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The influence of the calcination process on the physicochemical properties and catalytic behavior of the Co/Mg/La catalysts for ammonia synthesis has been investigated. The catalysts were prepared using the different thermal pre-treatment methods prior to the activation, i.e., drying and calcination, and the respective activities for ammonia synthesis were assessed. It was found out that changing from air calcination prior to activation to direct activation of the co-precipitated species led to the different catalytic performances. The most favorable catalytic performance was achieved with Co/Mg/La prepared by calcination in air. Detailed characterization methods, employing e.g., XRPD, H2-TPD, N2-TPD, CO2-TPD, SEM, and TEM, showed that the superior catalytic behavior of this catalyst was attributed to its strong basicity and favorable adsorption properties toward hydrogen and nitrogen.

The replacement of affected blood vessels of the polymer material can cause imbalances in the blood haemostatic system. Changes in blood after the implantation of vascular grafts depend not only on the chemical composition but also on the degree of surface wettability. The Dallon® H unsealed hydrophilic knitted vascular prosthesis double velour was assessed at work and compare with hydrophobic vascular prosthesis Dallon®. Spectrophotometric studies were performed in the infrared and differential scanning calorimetry, which confirmed the effectiveness of the process of modifying vascular prostheses. Determination of the parameters of coagulation time of blood after contact in vitro with Dallon® H vascular prosthesis was also carried out. Prolongation of activated thromboplastin time, decreased activity of factor XII, IX and VIII, were observed. The prolonged thrombin and fibrinogen were reduced in the initial period of the experiment. The activity of plasminogen and antithrombin III and protein C were at the level of control value. The observed changes in the values of determined parameters blood coagulation do not exceed the range of referential values for those indexes. The observed changes are the result of considerable blood absorptiveness by the prosthesis of blood vessels and their sealing.

Reversible oxidation-reduction of cerium ions in a monoclinic Ce4Al2O9 aluminate was studied by XRD, TEM, temperature programmed reduction-oxidation and magnetic methods. It has been shown that nanocrystalline Ce4Al2O9 reacts with gaseous oxygen, undergoing at 20–300 °C transformation into a new, oxidized phase described in the same P21/c space group, but with 10% smaller unit cell volume. Magnetic measurements revealed that the oxidized Ce4Al2O9 still contains ~20% of paramagnetic Ce3+ ions. The oxidized Ce aluminate may be reduced back to Ce4Al2O9 by heating in H2 atmosphere to 1000 °C. The reversibility of the oxidation-reduction process of Ce4Al2O9 aluminate bears resemblance to the behaviour of fluorite type CeO2, and may be of interest for applications (e.g., in catalytic high-temperature oxidation reactions).

Analysis of bipolar thermal conductivity might be very useful in preliminary stages of thermoelectric materials discovery. Using its product---mobility ratio between electrons and holes---it is possible to choose the most promising compound from the series and pave the correct direction of doping. Current work presents positive verification of this approach for $\mathrm{Sc}\mathrm{Ni}\mathrm{Sb}$, which is anticipated to show superior mobility when tuned towards n-type behavior. In agreement with expectation, the mobility increases by an order of magnitude due to rising tellurium content in the ${\mathrm{Sc}\mathrm{Ni}\mathrm{Sb}}_{1\ensuremath{-}x}{\mathrm{Te}}_{x}$ series. The effect is most likely driven by change of the dominant charge carriers' scattering mechanism from ionized impurity influence to point defect and acoustic phonon interaction. Simultaneously, due to a highly anisotropic conduction band, the effective mass of the carriers rises towards the n-type regime. These two effects lead to an improved thermoelectric power factor of electron-doped samples, up to $40\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}{\mathrm{WK}}^{\ensuremath{-}2}\phantom{\rule{0.2em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ at 740 K for ${\mathrm{Sc}\mathrm{Ni}\mathrm{Sb}}_{0.85}{\mathrm{Te}}_{0.15}$. Based on this result, we suggest n-type doping for other rare-earth-based half-Heusler compounds. Representatives of this group exhibit the smallest lattice thermal conductivity in the pristine form among any half-Heusler thermoelectrics, and are anticipated to show comparably good electrical properties to ScNiSb due to their high mobility ratio in favor of electrons.

The oxidation of soot over RuRe bimetallic nanoparticles (NPs) supported on γ-Al2O3 has been investigated. The catalysts were synthesized by a microwave-polyol method and characterized by ICP, BET, TEM, STEM-EDS, XRD and XPS techniques. The study revealed that the proper choice of the Re loading (0.4–2.0 wt%) is crucial for the catalytic behavior of the 2% Ru–Re/Al2O3 nano-catalysts.The best catalytic properties, in terms of overall activity and stability, were observed for the 2%Ru-0.8%Re/γ-Al2O3 nano-catalyst. The stability of all bimetallic 2% Ru–Re nano-catalysts in catalytic soot oxidation in the presence of oxygen is very high in contrast to the 2% Ru/γ-Al2O3 sample. The presence of rhenium in the catalytic system hinder the formation of large RuO2 agglomerates leading to a better dispersion of active ruthenium phase and a better catalytic performance. The relationship between the catalytic activity of Ru–Re/γ-Al2O3 and the synergetic roles of Ru and Re is discussed.

