Новые публикации

https://doi.org/10.1016/j.ijbiomac.2026.150299

The paper describes the rational design and truncation of high-affinity DNA aptamer ApTnI12 targeting cardiac troponin I (cTnI), a key biomarker for early diagnosis of cardiac injury. By combining molecular modeling, surface plasmon resonance, and bioluminescent assay, a series of truncated variants of ApTnI12 were obtained and studied to elucidate the role of its structural elements in mediating the aptamer's affinity and specificity. The G-quadruplex motif was shown to be essential for maintaining the aptamer stability and to play a key role in the cTnI epitope recognition, during which the flanking duplex regions and loops significantly contributed to binding strength and specificity through electrostatic and hydrogen bonding interactions. The specificity of the aptamer consisting of only G-quadruplex was significantly reduced, highlighting the need for careful monitoring of its non-specific binding. A rationally designed random duplex aptamer variant achieved comparable affinity to SELEX-derived aptamers, though with a compromise in specificity. These findings emphasize the importance of balancing structural elements in the aptamer design and underscore the need for integrated computational and empirical approaches for developing aptamers with optimal performance in biosensing and therapeutic applications.

https://doi.org/10.1007/s10948-025-07130-3

The evolution with interaction of the electronic structure of the triangular Hubbard model, which is believed to be the parent model for describing the electronic structure of twisted bilayer dichalcogenides, is studied within the cluster perturbation theory using 13-site clusters. Local and non-local correlations are taken into account within a cluster, while the intercluster hopping is considered using perturbation theory. We obtain the evolution of the electronic structure from metal to insulator through the pseudogap state with increasing interaction. We show that this pseudogap state is characterized by the arc–like Fermi surface with maximum spectral weight located in the Γ−� directions. The energy distribution curves at the Fermi level are not characterized by a strong spectral function peak. Such momentum-dependent behavior of pseudogap suppression of spectral function is not typical for the most familiar pseudogap in doped cuprates in the presence of strong antiferromagnetic correlations and can lead to momentum-uniform pseudogap.

 http://crm-en.ics.org.ru/journal/article/3672/

The work presents an experimental study of the tree structure that occurs during a medical examination. At each meeting with a medical specialist, the patient receives a certain number of areas for consulting other specialists or for tests. A tree of directions arises, each branch of which the patient should pass. Depending on the branching of the tree, it can be as final — and in this case the examination can be completed — and endless when the patient’s goal cannot be achieved. In the work both experimentally and theoretically studied the critical properties of the transition of the system from the forest of the final trees to the forest endless, depending on the probabilistic characteristics of the tree.

For the description, a model is proposed in which a discrete function of the probability of the number of branches on the node repeats the dynamics of a continuous gaussian distribution. The characteristics of the distribution of the Gauss (mathematical expectation of x0�0, the average quadratic deviation of σ�) are model parameters. In the selected setting, the task refers to the problems of branching random processes (BRP) in the heterogeneous model of Galton – Watson.

Experimental study is carried out by numerical modeling on the final grilles. A phase diagram was built, the boundaries of areas of various phases are determined. A comparison was made with the phase diagram obtained from theoretical criteria for macrosystems, and an adequate correspondence was established. It is shown that on the final grilles the transition is blurry.

The description of the blurry phase transition was carried out using two approaches. In the first, standard approach, the transition is described using the so-called inclusion function, which makes the meaning of the share of one of the phases in the general set. It was established that such an approach in this system is ineffective, since the found position of the conditional boundary of the blurred transition is determined only by the size of the chosen experimental lattice and does not bear objective meaning.

The second, original approach is proposed, based on the introduction of an parameter of order equal to the reverse average tree height, and the analysis of its behavior. It was established that the dynamics of such an order parameter in the σ=const�=const section with very small differences has the type of distribution of Fermi – Dirac (σ� performs the same function as the temperature for the distribution of Fermi – Dirac, x0�0 — energy function). An empirical expression has been selected for the order parameter, an analogue of the chemical potential is introduced and calculated, which makes sense of the characteristic scale of the order parameter — that is, the values of x0�0, in which the order can be considered a disorder. This criterion is the basis for determining the boundary of the conditional transition in this approach. It was established that this boundary corresponds to the average height of a tree equal to two generations. Based on the found properties, recommendations for medical institutions are proposed to control the provision of limb of the path of patients.

The model discussed and its description using conditionally-infinite trees have applications to many hierarchical systems. These systems include: internet routing networks, bureaucratic networks, trade and logistics networks, citation networks, game strategies, population dynamics problems, and others.

