New Publications

Modification of Synthetic Valleriite Surface with Gold Nanoparticles: The Roles of Specific Adsorption and Zeta Potential

Karacharov, A.A., Likhatski, M.N., Borisov, R.V., (...), Vorobyev, S.A., Zharkov, S.M.// Colloid Journal//

https://doi.org/10.1134/S1061933X23601075

Layered two-dimensional materials, whose properties dramatically differ from their bulk precursors, are of great theoretical and applied importance. Recently, a layered 2D material, an analog of a natural mineral, valleriite, in which quasi-monoatomic Cu−Fe−S sheets alternate with brucite-like ones, has been prepared using a simple hydrothermal synthesis procedure. The features of the electronic structure of these materials make it possible to propose them as new materials for a wide field of applications such as (electro)photocatalysis, high-capacity batteries, etc. In this work, nanocomposite materials have been prepared via immobilization of gold nanoparticles (AuNPs) from citrate hydrosols on the surface of the synthesized valleriites having different compositions of hydroxide layers, which control the surface charge density. According to X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy-dispersive X-ray microanalysis (EDX), and selected area electron diffraction (SAED) data, AuNPs are immobilized on valleriite nanoflakes, which have lateral sizes of 150–200 nm and thicknesses of several tens of nanometers, as isolated metal nanoparticles with an average diameter of 11 nm. A small amount of aggregates indicates a high affinity of AuNPs for the valleriite surface. The amounts of immobilized gold are the same on all studied valleriites (~0.2%). This finding may be related to the simultaneous sorption of free citrate ions from the AuNP hydrosols, with these ions, according to zeta potential measurements, charging the surfaces of all studied valleriite samples to nearly the same negative value of –40 mV. According to the XPS data, the AuNPs immobilization markedly decreases the magnesium and oxygen contents on the surfaces of the synthesized valleriites due to the partial degradation/dissolution of the brucite layer. In addition, the amount of Fe3+ ions bound to OH groups decreases with a simultaneous increase in the fraction of Fe3+–O species. The TEM data have confirmed the preservation of the layered structure of valleriites after the immobilization of AuNPs.

Optical transmission modulation and spectral properties of self-organized nematic domains

Parshin, A.M., Zyryanov, V.Y., Shabanov, V.F.// Optical Materials//

https://doi.org/10.1016/j.optmat.2024.115232

The modulation and spectral characteristics of self-organized ensembles of nematic domains with the disclination lines non-aligned and aligned in a magnetic field have been studied using an electric field. The obtained experimental voltage dependences of the light transmission agree well with the dependences calculated using the model considerations. These dependences have been compared with the electro-optical characteristics of a homogeneous planar nematic layer. The amplitude component of the optical transmission determined by light scattering and the oscillating component caused by the phase modulation have been examined. The effect of the spectral dispersion of transmission on the electro-optical characteristics of domain ensembles has been evaluated.

Magnetic flux trapping in porous high-Tc superconductors

Gokhfeld, D.// Physica C//

https://doi.org/10.1016/j.physc.2024.1354486

Porosity affects the properties of high-Tc superconductors and can improve their performance by enhancing oxygenation, cryocooling, etc. Among other factors, the presence of pores plays a significant role in the process of magnetic flux trapping. Relationships with the porosity manifest in the irreversibility field, the full penetration field, and the remnant magnetization of the samples. To account for the effect of porosity on the trapped magnetic flux into type-II superconductors, a simple toy model is suggested. Generally, as the porosity increases, the trapped flux and related parameters tend to diminish. However, in the case of microscopic samples, porosity can enhance magnetic flux trapping.

Highly-Efficiency Far-Red Emission in Cr3+ Activated Ca1.8Mg1.2Al2Ge3O12 toward Plant Precise Lighting

Chaowei Yang, Dongwei Zheng, Xikun Zou, Xiangyi Dai, Baoling Tang, Maxim S. Molokeev, Xuejie Zhang, Haoran Zhang, Yingliang Liu, Bingfu Lei// Advanced Optical Materials//

 https://doi.org/10.1002/adom.202303235

Far-red (FR) region (beyond 700 nm) lighting sources possess special potential for plant lighting. However, it remains a challenge to obtain high-performance Cr3+-doped FR phosphors. This study developed a FR phosphor, Ca1.8Mg1.2Al2Ge3O12:Cr3+ (CMAGG: Cr3+), using the cation substitution strategy. Under 438 nm blue light excitation, the phosphors display FR emission centered at 720 nm with a full width at half maximum (FWHM) of 91 nm. Benefit from the favorable match with the FR phytochrome (Pfr), the phosphor is combined with InGaN blue light chips to create a FR phosphor-converted light-emitting diode (pc-LED), which is used in Italian lettuce growth experiments and it results shown in a 15% increase in fresh weight and a 6.5% increase in dry weight. Notably, supplemental FR light modulated its growth morphology. The results of this study will be useful for further research on novel Cr3+-doped FR phosphors to meet the precise spectral requirements for plant growth.

