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The spatial distribution of the components that make up the substitutional solid solution is non-uniform. The randomness of substitution leads to the formation of a random potential acting on secondary electrons in the conduction band and holes in the valence band. The random potential is one of the factors that significantly affect the migration, localization, and recombination of a given charge carriers. The influence of another factor, the energy structure of the conduction band, was considered for a substitutional solid solution of the AxB1−xC type in the model of multiple parabolic branches of the electron dispersion law. The transport mean free paths for the cases of elastic scattering of electrons by potential fluctuations and inelastic scattering of electrons by LA and LO phonons were calculated. It was shown that the presence of several parabolic branches of the electron dispersion law in the conduction band in all cases leads to a significant reduction in transport mean free paths compared to the model of one parabolic branch of the electron dispersion law in the conduction band.

The technological aspects of the light inorganic crystalline compounds suitable to create scintillation materials to detect charged particles and neutrons in a wide energy range have been examined. Among them, Li2CaSiO4:Eu was found to be a prospective candidate to control the valent state of the Rare Earth (RE) and to provide a high intensity of luminescence. It was demonstrated that the material has room for future improvement; however, this requires precise engineering of its composition—an experimental search of compositions or additives that will provide the maximum Eu2+/Eu3+ ratio to achieve a high scintillation light yield. The benefits of light inorganic materials are disclosed through the modeling of the linear density of nonequilibrium carriers along secondary particle tracks created in scintillators utilized for neutron detection. It is shown that oxide matrices have a larger linear density in comparison with halide crystalline compounds under alpha-particles and tritons, whereas light oxides can provide smaller numbers under protons.

Tightly focused 515-nm, 0.3-ps laser pulses modify in a laser filamentation regime the crystalline structure of an Ib-type high-pressure, high-temperature (HPHT) synthesized diamond in a thin-plate form. The modified microregions (micromarks) in the yellow and colorless crystal zones, possessing different concentrations of elementary substitutional nitrogen (N) impurity atoms (C-centers), exhibit their strongly diminished local IR absorption (upon correction to the thickness scaling factor). Simultaneously, local visible-range (400–550 nm) absorption coefficients were increased, and photoluminescence (PL) yield was strongly enhanced in the broad range of 450–800 nm. The strong yellow-red PL enhancement saturates with laser exposure, implying the complete conversion of C-centers into nitrogen-vacancy (NV0,−) ones due to the laser-induced generation of Frenkel “interstitial-vacancy” I–V carbon pairs. The other emerging blue-green (>470 nm) and green-yellow (>500 nm) PL bands were also simultaneously saturated versus the laser exposure. The observed IR/optical absorption and PL spectral changes enlighten the ultrashort pulse laser inscription of NV0−-based quantum-emitter centers in synthetic diamonds and enable the evaluation of the productivity of their inscription along with the corresponding I–V generation rates.

The growing demand for cheap, safe, recyclable, and environmentally friendly batteries highlights the importance of the development of organic electrode materials. Here, we present a novel redox-active polymer comprising a polyaniline-type conjugated backbone and quinizarin and anthraquinone units. The synthesized polymer was explored as a cathode material for batteries, and it delivered promising performance characteristics in both lithium and potassium cells. Excellent lithiation efficiency enabled high discharge capacity values of >400 mA g−1 in combination with good stability upon charge–discharge cycling. Similarly, the potassium cells with the polymer-based cathodes demonstrated a high discharge capacity of >200 mAh g−1 at 50 mA g−1 and impressive stability: no capacity deterioration was observed for over 3000 cycles at 11 A g−1, which was among the best results reported for K ion battery cathodes to date. The synthetic availability and low projected cost of the designed material paves a way to its practical implementation in scalable and inexpensive organic batteries, which are emerging as a sustainable energy storage technology.

