1,361 results on '"Skvortsov, A"'
Search Results
2. SARS-CoV-2 introductions to the island of Ireland: a phylogenetic and geospatiotemporal study of infection dynamics.
- Author
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Rice, Alan M., Troendle, Evan P., Bridgett, Stephen J., Firoozi Nejad, Behnam, McKinley, Jennifer M., Bradley, Declan T., Fairley, Derek J., Bamford, Connor G. G., Skvortsov, Timofey, and Simpson, David A.
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PUBLIC health surveillance ,SARS-CoV-2 Omicron variant ,WHOLE genome sequencing ,COVID-19 pandemic ,COUNTRY of origin (Immigrants) ,PARSIMONIOUS models - Abstract
Background: Ireland's COVID-19 response combined extensive SARS-CoV-2 testing to estimate incidence, with whole genome sequencing (WGS) for genome surveillance. As an island with two political jurisdictions―Northern Ireland (NI) and Republic of Ireland (RoI)―and access to detailed passenger travel data, Ireland provides a unique setting to study virus introductions and evaluate public health measures. Using a substantial Irish genomic dataset alongside global data from GISAID, this study aimed to trace the introduction and spread of SARS-CoV-2 across the island. Methods: We recursively searched for 29,518 SARS-CoV-2 genome sequences collected in Ireland from March 2020 to June 2022 within the global SARS-CoV-2 phylogenetic tree and identified clusters based on shared last common non-Irish ancestors. A maximum parsimony approach was used to assign a likely country of origin to each cluster. The geographic locations and collection dates of the samples in each introduction cluster were used to map the spread of the virus across Ireland. Downsampling was used to model the impact of varying levels of sequencing and normalisation for population permitted comparison between jurisdictions. Results: Six periods spanning the early introductions and the emergence of Alpha, Delta, and Omicron variants were studied in detail. Among 4439 SARS-CoV-2 introductions to Ireland, 2535 originated in England, with additional cases largely from the rest of Great Britain, United States of America, and Northwestern Europe. Introduction clusters ranged in size from a single to thousands of cases. Introductions were concentrated in the densely populated Dublin and Belfast areas, with many clusters spreading islandwide. Genetic phylogeny was able to effectively trace localised transmission patterns. Introduction rates were similar in NI and RoI for most variants, except for Delta, which was more frequently introduced to NI. Conclusions: Tracking individual introduction events enables detailed modelling of virus spread patterns and clearer assessment of the effectiveness of control measures. Stricter travel restrictions in RoI likely reduced Delta introductions but not infection rates, which were similar across jurisdictions. Local and global sequencing levels influence the information available from phylogenomic analyses and we describe an approach to assess the ability of a chosen WGS level to detect virus introductions. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Prediction of Characteristics of Inductive Coupled Radio Frequency Discharge at Low Pressure in One-Dimensional Approximation Using Neural Network Approach.
- Author
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Skvortsov, I. V., Shemakhin, A. Y., Danilov, I. Y., and Gaskova, D. A.
- Abstract
The paper presents the results of predicting the characteristics of a inductive coupled radio frequency discharge at low pressure in a one-dimensional approximation using a perceptron. The electric and magnetic field strengths of the ICRF discharge were used as prediction characteristics. The prediction results obtained using the perceptron were compared with the model data of the ICRF discharge. The comparative results showed that the trained perceptron can be used to predict the characteristics of the ICRF discharge at those points of study where it is problematic to obtain a solution due to the convergence of mathematical models. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Different metrics in the problem of ideals for the algebra H^\infty.
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Kislyakov, S. V. and Skvortsov, A. A.
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- 2024
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5. Visual-Spatial Search in Neglect Syndrome as a Function of the Number of Stimuli in the Hemifields.
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Varako, Nataliya, Kovyazina, Maria, Yurina, Daria, Propustina, Victoria, Stepanov, Georgiy, Vasilyeva, Svetlana, Daminov, Vadim, Skvortsov, Anatoliy, Baulina, Maria, and Zinchenko, Yuri
- Abstract
Background: Neglect syndrome is a serious condition that often affects the ability to perform visual-spatial search tasks, interfering with the ability to detect stimuli on the left side of space. A number of factors can affect the success of visual search in patients with neglect syndrome, including visual field load. The purpose of this study is to investigate how the number of stimuli in the right visual hemifield influences the efficiency of visual search in the left (neglected) hemifield, hypothesizing that an increased object load on the right side may impair search performance on the left. Methods: The sample comprised 30 patients with neglect syndrome as the target group and 20 patients with right hemisphere damage but no signs of hemispatial neglect as the control group. This study employed several neuropsychological tests, including neuropsychological examination according to the scheme of A.R. Luria. The SPSS 23.0 software was used for statistical analysis of the data. Results: The Red Shapes test revealed a significant decrease in the number of stimuli detected in both the right and left visual hemifields across successive series (p < 0.001) in patients within the target group. No significant differences were observed in the participants of the control group. This study's results may be explained by the phenomenon of SSM (subsequent search misses) and the theory of attentional resource depletion during visual search tasks. These results indicate the need for further research into the features of visual search under various conditions, including the load and structuredness of the visual field. Conclusions: This study confirmed that the number of elements in the right visual hemifield influences the ability to detect elements in the left hemifield in patients with left-sided neglect, as demonstrated using the Red Shapes test. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Nanoformulation of the Photoactive Cisplatin Prodrug for Combined Photothermal Therapy and Bioimaging.
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Spector, Daniil V., Bykusov, Vladislav, Zharova, Anastasia, Kuzmichev, Ilia, Isaeva, Yulia A., Khaydukov, Evgeny V., Trifanova, Ekaterina, Stepanov, Maxim, Erofeev, Alexander S., Gorelkin, Petr, Kuanaeva, Regina, Nikitina, Vita N., Dubenskii, Alexander, Maksimova, Yulia, Skvortsov, Dmitry Aleksandrovich, Ipatova, Daria, Rodin, Igor A., Vokuev, Mikhail F., Martynov, Alexander G., and Bunin, Dmitry
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Cancer phototheranostics is a new mode of precise treatment based on fluorescent and photothermal imaging (PTI), combined with photodynamic (PDT) and photothermal therapy (PTT). Herein, we designed a photoactive Pt-(IV) prodrug Pt-1 with BODIPY-based triplet photosensitizer as an axial ligand that exhibits cytotoxic effects through both PDT and photoactivated chemotherapy (PACT). Based on the Pt-1 prodrug, we developed a multifunctional theranostic nanoplatform Pt-NPs with combined PDT/PTT activity, capable of light-induced cisplatin release and suitable for photothermal and fluorescent tumor imaging. Upon 660 nm laser irradiation, Pt-NPs efficiently causes regional hyperpyrexia, with a photothermal conversion efficiency of 42.1%. Synergistically, Pt-NPs acts as a PDT type I agent. In vivo PTI studies have shown bright fluorescence of the CT-26 tumor after intravenous injection of Pt-NPs, indicating accumulation and retention of Pt-NPs in the tumor. This is the first example of PTT/PDT-active NPs based on Pt-(IV) prodrug capable of photoinduced release of cisplatin. This strategy of the synergistic light-induced PDT/PTT/PACT action of Pt-NPs provides a new platform for the future design of phototheranostic agents for enhanced tumor treatment and imaging. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Targeted Biofeedback Training to Improve Gait Parameters in Subacute Stroke Patients: A Single-Blind Randomized Controlled Trial.
