V. Koroleva, Zh. V. Ignatovich, Vladimir Agabekov, M. B. Golubeva, and K. S. Gilevskaya
- Subjects
0301 basic medicine ,Pharmacology ,Chromatography ,Chemistry ,Pharmacology toxicology ,Imatinib ,Ag nanoparticles ,Imatinib Methanesulfonate ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Polyelectrolyte ,03 medical and health sciences ,030104 developmental biology ,Prolonged release ,Drug Discovery ,medicine ,Ic50 values ,Free drug ,0210 nano-technology ,medicine.drug - Abstract
(Protamine—pectin)4 and (protamine—pectin)8 microcapsules and those containing also Ag nanoparticles were formed using the polyelectrolyte layer-by-layer (LbL) self-assembly method. The efficiency of imatinib methanesulfonate encapsulation in the microcapsules was 85.0 ± 6.0%. Microcapsules containing up to 50 mass% imatinib methanesulfonate and providing a prolonged release profile of the encapsulated drug were prepared. Encapsulation of imatinib in microcapsules increased its cytostatic activity (IC50 values reduced by 1.2 – 3.5 times) as compared with the free drug on the Molt-4, K-562, and KG-1 cell lines.
- Published
- 2017
39. Preparation and Characterization of Microfiltration Ceramic Membranes Based on Natural Quartz Sand
- Author
-
Andrei Ivanets and Vladimir Agabekov
- Subjects
Microfiltration ,ceramic ,General. Including alchemy ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,QD1-65 ,Environmental Chemistry ,Ceramic ,Quartz ,membrane ,QD1-999 ,Chemistry ,Process Chemistry and Technology ,quartz sand ,microfiltration ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Characterization (materials science) ,Membrane ,Chemical engineering ,visual_art ,visual_art.visual_art_medium ,0210 nano-technology - Abstract
The effect of phase and chemical composition of natural quartz sand, binder and burnable additives was studied. The conditions of application of the membrane and biocide layers on the formation of porous ceramic and microfiltration membranes were investigated. It is shown that a crystalline oxide of Si(IV) is determinant for obtaining the ceramic materials. The presence of carbonates (calcite, dolomite, aragonite, etc.) and crystalline aluminosilicates (microcline, albite, phlogopit, etc.) leads to a decrease in mechanical strength of ceramics. The biocide coating designed to protect the ceramic membrane surfaces from biofouling was applied and its anti-bacterial activity was shown.
- Published
- 2017
40. Formation and tribological properties of composite Langmuir–Blodgett films of stearic acid with molybdenum disulfide and amorphous carbon
- Author
-
Vladimir Agabekov and A. E. Salamianski
- Subjects
0209 industrial biotechnology ,Silicon ,General Chemical Engineering ,Composite number ,food and beverages ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Langmuir–Blodgett film ,chemistry.chemical_compound ,020901 industrial engineering & automation ,Amorphous carbon ,Chemical engineering ,chemistry ,Monolayer ,Organic chemistry ,lipids (amino acids, peptides, and proteins) ,Stearic acid ,0210 nano-technology ,Molybdenum disulfide ,Deposition (law) - Abstract
The morphology and tribological properties of Langmuir–Blodgett mono- and bilayers of stearic acid with particles of molybdenum disulfide (MoS2) and amorphous carbon (С), prepared on silicon and steel substrates by horizontal deposition (stearic acid–MoS2 and stearic acid–С monolayers) and by the “roll” technique (stearic acid–MoS2/stearic acid–С bilayers), were studied. Incorporation of C and MoS2 particles into the structure of a stearic acid film enhances its wear resistance by a factor of 2.8 and 5.5, respectively. The presence of MoS2 and С particles and of their aggregates of size from ~220 nm to 16.3 μm in stearic acid layers was confirmed by atomic force microscopy.
