Thermal Quenching of Intrinsic Photoluminescence in Amorphous and Monoclinic HfO Nanotubes.

Nanotubular hafnia arrays hold significant promise for advanced opto- and nanoelectronic applications. However, the known studies concern mostly the luminescent properties of doped HfO-based nanostructures, while the optical properties of nominally pure hafnia with optically active centers of intrinsic origin are far from being sufficiently investigated. In this work, for the first time we have conducted research on the wide-range temperature effects in the photoluminescence processes of anion-defective hafnia nanotubes with an amorphous and monoclinic structure, synthesized by the electrochemical oxidation method.

Viscous terahertz photoconductivity of hydrodynamic electrons in graphene.

Light incident upon materials can induce changes in their electrical conductivity, a phenomenon referred to as photoresistance. In semiconductors, the photoresistance is negative, as light-induced promotion of electrons across the bandgap enhances the number of charge carriers participating in transport. In superconductors and normal metals, the photoresistance is positive because of the destruction of the superconducting state and enhanced momentum-relaxing scattering, respectively.

Analysis of the Current State of Research on Bio-Healing Concrete (Bioconcrete).

The relatively small tensile strength of concrete makes this material particularly vulnerable to cracking. However, the reality is that it is not always possible and practically useful to conduct studies on high-quality sealing cracks due to their inaccessibility or small opening width. Despite the fact that currently there are many technologies for creating self-healing cement composites, one of the most popular is the technology for creating a biologically active self-healing mechanism for concrete.

High-Mobility Compensated Semimetals, Orbital Magnetization, and Umklapp Scattering in Bilayer Graphene Moiré Superlattices.

Twist-controlled moiré superlattices (MSs) have emerged as a versatile platform for realizing artificial systems with complex electronic spectra. The combination of Bernal-stacked bilayer graphene (BLG) and hexagonal boron nitride (hBN) can give rise to an interesting MS, which has recently featured a set of unexpected behaviors, such as unconventional ferroelectricity and the electronic ratchet effect. Yet, the understanding of the electronic properties of BLG/hBN MS has, at present, remained fairly limited.

Luminescence in Anion-Deficient Hafnia Nanotubes.

Hafnia-based nanostructures and other high-k dielectrics are promising wide-gap materials for developing new opto- and nanoelectronic devices. They possess a unique combination of physical and chemical properties, such as insensitivity to electrical and optical degradation, radiation damage stability, a high specific surface area, and an increased concentration of the appropriate active electron-hole centers. The present paper aims to investigate the structural, optical, and luminescent properties of anodized non-stoichiometric HfO nanotubes.

Randomized Clinical Trial of Hybrid vs. Surgical vs. Percutaneous Multivessel Coronary Revascularization: 5‑year Follow-up of HREVS Trial.

Aim      To evaluate 5-year results of the HREVS (Hybrid REvascularization Versus Standarts) study.Material and methods  The study included 155 consecutive patients with multivessel coronary artery disease who were randomized into 3 groups: coronary artery bypass grafting (CABG) (n=50), hybrid coronary revascularization (HCR) (n=52) and percutaneous coronary intervention (PCI) (n=53) according to the consensus of the cardiology team on the technical and clinical feasibility of each of the three coronary revascularization strategies. The primary endpoint of the study was residual ischemia 12 months after revascularization according to data of single-photon emission computed tomography (SPECT).

Upper Critical Field and Tunneling Spectroscopy of Underdoped Na(Fe,Co)As Single Crystals.

A comprehensive study of superconducting properties of underdoped NaFe0.979Co0.021As single crystals by a combination of upper critical field measurements and incoherent multiple Andreev reflection effect (IMARE) spectroscopy is presented.

[Latex Agglutination as an Alternative to the Hemagglutination Reaction of Influenza Viruses].

As an alternative to the classical method of erythrocyte hemagglutination, a latex agglutination assay based on the interaction of influenza viruses with the sialoglycoprotein fetuin immobilized on the surface of polystyrene microspheres has been developed. Twelve influenza A virus strains of different subtypes and two influenza B viruses of different lines were tested. Simultaneous titration of viruses using the classical hemagglutination test and the proposed latex agglutination assay showed similar sensitivity and a high degree of correlation (R = 0.

Alteration of Structure and Characteristics of Concrete with Coconut Shell as a Substitution of a Part of Coarse Aggregate.