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Skvortsov, Dmitry V., Kaurkin, Sergey N., and Ivanova, Galina E.
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STROKE ,STROKE patients ,GAIT in humans ,BIOMECHANICS ,ACTIVITIES of daily living ,BIOFEEDBACK training ,TRANSCRANIAL direct current stimulation - Abstract
Biofeedback (BFB) is a rehabilitation method, which, among other things, is used for the restitution of motor and gait function. As of now, it has become technically feasible to use BFB training based on target gait parameters to improve the gait function in stroke patients. The walking patterns of stroke patients are generally characterized by significant gait phase asymmetries, mostly of the stance phase and the single stance phase. The aim of the study was to investigate the restoration of gait function using BFB training with gait phases as feedback targets. The study included two patient groups, each of 20 hemiparetic patients in the subacute stage of stroke and a control group of 20 healthy subjects. Each patient group received BFB training with either stance phase or single stance phase as the feedback target, respectively. The patients received a total of 8 to 11 training sessions. Assessments based on clinical scales and gait analysis data (spatiotemporal, kinematic, and EMG parameters) were performed before and after the training course. The score-based clinical assessments showed a significant improvement in both patient groups. According to the assessments of gait biomechanics, the subjects in the Single Stance Phase group had significantly more severe dysfunctions. In both patient groups, the unaffected limb responded to the BFB training, while the stance phase significantly changed after training in the unaffected limb only. The other patient group, trained using the single stance phase as the feedback target, showed no changes in the target parameter either in the affected or in the contralateral limb. The clinical and instrumental assessments showed different, non-equivalent sensitivity. The results of the study demonstrated the possibility to use targeted BFB training to improve walking function. However, a significant effect of such training was only observed with stance phase as the target parameter. A response to training was observed predominantly in the unaffected limb and facilitated the desired increase in the functional ability of the paretic limb. Training based on stance phase as the target parameter is probably preferable for the patient population under study. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Intermittency of gravity wave turbulence on the surface of an infinitely deep fluid: directional effects.
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Kirezci, Cagil, Skvortsov, Alexei T., Sgarioto, Daniel, and Babanin, Alexander V.
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This study investigates the influence of surface wave characteristics, specifically wave steepness and directional spreading, on intermittency in deep-water gravity wave turbulence through long-term numerical simulations of three-dimensional potential fully nonlinear periodic gravity waves. We conducted this investigation by estimating the scaling exponent of the surface elevation under different sea state conditions. With our numerical methods, we were able to evaluate the scaling exponents of the structure-function up to 12th order. The observed increased intermittency in directionally narrower sea states and in higher steepness conditions aligns with known effects of quasi-resonant wave–wave interactions and wave breaking. Comparative analyses reveal that both the conventional She–Leveque model and the multifractal models, also used to represent intermittency in wave turbulence of a different nature, exhibit a strong correlation in this study. This observation underscores the universality of intermittency phenomena within wave turbulence. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Anomalous Diffusion by Ocean Waves and Eddies.
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Voermans, Joey J., Babanin, Alexander V., Skvortsov, Alexei T., Kirezci, Cagil, Gamaleldin, Muhannad W., Rapizo, Henrique, Pezzi, Luciano P., Santini, Marcelo F., and Heil, Petra
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OIL spill management ,SEARCH & rescue operations ,HEAD waves ,WIND measurement ,SURFACE forces ,OCEAN waves ,OCEAN currents - Abstract
Understanding the dispersion of floating objects and ocean properties at the ocean surface is crucial for various applications, including oil spill management, debris tracking and search and rescue operations. While mesoscale turbulence has been recognized as a primary driver of dispersion, the role of submesoscale processes is poorly understood. This study investigates the largely unexplored mechanism of dispersion by refracted wave fields. In situ observations demonstrate significantly faster and distinct dispersion patterns for objects influenced by wind, waves and currents compared to those solely driven by ocean currents. Numerical simulations of wave fields refracted by ocean eddies corroborate these findings, revealing diffusivities that exceed those of turbulent diffusion at scales up to 10 km during energetic sea states. Our results highlight the importance of ocean waves in dispersing surface material, suggesting that refracted wave fields may play a significant role in submesoscale spreading. As atmospheric forcing at the ocean surface will only strengthen due to anthropogenic contributions, additional research into wave refraction is necessary. This requires concurrent high-resolution measurements of wind, waves and currents to inform the revisions of large-scale coupled models to better include the submesoscale physics. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Polypropylene Crystallinity Reduction through the Synergistic Effects of Cellulose and Silica Formed via Sol–Gel Synthesis.
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Shambilova, Gulbarshin K., Iskakov, Rinat M., Bukanova, Aigul S., Kairliyeva, Fazilat B., Kalauova, Altynay S., Kuzin, Mikhail S., Novikov, Egor M., Gerasimenko, Pavel S., Makarov, Igor S., and Skvortsov, Ivan Yu.
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CRYSTALLINE polymers ,FUSED deposition modeling ,DYNAMIC mechanical analysis ,DIFFERENTIAL scanning calorimetry ,THREE-dimensional printing - Abstract
This study focuses on the development of environmentally sustainable polypropylene (PP)-based composites with the potential for biodegradability by incorporating cellulose and the oligomeric siloxane ES-40. Targeting industrial applications such as fused deposition modeling (FDM) 3D printing, ES-40 was employed as a precursor for the in situ formation of silica particles via hydrolytic polycondensation (HPC). Two HPC approaches were investigated: a preliminary reaction in a mixture of cellulose, ethanol, and water, and a direct reaction within the molten PP matrix. The composites were thoroughly characterized using rotational rheometry, optical microscopy, differential scanning calorimetry, and dynamic mechanical analysis. Both methods resulted in composites with markedly reduced crystallinity and shrinkage compared to neat PP, with the lowest shrinkage observed in blends prepared directly in the extruder. The inclusion of cellulose not only enhances the environmental profile of these composites but also paves the way for the development of PP materials with improved biodegradability, highlighting the potential of this technique for fabricating more amorphous composites from crystalline or semi-crystalline polymers for enhancing the quality and dimensional stability of FDM-printed materials. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Monomeric and Dimeric Boron (III) Subphthalocyanines Functionalized with 4‐Hydroxy‐Benzoic Acid as Potential Photosensitizers and Photocatalysts in Sulfoxidation.