DOI: https://doi.org/10.1103/f6y7-qtzc

The dynamics of domain walls (DWs) was systematically investigated in epitaxial Pd/Co/Pd(111) samples with different thicknesses of the Pd bottom layer and, as a consequence, different interface roughnesses in the creep and flow regimes. The DWs were displaced by the simultaneous action of driving out-of-plane (OOP) and symmetry-breaking in-plane (IP) magnetic fields. A pronounced asymmetry in the dependencies of the velocities of the DWs on the applied IP magnetic field, 𝑣⁡(𝐻𝑥), was observed in the creep regime, which was related to the dependence of the mobility of the DWs on their chirality, presumably due to a chiral damping. The investigated samples revealed different depinning fields due to different interface roughnesses. Notably, the asymmetry in the 𝑣⁡(𝐻𝑥) dependencies almost disappeared in the flow regime, regardless of the extent of asymmetry observed in the creep regime and the values of depinning fields in the samples. We explain this fact by the precessional dynamics of DWs in the flow regime, in which the chirality of DWs changes between left-handed to right-handed with a large frequency, thus making DWs achiral on average. This study would deepen the understanding of the chiral dynamics of DWs and advance the development of DW devices.

DOI: https://doi.org/10.1103/qlq6-b67j

The multiferroic ferroborate GdF⁢e3⁢(B⁢O3)4 with huntite-type structure exhibits magnetic ordering below 𝑇N=38 K and contains two magnetic subsystems associated with Gd and Fe ions. Competing anisotropies of these subsystems drive a spin-reorientation transition at 𝑇SR=10.7 K, switching the ground state from easy-axis to easy-plane. Using antiferromagnetic resonance, we investigate the spin dynamics across this transition. The observed incomplete softening of a magnon mode during both field- and temperature-induced spin-reorientation transitions indicates the first-order nature of the phase transition, which is accompanied by a discontinuous jump in the effective anisotropy field. We reproduce this behavior using a simple model that attributes the jump in the anisotropy field to the presence of an effective fourth-order anisotropy constant, responsible for the discontinuous character of the transition. Remarkably, for in-plane magnetic fields, we identify a new AFMR mode that persists from 12 K up to 𝑇N. This mode likely corresponds to the dynamics of a long-period incommensurate state, previously detected by resonant elastic x-ray scattering.

https://doi.org/10.1063/5.0302922

Efficient heating of magnetic nanoparticles by means of the ferromagnetic resonance method is demonstrated with the use of isotropic superparamagnetic nickel ferrite powder as an example. The kinetic heating curves Δ�(�) were measured at frequency of �=8.9GHz⁠. It is shown that the obtained Δ� values are fairly well described by theoretical expressions for the absorption of microwave energy in an isotropic superparamagnet. This imparts some basic quantification to the idea of magnetic hyperthermia that operates in the ultra-high frequency range.

DOI: 10.47475/2500-0101-2025-10-2-395-404

Heating of the ferrihydrite (Fe2O3 (H2O)), hematite (-Fe2O3), maghemite (-Fe2O3), cobalt ferrite (CoFe2O4) powders in the ferromagnetic resonance (FMR) mode has been studied. It is shown that the temperature increment is determined by the magnetization of the powders and depends linearly on the squared magnetic component of a microwave f ield. It is demonstrated by the example of CoFe2O4 that heating of magnetic powders in the FMR mode can occur by means of the natural ferromagnetic resonance. The Fe2O3 SiO2NH2 FAS9 composite particles capable of effectively binding to tumor cells of Ehrlich ascites carcinoma have been synthesized. It is shown that magnetic resonance hyperthermia leads to a decrease in the viability of tumor cells.

https://www.mathnet.ru/php/archive.phtml?wshow=paper&jrnid=jsfu&paperid=1296&option_lang=rus

Исследована возможность применения суперпарамагнитных наночастиц на основе магнетита с полисахаридным покрытием, функционализированных аптамером, для визуализации опухолей in vivo на примере асцитной карциномы Эрлиха с помощью МРТ. Синтезированные наночастицы исследованы методами просвечивающей электронной микроскопии, мессбауэровской спектроскопии и ферромагнитного резонанса. Синтезированные наночастицы конъюгировали с аптамером As42, специфичным к клеткам карциномы Эрлиха (As42-Fe${}_3$O${}_4$-AG). Показана возможность применения препарата As42-Fe${}_3$O${}_4$-AG в качестве контрастирующего агента для МРТ-визуализации опухолей у мышей, которые образовались в легких животных через 2 недели после внутрилегочного введения клеток асцитной карциномы Эрлиха. Аптамер AS42 адресно доставляет в опухолевые очаги суперпарамагнитные наночастицы на основе магнетита (Fe${}_3$O${}_4$-AG), которые контрастируют при МРТ сканировании ткани. Препарат позволяет специфично распознавать с помощью МРТ солидные опухоли легких, что подтверждается с помощью аутопсии.