- Published
- 2017
41. NMR and GC Analyses of 3-Carene Isomerization Products over Activated Glauconite
- Author
-
Vladimir Agabekov, D. B. Utenkova, A. V. Baranovskii, E. D. Skakovskii, A.Yu. Sidorenko, S. E. Bogushevich, and G. M. Sen’kov
- Subjects
010405 organic chemistry ,Chemistry ,Chemical shift ,Carene ,engineering.material ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,engineering ,Organic chemistry ,Gas chromatography ,Glauconite ,Isomerization ,Spectroscopy - Abstract
The qualitative and quantitative compositions of isomerization products of 3-carene over acid-treated glauconite were established using NMR and GC methods. Chemical shifts of 1H and 13C nuclei of identified compounds were assigned. A possible mechanism of the isomerization transformations was proposed.
- Published
- 2017
42. Fabrication and characterization of pectin-based three-dimensional porous scaffolds suitable for treatment of peritoneal adhesions
- Author
-
Kseniya Hileuskaya, A. N. Kraskouski, Stanislau Tratsyak, Vladimir Agabekov, Alexandr Zhura, and Viktoryia Kulikouskaya
- Subjects
Scaffold ,Materials science ,food.ingredient ,Biocompatibility ,Pectin ,0206 medical engineering ,Biomedical Engineering ,Tissue Adhesions ,02 engineering and technology ,Biomaterials ,Peritoneal cavity ,Freeze-drying ,food ,Spectroscopy, Fourier Transform Infrared ,medicine ,Cell Adhesion ,Animals ,Rats, Wistar ,Cell Aggregation ,Tissue Scaffolds ,Mesenchymal stem cell ,Metals and Alloys ,Mesenchymal Stem Cells ,Biodegradation ,021001 nanoscience & nanotechnology ,020601 biomedical engineering ,Characterization (materials science) ,medicine.anatomical_structure ,Cross-Linking Reagents ,Ceramics and Composites ,Pectins ,Peritoneum ,0210 nano-technology ,Porosity ,Biomedical engineering - Abstract
Formation of peritoneal adhesions is common complication after abdominal and pelvic surgery. They bear a significant health problem with an influence to quality of life and health care expenses. Promising approach for their prevention is using of biodegradable barrier films for physical separation of peritoneal surfaces. In the present study, highly porous pectin-based three-dimensional (3D) scaffolds were obtained by freeze-drying technique. Physico-chemical properties of the formed materials, including their morphology, porosity, density, and stability, have been studied. The evaluation of their biocompatibility, biodegradation, and potential antiadhesion effect was studied by in vivo experiment. To reinforce the scaffolds structure and improve their stability in physiological solutions, pectin chains were cross-linked with divalent cations. We determined optimal cross-linking conditions, which allow obtaining scaffolds with desired biodegradation rate. These cross-linked scaffolds fully dissolved within 8 days in the peritoneal cavity with low presence of complications and some antiadhesive effect. It has also been determined that mesenchymal stem cells from adipose tissue could effectively adhere to the scaffolds with preservation of their viability. Our results show that obtained materials can be suggested as mechanical scaffold for delivery of the stem cells culture to peritoneal surfaces as a part of complex antiadhesive barrier system.
