Wear Resistance of Ti-6Al-4V Alloy Ball Heads for Use in Implants.

The effect of thermohydrogen treatment and vacuum ion-plasma nitriding on the determination of the volume and surface structure of ball heads made of Ti-6Al-4V alloy was studied. It was found that the submicrocrystalline structure formed in the head during thermohydrogen treatment makes it possible to achieve hardness values of 39-41 units HRC and a surface roughness of 0.02 μm.

Prospects for Psychological Support in Interplanetary Expeditions.

The article gives an overview of Russian experience in psychological support for orbital space flights. It describes procedures that currently exist and may possibly be used in upcoming manned interplanetary flights. The article also considers psychological unfavorable factors of autonomous interplanetary flights, as well as countermeasures, including promising methods of psychological support.

Oxidation Resistance of a Si-TiSi-MoSi-TiB-CaSi Coating on a C/C-SiC Substrate in High-Speed High-Enthalpy Air Plasma Flows.

The results of a study on the development and testing of a heat-resistant coating in a Si-TiSi-MoSi-TiB-CaSi system to protect C/C-SiC composites from oxidation and erosional entrainment in high-speed flows are presented here. The coating was formed using firing fusion technology on the powder composition. Oxidation resistance tests were carried out under static conditions in air at 1650 °C and under conditions of interaction with high-speed air plasma flows, with Mach numbers M = 5.

Polysaccharides as Stabilizers for Polymeric Microcarriers Fabrication.

Biodegradable polymeric microparticles are widely used in drug delivery systems with prolonged-release profiles and/or cell microcarriers. Their fabrication via the oil/water emulsion solvent evaporation technique has normally required emulsifiers in the aqueous phase. The present work aims to evaluate the effectiveness of various polysaccharides, such as chitosan, hyaluronic acid, cellulose, arabinogalactan, guar and their derivatives, as an alternative to synthetic surfactants for polylactide microparticle stabilization during their fabrication.

General Non-Markovian Quantum Dynamics.

A general approach to the construction of non-Markovian quantum theory is proposed. Non-Markovian equations for quantum observables and states are suggested by using general fractional calculus. In the proposed approach, the non-locality in time is represented by operator kernels of the Sonin type.

Public opinion as a means of managing social processes.

The relevance of the study is expressed by the improvement and development of tools for managing social processes and public procedures. There are a large number of concepts and theories that explain certain aspects of public opinion: exposure to influence, an impact on people's actions, and its contradictory nature. The main forming factors of individual behavior are the stereotypes and values that are developed within society.

Distance learning impact on the English language teaching during COVID-19.

These days, distance learning has almost completely replaced traditional teaching methods due to the COVID-19 pandemic and the introduction of quarantine measures. A sharp rise in interest in distance learning methodology has raised a number of new questions and challenges. This research examines changes in the training process and cognitive abilities and academic performance during the coronavirus pandemic.

Fabrication, Microstructure and Colloidal Stability of Humic Acids Loaded FeO/APTES Nanosorbents for Environmental Applications.

Nowadays, numerous researches are being performed to formulate nontoxic multifunctional magnetic materials possessing both high colloidal stability and magnetization, but there is a demand in the prediction of chemical and colloidal stability in water solutions. Herein, a series of silica-coated magnetite nanoparticles (MNPs) has been synthesized via the sol-gel method with and without establishing an inert atmosphere, and then it was tested in terms of humic acids (HA) loading applied as a multifunctional coating agent. The influence of ambient conditions on the microstructure, colloidal stability and HA loading of different silica-coated MNPs has been established.

Novel Self-Healing Metallocopolymers with Pendent 4-Phenyl-2,2':6',2″-terpyridine Ligand: Kinetic Studies and Mechanical Properties.