Two-Dimensional Hybrid Perovskite with High-Sensitivity Optical Thermometry Sensors

Mengyu Guan, Jiarui Hao, Lei Qiu, Maxim S. Molokeev, Lixin Ning*, Zhigao Dai*, and Guogang Li// Inorganic Chemistry //

https://doi.org/10.1021/acs.inorgchem.3c04140

Optical thermometry has gained significant attention due to its remarkable sensitivity and noninvasive, rapid response to temperature changes. However, achieving both high absolute and relative temperature sensitivity in two-dimensional perovskites presents a substantial challenge. Here, we propose a novel approach to address this issue by designing and synthesizing a new narrow-band blue light-emitting two-dimensional perovskite named (C8H12NO2)2PbBr4 using a straightforward solution-based method. Under excitation of near-ultraviolet light, (C8H12NO2)2PbBr4 shows an ultranarrow emission band with the full width at half-maximum (FWHM) of only 19 nm. Furthermore, its luminescence property can be efficiently tuned by incorporating energy transfer from host excitons to Mn2+. This energy transfer leads to dual emission, encompassing both blue and orange emissions, with an impressive energy transfer efficiency of 38.3%. Additionally, we investigated the temperature-dependent fluorescence intensity ratio between blue emission of (C8H12NO2)2PbBr4 and orange emission of Mn2+. Remarkably, (C8H12NO2)2PbBr4:Mn2+ exhibited maximum absolute sensitivity and relative sensitivity values of 0.055 K–1 and 3.207% K–1, respectively, within the temperature range of 80–360 K. This work highlights the potential of (C8H12NO2)2PbBr4:Mn2+ as a promising candidate for optical thermometry sensor application. Moreover, our findings provide valuable insights into the design of narrow-band blue light-emitting perovskites, enabling the achievement of single-component dual emission in optical thermometry sensors.

The Effect of Dielectric Relaxation Processes on the Complex Dielectric Permittivity of Soils at Frequencies From 10 kHz to 8 GHz-Part II: Broadband Analysis

Pavel P. Bobrov; Elena S. Kroshka; Konstantin V. Muzalevskiy// Ieee Transactions On Geoscience And Remote Sensing //

DOI: 10.1109/TGRS.2023.3340693

This article is the second in a series evaluating the effect of dielectric relaxation processes on the relatively effective complex dielectric permittivity (RCP) of soils. Part II is based on the results of experimental measurements in the frequency range 10 kHz to 8–20 GHz. The broadband dielectric spectrum model includes the high-frequency part as a model of the dielectric mixture and the relaxation part as the sum of three relaxation processes modeled by the Debye and Cole–Cole formulas. For modeling the high-frequency part of the spectrum, the Dobson and Mironov models were considered as possible options. As stated in Part I, the influence of relaxation processes on the imaginary part of the RCP extends up to frequencies of units of gigahertz. The increase in the imaginary part in these models was compensated by unrealistically high values of the specific electrical conductivity of free and bound water. We examined the correspondence of these models to experimental data at frequencies above 2–5 GHz, assuming that the conductivity of bound and free water is zero. The parameters of relaxation processes were found while solving the least-square optimization problem using the technique for determining the continuous distribution of relaxation times (DRTs). Found process parameters depend on the content of clay, organic carbon, and moisture of the samples. The more clay is in the soil, the greater the strength of these processes is. The influence of organic carbon with the conditions being equal consists in the reduction of the real and imaginary parts of RCP.

Characterizing Aptamer Interaction with the Oncolytic Virus VV-GMCSF-Lact

by Maya A. Dymova 1,*ORCID,Daria O. Malysheva 1,2ORCID,Victoria K. Popova 1ORCID,Elena V. Dmitrienko 1ORCID,Anton V. Endutkin 1ORCID,Danil V. Drokov 1,2,Vladimir S. Mukhanov 1,2,Arina A. Byvakina 1,2ORCID,Galina V. Kochneva 3ORCID,Polina V. Artyushenko 4,5ORCID,Irina A. Shchugoreva 4,5ORCID,Anastasia V. Rogova 4,5ORCID,Felix N. Tomilin 5,6ORCID,Anna S. Kichkailo 4,5,Vladimir A. Richter 1 andElena V. Kuligina 1ORCID// Molecules //