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Skvortsov, Ivan A., Filatova, Elizaveta O., Birin, Kirill P., Kalyagin, Aleksandr A., Chufarin, Alexey E., Lapshina, Daria A., Shagalov, Evgeny V., and Stuzhin, Pavel A.
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REACTIVE oxygen species ,CHEMICAL decomposition ,SQUARE waves ,CYCLIC voltammetry ,PHOTOCATALYSTS - Abstract
Axial modification of boron (III) subphthalocyanine bromides with 4‐hydroxy‐benzoic acid successfully led to the formation of the macrocycles with anchored 4‐carboxyphenoxy group [RsPcPHBA] (R=tBu, H) in the axial position and to a new dimer [sPcPHBAsPc] as minor product. Tri‐tert‐butyl and unsubstituted subphthalocyanines bearing benzoate ([tBusPcBA], [sPcBA]), phenoxy‐group ([tBusPcOPh], [sPcOPh])) in the axial position, have been also investigated as well as control sPcs. All compounds were characterized by NMR, IR, UV‐Vis and mass spectrometry. The electrochemical properties were studied using cyclic voltammetry (CV) and square wave voltammetry (SWV). Singlet oxygen generation was systematically measured for all synthesized [RsPcX] by kinetic method of chemical trap decomposition (DPBF) and by determination of phosphorescence of singlet oxygen (at 1270 nm). Axially modified subphthalocyanines exhibit high quantum yields of singlet oxygen (1O2) generation (0.47–0.62). The observed exceptional photostability in oxygen‐saturated ethanol or toluene solutions and high 1O2 quantum yields allows to use [tBusPcPHBA] as photocatalysts of selective oxidative transformations of organic sulfides to sulfoxides. Loading the catalyst to 9.7 ⋅ 10−2 mol % made it possible to achieve complete conversion of the substrate (TON up to 1700). [ABSTRACT FROM AUTHOR]
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- 2024
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12. Influence of the regeneration method of irradiated mixture "30% TBP in Isopar-M" on the lower temperature limit of flame propagation.
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Serenko, Yulia V., Skvortsov, Ivan V., Smirnov, Anton V., and Belova, Elena V.
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REACTOR fuel reprocessing ,FLAME temperature ,FRACTIONAL distillation ,FIRE prevention ,LOW temperatures - Abstract
When a circulating extraction mixture of 30% TBP in Isopar-M, saturated with 3.4 mol L
−1 nitric acid, is irradiated with a dose of up to 2000 kGy, products are formed that reduce the value of the lower temperature limit of flame propagation (Tl ) from 74 to 52 ℃ and worsen the hydrodynamic properties. A comparison of regeneration methods of an irradiated extraction mixture showed that the method of fractional vacuum distillation is the most effective for increasing the Tl value. Regeneration with carbonate solutions increases Tl , removes non-volatile radiolysis products, and moreover is the simplest and most economical regeneration method. [ABSTRACT FROM AUTHOR]- Published
- 2024
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13. From higher-spin gauge interactions to Compton amplitudes for root-Kerr.
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Cangemi, Lucile, Chiodaroli, Marco, Johansson, Henrik, Ochirov, Alexander, Pichini, Paolo, and Skvortsov, Evgeny
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We develop massive higher-spin theory as a framework for describing dynamics of rotating compact objects, such as Kerr black holes. In this paper, we explore gauge interactions up to quartic order and corresponding Compton amplitudes of higher-spin massive objects coupled to electromagnetism and Yang-Mills theory. Their classical counterparts are known as root-Kerr gauge-theory solutions, whose amplitudes are closely related to those of Kerr black holes. We use three distinct approaches: (i) massive higher-spin gauge symmetry to introduce cubic interactions for all spins and the quartic interactions up to spin 3, which is implemented both off shell and via Ward identities; (ii) a chiral higher-spin approach to construct quartic Lagrangians with correct degrees of freedom to all spins; (iii) on-shell functional patterns before and after taking the classical limit to constrain the Compton amplitudes. As final results, we arrive at simple local formulae for the candidate root-Kerr Compton amplitudes both in the quantum regime and classical limit, to all orders in spin. This is a precursor to the gravitational Kerr case, which is presented in a follow-up paper. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Molecular structure, thermodynamic and spectral characteristics of chloroboron(III) subphthalocyanine and its dodecafluorinated derivative.
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Kurochkin, Ivan Yu., Pogonin, Alexander E., Eroshin, Alexey V., Zhabanov, Yuriy A., Krasnova, Olga G., Skvortsov, Ivan A., Stuzhin, Pavel A., Giricheva, Nina I., and Girichev, Georgy V.
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- 2024
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15. Long-Term Outcomes of Anterior Cruciate Ligament Reconstruction Based on Gait Analysis.
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Skvortsov, Dmitry, Altukhova, Alyona, Kaurkin, Sergey, and Akhpashev, Alexander
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ANTERIOR cruciate ligament surgery ,ANTERIOR cruciate ligament ,KNEE joint ,WALKING speed ,HIP joint - Abstract
Background: Currently available studies on the long-term functional outcomes of anterior cruciate ligament (ACL) reconstruction have yielded conflicting results. The purpose of this study was to evaluate the biomechanical characteristics of walking in the long term after ACL reconstruction. Methods: The study included a test group of 18 patients (3.4 years from the date of ACL reconstruction on average) and a control group of 20 healthy subjects. Their gaits were assessed using functional tests at voluntary walking and fast-walking speeds. The biomechanical assessments utilized included spatiotemporal and kinematic parameters of walking, as well as surface electromyography (EMG) amplitudes of the main flexor-extensor muscles of the lower extremities. Results: Fast-walking speeds and the clearances of the operated-upon limbs in the patient group exceeded those in the control group. The gait cycle in the patient group was significantly longer when walking at a voluntary speed compared to the control group. In the patient group, most of the movements were symmetrical at both speeds, and the parameters did not differ from the control group. The only exception was the hip joint amplitude and the main amplitude of the knee joint flexion, which significantly and simultaneously increased when walking at a fast speed. Conclusions: In the postoperative period, at voluntary speeds, the patient group was characterized by increased amplitudes in the hip and knee joints and higher EMG amplitudes, which almost disappeared at higher speeds. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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16. Functional Tests of the Abdominal Wall Muscles in Normal Subjects and in Patients with Diastasis and Oblique Inguinal Hernias in a Pilot Study.
