Khaptakhanova P., Uspenskii S., Aleksandrov A., Ryzhykau Y., Okhrimenko I.

AbstractIn this study presents a new strategy for the preparation of amphiphilic copolymers of ε‐polylysine (PL) and poly‐L‐lactic acid (PLA) using one‐step pulsed mechanochemical approach. Correlation between the synthesis parameters (ratio of homopolymers) and the structure of the resulting copolymers has been studied. The interaction products were characterized by nuclear magnetic resonance, Infrared spectroscopy, size‐exclusion chromatography, by varying the mass ratio of the initial homopolymers (PL:PLA = 10:90; 50:50; 90:10). It is shown that the largest number of product yield is formed in a ratio of homopolymers of 50:50, according to the reaction of aminolysis of polyesters. The dynamic light scattering method, transmission electron microscopy, and small‐angle x‐ray scattering were used to characterize nanoscale structures of copolymer macromolecules in aqueous solvent. As a result of pulsed mechanochemical action at all three ratios of homopolymers (PL:PLA = 10:90; 50:50; 90:10 w/w), the aminolysis reaction of the ester group occurs and branched macromolecules of copolymers are formed, which consist of chemically related sequences of homopolymers—main chain—PL, side branches—PLA. However, the maximum yield of the amphiphilic copolymer was 90 wt% with a PL:PLA ratio of 50:50. This study can serve as the development of important areas: deepen knowledge in the field of mechanochemical synthesis of amphiphilic copolymers.

Aleksandrov A.I., Shevchenko V.G.

The review examines the effect of radio-frequency superradiance during pulsed mechanochemical activation of polymer composites under high pressure. Mechanochemical activation is implemented in three modes: (a) rheological explosion of polymer composite under rapid uniaxial compression, when an elastic wave pulse occurs in a polymer composite sample and implements the physico-chemical transformations leading to the occurrence of a superradiance pulse; (b) parametric mode, when an elastic wave pulse is introduced from the outside through a waveguide into a composite sample; (c) the mode of rapid pressure release, which also leads to the occurrence of a superradiance pulse. Paramagnetic polymer composites—namely polystyrene–binuclear clusters Co(QH)2–O–Co(QH)2 or Mn(QH)2–O–Mn(QH)2, where QH is a ligand based on QH2–3,6-di-tert-butylpyrocatechin)—are considered as objects implementing such processes. These binuclear clusters exhibit the Dzyaloshinskii–Moriya effect, and polymer composites based on them exhibit multiferroic properties. A composite of a molecular magnet in polystyrene matrix (Eu(III)(SQ)3·bipy complex with four unpaired electrons on Eu(III) and on SQ ligands; SQ is 3,6-di-tert-butylquinolate paramagnetic ligand) is also considered. The binuclear clusters and europium complexes form 2D nano-objects in the polymer matrix with a diameter of 50–100 nm and a thickness of ~ 1–2 nm. The review considers the formalisms of Dicke, Lorentz, Landau–Lifshitz–Blombergen and Havriliak–Negami equations, which make it possible to conduct a time–frequency analysis of these processes, to obtain data on the relaxation processes of spin and charge density in objects responsible for the process of radio-frequency superradiation. It is also shown that the analysis of electron spin resonance data allows us to provide a probable quantum chemical scheme for the implementation of the radio-frequency superradiance process. The phenomenon of superradiation has a great deal of potential in such areas as energy-saving technologies, wireless power transmission and storage devices. The technique of studying fast mechanochemical processes considered in the review allows us to investigate the mechanisms of interaction of magnetic and electrical subsystems in multiferroics and molecular magnets, which expands the scientific base for the creation of new functional materials and enables the solving of related problems of condensed matter physics.

Svishcheva N.B., Uspenskii S.A., Sedush N.G., Khaptakhanova P.A., Kasatova A.I., Buzin A.I., Dmitryakov P.V., Piskarev M.S., Aleksandrov A.I., Taskaev S.Y.

A new strategy for obtaining long-acting fertilizers in the process of joint polycondensation of lactic and boric acids is presented. The article shows the effect of boric acid or boric anhydride additives in an amount of 0.1-1%wt. on the synthesis and final properties of poly(lactic acid). With increase in the amount of boric acid or boric anhydride in poly(lactic acid), polymers show higher T g and T m at approximately equal molecular weights compared to poly(lactic acid) without additives. Comprehensive studies of the structure of the obtained compositions were carried out: theoretical calculations using method DFT (Becke-Lee-Yang-Parr) and experimental - proton NMR, IR spectroscopy and melt rheometry. It has been suggested that the addition of boric acid when heated promotes the formation of B-O-C bonds and the branching of lactic acid oligomer chains. The compositions and the dynamic of boric acid release by granules obtained from boron-containing poly(lactic acid) melts were studied using elemental analysis for aqueous systems. During 7 days of testing in aqueous medium, the granules lose from 16 to 72% of boric acid. This study can serve as further development of the use of low-molecular-weight poly(lactic acid) with different molecular weights in the design of long-acting fertilizers. • Boric acid and boric anhydride were added to a lactic acid during synthesis of poly(lactic acid); • The effect of additives on the thermophysical, molecular-mass and rheological properties of poly(lactic acid) is estimated; • B-O-C bonds are not preserved in polycondensation products; • The results of hydrolysis indicate a prospect of using boric acid-containing poly(lactic acid) as a slow-release fertilizer.

Aleksandrov A.I., Shevchenko V.G., Klyamkina A.N., Nedorezova P.M.

Polymer composite films of polypropylene and graphene nanoplatelets were subjected to mechanical activation . Electrical current pulses are observed during this process. Fourier transforms of the signals are fitted to Havriliak-Negami model and the Kubo model for multilayer graphene. The calculated frequency dependences of conductivity are in good agreement with the experimental results. Relaxation processes and changes in the local geometry of graphene sheets under the influence of elastic waves are responsible for the effects. • Thin films of polypropylene and graphene nanoplatelets are subjected to mechanical activation. • Electrical current pulses are observed. • Fourier transforms of the signals are described by the Kubo model for multilayer graphene.

