492 results on '"Alexander V. Soldatov"'
Search Results
2. Optimal Dynamic Regimes for CO Oxidation Discovered by Reinforcement Learning
- Author
-
Mikhail S. Lifar, Andrei A. Tereshchenko, Aleksei N. Bulgakov, Sergey A. Guda, Alexander A. Guda, and Alexander V. Soldatov
- Subjects
Chemistry ,QD1-999 - Published
- 2024
- Full Text
- View/download PDF
3. Machine Learning Meets Cancer
- Author
-
Elena V. Varlamova, Maria A. Butakova, Vlada V. Semyonova, Sergey A. Soldatov, Artem V. Poltavskiy, Oleg I. Kit, and Alexander V. Soldatov
- Subjects
artificial intelligence ,machine learning ,oncology ,radiomics ,PET/CT ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
The role of machine learning (a part of artificial intelligence—AI) in the diagnosis and treatment of various types of oncology is steadily increasing. It is expected that the use of AI in oncology will speed up both diagnostic and treatment planning processes. This review describes recent applications of machine learning in oncology, including medical image analysis, treatment planning, patient survival prognosis, and the synthesis of drugs at the point of care. The fast and reliable analysis of medical images is of great importance in the case of fast-flowing forms of cancer. The introduction of ML for the analysis of constantly growing volumes of big data makes it possible to improve the quality of prescribed treatment and patient care. Thus, ML is expected to become an essential technology for medical specialists. The ML model has already improved prognostic prediction for patients compared to traditional staging algorithms. The direct synthesis of the necessary medical substances (small molecule mixtures) at the point of care could also seriously benefit from the application of ML. We further review the main trends in the use of artificial intelligence-based technologies in modern oncology. This review demonstrates the future prospects of using ML tools to make progress in cancer research, as well as in other areas of medicine. Despite growing interest in the use of modern computer technologies in medical practice, a number of unresolved ethical and legal problems remain. In this review, we also discuss the most relevant issues among them.
- Published
- 2024
- Full Text
- View/download PDF
4. 3D Printed Microfluidic Cell for SAXS Time-Resolved Measurements of the Structure of Protein Crystallization Solutions
- Author
-
Margarita A. Marchenkova, Sergei V. Chapek, Petr V. Konarev, Ksenia B. Ilina, Georgy S. Peters, Yury V. Pisarevsky, Vladimir A. Shishkov, Alexander V. Soldatov, and Mikhail V. Kovalchuk
- Subjects
synchrotron radiation ,small-angle X-ray scattering ,sample cell ,structure of solutions ,lysozyme ,3D printing ,Crystallography ,QD901-999 - Abstract
A multichannel microfluidic cell (MFC) obtained using 3D printing for studying the structure of complex solutions by small-angle X-ray scattering (SAXS) is described. MFC was tested at the BioMUR beamline of the Kurchatov synchrotron. A comparative analysis of SAXS signal from the standard capillary and from the developed MFC was carried out, with MFC showing significant advantages. The dynamics of SAXS scattering curves for lysozyme solutions with NaCl precipitant were studied when the protein and precipitant concentrations changed. The obtained time series of data are well consistent with the known data for the lysozyme solution.
- Published
- 2023
- Full Text
- View/download PDF
5. Operando Laboratory X-ray Absorption Spectroscopy and UV–Vis Study of Pt/TiO2 Photocatalysts during Photodeposition and Hydrogen Evolution Reactions
- Author
-
Elizaveta G. Kozyr, Peter N. Njoroge, Sergei V. Chapek, Viktor V. Shapovalov, Alina A. Skorynina, Anna Yu. Pnevskaya, Alexey N. Bulgakov, Alexander V. Soldatov, Francesco Pellegrino, Elena Groppo, Silvia Bordiga, Lorenzo Mino, and Aram L. Bugaev
- Subjects
operando spectroscopy ,XANES ,photocatalysis ,platinum catalyst ,UV–Vis ,HER ,Chemical technology ,TP1-1185 ,Chemistry ,QD1-999 - Abstract
Photocatalytic hydrogen (H2) production is a promising route for alternative energetics. Understanding structure–activity relationships is a crucial step towards the rational design of photocatalysts, which requires the application of operando spectroscopy under relevant working conditions. We performed an operando investigation on a catalytic system during the photodeposition of Pt on TiO2 and photostimulated H2 production, using simultaneous laboratory X-ray absorption spectroscopy (XAS), UV–Vis spectroscopy, and mass spectrometry. XAS showed a progressive increase in Pt fluorescence for Pt deposited on TiO2 for over an hour, which is correlated with the signal of the produced H2. The final Pt/TiO2 catalyst contained Pt(0) particles. The electronic features corresponding to the Pt4+ species in the UV–Vis spectrum of the solution disappear as soon as UV radiation is applied in the presence of formic acid, which acts as a hole scavenger, resulting in the presence of Pt(0) particles in solution.
- Published
- 2023
- Full Text
- View/download PDF
6. Online Microfluidic Droplets Characterization Using Microscope Data Intelligent Analysis
- Author
-
Oleg O. Kartashov, Sergey V. Chapek, Dmitry S. Polyanichenko, Grigory I. Belyavsky, Alexander A. Alexandrov, Maria A. Butakova, and Alexander V. Soldatov
- Subjects
computer vision ,Lab-on-Chip ,microfluidic droplet ,synthetic images ,Technology - Abstract
Microfluidic devices have opened new opportunities for functional material chemical synthesis in a few applications. The screening of microfluidic synthesis processes is an urgent task of the experimental process in terms of automation and intellectualization. This study proposes a methodology and software for extracting the morphological and dynamic characteristics of generated monodisperse droplets from video data streams obtained from a digital microscope. For this purpose, the paper considers an approach to generating an extended feature space characterizing the process of droplet generation using a microfluidic device based on the creation of synthetic image datasets. YOLOv7 was used as an algorithm for detecting objects in the images. When training this algorithm, the values in the test dataset mAP@0.5 0.996 were obtained. The algorithms proposed for image processing and analysis implement the basic functionality to extract the morphological and dynamic characteristics of monodisperse droplets in the synthesis process. Laboratory validation and verification of the software demonstrated high results of the identification of key characteristics of the monodisperse droplets generated by the microfluidic device with the average deviation from the real values not exceeding 8%.
- Published
- 2023
- Full Text
- View/download PDF
7. Integrated Video and Acoustic Emission Data Fusion for Intelligent Decision Making in Material Surface Inspection System
- Author
-
Andrey V. Chernov, Ilias K. Savvas, Alexander A. Alexandrov, Oleg O. Kartashov, Dmitry S. Polyanichenko, Maria A. Butakova, and Alexander V. Soldatov
- Subjects
data fusion ,intelligent system ,decision making ,computer vision ,acoustic emission control ,surface inspection ,Chemical technology ,TP1-1185 - Abstract
In the field of intelligent surface inspection systems, particular attention is paid to decision making problems, based on data from different sensors. The combination of such data helps to make an intelligent decision. In this research, an approach to intelligent decision making based on a data integration strategy to raise awareness of a controlled object is used. In the following article, this approach is considered in the context of reasonable decisions when detecting defects on the surface of welds that arise after the metal pipe welding processes. The main data types were RGB, RGB-D images, and acoustic emission signals. The fusion of such multimodality data, which mimics the eyes and ears of an experienced person through computer vision and digital signal processing, provides more concrete and meaningful information for intelligent decision making. The main results of this study include an overview of the architecture of the system with a detailed description of its parts, methods for acquiring data from various sensors, pseudocodes for data processing algorithms, and an approach to data fusion meant to improve the efficiency of decision making in detecting defects on the surface of various materials.
