Unique Self-Phosphorylating Polybenzimidazole of the 6F Family for HT-PEM Fuel Cell Application.

High-temperature polymer-electrolyte membrane fuel cells (HT-PEMFCs) are a very important type of fuel cells since they operate at 150-200 °C, making it possible to use hydrogen contaminated with CO. However, the need to improve the stability and other properties of gas-diffusion electrodes still impedes their distribution. Self-supporting anodes based on carbon nanofibers (CNF) are prepared using the electrospinning method from a polyacrylonitrile solution containing zirconium salt, followed by pyrolysis.

Development of an innovative diffraction scattering theory of X-rays and electrons in imperfect crystals.

Fundamental equations describing the X-ray and electron diffraction scattering in imperfect crystals have been derived in the form of the matrix Fredholm-Volterra integral equation of the second kind. A theoretical approach has been developed using the perfect-crystal Green function formalism. In contrast, another approach utilizes the wavefield eigenfunctions related to the diagonalized matrix propagators of the conventional Takagi-Taupin and Howie-Whelan equations.

Features of the crystal structure and surface of superprotonic conductor caesium hydrogen sulfate phosphate.

The crystal structure of superprotonic conductor caesium hydrogen sulfate phosphate [Cs(HSO)(HPO)] have been analyzed using neutron diffraction methods. Additionally, its structure and surface layers have been investigated using atomic force microscopy. From the diffraction data obtained, Fourier syntheses of neutron scattering densities were calculated, and the localization of hydrogen atoms and the parameters of three types of hydrogen bonds in the crystal structure were accurately determined.

Extensive research of conductivity in the fluorite-like KLnMoOF (Ln = La, Pr, Nd) rare earth molybdates: theoretical and experimental data.

The conductive properties of fluorite-like structures KLnMoOF (Ln = La, Pr, Nd: KLM, KPM, KNM) have been studied theoretically and experimentally. Theoretical studies included the geometrical-topological analysis of voids and channels available for migration of working ions; bond valence site energy calculations of the oxygen ions' migration energy; quantum-chemical calculations for the estimation of the oxygen vacancies formation energy. Experimental measurements of conductivity were made using impedance spectroscopy and as a function of oxygen partial pressure.

Effect of ligand and shell densities on the surface structure of core-shell nanoparticles self-assembled from function-spacer-lipid constructs.

Biomolecular corona is the major obstacle to the clinical translation of nanomedicines. Since corona formation is governed by molecular interactions at the nano-bio interface, nanoparticle surface properties such as topography, charge and surface chemistry can be tuned to manipulate biomolecular corona formation. To this end, as the first step towards a deep understanding of the processes of corona formation, it is necessary to develop nanoparticles employing various biocompatible materials and characterize their surface structure and dynamics at the molecular level.

Selection of Aptamers for Use as Molecular Probes in AFM Detection of Proteins.

Currently, there is great interest in the development of highly sensitive bioanalytical systems for diagnosing diseases at an early stage, when pathological biomarkers are present in biological fluids at low concentrations and there are no clinical manifestations. A promising direction is the use of molecular detectors-highly sensitive devices that detect signals from single biomacromolecules. A typical detector in this class is the atomic force microscope (AFM).

Lanthanide Contraction in F ( = Ce-Lu) and Its Chemical and Structural Consequences: Part 2: Specialized Empirical System of ( = Y, La, and 14 ) and F Ionic Radii for F Series.

A () () for = Y, La, , and F ( rare earth elements ()) was derived from the dependence of () on the () of (). LC decreased the radius of the cation with increasing Z. The structures of -F (LaF-NdF, "-SmF") of the LaF type, 11 -F ( = Sm-Lu), and -YF of the β-YF type were studied.

Lanthanide Contraction in F ( = Ce-Lu) and Its Chemical and Structural Consequences: Part 1: Location of YF in the F Series According to Its Chemical and Structural Characteristics.

A of 14 () from Ce to Lu consists of the interaction of nucleus with -electrons. (REEs-) include Sc, Y, La, and 14 . They are located in 4-6th periods of the subgroup of group III.

A Direct Comparison of Peptide Drug Delivery Systems Based on the Use of Hybrid Calcium Phosphate/Chitosan Nanoparticles versus Unmixed Calcium Phosphate or Chitosan Nanoparticles In Vitro and In Vivo.

