Search

We report the results of core-shell (CdSe/CdS) quantum dots study. Quantum dots sizes were evaluated as 2.0 and 2.9 nm from absorbance edge position. We suggest two types of traps, predict properties of these traps based on upconversion luminescence data and previous studies of quantum dots (CdSe cores only) and bulk CdS.

The arc operating voltage and the mass/charge composition of the arc plasma were measured for W-fuzz samples with different fuzz thicknesses at different numbers of arc pulses. It was found that the formation of a fuzz structure led to a significant decrease in the arc operating voltage within the first few arc pulses. With an increase in the number of pulses, the operating voltage and the mean charge of tungsten ions in the arc plasma increased to values characteristic of conventional tungsten cathodes. The obtained experimental data were analyzed theoretically using an empirical cohesive energy rule and a magnetohydrodynamic model of the ionization processes occurring in a cathode plasma jet.

Chronic obstructive pulmonary disease is now one of the most common noncommunicable diseases and the main causes of morbidity, disability and mortality in the world. In recent years, new approaches to epidemiology, diagnosis, classification (categorization), evaluation of phenotypes, as well as characterization and assessment of the severity of сhronic obstructive pulmonary disease exacerbations have emerged. Modern approaches to starting and subsequent drug therapy have changed significantly. This is largely due to the results of recently conducted major clinical trials, demonstrated high efficacy of triple fixed combinations, including inhaled glucocorticosteroids, long-acting beta-agonists and long-acting anticholinergic drugs. The use of non-medication methods (smoking cessation, physical activity and respiratory rehabilitation) and modern approaches to the treatment of respiratory failure and antibiotic therapy remain important. In terms of their significance, all these updates have a significant impact on real clinical practice and can be considered as a novel paradigm of the approaches to the diagnosis and management of this disease.

Fibrosis is a dynamic process characterized by a typical cascade of events as a result of overexpressed repair of connective tissue in response to injury, and manifested by excessive accumulation of extracellular matrix. The development of fibrosis is a determining factor in the pathogenesis, clinical course and prognosis of many diseases, among which interstitial lung diseases occupy a special place. According to a large Russian registry (ClinicalTrials.gov: NCT04492384), in a third of patients with COVID-19, the volume of lung parenchyma involvement exceeds 50% (CT 3-4). The rapid growth in the number of patients who have had a coronavirus infection with lung damage has raised the issues of its long-term consequences to the number of the most relevant in internal medicine of the current time. Often, in the outcome of a coronavirus infection, patients retain clinical and functional changes that are similar to interstitial lung diseases of a different origin, the prognosis of which is determined by the development of interstitial fibrosis and the rate of its progression. This article is an attempt to consider topical issues of fibrogenesis in patients who have undergone a new coronavirus infection through the prism of polar data on immunobiology, clinical course and prognosis.

Hypersensitivity pneumonitis (HP) is a complex interstitial pulmonary syndrome. This clinical entity is characterized by sensitization to a specific antigen. Early detection of this antigen is associated with an increased likelihood of a favorable outcome. Increased mortality in hypersensitivity pneumonitis is associated with the development of lung fibrosis. At the same time, clinical interventions do not significantly improve the prognosis of the disease due to a lack of understanding the mechanisms underlying the development of this type of fibrosis. Using reliable biomarkers that objectively reflect biological processes in lung fibrosis may improve clinical decisionmaking. Various biomarkers are now beginning to play a critical role in diagnosing and treating a variety of human diseases. Unfortunately, hypersensitivity pneumonitis is an exception to this general trend. There is still a great deal of research to be done in this area in the search for diagnostic biomarkers. The aim of this study was to identify biomarkers of lung fibrosis development in patients with hypersensitivity pneumonitis. We used mature serum microRNAs, which may regulate inflammation and fibrosis, as such diagnostic markers. Patients with a diagnosis of hypersensitivity pneumonitis (with and without lung fibrosis) as well as healthy individuals without chronic diseases (control group) were included into the study. Clinical and laboratory parameters were assessed in all patients. The miScript miRNA PCR Array Kit (QIAGEN) was used for gene expression profiling of mature serum miRNAs. The data obtained were verified using real-time PCR. Our research has identified a number of mature microRNAs that are likely to be involved in lung fibrosis and inflammation (miR-22, miR-150 and miR-106b). Following an extended study, including monitoring of disease progression over time, the applied diagnostic kit may be used in clinical practice to determine disease activity and development of fibrosis formation in lung tissue in patients with different variants of hypersensitivity pneumonitis.

The paper presents the estimates for the possibility for large-scale production of 238Pu in the core of a VVER-1000 power reactor. The Np-fraction of minor actinides extracted from transuranic radioactive waste is proposed to be used as the starting material. The irradiation device with NpO2 fuel elements is installed at the reactor core center. The NpO2 fuel lattice pitch is varied and the irradiation device is surrounded by a heavy moderator layer to create the best possible spectral conditions for large-scale production (~ 3 kg/year) of conditioned plutonium with the required isotopic composition (not less than 85% of 238Pu and not more than 2 ppm of 236Pu). Plutonium with such isotopic composition can be used as the thermal source in thermoelectric radioisotope generators and in cardiac pacemakers. It has been demonstrated that the estimated scale of the 238Pu production in a VVER-type power reactor exceeds considerably the existing scale of its production in research reactors.