- Published
- 2019
43. Solvent-free synthesis of tetrahydropyran alcohols over acid-modified clays
- Author
-
Vladimir Agabekov, Zh.V. Ihnatovich, Atte Aho, Ivo Heinmaa, T.F. Kuznetsova, A.Yu. Sidorenko, D. Yu. Murzin, and Yu.M. Kurban
- Subjects
inorganic chemicals ,010405 organic chemistry ,Process Chemistry and Technology ,Tetrahydropyran ,engineering.material ,010402 general chemistry ,01 natural sciences ,Halloysite ,Catalysis ,Isovaleraldehyde ,0104 chemical sciences ,Solvent ,chemistry.chemical_compound ,Montmorillonite ,chemistry ,Specific surface area ,engineering ,Organic chemistry ,Physical and Theoretical Chemistry ,Selectivity - Abstract
A number of acid-modified clays (halloysite, montmorillonite, illite) were studied as catalysts for isoprenol cyclization with isovaleraldehyde to tetrahydropyranols used in perfumery as a mixture of cis- and trans- isomers. The main attention was paid to properties of halloysite nanotubes after treating them with 5% HCl at temperatures from 30 to 100 °C. The catalysts were characterized by XRD, EDX, MAS NMR, SEM, and N2 adsorption-desorption methods. The acid modification of halloysite allows an efficient increase of its acidity and specific surface area, while preserving morphology of nanotubes. On relatively weakly acidic clays, the formation of the target product occurs through a hemiacetal as a precursor. On the contrary, over strongly acidic resin Amberlyst-15, the yield of tetrahydropyranol was significantly lower because of a direct formation of tetrahydropyranols and dehydration by-products. The yield of tetrahydropyranol in the presence of clays was 65–72 %, slightly increasing with an increase in their acidity. The selectivity towards the cis- isomer did not practically depend on the acid sites concentration in clays, decreasing slightly for the trans-isomer with decreasing acidity due to formation of the dehydration by-products. In general, acid-modified clays are promising catalysts for the preparation of tetrahydropyranols under mild conditions and in the absence of any solvent.
- Published
- 2021
44. Anisotropic thin films formation rate on PEDOT : PSS layer with high azimuthal anchoring
- Author
-
Vladimir Agabekov, Andrei Stankevich, Alexander Muravsky, Veronika Bezruchenko, and Anatoli Murauski
- Subjects
Organic electronics ,Materials science ,business.industry ,Anchoring ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,PEDOT:PSS ,Coating ,engineering ,Optoelectronics ,Contrast ratio ,Electrical and Electronic Engineering ,Thin film ,0210 nano-technology ,business ,Layer (electronics) ,Common emitter - Abstract
Oriented organic layers have great potential for organic electronics devices because of the unique modification of material properties without extensive chemical synthesis. Such layers can be prepared by wet coating of anisotropic organic molecules on top of specific surface of alignment layer. One of the most important parameter that indicates alignment properties of the surface is the anchoring energy. In this paper, we investigate azimuthal anchoring energy of pure and glycerol-doped PEDOT : PSS layers and study the influence of the alignment layer preparation on the order parameter of the top wet-coated oriented organic emitter. We confirm that the azimuthal anchoring energy increase leads to improvement of both dichroic ratio and contrast ratio of polarized emitter layer rod-coated on top of the PEDOT : PSS. Suggested mechanism of anisotropic emitter formation at wet deposition grounds possibility of linear deposition rate of 2 m/s on top of PEDOT : PSS layer with obtained azimuthal anchoring above >10−4 J/m2.
- Published
- 2016
45. Photoalignment of a Bisazodioxodibenzothiophene in a Polyvinylpyrrolidone Matrix
- Author
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Vladimir Agabekov, V. S. Mikulich, S. N. Larykava, J. D. Chaplanova, and E. A. Gracheva
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010302 applied physics ,Spin coating ,Aqueous solution ,010304 chemical physics ,Polyvinylpyrrolidone ,Chemistry ,Condensed Matter Physics ,Dichroic glass ,Photochemistry ,01 natural sciences ,Cis trans isomerization ,0103 physical sciences ,medicine ,Irradiation ,Thin film ,Isomerization ,Spectroscopy ,Nuclear chemistry ,medicine.drug - Abstract
Photoalignment of thin films of dipotassium 3,7-bis[1-(4-hydroxy-3-carboxylate)phenylazo]-5,5′-dioxodibenzothiophene (AtA-2) that were prepared by spin-coating of dye solutions in H2O and DMF and aqueous solutions of polyvinylpyrrolidone (PVP) was studied. The UV absorption band of the dye cis-isomer, the position and intensity of which depended on the PVP concentration in the stock solutions, was recorded upon irradiation of films of AtA-2 in a PVP matrix [AtA-2(PVP)] with unfi ltered light from a DRT-1000 lamp in a vacuum or an Ar atmosphere. PVP facilitated trans–cis isomerization of AtA-2 and increased the stability of the cis-isomer with respect to thermal relaxation into the initial trans-isomer. The dichroic ratio (DR) of AtA-2(PVP) films irradiated with linearly polarized light (blue LED with λ = 450 nm, I = 15 mW/cm2) increased by 1.5 times as the PVP concentration in the stock solutions increased from 1.0 to 10.0 mass%. The morphology and roughness of the films depended on the nature of the solvents used to prepare them.