https://doi.org/10.3390/molecules29040848

Aptamers are currently being investigated for their potential to improve virotherapy. They offer several advantages, including the ability to prevent the aggregation of viral particles, enhance target specificity, and protect against the neutralizing effects of antibodies. The purpose of this study was to comprehensively investigate an aptamer capable of enhancing virotherapy. This involved characterizing the previously selected aptamer for vaccinia virus (VACV), evaluating the aggregation and molecular interaction of the optimized aptamers with the recombinant oncolytic virus VV-GMCSF-Lact, and estimating their immunoshielding properties in the presence of human blood serum. We chose one optimized aptamer, NV14t_56, with the highest affinity to the virus from the pool of several truncated aptamers and built its 3D model. The NV14t_56 remained stable in human blood serum for 1 h and bound to VV-GMCSF-Lact in the micromolar range (Kd ≈ 0.35 μM). Based on dynamic light scattering data, it has been demonstrated that aptamers surround viral particles and inhibit aggregate formation. In the presence of serum, the hydrodynamic diameter (by intensity) of the aptamer–virus complex did not change. Microscale thermophoresis (MST) experiments showed that NV14t_56 binds with virus (EC50 = 1.487 × 109 PFU/mL). The analysis of the amplitudes of MST curves reveals that the components of the serum bind to the aptamer–virus complex without disrupting it. In vitro experiments demonstrated the efficacy of VV-GMCSF-Lact in conjunction with the aptamer when exposed to human blood serum in the absence of neutralizing antibodies (Nabs). Thus, NV14t_56 has the ability to inhibit virus aggregation, allowing VV-GMCSF-Lact to maintain its effectiveness throughout the storage period and subsequent use. When employing aptamers as protective agents for oncolytic viruses, the presence of neutralizing antibodies should be taken into account.

Strain-induced charge ordering above room temperature in rare-earth manganites

Samoshkina, Y., Rautskii, M., Neznakhin, D., (...), Zaikovskii, V., Chernichenko, A.// Dalton Transactions//

Most known mixed manganites containing rare-earth elements demonstrate a pronounced charge ordering (CO) state below room temperature. The behavior of the magnetic susceptibility and electronic magnetic resonance of polycrystalline Pr1−xSrxMnO3/YSZ (x = 0.2 and x = 0.4) films without a pronounced texture indicates the formation of the CO phase in the samples at temperatures close to and above room temperature. Moreover, this phase manifests itself with a typical sign of martensitic transformation. The same phenomenon has been traced for textured polycrystalline La0.7Sr0.3MnO3/YSZ films. Electron microscope data indicate the presence of internal strain within the films, which is probably responsible for the formation of the CO phase. It is assumed that the reasons for the appearance of such strain include the crystallite size and the boundary between them. The results obtained provide the basis for the development of new research and technological tasks for the generation of the high-temperature CO state in various polycrystalline rare-earth manganites, since this state contributes to the manifestation of interesting magnetocaloric, magnetoelectric and multiferroic properties. In addition, recent data has opened up new opportunities for studying the strain-induced phenomena in such materials.

Relaxation of the trapped magnetic flux in a mesoscopic HTS with artificial pinning in the form of submicron holes

Maksimova, A.N., Gokhfeld, D.M., Moroz, A.N., Kashurnikov, V.A.// Chinese Journal of Physics//

https://doi.org/10.1016/j.cjph.2023.11.030

Vortex relaxation has been studied in a microsized HTS with various distributions of artificial pinning in the form of submicro-holes. It has been shown that, in some cases, for a superconductor with dimensions up to several micrometers, the time dependences of the trapped magnetic field do not correspond with the collective creep model. The dependences of the trapped-field relaxation rate and vortex activation energy on the magnetizing field (up to 0.5 T) and temperature (up to 50 K) have been obtained. It has been shown that the presence of submicro-holes slightly increases the relaxation rate, mainly due to the decrease in the number of random nanosized pinning centers.

On the use of dual-polarized multi-angular observations of P-band brightness temperature for soil moisture profile retrieval in thawed mineral soil

Konstantin V. Muzalevskiy,Jeffrey P. Walker,Foad Brakhasi,Nan Ye,Xiaoling Wu &Xiaoji Shen// International Journal Of Remote Sensing //

https://doi.org/10.1080/01431161.2024.2313993

This article investigated the possibility of remotely sensing the soil moisture profile in thawed soil from multi-angular dual-polarized brightness temperature (TB) observations at P-band frequencies of 750 MHz and 409 MHz using a modified Burke model. Moreover, it was found that an excellent agreement (coefficient of determination R2 = 0.999 and root-mean-square error (RMSE) no more than RMSE = 0.6 K) could be achieved between the Njoku coherent brightness temperature model and the modified Burke model by introducing a reflectivity from the air-soil interface that takes into account the phases of the multiple re-reflected waves in the underlying layers. Based on the modified Burke model, the depths from which apparent moisture and temperature could be retrieved in a dielectrically-inhomogeneous, non-isothermal soil were investigated, being approximately ten times less than the depth for which apparent soil temperature could be retrieved. In general, the thickness of the emitting layer depends on the TB look angle and polarization, along with the moisture and temperature profiles of the soil. It was also shown that due to the effect of the Brewster angle, the H-polarization of TB was twice as sensitive (4 K/1%) to changes in volumetric soil moisture than V-polarization (1.9 K/1%). Based on multi-angular (10°-50°) observations of TB at H- and V-polarizations, a method of moisture profile retrieval in the top 5–15 cm soil (depending on surface moisture) was proposed using an exponential fitting function, the parameters of which are found in the course of solving the inverse problem. A decrease in the sensing frequency from 750 MHz to 409 MHz makes it possible to increase the accuracy of soil moisture profiles retrieval by a factor of two, being from RMSE = 1.6% (R2 = 0.946) to RMSE = 0.85% (R2 = 0.982) in the top 15 cm layer of soil. The conducted investigation shows the promise of using P-band observations of TB for soil moisture profile retrieval.