Nanocarriers provide a number of undeniable advantages that could improve the bioavailability of active agents for human, animal, and plant cells. In this study, we compared hybrid nanoparticles (HNPs) consisting of a calcium phosphate core coated with chitosan with unmixed calcium phosphate (CaP) and chitosan nanoparticles (CSNPs) as carriers of a model substrate, enalaprilat. This tripeptide analog is an inhibitor of angiotensin-converting enzyme and was chosen by its ability to lower intraocular pressure (IOP).

Thermodynamic Origin of Negative Thermal Expansion Based on a Phase Transition-Type Mechanism in the GdF-TbF System.

Multicomponent fluorides of (s-) are () materials. NTE-II occurs in F-F systems formed by "mother" single-component dimorphic F ( = Pm, Sm, Eu, and Gd) with a giant NTE-II. There are two structural types of F polymorphic modifications: low-temperature β-YF (-) and high-temperature LaF (-).

Unlocking the out-of-plane dimension for photonic bound states in the continuum to achieve maximum optical chirality.

The realization of lossless metasurfaces with true chirality crucially requires the fabrication of three-dimensional structures, constraining experimental feasibility and hampering practical implementations. Even though the three-dimensional assembly of metallic nanostructures has been demonstrated previously, the resulting plasmonic resonances suffer from high intrinsic and radiative losses. The concept of photonic bound states in the continuum (BICs) is instrumental for tailoring radiative losses in diverse geometries, especially when implemented using lossless dielectrics, but applications have so far been limited to planar structures.

Isolation of cubic SiP in the form of nanocrystals.

This article describes an approach for synthesizing silicon phosphide nanoparticles with a defective zinc blende structure under mild conditions through thermal annealing of hydrogenated silicon nanoparticles with red phosphorus. The synthesized SiP nanoparticles were analyzed using FTIR, XRD, electron diffraction, EDX, TEM, Raman spectroscopy, X-ray fluorescence spectrometry, and UV-vis spectrophotometry. For the isolated cubic SiP phase, a cell parameter of = 5.

Association of 2-oxoacid dehydrogenase complexes with respirasomes in mitochondria.

In the present study, cryo-electron tomography was used to investigate the localization of 2-oxoacid dehydrogenase complexes (OADCs) in cardiac mitochondria and mitochondrial inner membrane samples. Two classes of ordered OADC inner cores with different symmetries were distinguished and their quaternary structures modeled. One class corresponds to pyruvate dehydrogenase complexes and the other to dehydrogenase complexes of α-ketoglutarate and branched-chain α-ketoacids.

Hexakis-2-(β-carboxyethenylphenoxy)cyclotriphosphazene: Synthesis, Properties, Modeling Structure.

Condensation of hexakis-2-(formylphenoxy)cyclotriphosphazene with malonic acid yielded hexakis-2-(β-carboxyethenylphenoxy)cyclotriphosphazene (2-CEPP), whose structure was confirmed by P, H, C NMR spectroscopy and MALDI-TOF mass spectrometry. A quantum-chemical calculation for the 2-CEPP molecule using the ab initio methods in the 6-311G basis set and the DFT-PBE0/6-311g** method was performed with geometry optimization of all parameters by the standard gradient method. The acid strength of 2-CEPP was theoretically estimated.

The Synthesis, Structure, and Luminescent Properties of TmMgBO Crystals.

TmMgBO spontaneous crystals were synthesized via the flux-growth technique from a KMoO-based solvent. The crystal structure of the compound was solved and refined within the space group 2/. The first principles calculations of the electronic structure reveal that TmMg-pentaborate with an ideal not defected crystal structure is an insulator with an indirect energy band gap of approximately 6.

Two-Component Rare-Earth Fluoride Materials with Negative Thermal Expansion Based on a Phase Transition-Type Mechanism in 50 F-'F ( = La-Lu) Systems.

The formation of materials with () based on a () in 50 (temperature-composition) F-'F ( = La-Lu) systems out of 105 possible is predicted. The components of these systems are "" F compounds ( = Pm, Sm, Eu, and Gd) with (), which occur during heating between the main structural types of F: -(β-YF) → -( LaF). The PolTr is characterized by a : the (V) of the low-temperature modification (V) is higher than that of the high-temperature modification (V) by a value (up to 4.

doping of epitaxial diamond with germanium by microwave plasma CVD in GeH-CH-H mixtures with optical emission spectroscopy monitoring.