- Published
- 2016
46. Associates of thioalkyl derivatives of 2-arylaminopyrimidine with hydroxyapatite-based nanocomposites
- Author
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A. V. Pietkievich, A. N. Eryomin, Yu. V. Siniutsich, A. V. Abakshonok, Zh. V. Ignatovich, Vladimir Agabekov, and Muhanna K. Al-Muhanna
- Subjects
Sh groups ,Nanocomposite ,010405 organic chemistry ,Chemistry ,Nanoparticle ,Treatment method ,General Chemistry ,030226 pharmacology & pharmacy ,01 natural sciences ,0104 chemical sciences ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Chemisorption ,Nanocarriers ,Magnetite ,Nuclear chemistry - Abstract
Co-precipitation and ultrasonic treatment methods have been used for the in situ formation of the composites of hydroxyapatite (HA) covered with nanoparticles of magnetite as well as compositions of magnetite, gold and silver. The thioalkyl-substituted derivatives of 2-arylaminopyrimidine, structural analogs of antitumor drug Imatinib containing one or two SH groups and capable to chemisorption on hydroxyapatite and its nanocomposites, have been synthesized. Two-component Fe3O4(HA) and three-component Fe3O4(HA)Au and Fe3O4(HA)Ag composites have been found the most promising as nanocarriers of bioactive compounds.
- Published
- 2016
47. Influence of Methyl Substituents on Azo-Dye Photoalignment in Thin Films
- Author
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V. S. Mikulich, Al. A. Muravsky, Vladimir Agabekov, and An. A. Murawski
- Subjects
Materials science ,Plane (geometry) ,Potassium ,Substituent ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Photochemistry ,01 natural sciences ,010309 optics ,chemistry.chemical_compound ,chemistry ,0103 physical sciences ,Structural isomer ,Molecule ,Irradiation ,Thin film ,0210 nano-technology ,Layer (electronics) ,Spectroscopy - Abstract
Photoalignment of azo dyes derived from salicylic acid in thin films (80–200 nm) was studied upon irradiation with polarized light (λmax = 457 nm). It is shown that different trends of molecular reorientation, i.e., in the layer plane or orthogonal to it, are observed depending on the position of the methyl substituent in the dye structure. A new distribution parameter Z that allows the portion of molecules reoriented in the layer plane during exposure to be determined is introduced. The novel azo dye potassium 3,7-bis[1-(4-hydroxy-3-carboxylate)phenylazo]-5,5′-dioxodibenzothiophene was synthesized. Its molecules are photoaligned in the layer plane upon irradiation with polarized light.
- Published
- 2016
48. Effect of temperature on the photoalignment of azo dyes in thin films
- Author
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Al. A. Muravsky, An. A. Murauski, V. S. Mikulich, and Vladimir Agabekov
- Subjects
Materials science ,Molecule ,02 engineering and technology ,Irradiation ,Physical and Theoretical Chemistry ,Thin film ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,Dichroic glass ,Photochemistry ,01 natural sciences ,0104 chemical sciences - Abstract
The temperature dependences of the induced dichroic ratios (DRs) of azo dyes after their photoalignment in thin films 80 to 200 nm thick are studied. It is found that the DR values of layers containing dyes of the benzeneazodiphenyl series fall from 6.0 to 1.6 as the temperature rises from 60 to 130°C, respectively. A reduction in induced DR as the temperature rises (from 20 to 100°C) is also observed for the thin films of the dyes of benzeneazo-5,5’-dioxodibenzothiophene group. The absence of induced DR after irradiation with polarized light at 100°C indicates there is no alignment of molecules at this temperature.