Synthesis of Ni nanoclusters supported on diamond by plasma technique and their electrochemical properties

Nikita Nikolaev a, Victoria Isakova a, Natalia Vnukova a b, Victoria Еlesina a b, Gariy Glushenko a, Yevgeny Tomashevich a c, Grigory Churilov // Diamond And Related Materials //

https://doi.org/10.1016/j.diamond.2024.110844

In this study, particles of synthetic undoped diamond (DN) obtained via the high pressure – high temperature method were coated with a nickel shell using metallic nickel plasma in a two-jet plasma generator with gas vortex and magnetic flux stabilization. Through the use of scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, we observed the formation of a nickel diamond composite with a core-shell structure, where DN serves as the core and Ni nanoclusters form the shell (DN@Ni). The results of voltammetric analysis indicated that DN@Ni, when deposited on a graphite electrode, exhibited significant electrocatalytic activity in the oxidation of methanol and paracetamol in an alkaline electrolyte.

Effect of the spin crossover of local copper-oxygen states on the electronic structure of HTSC cuprates

Makarov, I. A.; Ovchinnikov, S. G.// arXiv.org, e-Print Archive, Condensed Matter//

https://doi.org/10.48550/arXiv.2402.00547

In this work, the effect of uniaxial pressure along the c axis on the electronic structure of the HTSC cuprate La2-xSrxCuO4 is investigated at the doping levels x = 0.1, 0.15, 0.25. The GTB method within the five-band p-d model framework is used to describe the electron system. The uniaxial compression leads to a significant reconstruction of the electronic structure and a change in the character of low-energy quasiparticle excitations: a large contribution of a1g symmetry orbitals appears at the top of the valence band. The crossover between the local Zhang-Rice singlet and the Emery-Reiter triplet was found at the pressure Pc = 15.1 GPa. The characteristic changes in the electronic structure under pressure occur abruptly as a result of the crossover. In particular, the top of the valence band displaces to the region around the k-point (pi,0), the Fermi contour transforms to the four pockets around (0,0),(2pi,0),(0,2pi),(2pi,2pi) and the one contour around (pi,pi).

A 10 GHz Monolithic Filter Based on Stripline Resonators with a Split Conductor

Govorun, I.V., Belyaev, B.A., Zav’yalov, Y.B., (...), Ugryumov, A.V., Galeev, R.G.// Doklady Physics//

https://doi.org/10.1134/S1028335823120030

The monolithic design of a compact bandpass filter X-band is made on the technology of multilayered printed circuit boards. Quarter-wave stripline resonators of the filter have two conductors divided by a layer of prepreg having low parameters that bond together the design. This eliminates the influence of the prepreg on the characteristics of the devices, ensuring good repeatability of filters in mass production. To increase the high-frequency stopband of the filter, one of the conductors of each resonator is cut in half by a transverse slit. The constructive sizes of the device were obtained by parametric synthesis using the electrodynamic analysis of its 3D model. The experimental data of the five-order filter are in good agreement with the electromagnetic simulation of filter of the 3D model. The experimental device has a central frequency of the passband of 10 GHz and a fractional bandwidth of 5.7%, and its dimensions and weight are 18.0 × 5.4 × 2.1 mm3 and 0.5 g. The important advantage of the developed design is the possibility of its installation on the board using the surface mounting method.

Revolutionizing physics: a comprehensive survey of machine learning applications

Suresh, R., Bishnoi, H., Kuklin, A.V., (...), Gharat, S., Hiba, P.// Frontiers in Physics//

https://doi.org/10.3389/fphy.2024.1322162

In the context of the 21st century and the fourth industrial revolution, the substantial proliferation of data has established it as a valuable resource, fostering enhanced computational capabilities across scientific disciplines, including physics. The integration of Machine Learning stands as a prominent solution to unravel the intricacies inherent to scientific data. While diverse machine learning algorithms find utility in various branches of physics, there exists a need for a systematic framework for the application of Machine Learning to the field. This review offers a comprehensive exploration of the fundamental principles and algorithms of Machine Learning, with a focus on their implementation within distinct domains of physics. The review delves into the contemporary trends of Machine Learning application in condensed matter physics, biophysics, astrophysics, material science, and addresses emerging challenges. The potential for Machine Learning to revolutionize the comprehension of intricate physical phenomena is underscored. Nevertheless, persisting challenges in the form of more efficient and precise algorithm development are acknowledged within this review.