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Skvortsov, Dmitry, Cherepanin, Andrei, Fadeeva, Yulia, Timonin, Andrey, and Nosenko, Nataly
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TRANSVERSUS abdominis muscle ,ABDOMINAL wall ,INGUINAL hernia ,HERNIA ,VALSALVA'S maneuver ,ABDOMINAL muscles - Abstract
Objectives: To identify typical patterns of abdominal wall muscle activation in patients with diastasis recti and inguinal hernias compared to controls during the Valsalva maneuver, voluntary coughing, and physical activity. Methods: The study included 15 subjects: 5 with diastasis recti, 4 with inguinal hernias, and 6 healthy controls. The functions of rectus abdominis (RA) and external oblique (OE) muscles were measured by surface electromyography (sEMG). Using ultrasound, the thicknesses of the RA, OE, internal oblique (IO), and transversus abdominis (TA) muscles were assessed as well as the echo intensity (EI) of RA and OE. Results: We found a significant effect of the type of abdominal wall pathology on the maximum sEMG amplitude (p = 0.005). There was a reliable trend in maximum sEMG amplitude, with the highest one in diastasis recti and a significantly lower one in inguinal hernias. Duncan's test showed a significant difference in muscle thickness, both on the right and left sides, between patients with diastasis and controls, but only on the left side between patients with diastasis and those with inguinal hernia (p < 0.05). Conclusions: The abdominal wall pathology results in a change in the function and structure of the abdominal muscles, which can be detected using electromyography and ultrasound examination. The presence of diastasis recti is accompanied by an increase in bioelectrical activity and a decrease in thickness. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Distributed Estimation of Fields Using a Sensor Network with Quantized Measurements.
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Jayasekaramudeli, Chethaka, Leong, Alex S., Skvortsov, Alexei T., Nielsen, David J., and Ilaya, Omar
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DIFFUSION measurements ,SENSOR networks ,SCALAR field theory ,DISTRIBUTED algorithms ,TIME-varying systems - Abstract
In this paper, the problem of estimating a scalar field (e.g., the spatial distribution of contaminants in an area) using a sensor network is considered. The sensors are assumed to have quantized measurements. We consider distributed estimation algorithms where each sensor forms its own estimate of the field, with sensors able to share information locally with its neighbours. Two schemes are proposed, called, respectively, measurement diffusion and estimate diffusion. In the measurement diffusion scheme, each sensor broadcasts to its neighbours the latest received measurements of every sensor in the network, while in the estimate diffusion scheme, each sensor will broadcast local estimates and Hessians to its neighbours. Information received from its neighbours will then be iteratively combined at each sensor to form the field estimates. Time-varying scalar fields can also be estimated using both the measurement diffusion and estimate diffusion schemes. Numerical studies illustrate the performance of the proposed algorithms, in particular demonstrating steady state performance close to that of centralized estimation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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18. Nuclear Scanning Microprobe Analysis of Silicon Carbide Epilayers.
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Buzoverya, M. E., Karpov, I. A., Arkhipov, A. Yu., Skvortsov, D. A., Neverov, V. A., and Mamin, B. F.
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The surfaces of homoepitaxial 4H-SiC layers were studied using a nuclear scanning microprobe in the Rutherford backscattering mode. Analysis of the state of the sample surfaces and the synthesis conditions showed that an increase in the silicon (Si) content in the upper layers of some samples precedes the formation of highly defective 4H-SiC layers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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19. A Methodology for Forecasting the KPIs of a Region's Development: Case of the Russian Arctic.
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Zhukovskiy, Yuriy, Tsvetkov, Pavel, Koshenkova, Anastasia, Skvortsov, Ivan, Andreeva, Iuliia, and Vorobeva, Valeriya
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Forecasting the development of regions is one of the most challenging tasks of modern economics. The quality of any forecast is determined by the methodology used. Accordingly, criticism of existing forecasts is largely connected to their methodological approaches. In this paper, a multi-level approach to forecasting the development of the region is proposed, starting with the definition of the key performance indicators and ending with the assessment of various scenarios. The study was conducted on the example of the Russian Arctic, divided into three technological zones, with three scenarios of the development for each (negative, base, positive). The application of the proposed methodology allowed for modeling the development of the region until 2035. The results show that the Russian Arctic has a huge difference in the achievability of different goals, e.g., 98% of the electricity supply targets are achievable in a baseline scenario, while only 52% are achievable in a set of "navigation" targets. The proposed methodology can be useful for diving into the details of regional forecasts, such as the impact of key companies in a region or the influence of international politics. [ABSTRACT FROM AUTHOR]
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- 2024
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20. Behavior of a stationary jet of concentrated polyacrylonitrile solution.
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Skvortsov, I. Yu., Kuzin, M. S., Gerasimenko, P. S., Patsaev, T. D., Subbotin, A. V., and Kulichikhin, V. G.
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SOLID solutions ,SEPARATION of gases ,ATMOSPHERIC temperature ,FIBERS ,HUMIDITY ,PHASE separation - Abstract
The fiber formation process via the uniaxial stretching jet of concentrated polyacrylonitrile solutions in dimethyl sulfoxide has been investigated. Data on viscoelastic properties obtained by oscillatory shear rheometry have been compared with the evolution of jet thinning during stretching. It was found that at a fixed temperature and moderate air humidity (20%), the jet thinning process involves an initial rapid viscous thinning followed by phase separation and the formation of solid fibers coated with solvent droplets. Changes in morphology as the solution transforms into solid fiber were analyzed using cryo-microscopy. It was demonstrated that at the final thinning stages there exists an increase in a solvent concentration in the near-surface layers of the jet/fiber. Finally, the role of air humidity was analyzed. Two possible scenarios of fiber formation were considered: predominantly due to uniaxial deformation or through coagulation of solution with moisture from the air humidity. Comparative morphological analysis of prepared fiber cross sections showed that monolithic fibers with homogeneous transverse morphology are obtained in the case of strain-induced formation. In contrast, fibers obtained due to phase separation induced by air humidity have gradient porosity. The mechanisms underlying the observed behavior are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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21. Massive spin three-half field in a constant electromagnetic background.
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Delplanque, William and Skvortsov, Evgeny
- Abstract
Massive higher-spin fields are difficult to introduce consistent interactions, including electromagnetic and gravitational ones which are clearly exhibited by (non-elementary) higher-spin particles in nature. We construct an action that describes consistent interactions of massive spin three-half field with a constant electromagnetic background. We also work out the relation to the chiral approach. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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22. Physico−mathematical model of the voltage−current characteristics of light-emitting diodes with quantum wells based on the Sah−Noyce−Shockley recombination mechanism.