We report here our successful attempt to obtain self-healing supramolecular hydrogels with new metal-containing monomers (MCMs) with pendent 4-phenyl-2,2':6',2″-terpyridine metal complexes as reversible moieties by free radical copolymerization of MCMs with vinyl monomers, such as acrylic acid and acrylamide. The resulting metal-polymer hydrogels demonstrate a developed system of hydrogen, coordination and electron-complementary π-π stacking interactions, which play a critical role in achieving self-healing. Kinetic data show that the addition of a third metal-containing comonomer to the system decreases the initial polymerization rate, which is due to the specific effect of the metal group located in close proximity of the active center on the growth of radicals.

Quantum Maps with Memory from Generalized Lindblad Equation.

In this paper, we proposed the exactly solvable model of non-Markovian dynamics of open quantum systems. This model describes open quantum systems with memory and periodic sequence of kicks by environment. To describe these systems, the Lindblad equation for quantum observable is generalized by taking into account power-law fading memory.

Retrospective analysis of sleep patterns in patients with chronic disorders of consciousness.

Analysis of sleep patterns in patients with chronic disorders of consciousness attracts attention from the perspective of the diagnosis and prognosis of the disease as well as the treatment. Yet, the very existence of normal sleep in patients in a vegetative or minimally conscious state is still a matter of debate. This paper presents a retrospective analysis of overnight polysomnographic records of 40 patients with chronic disorders of consciousness aimed at the possibility of establishing the connection between the degree of impaired consciousness and the presence and organization of polysomnographic graphical elements, associated with stages of sleep in normal individuals.

Characterization of High-Temperature Superconductor Bulks for Electrical Machine Application.

High-temperature superconducting (HTS) bulks can be used in electrical applications. Experimental characterization of large-size HTS bulks is a tricky issue. The relevant parameters for their application were directly measured in this study.

[Computed tomography for assessment of postoperative outcomes in patients with parastomal hernia].

Objective: To show the efficacy of innovative hybrid intraperitoneal alloplasty in patients with parastomal hernia.

Material And Methods: Treatment outcomes were assessed in 60 patients with parastomal hernia using computed tomography.

Conclusion: The innovative hybrid intraperitoneal alloplasty reduces the risk of recurrence by 7 times (=0.

Basic Approaches to the Design of Intrinsic Self-Healing Polymers for Triboelectric Nanogenerators.

Triboelectric nanogenerators (TENGs) as a revolutionary system for harvesting mechanical energy have demonstrated high vitality and great advantage, which open up great prospects for their application in various areas of the society of the future. The past few years have seen exponential growth in many new classes of self-healing polymers (SHPs) for TENGs. This review presents and evaluates the SHP range for TENGs, and also attempts to assess the impact of modern polymer chemistry on the development of advanced materials for TENGs.

Effects of Humic Acids on the Ecotoxicity of FeO Nanoparticles and Fe-Ions: Impact of Oxidation and Aging.

The magnetite nanoparticles (MNPs) are increasingly produced and studied for various environmental applications, yet the information on their ecotoxicity is scarce. We evaluated the ecotoxicity of MNPs (~7 nm) before and after the addition of humic acids (HAs). White mustard and unicellular ciliates were used as test species.

Effects of Modified Magnetite Nanoparticles on Bacterial Cells and Enzyme Reactions.

Current paper presents biological effects of magnetite nanoparticles (MNPs). "Relations of MNP' characteristics (zeta-potential and hydrodynamic diameters) with effects on bacteria and their enzymatic reactions were the main focus.".

Long-term biventricular support following myocardial infarction from anterior descending coronary artery damage due to stabbing: A case report.

Background: The use of dual continuous-flow assist devices for biventricular support remains novel with only small case series or reports documenting outcomes.

Methods: We describe a 21-year-old woman suffered stabbing with damage of coronary artery with subsequent myocardial infarction and severe postinfarction heart failure with impaired right ventricular function. The patient underwent implantation of two continuous-flow ventricular assist devices.

Properties of Dicationic Disiloxane Ionic Liquids.

A number of dicationic ionic liquids with a disiloxane linker between imidazolium cations and bis(trifluoromethylsulfonyl)imide anion were synthesized and characterized. Melting points, viscosity, and volatility in a vacuum were measured; the thermal and hydrolytic stability of ionic liquids were also studied. The dependence of the properties on the structure of substituents in the cation of the ionic liquid was demonstrated.