Intense charge transfer plasmons in golden nanoparticle dimers connected by conductive molecular linkers

Fedorov, A.S., Visotin, M.A., Lukyanenko, A.V., Gerasimov, V.S., Aleksandrovsky, A.S.// Journal of Chemical Physics//

https://doi.org/10.1063/5.0183334

Golden nanoparticle dimers connected by conjugated molecular linkers 1,2-bis(2-pyridyl)ethylene are produced. The formation of stable dimers with 22 nm diameter nanoparticles is confirmed by transmission electron microphotography. The possibility of charge transfer through the linkers between the particles in the dimers is shown by the density functional theory calculations. In addition to localized plasmon resonance of solitary nanoparticles with a wavelength of 530 nm, the optical spectra exhibit a new intense absorption peak in the near-infrared range with a wavelength of ∼780 nm. The emergent absorption peak is attributed to the charge-transfer plasmon (CTP) mode; the spectra simulated within the CTP developed model agree with the experimental ones. This resonant absorption may be of interest to biomedical applications due to its position in the so-called transmission window of biological tissues. The in vitro heating of CTP dimer solution by a laser diode with a wavelength of 792 nm proved the efficiency of CTP dimers for achieving a temperature increase of ΔT = 6 °C, which is sufficient for hyperthermia treatment of malignant tumors. This indicates the possibility of using hyperthermia to treat malignant tumors using the material we synthesized.

Quantum SU(3)-ferrimagnet on triangular lattice

Martynov, A.S., Dzebisashvili, D.M.// Journal of Magnetism and Magnetic Materials//

https://doi.org/10.1016/j.jmmm.2024.171906

Manifestations of quantum effects in the macroscopic properties of frustrated magnets keep attracting considerable interest. We have formulated and studied a simple model of a three-sublattice mixed-spin (�=1,1/2,1/2��(3)-ferrimagnet on triangular lattice in which the strong quantum fluctuations are developed due to combined effect of frustrated exchange bonds, reduced dimensionality and a single-ion easy-plane anisotropy in the spin-1 sublattice. To account correctly for the ��(3) algebra, the Hubbard operators representation of generators is used. Dependencies of the magnetic moments  and �� (for spin-1/2 and spin-1 sublattices respectively), the total magnetic moment , as well as the quadrupole moment, on the anisotropy parameter  are calculated at zero temperature and different ratios �/� of exchange integrals from different sublattices. It is established that for �/�≪1 the critical value ��, at which the system enters the quadrupole antiferromagnetic phase, can be much smaller than both  and . Besides, with an increase in  from zero to �� the total moment  can change its direction several times via taking zero value. Classification of four branches of the spin-wave excitation spectrum of the ��(3)-ferrimagnet is carried out and modification of the spectrum with change in the single-ion anisotropy is analyzed.

Synthesis and properties of the NdSF compound, phase diagram of the NdF3–Nd2S3 system

Grigorchenko, V.M., Molokeev, M.S., Oreshonkov, A.S., (...), Elyshev, A.V., Andreev, O.V.// Journal of Solid State Chemistry//

https://doi.org/10.1016/j.jssc.2024.124640

The NdF3–Nd2S3 system attracts attention of researchers due to the possibility of using LnSF compounds (Ln = rare earth element) as possible new p- and n-type materials. The samples of this system were synthesized from NdF3 and Nd2S3. The NdSF compound belongs to the PbFCl structural type, P4/nmm space group, unit cell parameters: a = 3.9331(20) Å, c = 6.9081(38) Å. The experimentally determined direct and indirect NdSF bandgaps are equal to 2.68 eV and 2.24 eV. The electronic band structure was calculated via DFT simulation. The NdSF compound melts congruently at T = 1385 ± 10°С, ΔНm = 40.5 ± 10 kJ/mol, ΔS = 24.4 ± 10 J/mol. The NdSF microhardness is 455 ± 10 HV. Five phase transformations in the NdF3–Nd2S3 system were recorded by DSC; their balance equations were derived. The liquidus of the system calculated from the Redlich–Kister equation is fully consistent with the DSC data.

Highly-Efficiency Far-Red Emission in Cr3+ Activated Ca1.8Mg1.2Al2Ge3O12 toward Plant Precise Lighting

Yang, C., Zheng, D., Zou, X., (...), Liu, Y., Lei, B.// Advanced Optical Materials//

https://doi.org/10.1002/adom.202303235

Far-red (FR) region (beyond 700 nm) lighting sources possess special potential for plant lighting. However, it remains a challenge to obtain high-performance Cr3+-doped FR phosphors. This study developed a FR phosphor, Ca1.8Mg1.2Al2Ge3O12:Cr3+ (CMAGG: Cr3+), using the cation substitution strategy. Under 438 nm blue light excitation, the phosphors display FR emission centered at 720 nm with a full width at half maximum (FWHM) of 91 nm. Benefit from the favorable match with the FR phytochrome (Pfr), the phosphor is combined with InGaN blue light chips to create a FR phosphor-converted light-emitting diode (pc-LED), which is used in Italian lettuce growth experiments and it results shown in a 15% increase in fresh weight and a 6.5% increase in dry weight. Notably, supplemental FR light modulated its growth morphology. The results of this study will be useful for further research on novel Cr3+-doped FR phosphors to meet the precise spectral requirements for plant growth.

