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Authors = Vladimir Volkov ORCID = 0000-0003-1106-2947

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16 pages, 1493 KiB  
Article
Baseline Radiomics as a Prognostic Tool for Clinical Benefit from Immune Checkpoint Inhibition in Inoperable NSCLC Without Activating Mutations
by Fedor Moiseenko, Marko Radulovic, Nadezhda Tsvetkova, Vera Chernobrivceva, Albina Gabina, Any Oganesian, Maria Makarkina, Ekaterina Elsakova, Maria Krasavina, Daria Barsova, Elizaveta Artemeva, Valeria Khenshtein, Natalia Levchenko, Viacheslav Chubenko, Vitaliy Egorenkov, Nikita Volkov, Alexei Bogdanov and Vladimir Moiseyenko
Cancers 2025, 17(11), 1790; https://doi.org/10.3390/cancers17111790 - 27 May 2025
Viewed by 501
Abstract
Background/Objectives: Checkpoint inhibitors (ICIs) are key therapies for NSCLC, but current selection criteria, such as excluding mutation carriers and assessing PD-L1, lack sensitivity. As a result, many patients receive costly treatments with limited benefit. Therefore, this study aimed to predict which NSCLC patients [...] Read more.
Background/Objectives: Checkpoint inhibitors (ICIs) are key therapies for NSCLC, but current selection criteria, such as excluding mutation carriers and assessing PD-L1, lack sensitivity. As a result, many patients receive costly treatments with limited benefit. Therefore, this study aimed to predict which NSCLC patients would achieve durable survival (≥24 months) with immunotherapy. Methods: A comprehensive ensemble radiomics approach was applied to pretreatment CT scans to prognosticate overall survival (OS) and predict progression-free survival (PFS) in a cohort of 220 consecutive patients with inoperable NSCLC treated with first-line ICIs (pembrolizumab or atezolizumab, nivolumab or prolgolimab) as monotherapy or in combination. The radiomics pipeline evaluated four normalization methods (none, min-max, Z-score, mean), four feature selection techniques (ANOVA, RFE, Kruskal–Wallis, Relief), and ten classifiers (e.g., SVM, random forest). Using two to eight radiomics features, 1680 models were built in the Feature Explorer (FAE) Python package. Results: Three feature sets were evaluated: clinicopathological (CP) only, radiomics only, and a combined set, using 6- and 12-month PFS and 24-month OS endpoints. The top 15 models were ensembled by averaging their probability scores. The best performance was achieved at 24-month OS with the combined CP and radiomics ensemble (AUC = 0.863, accuracy = 85%), followed by radiomics-only (AUC = 0.796, accuracy = 82%) and CP-only (AUC = 0.671, accuracy = 76%). Predictive performance was lower for 6-month (AUC = 0.719) and 12-month PFS (AUC = 0.739) endpoints. Conclusions: Our radiomics pipeline improved selection of NSCLC patients for immunotherapy and could spare non-responders unnecessary toxicity while enhancing cost-effectiveness. Full article
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13 pages, 726 KiB  
Data Descriptor
A Non-Binary Approach to Super-Enhancer Identification and Clustering: A Dataset for Tumor- and Treatment-Associated Dynamics in Mouse Tissues
by Ekaterina D. Osintseva, German A. Ashniev, Alexey V. Orlov, Petr I. Nikitin, Zoia G. Zaitseva, Vladimir V. Volkov and Natalia N. Orlova
Data 2025, 10(5), 74; https://doi.org/10.3390/data10050074 - 14 May 2025
Viewed by 510
Abstract
Super-enhancers (SEs) are large clusters of highly active enhancers that play key regulatory roles in cell identity, development, and disease. While conventional methods classify SEs in a binary fashion—super-enhancer or not—this threshold-based approach can overlook significant intermediate states of enhancer activity. Here, we [...] Read more.