- Published
- 2022
- Full Text
- View/download PDF
8. Deep Learning Classification of Colorectal Lesions Based on Whole Slide Images
- Author
-
Sergey A. Soldatov, Danil M. Pashkov, Sergey A. Guda, Nikolay S. Karnaukhov, Alexander A. Guda, and Alexander V. Soldatov
- Subjects
deep learning ,convolutional neural networks ,whole-slide image ,digital pathology ,colon cancer ,Industrial engineering. Management engineering ,T55.4-60.8 ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
Microscopic tissue analysis is the key diagnostic method needed for disease identification and choosing the best treatment regimen. According to the Global Cancer Observatory, approximately two million people are diagnosed with colorectal cancer each year, and an accurate diagnosis requires a significant amount of time and a highly qualified pathologist to decrease the high mortality rate. Recent development of artificial intelligence technologies and scanning microscopy introduced digital pathology into the field of cancer diagnosis by means of the whole-slide image (WSI). In this work, we applied deep learning methods to diagnose six types of colon mucosal lesions using convolutional neural networks (CNNs). As a result, an algorithm for the automatic segmentation of WSIs of colon biopsies was developed, implementing pre-trained, deep convolutional neural networks of the ResNet and EfficientNet architectures. We compared the classical method and one-cycle policy for CNN training and applied both multi-class and multi-label approaches to solve the classification problem. The multi-label approach was superior because some WSI patches may belong to several classes at once or to none of them. Using the standard one-vs-rest approach, we trained multiple binary classifiers. They achieved the receiver operator curve AUC in the range of 0.80–0.96. Other metrics were also calculated, such as accuracy, precision, sensitivity, specificity, negative predictive value, and F1-score. Obtained CNNs can support human pathologists in the diagnostic process and can be extended to other cancers after adding a sufficient amount of labeled data.
- Published
- 2022
- Full Text
- View/download PDF
9. In Situ X-ray Absorption Spectroscopy Cells for High Pressure Homogeneous Catalysis
- Author
-
Petr V. Shvets, Pavel A. Prokopovich, Artur I. Dolgoborodov, Oleg A. Usoltsev, Alina A. Skorynina, Elizaveta G. Kozyr, Viktor V. Shapovalov, Alexander A. Guda, Aram L. Bugaev, Evgeny R. Naranov, Dmitry N. Gorbunov, Kwinten Janssens, Dirk E. De Vos, Alexander L. Trigub, Emiliano Fonda, Mark B. Leshchinsky, Vladimir R. Zagackij, Alexander V. Soldatov, and Alexander Yu. Goikhman
- Subjects
operando cell ,X-ray absorption spectroscopy ,XANES ,in situ measurements ,homogeneous catalysis ,heterogeneous catalysis ,Chemical technology ,TP1-1185 ,Chemistry ,QD1-999 - Abstract
We have designed, built, and tested two cells for in situ and, potentially, operando X-ray absorption spectroscopy experiments in transmission and fluorescence modes. The cells were developed for high-pressure and high-temperature conditions to study the catalytic processes under relevant industrial conditions. Operation of the cells was tested for Ru and Rh-based homogeneous and heterogeneous catalytic systems. Using synchrotron-based in situ X-ray absorption spectroscopy we tracked the evolution of active metal species during catalytic reactions. Our setup proved that it was capable to investigate liquid-state homogeneous and heterogenous systems under elevated temperatures, high pressures of reactive gasses, and in the presence of corrosive reagents.
- Published
- 2022
- Full Text
- View/download PDF
10. Narrow-gap, semiconducting, superhard amorphous carbon with high toughness, derived from C60 fullerene
- Author
-
Shuangshuang Zhang, Yingju Wu, Kun Luo, Bing Liu, Yu Shu, Yang Zhang, Lei Sun, Yufei Gao, Mengdong Ma, Zihe Li, Baozhong Li, Pan Ying, Zhisheng Zhao, Wentao Hu, Vicente Benavides, Olga P. Chernogorova, Alexander V. Soldatov, Julong He, Dongli Yu, Bo Xu, and Yongjun Tian
- Subjects
amorphous carbon ,semiconductor ,fullerene ,high pressure and high temperature ,superhard material ,Physics ,QC1-999 - Abstract
Summary: New carbon forms that exhibit extraordinary physicochemical properties can be generated from nanostructured precursors under extreme pressure. Nevertheless, synthesis of such fascinating materials is often not well understood. That is the case of the C60 precursor, with irreproducible results that impede further progress in the materials design. Here, the semiconducting amorphous carbon, having band gaps of 0.1–0.3 eV and the advantages of isotropic superhardness and superior toughness over single-crystal diamond and inorganic glasses, is produced from fullerene at high pressure and moderate temperatures. A systematic investigation of the structure and bonding evolution is carried out with complementary characterization methods, which helps to build a model of the transformation that can be used in further high-pressure/high-temperature (high p,T) synthesis of novel nano-carbon systems for advanced applications. The amorphous carbon materials produced have the potential of accomplishing the demanding optoelectronic applications that diamond and graphene cannot achieve.
- Published
- 2021
- Full Text
- View/download PDF
11. Structural, Electronic, Reactivity, and Conformational Features of 2,5,5-Trimethyl-1,3,2-diheterophosphinane-2-sulfide, and Its Derivatives: DFT, MEP, and NBO Calculations
- Author
-
Nasrin Masnabadi, Mohammad R. Thalji, Huda S. Alhasan, Zahra Mahmoodi, Alexander V. Soldatov, and Gomaa A. M. Ali
- Subjects
natural bond orbitals ,density functional theory ,density of states ,stereoelectronic interactions ,generalized anomeric effect ,Organic chemistry ,QD241-441 - Abstract
In this study, we used density functional theory (DFT) and natural bond orbital (NBO) analysis to determine the structural, electronic, reactivity, and conformational features of 2,5,5-trimethyl-1,3,2-di-heteroatom (X) phosphinane-2-sulfide derivatives (X = O (compound 1), S (compound 2), and Se (compound 3)). We discovered that the features improve dramatically at 6-31G** and B3LYP/6-311+G** levels. The level of theory for the molecular structure was optimized first, followed by the frontier molecular orbital theory development to assess molecular stability and reactivity. Molecular orbital calculations, such as the HOMO–LUMO energy gap and the mapping of molecular electrostatic potential surfaces (MEP), were performed similarly to DFT calculations. In addition, the electrostatic potential of the molecule was used to map the electron density on a surface. In addition to revealing molecules’ size and shape distribution, this study also shows the sites on the surface where molecules are most chemically reactive.
- Published
- 2022
- Full Text
- View/download PDF
12. The Role of Cations and Anions in the Formation of Crystallization Oligomers in Protein Solutions as Revealed by Combination of Small-Angle X-ray Scattering and Molecular Dynamics
- Author
-
Margarita A. Marchenkova, Petr V. Konarev, Yuliya V. Kordonskaya, Kseniia B. Ilina, Yury V. Pisarevsky, Alexander V. Soldatov, Vladimir I. Timofeev, and Mikhail V. Kovalchuk
- Subjects
protein crystallography ,small-angle X-ray scattering ,molecular dynamics simulation ,precipitant ions ,lysozyme oligomers ,protein crystallization ,Crystallography ,QD901-999 - Abstract
As is known from molecular dynamics simulation, lysozyme oligomers in crystallization solutions are most stable when taking into account as many precipitant ions as possible embedded in the corresponding crystal structure. Therefore, the number of precipitant ions associated with crystallographic oligomer models can play a role during the modeling of small-angle X-ray scattering (SAXS) data. This hypothesis has been tested in the present work. As a result, it turned out that the best fit quality to the experimental SAXS data is reached when using oligomers without precipitant ions at all or with embedded chlorine ions. Molecular dynamics (MD) simulation shows that the stability of crystallization oligomers depends on the consideration of anions and cations in oligomer structure. Thus, it is chlorine ions which stabilize dimer and octamers in lysozyme crystallization solution. As SAXS is more sensitive to the role of cations and MD shows the role of anions which are “light” for X-rays, it has been shown that precipitant cations most likely do not bind to monomers, but to already-formed oligomers.