The luminescent Z-scan technique with time resolution is applied to the study of the luminescence properties of CH3NH3PbBr3 single crystals representative of the family of hybrid organic–inorganic lead perovskites successfully applied recently in photovoltaics and currently investigated as potential nanosecond scintillators. The third harmonic of Ti-sapphire laser (λ = 266 nm) with a pulse duration of 26 fs and 1 kHz frequency was applied for the luminescence excitation creating the charge carriers with the estimated density from 1017 to 1021 cm−3 in the temperature range from 13 to 300 K. Temperature and excitation density dependence of the luminescence yield and kinetics is interpreted with the consideration of the temperature-dependent binding of electrons and holes into excitons, a saturation of defects responsible for the non-radiative relaxation channel competing with exciton creation; absorption saturation resulting in the increased penetration depth of the excitation radiation and hence the increased contribution of the re-absorption.

Two series of (Gd, Y, Yb)3Al2Ga3O12 quintuple compounds with a garnet structure and solely doped with Ce and Tb were prepared in the form of ceramics by sintering in oxygen at 1600 °C for two hours and studied for the interaction of activator ions with ytterbium ions entering the matrix. It was shown that the photoluminescence and scintillation of Ce3+ ions are completely suppressed, predominantly by tunneling ionization through the charge transfer state (CTS) of the Ce4+-Yb2+ ions. The photoluminescence of Tb3+ ions is quenched in the presence of ytterbium, but not completely due to the poor resonance conditions of Tb3+ intraconfiguration transitions and the CTS of the single Yb3+ and the CTS of Ce4+-Yb2+ ions. The scintillation in the visible range of both Ce3+- and Tb3+-doped samples is intensely quenched as well, which indicates strong competition from Yb3+ ions to activators in interaction with the Gd substrate.

The subject matter of the reported work refers to studying the interactions followed by the excited-state generation, which are chemical models of oxidative processes leading to a weak light emission emerging from living cells, and to explore the possibilities of using them as tools for evaluating the activity of oxygen-metabolism modulators, most prominently, natural bioantioxidants of biomedical value in particular. Methodologically, major attention is paid to analyzing the shapes of the time profiles of the light emission derived from a model sensory system in the presence of lipid samples of vegetable and animal (fish) origin rich in bioantioxidants. As a result, a modified reaction mechanism involving 12 elementary steps is proposed to rationalize the light-emission kinetics in the presence of natural bioantioxidants. We conclude that free radicals formed from bioantioxidants and their dimerization products contribute significantly to the general antiradical activity of lipid samples, which should be taken into account in developing efficient bioantioxidant assays for biomedical applications and while establishing the mechanisms of bioantioxidant effects on metabolic processes in vivo.

The development of sulfur-containing pharmaceutical compounds is important in the advancement of medicinal chemistry. Photosensitizers (PS) that acquire new properties upon incorporation of sulfur-containing groups or individual sulfur atoms into their structure are not neglected, either. In this work, a synthesis of sulfur-containing derivatives of natural chlorophyll a using Lawesson’s reagent was optimized. Thiocarbonyl chlorins were shown to have a significant bathochromic shift in the absorption and fluorescence bands. The feasibility of functionalizing the thiocarbonyl group at the macrocycle periphery by formation of a Pt(II) metal complex in the chemotherapeutic agent cisplatin was shown. The chemical stability of the resulting conjugate in aqueous solution was studied, and it was found to possess a high cytotoxic activity against sarcoma S37 tumor cells that results from the combined photodynamic and chemotherapeutic effect on these cells.

Background. Changes in the vascular wall, in particular, an increase in its stiffness and an increase in pressure in the aorta, as well as hypertrophy of the left ventricular myocardium are factors that determine a poor prognosis in patients with arterial hypertension. At the same time, the peculiarities of changes in arterial stiffness indices and left ventricular myocardial remodeling in patients with different sensitivity to salt loading have not been adequately studied. Aim. To conduct a comparative analysis of the values of peripheral blood pressure and central aortic pressure, indicators of left ventricular myocardial remodeling in salt-sensitive and salt-resistant patients with arterial hypertension. Materials and methods. The study involved 180 patients with arterial hypertension: 96 men and 84 women. The median age was 59 years. Salt sensitivity test was performed according to V.I. Kharchenko. All patients underwent 24-hour blood pressure monitoring, echocardiography. Indicators of peripheral arterial pressure and central aortic pressure, remodeling of the left ventricular myocardium were determined. Results. According to the results of the test V.I. Kharchenko, 88 patients were classified as salt-sensitive, 92 as salt-resistant. After a salt sensitivity test in salt-sensitive patients, the main indicators of peripheral blood pressure and central aortic pressure exceeded those in salt-resistant patients in the daytime, at night, and throughout the day as a whole. In the group of salt-sensitive individuals, statistically more significant negative changes in echocardiographic parameters were recorded; a significant number of salt-sensitive patients were diagnosed with prognostically unfavorable variants of left ventricular myocardial remodeling. Conclusion. In salt-sensitive patients with arterial hypertension, compared with salt-resistant patients, there are higher values of both peripheral blood pressure and central aortic pressure, more significant negative changes in echocardiographic parameters with the formation of concentric hypertrophy and eccentric remodeling of the left ventricular myocardium. It can be assumed that the assessment of salt sensitivity makes it possible to verify patients with the most unfavorable changes in parameters of ambulatory blood pressure monitoring and significant remodeling of the left ventricular myocardium. This approach can be used to individualize pharmacotherapy in patients with arterial hypertension and increase its effectiveness.