Characterizing Aptamer Interaction with the Oncolytic Virus VV-GMCSF-Lact

Dymova, M.A., Malysheva, D.O., Popova, V.K., (...), Richter, V.A., Kuligina, E.V.// Molecules//

 

https://doi.org/10.3390/molecules29040848

Aptamers are currently being investigated for their potential to improve virotherapy. They offer several advantages, including the ability to prevent the aggregation of viral particles, enhance target specificity, and protect against the neutralizing effects of antibodies. The purpose of this study was to comprehensively investigate an aptamer capable of enhancing virotherapy. This involved characterizing the previously selected aptamer for vaccinia virus (VACV), evaluating the aggregation and molecular interaction of the optimized aptamers with the recombinant oncolytic virus VV-GMCSF-Lact, and estimating their immunoshielding properties in the presence of human blood serum. We chose one optimized aptamer, NV14t_56, with the highest affinity to the virus from the pool of several truncated aptamers and built its 3D model. The NV14t_56 remained stable in human blood serum for 1 h and bound to VV-GMCSF-Lact in the micromolar range (Kd ≈ 0.35 μM). Based on dynamic light scattering data, it has been demonstrated that aptamers surround viral particles and inhibit aggregate formation. In the presence of serum, the hydrodynamic diameter (by intensity) of the aptamer–virus complex did not change. Microscale thermophoresis (MST) experiments showed that NV14t_56 binds with virus (EC50 = 1.487 × 109 PFU/mL). The analysis of the amplitudes of MST curves reveals that the components of the serum bind to the aptamer–virus complex without disrupting it. In vitro experiments demonstrated the efficacy of VV-GMCSF-Lact in conjunction with the aptamer when exposed to human blood serum in the absence of neutralizing antibodies (Nabs). Thus, NV14t_56 has the ability to inhibit virus aggregation, allowing VV-GMCSF-Lact to maintain its effectiveness throughout the storage period and subsequent use. When employing aptamers as protective agents for oncolytic viruses, the presence of neutralizing antibodies should be taken into account.

Spontaneous imbibition experiments for enhanced oil recovery with silica nanosols

Pryazhnikov, M.I., Zhigarev, V.A., Minakov, A.V., Nemtsev, I.V.// Capillarity//

https://doi.org/10.46690/capi.2024.03.02

Experimental oil displacement as a result of spontaneous imbibition of silica nanosols has been carried out using two types of sandstone as the reservoir rock. The permeability of the cores ranged from 0.34 to 333 mD, while the porosity was 11% and 22%, respectively. During the research, the influence of the concentration and nanoparticle size, as well as the permeability of the rock, on the process of spontaneous imbibition, was studied. Silica nanosols were considered as an object of study. The nanoparticle size ranged from 10 to 35 nm. The mass concentration of nanoparticles varied from 0.01% to 0.25%. It was found that the use of silica nanosols significantly increases the rate of the spontaneous imbibition process. It was established that a silica nanosol with a nanoparticle size of 10 nm and a concentration of 0.25% allows to displace more than six times oil compared to the reservoir water model in the same time. As a result, it was shown that the oil displacement efficiency and the efficiency of spontaneous imbibition increase along with an increase in the nanoparticle concentration and a decrease in the nanoparticle size.

Corrigendum to “Properties of degradable polyhydroxyalkanoates with different monomer compositions”

Volova, T., Kiselev, E., Nemtsev, I., (...), Ryltseva, G., Shishatskaya, E.// International Journal of Biological Macromolecules//

Magnetic structure and pressure-induced spin-crossover in Me3B2O6 (Me = Mn, Fe, Co, Ni) kotoites: Representation analysis and DFT calculations

Zhandun, V.S., Draganyuk, O.N., Zamkova, N.G.// Computational Materials Science//

https://doi.org/10.1016/j.commatsci.2024.112859

The magnetic and electronic properties of transition metal borates Me3B2O6 (Me = Mn, Fe, Co, Ni) with kotoite structure have been investigated at ambient and high pressures via a combination of representation analysis and density functional theory (DFT + U) calculations. Several magnetic configurations corresponding to the different irreducible representations have been considered. The total-energy calculations reveal that the magnetic ground state of Me3B2O6 kotoites is composition-dependent. The lowest energy magnetic phase of manganese and nickel kotoites is characterized by the antiferromagnetic ordering of the transition metal magnetic moments along the c- axis and along the b-axis for cobalt and iron kotoites. The magnetic cell of Ni3B2O6 kotoite corresponds to k = (1/2, 0, 1/2) vector and four time larger than the unit cell. The calculated exchange constants indicate the competition between ferromagnetic and antiferromagnetic interactions. At a critical pressure, Me ions undergo a high-spin to low-spin state crossover. This magnetic moments collapse is analyzed in terms of change in electronic structure under pressure.