- Published
- 2022
- Full Text
- View/download PDF
13. Accurate control of the covalent functionalization of single-walled carbon nanotubes for the electro-enzymatically controlled oxidation of biomolecules
- Author
-
Naoual Allali, Veronika Urbanova, Mathieu Etienne, Xavier Devaux, Martine Mallet, Brigitte Vigolo, Jean-Joseph Adjizian, Chris P. Ewels, Sven Oberg, Alexander V. Soldatov, Edward McRae, Yves Fort, Manuel Dossot, and Victor Mamane
- Subjects
biosensing ,carbon nanotubes ,covalent functionalization ,electrocatalysis ,ferrocene ,Technology ,Chemical technology ,TP1-1185 ,Science ,Physics ,QC1-999 - Abstract
Single-walled carbon nanotubes (SWCNTs) were functionalized by ferrocene through ethyleneglycol chains of different lengths (FcETGn) and the functionalized SWCNTs (f-SWCNTs) were characterized by different complementary analytical techniques. In particular, high-resolution scanning electron transmission microscopy (HRSTEM) and electron energy loss spectroscopy (EELS) analyses support that the outer tubes of the carbon-nanotube bundles were covalently grafted with FcETGn groups. This result confirms that the electrocatalytic effect observed during the oxidation of the reduced form of nicotinamide adenine dinucleotide (NADH) co-factor by the f-SWCNTs is due to the presence of grafted ferrocene derivatives playing the role of a mediator. This work clearly proves that residual impurities present in our SWCNT sample (below 5 wt. %) play no role in the electrocatalytic oxidation of NADH. Moreover, molecular dynamic simulations confirm the essential role of the PEG linker in the efficiency of the bioelectrochemical device in water, due to the favorable interaction between the ETG units and water molecules that prevents π-stacking of the ferrocene unit on the surface of the CNTs. This system can be applied to biosensing, as exemplified for glucose detection. The well-controlled and well-characterized functionalization of essentially clean SWCNTs enabled us to establish the maximum level of impurity content, below which the f-SWCNT intrinsic electrochemical activity is not jeopardized.
- Published
- 2018
- Full Text
- View/download PDF
14. Operando Photo-Electrochemical Catalysts Synchrotron Studies
- Author
-
Mikhail A. Soldatov, Pavel V. Medvedev, Victor Roldugin, Ivan N. Novomlinskiy, Ilia Pankin, Hui Su, Qinghua Liu, and Alexander V. Soldatov
- Subjects
photo-electrochemistry ,PEC cells ,synchrotron ,XANES ,operando ,CO2 reduction ,Chemistry ,QD1-999 - Abstract
The attempts to develop efficient methods of solar energy conversion into chemical fuel are ongoing amid climate changes associated with global warming. Photo-electrocatalytic (PEC) water splitting and CO2 reduction reactions show high potential to tackle this challenge. However, the development of economically feasible solutions of PEC solar energy conversion requires novel efficient and stable earth-abundant nanostructured materials. The latter are hardly available without detailed understanding of the local atomic and electronic structure dynamics and mechanisms of the processes occurring during chemical reactions on the catalyst–electrolyte interface. This review considers recent efforts to study photo-electrocatalytic reactions using in situ and operando synchrotron spectroscopies. Particular attention is paid to the operando reaction mechanisms, which were established using X-ray Absorption (XAS) and X-ray Photoelectron (XPS) Spectroscopies. Operando cells that are needed to perform such experiments on synchrotron are covered. Classical and modern theoretical approaches to extract structural information from X-ray Absorption Near-Edge Structure (XANES) spectra are discussed.
- Published
- 2022
- Full Text
- View/download PDF
15. Synthesis, Characterization and Biodistribution of GdF3:Tb3+@RB Nanocomposites
- Author
-
Oleg E. Polozhentsev, Ilia A. Pankin, Darya V. Khodakova, Pavel V. Medvedev, Anna S. Goncharova, Aleksey Yu. Maksimov, Oleg I. Kit, and Alexander V. Soldatov
- Subjects
scintillating nanoparticle ,GdF3:Tb3+ ,organic photosensitizer ,Rose Bengal ,X-ray induced photodynamic therapy ,computer tomography ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
Herein we report the development of a nanocomposite for X-ray-induced photodynamic therapy (X-PDT) and computed tomography (CT) based on PEG-capped GdF3:Tb3+ scintillating nanoparticles conjugated with Rose Bengal photosensitizer via electrostatic interactions. Scintillating GdF3:Tb3+ nanoparticles were synthesized by a facile and cost-effective wet chemical precipitation method. All synthesized nanoparticles had an elongated “spindle-like” clustered morphology with an orthorhombic structure. The structure, particle size, and morphology were determined by transmission electron microscopy (TEM), X-ray diffraction (XRD), and dynamic light scattering (DLS) analysis. The presence of a polyethylene glycol (PEG) coating and Rose Bengal conjugates was proved by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and ultraviolet–visible (UV-vis) analysis. Upon X-ray irradiation of the colloidal PEG-capped GdF3:Tb3+–Rose Bengal nanocomposite solution, an efficient fluorescent resonant energy transfer between scintillating nanoparticles and Rose Bengal was detected. The biodistribution of the synthesized nanoparticles in mice after intravenous administration was studied by in vivo CT imaging.
- Published
- 2022
- Full Text
- View/download PDF
16. Data-Centric Architecture for Self-Driving Laboratories with Autonomous Discovery of New Nanomaterials
- Author
-
Maria A. Butakova, Andrey V. Chernov, Oleg O. Kartashov, and Alexander V. Soldatov
- Subjects
data-centric architecture ,data flow model ,self-driving laboratory ,autonomous nanomaterials discovery ,Chemistry ,QD1-999 - Abstract
Artificial intelligence (AI) approaches continue to spread in almost every research and technology branch. However, a simple adaptation of AI methods and algorithms successfully exploited in one area to another field may face unexpected problems. Accelerating the discovery of new functional materials in chemical self-driving laboratories has an essential dependence on previous experimenters’ experience. Self-driving laboratories help automate and intellectualize processes involved in discovering nanomaterials with required parameters that are difficult to transfer to AI-driven systems straightforwardly. It is not easy to find a suitable design method for self-driving laboratory implementation. In this case, the most appropriate way to implement is by creating and customizing a specific adaptive digital-centric automated laboratory with a data fusion approach that can reproduce a real experimenter’s behavior. This paper analyzes the workflow of autonomous experimentation in the self-driving laboratory and distinguishes the core structure of such a laboratory, including sensing technologies. We propose a novel data-centric research strategy and multilevel data flow architecture for self-driving laboratories with the autonomous discovery of new functional nanomaterials.
- Published
- 2021
- Full Text
- View/download PDF
17. Photoswitchable Zirconium MOF for Light-Driven Hydrogen Storage
- Author
-
Vera V. Butova, Olga A. Burachevskaya, Vitaly A. Podshibyakin, Evgenii N. Shepelenko, Andrei A. Tereshchenko, Svetlana O. Shapovalova, Oleg I. Il’in, Vladimir A. Bren’, and Alexander V. Soldatov
- Subjects
UiO-66 ,smart material ,diarylethene ,UiO-66-NH2 ,photochromism ,activation ,Organic chemistry ,QD241-441 - Abstract
Here, we report a new photosensitive metal–organic framework (MOF) that was constructed via the modification of UiO-66-NH2 with diarylethene molecules (DAE, 4-(5-Methoxy-1,2-dimethyl-1H-indol-3-yl)-3-(2,5-dimethylthiophen-3-yl)-4-furan-2,5-dione). The material that was obtained was a highly crystalline porous compound. The photoresponse of the modified MOF was observed via UV–Vis and IR spectroscopy. Most of the DAE molecules inside of the UiO-66-pores had an open conformation after synthesis. However, the equilibrium was able to be shifted further toward an open conformation using visible light irradiation with a wavelength of 520 nm. Conversely, UV-light with a wavelength of 450 nm initiated the transformation of the photoresponsive moieties inside of the pores to a closed modification. We have shown that this transformation could be used to stimulate hydrogen adsorption–desorption processes. Specifically, visible light irradiation increased the H2 capacity of modified MOF, while UV-light decreased it. A similar hybrid material with DAE moieties in the UiO-66 scaffold was applied for hydrogen storage for the first time. Additionally, the obtained results are promising for smart H2 storage that is able to be managed via light stimuli.