Super-enhancers (SEs) are large clusters of highly active enhancers that play key regulatory roles in cell identity, development, and disease. While conventional methods classify SEs in a binary fashion—super-enhancer or not—this threshold-based approach can overlook significant intermediate states of enhancer activity. Here, we present a dataset and accompanying framework that facilitate a more nuanced, non-binary examination of SE activation across mouse tissue types (mammary gland, lung tissue, and NMuMG cells) and various experimental conditions (normal, tumor, and drug-treated samples). By consolidating overlapping SE intervals and capturing continuous enhancer activity metrics (e.g., ChIP-seq signal intensities), our dataset reveals gradual transitions between moderate and high enhancer activity levels that are not captured by strictly binary classification. Additionally, the data include extensive functional annotations, linking SE loci to nearby genes and enabling immediate downstream analyses such as clustering and gene ontology enrichment. The flexible approach supports broader investigations of enhancer landscapes, offering a comprehensive platform for understanding how SE activation underpins disease mechanisms, therapeutic response, and developmental processes. Full article
(This article belongs to the Special Issue Benchmarking Datasets in Bioinformatics, 2nd Edition)
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21 pages, 4982 KiB  
Article
New Explosive-Circulation Technology of Tire Recycling for the Production of Crumb Rubber with Modified Surface
by Vyacheslav M. Misin, Alexander A. Nabok, Alexander A. Zakharov, Alexey V. Krivandin, Natalia I. Krikunova, Vladimir A. Volkov, Mikhail V. Voronkov, Sergey I. Pozin, Alexey K. Buryak, Alexander E. Tarasov, Alexander V. Naumkin and Sergey S. Nikulin
Polymers 2025, 17(9), 1260; https://doi.org/10.3390/polym17091260 - 5 May 2025
Viewed by 800
Abstract
The article reports on the development of a fundamentally new, effective technology for recycling waste tires using the explosive-circulation technology method, which was implemented in industry at a working factory. The construction of an explosion-circulation reactor, in which tires are destroyed under the [...] Read more.
The article reports on the development of a fundamentally new, effective technology for recycling waste tires using the explosive-circulation technology method, which was implemented in industry at a working factory. The construction of an explosion-circulation reactor, in which tires are destroyed under the influence of an explosion, is described. The main technological stages of the reactor operation include the formation of a tire package with a height of about 2.4 m and a mass of up to 1000 kg; cooling the package by air turbo-cooling machine to a temperature of minus 70–80 °C; placing the package into the reactor; initiating the explosive charge; and removing the tire shedding products with a subsequent granulometric classification of the resulting rubber crumb. The resulting rubber crumb has good wettability, which eliminates the need for an additional technological stage of activating the crumb surface. This made it possible to successfully use the obtained rubber crumb to improve the characteristics of road construction bitumen, the hardness of which at −16 °C decreased from 217 to 161 MPa. Using atomic force microscopy (AFM), gas chromatography, mass spectrometry, GPC, and XPS, it was established that the good wettability of the crumbs is explained by the formation of molecules with polar groups (C-O, C=O, C(O)O, C-S, C-SOx, Zn-S, O-Si(O)-O) on the crumb surface as a result of the explosion. Full article
(This article belongs to the Section Circular and Green Sustainable Polymer Science)
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15 pages, 6621 KiB  
Article
Hydrophobic GeO2 Aerogels by an Epoxide-Induced Process
by Olga M. Gajtko, Svetlana V. Golodukhina, Sergey Yu. Kottsov, Elena N. Subcheva, Vladimir V. Volkov, Gennady P. Kopitsa, Alexandra G. Son and Varvara O. Veselova
Gels 2025, 11(4), 225; https://doi.org/10.3390/gels11040225 - 22 Mar 2025
Cited by 1 | Viewed by 629
Abstract
This article reports a new straightforward method for producing hydrophobic GeO2 aerogels in a one-pot synthesis. For the first time, the epoxide-induced sol–gel process was combined with the co-precursor method to create hydrophobic aerogels. The application of a complex of analytical methods [...] Read more.
This article reports a new straightforward method for producing hydrophobic GeO2 aerogels in a one-pot synthesis. For the first time, the epoxide-induced sol–gel process was combined with the co-precursor method to create hydrophobic aerogels. The application of a complex of analytical methods like SEM, TEM, low-temperature nitrogen adsorption–desorption, SAXS and contact angle measurements enabled us to determine that varying the GeCl4:(C2H5)2GeCl2 ratio allows for targeted adjustments in the morphology, porous structure, and surface properties of aerogels. As the proportion of (C2H5)2GeCl2 grows, the surface area increases from 45 to 123 m2∙g−1 and the contact angle changes from 22.1 to 140.1°. Luminescent properties of the hydrophobic GeO2 aerogels are reported for the first time, and it is established that the ratio of green and blue bands in the luminescence spectra when excited under 390 and 235 nm varies depending on the GeCl4:(C2H5)2GeCl2 ratio used for the aerogel preparation. Full article
(This article belongs to the Special Issue Synthesis and Application of Aerogel)
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13 pages, 2059 KiB  
Article
Increasing the Permeability of Polyphenylene Sulfone Hollow Fiber Ultrafiltration Membranes by Switching the Polymer End Groups
by Alisa Raeva, Dmitry Matveev, Tatyana Anokhina, Azamat A. Zhansitov, Svetlana Khashirova, Vladimir Volkov and Ilya Borisov
Polymers 2025, 17(1), 53; https://doi.org/10.3390/polym17010053 - 29 Dec 2024
Viewed by 951
Abstract
The influence of the molecular weight and chemical structure of polyphenylene sulfone (PPSU) end groups on the formation of the porous structure of ultrafiltration (UF) hollow fiber membranes was investigated. Polymers with a molecular weight ranging from 67 to 81 kg/mol and with [...] Read more.