Magnetic anisotropy and ferromagnetic resonance in inhomogeneous demagnetizing fields near edges of thin magnetic films

Solovev, P.N., Belyaev, B.A., Boev, N.M., Skomorokhov, G.V., Izotov, A.V.// Journal of Physics Condensed Matter//

DOI 10.1088/1361-648X/ad258c

Using local ferromagnetic resonance spectroscopy, we have studied the magnetic properties near edges of thin tangentially magnetized permalloy films, in which a well-defined uniaxial magnetic anisotropy was induced perpendicular to one of the edges. In the experiment, two samples with thicknesses of 90 and 300 nm and with slightly different compositions were examined. To explain the magnetization dynamics near edges, we propose a simple yet effective model of a film in the form of a rectangular prism, which yields the modified Kittel formula for the resonance frequency. In this formula, the locally averaged distance-dependent demagnetizing field that emerges near the edges is included as an additional uniaxial anisotropy term. The measurements reveal that at a certain distance from the edge, the resulting (apparent) anisotropy, determined from the angular dependencies of the resonance field, almost vanishes. Moreover, its easy axis reorients to become parallel to the edge. The model predictions agree well with these results, proving that the main resonance mode behavior near the film edges can be accurately described by introducing additional effective uniaxial anisotropy, provided the measuring area is relatively large. However, for the thick (300 nm) sample, additional precession modes are also observed. These modes distort the angular dependence of the main mode, thus demonstrating the limitations of the model.

Application of DUT-4 MOF structure switching for optical and electrical humidity sensing

Krylov, Alexander S; Shipilovskikh, Sergei A; Krylova, Svetlana N; Slyusarenko, Nina V; Timofeeva, Maria; Kenzhebayeva, Yuliya A; Bachinin, Semyon V; Yushina, Irina D; Cherepakhin, Aleksandr V; Shestakov, Nikolai P; et al// Dalton transactions //

DOI: https://doi.org/10.1039/D4DT00038B

The threshold structural transformation of the DUT-4 metal–organic framework (MOF) from an ordered to distorted phase during exposure to ambient conditions has been revealed. The in situ X-ray diffraction analysis, in situ Raman and FTIR spectroscopy, scanning electron microscopy and synchronous thermal analysis have been used for investigation. The reversible effect of exposure time and humidity on such a phase transition has been confirmed. We also demonstrated that the observed phase transition correlated well with changes in the optical and electronic properties of DUT-4, paving the way to a new family of MOF-based phase change materials for optoelectronic applications.

Two-Dimensional Hybrid Perovskite with High-Sensitivity Optical Thermometry Sensors

Guan, Mengyu; Hao, Jiarui; Qiu, Lei; Molokeev, Maxim S; Ning, Lixin; Dai, Zhigao; Li, Guogang// Inorganic chemistry//

https://doi.org/10.1021/acs.inorgchem.3c04140

Optical thermometry has gained significant attention due to its remarkable sensitivity and noninvasive, rapid response to temperature changes. However, achieving both high absolute and relative temperature sensitivity in two-dimensional perovskites presents a substantial challenge. Here, we propose a novel approach to address this issue by designing and synthesizing a new narrow-band blue light-emitting two-dimensional perovskite named (C8H12NO2)2PbBr4 using a straightforward solution-based method. Under excitation of near-ultraviolet light, (C8H12NO2)2PbBr4 shows an ultranarrow emission band with the full width at half-maximum (FWHM) of only 19 nm. Furthermore, its luminescence property can be efficiently tuned by incorporating energy transfer from host excitons to Mn2+. This energy transfer leads to dual emission, encompassing both blue and orange emissions, with an impressive energy transfer efficiency of 38.3%. Additionally, we investigated the temperature-dependent fluorescence intensity ratio between blue emission of (C8H12NO2)2PbBr4 and orange emission of Mn2+. Remarkably, (C8H12NO2)2PbBr4:Mn2+ exhibited maximum absolute sensitivity and relative sensitivity values of 0.055 K–1 and 3.207% K–1, respectively, within the temperature range of 80–360 K. This work highlights the potential of (C8H12NO2)2PbBr4:Mn2+ as a promising candidate for optical thermometry sensor application. Moreover, our findings provide valuable insights into the design of narrow-band blue light-emitting perovskites, enabling the achievement of single-component dual emission in optical thermometry sensors.

Theoretical Insights into the Mechanical Properties of DUT-8(Ni) MOF in the Open and Closed Pore Phases

Yushina, I.D., Matveychuk, Y.V., Krylov, A.S.// Crystal Growth and Design//

https://doi.org/10.1021/acs.cgd.3c01154

nsights into the mechanical properties of DUT-8(Ni) MOF crystals capable of structural phase transitions are presented. The open and closed pore phases of DUT-8(Ni) are drastically different in their mechanical behavior. For the open-pore phase, a huge anisotropy of compressibility and shear modulus is observed, caused by the presence of two orthogonal motives formed by aromatic linkers bound with Ni atoms via Ni–O bonds. The possibility of easy shifting of linkers with breaking and formation of new Ni–O and Ni–N bonds at the application of shear stress, which is at the same time more stable at uniaxial stress, is shown on the basis of the stiffness tensor analysis. This fact assumes the flexibility of the open-pore phase crystals and their ability for structural transformation. The less prominent anisotropy of elastic moduli and the increased values of these moduli for the closed-pore phase crystals indicate the predominantly hardness and absence of flexibility of this phase.