Looking for upconverting biocompatible nanoparticles, we have prepared by the sol–gel method, silica–calcia glass nanopowders doped with different concentration of Tm3+ and Yb3+ ions (Tm3+ from 0.15 mol% up to 0.5 mol% and Yb3+ from 1 mol% up to 4 mol%) and characterized their structure, morphology, and optical properties. X-ray diffraction patterns indicated an amorphous phase of the silica-based glass with partial crystallization of samples with a higher content of lanthanides ions. Transmission electron microscopy images showed that the average size of particles decreased with increasing lanthanides content. The upconversion (UC) emission spectra and fluorescence lifetimes were registered under near infrared excitation (980 nm) at room temperature to study the energy transfer between Yb3+ and Tm3+ at various active ions concentrations. Characteristic emission bands of Tm3+ ions in the range of 350 nm to 850 nm were observed. To understand the mechanism of Yb3+–Tm3+ UC energy transfer in the SiO2–CaO powders, the kinetics of luminescence decays were studied.

Ni-rich layered oxides, i.e., LiNi0.6Mn0.2Co0.2O2 (NMC622) and LiNiO2 (LNO), were prepared using the two-step calcination procedure. The samples obtained at different calcination temperatures (750&ndash, 950 &deg, C for the NMC622 and 650&ndash, 850 &deg, C for the LNO cathode materials) were characterized using nitrogen physisorption, PXRD, SEM and DLS methods. The correlation of the calcination temperature, structural properties and electrochemical performance of the studied Ni-rich layered cathode materials was thoroughly investigated and discussed. It was determined that the optimal calcination temperature is dependent on the chemical composition of the cathode materials. With increasing nickel content, the optimal calcination temperature shifts towards lower temperatures. The NMC-900 calcined at 900 &deg, C and the LNO-700 calcined at 700 &deg, C showed the most favorable electrochemical performances. Despite their well-ordered structure, the materials calcined at higher temperatures were characterized by a stronger sintering effect, adverse particle growth, and higher Ni2+/Li+ cation mixing, thus deteriorating their electrochemical properties. The importance of a careful selection of the heat treatment (calcination) temperature for each individual cathode material was emphasized.

In the present study, a nanoapatite-mediated delivery system for imatinib has been proposed. Nanohydroxyapatite (nHAp) was obtained by co-precipitation method, and its physicochemical properties in combination with imatinib (IM) were studied by means of XRPD (X-ray Powder Diffraction), SEM-EDS (Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy), FT-IR (Fourier-Transform Infrared Spectroscopy), absorption spectroscopy as well as DLS (Dynamic Light Scattering) techniques. The obtained hydroxyapatite was defined as nanosized rod-shaped particles with high crystallinity. The amorphous imatinib was obtained by conversion of its crystalline form. The beneficial effects of amorphous pharmaceutical agents have been manifested in the higher dissolution rate in body fluids improving their bioavailability. Imatinib-to-hydroxyapatite interactions on the surface were confirmed by SEM images as well as absorption and FT-IR spectroscopy. The cytotoxicity of the system was tested on NI-1, L929, and D17 cell lines. The effectiveness of imatinib was not affected by nHAp modification. The calculated IC50 values for drug-modified nHAp were similar to those for the drug itself. However, higher cytotoxicity was observed at higher concentrations of imatinib, in comparison with the drug alone.

Amyloid fibrils are widely studied both as target in conformational disorders and as basis for the development of protein-based functional materials. The three Zr phthalocyanines bearing dehydroacetic acid residue (PcZr(L1)2) and its condensed derivatives (PcZr(L2)2 and PcZr(L3)2) as out-of-plane ligands were synthesized and their influence on insulin fibril formation was studied by amyloid-sensitive fluorescent dye based assay, scanning electron microscopy, fluorescent and absorption spectroscopies. The presence of Zr phthalocyanines was shown to modify the fibril formation. The morphology of fibrils formed in the presence of the Zr phthalocyanines differs from that of free insulin and depends on the structure of out-of-plane ligands. It is shown that free insulin mostly forms fibril clusters with the length of about 0.3–2.1 μm. The presence of Zr phthalocyanines leads to the formation of individual 0.4–2.8 μm-long fibrils with a reduced tendency to lateral aggregation and cluster formation (PcZr(L1)2), shorter 0.2–1.5 μm-long fibrils with the tendency to lateral aggregation without clusters (PcZr(L2)2), and fibril-like 0.2–1.0 μm-long structures (PcZr(L3)2). The strongest influence on fibrils morphology made by PcZr(L3)2 could be explained by the additional stacking of phenyl moiety of the ligand with aromatic amino acids in protein. The evidences of binding of studied Zr phthalocyanines to mature fibrils were shown by absorption spectroscopy (for PcZr(L1)2 and PcZr(L2)2) and fluorescent spectroscopy (for PcZr(L3)2). These complexes could be potentially used as external tools allowing the development of functional materials on protein fibrils basis.