Aleksandrov A.I., Shevchenko V.G., Aleksandrov I.A., Abramchuk S.S., Degtyarev E.N., Zezin S.B., Fokin S.V., Ovcharenko V.I.

Composites of a heterospin molecular magnet [Eu(III)(SQ)3bipy] in a polystyrene (PS) matrix have been synthesized. The [EuIII(SQ)3bipy] complex contains four paramagnetic centers—the Eu3+ ion and three SQ ligands (SQ-3,6-di-tert-butyl benzoquinone radical anion); bipy (bipyridyl) is diamagnetic. It has been established that intensive mechanical activation of [Eu(III)(SQ)3bipy]/PS samples leads to a rheological explosion, as a result of which radio frequency superradiance, the appearance of free electrons and the formation of Eu metal nanoparticles are observed. The duration of this process is 10 ns.

Aleksandrov A.I., Shevchenko V.G., Klyamkina A.N., Nedorezova P.M., Ozerin A.N.

A phenomenon of change in the frequency of a mechanically activated current was detected for the first time. This phenomenon consists in the fact that electric current pulses produced by a rheological explosion differ in frequency characteristics between a polypropylene‑graphene nanoplates composite and the matrix polymer (polypropylene). It was shown that the Fourier transforms of the current signals from the composite according to the Havriliak–Negami model for the experimental frequency dependence of conductivity agree well with the results of the calculation using the Drude model for multilayer graphene.

Aleksandrov A.I., Shevchenko V.G., Tarasenkov A.N., Surin N.M., Cherkaev G.V., Metlenkova I.Y., Svidchenko E.A., Krasovsky V.G., Dubinsky A.A., Degtyarev E.N.

• One-stage mechanochemical synthesis of a chemically stable nanocluster in dendrimer by the method of mechanoactivation. • The proposed approach greatly simplifies the process of nanostructure synthesis by the guest - host type, reducing it to one stage. • Dendrimer stabilizes the binuclear copper complex with the Dzyaloshinsky-Moriya effect. A novel nanocluster (organosilicon dendrimer - copper dimer) G1–8S-Dec•2CuCl 2 was synthesized by a mechanochemical method. Optical and IR spectroscopy, NMR and ESR methods confirm that mechanochemical action on the mixture (dendrimer G1–8S-Dec + anhydrous copper (II) chloride) leads to the formation of a structure in which two copper atoms are linked by exchange interaction and are stabilized in the form of a dimer by sulfur atoms in the structure of the dendrimer G1–8S-Dec. A quantum mechanical calculation was carried out using the density differential method (DFT), which proved the possibility of the existence of two tetrahedral complexes SCuCl 3 connected by a common face of chlorine atoms and having sulfur atoms at the vertices located in the branches of the dendrimer. The structure of the Cu 2 Cl 4 Si 5 C 116 H 244 S 8 nanocluster is calculated by complete geometry optimization. It was found that the synthesized cluster implements the Dzyaloshinsky - Moriya interaction and exhibits multiferroic properties.

Aleksandrov A.I., Shevchenko V.G., Aleksandrov I.A., Fokin S.V., Ovcharenko V.I.

The effect of mechanical activation of radiofrequency superradiance in a composite based on a heterospin molecular magnet and a polystyrene matrix has been established. Mechanical activation was carried out for the first time in the rheological explosion unloading mode.

Aleksandrov A.I., Shevchenko V.G., Ozerin A.N.

Appearance of the rheological explosion in PE pellets with different molecular weights is investigated. The duration of the first and second stages of the rheological explosion is almost independent of MW. The moment of irreversible destruction of the sample and the value of rheological explosion threshold linearly decrease with an increase in the length of the polymer chain. As a result of the explosion, the heat of melting of polymers with MW values equal to 3 × 105 and 1 × 106 decreases, while for PE with M = 3.5 × 104 the heat of melting remains almost unchanged. Electric current pulses are recorded. Their Fourier images are in the form of band spectra described by the Lorentz models for a damped harmonic oscillator and the Havriliak–Negami model for dielectric relaxation. Experimental data suggest that the rheological explosion is associated with the accumulation of elastic energy in the amorphous phase of PE and, during the rheological explosion, polymer chains are broken to generate radicals •RO2.

Aleksandrov A.I., Aleksandrov I.A., Shevchenko V.G., Ozerin A.N.

Rheological explosion in polymers under uniaxial compression in an open volume occurs at the end of continuous rapid plastic deformation after several stages of creep. Two types of polymers were chosen for this study: brittle glassy amorphous polystyrene and thermoplastic semi-crystalline polypropylene. Electric pulses were detected during explosion, and their spectra were analyzed with two models. X-ray diffraction methods were used to investigate changes in the structure and morphology of polymers during deformation and rheological explosion. The pores appear in polymer in this process, and their shape and size distribution were derived from X-ray experiments. The main reason for the formation of pores in polymer samples in rheological explosion experiments is the intense microshifts in the polymer volume under the action of high applied pressure.

Aleksandrov A.I., Shevchenko V.G., Aleksandrov I.A., Degtyarev E.N., Abramchuk S.S.

A parametric mode of radiofrequency superradiance was found to emerge upon external exposure of a paramagnetic polymer composite to pulses of elastic waves under high pressure. The composite was a polystyrene matrix containing a system of crossed spins on the basis of Co(QH)2–O–Co(QH)2 or Mn(QH)2–O–Mn(QH)2 binuclear clusters (QH is a ligand based on QH2, 3,6-di-tert-butylpyrocatechol), which possess the Dzyaloshinskii–Moriya effect. It was shown that one of the metal atoms of the binuclear cluster in the polystyrene matrix is trapped by the benzene rings of polystyrene by the type of ferrocene. Binuclear clusters form 2D nano-objects with a diameter of 50–100 nm and a thickness of ~1–2 nm. A method for the analysis of these processes and a probable scheme of their emergence are proposed.