The influence of the molecular weight and chemical structure of polyphenylene sulfone (PPSU) end groups on the formation of the porous structure of ultrafiltration (UF) hollow fiber membranes was investigated. Polymers with a molecular weight ranging from 67 to 81 kg/mol and with a hydroxyl-to-chlorine end group ratio ranging from 0.43 to 17.0 were synthesized. The excess of end groups was achieved during polymer synthesis by adding one of the following monomers: hydroxyl (excess DHBP) or chlorine (excess DCDPS). For the first time, it was found that the stability of PPSU solutions is determined not by the molecular weight of the polymer, but by the chemical structure of its end groups. The stability of polymer solutions increases with the increasing proportion of chlorine groups. The SEM method showed that with the increasing molar fraction of chlorine end groups in the polymer, a more open porous structure forms on the outer surface of the hollow fiber membranes derived from it. The maximum UF permeance of the hollow fiber membranes for water was achieved with the PPSU sample containing the highest chlorine end group content, amounting to 136 L/(m2·h·bar), with a high rejection of the model substance Blue Dextran (at 94.7%). This represents the best result currently reported among unmodified PPSU hollow fiber membranes. Full article
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25 pages, 6110 KiB  
Article
High-Performance Porous Supports Based on Hydroxyl-Terminated Polysulfone and CO2/CO-Selective Composite Membranes
by Dmitry Matveev, Tatyana Anokhina, Alisa Raeva, Ilya Borisov, Evgenia Grushevenko, Svetlana Khashirova, Alexey Volkov, Stepan Bazhenov, Vladimir Volkov and Anton Maksimov
Polymers 2024, 16(24), 3453; https://doi.org/10.3390/polym16243453 - 10 Dec 2024
Viewed by 1156
Abstract
The scope of this work was to develop a thin-film composite (TFC) membrane for the separation of CO2/CO mixtures, which are relevant for many processes of gas processing and gasification of carbon-based feedstock. Special attention was given to the development of [...] Read more.
The scope of this work was to develop a thin-film composite (TFC) membrane for the separation of CO2/CO mixtures, which are relevant for many processes of gas processing and gasification of carbon-based feedstock. Special attention was given to the development of highly permeable porous polysulfone (PSF) supports (more than 26,000 GPU for CO2) since both the selective and support layers contribute significantly to the overall performance of the TFC membrane. The PSF porous support is widely used in commercial and lab-scale TFC membranes, and its porous structure and other exploitation parameters are set during the non-solvent-induced phase separation (NIPS) process. Since the casting solution properties (e.g., viscosity) and the interactions in a three-component system (polymer, solvent, and non-solvent) play noticeable roles in the NIPS process, polysulfone samples in a wide range of molecular weights (Mw = 76,000–122,000 g·mol−1) with terminal hydroxyl groups were synthesized for the first time. Commercial PSF with predominantly terminal chlorine groups (Ultrason® S 6010) was used as a reference. The PSF samples were characterized by NMR, DSC, and TGA methods, and the Hansen solubility parameters were calculated. It was found that increasing the ratio of terminal –OH over –Cl groups improved the “solubility” of PSF in N-methyl-2-pyrrolidone (NMP) and water. A direct dependence of the gas permeance of porous supports on the coagulation rate of the casting solution was identified for the first time. It was shown that the use of synthesized PSF (Mw = 76,000 g·mol−1, Mw/Mn = 3.0, (–OH):(–Cl) ratio of 4.7:1) enabled a porous support with a CO2 permeance of 26,700 GPU to be obtained, while the support formed from a commercial PSF Ultrason® S 6010 (Mw = 68,000 g·mol−1, Mw/Mn = 1.7, (–OH):(–Cl) ratio of 1:1.9) under the same conditions demonstrated 4300 GPU. The siloxane-based materials were used for the selective layer since the thin films based on rubbery polymers do not undergo the same accelerating physical aging as glassy polymers. Two types of materials were screened for the selective layer: synthesized polymethyltrifluoroethylacrylate siloxane-polydecylmethylsiloxane (50F3) copolymer, and polydimethylsiloxane (PDMS). 