https://doi.org/10.1134/S0040577925120128

Experimental studies of magnetic properties of a topological van der Waals antiferromagnet insulator MnBi2Te4 demonstrated not only an anomalous behavior of magnetization before and after the spin-flop transition but also its strong temperature dependence. To interpret these effects, we present a quantum theory of layered antiferromagnet with a trigonal symmetry of the triangular lattice. Using atomic representations for spin operators and the diagram technique for Hubbard operators, we obtain a dispersion equation describing the temperature dependence of the excitation spectrum. In the anisotropic self-consistent field approximation, we derive a transcendent equation establishing an interrelation between the Néel temperature and model parameters. For the weak-anisotropy case, we obtain its analytical solution. We describe the temperature evolution of magnetization as a function of magnetic field and construct a phase diagram showing regions where different configurations of MnBi2Te4 magnetic sublattices are realized. We observe that quantum effects induced by the trigonal component of the single-ion anisotropy essentially affect the thermodynamic properties of antiferromagnets

https://doi.org/10.3390/molecules30244794

Owing to the fact that ultrathin platinum films have many practical applications, the information concerning the initial stage of the formation of these films raises considerable interest. The effect of the film thickness on the morphology, as well as on the electrical and optical properties, was experimentally studied by a combination of methods (TEM, SAED, SEM, AFM, optical spectrophotometry, and electrical resistance measurements). The growth mechanisms of the films with an average thickness from 0.2 to 20 nm were determined, which is equivalent to the thickness of 1 to 100 monolayers (ML). The percolation threshold was reached, with the average film thickness being ≈1.0 nm, when electrical conductivity appeared. With an average thickness of ≈2.0 nm, the platinum films became almost continuous. The obtained data were analyzed within the framework of scaling theory. The growth of the platinum films at the initial stage (0.2–2.0 nm) was shown to proceed in the mixed 2D/3D growth mode. Here, 3D nanoislands, having a crystalline structure, were formed simultaneously with the formation of an almost continuous 2D subnanometer layer possessing an amorphous-like structure.

DOI: https://doi.org/10.1103/rq46-g378

We revise the temporal coupled mode theory to describe the resonant response of quasiguided modes under oblique incidence in periodic dielectric metasurfaces accounting for the constraints imposed by the symmetry of the unit cell. We derive a universal expression for the Fano resonance line shape in reflection and transmission for subwavelength period metasurfaces and reveal a fundamental link between the Fano parameters and unit cell symmetries, including robust reflection and transmission zeros, as well as spectral signatures of bound states in the continuum. To demonstrate the power of the developed theory, we provide a generalized framework for analyzing asymmetry in the coupling and decoupling coefficients. This allows us to reveal the dual nature of unidirectional guided resonances and counter-propagating modes characterized by single-sided coupling to incident waves, which have been actively discussed in recent years. These insights provide a powerful analytical tool for designing high-Q resonances in metasurfaces through symmetry exploitation.

https://doi.org/10.1016/j.optcom.2025.132836

Orthorhombic strontium tetraborate (α-SBO) is a prospective optical material for future high-power applications in DUV and VUV. Limitations of α-SBO as a nonlinear optical material can be overridden by the use of spontaneous random domain structures inherent to this unique material. The present article reports spatially selective random quasi phase matching of nonlinear optical conversion in random structures of α-SBO that resulted in more than two orders of magnitude efficiency enhancement for the frequency doubling to the blue spectral region due to employing excellent radiation damage resistance of α-SBO and selection of most efficient parts of random structure. Further progress to DUV and VUV generation is prognosed via the development of technology in the direction of obtaining thinner average thickness of domains.