Background: Numerous studies have shown an effect of rapidly spreading SARS-COV-2 on combined anxiety-depressive disorders and maladjustment syndrome occurrences. Objective: To determine the primary medical students’ reactive anxiety level and the final scores of their educational progress in distance learning during the SARS-COV-2 pandemic. Materials and Methods: The study involved 824 students at medical universities in Saratov and Moscow. The assessment of the reactive anxiety level was carried out according to the State-Trait Anxiety Inventory, STAI; the average score of students' academic performance was calculated according to the data of the technological platform "1C: Enterprise" version 8.4.1. The survey was completed during distance learning in May 2020. The quality of distance learning was compared to a similar score for 2019, when students were trained in a traditional way. Statistical analysis was conducted using Statistica 6.0. Results: It was shown the presence of moderately severe disorders among the primary medical students according to the average score of reactive anxiety (43.28 ± 12.85), that expressed more in females s (p0.05) but the practical skills suffered much especially in time trend (p

Despite the clinical acceptance of ToF-PET, there is still a gap between the technology's performance and the end-user's needs. Core to bridging this gap is the ability to develop radiation detectors combining a short attenuation length and a sub-nanosecond time response. Currently, the detector of choice, Lu2SiO5:Ce3+ single crystal, is not selected for its ability to answer the performance needs, but as a trade-off between requirements and availability. To bypass the current performance limitations, in particular restricted time response, the concept of the heterostructured detector has been proposed. The concept aims at splitting the scintillation mechanisms across two materials, one acting primarily as an absorber and one as an ultra-fast emitter. If the concept has attracted the interest of the medical and material communities, little has been shown in terms of the benefits/limitations of the approach. Based on Monte Carlo simulations, we present a survey of heterostructure performance versus detector design. The data allow for a clear understanding of the design/performance relationship. This, in turn, enables the establishment of design rules toward the development and optimization of heterostructured detectors that could supersede the current detector technology in the medical imaging field but also across multiple sectors (e.g. high-energy physics, security).

Background. An elevated or inadequate sensitivity to salt intake is an important mechanism for maintaining high blood pressure in patients with arterial hypertension. Chronopharmacotherapy comprises an important approach to control arterial hypertension through personalised correction of blood pressure but requires a further proof of efficacy in salt-sensitive hypertensive patients.Objectives. An assessment of six-month dynamics of diurnal and nocturnal peripheral and central blood pressure in salt-sensitive patients with arterial hypertension under chronopharmacothe­rapy.Methods. A controlled randomised trial included 86 salt-sensitive patients with arterial hypertension. Salt sensitivity was estimated with a Kharchenko’s test. All patients had circadian monitoring of the peripheral and central blood pressure and glomerular filtration rate at baseline and in a six-month follow-up. The patients were randomised into 3 cohorts. Cohort A united patients received perindopril and amlodipine in morning, cohort B — perindopril in morning, amlodipine in evening, cohort C — perindopril in evening, amlodipine in morning. Statistica 12 (StatSoftInc, USA) was used for nonparametric statistical analyses.Results. In six months of chronopharmacotherapy a target arterial pressure was registered in 87.5% patients in cohort A, 96.4 and 96.2% patients in cohorts B and C, respectively. All cohorts exhibited a declining peripheral and central blood pressure over therapy. Cohort A had a greater decline in daytime, and cohorts B and C — both diurnally and nocturnally. Cohorts B and C had more patients with an adequate nocturnal blood pressure decline. Glomerular filtration rate also elevated with perindopril or amlodipine intake before bedtime.Conclusion. The perindopril or amlodipine intake before bedtime in a combined therapy for arterial hypertension provided for a target blood pressure in the overall majority of patients, effectively reduced peripheral and central blood pressure at all time intervals, contributed to optimising the circadian blood pressure profile and increased the glomerular filtration rate.