- Published
- 2016
49. Broad band thermostable polarizing film based on poly (vinyl alcohol), a quinoline derivative and ZnO nanoparticles
- Author
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H. A. Almodarresiyeh, Rakesh Kumar, Vladimir Agabekov, Siyamak Shahab, Anatoliy Lugovsky, and Liudmila Filippovich
- Subjects
chemistry.chemical_classification ,Vinyl alcohol ,Materials science ,General Chemical Engineering ,Quinoline ,02 engineering and technology ,General Chemistry ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Dichroic glass ,01 natural sciences ,Polyvinyl alcohol ,0104 chemical sciences ,chemistry.chemical_compound ,Crystallography ,Thermal conductivity ,chemistry ,Organic chemistry ,0210 nano-technology ,Anisotropy ,Derivative (chemistry) - Abstract
In the present study, for the first time on the basis of polyvinyl alcohol (PVA), dichroic dyes: (sodium 4-[(4E)-4-[(2E)-2-(2-chloro-3-{(E)-2-[1-(4-sulfonatobutyl)quinolinium-4-yl]ethenyl}-2,3-dihydro-1H-inden-1-ylidene)ethylidene]quinolin-1(4H)-yl]butane-1-sulfonate) (I), 6-amino-4-hydroxy-3-((4-(phenyldiazenyl)phenyl)diazenyl)naphthalene-2-sulfonic acid (II), and Chicago Sky Blue (III) broad band thermostable polarizing PVA-films were created. The obtained polarizing PVA-films had polarizing efficiencies (PEs) in the range of 97–99% in UV-Vis (300–695 nm) and PEs of 90–96% in the near IR (819–855 nm) regions of the spectrum. The photostability of the films could be improved by ZnO nanoparticles (average length ∼ 1 μm and diameter ∼ 85 nm) incorporated in a polymer matrix. Apparently, ZnO NPs act as a stabilizer in the photochemical process of dye degradation. During the study, it was established that oriented broad band PVA-films are a phenomenon of the anisotropy of thermal conductivity (λ‖/λ⊥). This is very important for the existence of thermostable polarizing PVA-films. It was also found that in the films the thermal conductivity in the direction of orientation (λ‖) was higher than in a direction perpendicular to the orientation (λ⊥).
- Published
- 2016
50. Preparation of stable sols of silver nanoparticles in aqueous pectin solutions and properties of the sols
- Author
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Muhanna K. Al-Muhanna, A. N. Kraskouski, Kseniya Hileuskaya, Viktoryia Kulikouskaya, and Vladimir Agabekov
- Subjects
Aqueous solution ,food.ingredient ,Materials science ,Pectin ,Inorganic chemistry ,Nanoparticle ,Surfaces and Interfaces ,Silver nanoparticle ,Colloid and Surface Chemistry ,food ,Chemical engineering ,Transmission electron microscopy ,Reagent ,Particle ,Physical and Theoretical Chemistry ,Surface plasmon resonance - Abstract
Silver nanoparticles have been synthesized by reducing AgNO3 in an alkaline medium under the action of a natural polysaccharide, pectin. The influences of the type of pectin used and the reagent mixing order during the synthesis on the sizes and plasmon resonance properties of nanoparticles have been studied by optical spectroscopy and transmission electron microscopy. The conditions that make it possible to obtain silver hydrosols having predetermined particle sizes of 8 ± 2 to 22 ± 6 nm and stable to aggregation for at least 3 months have been determined.
- Published
- 2015
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