https://doi.org/10.1016/j.omtn.2025.102790

The SARS-CoV-2 spike (S) protein, crucial for viral entry, remains a key target for diagnostics and therapeutics amid evolving variants. Here, we describe the selection and characterization of novel DNA aptamers targeting the S1 subunit, including the Omicron strain, via systematic evolution of ligands by exponential enrichment (SELEX) and biolayer interferometry (BLI). Three aptamers—AptS1-tSP4, AptS1-tSP10, and AptS1-tSP11—exhibited nanomolar dissociation constants (14–59 nM), with AptS1-tSP10 demonstrating good selectivity over MERS-CoV and robust binding in human saliva and pseudovirus samples. Integration with proximity ligation assay and qPCR (PLA-qPCR) achieved a detection limit of 3 pM, surpassing many antibody-based methods. Mass spectrometry-based epitope mapping identified the receptor-binding domain (RBD) peptide VGGNYNYLYR as the primary binding site for AptS1-tSP10. Molecular dynamics and quantum mechanics simulations revealed stable interactions through hydrogen bonding and π-π stacking with neutral residues in both open and closed spike conformations, independent of variant mutations. These multifunctional aptamers offer a versatile platform for ultrasensitive, epitope-specific SARS-CoV-2 detection and pave the way for nucleic acid-based therapeutics to combat viral infections.

https://doi.org/10.1364/OE.578879

We theoretically consider orbital rotation of a spheroidal submicron particle in the field of two counter-propagating circularly polarized Gaussian beams. We derived equations connecting the parameters of the circular orbits centered on the beams axis to the optical force and torque. The equations show that, besides orbital rotation, the spheroidal particle simultaneously rotates around its equatorial axis. We found that two distinct dynamic regimes are possible. The orbital motion can be accompanied by a rapid proper rotation with angular velocity an order of magnitude larger than the angular velocity of the orbital rotation. Alternatively, the orbital and proper rotations can be synchronized. The direction of orbital rotation can either coincide with or be opposite to the direction of rotation of the electric vector. The findings are confirmed by direct numerical simulations. The results can be of use in development of nano-scale gyroscopes as well in shape-selective sorting of submicron particles.

https://doi.org/10.1364/OE.582556

The effects of the incidence angle and applied voltage on the polarization state of light passing through a cholesteric (CLC) with tangential-conical boundary conditions are investigated. Both cases in which the CLC director on the input substrate is perpendicular or parallel to the light incidence plane are considered. The polarization azimuth following mode is characterized as a function of the incidence angle and voltage. The wavelength-independent mode of change in light polarization has been discovered. The influence of the helix pitch and CLC layer thickness on the realized modes parameters is in good agreement with theoretical predictions based on the Frank-Oseen approach.

https://doi.org/10.1007/s40843-025-3691-9

Near-infrared (NIR) spectroscopy has significantly advanced NIR light sources. However, creating NIR emitters with optimal luminescence properties, high thermal stability, and adjustable emission peaks poses a critical challenge for future smart NIR devices. We introduced a chemical unit cosubstitution strategy by incorporating Ca²⁺ and Sn⁴⁺ ions into the garnet structure. Through this approach, Y_3−yCa_yGa_4.95−ySn_yG₁₂:0.05Cr³⁺ (y = 0–1) phosphors were developed by modulating the A&C ligands, resulting in emission centers ranging from 708 to 768 nm. The modified local environment of Cr³⁺ accounts for the increased light intensity (2.71 times) and broadening observed. Furthermore, this study investigated the impact of varying Cr³⁺ concentrations (Y_2.6Ca_0.4Ga_4.6−xSn_0.4G₁₂:xCr³⁺) on the production of high-performance phosphors. Compared with Y₃Ga_4.93G₁₂:0.07Cr³⁺, the optimized phosphor exhibited exceptional external quantum efficiency (EQE = 34.96%). The luminescence enhancement is attributed to an increase in radiative transitions caused by octahedral Jahn-Teller distortion, whereas the notable thermal stability (91.3% at 423 K) is attributed to the presence of weak electron-phonon coupling (EPC) and oxygen vacancy (O_V) defects. Finally, by combining it with a 450 nm blue LED chip, we constructed a near-infrared phosphor-converted LED (NIR pc-LED) device with superior electroluminescence efficiency (18.8% @ 100 mA), increasing the ultralow quenching rate (< 5% intensity loss after 30 days of operation) and demonstrating remarkable performance in plant lighting applications.

https://doi.org/10.1080/1536383X.2025.2595222

Nickel nanoparticles encapsulated in a continuous carbon shell (Ni@C) were synthesized in a helium arc-discharge plasma, purified by acid treatment, and subsequently decorated with palladium via the thermal decomposition of palladium acetylacetonate, as confirmed by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The reaction of methanol oxidation in an acidic medium was investigated using cyclic voltammetry on the composite (Pd,PdO/Ni@C) applied to a graphite electrode. It was demonstrated that the composite possesses electrochemical activity and can be used as an anode in acidic direct methanol fuel cells.