Semiconductor devices of quantum electronics based on InP/GaInAsP heterostructures require the creation of non-defective chips for emitting devices and photodetectors. The production of such chips is impossible without a thorough technological study of the growth processes of epitaxial structures. One of the important problems in relation to the growth of such structures is the growth defects associated with the process of dissociation of indium phosphide on the surface during their growth. The aim of the work was the investigation of the process and mechanism of destruction (dissociation) of the surface of indium phosphide substrates in the range of growth temperatures of structures, as well as the study of methods and techniques that allow minimize the process of dissociation of surface of indium phosphide. The work provides studies of the growth processes of InP/GaInAsP heterostructures, from the liquid phase, taking into account the degradation processes of the growth surface and the mechanisms for the formation of dissociation defects. The schemes of the dissociation process of the InP on the surface of the substrate and the formation of the defective surface of the substrate were analysed. At the same time, technological methods allowing to minimize the dissociation of the surface compound during the process of liquid-phase epitaxy were shown. The original design of a graphite cassette allowing to minimize the dissociation of the indium phosphide substrate in the process of liquid-phase epitaxy was proposed

During the last few years, in the territory of the Russian Federation, the number of cases of toxic phosphoric osteonecrosis of the jaws has increased against the background of taking drugs of “artisanal” production (pervitin, desomorphin). The aim of our study was to increase the effectiveness of surgical treatment of patients with a diagnosis of toxic phosphorus necrosis of the maxilla. We performed a comprehensive treatment of patients with a history of drug addiction and the above diagnosis. Surgical intervention in the volume of complete resection of pathologically altered tissues and reconstructive techniques using local tissues and a replaced flap made it possible to achieve good aesthetic and functional results in the early and late postoperative period. Thus, our proposed method of surgical treatment can be used in similar clinical situations.

GYAGG:Tb (Ce) scintillators have been confirmed to be promising sources of light emission when excited by an intense 150 keV electron beam. The saturation of the scintillation yield under such excitation conditions has been studied. To explain the results obtained, a model that considers the Auger quenching mechanism was used. The Ce-doped material did not show saturation, whereas a moderate 30% drop of the yield was measured in the Tb-doped sample at the highest excitation beam intensity ~1 A/cm2. This put forward a way to exploit the Tb-doped scintillator for indirect β-voltaic batteries.

In surgical dentistry, suture material is the only foreign body that remains in the tissues after surgery, and it can lead to several negative reactions, for example, infection of the wound. The purpose of this study was to compare the mechanical properties and microbiological resistance of mono- and polyfilament suture materials used in tooth extraction operations. The study of elongation and knot force was carried out on an Instron 5969 Dual Column Testing System device. The capillarity of the materials was studied on a setup assembled by the authors manually by immersing the ends of the filaments in a colored manganese solution. A microbiological study was carried out on the threads taken for the experiment immediately after wound suturing, and on day 7, at which time they were removed. The comparison was made according to Rothia mucilaginosa, Streptococcus sanguinis, Staphylococcus epidermidis. Results: monofilament suture materials (Prolene and Glycolon), after calculating the Kruskal–Wallis and Mann–Whitney indices, showed better performance in all experiments compared to polyfilament sutures (Vicryl and PGA). In capillarity comparison, there was a significant difference between groups (p = 0.00018). According to the sum of the results of three microbiological studies on day 7, monofilament suture materials absorbed less of the studied bacteria on their surface compared to the polyfilament ones (p < 0.05). Conclusions: Of the studied suture materials, Prolene had the best microbiological resistance and good mechanical properties.