Deformation and Fracture of Corundum Ceramics with a Multilevel Pore Structure

Technical Physics - The behavior of Al2O3 ceramics having a 50% volume of pore space under compression is studied. The porous structure includes three types of pores: large porosity with an average...     

Determination of acamprosate in human plasma by UPLC–MS/MS: Application to therapeutic drug monitoring

Acamprosate is a medication used to treat alcohol dependence. Therapeutic drug monitoring is important in drugs for the treatment of substance-related disorders. Therefore, in this study, a new selective, very simple and rapid ultra-performance liquid chromatography–tandem mass spectrometer method was developed for the therapeutic drug monitoring of acamprosate. The developed method allows the determination of acamprosate in human plasma. The method was validated in terms of selectivity and linearity, which was in the range of 100–1,200 ng/ml for acamprosate. Intra-assay and inter-assay accuracy and precision were within the acceptable limits of the Eueopean Medicines Agency guideline. The lower limit of quantitation was 100 ng/ml for acamprosate. The developed method was successfully applied for therapeutic drug monitoring in patient plasma samples.     

New Ga-enriched reconstructions on the GaAs(001) surface

To prepare structure-ordered GaAs(001) surfaces at low temperatures, GaAs(001) surfaces coated with native oxides were exposed in an atomic hydrogen flow in the temperature range 280–450 °C. The new Ga-enriched GaAs(001) surfaces with the (4 × 4) and (2 × 4)/c(2 × 8) reconstructions were prepared and studied by the methods of X-ray photoelectron spectroscopy, low-energy electron diffraction, and high-resolution characteristic electron energy loss spectroscopy. For the GaAs(001)-(2 × 4) surface, the structure of the Ga-stabilized surface has been proposed and ab initio computed within the (2 × 4) Ga-trimer unit cell model.     

Emergence of convective flows during diffusional mass transfer in ternary gas systems: The effect of component concentrations

Specific features of diffusional mass transfer in ternary gas mixtures and their relation to the concentration of the densest component in a mixture are studied experimentally under isothermic conditions. At certain compositions of the gas mixture, unique diffusion regimes develop in the system that are characterized by a considerable rate of mass transfer and are attributed to the presence of concentration convection. We show that transitions from the diffusional and convective regimes can be predicted using the stability theory extended to isothermal mixing in ternary gas systems. Theoretical predictions are compared to experimental data.     

α-In2S3 and β-In2S3 phases produced by SILAR technique

In₂S₃ films have been deposited by the successive ionic adsorption and reaction technique (SILAR) at room temperature. The films have been examined to evaluate the structural and optical properties. X-ray diffraction spectra have revealed the presence of both the α-In₂S₃ (cubic) and β-In₂S₃ (tetragonal) phases. The presence of the α-In₂S₃ phase at room temperature is attributed to the richness of In in the deposited materials. The presence of both phases is also supported by FESEM observations. The crystallinity of the material has been observed to improve with increasing thickness. Direct band gap of the deposits decreased from 2.89 to 2.37?eV with increasing thickness.     

Theoretical study of adhesion at the metal-zirconium dioxide interfaces

The atomic and electronic structure of the interfaces between metals with body-centered cubic (bcc) and face-centered cubic (fcc) structures and zirconium dioxide is studied systematically using the ab initio methods of the electron density functional theory (DFT). It is shown that high adhesion properties can be attained at the nonstoichiometric polar Me(001)/ZrO₂(001) interface with bcc metals from the middle of the 4d–5d periods (Mo, Ta, W, and Nb). Charge transfer from the metal to the oxide substrate ensures the strong ionic chemical bond on the metal-ceramic interfaces. The structural and electronic factors responsible for lowering of adhesion at differently oriented interfaces are analyzed. It is shown that a decrease of adhesion at the (110) nonpolar stoichiometric interface is due to an increase in the interfacial spacing as well as a decrease in the number of metal-oxygen bonds. The effect of doping with oxides (CaO, MgO, and Y₂O₃) stabilizing zirconium dioxide at low temperatures on the adhesion energy at the Me(001)/ZrO₂(001) interface is analyzed.     

Gas chromatographic properties of methacrylate polymers modified by silver nanoparticles

Russian Chemical Bulletin - The gas chromatographic properties of the porous methacrylate polymers, copolymers of 2,3-epoxypropyl methacrylate (2,3-EPMA) and ethylenedimethacrylate (EDMA), modified...     

Synthesis,structure, and properties of silver nanocomposite materials with poly(hydroxyethyl methacrylate) matrix

The mechanism of photoreduction of silver particles from colloidal solutions in 2-hydroxyethyl methacrylate, followed by its photopolymerization for preparing antirefl ection coatings, is considered.     

Sulfonated N‐heterocyclic carbine‐silver (I) complexes: Synthesis,characterisation and biological evaluation

The synthesis, characterisation and biological activity of water‐soluble Ag(I)‐NHC complexes, general formula Na[(NHC)AgCl] where NHC is a sulfonated and sterically hindered N‐heterocyclic carbene, is reported. The Ag‐NHC complexes (2a–e) were synthesised by reacting the corresponding sulfonated NHC ligands with Ag₂O in the presence of NaCl or NaBr in methanol/water (1:1) solution. Synthesised silver (I)‐N‐heterocyclic carbene complexes have been characterised by NMR, micro‐analysis and HRMS spectroscopic methods. The IC₅₀ values of these complexes were determined by a proliferation BrdU enzyme‐linked immunosorbent assay (ELISA) against HeLa (human cervix carcinoma), HT29 (human adenocarcinoma) and L929 (mouse fibroblast) cell lines. These complexes have been highlighted as promising and original platforms for building new types of metalodrug. All new water‐soluble Ag(I) complexes demonstrated remarkable cytotoxic activity against HeLa, HT29 and L929 cell lines.     

Study of the interaction of mono-, di-, and trisubstituted sodium orthophosphates with thermally activated dolomite

Interaction of dolomite thermally treated at 800°C with solutions of mono-, di-, and trisubstituted sodium phosphate was studied. It was shown that thermally treated dolomite binds 0.75 to 3.0 mmol g^–1 of phosphorus, depending on the nature of a phosphating reagent, and the interaction mostly occurs with magnesium oxide, which enables use of this kind of dolomite as a sorbent of phosphate ions. It was found that the nature of the phosphating reagent affects the chemical and phase composition of the materials obtained, as well as their sorption properties with respect to heavy metal ions. The products formed in acid-free phosphation of dolomite have high sorption capacity, from 1.5 to 6.8 mmol g^–1 for Pb²⁺, Zn²⁺, Cu²⁺, Cd²⁺, Ni²⁺, Sr²⁺, and Co²⁺ ions, which enables their use as effective sorbents for heavy metal ions.urning.