- Published
- 2021
- Full Text
- View/download PDF
18. The Recent Progress on Silver Nanoparticles: Synthesis and Electronic Applications
- Author
-
Abderrhmane Bouafia, Salah Eddine Laouini, Abdelaal S. A. Ahmed, Alexander V. Soldatov, Hamed Algarni, Kwok Feng Chong, and Gomaa A. M. Ali
- Subjects
silver nanoparticles ,green synthesis ,electronic applications ,solar cells ,gas sensors ,Chemistry ,QD1-999 - Abstract
Nanoscience enables researchers to develop new and cost-effective nanomaterials for energy, healthcare, and medical applications. Silver nanoparticles (Ag NPs) are currently increasingly synthesized for their superior physicochemical and electronic properties. Good knowledge of these characteristics allows the development of applications in all sensitive and essential fields in the service of humans and the environment. This review aims to summarize the Ag NPs synthesis methods, properties, applications, and future challenges. Generally, Ag NPs can be synthesized using physical, chemical, and biological routes. Due to the great and increasing demand for metal and metal oxide nanoparticles, researchers have invented a new, environmentally friendly, inexpensive synthetic method that replaces other methods with many defects. Studies of Ag NPs have increased after clear and substantial support from governments to develop nanotechnology. Ag NPs are the most widely due to their various potent properties. Thus, this comprehensive review discusses the different synthesis procedures and electronic applications of Ag NPs.
- Published
- 2021
- Full Text
- View/download PDF
19. Green Synthesized of Ag/Ag2O Nanoparticles Using Aqueous Leaves Extracts of Phoenix dactylifera L. and Their Azo Dye Photodegradation
- Author
-
Salah Eddine Laouini, Abderrhmane Bouafia, Alexander V. Soldatov, Hamed Algarni, Mohammed Laid Tedjani, Gomaa A. M. Ali, and Ahmed Barhoum
- Subjects
silver/silver oxide nanoparticles ,Phoenix dactylifera L. ,photosynthesis ,catalytic activity ,dye degradation ,Chemical technology ,TP1-1185 ,Chemical engineering ,TP155-156 - Abstract
In this study, silver/silver oxide nanoparticles (Ag/Ag2O NPs) were successfully biosynthesized using Phoenix dactylifera L. aqueous leaves extract. The effect of different plant extract/precursor contractions (volume ratio, v/v%) on Ag/Ag2O NP formation, their optical properties, and photocatalytic activity towards azo dye degradation, i.e., Congo red (CR) and methylene blue (MB), were investigated. X-ray diffraction confirmed the crystalline nature of Ag/Ag2O NPs with a crystallite size range from 28 to 39 nm. Scanning electron microscope images showed that the Ag/Ag2O NPs have an oval and spherical shape. UV–vis spectroscopy showed that Ag/Ag2O NPs have a direct bandgap of 2.07–2.86 eV and an indirect bandgap of 1.60–1.76 eV. Fourier transform infrared analysis suggests that the synthesized Ag/Ag2O NPs might be stabilized through the interactions of -OH and C=O groups in the carbohydrates, flavonoids, tannins, and phenolic acids present in Phoenix dactylifera L. Interestingly, the prepared Ag/Ag2O NPs showed high catalytic degradation activity for CR dye. The photocatalytic degradation of the azo dye was monitored spectrophotometrically in a wavelength range of 250–900 nm, and a high decolorization efficiency (84.50%) was obtained after 50 min of reaction. As a result, the use of Phoenix dactylifera L. aqueous leaves extract offers a cost-effective and eco-friendly method.
- Published
- 2021
- Full Text
- View/download PDF
20. Individual expression features of GPX2, NQO1 and SQSTM1 transcript variants induced by hydrogen peroxide treatment in HeLa cells
- Author
-
Anna A. Belanova, Dmitry S. Smirnov, Maxim S. Makarenko, Mariya M. Belousova, Elena V. Mashkina, Anzhela A. Aleksandrova, Alexander V. Soldatov, and Peter V. Zolotukhin
- Subjects
NFE2L2/AP-1 pathway ,interactomics ,transcript variants expression control ,Genetics ,QH426-470 - Abstract
Abstract Pathway activity assessment-based approaches are becoming highly influential in various fields of biology and medicine. However, these approaches mostly rely on analysis of mRNA expression, and total mRNA from a given locus is measured in the majority of cases. Notably, a significant portion of protein-coding genes produces more than one transcript. This biological fact is responsible for significant noise when changes in total mRNA transcription of a single gene are analyzed. The NFE2L2/AP-1 pathway is an attractive target for biomedical applications. To date, there is a lack of data regarding the agreement in expression of even classical target genes of this pathway. In the present paper we analyzed whether transcript variants of GPX2, NQO1 and SQSTM1 were characterized by individual features of expression when HeLa cells were exposed to pro-oxidative stimulation with hydrogen peroxide. We found that all the transcripts (10 in total) appeared to be significantly individually regulated under the conditions tested. We conclude that individual transcripts, rather than total mRNA, are best markers of pathway activation. We also discuss here some biological roles of individual transcript regulation.
- Published
- 2017
- Full Text
- View/download PDF
21. MEGA-SCIENCE FACILITIES AS AN IMPORTANT INSTRUMENT FOR SYNERGY OF WORLD LEVEL EDUCATION AND SCIENCE
- Author
-
Alexander V. Soldatov
- Subjects
научная деятельность университетов ,установки мега-класса ,mega-science ,интеграция науки и образования ,university research activities ,mega-scale research facilities ,“mega-science” ,research and education synergy ,integration of science and education ,Education - Abstract
The paper discusses the prospects for connecting the universities to use Mega- Science research facilities as an important tool for the integration of world level science and education. The need for such integration of leading universities with research organizations was noted in the RF Government Decision of 19 June 2015 on the results of the joint meeting of the boards of trustees of the Southern and Siberian Federal University.
- Published
- 2016
22. In situ X-ray absorption spectroscopy data during formation of active Pt- and Pd-sites in functionalized UiO-67 metal-organic frameworks
- Author
-
Aram L. Bugaev, Alina A. Skorynina, Elizaveta G. Kamyshova, Kirill A. Lomachenko, Alexander A. Guda, Alexander V. Soldatov, and Carlo Lamberti
- Subjects
Computer applications to medicine. Medical informatics ,R858-859.7 ,Science (General) ,Q1-390 - Abstract
We report a series of Pd K-edge and Pt L3-edge X-ray absorption spectra (XAS) collected in situ during thermal treatment of functionalized UiO-67-Pd and UiO-67-Pt metal-organic frameworks in inert and reducing atmospheres. We present raw synchrotron data from three subsequent experiments at different beamlines, normalized XAS spectra and k2-weighted oscillatory χ(k) functions extracted from one of the datasets. Pd K-edge spectra were collected for the samples in 5% H2/He, 3% H2/He and pure He in the temperature range from room temperature (RT) to 450 °C. Pt L3-edge were collected for the samples in 3% H2/He, 10% H2/He and pure He in the temperature range from RT to 300 °C. All spectra are reported together with the used atmosphere and temperature. For the analysis of all reported datasets, please see “Evolution of Pt and Pd species in functionalized UiO-67 metal-organic frameworks”. Fourier-analysis of Pd K-edge is reported in “Formation and growth of Pd nanoparticles in UiO-67 MOF by in situ EXAFS”. Keywords: EXAFS, XANES, MOFs, Nanoparticles
- Published
- 2019
- Full Text
- View/download PDF
23. Operando X-ray absorption spectra and mass spectrometry data during hydrogenation of ethylene over palladium nanoparticles
- Author
-
Aram L. Bugaev, Alexander A. Guda, Ilia A. Pankin, Elena Groppo, Riccardo Pellegrini, Alessandro Longo, Alexander V. Soldatov, and Carlo Lamberti
- Subjects
Computer applications to medicine. Medical informatics ,R858-859.7 ,Science (General) ,Q1-390 - Abstract
We report the series of Pd K-edge X-ray absorption spectra collected during hydrogenation of ethylene with variable ethylene/hydrogen ratio over carbon supported palladium nanoparticles. The data presented in this article includes normalized X-ray absorption spectra, k2-weighted oscillatory χ(k) functions extracted from the extended X-ray absorption fine structure (EXAFS) and k2-weighted Fourier-transformed EXAFS data, χ(R). Each spectrum is reported together with the hydrogen, ethylene and helium flow rates, adjusted during its collection. In addition, time evolution of the ratio of m/Z signals of 30 and 28 registered by online mass spectrometer is presented. The data analysis is reported in Bugaev et al., Catal. Today, 2019 [1].