50F3 siloxane was studied for gas separation applications for the first time. It was shown that the permeance of composite membranes based on high-performance porous supports from the PSF samples synthesized was 3.5 times higher than that from similar composite membranes based on supports from a commercial Ultrason® S 6010 PSF with a permeance value of 4300 GPU for CO2. It was found that the enhanced gas permeance of composite membranes based on the highly permeable porous PSF supports developed was observed for both 50F3 polysiloxane and commercial PDMS. At the same time, the CO2/CO selectivity of the composite membranes with a 50F3-selective layer (9.1–9.3) is 1.5 times higher than that of composite membranes with a PDMS-selective layer. This makes the F-containing 50F3 polysiloxane a promising polymer for CO2/CO separation. Full article
(This article belongs to the Section Polymer Membranes and Films)
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24 pages, 9382 KiB  
Article
Polyacrylonitrile Ultrafiltration Membrane for Separation of Used Engine Oil
by Alexandra Nebesskaya, Anastasia Kanateva, Roman Borisov, Alexey Yushkin, Vladimir Volkov and Alexey Volkov
Polymers 2024, 16(20), 2910; https://doi.org/10.3390/polym16202910 - 16 Oct 2024
Cited by 3 | Viewed by 1817
Abstract
The separation of used engine oil (UEO) with an ultrafiltration (UF) membrane made of commercial copolymer of poly(acrylonitrile-co-methyl acrylate) (P(AN-co-MA)) has been investigated. The P(AN-co-MA) sample was characterized by using FTIR spectroscopy, 13C NMR spectroscopy, and XRD. The UF membrane with a [...] Read more.
The separation of used engine oil (UEO) with an ultrafiltration (UF) membrane made of commercial copolymer of poly(acrylonitrile-co-methyl acrylate) (P(AN-co-MA)) has been investigated. The P(AN-co-MA) sample was characterized by using FTIR spectroscopy, 13C NMR spectroscopy, and XRD. The UF membrane with a mean pore size of 23 nm was fabricated by using of non-solvent-induced phase separation method—the casting solution of 13 wt.% P(AN-co-MA) in dimethylsulfoxide (DMSO) was precipitated in the water bath. Before the experiment, the used engine oil was diluted with toluene, and the resulting UEO solution in toluene (100 g/L) was filtered through the UF membrane in the dead-end filtration mode. Special attention was given to the evaluation of membrane fouling; for instance, the permeability of UEO solution was dropped from its initial value of 2.90 L/(m2·h·bar) and then leveled off at 0.75 L/(m2·h·bar). However, the membrane cleaning (washing with toluene) allowed a recovery of 79% of the initial pure toluene flux (flux recovery ratio), indicating quite attractive membrane resistance toward irreversible fouling with engine oil components. The analysis of the feed, retentate, and permeate by various analytical methods showed that the filtration through the UF membrane made of P(AN-co-MA) provided the removal of major contaminants of used engine oil including polymerization products and metals (rejection—96.3%). Full article
(This article belongs to the Section Polymer Membranes and Films)
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15 pages, 7956 KiB  
Article
Modeling the Stress–Strain State of a Filled Human Bladder
by Marina Barulina, Tatyana Timkina, Yaroslav Ivanov, Vladimir Masliakov, Maksim Polidanov and Kirill Volkov
Appl. Sci. 2024, 14(17), 7562; https://doi.org/10.3390/app14177562 - 27 Aug 2024
Cited by 2 | Viewed by 1770
Abstract
In this paper, the problems of modeling the human bladder and its stress–strain state under an external static influence are considered. A method for the identification of the anisotropic biomechanical characteristics of the bladder tissue is proposed. An FEM model was created, which [...] Read more.