Synthesis of Copper(II) Trimesinate Coordination Polymer and Its Use as a Sorbent for Organic Dyes and a Precursor for Nanostructured Material.

Several important synthesis pathways for metal-organic frameworks (MOFs) were applied to determine how the synthesis methods and conditions affect the structure and adsorption capacity of the resulting samples. In the present work, three different synthesis routes were used to obtain copper trimesinate coordination polymer: Slow evaporation (A), solvothermal synthesis using a polyethylene glycol (PEG-1500) modulator (B), and green synthesis in water (C). This MOF was characterized by elemental analysis, infrared spectrometry, X-ray diffraction, scanning electron microscopy, thermogravimetry and volumetric nitrogen adsorption/desorption.

Recent advances in metallopolymer-based drug delivery systems.

Metallopolymers (MPs) or metal-containing polymers have shown great potential as new drug delivery systems (DDSs) due to their unique properties, including universal architectures, composition, properties and surface chemistry. Over the past few decades, the exponential growth of many new classes of MPs that deal with these issues has been demonstrated. This review presents and assesses the recent advances and challenges associated with using MPs as DDSs.

Note: Additionally refined new possibilities of plasma probe diagnostics.

In two previous Notes published in this journal, a method of measuring probe sheath thickness and ion mass was described using Langmuir probe diagnostics in low pressure xenon plasma close to Maxwellian substance. According to the first Note, this method includes two stages: (i) in a special experiment with known ion mass, the Bohm and Child-Langmuir-Boguslavsky (CLB) equations for cylindrical Langmuir probes used in this xenon plasma were solved jointly to determine the probe sheath thicknesses and Bohm coefficient C ≈ 1.13; and (ii) in a general experiment, with known C, the same equations could be solved to obtain the probe sheath thicknesses and the mean ion mass.

Radio frequency source of a weakly expanding wedge-shaped xenon ion beam for contactless removal of large-sized space debris objects.

A theoretical-experimental research has been carried out to determine the characteristics of a radio frequency (RF) ion source for the generation of a weakly expanding wedge-shaped xenon ion beam. Such ion beam geometry is of interest as a prototype of an on-board ion injector for contactless "ion shepherding" by service spacecraft to remove large space debris objects from geostationary orbits. The wedge shape of the ion beam increases its range.

Colonization by Staphylococcus aureus of Nano-Structured Fluorinated Surfaces, Formed by Different Methods of Ion-Plasma Technology.

Colonization of fluorinated surfaces produced by ion-plasma technology by Staphylococcus aureus was studied by scanning electron microscopy and surface energy analysis. It was shown that the intensity of colonization was determined by the surface relief and fluorine content. Formation of nanostructured surfaces accompanied by a sharp decrease in the surface energy prevented adhesion of Staphylococcus aureus cells to the fluorine-containing surface.

Note: Refined possibilities for plasma probe diagnostics.

In an earlier publication, the ion mass determination technique was proposed using the Langmuir probe measurement results for low-pressure Maxwellian plasmas and their analysis, based on the Bohm effect and the Child-Boguslavsky-Langmuir (CBL) probe sheath model, allowing for probe sheath thickness and ion mass evaluations after the Bohm coefficient CBCyl ≈ 1.13 for cylindrical probes had been determined. In the present study, the step-front sheath model, being physically closer to the reality of gas discharge plasmas, was considered in order to correct the CBL sheath model results.

Note: The expansion of possibilities for plasma probe diagnostics.

The determination of ion mass for low-pressure Maxwellian plasmas has been proposed. It can be done using Langmuir probe measurements and the Bohm formula for the ion current density to a floating probe, due to this formula's reliance on ion mass. This goal was achieved by accurate measurements of xenon plasma parameters in the inductive discharge at pressure p = 2 ⋅ 10(-3) Torr using the Plasma Sensors VGPS-12 probe station with the cylindrical Langmuir probes.