We report the growth of Ge-doped homoepitaxial diamond films by microwave plasma CVD in GeH-CH-H gas mixtures at moderate pressures (70-100 Torr). Optical emission spectroscopy was used to monitor Ge, H, and C species in the plasma at different process parameters, and trends for intensities of those radicals, gas temperature, and excitation temperature, with variations of GeH or CH precursor concentrations, were investigated. The film deposited on (111)-oriented single crystal diamond substrates in a high growth rate regime revealed a strong emission of a germanium-vacancy (GeV) color center with a zero-phonon line at ≈604 nm wavelength in photoluminescence (PL) spectra, confirming the successful doping.

The size effect of BiFeO nanocrystals on the spatial spin modulated structure.

The spatial spin modulated structure (SSMS) of the cycloid type present in bulk BiFeO prevents the linear magnetoelectric effect. One way to influence this structure is to reduce the crystal size to the nanoscale. Various opinions are circulating in the literature about the effect of nanocrystal size on SSMS, and to investigate this issue, we used a number of methods, with zero-field NMR (ZF NMR) spectroscopy at the forefront.

Transformation of Specific Dispersion Interactions between Cellulose and Polyacrylonitrile in Solutions into Covalent Interactions in Fibers.

Morphological transformations in emulsions of cellulose and polyacrylonitrile (PAN) ternary copolymers containing acrylonitrile, methyl acrylate, and methylsulfonate comonomers in -methylmorpholine--oxide were studied over the entire range of concentrations depending on temperature and intensity of the deformation action. Based on the morphological and rheological features of the system, the temperature-concentration range of spinnability of mixed solutions was determined, and composite fibers were spun. The fibers are characterized by a heterogeneous fibrillar texture.

A Porous Nanostructured ZnO Layer for Ultraviolet Sensing with Quartz Crystal Microbalance Technique.

Porous films of metals and metal oxides have gained growing attention as potential materials for use in applications that require large, specific surface areas, such as sensors, supercapacitors, and batteries. In this study, a "black-metal"-like porous Zn-ZnO composite layer was grown by room temperature co-sputtering of Zn metal and ZnO:Ga (3 at/%) ceramic targets. Following deposition, a porous ZnO layer was obtained by a subsequent thermal annealing process at 400 °C in air.

Non-Fermi-Liquid Behavior of Superconducting SnH.

The chemical interaction of Sn with H by X-ray diffraction methods at pressures of 180-210 GPa is studied. A previously unknown tetrahydride SnH with a cubic structure (fcc) exhibiting superconducting properties below T  = 72 K is obtained; the formation of a high molecular C2/m-SnH superhydride and several lower hydrides, fcc SnH , and C2-Sn H , is also detected. The temperature dependence of critical current density J (T) in SnH yields the superconducting gap 2Δ(0) = 21.

Impact of Ge Doping on Structural and Magnetic Ordering in RMnGa and RMnGaGe (R = Tb, Dy; ≤ 0.25, ≈ 1.0-3.3).

Single crystals of RMnGa and their new quaternary derivatives RMnGaGe (R = Tb, Dy, ≤ 0.25, ≈ 1.0-3.

Vortex Phase Dynamics in Yttrium Superhydride YH at Megabar Pressures.

A comprehensive study of vortex phases and vortex dynamics is presented for a recently discovered high-temperature superconductor YH with (onset) of 215 K under a pressure of 200 GPa. The thermal activation energy () is derived within the framework of the thermally activated flux flow (TAFF) theory. The activation energy yields a power law dependence ∝ on magnetic field with a possible crossover at a field around 8-10 T.

Chiral electroluminescence from thin-film perovskite metacavities.

Chiral light sources realized in ultracompact device platforms are highly desirable for various applications. Among active media used for thin-film emission devices, lead-halide perovskites have been extensively studied for photoluminescence due to their exceptional properties. However, up to date, there have been no demonstrations of chiral electroluminescence with a substantial degree of circular polarization (DCP) based on perovskite materials, being critical for the development of practical devices.

S-nitrosylation and S-glutathionylation of GAPDH: Similarities, differences, and relationships.

The aim of this work was to compare the effect of reversible post-translational modifications, S-nitrosylation and S-glutathionylation, on the properties of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and to reveal the mechanism of the relationship between these modifications. Comparison of S-nitrosylated and S-glutathionylated GAPDH showed that both modifications inactivate the enzyme and change its spatial structure, decreasing the thermal stability of the protein and increasing its sensitivity to trypsin cleavage. Both modifications are reversible in the presence of dithiothreitol, however, in the presence of reduced glutathione and glutaredoxin 1, the reactivation of S-glutathionylated GAPDH is much slower (10% in 2 h) compared to S-nitrosylated GAPDH (60% in 10 min).