In this paper, the problems of modeling the human bladder and its stress–strain state under an external static influence are considered. A method for the identification of the anisotropic biomechanical characteristics of the bladder tissue is proposed. An FEM model was created, which takes into account the fact that the bladder is surrounded by fiber, affected by surrounding organs, and partially protected by pelvic bones. The model considers the presence of constant hydrostatic pressure on the walls of the bladder when it is full. It has been shown that the isotropic mechanical characteristics of biological tissue can be used for studying the deformed state of a filled bladder if a filled bladder of 300 mL is considered as the initial non-deformed stage. This was shown by the modeling and verification of the effect of the external static force on the bladder. Numerical experiments were conducted based on the constructed model. To validate the results obtained, a series of natural experiments on the effect of external pressure on the bladder under ultrasound control were conducted. In the future, there are plans to use the constructed model to study rupture deformations of the bladder under the influence of static and dynamic loads. Full article
(This article belongs to the Special Issue Advances in Bioinformatics and Biomedical Engineering)
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16 pages, 3061 KiB  
Article
Time-Dependent Shifts in Intestinal Bacteriome, Klebsiella Colonization and Incidence of Antibiotic-Resistance Genes after Allogeneic Hematopoietic Stem Cell Transplantation
by Oleg V. Goloshchapov, Alexey B. Chukhlovin, Dmitrii E. Polev, Yury A. Eismont, Dmitry S. Bug, Alexey V. Kusakin, Oleg V. Kosarev, Ruslana V. Klementeva, Vladimir V. Gostev, Vladimir A. Ageevets, Nikita P. Volkov, Anastasia S. Ipatova, Ivan S. Moiseev, Anna A. Spiridonova, Sergey V. Sidorenko and Alexander D. Kulagin
Biomedicines 2024, 12(7), 1566; https://doi.org/10.3390/biomedicines12071566 - 15 Jul 2024
Viewed by 2317
Abstract
Dose-intensive cytostatic therapy and antibiotic treatment in allogeneic hematopoietic stem cell transplantation (allo-HSCT) cause severe abnormalities in a composition of gut microbiota as well as the emergence of antibiotic resistance. The data on the longitudinal recovery of major bacterial phyla and the expansion [...] Read more.
Dose-intensive cytostatic therapy and antibiotic treatment in allogeneic hematopoietic stem cell transplantation (allo-HSCT) cause severe abnormalities in a composition of gut microbiota as well as the emergence of antibiotic resistance. The data on the longitudinal recovery of major bacterial phyla and the expansion of genes associated with antibiotic resistance are limited. We collected regular stool samples during the first year after allo-HSCT from 12 adult patients with oncohematological disorders after allo-HSCT and performed 16SrRNA sequencing, multiplex PCR, conventional bacteriology and CHROMagar testing. We observed a decline in Shannon microbiota diversity index as early as day 0 of allo-HSCT (p = 0.034) before any administration of antibiotics, which persisted up to 1 year after transplantation, when the Shannon index returned to pre-transplant levels (p = 0.91). The study confirmed the previously shown decline in Bacillota (Firmicutes) genera and the expansion of E. coli/Shigella, Klebsiella and Enterococci. The recovery of Firmicutes was slower than that of other phyla and occurred only a year post-transplant. A positive correlation was observed between the expansion of E. coli/Shigella genera and blaKPC, blaCTX-M-1 and blaTEM (p < 0.001), Klebsiella spp. and blaOXA-48-like, blaNDM, blaCTX-M-1, blaTEM, and blaSHV (p < 0.001), Pseudomonas spp. and blaNDM (p = 0.002), Enterococcus spp. and blaOXA-48-like, blaNDM, blaCTX-M-1, blaSHV (p < 0.01). The correlation was observed between the expansion of Enterobacterales and and carbapenemase-positive CHROMagar samples (p < 0.001). Samples positive for carbapenem-resitant bacteria were at their maximum levels on day +30, and were gradually diminishing one year after allo-HSCT. From day +30 to +60, all isolated K. pneumoniae strains in fecal samples proved to be resistant to the main antibiotic groups (carbapenems, aminoglycosides, fluoroquinolones, third-generation cephalosporins). One year after HSCT, we documented the spontaneous decolonization of K. pneumoniae. The sensitivity of molecular biology techniques in the search for total and antibiotic-resistant Klebsiella seems to be superior to common bacteriological cultures. Future studies should be focused on searching for novel approaches to the efficient reconstitution and/or maintenance of strictly anaerobic microbiota in oncological patients. Full article
(This article belongs to the Special Issue Impact of Microbiota in Response to Therapy)
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17 pages, 11586 KiB  
Article
Humic Polyelectrolytes Facilitate Rapid Microwave Synthesis of Silver Nanoparticles Suitable for Wound-Healing Applications
by Yu Zhang, Konstantin S. Larionov, Simeng Zhang, Nikita A. Sobolev, Andrey I. Konstantinov, Dmitry S. Volkov, Evgeniya V. Suslova, Vladimir E. Chernov, Anton I. Poloskov, Ruslan I. Glushakov and Irina V. Perminova
Polymers 2024, 16(5), 587; https://doi.org/10.3390/polym16050587 - 21 Feb 2024
Cited by 7 | Viewed by 2029
Abstract
This article describes the one-pot microwave synthesis of silver nanoparticles (AgNPs) assisted with natural polyelectrolytes—humic substances (HS). The humic polyelectrolytes served both as chemical reductants for silver ions and as end-capping agents for AgNPs. Three commercially available sodium humates extracted from lignites and [...] Read more.