- Published
- 2019
- Full Text
- View/download PDF
24. Self-Driving Laboratories for Development of New Functional Materials and Optimizing Known Reactions
- Author
-
Mikhail A. Soldatov, Vera V. Butova, Danil Pashkov, Maria A. Butakova, Pavel V. Medvedev, Andrey V. Chernov, and Alexander V. Soldatov
- Subjects
self-driving laboratories ,artificial intelligence ,synthesis ,automatization ,optimization ,Chemistry ,QD1-999 - Abstract
Innovations often play an essential role in the acceleration of the new functional materials discovery. The success and applicability of the synthesis results with new chemical compounds and materials largely depend on the previous experience of the researcher himself and the modernity of the equipment used in the laboratory. Artificial intelligence (AI) technologies are the next step in developing the solution for practical problems in science, including the development of new materials. Those technologies go broadly beyond the borders of a computer science branch and give new insights and practical possibilities within the far areas of expertise and chemistry applications. One of the attractive challenges is an automated new functional material synthesis driven by AI. However, while having many years of hands-on experience, chemistry specialists have a vague picture of AI. To strengthen and underline AI’s role in materials discovery, a short introduction is given to the essential technologies, and the machine learning process is explained. After this review, this review summarizes the recent studies of new strategies that help automate and accelerate the development of new functional materials. Moreover, automatized laboratories’ self-driving cycle could benefit from using AI algorithms to optimize new functional nanomaterials’ synthetic routes. Despite the fact that such technologies will shape material science in the nearest future, we note the intelligent use of algorithms and automation is required for novel discoveries.
- Published
- 2021
- Full Text
- View/download PDF
25. ᶫ-Leucine Loading and Release in MIL-100 Nanoparticles
- Author
-
Ivan E. Gorban, Mikhail A. Soldatov, Vera V. Butova, Pavel V. Medvedev, Olga A. Burachevskaya, Anna Belanova, Peter Zolotukhin, and Alexander V. Soldatov
- Subjects
MOF nanoparticles ,MIL-100 ,targeted drug delivery ,leucine ,nanomedicine ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Synthesis of the MIL-100 metal-organic framework particles was carried out by hydrothermal (HT) and microwave (MW)-assisted methods. Transmission electron microscopy showed formation of microparticles in the course of hydrothermal synthesis and nanoparticles for microwave-assisted synthesis. Powder X-ray diffraction confirmed formation of larger crystallites for hydrothermal synthesis. Particle aggregation in aqueous solution was observed by dynamic light scattering. However, the stability of both samples could be improved in acetic acid solution. Nitrogen sorption isotherms showed high porosity of the particles. ᶫ-leucine molecule was used as a model molecule for loading in the porous micro- and nanoparticles. Loading was estimated by FTIR spectroscopy and thermogravimetric analysis. UV-VIS spectroscopy quantified ᶫ-leucine release from the particles in aqueous solution. Cytotoxicity studies using the HeLa cell model showed that the original particles were somewhat toxic, but ᶫ-leucine loading ameliorated the toxic effects, likely due to signaling properties of the amino acid.
- Published
- 2020
- Full Text
- View/download PDF
26. MW Synthesis of ZIF-7. The Effect of Solvent on Particle Size and Hydrogen Sorption Properties
- Author
-
Vladimir A. Polyakov, Vera V. Butova, Elena A. Erofeeva, Andrei A. Tereshchenko, and Alexander V. Soldatov
- Subjects
ZIF-7 ,hydrogen storage ,microwave synthesis ,Technology - Abstract
We report here fast (15 min) microwave-assisted solvothermal synthesis of zeolitic imidazolate framework material (ZIF-7). We have optimized solvent composition to achieve high porosity and hydrogen capacity and narrow particle size distribution. It was shown that synthesis in N,N-diethylformamide (DEF) results in a layered ZIF-7 III phase, while N,N-dimethylformamide (DMF) as solvent leads to a pure ZIF-7 phase in microwave conditions. A mixture of toluene with DMF allows the production of pure ZIF-7 material only with the triethylamine additive. Obtained materials were comprehensively characterized. We have pointed out that both X-ray diffraction and infrared spectroscopy could be used for the identification of ZIF-7 or ZIF-7 III phases. Although samples obtained in DMF, and in a mixture of DMF, toluene, and triethylamine were assigned to the pure ZIF-7 phase, solvent composition significantly affected the size of particles in the material and nitrogen and hydrogen adsorption process.
- Published
- 2020
- Full Text
- View/download PDF
27. Dehydrogenation of Ethylene on Supported Palladium Nanoparticles: A Double View from Metal and Hydrocarbon Sides
- Author
-
Oleg A. Usoltsev, Anna Yu. Pnevskaya, Elizaveta G. Kamyshova, Andrei A. Tereshchenko, Alina A. Skorynina, Wei Zhang, Tao Yao, Aram L. Bugaev, and Alexander V. Soldatov
- Subjects
palladium nanoparticles ,ethylene dehydrogenation ,XANES ,EXAFS ,DRIFTS ,DFT ,Chemistry ,QD1-999 - Abstract
Adsorption of ethylene on palladium, a key step in various catalytic reactions, may result in a variety of surface-adsorbed species and formation of palladium carbides, especially under industrially relevant pressures and temperatures. Therefore, the application of both surface and bulk sensitive techniques under reaction conditions is important for a comprehensive understanding of ethylene interaction with Pd-catalyst. In this work, we apply in situ X-ray absorption spectroscopy, X-ray diffraction and infrared spectroscopy to follow the evolution of the bulk and surface structure of an industrial catalysts consisting of 2.6 nm supported palladium nanoparticles upon exposure to ethylene under atmospheric pressure at 50 °C. Experimental results were complemented by ab initio simulations of atomic structure, X-ray absorption spectra and vibrational spectra. The adsorbed ethylene was shown to dehydrogenate to C2H3, C2H2 and C2H species, and to finally decompose to palladium carbide. Thus, this study reveals the evolution pathway of ethylene on industrial Pd-catalyst under atmospheric pressure at moderate temperatures, and provides a conceptual framework for the experimental and theoretical investigation of palladium-based systems, in which both surface and bulk structures exhibit a dynamic nature under reaction conditions.
- Published
- 2020
- Full Text
- View/download PDF
28. Synthesis of ZnO Nanoparticles Doped with Cobalt Using Bimetallic ZIFs as Sacrificial Agents
- Author
-
Vera V. Butova, Vladimir A. Polyakov, Elena A. Erofeeva, Sofia A. Efimova, Mikhail A. Soldatov, Alexander L. Trigub, Yury V. Rusalev, and Alexander V. Soldatov
- Subjects
ZIF-8 ,ZIF-67 ,bimetallic ,zinc oxide ,cobalt doping ,pyrolysis ,Chemistry ,QD1-999 - Abstract
We report here a simple two-stage synthesis of zinc–cobalt oxide nanoparticles. We used Zn/Co-zeolite imidazolate framework (ZIF)-8 materials as precursors for annealing and optional impregnation with a silicon source for the formation of a protective layer on the surface of oxide nanoparticles. Using bimetallic ZIFs allowed us to trace the phase transition of the obtained oxide nanoparticles from wurtzite ZnO to spinel Co3O4 structures. Using (X-ray diffraction) XRD and (X-ray Absorption Near Edge Structure) XANES techniques, we confirmed the incorporation of cobalt ions into the ZnO structure up to 5 mol.% of Co. Simple annealing of Zn/Co-ZIF-8 materials in the air led to the formation of oxide nanoparticles of about 20–30 nm, while additional treatment of ZIFs with silicon source resulted in nanoparticles of about 5–10 nm covered with protective silica layer. We revealed the incorporation of oxygen vacancies in the obtained ZnO nanoparticles using FTIR analysis. All obtained samples were comprehensively characterized, including analysis with a synchrotron radiation source.