One of the most promising ways to solve the problem of reducing the rate of depletion of natural non-renewable components of concrete is their complete or partial replacement with renewable plant counterparts that are industrial and agricultural waste. The research significance of this article lies in the determination at the micro- and macro-levels of the principles of the relationship between the composition, the process of structure formation and the formation of properties of concrete based on coconut shells (CSs), as well as the substantiation at the micro- and macro-levels of the effectiveness of such a solution from the point of view of fundamental and applied materials science. The aim of this study was to solve the problem of substantiating the feasibility of concrete consisting of a mineral cement-sand matrix and aggregate in the form of crushed CS, as well as finding a rational combination of components and studying the structure and characteristics of concrete.

Analytical Review of Geopolymer Concrete: Retrospective and Current Issues.

The concept of sustainable development provides for the search for environmentally friendly alternatives to traditional materials and technologies that would reduce the amount of CO emissions into the atmosphere, do not pollute the environment, and reduce energy costs and the cost of production processes. These technologies include the production of geopolymer concretes. The purpose of the study was a detailed in-depth analytical review of studies of the processes of structure formation and properties of geopolymer concretes in retrospect and the current state of the issue.

Combined Effect of Ceramic Waste Powder Additives and PVA on the Structure and Properties of Geopolymer Concrete Used for Finishing Facades of Buildings.

Currently, there is great interest in geopolymer composites as an alternative and environmentally friendly basis for compositions for restoring the facades of historical and modern buildings. Although the use of these compounds is much smaller than conventional concrete, replacing their main components with ecological geopolymer counterparts still has the potential to significantly reduce the carbon footprint and reduce the amount of greenhouse gas emitted into the atmosphere. The study aimed to obtain geopolymer concrete with improved physical, mechanical, and adhesive characteristics, designed to restore the finishing of building facades.

Effect of Walnut-Shell Additive on the Structure and Characteristics of Concrete.

The partial replacement of the mineral components of concrete with natural renewable analogues in full possession of the performance characteristics of the final material, allows not only the concrete-production process to be made more environmentally friendly and inexpensive, but also to solve an important task for the agricultural industry, which is that associated with waste disposal. The scientific novelty of the work is in the obtaining of new concrete compositions by the partial replacement of coarse aggregate with a natural analogue in the form of a walnut shell, which has the maximum ratio of the strength of the composite to its density, as well as in identifying new dependencies of strength and density and their ratio on the amount of replacement of mineral coarse-aggregate walnut shell. The main goal of this article was to analyze the effect of composition factors on characteristics of concrete with partial replacement of large aggregates with walnut shells and to search for the optimal compound that would make it possible to obtain concrete with a minimum decrease in strength characteristics with a maximum decrease in concrete density.

Strength of Compressed Reinforced Concrete Elements Reinforced with CFRP at Different Load Application Eccentricity.

Currently, many studies are devoted to the use of polymer composite materials to increase the strength and stability of concrete elements. In compressed reinforced concrete elements, the bearing capacity depends on the eccentricity of the external application of the external force and the corresponding stress-strain state, as well as the location and number of composite materials glued to the surface of the structure. The choice of a scheme for placing composite materials depending on the stress state of the structure is an urgent scientific problem.

Mass spectrometric study and modeling of the thermodynamic properties of SrO-Al O melts at high temperatures.

Rationale: The SrO-Al O system holds promise as a base for a wide spectrum of advanced materials, which may be synthesized or applied at high temperatures. Therefore, studying vaporization and high-temperature thermodynamic properties of this system is of great practical importance.

Methods: Samples of the SrO-Al O system were obtained by solid-state synthesis and identified by X-ray fluorescence analysis, X-ray phase analysis, scanning electron microscopy, electron probe microanalysis, simultaneous thermal analysis, and thermogravimetric analysis.

Phase Formation of Iron-Based Superconductors during Mechanical Alloying.

We successfully synthesized bulk BaNaFeAs and SrNaFeAs compounds by high-energy mechanical alloying (MA) technique. The MA process results in homogeneous amorphous phases of BaFeAs and SrFeAs. It was found that the optimum time for high-energy milling in all cases is about 1.

High-temperature mass spectrometric study and modeling of ceramics based on the Al O -SiO -ZrO system.

Rationale: Materials based on the Al O -SiO -ZrO system are promising for a wide range of high-temperature technological applications, such as thermal barrier coatings in the aviation and space industry or advanced materials in nuclear power reactors. Experimental studies of the ceramics based on this system by the Knudsen effusion mass spectrometric (KEMS) method are of significant interest in designing technological processes for the synthesis and exploitation of the Al O -SiO -ZrO materials.