Aleksandrov A.I., Shevchenko V.G., Aleksandrov I.A.

The effect of induced mechanical activation of radio-frequency superradiance in a parametric mode under the action of an external rheological explosion at high pressure on a paramagnetic composite—a system of crossed spins based on binuclear complexes Co (QH)2–O–Co(QH)2 or Mn(QH)2–O–Mn(QH)2 (QH is a ligand based on 3,6-di-tert-butylpyrocatechol) in a polystyrene matrix—is found. Possible methods for processing data on the pulsed mechanical effect and a possible scheme of the initiation of the effect are proposed.

Aleksandrov A.I., Shevchenko V.G., Aleksandrov I.A., Tebeneva N.A., Meshkov I.B., Kalinina A.A., Degtyarev E.N., Dubinskii A.A., Kovarsky A.L., Zezin S.B., Krasovskii V.G., Abramchuk S.S., Buzin M.I., Muzafarov A.M.

Aleksandrov A.I., Shevchenko V.G., Aleksandrov I.A.

A magnetoelectric effect was discovered in polystyrene/organoelemental binuclear cobalt complexes with ligands of spatially hindered phenols at room temperature. The Dzyaloshinskii–Moriya interaction (dipole–dipole and anisotropic exchange interaction of unpaired electrons on cobalt ions at 77 K and room temperature) is fulfilled in such complexes. A novel class of high-temperature multiferroics—polymer composites—can be produced on the basis of such molecular structures.

Aleksandrov A.I., Tebeneva N.A., Shevchenko V.G., Aleksandrov I.A., Meshkov I.B., Muzafarov A.M.

A new class of high-temperature multiferroics has been created. They are polymer composites based on a polystyrene matrix and nucleus–shell nanoparticles, where the nucleus consists of silica nanoparticles and the shell consists of Fe(III) spin-variable ions.

Gette M.S., Sudarev V.V., Osipov S.D., Laptenkova E.V., Bazhenov S.V., Zagryadskaya Y.A., Tilinova O.M., Dronova E.A., Kuklina D.D., Al Ebrahim R., Fedorov D.M., Kurkin T.S., Semenov Y.S., Bondarev N.A., Skoi V.V., et. al.

Chereddy T., Miriyala V.S., Lakkimsetty N.R., Suragani S., Miriyala N.L., Kotcharla H.R.

Qiu C., Liu Z., Rao Q., Yang H., He Y., Li D., Zhong Y., Lin J., Li H., Huang G., Lin H., Shen J., Zhang X., Zhang Z., Wang X., et. al.

The serious combination of abundant electrons/holes in bulk primarily hinders the efficiency in the photocatalytic reaction. It is crucial to control the spatial charge dynamics through delicately designing the crystal configuration of photocatalyst. In this work, a modified tungsten trioxide nanosheet colloid (M-WO

Александров А.И., Ткачев В.В., Шевченко В.Г., Озерин А.Н., Роговина С.З., Берлин А.А.

Двумя независимыми методами в твердой фазе под действием сдвиговых деформаций и жидкофазным методом в хлороформе получены композиции полилактид–восстановленный оксид графена разного состава. Обнаружен эффект изменения частоты механически активированного тока, заключающийся в том, что импульсы электрического тока, возникающие при быстром разрушении типа реологического взрыва, отличаются по частотным характеристикам для полилактида и его композиций с восстановленным оксидом графена. Продемонстрировано различие релаксационных характеристик их частотных спектров, соответствующих наблюдаемым процессам переноса заряда.

Figueira M., Srivastava V., Reig M., Valderrama C., Lassi U.

Boron (B) is a crucial element for efficient plant growth and development; therefore, B-based fertilisers have been employed in agricultural applications. The need for B-based fertilisers for agricultural uses is continuously increasing as a result of the world's growing population. It is expected that the global market for B-based fertiliser will grow by around $6.3 billion by 2032; hence, demand for B sources will also increase. In addition to being used in fertiliser, B is also employed in the production of neodymium iron B (NdFeB) permanent magnets. The demand for NdFeB magnets is also continuously increasing. Hence, it is of the utmost importance to reclaim B from secondary resources due to the rising demand for B in a wide variety of applications. This review study addresses the recovery of B from various waste streams. The main focus is on the recovery of B from spent NdFeB magnets, borax sludge, and liquid streams such as brine water, seawater, sewage, industrial wastewater, and agricultural effluents. Different technologies for B recovery are discussed, such as sorption, solvent extraction, membrane processes, precipitation, and hydrometallurgical methods. Solvent extraction has been found to be a very effective approach for reclaiming B from spent NdFeB magnet waste and from liquid streams with high B concentration (>1-2 g/L). Further, the application of B-based fertiliser in agriculture application is reviewed. Challenges associated with B recovery from waste streams and future perspectives are also highlighted in this review.

Silva A., Hurdley F., de Oliveira A.L., Slater T., da Silva Maia A., Folli A., dos Santos I.M.

The use of the wide band gap SrSnO3 semiconductor in photocatalysis has grown over the last few years, driven predominantly by sustainability given that its constituents are all Earth abundant elements. Using EPR spectroscopy, we elucidate the paramagnetic species present in the material, either intrinsic or photo-generated. EPR measurements confirmed the presence of paramagnetic oxygen vacancies (g = 2.0058) and a defect sensitive to visible light irradiation despite a wide optical band gap of 4.1 eV. This defect was confirmed to be Sn3+ (g = 2.014 and g = 1.994). Its concentration appears to increase with visible light irradiation, suggesting a photo-induced formation associated with electronic transitions from Sn2+ intra-band gap states to the conduction band.