- Published
- 2020
- Full Text
- View/download PDF
29. In Situ Time-Resolved Decomposition of β-Hydride Phase in Palladium Nanoparticles Coated with Metal-Organic Framework
- Author
-
Mikhail V. Kirichkov, Aram L. Bugaev, Alina A. Skorynina, Vera V. Butova, Andriy P. Budnyk, Alexander A. Guda, Alexander L. Trigub, and Alexander V. Soldatov
- Subjects
palladium nanoparticles ,palladium hydrides ,metal-organic frameworks ,x-ray diffraction ,Mining engineering. Metallurgy ,TN1-997 - Abstract
The formation of palladium hydrides is a well-known phenomenon, observed for both bulk and nanosized samples. The kinetics of hydrogen adsorption/desorption strongly depends on the particle size and shape, as well as the type of support and/or coating of the particles. In addition, the structural properties of hydride phases and their distribution also depend on the particle size. In this work, we report on the in situ characterization of palladium nanocubes coated with HKUST-1 metal-organic framework (Pd@HKUST-1) during desorption of hydrogen by means of synchrotron-based time-resolved X-ray powder diffraction. A slower hydrogen desorption, compared to smaller sized Pd nanoparticles was observed. Rietveld refinement of the time-resolved data revealed the remarkable stability of the lattice parameters of α- and β-hydride phases of palladium during the α- to β- phase transition, denoting the behavior more similar to the bulk materials than nanoparticles. The stability in the crystal sizes for both α- and β-hydride phases during the phase transition indicates that no sub-domains are formed within a single particle during the phase transition.
- Published
- 2020
- Full Text
- View/download PDF
30. Chemical Synthesis and Characterization of Pd/SiO2: The Effect of Chemical Reagent
- Author
-
Aram L. Bugaev, Vladimir A. Polyakov, Andrei A. Tereshchenko, Ashura N. Isaeva, Alina A. Skorynina, Elizaveta G. Kamyshova, Andriy P. Budnyk, Tatiana A. Lastovina, and Alexander V. Soldatov
- Subjects
palladium nanoparticles ,hydrazine ,wet-synthesis ,solvothermal polyol synthesis ,Mining engineering. Metallurgy ,TN1-997 - Abstract
The size and shape distribution of metal nanoparticles (NPs) are important parameters that need to be tuned in order to achieve desired properties of materials for practical applications. In the current work, we present the synthesis of palladium NPs supported on silica by three different methods, applying reduction by sodium borohydride, hydrazine vapors, and polyethylene glycol (PEG). The synthesized materials were characterized by X-ray diffraction, X-ray fluorescence, transmission electron microscopy, surface area and porosity measurements, and thermogravimetric analysis. Similar nanoparticle sizes with narrow size distribution centered at 8 nm were obtained after reduction by sodium borohydride and hydrazine vapors, whereas the smallest particle size of about 4.8 nm was obtained after reduction by PEG. The effect of modification of the initial palladium chloride compound by ammonium hydroxide was found to lead to the formation of larger particles with average size of 15 nm and broader size distribution. In addition, the process of the reduction of palladium by PEG at different reduction stages was monitored by UV-Vis spectroscopy. CO-stripping voltammetry showed that reduction in hydrazine and in PEG allowed the preparation of Pd NPs with high electrochemically-active surface area. Such NPs are promising materials for electrocatalysis.
- Published
- 2018
- Full Text
- View/download PDF
31. Machine Learning Analysis of Reaction Parameters in UV-Mediated Synthesis of Gold Nanoparticles
- Author
-
Alexander A. Guda, Mikhail V. Kirichkov, Viktor V. Shapovalov, Alexey I. Muravlev, Danil M. Pashkov, Sergey A. Guda, Anton P. Bagliy, Sergey A. Soldatov, Sergey V. Chapek, and Alexander V. Soldatov
- Subjects
General Energy ,Physical and Theoretical Chemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2023
32. One-step electrochemical synthesis of γ-Fe2O3@MIL-88a magnetic composite for heterogeneous Fenton-like catalysis
- Author
-
Andrey A. Kuzharov, Maksim A. Gritsai, Vera V. Butova, Mikhail A. Soldatov, Vladimir A. Polyakov, Polina A. Rud, Yury V. Rusalev, Stanislav P. Kubrin, Victor A. Roldugin, Alexander L. Trigub, and Alexander V. Soldatov
- Subjects
Process Chemistry and Technology ,Materials Chemistry ,Ceramics and Composites ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2022
33. Effect of a stabilizer on the structure, synthesis, and tribological properties of silver nanoparticles
- Author
-
Andrey A. Kuzharov, Aleksey A. Milov, Julia S. Gerasina, Mikhail A. Soldatov, Vera V. Butova, and Alexander V. Soldatov
- Subjects
Mechanical Engineering ,Surfaces and Interfaces ,Surfaces, Coatings and Films - Abstract
The structure and properties of nanoparticles are greatly influenced by the synthesis method and the stabilizer used in their preparation. The paper presents the results of the effect of various stabilizers (gelatin, sodium citrate, sodium borohydride) on the structure, synthesis, and tribotechnical properties of silver nanoparticles. The mechanism of the formation and growth of silver nanoclusters was investigated using quantum-chemical calculations with full optimization of all parameters using the density functional theory (DFT) PBEPBE/Lanl2DZ method. It is shown that the use of organic stabilizers (for example, gelatin) leads to an increase in the stability of stabilized silver clusters. Such systems have greater conformational flexibility and a large number of molecular donor oxygen centres in their composition. The effect of the stabilizer on the structure of the Ag13 silver cluster was revealed in four model systems: gelatin, ammonium chloride NH4Cl, sodium borohydride NaBH4, and trisodium citrate Na3C6H5O (Na3Cit). Silver nanoparticles (AgNPs) obtained by the sonoelectrochemical, citrate, borohydride, and citrate-borohydride method varied in size from nanometers to several tens of nanometers. As a result of tribotechnical tests of lubricants with the obtained silver nanoparticles, a positive effect of stabilized silver clusters was revealed in the composition of lubricant compositions. The best tribotechnical characteristics were shown by lubricating compositions containing AgNPs stabilized with gelatin. It was found that a decrease in the size of gelatin stabilized AgNPs, when added to lubricants, leads to an increase in the tribological properties.
- Published
- 2022
34. 3D Printed Microfluidic Cell for SAXS Time-Resolved Measurements of the Structure of Protein Crystallization Solutions
- Author
-
Kovalchuk, Margarita A. Marchenkova, Sergei V. Chapek, Petr V. Konarev, Ksenia B. Ilina, Georgy S. Peters, Yury V. Pisarevsky, Vladimir A. Shishkov, Alexander V. Soldatov, and Mikhail V.
- Subjects
synchrotron radiation ,small-angle X-ray scattering ,sample cell ,structure of solutions ,lysozyme ,3D printing - Abstract
A multichannel microfluidic cell (MFC) obtained using 3D printing for studying the structure of complex solutions by small-angle X-ray scattering (SAXS) is described. MFC was tested at the BioMUR beamline of the Kurchatov synchrotron. A comparative analysis of SAXS signal from the standard capillary and from the developed MFC was carried out, with MFC showing significant advantages. The dynamics of SAXS scattering curves for lysozyme solutions with NaCl precipitant were studied when the protein and precipitant concentrations changed. The obtained time series of data are well consistent with the known data for the lysozyme solution.
