The structure and surface morphology of the BaF2/Al2O3( 01̅12 ) and BaF2/CaF2/Al2O3( 01̅12 ) dielectric buffer layers obtained by molecular beam epitaxy are studied for use as substrates for radiation-resistant matrix photodetector devices based on AIVBVI compounds.
The effect of KF doping (5 mol P3̅c1 ) and Pb1–xCdxF2 with the fluorite structure (sp. gr. Fm3̅m ) was studied. Powder samples of 95(Pr0.9Pb0.05F2.95)·5KF and 95(Pb0.67Cd0.33F2)·5KF (mol
A combined approach is proposed for the design of oxygen reduction reaction (ORR) catalysts based on bimetallic PtCu nanoparticles and nitrogen-doped carbon supports (Vulcan XC-72, KetjenBlack EC-600JD). Nitrogen doping of KetjenBlack increases the mass activity in ORR to 1261 A/g(Pt), which is 4.9 times higher than that of the commercial Pt/C (HiSPEC3000) counterpart. Transmission electron microscopy revealed improved dispersion and uniform distribution of bimetallic nanoparticles. Stress testing confirmed the high stability of PtCu/KetjenBlack-N, retaining >80
Memristive Ti/HfOx/Au/c-Si structures have been studied, in which a hafnium oxide layer was deposited by magnetron sputtering of a Hf target at various oxygen partial pressures in the chamber. The optimal gas mixture composition was selected to fabricate memristors with highly stable resistive switching. The resulting structures are characterized by high plasticity, energy efficiency, and low cycle-to-cycle and device-to-device variation of the switching voltage, making them promising for various neuromorphic applications.
As a result of the analysis of modern achievements in the field of thermoelectric materials science, the compositions, doping and methods for obtaining effective thermoelectric materials based on n-type Bi2Te3–Bi2Se3 and p-type Bi2Te3–Sb2Te3 with operating temperatures from 300 to 600 K were established. Key ways to increase their thermoelectric figure of merit have been identified. In this temperature range, the maximum thermoelectric figure of merit for n-type materials is 1.32 and the average is 1.20, while for p-type materials, these values are 1.60 and 1.30, respectively. These materials exhibit satisfactory mechanical strength, which is necessary for fabricating thermoelement legs. It has been established that maximum efficiency and, accordingly, high efficiency in the operating temperature range can be achieved using two-section legs in thermoelements.
Nanocrystalline (10–14 nm) powders of concentrated solid solutions of Pb1–xRxF2+x (R = La, Pr, Nd) with a fluorite structure were synthesized using the coprecipitation technique from aqueous solutions of nitrates. The ionic conductivity of ceramic samples based on them (85 ± 2
Uromodulin, a key glycoprotein in human urine, plays a crucial role in maintaining urinary tract homeostasis by forming supramolecular structures that influence urine’s rheological properties. This study investigates the effect of uromodulin on both macroscopic (viscosity) and microscopic (nanoparticle mobility) characteristics of solutions, using small-angle X-ray scattering (SAXS), nanoparticle tracking analysis (NTA), and viscometry. Our results reveal that uromodulin forms a dynamic polymer network with distinct structural elements: a central filament (2.7 nm), side chains (8.9 nm), and network cells ( 28 nm at 5 g/L). While macroscopic viscosity remains unchanged in dilute solutions (0.004–1 g/L), uromodulin significantly restricts the mobility of nanoparticles (32–150 nm) in a size- and concentration-dependent manner, with effects becoming more pronounced at protein concentrations above 0.05 g/L. These findings highlight uromodulin’s role in modulating local rheology, which may contribute to urine’s colloidal stability and prevention of pathological crystallization. The study bridges structural insights from SAXS with functional assays, offering a mechanistic understanding of uromodulin’s role in urinary physiology.
An analytical review of state-of-the-art approaches to creating high-sensitivity sensors based on the tunnel magnetoresistive (TMR) effect is presented. The progress in magnetic semiconductor technologies and spintronics is described, focusing on the selection and optimization of materials, design and study of various magnetic tunnel junction configurations, and integration of magnetic field concentrators into the TMR sensor architecture. Experimental data from foreign sources regarding the achieved magnetic field detection limits and noise reduction performance in TMR sensors are provided. The application of TMR sensors in biomagnetic measurements, including magnetoencephalography and magnetocardiography, is discussed and results obtained from real-world clinical practice on patients are reported.