Liu Y., Wang T., Yang J., Yu T., Liao Q.

We study the superradiance and entanglement phenomena between two quantum emitters (QEs) operating at terahertz (THz) frequencies, facilitated by the presence of a topological insulator bismuth selenide (Bi2Se3). Controlled by the hyperbolic phonon polaritons and electron surface state in the terahertz (THz) frequency range, the interaction between QEs is significantly enhanced both within and outside the hyperbolic bands. Moreover, the entanglement between two QEs through Bi2Se3 is studied in detail. Certain initial entanglement states undergo sudden death of entanglement when the system is in non-interaction. However, in the cases of moderate or strong interaction, the entanglement can be revive after experiencing the sudden death phenomenon. These findings hold significant implications for controlling the interaction of QEs and their potential applications in the fields of quantum metrology and quantum imaging in the THz frequency region.

Ghosh T.

Abstract: Research on novel discotic molecules, which consist of a rigid core with flexible peripheral chains, has gained much attention due to their crucial role as organic photovoltaic materials, organic field-effect transistors, and semiconductors for photocurrent generation, as well as the possibility of their other optoelectronic applications. This review article describes the developments in fundamental design ideas and synthetic approaches of porphyrin-based meso and beta-substituted liquid crystals. In addition, the current review highlights the various structural alterations made by the researchers in the field of porphyrin-based mesogens and changes in properties, both for materials intended for commercially successful liquid crystal displays, including other applications, and for more basic purposes of demonstrating structure-property relationships.

Easwaran C., Christopher S.R., Moorthy G., Mohan P., Marimuthu R., Koothan V., Nallusamy S.

The advent of Nanohybrid (NH) fertilizers represents a groundbreaking advancement in the pursuit of precision and sustainable agriculture. This review abstract encapsulates the transformative potential of these innovative formulations in addressing key challenges faced by modern farming practices. By incorporating nanotechnology into traditional fertilizer matrices, nanohybrid formulations enable precise control over nutrient release, facilitating optimal nutrient uptake by crops. This enhanced precision not only fosters improved crop yields but also mitigates issues of over-fertilization, aligning with the principles of sustainable agriculture. Furthermore, nanohybrid fertilizers exhibit the promise of minimizing environmental impact. Their controlled release mechanisms significantly reduce nutrient runoff, thereby curbing water pollution and safeguarding ecosystems. This dual benefit of precision nutrient delivery and environmental sustainability positions nanohybrid fertilizers as a crucial tool in the arsenal of precision agriculture practices. The intricate processes of uptake, translocation, and biodistribution of nutrients within plants are examined in the context of nanohybrid fertilizers. The nanoscale features of these formulations play a pivotal role in governing the efficiency of nutrient absorption, internal transport, and distribution within plant tissues. Factors affecting the performance of nanohybrid fertilizers are scrutinized, encompassing aspects such as soil type, crop variety, and environmental conditions. Understanding these variables is crucial for tailoring nanohybrid formulations to specific agricultural contexts, and optimizing their impact on crop productivity and resource efficiency. Environmental considerations are integral to the review, assessing the broader implications of nanohybrid fertilizer application. This review offers a holistic overview of nanohybrid fertilizers in precision and sustainable agriculture. Exploring delivery mechanisms, synthesis methods, uptake dynamics, biodistribution patterns, influencing factors, and environmental implications, it provides a comprehensive understanding of the multifaceted role and implications of nanohybrid fertilizers in advancing modern agricultural practices.

Liubimovskii S.O., Novikov V.S., Vasimov D.D., Kuznetsov S.M., Sagitova E.A., Dmitryakov P.V., Bakirov A.V., Sedush N.G., Chvalun S.N., Moskovskiy M.N., Nikolaeva G.Y.

We carried out a Raman study of a series of poly(L-lactide) (PLLA) samples annealed for different periods of time and therefore having different crystallinity degree. We compared the results with our recent study of the series of poly(L-lactide-co-ε-caprolactone) (PLCL) copolymers with the ε-caprolactone (CL) content ranging from 5 to 30 mol %. X-ray diffraction (XRD) analysis showed that the crystallinity degree of the analyzed PLLA-based materials is in the range of 0–86%. We suggest using the ratio of the peak intensities of the PLLA Raman bands at 411 and 874 cm–1 to evaluate the crystallinity degree of PLLA homopolymers as well as PLLA blocks in the PLCL copolymers. This ratio does not depend on the CL content in the copolymers, it strongly depends on the crystallinity degree of PLLA (PLLA blocks in the PLCL copolymers) and it is a linear function of the crystallinity degree, measured by XRD analysis. We carried out quantum chemical calculations of the optimized geometries and Raman spectra of PLLA oligomers in the conformation of helix 103 with the number of monomeric units from 5 to 12. The results of the calculations revealed that the ratio of the intensities of the bands at 411 and 874 cm–1 weakly depends on the oligomer length for the number of the PLLA monomeric units more than 7.

Osmanova S.N., Suleymanova S.A., Zeynalova T.G., Ismailov E.H.

Jiang Z., Zhang Z., Xia B., Xiong S., Yang L., Li Z.