- Published
- 2023
- Full Text
- View/download PDF
35. Ultrastrong conductive in situ composite composed of nanodiamond incoherently embedded in disordered multilayer graphene
- Author
-
Zihe Li, Yujia Wang, Mengdong Ma, Huachun Ma, Wentao Hu, Xiang Zhang, Zewen Zhuge, Shuangshuang Zhang, Kun Luo, Yufei Gao, Lei Sun, Alexander V. Soldatov, Yingju Wu, Bing Liu, Baozhong Li, Pan Ying, Yang Zhang, Bo Xu, Julong He, Dongli Yu, Zhongyuan Liu, Zhisheng Zhao, Yuanzheng Yue, Yongjun Tian, and Xiaoyan Li
- Subjects
Mechanics of Materials ,Mechanical Engineering ,General Materials Science ,General Chemistry ,Condensed Matter Physics - Abstract
Traditional ceramics or metals cannot simultaneously achieve ultrahigh strength and high electrical conductivity. The elemental carbon can form a variety of allotropes with entirely different physical properties, providing versatility for tuning mechanical and electrical properties in a wide range. Here, by precisely controlling the extent of transformation of amorphous carbon into diamond within a narrow temperature–pressure range, we synthesize an in situ composite consisting of ultrafine nanodiamond homogeneously dispersed in disordered multilayer graphene with incoherent interfaces, which demonstrates a Knoop hardness of up to ~53 GPa, a compressive strength of up to ~54 GPa and an electrical conductivity of 670–1,240 S m–1 at room temperature. With atomically resolving interface structures and molecular dynamics simulations, we reveal that amorphous carbon transforms into diamond through a nucleation process via a local rearrangement of carbon atoms and diffusion-driven growth, different from the transformation of graphite into diamond. The complex bonding between the diamond-like and graphite-like components greatly improves the mechanical properties of the composite. This superhard, ultrastrong, conductive elemental carbon composite has comprehensive properties that are superior to those of the known conductive ceramics and C/C composites. The intermediate hybridization state at the interfaces also provides insights into the amorphous-to-crystalline phase transition of carbon.
- Published
- 2023
36. How Much Structural Information Could Be Extracted from XANES Spectra for Palladium Hydride and Carbide Nanoparticles
- Author
-
Oleg A. Usoltsev, Aram L. Bugaev, Alexander A. Guda, Sergey A. Guda, and Alexander V. Soldatov
- Subjects
General Energy ,Physical and Theoretical Chemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2022
37. Statistical design of experiments for biocomposite (Zea mays sponge/Na-alginate) preparation optimization for Pb(II) removal from aqueous media
- Author
-
Messaouda Matallah, Hicham Gouzi, Boubakeur Saidat, Hmida Fekirini, Gomaa A.M. Ali, Alexander V. Soldatov, Yasmina Khane, Djilali Boulerba, and Abdelhalim Zoukel
- Published
- 2022
38. PyFitit: The software for quantitative analysis of XANES spectra using machine-learning algorithms.
- Author
-
Andrea Martini, Sergey Guda, Alexander Guda, G. Smolentsev, Alexander Algasov, Oleg Usoltsev, Mikhail A. Soldatov, Aram Bugaev, Yury Rusalev, Carlo Lamberti, and Alexander V. Soldatov
- Published
- 2020
- Full Text
- View/download PDF
39. Complex diagnostics of ordinary chondrites Markovka, Polujamki, Sayh al Uhaymir 001, Dhofar 020, and Jiddat al Harasis 055 by X‐ray techniques and Mössbauer spectroscopy
- Author
-
Liubov V. Guda, Antonina N. Kravtsova, Stanislav P. Kubrin, Alexander A. Guda, Mikhail I. Mazuritskiy, Andrei A. Tereshchenko, Yuri V. Popov, and Alexander V. Soldatov
- Subjects
Geophysics ,Space and Planetary Science - Published
- 2021
40. Revisited Ti2Nb2O9 as an Anode Material for Advanced Li-Ion Batteries
- Author
-
Oleg A. Drozhzhin, Evgeny V. Antipov, O. V. Boytsova, Victor V. Shapovalov, Anastasia M. Alekseeva, Artem M. Abakumov, Ruslan R. Samigullin, Dmitry A. Aksyonov, Alexander A. Guda, Keith J. Stevenson, Alexander V. Soldatov, Vladislav V. Grigoryev, and Dmitry Chernyshov
- Subjects
Materials science ,law ,Thermal decomposition ,Intercalation (chemistry) ,Analytical chemistry ,General Materials Science ,Density functional theory ,Absorption (chemistry) ,XANES ,Synchrotron ,Anode ,Ion ,law.invention - Abstract
Ti2Nb2O9 with a tunnel-type structure is considered as a perspective negative electrode material for Li-ion batteries (LIBs) with theoretical capacity of 252 mAh g-1 corresponding to one-electron reduction/oxidation of Ti and Nb, but only ≈160 mAh g-1 has been observed practically. In this work, highly reversible capacity of 200 mAh g-1 with the average (de)lithiation potential of 1.5 V vs Li/Li+ is achieved for Ti2Nb2O9 with pseudo-2D layered morphology obtained via thermal decomposition of the NH4TiNbO5 intermediate prepared by K+→ H+→ NH4+ cation exchange from KTiNbO5. Using operando synchrotron powder X-ray diffraction (SXPD), single-phase (de)lithiation mechanism with 4.8% unit cell volume change is observed. Operando X-ray absorption near-edge structure (XANES) experiment revealed simultaneous Ti4+/Ti3+ and Nb5+/Nb4+ reduction/oxidation within the whole voltage range. Li+ migration barriers for Ti2Nb2O9 along [010] direction derived from density functional theory (DFT) calculations are within the 0.15-0.4 eV range depending on the Li content that is reflected in excellent C-rate capacity retention. Ti2Nb2O9 synthesized via the ion-exchange route appears as a strong contender to widely commercialized Ti-based negative electrode material Li4Ti5O12 in the next generation of high-performance LIBs.
- Published
- 2021
41. Temperature and Time-resolved XANES Studies of Novel Valence Tautomeric Cobalt Complex
- Author
-
Alexander V. Soldatov, Vladimir K. Cherkasov, Grigory Smolentsev, Yu. V. Rusalev, V. V. Shapovalov, Valery G. Vlasenko, S. O. Shapovalova, Alexey A. Zolotukhin, Andrey G. Starikov, Alexander A. Guda, and M. P. Bubnov
- Subjects
Crystallography ,Valence (chemistry) ,Chemistry ,chemistry.chemical_element ,General Chemistry ,Cobalt ,Tautomer ,XANES - Abstract
VT transition from the high-spin CoII to low-spin CoIII state was observed for complex (N-cyclo-hexyl-2-iminopyridine)(3,6-di-tert-butyl-o-benzosemiquinonato)(3,6-di-tert-butyl-catecholato)cobalt i...
- Published
- 2021
42. Enhancement of the electrochemical performance of LiCoPO4 by Fe doping
- Author
-
Alexander A. Guda, F. Elmasry, A.M. Aboraia, V. V. Shapovalov, Alexander V. Soldatov, and M.G. Moustafa
- Subjects
Materials science ,Absorption spectroscopy ,Annealing (metallurgy) ,Process Chemistry and Technology ,Doping ,Analytical chemistry ,chemistry.chemical_element ,Electrolyte ,Cathode ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry ,law ,Phase (matter) ,Materials Chemistry ,Ceramics and Composites ,Orthorhombic crystal system ,Cobalt - Abstract
LiCoPO4 is an attractive cathode material, but it undergoes poor electronic conductivity and electrochemical performance. This performance is enhanced by substituting iron antisite Cobalt to reduce the direct interaction between the cathode and the electrolyte. Thus, LiCoPO4 doped with Fe was synthesized by the microwave-assisted solvothermal route at 220 °C. According to X-ray diffraction analysis, a single orthorhombic Pn21a phase (a = 10.02 A, b = 6.71 A and c = 4.96 A) was obtained, which transited to Pnma phase (a = 10.21 A b = 5.92 A and c = 4.76 A) after annealing at 700 °C in air. The morphology and particle size of the sample changed after annealing, as shown by TEM. The electrochemical cycling of an annealed sample showed the initial discharge capacity of 125mAh g−1 compared to 12 mAh g−1 for the non-annealed sample, which can be regarded as a partial coating by FePO4 as obtained from X-ray absorption spectroscopy analysis.