The optical properties and stability of CsPbBr3 perovskite quantum dots (PQDs) in water have been investigated using L-glutamic acid, L-aspartic acid, and glutathione as stabilizing ligands in combination with octadecylamine (ODA). Synthesis was carried out via a ligand-assisted reprecipitation method, whereby ODA formed a hydrophobic barrier, protecting the nanoparticles from water exposure, while the amino acids facilitated the formation of a hydrophilic surface on the PQDs. The 17 highest stability and photoluminescence quantum yield (PLQY ≈ 81
Two aspects of a new theory for nanofocusing synchrotron radiation (SR) into nanometer-scale transverse dimensions using a long compound refractive lens (CRL) are considered. First, a method for calculating the rocking curve, which differs from the Gaussian function and depends on the actual aperture size of the CRL, is developed. Second, a new method for calculating the wave function transformation as SR passes through air after focusing in the CRL, including in the region near the focal length, is proposed. The new method is based on an analytical representation of the Huygens–Fresnel integral through a complex Fresnel integral. It yields results in the same time or even faster than the method based on the Fourier transform and is simpler and more stable.
The morphology of native vesicles obtained from 6 previously undescribed in the literature producers belonging to the kingdoms of plants and fungi was studied for the first time using the cryo-electron microscopy method. Based on the obtained microphotographs, a comparative analysis of vesicle morphological characteristics, such as size, multilayeredity and integrity of the double phospholipid layer, was carried out, and the most promising objects for further studies of plant and fungal vesicles as carriers of therapeutic molecules were selected.
Plant-derived exosome-like nanoparticles (ELNPs) are cell-secreted extracellular vesicles (EVs), which contain miRNAs that regulate plant physiology and can be used for intercellular communication. In this study, the Nauclea officinalis-derived ELNPs (N-ELNPs) were isolated via ultracentrifugation and characterized by transmission electron microscopy. Their miRNAs were analyzed through high-throughput sequencing and target gene and function prediction was conducted using miRDeep, miRBase, miRanda, GO, and KEGG. The obtained results showed that N-ELNs (50–200 nm, vesicular) harbored 875 known and 62 novel miRNAs; top 10 expressed miRNAs belonged to MIR172, MIR1919, and MIR396 families. Conducted GO enrichment covered 10 major biological processes, 2 cellular components, and 8 molecular functions; KEGG enrichment involved 10 pathways linked to plant hormonal signal transduction, lipid metabolic reprogramming, branched-chain amino acid catabolism, energy homeostasis, and specialized metabolite production. The obtained data guide future research to identify specific targets for regulation via N-ELNPs and their miRNAs both within the plants themselves and in the potential regulation of gene expression in animal cells.
The results of investigations of functional chromium nitride-based coatings obtained by magnetron sputtering of a hot (uncooled) chromium target at different nitrogen contents are reported. The CrN coatings should provide a low-resistance contact in a densely packed fuel cell stack and corrosion protection of fuel cell stack components based on hydrogen‒air fuel cells with a proton-exchange membrane. It is shown that the use of hot targets, compared with the use of cooled ones, allows an almost two-fold increase in the productivity of the coating application process. This changes the surface morphology and structure of the CrN films and the surface contact resistance at the gas diffusion electrode–bipolar plate interface of the PEM fuel cell decreases to Rs = 1.34 mΩ cm2. As the nitrogen content in the argon plasma increases at the same hot target magnetron sputtering time, the rate of formation of the protective films increases and the surface contact resistance decreases, while their corrosion characteristics deteriorate.
The process of formation of a new type of agglomerates of silver nanoparticles formed during the adsorption of albendazole has been studied. It has been shown that at the isoelectric point (pH 6.3), albendazole molecules, adsorbed on the surface of nanoparticles, induce their agglomeration with the formation of loose structures stabilized mainly by hydrophobic interaction. This process leads to the formation of “hot spots” with a local enhancement of the electromagnetic field, which is confirmed by a sharp increase in the intensity of the giant Raman scattering signal. These agglomerates have fundamental differences in structure and stability from agglomerates induced by electrostatic interaction. They exhibit high intensity giant Raman scattering, unique morphology, and pH-dependent adsorption. A comprehensive study using Raman spectroscopy, dynamic light scattering, ζ-potential measurements, scanning electron microscopy, and high-performance liquid chromatography confirmed the formation of a new type of nanostructures with controlled properties. The obtained results open up prospects for the development of highly efficient substrates for giant Raman scattering and targeted drug delivery systems.
