Publications by authors named "SV Kravchenko"

The RNA-binding S1 domain is a β-barrel with a highly conserved RNA-binding site on its surface. This domain is an important part of the structures of different bacterial, archaeal, and eukaryotic proteins. A distinctive feature of the S1 domain is multiple presences (structural repeats) in proteins and protein complexes.

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The escalating threat of multidrug-resistant pathogens necessitates innovative approaches to combat infectious diseases. In this study, we examined peptides R23F*, V31K*, and R44K*, which were engineered to include an amyloidogenic fragment sourced from the S1 protein of , along with one or two cell-penetrating peptide (CPP) components. We assessed the antimicrobial efficacy of these peptides in a liquid medium against various strains of both Gram-positive bacteria, including (209P and 129B strains), MRSA (SA 180 and ATCC 43300 strains), and (strain IP 5832), and Gram-negative bacteria such as (ATCC 28753 and 2943 strains) and (MG1655 and K12 strains).

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The quantum phase transition observed experimentally in two-dimensional (2D) electron systems has been a subject of theoretical and experimental studies for almost 30 years. We suggest Gaussian approximation to the mean-field theory of the second-order phase transition to explain the experimental data. Our approach explains self-consistently the universal value of the critical exponent 3/2 (found after scaling measured resistivities on both sides of the transition as a function of temperature) as the result of the divergence of the correlation length when the electron density approaches the critical value.

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Combining antimicrobial peptides (AMPs) with cell-penetrating peptides (CPPs) has shown promise in boosting antimicrobial potency, especially against Gram-negative bacteria. We examined the CPP-AMP interaction with distinct bacterial types based on cell wall differences. Our investigation focused on AMPs incorporating penetratin CPP and dihybrid peptides containing both cell-penetrating TAT protein fragments from the human immunodeficiency virus and Antennapedia peptide (Antp).

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Bioprinting allows additive fabrication of bioengineered constructs with defined two- or three-dimensional organization using live cells, biopolymers and other materials. This article reviews main bioprinting technologies and their capabilities in clinical and experimental ophthalmology. Analysis of literature sources helped reveal and describe the main types of bioprinting technologies: inkjet, laser-assisted, and extrusion.

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The effective mass at the Fermi level is measured in the strongly interacting two-dimensional (2D) electron system in ultra-clean SiGe/Si/SiGe quantum wells in the low-temperature limit in tilted magnetic fields. At low electron densities, the effective mass is found to be strongly enhanced and independent of the degree of spin polarization, which indicates that the mass enhancement is not related to the electrons' spins. The observed effect turns out to be universal for silicon-based 2D electron systems, regardless of random potential, and cannot be explained by existing theories.

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The study aimed to investigate the effects of gliotoxin (GTX), a secondary fungal metabolite belonging to the epipolythiodioxopiperazines class, on Gram-positive and Gram-negative bacteria. While the cytotoxic mechanism of GTX on eukaryotes is well understood, its interaction with bacteria is not yet fully comprehended. The study discovered that S.

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Article Synopsis
  • - Organ-on-chip technology is a microfluidic device that mimics organ functions, allowing for accurate modeling of physiological processes, particularly in ophthalmology.
  • - It can model various eye conditions, such as dry eye syndrome and age-related macular degeneration, which aids in understanding disease mechanisms and testing new treatments.
  • - This technology enhances research efficiency by reducing costs and experiment duration, making it a promising tool for the development of new ophthalmic drugs.
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The possibilities of using the chick embryo and its individual structures as a model system in experimental ophthalmology are considered. Cultures of the retina and spinal ganglia from chick embryos are used in the development of new methods for the treatment of glaucomatous optic neuropathy and ischemic optic neuropathy. The chorioallantoic membrane is used for modelling vascular pathologies of the eye, screening of anti-VEGF drugs, and assessing biocompatibility of implants.

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In recent years, due to the aging of the population and the development of diagnostic medicine, the number of identified diseases associated with the accumulation of amyloid proteins has increased. Some of these proteins are known to cause a number of degenerative diseases in humans, such as amyloid-beta (Aβ) in Alzheimer's disease (AD), α-synuclein in Parkinson's disease (PD), and insulin and its analogues in insulin-derived amyloidosis. In this regard, it is important to develop strategies for the search and development of effective inhibitors of amyloid formation.

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Loss of vision is a pressing medical and social problem leading to profound disability, loss of ability to work, serious alterations in the psycho-emotional state, and a decline of the quality of life. When conservative or surgical treatment can not help restore vision, the use of visual prosthesis - bionic eye - can be an effective solution. This review covers the main modern approaches to the development of visual prosthetic systems.

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Antibiotic-resistant bacteria are recognized as one of the leading causes of death in the world. We proposed and successfully tested peptides with a new mechanism of antimicrobial action "protein silencing" based on directed co-aggregation. The amyloidogenic antimicrobial peptide (AAMP) interacts with the target protein of model or pathogenic bacteria and forms aggregates, thereby knocking out the protein from its working condition.