- Published
- 2021
43. Data-Centric Architecture for Self-Driving Laboratories with Autonomous Discovery of New Nanomaterials
- Author
-
Maria A. Butakova, Andrey V. Chernov, Oleg O. Kartashov, and Alexander V. Soldatov
- Subjects
Chemistry ,data-centric architecture ,autonomous nanomaterials discovery ,General Chemical Engineering ,data flow model ,self-driving laboratory ,General Materials Science ,QD1-999 ,Article - Abstract
Artificial intelligence (AI) approaches continue to spread in almost every research and technology branch. However, a simple adaptation of AI methods and algorithms successfully exploited in one area to another field may face unexpected problems. Accelerating the discovery of new functional materials in chemical self-driving laboratories has an essential dependence on previous experimenters’ experience. Self-driving laboratories help automate and intellectualize processes involved in discovering nanomaterials with required parameters that are difficult to transfer to AI-driven systems straightforwardly. It is not easy to find a suitable design method for self-driving laboratory implementation. In this case, the most appropriate way to implement is by creating and customizing a specific adaptive digital-centric automated laboratory with a data fusion approach that can reproduce a real experimenter’s behavior. This paper analyzes the workflow of autonomous experimentation in the self-driving laboratory and distinguishes the core structure of such a laboratory, including sensing technologies. We propose a novel data-centric research strategy and multilevel data flow architecture for self-driving laboratories with the autonomous discovery of new functional nanomaterials.
- Published
- 2022
44. Search for Analytical Relations between X-Ray Absorption Spectra Descriptors and the Local Atomic Structure Using Machine Learning
- Author
-
Alexander Algasov, Alexander V. Soldatov, Andrea Martini, Antonina N. Kravtsova, Sergey A. Guda, Aram L. Bugaev, Alexander A. Guda, and L. V. Guda
- Subjects
Physics ,Absorption spectroscopy ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Tangent ,Curvature ,Machine learning ,computer.software_genre ,Spectral line ,Surfaces, Coatings and Films ,Maxima and minima ,ComputingMethodologies_PATTERNRECOGNITION ,Absorption edge ,Position (vector) ,Artificial intelligence ,Maxima ,business ,computer - Abstract
In this paper, we develop a new technique for quantitative analysis of the near region of X-ray absorption spectra that is based on the extraction of spectrum descriptors and machine learning. The use of descriptors (edge position, intensity and curvature of minima and maxima, and tangent of the slope of the absorption edge) allows solution of the problem of systematic differences between theoretical calculations and experimental data, reducing the dimension of the problem and thereby improving the accuracy of machine-learning algorithms. We obtain analytical relations between the spectrum descriptors and the parameters of the local atomic structure of a substance, which extend the range of applicability of the empirical Natoli rule and analysis of the chemical shift of spectra to arbitrary classes of chemical compounds.
- Published
- 2021
45. XAS Diagnostic of the Photoactive State in Co(II) Azobenzene Complex in Organic Solvents
- Author
-
Sergey A. Mashchenko, Grigory Smolentsev, Svetlana O. Shapovalova, Valery G. Vlasenko, Alexander A. Guda, Anatolii V. Chernyshev, Anatolii S. Burlov, Andrey G. Starikov, and Alexander V. Soldatov
- Subjects
chemistry.chemical_compound ,X-ray absorption spectroscopy ,Materials science ,Azobenzene ,chemistry ,Spin transition ,General Chemistry ,Photochemistry - Published
- 2021
46. Efficiency of Heating Magnetite Nanoparticles with Different Surface Morphologies for the Purpose of Magnetic Hyperthermia
- Author
-
Alexander V. Soldatov and O. E. Polozhentsev
- Subjects
Diffraction ,Materials science ,Magnetometer ,Nanoparticle ,Coercivity ,Surfaces, Coatings and Films ,law.invention ,chemistry.chemical_compound ,Magnetic hyperthermia ,chemistry ,Chemical engineering ,law ,Transmission electron microscopy ,Magnetic nanoparticles ,Magnetite - Abstract
The magnetic and hyperthermia characteristics and the efficiency of heating (in an alternating magnetic field) magnetite nanoparticles with different surface morphologies are investigated. Spherical, cubic and elongated nanoparticles are synthesized by the solvothermal method using various precursors and stabilizers. The physical-chemical and hyperthermia characteristics of the obtained nanoparticles are studied by transmission electron microscopy, X-ray diffraction, vibration magnetometry, and magnetic hyperthermia. The average sizes of the spherical, cubic, and elongated nanoparticles are 18.5, 51.6, and 34.7 nm according to X-ray diffraction data and 23, 51.6, and 46.5 × 7.3 nm according to transmission electron microscopy data, respectively. The saturation magnetization varies from 51.5 emu/g for the spherical nanoparticles up to 84 emu/g for the cubic nanoparticles; the coercive force varies from 7.8 to 52.5 Oe, respectively. The hyperthermia characteristics of magnetite nanoparticles of different morphology are determined; the intrinsic loss power is found to be ILP = 2.72 nH m2/kg for the cubic nanoparticles and 1.54 nH m2/kg for the spherical ones. The obtained magnetic nanoparticles of magnetite of different morphologies can be considered as potential candidates for heat mediators for local magnetic hyperthermia.
- Published
- 2021
47. The Influence of Acetic Acid on the Properties of Microporous Metal–organic Framework MIL-88a at Microfluidic Conditions and room Temperature
- Author
-
Svetlana O. Shapovalova, A. A. Kuzharov, Vera V. Butova, Aleksei Fedorenko, Alexander V. Soldatov, Olga A. Burachevskaya, I. E. Gorban, Mikhail A. Soldatov, and P. V. Medvedev
- Subjects
Materials science ,Dispersity ,Biomedical Engineering ,Infrared spectroscopy ,Bioengineering ,Microporous material ,Condensed Matter Physics ,Thermogravimetry ,Acetic acid ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Transmission electron microscopy ,General Materials Science ,Metal-organic framework ,Electrical and Electronic Engineering ,Porosity ,Engineering (miscellaneous) - Abstract
This paper presents a new eco-friendly technique for the microfluidic synthesis of metal–organic framework MIL-88a in an aqueous medium at room temperature. Acetic acid as a modulator was used to control the morphology and size of the resulting particles during the synthesis. An increase of acetic acid concentration in a certain range of molar ratios leads to a decrease in the linear size of obtained particles and makes it possible to obtain a material with monodisperse porosity. The synthesized samples were comprehensively characterized by powder X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetry, and transmission electron microscopy. The porosity of the obtained materials was calculated according to the BET model, based on the data of low-temperature nitrogen adsorption.
- Published
- 2021
48. Glycopolymer-Based Materials: Synthesis, Properties, and Biosensing Applications
- Author
-
Mohammad R. Thalji, Amal Amin Ibrahim, Kwok Feng Chong, Alexander V. Soldatov, and Gomaa A. M. Ali
- Subjects
General Chemistry - Published
- 2022
49. Investigating the influence of Eu-doping on the structural and optical characterization of cadmium oxide thin films
- Author
-
A.A.M. Farag, M.I. Mohammed, V. Ganesh, H. Elhosiny Ali, A.M. Aboraia, Yasmin Khairy, H.H. Hegazy, V. Butova, Alexander V. Soldatov, H. Algarni, H.Y. Zahran, and I.S. Yahia
- Subjects
Electrical and Electronic Engineering ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Published
- 2023
50. Quantitative Analysis of X-Ray Spectral Data for a Mixture of Compounds Using Machine-Learning Algorithms
- Author
-
Sergey A. Guda, Alexander Algasov, Yu. V. Rusalev, Alexander A. Guda, and Alexander V. Soldatov
- Subjects
Materials science ,Absorption spectroscopy ,Component (thermodynamics) ,Spectrum (functional analysis) ,X-ray ,Spectral data ,Software package ,Quantitative analysis (chemistry) ,Algorithm ,Spectral line ,Surfaces, Coatings and Films - Abstract
Based on machine-learning algorithms, a method is developed for determining the structural parameters of the components of a mixture from X-ray absorption spectra. For each component, a database of spectra is constructed for all possible deformations of its structure. The machine-learning method implemented in the PyFitIt software package allows quick calculation of the spectrum for deformations of structures from the considered family and optimization of the structural parameters of the mixture by fitting the theoretical spectrum to the experimental one. The capabilities of the method are examined by analyzing changes in the structural characteristics and concentrations of the components of the mixture for the bis-dioxolene complex of cobalt with functionalized iminopyridine ligands during its valence-tautomeric interconversion depending on temperature.
- Published
- 2021
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.