The separation of boron isotopes poses significant challenges due to their similar chemical properties. Previous studies have demonstrated that boron isotope separation can be achieved by solvent extraction of boric acid (H3BO3) using trioctylamine (TOA) and tartaric acid (DL-TA), resulting in a remarkable separation factor of up to 1.04 through chemical exchange. However, the coordination mechanism among these three compounds remains elusive, impeding our understanding of the isotope exchange process. In this study, the species in the aqueous and organic phases were investigated using extraction experiments (maximum loading method), alongside various characterization techniques (FT-IR, 11B NMR, and high-resolution ESI-MS), followed by DFT computations. The results showed that H3BO3 and DL-TA formed anionic complexes in the aqueous phase with stoichiometric ratios of 1:1 and 1:2, respectively. However, the stoichiometric ratios became more intricate in the organic phase, encompassing 1:1, 1:2, 2:2, 2:3, and 3:3. The average stoichiometric ratio of H3BO3 to DL-TA calculated within the range of 1:1 to 1:1.5. Protonated TOA could form ion pairs with these anionic complexes, while unprotonated TOA might form hydrogen bonds with the carboxyl groups in DL-TA, contributing to the complexity of the stoichiometric ratios between H3BO3 and TOA. The DFT calculations indicated that all complexes containing B(4)–O bonds, including 1:1, 1:2, 2:2, 2:3, and 3:3, effectively facilitated the exchange of isotopes with H3BO3. These findings pave the way to process optimization of boron isotope separation by solvent extraction of boric acid.

Chen F., Zhou Z., Zhang J., Feng C.

Abstract Local structures and electron paramagnetic resonance (EPR) parameters (g factors g x , g y , and g z ) for the substitutional Ti3+ and W5+ centers in stishovite are theoretically investigated by using the high-order perturbation formulas of these parameters for a d1 ion in rhombically compressed octahedra. In the calculation formulas, the related molecular orbital coefficients are obtained from the cluster approach, and the relevant crystal-field (CF) parameters are determined from the superposition model, which enables to connect these CF parameters and, hence, the studied g factors with the local structures of the Ti3+ and W5+ centers in stishovite. Based on the calculations, the impurity–ligand bond lengths parallel and perpendicular to the C 2-axis are found to be R′|| (≈1.751 and 1.717 Å) and R′⊥ (≈1.788 and 1.806 Å) with the planar bond angles θ′ (≈89.0° and 88.2°) for the studied [TiO6]9− and [WO6]7− clusters, respectively. The calculated results are in good agreement with the experimental data, and the validity of the results is discussed.

Lyagushyn S., Sokolovsky A.

Spontaneous ordering in a system of excited emitters with a powerful short radiation pulse predicted by Dicke attracted the great attention of scientists for decades as a bright example of the nontrivial behavior of a nonequilibrium system. The Bogolyubov reduced description method has some advantages and provides new possibilities in the theoretical investigation of the Dicke process. The paper presents the authors’ results of modeling such processes concerning both optical ones in the presence of crystal lattice influence and acoustic superradiance, which is possible in solids. The right choice of reduced description parameters allows the account of atom motions (phonons), cavity influence, and excitations in the emitter system (excitons) in the electromagnetic radiation process. The mathematical analogy between the Dicke system and a spin system in a magnetic field opens the way to applying the reduced description technique to acoustic phenomena previously investigated with the boson variable elimination method. Such a new approach to superradiance in crystals with paramagnetic impurities and with competing mechanisms of relaxation (Wagner model) is outlined. Acoustic superradiance is discussed in connection with the problem of structural phase transitions.

Pozdnyakov A., Kuznetsova N., Ivanova A., Bolgova Y., Semenova T., Trofimova O., Prozorova G., Emel'yanov A.

New functional heat-resistant poly (1-vinyl-1,2,4-triazole-co-triethoxyvinylsilane) (poly (VT-co-TEVS)) copolymers of various compositions containing triazole and triethoxysilyl groups in the side chains were synthesized by radical copolymerization. Elemental analysis, Fourier transform infrared spectroscopy, NMR spectroscopy, gel permeation chromatography, dynamic light scattering, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry were used to study the composition and structure of poly (VT-co-TEVS) copolymers. The weight average molecular weight of the copolymers varies from 21 to 174 kDa. The reactivity ratios of comonomers in copolymerization (rVT = 4.004 and rTEVS = 0.227) indicate the high reactivity of VT. The resulting copolymers exhibit high thermal stability up to 270 °C. Modification of flexible chain poly (VT-co-TEVS) copolymers was carried out using hydrolytic polycondensation of triethoxysilyl groups. Monitoring of the hydrodynamic diameters of the synthesized copolymers showed intermacromolecular crosslinking of polymer chains due to the formation of Si–O–Si siloxane bonds. Based on spatially cross-linked polyorganosiloxanes containing a functional 1,2,4-triazole fragment, hydrophobic heat-resistant polymeric materials were obtained.

Salahshoori I., Golriz M., A. L. Nobre M., Mahdavi S., Eshaghi Malekshah R., Javdani-Mallak A., Namayandeh Jorabchi M., Ali Khonakdar H., Wang Q., Mohammadi A.H., Masoomeh Sadat Mirnezami S., Kargaran F.

Efficient drug delivery systems (DDSs) play a pivotal role in ensuring pharmaceuticals' targeted and effective administration. However, the intricate interplay between drug formulations and delivery systems poses challenges in their design and optimization. Simulations have emerged as indispensable tools for comprehending these interactions and enhancing DDS performance to address this complexity. This comprehensive review explores the latest advancements in simulation techniques for drug delivery systems and provides a detailed analysis. The review encompasses various simulation methodologies, including molecular dynamics (MD), Monte Carlo (MC), finite element analysis (FEA), computational fluid dynamics (CFD), density functional theory (DFT), machine learning (ML), and dissipative particle dynamics (DPD). These techniques are critically examined in the context of drug delivery research. The article presents illustrative case studies involving liposomal, polymer-based, nano-particulate, and implantable DDSs, demonstrating the influential role of simulations in optimizing these systems. Furthermore, the review addresses the advantages and limitations of simulations in drug delivery research. It also identifies future directions for research and development, such as integrating multiple simulation techniques, refining and validating models for greater accuracy, overcoming computational limitations, and exploring applications of simulations in personalized medicine and innovative DDSs. Simulations employing various techniques like MD, MC, FEA, CFD, DFT, ML, and DPD offer crucial insights into drug behaviour, aiding in DDS design and optimization. Despite their advantages, including rapid and cost-effective screening, simulations require validation and addressing computational limitations. Future research should focus on integrating techniques, refining models, and exploring personalized medicine applications to enhance drug delivery outcomes. This paper underscores the indispensable contribution of simulations to drug research and development, emphasizing their role in providing valuable insights into drug behaviour, facilitating the development and optimization of DDSs, and ultimately enhancing patient outcomes. As we continue to explore and enhance simulation techniques, their impact on advancing drug discovery and improving DDSs is expected to be profound.