This article describes the one-pot microwave synthesis of silver nanoparticles (AgNPs) assisted with natural polyelectrolytes—humic substances (HS). The humic polyelectrolytes served both as chemical reductants for silver ions and as end-capping agents for AgNPs. Three commercially available sodium humates extracted from lignites and leonardite and one sodium fulvate isolated from natural brown water seeped through peat deposits were used in this study. The dynamics of the growth rate of AgNPs was characterised by UV–VIS spectroscopy by measuring the intensity of surface plasmon resonance at 420 nm. Transmission electron microscopy was used to characterise the size and morphology of AgNPs. Dynamic light scattering was used to determine size distributions of the synthesised AgNPs in the solutions. It was established that both conventional and microwave syntheses assisted with the coal humates produced small-size AgNPs in the range from 4 to 14 nm, with the maximum share of particles with sizes of (6 ± 2) nm by TEM estimates. The peat fulvate yielded much larger NPs with sizes from 10 to 50 nm by TEM estimates. DLS measurements revealed multimodal distributions of AgNPs stabilised with HS, which included both single NPs with the sizes from 5 to 15 nm, as well as their dominating aggregates with sizes from 20 to 200 nm and a smaller portion of extra-large aggregates up to 1000 nm. The given aggregates were loosely bound by humic polyelectrolyte, which prevented the coalescence of AgNPs into larger particles, as can be seen in the TEM images. The significant acceleration in the reaction time—a factor of 60 to 70—was achieved with the use of MW irradiation: from 240 min down to 210–240 s. The coal humate stabilised AgNPs showed antimicrobial properties in relation to S. aureus. A conclusion was made regarding the substantial advantages of microwave synthesis in the context of time and scaling up for the large-scale production of AgNP-HS preparations with antimicrobial properties suitable for external wound-healing applications. Full article
(This article belongs to the Special Issue Advances in Polyelectrolytes and Polyelectrolyte Complexes)
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10 pages, 2904 KiB  
Article
Comprehensive Recovery of Point Defect Displacement Field Function in Crystals by Computer X-ray Diffraction Microtomography
by Felix N. Chukhovskii, Petr V. Konarev and Vladimir V. Volkov
Crystals 2024, 14(1), 29; https://doi.org/10.3390/cryst14010029 - 26 Dec 2023
Viewed by 1680
Abstract
In the case of the point defect in a crystal, the inverse Radon’s problem in X-ray diffraction microtomography has been solved. As is known, the crystal-lattice defect displacement field function f(r) = h·u(r) determines phases [...] Read more.