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Manyakhin, Fedor I., Varlamov, Dmitry O., Krylov, Vladimir P., Morketsova, Lyudmila O., Skvortsov, Arkady A., and Nikolaev, Vladimir K.
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- 2024
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23. Robotics and artificial intelligence as representatives of a fundamentally new legal personality.
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Petrogradskaya, Albina and Skvortsov, Sergey
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- 2024
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24. Analysis of directions for application of artificial intelligence systems in analysis of the state of water resources.
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Semin, A.N., Skvortsov, E.A., and Pryadilina, N.K.
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- 2024
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25. Analysis of directions for application of artificial intelligence systems in soil condition analysis.
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Yalunina, E.N., Skvortsov, E.A., and Gusev, A.S.
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- 2024
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26. The effect of complex fertilizers on the productivity of potato varieties on reclaimed lands in the Central Agricultural District of the Russian Federation.
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Pavlov, M.N., Drozdov, I.A., Akimov, A.A., Skvortsov, S.S., and Ivanyutina, N.N.
- Published
- 2024
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27. Permeability and diffusion resistance of porous membranes: Analytical theory and its numerical test.
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Skvortsov, Alexei T., Dagdug, Leonardo, Hilder, Emily F., Berezhkovskii, Alexander M., and Bezrukov, Sergey M.
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BIOENGINEERING ,CYTOLOGY ,MEMBRANE permeability (Biology) ,PERMEABILITY ,CELL physiology ,DIFFUSION - Abstract
This study is devoted to the transport of neutral solutes through porous flat membranes, driven by the solute concentration difference in the reservoirs separated by the membrane. Transport occurs through membrane channels, which are assumed to be non-overlapping, identical, straight cylindrical pores connecting the reservoirs. The key quantities characterizing transport are membrane permeability and its diffusion resistance. Such transport problems arising in very different contexts, ranging from plant physiology and cell biology to chemical engineering, have been studied for more than a century. Nevertheless, an expression giving the permeability for a membrane of arbitrary thickness at arbitrary surface densities of the channel openings is still unknown. Here, we fill in the gap and derive such an expression. Since this expression is approximate, we compare its predictions with the permeability obtained from Brownian dynamics simulations and find good agreement between the two. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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28. Compression and interpenetration of adsorption-active brushes.
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Ivanova, Anna S., Polotsky, Alexey A., Skvortsov, Alexander M., Klushin, Leonid I., and Schmid, Friederike
- Subjects
DENSITY - Abstract
Compression and interpenetration of two opposing polymer brushes formed by end-grafted adsorption-active chains are studied by the numerical self-consistent field approach and by analytical theory. For sufficiently strong polymer–surface attraction, a fraction of chains in the adsorption-active brush condenses into a near-surface layer, while the remaining ones form the outer brush with reduced effective grafting density. Analysis shows that the normal pressure in adsorption-active brushes can be understood in terms of the effective grafting density concept although the pressure at small separations is affected by the presence of the dense adsorbed phase. We propose a simple theory modification that accounts for this effect. We also formulate a procedure for extracting the value of the effective grafting density directly from the pressure vs separation curves by inverting the equation of state. In contrast to the normal pressure, the interpenetration of the two opposing adsorption-active brushes demonstrates a much more intricate behavior. At weak to moderate compressions, the effective grafting density concept works well but fails spectacularly at small interbrush separations. We identify two interpenetration regimes for adsorption-active brushes: (i) at separations larger than the ideal Gaussian coil size N
1/2 , the overlap of the two brushes is concentrated in the mid-plane region, in the same way as in brushes grafted onto non-attractive surfaces; (ii) at separations less than N1/2 , the brush overlap is strongly enhanced in the wall regions where the attractive interaction plays an important role both in generating the dense layer for the "proper" brush and in attracting the "foreign" chains. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
29. Diffusion toward a nanoforest of absorbing pillars.
- Author
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Grebenkov, Denis S. and Skvortsov, Alexei T.
- Subjects
COLUMNS ,PROTEIN fractionation ,MATERIALS science ,GEOMETRIC modeling - Abstract
Spiky coatings (also known as nanoforests or Fakir-like surfaces) have found many applications in chemical physics, material sciences, and biotechnology, such as superhydrophobic materials, filtration and sensing systems, and selective protein separation, to name but a few. In this paper, we provide a systematic study of steady-state diffusion toward a periodic array of absorbing cylindrical pillars protruding from a flat base. We approximate a periodic cell of this system by a circular tube containing a single pillar, derive an exact solution of the underlying Laplace equation, and deduce a simple yet exact representation for the total flux of particles onto the pillar. The dependence of this flux on the geometric parameters of the model is thoroughly analyzed. In particular, we investigate several asymptotic regimes, such as a thin pillar limit, a disk-like pillar, and an infinitely long pillar. Our study sheds light onto the trapping efficiency of spiky coatings and reveals the roles of pillar anisotropy and diffusional screening. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
30. Fixed Point Theorems and Hardy Classes.
- Author
-
Kislyakov, S. V. and Skvortsov, A. A.
- Subjects
INTERPOLATION - Abstract
A survey of several recent applications of fixed point theorems for multivalued maps to interpolation of Hardy classes and to certain topics related to the corona theorem. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Galerkin Method and Parallel Algorithm for Solving the Problem of EM-Wave Propagation in a Locally Inhomogeneous Medium with a Graphene Layer at the Boundary of the Inhomogeneity Domain.
- Author
-
Skvortsov, O. S. and Tsupak, A. A.
- Abstract
Propagation of electromagnetic wave in locally inhomogeneous medium with an infinitely thin graphene layer is studied. New hybrid integro-differential equation is considered; for its numerical solving Galerkin method with compactly supported basis functions is applied. Parallel algorithm using MPI routines is implemented to obtain approximate solutions of the problem according to the Galerkin method. Several results of numerical tests showing convergence of the method are presented. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Collective acoustic modes of a bubble plume.
- Author
-
Skvortsov, Alexei T., MacGillivray, Ian R., Moore, Stephen, Manasseh, Richard, and Kocan, Martin
- Abstract
We derive a simple formula for the lowest natural frequencies of an infinitely long bubble plume with arbitrary cross section. Expressions are derived in terms of bubble volume fraction and equivalent radius of the plume, and a criterion for the existence of collective modes is established. For the plume with the circular cross section, our analytical approach is validated with the results of previous studies and numerical solution. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Low spin solutions of higher spin gravity: BPST instanton.