Ryzhykau Y.L., Povarova O.I., Dronova E.A., Kuklina D.D., Antifeeva I.A., Ilyinsky N.S., Okhrimenko I.S., Semenov Y.S., Kuklin A.I., Ivanovich V., Fonin A.V., Uversky V.N., Turoverov K.K., Kuznetsova I.M.

In addition to the well-known monomeric globular (G-) and polymeric fibrillar (F-) forms, actin can exist in the so-called inactivated form (I-actin). Hsp70 chaperon, prefoldin, and CCT chaperonin are required to obtain native globular state. In contrast, I-actin is spontaneously formed in the absence of intracellular folding machinery. I-actin can be obtained from G-actin by elimination of divalent ion, incubation in presence of small concentrations of denaturants, and by heat exposure. Since G-actin is a quasi-stationary, thermodynamically unstable form, it can gradually transform into inactivated state in the absence of chelating/denaturating agents or heat exposure, but the transition is much slower. I-actin was shown to associate into oligomers up to the molecular weight of 14–16 G-actin monomers, though the structure of these oligomers remains uncharacterized. This study employs small-angle X-ray scattering to reveal novel insights into the oligomerization process of such spontaneously formed inactivated actin. These oligomers are differentiated from F-actin through comparative analysis, highlighting a unique oligomerization pathway.

Sudarev V.V., Gette M.S., Bazhenov S.V., Tilinova O.M., Zinovev E.V., Manukhov I.V., Kuklin A.I., Ryzhykau Y., Vlasov A.V.

Ferritin is a universal protein complex responsible for iron perception in almost all living organisms and has applications from fundamental biophysics to drug delivery and structure-based immunogen design. Different platforms based on ferritin share similar technological challenges limiting their development – control of self-assembling processes of ferritin itself as well as ferritin-based chimeric recombinant protein complexes. In our research, we studied self-assembly processes of ferritin-based protein complexes under different expression conditions. We fused a ferritin subunit with a SMT3 protein tag, a homolog of human Small Ubiquitin-like Modifier (SUMO-tag), which was taken to destabilize ferritin 3-fold channel contacts and increase ferritin-SUMO subunits solubility. We first obtained the octameric protein complex of ferritin-SUMO (8xFer-SUMO) and studied its structural organization by small-angle X-ray scattering (SAXS). Obtained SAXS data correspond well with the high-resolution models predicted by AlphaFold and CORAL software of an octameric assembly around the 4-fold channel of ferritin without formation of 3-fold channels. Interestingly, three copies of 8xFer-SUMO do not assemble into 24-meric globules. Thus, we first obtained and structurally characterized ferritin-based self-assembling oligomers in a deadlock state. Deadlock oligomeric states of ferritin extend the known scheme of its self-assembly process, being new potential tools for a number of applications. Finally, our results might open new directions for various biotechnological platforms utilizing ferritin-based tools.

Osipov S.D., Ryzhykau Y.L., Zinovev E.V., Minaeva A.V., Ivashchenko S.D., Verteletskiy D.P., Sudarev V.V., Kuklina D.D., Nikolaev M.Y., Semenov Y.S., Zagryadskaya Y.A., Okhrimenko I.S., Gette M.S., Dronova E.A., Shishkin A.Y., et. al.

F-type ATP synthases play a key role in oxidative and photophosphorylation processes generating adenosine triphosphate (ATP) for most biochemical reactions in living organisms. In contrast to the mitochondrial FOF1-ATP synthases, those of chloroplasts are known to be mostly monomers with approx. 15% fraction of oligomers interacting presumably non-specifically in a thylakoid membrane. To shed light on the nature of this difference we studied interactions of the chloroplast ATP synthases using small-angle X-ray scattering (SAXS) method. Here, we report evidence of I-shaped dimerization of solubilized FOF1-ATP synthases from spinach chloroplasts at different ionic strengths. The structural data were obtained by SAXS and demonstrated dimerization in response to ionic strength. The best model describing SAXS data was two ATP-synthases connected through F1/F1′ parts, presumably via their δ-subunits, forming “I” shape dimers. Such I-shaped dimers might possibly connect the neighboring lamellae in thylakoid stacks assuming that the FOF1 monomers comprising such dimers are embedded in parallel opposing stacked thylakoid membrane areas. If this type of dimerization exists in nature, it might be one of the pathways of inhibition of chloroplast FOF1-ATP synthase for preventing ATP hydrolysis in the dark, when ionic strength in plant chloroplasts is rising. Together with a redox switch inserted into a γ-subunit of chloroplast FOF1 and lateral oligomerization, an I-shaped dimerization might comprise a subtle regulatory process of ATP synthesis and stabilize the structure of thylakoid stacks in chloroplasts.

Zhu H., Liu R., Shang Y., Sun L.

• This review summarized the advanced development of the synthesis strategies of PLL • This review introduces the biomedical fields, where PLL are mainly utilized, such as cargo delivery, tissue adhesives, and antibacterial materials • The design and synthesis of various PLL-derived complexes can be further optimized for diverse disease treatments Poly-L-lysine (PLL) is a water-soluble biopolymer consist of repeating unit of L-lysine. It displays intrinsic non-antigenicity, antibacterial property, biocompatibility, and biodegradability, and facile synthesis procedure, therefore has attracted particular attention in various biomedical and pharmaceutical applications. Following a brief introduction to PLL synthesis, this review focuses on the significant advances of PLL and PLL-derived complexes utilized in cargo delivery, tissue adhesives, and antibacterial materials. Meanwhile, this review summarized the modification and optimization of PLL complexes for further clinical translational studies. The final section discusses the challenges and opportunities of PLL-based complexes in the biomedical areas.