Highly efficient and thermostable far-red phosphor for promoting root growth in plants

Ouyang, S., Yin, J., Su, L., (...), Zhang, S., Xia, M.// Journal of Materials Chemistry C//

DOI https://doi.org/10.1039/D3TC02823B

Phytochrome PFR plays a key role in plant photomorphogenesis, and its perception of far-red light is essential, but how to obtain an efficient far-red phosphor to achieve accurate light filling remains a huge challenge. In this study, Gd1−yzAl3−x(BO3)4:xCr3+,yLu3+,zSm3+ (GAB:xCr3+,yLu3+,zSm3+) series phosphors were synthesized by a high-temperature solid-state method. By doping Lu3+, the emission intensity of Cr3+ could increase as high as 20%. With the introduction of Sm3+, the emission intensity of Cr3+ was further increased by 29%. Particularly, the emission spectra can be tuned by varying the concentration ratio of Sm3+ and Cr3+, more suitable for the absorption spectrum of PFR. Moreover, the internal quantum yield and external quantum yield of GL0.1AB:0.03Cr3+ and GL0.1AB:0.03Cr3+,0.003Sm3+ were 83.1% and 24.7% and 78.1% and 26.3%, respectively. There were high anti-thermal quenching properties in the prepared phosphors at 423 K, with 107.6% (GAB:0.03Cr3+), 103.1% (GL0.1AB:0.03Cr3+), and 102.7% (GL0.1AB:0.003Sm3+,0.03Cr3+). Finally, the phosphors were made into pc-LED devices, which can realize the adjustable orange-red and far-red luminescence and meet the needs of plant lighting applications. In the light-regulated plant growth experiment, compared with the control group, far-red light promoted root growth in plants, confirming the application potential of the prepared phosphors in indoor plant cultivation.

Superconducting Order Parameter Structure in the Nematic Phase of Iron-based Materials

Korshunov, M.M., Togushova, Y.N.// JETP Letters//

https://doi.org/10.1134/S0021364024600046

We consider the effect of the nematic order on the formation of the superconducting state in iron pnictides and chalcogenides. Nematic order with the B2g symmetry is modelled as the d-type Pomeranchuk instability and treated within the mean-field approach. Calculated nematic order parameter depends on the nematic interaction coefficient and abruptly changes with the coefficient’s increase. The superconducting solution is obtained within the spin-fluctuation pairing theory. We show that the leading solution in the nematic phase has a sπ± structure. From the critical temperature Tc estimations, we conclude that the nematic superconducting state of the sπ± type is more favorable than the usual s± and ��2−�2 type states appearing in the absence of the nematicity

MODULATION OF LIGHT TRANSMISSION IN SELF-ORGANIZED ENS

Parshin, A.M.// Zhidkie Kristally i Ikh Prakticheskoe Ispol'zovanie

Zhidkie Kristally i Ikh Prakticheskoe Ispol'zovanie, 23(4), pp. 49-57.

Preparation and Properties of Magnetic Composites γ-Fe2O3/SiO2/Aptamer(FAS9) for Magnetic Resonance Hyperthermia

Stolyar, S.V., Li, O.A., Nikolaeva, E.D., (...), Volochaev, M.N., Mokhov, A.A.// Physics of Metals and Metallography//

https://doi.org/10.1134/S0031918X23601439

Powders of maghemite γ-Fe2O3 with an average diameter of 8 nm, γ-Fe2O3/SiO2 composites with an agglomerate diameter of about 50 nm and a size of interspersed γ-Fe2O3 particles of 6 nm, and γ‑Fe2O3/SiO2/aptamer(FAS9) composites were synthesized by chemical deposition. Mössbauer spectra were measured, the static and dynamic magnetic properties of the powders were studied, and the coercive force was determined, which decreases from 14 Oe for γ-Fe2O3 powders to 3 Oe for the γ-Fe2O3/SiO2 composite. It is shown that the particle blocking temperature is close to room temperature. The increment of temperature of the powders was measured in the ferromagnetic resonance mode; the temperature of the Fe2O3/SiO2 composite (ΔT ≈ 16°C) turned out to be higher than that of the pure γ-Fe2O3 powder (ΔT ≈ 10°C). It has been experimentally shown that temperature increment ΔT is proportional to the square of the microwave field amplitude. It has been shown that the composition γ-Fe2O3/SiO2/aptamer FAS9 is able to effectively bind to tumor cells, and FMR hyperthermia leads to a decrease in the viability of tumor cells.

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