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The increase in the resistivity with decreasing temperature followed by a drop by more than one order of magnitude is observed on the metallic side near the zero-magnetic-field metal-insulator transition in a strongly interacting two-dimensional electron system in ultra-clean SiGe/Si/SiGe quantum wells. We find that the temperature [Formula: see text], at which the resistivity exhibits a maximum, is close to the renormalized Fermi temperature. However, rather than increasing along with the Fermi temperature, the value [Formula: see text] decreases appreciably for spinless electrons in spin-polarizing (parallel) magnetic fields.

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The need to develop new antimicrobial peptides is due to the high resistance of pathogenic bacteria to traditional antibiotics now and in the future. The creation of synthetic peptide constructs is a common and successful approach to the development of new antimicrobial peptides. In this work, we use a simple, flexible, and scalable technique to create hybrid antimicrobial peptides containing amyloidogenic regions of the ribosomal S1 protein from .

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We studied the antioxidant and cytoprotective effects of meconic acid in the model systems. Meconic acid, similar to commercial drug Mexidol, reduced the intensity of chemiluminescence in the model system of yolk lipoproteins. Meconic acid also reduced the toxic effect of glutamate on neurons in the primary cerebellar culture, but had no effect on cell viability under normal conditions.

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The development and testing of new antimicrobial peptides (AMPs) represent an important milestone toward the development of new antimicrobial drugs that can inhibit the growth of pathogens and multidrug-resistant microorganisms such as Gram-negative bacteria. Most AMPs achieve these goals through mechanisms that disrupt the normal permeability of the cell membrane, which ultimately leads to the death of the pathogenic cell. Here, we developed a unique combination of a membrane penetrating peptide and peptides prone to amyloidogenesis to create hybrid peptide: "cell penetrating peptide + linker + amyloidogenic peptide".

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Research in recent years has shown that there is a close connection between the brain and the intestine through neuronal, endocrine and immune pathways. The introduction of probiotics into the diet of animals and humans helps to reduce the level of anxiety and depression, as well as inflammatory processes during emotional stress. of this work was to study the effect of intragastric administration of Bifidobacterium adolescentis and Lactobacillus acidophilus on oxidative processes in the brain tissues and the level of anxiety in rats under conditions of normoxia and acute hypoxia with hypercapnia.

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Here, we describe the draft genome sequence of strain X-BIO-1, which contains 16 contigs, comprising 3,861,135 bp with a G+C content of 46.54%. The annotated draft genome contains 3,710 protein-coding genes and 62 RNA genes.

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We propose a method for designing optical elements with two freeform refracting surfaces generating prescribed non-axisymmetric irradiance distributions in the case of an extended light source. The method is based on the representation of the optical surfaces as bicubic splines and on the subsequent optimization of their parameters using a quasi-Newton method. For the fast calculation of the merit function, we propose an efficient version of the ray tracing method.

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Aim: To assess the efficacy of transcranial electrostimulation TES for treatmnet of anxiety-like behavior and motor disorders in rats with rotenone-induced parkinsonism.

Material And Methods: The study was performed on 30 mature male-rats. Animals were divided into following groups: control, intact rats (group 1); rats with an experimental model of parkinsonism without treatment (group 2); rats with an experimental model of parkinsonism, which had 7 sessions of TES-therapy (group 3), the number of rats in each group was 10.

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Ignited by the discovery of the metal-insulator transition, the behaviour of low-disorder two-dimensional (2D) electron systems is currently the focus of a great deal of attention. In the strongly interacting limit, electrons are expected to crystallize into a quantum Wigner crystal, but no definitive evidence for this effect has been obtained despite much experimental effort over the years. Here, studying the insulating state of a 2D electron system in silicon, we have found two-threshold voltage-current characteristics with a dramatic increase in noise between the two threshold voltages.

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Using ultra-high quality SiGe/Si/SiGe quantum wells at millikelvin temperatures, we experimentally compare the energy-averaged effective mass, m, with that at the Fermi level, m , and verify that the behaviours of these measured values are qualitatively different. With decreasing electron density (or increasing interaction strength), the mass at the Fermi level monotonically increases in the entire range of electron densities, while the energy-averaged mass saturates at low densities. The qualitatively different behaviour reveals a precursor to the interaction-induced single-particle spectrum flattening at the Fermi level in this electron system.

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The supporting quadric method (SQM) is a versatile method for the design of a wide class of freeform optical elements. In the present work, a novel SQM-based approach for the computation of total internal reflection (TIR) optical elements generating arbitrary narrow-angle light distributions is proposed. High performance of the presented method is confirmed by two designed optical elements: the first one forms an illuminance distribution in a square region with angular size of 17°, and the second one generates a bat-shaped uniformly illuminated area with an angular size of 43.

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The development of LED secondary optics for road illumination is quite a challenging problem. Optical elements developed for this kind of application should have maximal efficiency, provide high luminance and illuminance uniformity, and meet many other specific requirements. Here, we demonstrate that the usage of the supporting quadric method modification enables generating free-form optical solution satisfying all these requirements perfectly.

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To improve the optical performance of LED-based lighting devices, refractive optical elements are usually used. We propose a novel technique for the computation of free-form optical elements with two refractive surfaces generating the required illuminance or intensity distribution. The proposed approach makes it possible to control the balance of deflection angles between the inner and outer surfaces of the optical element.

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