Aleksandrov A.I., Shevchenko V.G., Tarasenkov A.N., Surin N.M., Cherkaev G.V., Metlenkova I.Y., Svidchenko E.A., Krasovsky V.G., Dubinsky A.A., Degtyarev E.N.

• One-stage mechanochemical synthesis of a chemically stable nanocluster in dendrimer by the method of mechanoactivation. • The proposed approach greatly simplifies the process of nanostructure synthesis by the guest - host type, reducing it to one stage. • Dendrimer stabilizes the binuclear copper complex with the Dzyaloshinsky-Moriya effect. A novel nanocluster (organosilicon dendrimer - copper dimer) G1–8S-Dec•2CuCl 2 was synthesized by a mechanochemical method. Optical and IR spectroscopy, NMR and ESR methods confirm that mechanochemical action on the mixture (dendrimer G1–8S-Dec + anhydrous copper (II) chloride) leads to the formation of a structure in which two copper atoms are linked by exchange interaction and are stabilized in the form of a dimer by sulfur atoms in the structure of the dendrimer G1–8S-Dec. A quantum mechanical calculation was carried out using the density differential method (DFT), which proved the possibility of the existence of two tetrahedral complexes SCuCl 3 connected by a common face of chlorine atoms and having sulfur atoms at the vertices located in the branches of the dendrimer. The structure of the Cu 2 Cl 4 Si 5 C 116 H 244 S 8 nanocluster is calculated by complete geometry optimization. It was found that the synthesized cluster implements the Dzyaloshinsky - Moriya interaction and exhibits multiferroic properties.

Khaptakhanova P.A., Svishcheva N.B., Kurkin T.S., Uspenskii S.A.

A method developed for producing composites based on polylactic acid (PLA) and elemental boron nanoparticles by the method of solid-state polycondensation is presented. The synthesis parameters (time, temperature, and residual pressure) were optimized to obtain PLA with desired properties. The influence of the nanosized boron filler was evaluated. When boron nanoparticles are added in an amount of 0.03 wt.%, the properties of PLA change: the degree of crystallinity increases by 20% compared to the polymer without additives and an increase in the molecular weight of the polymer up to 60 kDa is observed. The properties of the solid-state polycondensation products were studied by NMR spectroscopy, X-ray phase analysis, gel-permeation chromatography, and differential scanning calorimetry.

Svishcheva N.B., Khaptakhanova P.A., Kasatov D.A., Uspenskii S.A.

The method for the synthesis of a composition based on polylactic acid (PLA) and containing boric acid (BA) was proposed. The results of gravimetric analysis of granules formed from this composition after hydrolysis in aqueous solutions are presented. The uniform distribution of boric acid or its covalently linked fragments in the polymer bulk was confirmed by elemental analysis. The tests in water of the composition samples as plates showed that the presence of boric acid or its fragments favored the faster mass loss of PLA and the introduction of ∼3% BA accelerated the mass loss by approximately 5 times. The boron-containing polymeric compositions can find use in agriculture as nutritional additives for seedlings and fruit-bearing crops and to eliminate the lack of boron in boron-deficient soils.

Kaavessina M., Distantina S., Shohih E.N.

In this research, a low molecular weight poly(lactic acid) (or PLA) synthesized from direct polycondensation was melt compounded with urea to formulate slow-release fertilizer (SRF). We studied the influence of the molecular weight (MW) of PLA as a matrix and the urea composition of SRF towards release kinetics in water at 30 °C. The physical appearance of solid samples, the change in urea concentration, and acidity (pH) of water were monitored periodically during the release test. Three studied empirical models exhibited that diffusion within the matrix dominated the urea release process, especially when the release level was less than 60%. Thus, a lower MW of PLA and a higher urea content of SRF showed a faster release rate. For the entire length of the release experiment, a combination of diffusion and degradation mechanisms exhibited the best agreement with the experimental data. The hydrolytic degradation of PLA may begin after 96 h of immersion (around 60% release level), followed by the appearance of some micro-holes and cracks on the surface of the SRF samples. Generally, this research revealed the good release performance of urea without residues that damage the soil structure and nutrient balance.

Solares-Briones M., Coyote-Dotor G., Páez-Franco J.C., Zermeño-Ortega M.R., de la O Contreras C.M., Canseco-González D., Avila-Sorrosa A., Morales-Morales D., Germán-Acacio J.M.

Mechanochemistry is considered an alternative attractive greener approach to prepare diverse molecular compounds and has become an important synthetic tool in different fields (e.g., physics, chemistry, and material science) since is considered an ecofriendly procedure that can be carried out under solvent free conditions or in the presence of minimal quantities of solvent (catalytic amounts). Being able to substitute, in many cases, classical solution reactions often requiring significant amounts of solvents. These sustainable methods have had an enormous impact on a great variety of chemistry fields, including catalysis, organic synthesis, metal complexes formation, preparation of multicomponent pharmaceutical solid forms, etc. In this sense, we are interested in highlighting the advantages of mechanochemical methods on the obtaining of pharmaceutical cocrystals. Hence, in this review, we describe and discuss the relevance of mechanochemical procedures in the formation of multicomponent solid forms focusing on pharmaceutical cocrystals. Additionally, at the end of this paper, we collect a chronological survey of the most representative scientific papers reporting the mechanochemical synthesis of cocrystals.

Yin X., Hewitt D.R., Zheng B., Quah S.P., Stanley C.B., Grubbs R.B., Bhatia S.R.