- Author
-
Skvortsov, Evgeny and Yin, Yihao
- Abstract
Higher spin gravities do not have a low energy limit where higher-spin fields decouple from gravity. Nevertheless, it is possible to construct fine-tuned exact solutions that activate low-spin fields without sourcing the higher-spin fields. We show that BPST (Belavin-Polyakov-Schwartz-Tyupkin) instanton is an exact solution of Chiral Higher Spin Gravity, i.e. it is also a solution of the holographic dual of Chern-Simons matter theories. This gives an example of a low-spin solution. The instanton sources the opposite helicity spin-one field and a scalar field. We derive an Effective Field Theory that describes the coupling between an instanton and the other two fields, whose action starts with the Chalmers-Siegel action and has certain higher derivative couplings. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Quantification of 11 metabolites in rat urine after exposure to organophosphates.
- Author
-
Leninsky, Michael A., Sobolev, Vladislav E., Sokolova, Margarita O., Voitenko, Natalya G., and Skvortsov, Nikita V.
- Subjects
LABORATORY rats ,URINE ,METABOLITES ,RATS ,CREATININE ,LACTIC acid ,ORGANOPHOSPHORUS pesticides - Abstract
Background: The aim of the study was to develop a technique for quantitative determination of rat urine metabolites by HPLC–MS/MS, which can be used to search for biomarkers of acute intoxication with organophosphates (OPs). Results: The content of metabolites in the urine of rats exposed to a single dose of paraoxon (POX1x); interval, twice daily administration of paraoxon (POX2x); exposure to 2-(o-cresyl)-4H-1, 3, 2-benzodioxaphosphorin-2-oxide and paraoxon (CBPOX) was investigated. New data were obtained on the content in the urine of intact rats as well as rats in 3 models of OP poisoning: 3-methylhistidine, threonine, creatine, creatinine, lactic acid, acetylcarnitine, inosine, hypoxanthine, adenine, 3-hydroxymethyl-butyrate and 2-hydroxymethyl-butyrate. Conclusions: The proposed assay procedure is a simple and reliable tool for urine metabolomic studies. Within 1–3 days after OP exposure in all three models of acute intoxication, the concentration of metabolites in rat urine, with the exception of adenine, changes similarly and symmetrically, regardless of the method of poisoning modeling, in all three models of acute intoxication. Further studies are needed to determine the specificity and reliability of using urinary metabolite concentration changes as potential biomarkers of acute organophosphate intoxication. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Asymmetric sound scattering by gratings of monopolar and dipolar resonators in a viscoelastic materiala).
- Author
-
McIntosh, Alexander G. D., Sharma, Gyani Shankar, Skvortsov, Alexei, MacGillivray, Ian, and Kessissoglou, Nicole
- Subjects
SOUND wave scattering ,RESONATORS ,ACOUSTICAL materials ,SCATTERING (Physics) ,EQUATIONS of motion ,MULTIPLE scattering (Physics) - Abstract
A self-consistent analytical model of a locally resonant coating exhibiting strong asymmetric wave scattering is presented. Gratings of resonant inclusions composed of cavities and hard particles embedded in a soft matrix are translated to the problem of sound scattering by monopolar and dipolar type resonators in a one-dimensional waveguide. Equations of motion for gratings of cavities and hard particles are developed that incorporate added mass, damping, and restoration forces to take into account multiple scattering effects. Expressions for the impedances of the resonators are derived from which the particle velocity fields are obtained. Monopole and dipole strengths are also calculated in terms of polarizability tensor components, which in turn are obtained from a retrieval method. Sound scattering by monopolar and dipolar resonators of different size and distribution within the waveguide are examined. Using detailed understanding of the interaction between groups of resonators, optimized solutions for a new class of acoustic materials can be designed by selecting layers of resonators to produce a given response. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Strong homotopy algebras for chiral higher spin gravity via Stokes theorem.
- Author
-
Sharapov, Alexey, Skvortsov, Evgeny, and Van Dongen, Richard
- Abstract
Chiral higher spin gravity is defined in terms of a strong homotopy algebra of pre-Calabi-Yau type (noncommutative Poisson structure). All structure maps are given by the integrals over the configuration space of concave polygons and the first two maps are related to the (Shoikhet-Tsygan-)Kontsevich Formality. As with the known formality theorems, we prove the A
∞ -relations via Stokes’ theorem by constructing a closed form and a configuration space whose boundary components lead to the A∞ -relations. This gives a new way to formulate higher spin gravities and hints at a construct encompassing the known formality theorems. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
37. DFT and TD DFT study of oxodiboron(III) phthalocyanine and peculiarities of spectral behavior and acid–base properties of its tert-butyl substituted derivative in solutions.
- Author
-
Nikitin, Ivan A., Popkov, Artem D., Skvortsov, Ivan A., and Stuzhin, Pavel A.
- Subjects
REACTIVE oxygen species ,MOLECULAR structure ,FRONTIER orbitals ,EXCITED states ,ALUMINUM forming ,ORGANIC acids - Abstract
Molecular and electronic structures of transoid and cisoid forms of oxodi(fluoroboron(III)) complex of phthalocyanine [O(FB)
2 Pc] in the ground and excited states were studied using DFT and TD DFT methods. The peculiarities of the electrochemical and spectral properties of the tetra-tert-butyl substituted complex existing in the transoid form in organic solvents and in acid medium were considered in comparison with 1:1 complexes formed by aluminum subgroup metals and boron(III) subphthalocyanine. Coordination of two boron atoms in the coordination cavity of the phthalocyanine macrocycle leads to its tetragonal distortion both in the cisoid and especially in the transoid forms and stabilizes the frontier π-molecular orbitals, especially the lowest unoccupied MO. This results in the bathochromic shift of the long-wave Q band and strongly facilitates the reduction of macrocycle occurring for the transoid form at −0.19 V versus Ag/AgCl in dimethylformamide (DMF). Spectrophotometric titration in CH2 Cl2 -CF3 COOH medium showed that the basicity of the meso-nitrogens is decreased upon coordination of two boron atoms. Slow deborylation can occur either in a strongly acid medium (96% H2 SO4 ) or in the presence of water in DMF. The absence of fluorescence and ability to generate singlet oxygen is explained by quenching of the excited state due to conformation flexibility of the macrocycle and inversion of the coordination center in the transoid form. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
38. Introductory Lectures on Higher-Spin Theories.
- Author
-
Fredenhagen, Stefan, Rahman, R., Taronna, M., Campoleoni, Andrea, Didenko, V. E., and Skvortsov, E. D.
- Published
- 2024
- Full Text
- View/download PDF
39. Non-Coagulant Spinning of High-Strength Fibers from Homopolymer Polyacrylonitrile Synthesized via Anionic Polymerisation.