In the case of the point defect in a crystal, the inverse Radon’s problem in X-ray diffraction microtomography has been solved. As is known, the crystal-lattice defect displacement field function f(r) = h·u(r) determines phases − (±h)-structure factors incorporated into the Takagi–Taupin equations and provides the 2D image patterns by diffracted and transmitted waves propagating through a crystal (h is the diffraction vector and u(r) is the displacement field crystal-lattice-defects vector). Beyond the semi-kinematical approach for obtaining the analytical problem solution, the difference-equations-scheme of the Takagi–Taupin equations that, in turn, yield numerically controlled-accuracy problem solutions has been first applied and tested. Addressing the inverse Radon’s problem solution, the χ2-target function optimization method using the Nelder–Mead algorithm has been employed and tested in an example of recovering the Coulomb-type point defect structure in a crystal Si(111). As has been shown in the cases of the 2D noise-free fractional and integrated image patterns, based on the Takagi–Taupin solutions in the semi-kinematical and difference-scheme approaches, both procedures provide the χ2-target function global minimum, even if the starting-values of the point-defect vector P1 is chosen rather far away from the reference up to 40% in relative units. In the cases of the 2D Poisson-noise image patterns with noise levels up to 5%, the figures-of-merit values of the optimization procedures by the Nelder–Mead algorithm turn out to be high enough; the lucky trials number is 85%; and in contrast, for the statistically denoised 2D image patterns, they reach 0.1%. Full article
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28 pages, 18340 KiB  
Article
The AM-4 Family of Layered Titanosilicates: Single-Crystal-to-Single-Crystal Transformation, Synthesis and Ionic Conductivity
by Galina O. Kalashnikova, Sergey V. Krivovichev, Victor N. Yakovenchuk, Ekaterina A. Selivanova, Margarita S. Avdontceva, Gregory Yu. Ivanyuk, Yakov A. Pakhomovsky, Darya V. Gryaznova, Natalya A. Kabanova, Yelizaveta A. Morkhova, Olga Yu. Sinel’shchikova, Vladimir N. Bocharov, Anatoly I. Nikolaev, Olga F. Goychuk, Sergei N. Volkov and Taras L. Panikorovskii
Materials 2024, 17(1), 111; https://doi.org/10.3390/ma17010111 - 25 Dec 2023
Cited by 2 | Viewed by 1942
Abstract
Flexible crystal(水晶) structures, which exhibit(展览) single-crystal(水晶)-to-single-crystal(水晶) (SCSC) transformations(转型), are attracting attention(注意) in many applied aspects: magnetic(磁) switches, catalysis, ferroelectrics and sorption. Acid treatment(治疗) for titanosilicate material(材料) AM-4 and natural(自然) compounds with the same structures led to SCSC transformation(转型) by loss(损失) Na+, [...] Read more.
Flexible crystal(水晶) structures, which exhibit(展览) single-crystal(水晶)-to-single-crystal(水晶) (SCSC) transformations(转型), are attracting attention(注意) in many applied aspects: magnetic(磁) switches, catalysis, ferroelectrics and sorption. Acid treatment(治疗) for titanosilicate material(材料) AM-4 and natural(自然) compounds with the same structures led to SCSC transformation(转型) by loss(损失) Na+, Li+ and Zn2+ cations with large structural(结构) changes (20% of the unit(单位)-cell(细胞) volume(体积)). The conservation(保育) of crystallinity through complex(复杂) transformation(转型) is possible due(由于) to the formation(形成) of a strong hydrogen bonding(债券) system(系统). The mechanism(机制) of transformation(转型) has been characterized using single-crystal(水晶) X-ray(射线) diffraction analysis(分析), powder(粉) diffraction, Rietvield refinement, Raman spectroscopy and electron microscopy. The low migration(迁移) energy(能源) of cations in the considered materials(材料) is confirmed using bond(债券)-valence and density(密度) functional(功能) theory(理论) calculations, and the ion conductivity of the AM-4 family’s materials(材料) has been experimentally verified. Full article
(This article belongs to the Section Porous Materials)
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16 pages, 4539 KiB  
Article
Microfluidically Assisted Synthesis of Calcium Carbonate Submicron Particles with Improved Loading Properties
by Alexey V. Ermakov, Sergei V. Chapek, Ekaterina V. Lengert, Petr V. Konarev, Vladimir V. Volkov, Vladimir V. Artemov, Mikhail A. Soldatov and Daria B. Trushina
Micromachines 2024, 15(1), 16; https://doi.org/10.3390/mi15010016 - 21 Dec 2023
Cited by 7 | Viewed by 2420
Abstract
The development of advanced methods for the synthesis of nano- and microparticles in the field of biomedicine is of high interest due to a range of reasons. The current synthesis methods may have limitations in terms of efficiency, scalability, and uniformity of the [...] Read more.