We report on the nanoscale assembly of poly(lactic acid)- b- poly(ethylene oxide)- b- poly(lactic acid) (PLA-PEO-PLA) triblock copolymers in water, focusing on the effect of stereochemistry, where the PLA blocks are statistical copolymers of l -lactide and d -lactide with l/d ratios of 100/0, 95/5, 90/10, 85/15, 75/25, and 50/50. Small-angle neutron scattering (SANS) shows a nearly constant d -spacing as concentration varies in triblock systems with l/d ratios of 90/10 and 95/5, which we attribute to inhomogeneity in the structure of these gels, supported by previous USANS and confocal microscopy studies. The SANS data fit well to a core-shell ellipsoid form factor model with a hard-sphere structure factor. Polymeric micelles with l/d ratios from 75/25 to 85/15 displayed very high aggregation numbers, consistent with a strong interaction between PLA chains and the enhanced storage modulus observed in rheological studies of these systems. While the 90/10 and 95/5 samples showed lower aggregation numbers, their SANS profiles shows close spacing between micelles, which may promote a high fraction of intermicellar bridging chains, also consistent with a higher storage modulus. Overall, these results provide insight into the micellar assembly behavior of block copolymers with a crystallizable block, and indicate that tuning stereochemistry of PLA-based block copolymers is an effective means of modifying micellar properties for specific applications. • Assembly of block copolymer gels with varying block stereochemistry was explored. • SANS shows a nearly constant d -spacing with concentration for intermediate l/d ratios. • Profiles are consistent with inhomogeneity in the gel structure. • Data also suggest a high fraction of bridging chains at intermediate l/d ratios. • Results give insight into the unique rheology observed in these systems.

Perin F., Motta A., Maniglio D.

The request of new materials, matching strict requirements to be applied in precision and patient-specific medicine, is pushing for the synthesis of more and more complex block copolymers. Amphiphilic block copolymers are emerging in the biomedical field due to their great potential in terms of stimuli responsiveness, drug loading capabilities and reversible thermal gelation. Amphiphilicity guarantees self-assembly and thermoreversibility, while grafting polymers offers the possibility of combining blocks with various properties in one single material. These features make amphiphilic block copolymers excellent candidates for fine tuning drug delivery, gene therapy and for designing injectable hydrogels for tissue engineering. This manuscript revises the main techniques developed in the last decade for the synthesis of amphiphilic block copolymers for biomedical application. Strategies for fine tuning the properties of these novel materials during synthesis are discussed. A deep knowledge of the synthesis techniques and their effect on the performance and the biocompatibility of these polymers is the first step to move them from the lab to the bench. Current results predict a bright future for these materials in paving the way towards a smarter, less invasive, while more effective, medicine. • Amphiphilic block copolymers: available synthesis routes and their advantages and disadvantages • Increased degree of complexity in polymer microstructures by combining synthesis techniques • Strategies to fine tune the properties of amphiphilic block copolymers • Biomedical applications: drug delivery, cancer treatment, tissue engineering, injectable hydrogels, imaging

Chernysheva D.V., Leontyev I.N., Avramenko M.V., Lyanguzov N.V., Grebenyuk T.I., Smirnova N.V.

A NiO/graphene nanocomposite has been prepared via one step electrochemical synthesis using simultaneous pulse alternating current dispersion of both Ni electrode and an electrode of thermally expanded graphite. Electron microscopy and Raman spectroscopy data reveals that the composite consists of graphene sheets with 2–5 layers having 0.5–2 μm size as well as NiO sheets with 200–250 nm dimensions comprising NiO nanoparticles of ∼3.6 nm diameter. The electrochemical capacitance of the nanocomposite is 825 F g−1, with retaining 89% of the initial value after 1000 operation cycles.

Monakhova K.Z., Bazhenov S.L., Kechek’yan A.S., Meshkov I.B.

The effect of particle size on the mechanical characteristics of biaxially oriented composite polypropylene/SiO2 is studied. The material is oriented in plane by squeezing two lead-tin alloy plates with the composite film being placed between them. Deformation is defined by the composition of the plates. This makes it possible to obtain the material with low degrees of orientation. The oriented composite preserves plasticity typical of the polypropylene matrix. After biaxial orientation of the unfilled PP, the yield point decreases by approximately 40% upon subsequent stretching. A reduction in the size of particles changes their adhesion behavior during stretching. Coarse particles with a size of about 20 µm separate from PP during stretching. On the contrary, nanoparticles with sizes of 200 and 500 nm do not separate even under plastic deformation of the composite. As a result, nanoparticles reinforce the thermoplastic the same way as carbon black nanoparticles reinforce rubber. The energy detachment criterion explaining an increase in the detachment stress with decreasing particle size is derived.

Mashchenko V.I., Sitnikov N.N., Khabibullina I.A., Chausov D.N., Shelyakov A.V., Spiridonov V.V.

Borosiloxane materials obtained by mixing and thermostatting of hydroxyl-terminated polydimethylsiloxane and boric acid are studied. Samples synthesized at room temperature and at a temperature above 220°С are nontransparent rubberlike masses. Washing of boric acid yields single-phase transparent borosiloxanes demonstrating the rubberlike behavior. Studies are carried out using elemental analysis, dynamic light scattering, synchronous thermal analysis, and polarization optical microscopy. The viscoelastic properties of the samples are characterized by rheological methods and the ability of polymer ball-like samples to spread and rebound. It is shown that in initial states they contain boric acid microcrystalline inclusions that scatter visible light. An increase in the synthesis temperature and the presence of unreacted boric acid improve the elasticity of the materials and decrease their thermal stability. The content of boron in borosiloxane obtained at an increased temperature is an order of magnitude higher than that in borosiloxane synthesized at room temperature, whereas the radius of the effective hydrodynamic sphere is smaller by a factor of 5 than that in the high-temperature borosiloxane. The rheological properties of the tested samples are different. These materials show promise as components of multilayer self-healing and shock-absorbing composites and materials with controlled tackiness.