Aim. The primary aim of this study was to evaluate the pharmacokinetic parameters and confirm the bioequivalence of drugs containing gidazepam, namely Gidazepam® (Valenta Pharm, Russia) and Gidazepam VIC (VIVA Pharm, Republic of Kazakhstan), after a single administration of 1 tablet (50 mg) to healthy volunteers under fasting conditions. The secondary aim was a comparative analysis of safety profiles (adverse events) after a single administration of the studied drugs.Materials and methods. An open, randomized, crossover, two-period comparative study of pharmacokinetics and bioequivalence with adaptive design was conducted in healthy volunteers. Blood sampling was performed 15 minutes before and 20 min, 40 min, 1 h, 2 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 6 h, 8 h, 12 h, 24 h, 48 h, and 72 h after drug administration. High-performance liquid chromatography-tandem mass spectrometry was used for the evaluation of gidazepam and its metabolite (desalkylgidazepam) concentration with the subsequent calculation of pharmacokinetic parameters.Results. From both formulations, gidazepam was quickly absorbed and biotransformed into an active metabolite. Studied drugs had similar pharmacokinetic profiles, as 90% confidence intervals for the ratio of geometric means for Cmax and AUC(0-72) were within the bioequivalence acceptance range of 80.00–125.00 %. No adverse events were recorded as a result of clinical, laboratory or instrument evaluations during the study.Conclusion. Study drugs are considered bioequivalent and show comparable tolerability after a single administration under fasting conditions.

We report transient refractive index change in semiconductor nanoparticles dispersed in polymethylmethacrylate matrix via pump-probe experiment. At lower pump intensities the detected signal consists of the pulse autocorrelation-shaped part and another part delayed by 300 fs. The latter’s relative intensity depends on the pump level. However in CdS monocrystal the detected signal was found to lack this second feature completely.

We report the non-resonant excitation and probing of the nonlinear refractive index change in bulk semiconductors and semiconductor quantum dots through degenerate transient lens spectroscopy. The signal oscillates at the center laser field frequency, and the envelope of the former in quantum dots is distinctly different from the one in bulk sample. We discuss the applicability of this technique for polarization state probing in semiconductor media with femtosecond temporal resolution.

In this work we explored ultrafast molecular dynamics of liquids by the example of organic solvents. We used two pump pulses with orthogonal linear polarization for the separate measurement of the interaction induced response in liquids through optically-heterodyne detected optical-Kerr-effect (OHD-OKE). The pulse duration, the delay between pulses and the relation between the pump pulses amplitudes are the key parameters to manipulate inter- and intramolecular responses in OHD-OKE signal.

In July 2019, during the restoration of the building of the First Cadet Corps (the former mansion of Aleksandr D. Menshikov), fragments of two structures that differ in the degree of preservation – a cellar and an ice-house (lednik), dating back to the first half of the 18th century, were discovered. The lednik is a traditional building for the North-Western region of Russia and a rare wooden architectural object for St. Petersburg of that time. In order to prepare the construction for dismantling and to plan its further restoration, preliminary studies were conducted. It was found that details from other wooden objects, probably ships and barges, were used for this construction. The physical parameters of the wood of the structural parts varied. Most parts of the lednik are waterlogged. Based on the results of the research, a plan was worked out for the preservation of this unique historical architectural object.

Conventional chemotherapeutic approaches currently used for brain tumor treatment have low efficiency in targeted drug delivery and often have non-target toxicity. Development of stable and effective drug delivery vehicles for the most incurable diseases is one of the urgent biomedical challenges. We have developed polymer nanoparticles (NPs) with improved temozolomide (TMZ) delivery for promising brain tumor therapy, performing a rational design of polyelectrolyte complexes of oppositely charged polysaccharides of cationic chitosan and anionic pectin. The NPs’ diameter (30 to 330 nm) and zeta-potential (−29 to 73 mV) varied according to the initial mass ratios of the biopolymers. The evaluation of nanomechanical parameters of native NPs demonstrated changes in Young’s modulus from 58 to 234 kPa and adhesion from −0.3 to −3.57 pN. Possible mechanisms of NPs’ formation preliminary based on ionic interactions between ionogenic functional groups were proposed by IR spectroscopy and dynamic rheology. The study of the parameters and kinetics of TMZ sorption made it possible to identify compounds that most effectively immobilize and release the active substance in model liquids that simulate the internal environment of the body. A polyelectrolyte carrier based on an equal ratio of pectin–chitosan (0.1% by weight) was selected as the most effective for the delivery of TMZ among a series of obtained NPs, which indicates a promising approach to the treatment of brain tumors.

Impairment of higher mental functions can complicate the course of the postoperative period even after short and minimally invasive, including laparoscopic, surgical procedures. Postoperative cognitive dysfunction significantly challenges patients’ quality of life, negating real success of surgical intervention and anesthetic support. In some cases, early postoperative cognitive dysfunction may be one of the main predictors of persistent cognitive impairment.The purpose of the review. To contemplate etiology, pathogenesis and the current perspective of postoperative cognitive dysfunction.We analyzed 96 publications in various databases (PubMed, Medline, RSCI and others), including 67 papers published over the past 5 years.The review provides an overview of current definitions and classification of postoperative cognitive dysfunction, data on the prevalence, polyethyology and risk factors, potential impact of the type of anesthesia and surgical intervention on the development of postoperative cognitive dysfunction. Various pathogenetic mechanisms of higher mental functions impairment alongside with available effective pharmacotherapies to correct them were considered.Conclusion. Numerous adverse factors of the perioperative period, such as neurotoxic effects of general anesthetics, neuroinflammation in response to operational stress and surgical trauma, impaired autoregulation of the cerebral blood flow, imperfect oxygen homeostasis, interactions of neurotransmitter, etc., can potentially cause postoperative cognitive dysfunction. Further deeper insights into etiology and pathogenesis of early postoperative cognitive dysfunction are relevant and necessary to improve prevention strategies and identify most effective pharmacotherapies to correct such disorders.