- Author
-
Skvortsov, Ivan Yu., Kuzin, Mikhail S., Gerasimenko, Pavel S., Mironova, Maria V., Golubev, Yaroslav V., and Kulichikhin, Valery G.
- Subjects
POLYACRYLONITRILES ,ADDITION polymerization ,FIBERS ,FIBER orientation ,POLYMERIZATION ,LYOTROPIC liquid crystals ,RHEOLOGY ,CARBON fibers - Abstract
The rheological properties, spinnability, and thermal–oxidative stabilization of high-molecular-weight linear polyacrylonitrile (PAN) homopolymers (molecular weights M
η = 90–500 kg/mol), synthesized via a novel metal-free anionic polymerization method, were investigated to reduce coagulant use, enable solvent recycling, and increase the carbon yield of the resulting carbon fibers. This approach enabled the application of the mechanotropic (non-coagulating) spinning method for homopolymer PAN solutions in a wide range of molecular weights and demonstrated the possibility of achieving a high degree of fiber orientation and reasonable mechanical properties. Rheological analysis revealed a significant increase in solution elasticity (G′) with increasing molecular weight, facilitating the choice of optimal deformation rates for effective chain stretching prior to strain-induced phase separation during the eco-friendly spinning of concentrated solutions without using coagulation baths. The possibility of collecting ~80 wt% of the solvent at the first stage of spinning from the as-spun fibers was shown. Transparent, defect-free fibers with a tensile strength of up to 800 MPa and elongation at break of about 20% were spun. Thermal treatment up to 1500 °C yielded carbon fibers with a carbon residue of ~50 wt%, in contrast to ~35 wt% for industrial radically polymerized PAN carbonized under the same conditions. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
40. Effects of high-temperature annealing on vacancy complexes and luminescence properties in multilayer periodic structures with elastically strained GeSiSn layers.
- Author
-
Timofeev, Vyacheslav, Skvortsov, Ilya, Mashanov, Vladimir, Nikiforov, Alexandr, Kolyada, Dmitry, Firsov, Dmitry, Komkov, Oleg, Samadov, Samir, Sidorin, Alexey, and Orlov, Oleg
- Subjects
LUMINESCENCE ,POSITRON annihilation ,QUANTUM wells ,HETEROJUNCTIONS ,QUANTUM dots ,HYDROGEN plasmas ,HIGH temperatures - Abstract
Effects of postgrowth high-temperature annealing on vacancy complexes and photoluminescence (PL) from GeSiSn/Si multiple quantum wells (MQWs) are studied. The series of PL peaks related to the vacancy-tin complexes was observed for as-grown samples including different structures, such as GeSiSn/Si MQWs, multilayer periodic structure with GeSiSn quantum dots (QDs), GeSn cross-structures upon GeSiSn/Si MQWs, and thick GeSiSn layers. The PL band intensity is significantly reduced after annealing at 700 °C corresponding to the reduction in vacancy density, as demonstrated by the positron annihilation spectroscopy (PAS) data. Such annealing also results in the appearance of the PL signal related to the interband optical transitions in GeSiSn/Si MQWs. However, the high temperature could negatively impact the sharpness of heterointerfaces due to Sn diffusion, thus limiting the PL efficiency. To improve the luminescence properties of GeSiSn/Si structures, we proposed a two-stage technique combining both the annealing and subsequent treatment of samples in a hydrogen plasma at 200 °C. The plasma treatment significantly reduces the PL band of vacancy-related defects, whereas annealing at a moderate temperature of ∼600 °C prevents the blurring of heterointerfaces. As a result, we demonstrate an increase in the relative efficiency of interband PL of type II GeSiSn/Si MQW structures emitting in the range of 1.5–2 μm. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Strange higher-spin topological systems in 3D.
- Author
-
Boulanger, Nicolas, Campoleoni, Andrea, Lekeu, Victor, and Skvortsov, Evgeny
- Abstract
Motivated by the generation of action principles from off-shell dualisation, we present a general class of free, topological theories in three dimensional Minkowski spacetime that exhibit higher-spin gauge invariance. In the spin-two case, we recover a dual reformulation of the triplet system already known, while the higher-spin systems that we obtain seem to be new. They are associated with wild quivers. We study in which situations these exotic (or strange) higher-spin models can be extended to dS
3 and AdS3 backgrounds, revealing that the flat limit of such models, when they exist, admits a one-parameter freedom. Interactions are studied in the simplest higher-spin case featuring spin-2 and spin-3 fields. We then give several higher-spin generalizations of these strange systems. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
42. Study of the efficiency of using a machine in the automation of agricultural production.
- Author
-
Kokieva, Galiya, Skvortsov, Vadim, Belenkiy, Yury, Akhmetshin, Stanislav, Yumagulova, Venera, and Syromiatnykov, Yurii
- Published
- 2024
- Full Text
- View/download PDF
43. Dynamics of the transition resistance of Al–(Ti, Ni, Mo)–Si type contacts under conditions of non-stationary electrical loads.
- Author
-
Skvortsov, Arkadiy A., Koryachko, Marina V., Kuleshova, Svetlana I., and Rybakova, Margarita R.
- Subjects
ELECTRICAL load ,ELECTRIC currents ,OHMIC contacts ,QUALITY control ,SEMICONDUCTORS - Abstract
This paper analyses the behavioral features of ohmic contacts under the conditions of traditional isothermal annealing. The purpose of this paper is to study the value change of the semiconductor contact resistance when applying electric current pulses of different powers. For the experiments, structures were formed of metal-sublayer-semiconductor wafer Al–(Ti, Ni, Mo)–Si. The quality control of the deposited films was carried out microscopically by the four-probe method. The presented results indicate the solid-phase interaction of components during diffusion annealing Si–Me–Al thin-film systems. This rearrangement of atoms, which occurs with grain-boundary diffusion, significantly affects the electrical and thermal characteristics of the formed contacts. The novelty of the paper is that the optimal parameters of a rectangular current pulse were selected, which made it possible to reduce the value of the transition resistance by 1.6 times. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