The development of advanced methods for the synthesis of nano- and microparticles in the field of biomedicine is of high interest due to a range of reasons. The current synthesis methods may have limitations in terms of efficiency, scalability, and uniformity of the particles. Here, we investigate the synthesis of submicron calcium carbonate using a microfluidic chip with a T-shaped oil supply for droplet-based synthesis to facilitate control over the formation of submicron calcium carbonate particles. The design of the chip allowed for the precise manipulation of reaction parameters, resulting in improved porosity while maintaining an efficient synthesis rate. The pore size distribution within calcium carbonate particles was estimated via small-angle X-ray scattering. This study showed that the high porosity and reduced size of the particles facilitated the higher loading of a model peptide: 16 vs. 9 mass.% for the particles synthesized in a microfluidic device and in bulk, correspondingly. The biosafety of the developed particles in the concentration range of 0.08–0.8 mg per plate was established by the results of the cytotoxicity study using mouse fibroblasts. This innovative approach of microfluidically assisted synthesis provides a promising avenue for future research in the field of particle synthesis and drug delivery systems. Full article
(This article belongs to the Special Issue Droplet Microfluidics: Fundamentals and Its Advanced Applications)
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18 pages, 8366 KiB  
Article
Microfluidic Vaterite Synthesis: Approaching the Nanoscale Particles
by Ivan Reznik, Mikhail A. Baranov, Sergei A. Cherevkov, Petr V. Konarev, Vladimir V. Volkov, Stanislav Moshkalev and Daria B. Trushina
Nanomaterials 2023, 13(23), 3075; https://doi.org/10.3390/nano13233075 - 4 Dec 2023
Cited by 6 | Viewed by 2030
Abstract
The challenge of continuous CaCO3 particle synthesis is addressed using microfluidic technology. A custom microfluidic chip was used to synthesize CaCO3 nanoparticles in vaterite form. Our focus revolved around exploring one-phase and two-phase synthesis methods tailored for the crystallization of these [...] Read more.
The challenge of continuous CaCO3 particle synthesis is addressed using microfluidic technology. A custom microfluidic chip was used to synthesize CaCO3 nanoparticles in vaterite form. Our focus revolved around exploring one-phase and two-phase synthesis methods tailored for the crystallization of these nanoparticles. The combination of scanning electron microscopy, X-ray diffraction, dynamic light scattering, and small-angle scattering allowed for an evaluation of the synthesis efficiency, including the particle size distribution, morphology, and polymorph composition. The results demonstrated the superior performance of the two-phase system when precipitation occurred inside emulsion microreactors, providing improved size control compared with the one-phase approach. We also discussed insights into particle size changes during the transition from one-phase to two-phase synthesis. The ability to obtain CaCO3 nanoparticles in the desired polymorph form (∼50 nm in size, 86–99% vaterite phase) with the possibility of scaling up the synthesis will open up opportunities for various industrial applications of the developed two-phase microfluidic method. Full article
(This article belongs to the Special Issue Advanced Manufacturing on Nano- and Microscale)
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18 pages, 1769 KiB  
Article
Properties of Degradable Polyhydroxyalkanoates Synthesized from New Waste Fish Oils (WFOs)
by Natalia O. Zhila, Evgeniy G. Kiselev, Vladimir V. Volkov, Olga Ya. Mezenova, Kristina Yu. Sapozhnikova, Ekaterina I. Shishatskaya and Tatiana G. Volova
Int. J. Mol. Sci. 2023, 24(19), 14919; https://doi.org/10.3390/ijms241914919 - 5 Oct 2023
Cited by 6 | Viewed by 3301
Abstract
The synthesis of PHA was first investigated using WFOs obtained from smoked-sprat heads, substandard fresh sprats, and fresh mackerel heads and backbones. All the WFOs ensured the growth of the wild-type strain Cupriavidus necator B-10646 and the synthesis of PHA, regardless of the [...] Read more.
The synthesis of PHA was first investigated using WFOs obtained from smoked-sprat heads, substandard fresh sprats, and fresh mackerel heads and backbones. All the WFOs ensured the growth of the wild-type strain Cupriavidus necator B-10646 and the synthesis of PHA, regardless of the degree of lipid saturation (from 0.52 to 0.65) and the set and ratio of fatty acids (FA), which was represented by acids with chain lengths from C14 to C24. The bacterial biomass concentration and PHA synthesis were comparable (4.1–4.6 g/L and about 70%) when using WFO obtained from smoked-sprat heads and fresh mackerel, and it was twice as high as the bacterial biomass concentration from the fresh sprat waste. This depended on the type of WFO, the bacteria synthesized P(3HB) homopolymer or P(3HB-co-3HV-co-3HHx) copolymer, which had a lower degree of crystallinity (Cx 71%) and a lower molecular weight (Mn 134 kDa) compared to the P(3HB) (Mn 175–209 kDa and Cx 74–78%) at comparable temperatures (Tmelt and Tdegr of 158–168 °C and 261–284 °C, respectively). The new types of WFO, studied for the first time, are suitable as a carbon substrates for PHA synthesis. The WFOs obtained in the production of canned Baltic sprat and Baltic mackerel can be considered a promising and renewable substrate for PHA biosynthesis. Full article
(This article belongs to the Special Issue Advanced Degradable Biopolymers)
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