A bioresorbable tubular graft with a diameter less than 5 mm intended for reconstruction of blood vessels was developed; the inner layer of the graft consisted of poly(L-lactide) nanofibers, and the outer layer consisted of poly(ε-caprolactone) nanofibers. The in vivo experiments on reconstruction of the rat abdominal aorta showed that the implants had good biocompatibility and high thromboresistance in the absence of cytotoxicity. The morphological studies revealed two processes occurring simultaneously in the implant: bioresorption of polymeric fibers and formation of blood vessel tissues. It was established that after 24 months of observation, a vessel fragment was formed at the site of the polymeric implant: its neointima consisted of epithelial and subepithelial layers, and neomedia included connective tissue cells and fibers, as well as the remnants of fragmented poly(L-lactide) and poly(ε-caprolactone) nanofibers. The outer layer of the graft (neoadventitia) consisted of a network of collagen fibers, numerous vasa vasorum, isolated multinucleated foreign body giant cells and macrophages.
Biofouling is the process of settlement of living organisms including bacteria on submerged or frequently moistened underwater structures, industrial facilities, and historical and cultural monuments which leads to their damage, changes in chemical and physical characteristics, and deterioration of the appearance. This paper proposes an effective method for protecting structures against biofouling using biocidal silver–selenium-containing nanoparticles (Ag–Se NPs) obtained by bacterial synthesis and introduced as fillers into the composition of industrial polymer paint-and-varnish materials. Polymer nanocomposites obtained based on oil and acrylic paints, yacht and decorative varnishes, enamel, and epoxy glue exhibit a high level of biocidal activity against a number of Gram(+) and Gram(−) bacteria and yeasts. Biogenic nanoparticles obtained by the “green chemistry” method can be used as new-generation antimicrobial agents for protecting various objects against biofouling.
Silver proteinate such as Protargol, first synthesized in 1897, is currently used to treat infectious diseases of human. In Russia, Protargol is produced by a number of commercial companies, using different synthesis technologies and reagents and without disclosing the characteristics and properties of the resulting drug. Thus, commercially available samples of Protargol are not sufficiently characterized for environment. In this work commercial samples of Protargol have been characterized using modern analytical techniques such as electron microscopy, energy-dispersive X-ray microanalysis, X-ray diffractometry, dynamical light scattering, UV spectrophotometry and high-performance liquid chromatography, which allowed to identify their new properties. It has been established that Protargol is essentially a solution of crystalline silver nanoparticles stabilized a protein (in particular, collagen). It has been shown that Protargol can be used as a commercially and financially accessible source of model silver nanoparticles for scientific research, which is very relevant. The range of possible applications of silver proteinate in medicine and agriculture has been expanded.
The prospects of using two-phase heterogeneous hydrogel media for generating nanocrystalline structures (nanoclusters) of silver have been studied. It has been shown that nanoclusters formed in heterogeneous media retain their luminescence properties for a long time. The nanoclusters obtained in this way can be used as an element of an analytical sensor system for rapid assessment of the level of general metabolic activity of living cells. Modeling of processes occurring at the early stages of formation of nanocrystalline structures de novo has been carried out.
Production of highly porous nanomaterials is an emerging trend that involves the conversion of plant-based polymers, agricultural residues, and forest industry byproducts into value-added products. This process is aligned with the goals of environmental sustainability, efficient use of resources and addressing food security issues through the synthesis of chemical and biological substances. In this study, ultralight (0.031–0.086 g/cm3) macroporous materials derived from biomodified pulps with varied compositions, degrees of conversion, and crystallinity are prepared and analyzed by scanning electron microscopy, low-temperature adsorption–desorption of nitrogen, Fourier-transform infrared spectroscopy, etc. It is shown that these highly porous materials exhibit characteristics consistent with those of cryogel scaffolds, featuring interconnected nanostructure, mechanical stability, porosity of 93.8–97.8
Transparent conducting nonstoichiometric indium oxide (In2O3–х) thin films have been obtained by RF magnetron sputtering of a ceramic target in an inert argon atmosphere. It is shown that, during the nonequilibrium deposition, the substrate temperature and atmospheric composition directly affect the nonstoichiometry of the deposited material and the defect structure of its nanocrystalline state. It has been concluded by analyzing the observed dependences that the nonstoichiometric film growth occurs under the condition of competing processes of heterogeneous indium oxidation and thermal desorption of oxygen from the growing surface, which prevail at a certain substrate temperature. The resulting defect structure ultimately determines the characteristics of carrier transport in the In2O3–х thin film and the thermal stability of its electrical properties.