44. Recent Advances in Superhydrophobic Materials Development for Maritime Applications.
- Author
-
Tang, Zhao Qing, Tian, Tongfei, Molino, Paul J., Skvortsov, Alex, Ruan, Dong, Ding, Jie, and Li, Yali
- Subjects
DRAG reduction ,MATERIALS science ,SUPERHYDROPHOBIC surfaces ,INTELLIGENT transportation systems ,CORROSION resistance ,MACHINE learning - Abstract
Underwater superhydrophobic surfaces stand as a promising frontier in materials science, holding immense potential for applications in underwater infrastructure, vehicles, pipelines, robots, and sensors. Despite this potential, widespread commercial adoption of these surfaces faces limitations, primarily rooted in challenges related to material durability and the stability of the air plastron during prolonged submersion. Factors such as pressure, flow, and temperature further complicate the operational viability of underwater superhydrophobic technology. This comprehensive review navigates the evolving landscape of underwater superhydrophobic technology, providing a deep dive into the introduction, advancements, and innovations in design, fabrication, and testing techniques. Recent breakthroughs in nanotechnology, magnetic‐responsive coatings, additive manufacturing, and machine learning are highlighted, showcasing the diverse avenues of progress. Notable research endeavors concentrate on enhancing the longevity of plastrons, the fundamental element governing superhydrophobic behavior. The review explores the multifaceted applications of superhydrophobic coatings in the underwater environment, encompassing areas such as drag reduction, anti‐biofouling, and corrosion resistance. A critical examination of commercial offerings in the superhydrophobic coating landscape offers a current perspective on available solutions. In conclusion, the review provides valuable insights and forward‐looking recommendations to propel the field of underwater superhydrophobicity toward new dimensions of innovation and practical utility. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Acoustic radiation from multilayered materials using the reciprocity principle.
- Author
-
MacGillivray, Ian and Skvortsov, Alex
- Subjects
ACOUSTIC radiation ,RECIPROCITY theorems ,ACOUSTIC radiation force ,SHEAR waves ,LONGITUDINAL waves ,REFLECTANCE ,ACOUSTIC streaming - Abstract
Application of the reciprocity principle to evaluate the acoustic radiation from arbitrary multilayered fluid and solid materials is described. To include the effect of shear motion in surrounding media, including viscosity in a fluid, equations for the acoustic radiation from such materials under point force excitation are developed in terms of reflection and transmission coefficients for longitudinal and shear waves. Calculations for forcing on either side of the layered material and in arbitrary directions, and for any asymmetric layer arrangements, are conducted. The frequency range of the calculations is not restricted by thin-plate or thick-plate theory. The test case for the radiation from plates embedded in a viscous and attenuating fluid has been investigated in detail. The effect of viscosity and attenuation has been quantified and shown to be significant at high frequencies. Application to the problem of flow noise is also briefly discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. On the Relation between Denjoy–Khintchine and -Integrals.
- Author
-
Skvortsov, V. A. and Sworowski, P.
- Subjects
INTEGRALS ,ARGUMENT - Abstract
We locate Musial and Sagher's concept of -integration within the approximate Henstock–Kurzweil integral theory. If we restrict the -integral by the requirement that the indefinite -integral is continuous, then it becomes included in the classical Denjoy–Khintchine integral. We provide a direct argument demonstrating that this inclusion is proper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. BRD2 and BRD3 genes independently evolved RNA structures to control unproductive splicing.
- Author
-
Petrova, Marina, Margasyuk, Sergey, Vorobeva, Margarita, Skvortsov, Dmitry, Dontsova, Olga A, and Pervouchine, Dmitri D
- Published
- 2024
- Full Text
- View/download PDF
48. The Influence of Plastic Deformation and Aging on the Amplitude Dependence of Internal Friction and the Structure of the ZA27 Damping Alloy.
- Author
-
Skvortsov, A. I., Mel'chakov, M. A., Sergeeva, A. V., and Kozlov, V. A.
- Abstract
The influence of the degree of plastic deformation at room temperature, followed by aging, on the amplitude dependence of internal friction and microstructure of the pre-hardened alloy ZA27 was investigated. The main structural mechanism affecting the amplitude dependence of internal friction under these treatments was analyzed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. A novel bioinformatic method for the identification of antimicrobial peptides in metagenomes.
- Author
-
Megaw, Julianne, Skvortsov, Timofey, Gori, Giulia, Dabai, Aliyu I, Gilmore, Brendan F, and Allen, Christopher C R
- Subjects
ANTIMICROBIAL peptides ,AMINO acid sequence ,PEPTIDE antibiotics ,PEPTIDES ,METAGENOMICS ,ETHANOL - Abstract
Aims This study aimed to develop a new bioinformatic approach for the identification of novel antimicrobial peptides (AMPs), which did not depend on sequence similarity to known AMPs held within databases, but on structural mimicry of another antimicrobial compound, in this case an ultrashort, synthetic, cationic lipopeptide (C
12- OOWW-NH2 ). Methods and results When applied to a collection of metagenomic datasets, our outlined bioinformatic method successfully identified several short (8–10aa) functional AMPs, the activity of which was verified via disk diffusion and minimum inhibitory concentration assays against a panel of 12 bacterial strains. Some peptides had activity comparable to, or in some cases, greater than, those from published studies that identified AMPs using more conventional methods. We also explored the effects of modifications, including extension of the peptides, observing an activity peak at 9–12aa. Additionally, the inclusion of a C-terminal amide enhanced activity in most cases. Our most promising candidate (named PB2-10aa-NH2 ) was thermally stable, lipid-soluble, and possessed synergistic activity with ethanol but not with a conventional antibiotic (streptomycin). Conclusions While several bioinformatic methods exist to predict AMPs, the approach outlined here is much simpler and can be used to quickly scan huge datasets. Searching for peptide sequences bearing structural similarity to other antimicrobial compounds may present a further opportunity to identify novel AMPs with clinical relevance, and provide a meaningful contribution to the pressing global issue of AMR. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
50. Remote Recognition of Materials Using Laser Photothermal Radiometry.
- Author
-
Abramov, P. I., Kuznetsov, E. V., Skvortsov, L. A., and Skvortsova, M. I.
- Subjects
INFRARED radiometry ,RADIOMETRY ,LASERS ,PULSED lasers ,WIND pressure ,SYNTHETIC products ,LASER spectroscopy - Abstract
The feasibility of recognizing opaque materials in remote objects using pulsed laser photothermal radiometry with prolonged pulsed exposure is examined. Theoretical calculations are given of the range of recognition of materials with laser activation of their surfaces. The computational results indicate a significant influence of thermal parameters on recognition range. It is shown experimentally that there is a reduction in the range by roughly an order of magnitude if the material of the search object has a large thermal inertia (metals) compared to a material with a low thermal inertia (polycarbonate, rubber), which provides a sufficient probability for their difference. Here a condition of strong surface absorption must hold at the laser wavelength. In the case of synthetic polymer products these conditions are met to the greatest extent by a CO
2 laser. The effect of wind load on the temperature of a laser spot on the object is one of the key conditions in this method. A way of reducing this effect to a minimum or even eliminating it nearly completely is proposed. Issues related to the feasibility of increasing the recognition range are discussed. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
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