Methods: Samples of ceramics in the Al O -SiO -ZrO system, including the Al O -ZrO and SiO -ZrO binaries, were prepared by solid-state synthesis.

[Correction of enteral distress syndrome in acute intestinal obstruction].

Objective: On the basis of a comprehensive assessment of the functional state of the intestine in acute mechanical small bowel obstruction, to justify adequate schemes of its protection.

Material And Methods: A clinical and laboratory study of 48 patients with acute small bowel obstruction developed against the background of abdominal adhesions, strangulated abdominal hernia was conducted. The first group (=25) of patients who underwent laparotomy, removal of intestinal obstruction (adhesiolysis and/or herniation, hernial gate plastic surgery), intestinal intubation, standardized therapy after surgery.

Numerical Simulation of the Bearing Capacity of Variotropic Short Concrete Beams Reinforced with Polymer Composite Reinforcing Bars.

One of the disadvantages of reinforced concrete is the large weight of structures due to the steel reinforcement. A way to overcome this issue and develop new types of reinforcing elements is by using polymer composite reinforcement, which can successfully compensate for the shortcomings of steel reinforcement. Additionally, a promising direction is the creation of variotropic (transversely isotropic) building elements.

High-temperature mass spectrometric study of thermodynamic properties in the TiO -Al O -SiO system and modeling.

Rationale: The TiO -Al O -SiO system is the base for various glass-ceramic materials, which have great practical value for a large number of modern technologies. Many TiO -Al O -SiO materials are synthesized or applied at high temperatures, which justifies the relevance of the present study.

Methods: The samples in the TiO -Al O -SiO system were synthesized using the method of induction melting in a cold crucible.

Mass spectrometric study and modeling of the thermodynamic properties in the Gd O -ZrO -HfO system at high temperatures.

Rationale: Materials based on the Gd O -ZrO -HfO system are promising for a wide range of high-temperature technological applications, such as for obtaining thermal barrier coatings in the aviation and space industry, as well as advanced materials in nuclear power applications. Experimental studies of the ceramics based on this system by the Knudsen effusion mass spectrometric method provides such valuable information as the vapor composition over the samples and enables derivation of the thermodynamic functions.

Methods: Samples of ceramics in the Gd O -ZrO -HfO system were synthesized and analyzed by X-ray fluorescence and diffraction techniques.

High-temperature mass spectrometric study of the thermodynamic properties in the Sm O -ZrO -HfO system.

Rationale: The Sm O -ZrO -HfO system is a promising base for the development of a wide spectrum of new refractory materials. Reliable data on thermodynamic properties in this system are of significant importance for planning the preparation and application of high-temperature ceramics. Especially, they can be useful for calculation of the unknown phase equilibria in this system.

Mechanism of Vascular Injury in Transcatheter Aortic Valve Replacement.

Unlabelled: was to determine the potential mechanism of vascular complications due to "catheter-vascular wall" interaction in transcatheter aortic valve replacement using experimental and numerical analysis.

Materials And Methods: A series of full-scale bench tests and numerical simulations were carried out using the CoreValve commercial transfemoral delivery system for aortic valve bioprosthesis (Medtronic Inc., USA).

Aortography Keypoint Tracking for Transcatheter Aortic Valve Implantation Based on Multi-Task Learning.

Currently, transcatheter aortic valve implantation (TAVI) represents the most efficient treatment option for patients with aortic stenosis, yet its clinical outcomes largely depend on the accuracy of valve positioning that is frequently complicated when routine imaging modalities are applied. Therefore, existing limitations of perioperative imaging underscore the need for the development of novel visual assistance systems enabling accurate procedures. In this paper, we propose an original multi-task learning-based algorithm for tracking the location of anatomical landmarks and labeling critical keypoints on both aortic valve and delivery system during TAVI.

Scale-Up of Biosynthesis Process of Bacterial Nanocellulose.

Bacterial nanocellulose (BNC) is a unique product of microbiological synthesis, having a lot of applications among which the most important is biomedicine. Objective complexities in scaling up the biosynthesis of BNC are associated with the nature of microbial producers for which BNC is not the target metabolite, therefore biosynthesis lasts long, with the BNC yield being small. Thus, the BNC scale-up problem has not yet been overcome.