The effects of heat treatment temperature, time and isostatic pressure on the grain connectivity and superconducting properties of Mg11B2 wires prepared using nano-amorphous isotopic boron powder (11B) have been investigated. The article presents detailed studies of the Mg11B2 material structure of the wires using scanning electron microscope (SEM). Heat treatment at low and high temperature for different annealing time and isostatic pressure does not create an internal macro-defect that disrupts connectivity in the Mg11B2 superconducting wires. Our study shows that dense longitudinal superconducting layers are formed at high annealing temperature of 800 °C for 60 min. Formation of dense longitudinal superconducting layers under high isostatic pressure (HIP) allow improved grain connectivity and high density of pinning centers and as a result, high engineering critical current density, Jec, at 4.2 K has been achieved. Also, high upper critical field (Bc2) and high irreversible magnetic field (Birr) were obtained using HIP process while superconducting transition temperature (Tc) was not significantly affected. Better grain connectivity obtained using high annealing temperature and long annealing time under low isotopic pressure leads to Jec enhancement at high magnetic fields at 20 K. Our results show that the annealing temperature of 800 °C for 60 min under isostatic pressure of 1 GPa yields the required Jec of 25 A/mm2 and 50 A/mm2 for ITER applications in magnetic fields of 8 T and 7 T, respectively. The promising results obtained in this work could pave the way for designing low activation superconducting Mg11B2 wires to be considered for next generation fusion magnets.

In this paper, the optical properties of Y 2 Te 4 O 11 microcrystalline powders doped with Dy 3+ ions, ranging between 0.01 and 5.0 at%, are reported. The powders were successfully synthesized by the solid state reaction method. Absorption (300 K), excitation (300 K) and fluorescence spectra (at 11.6 and 300 K) as well as fluorescence decay curves recorded at room temperature are presented and analyzed in details. Oscillator strengths, phenomenological Ω λ ( λ =2, 4, 6) Judd-Ofelt parameters, radiative transition probabilities, branching ratios, the radiative lifetime of the 4 F 9/2 level as well as the stimulated emission cross-section for the 4 F 9/2 → 6 H 13/2 transition have been determined. The observed non-exponential decay nature and concentration quenching of the 4 F 9/2 emitting level of the Dy 3+ ion, have been attributed to cross-relaxation processes. The high value of the stimulated emission cross-section for the 4 F 9/2 → 6 H 13/2 transition at 576.6 nm, equal to 0.756×10 −20 cm 2 , indicates that Y 2 Te 4 O 11 activated by trivalent dysprosium ions is an attractive candidate for a solid-sate laser.

Among a wide variety of solid state materials, alkali lanthanide double phosphates are the subject of extensive spectroscopic investigations for their application as laser active materials. The edge of absorption in this compound is at rather high energies, which makes them suitable as efficient host for luminescent materials. Spectroscopic properties of Sm3+-doped K3Y(PO4)2 are reported basing on the high resolution absorption and emission spectra for various temperatures mainly at 4, 10, and 293 K from UV to IR range. The effects of concentration and temperature on intensities and shape of the observed bands were studied. Radiative transition probabilities were calculated from absorption spectra and Judd–Ofelt parameters evaluated. The excited state dynamics will be discussed based on the decay time measurement.

Spectroscopic properties of Sm3+-doped Y2Te4O11 micro-crystals were studied in the 6000–18,500 cm−1 spectral range. Vibrational, electronic absorption, fluorescence and excitation spectra as well as fluorescence dynamics of the Sm3+-doped title micro-crystals are presented and analyzed in detail. A Judd–Ofelt intensity analysis of the absorption spectrum at 300 K has been applied for determination of Ωλ parameters which in turn have been used for calculations of the radiative transition probability factor (A), the fluorescence branching ratios (β), the natural (radiative) lifetime of the 4G(4)5/2 level of Sm3+ and the emission cross-section (σem). An analysis of the non-radiative decay was based on the cross-relaxation mechanisms. The achieved results indicate that the investigated samples are potentially applicable as a 605 and 652 nm laser host as well as an orange phosphor.

Single crystals of α-Sm3+:Na3Y(VO4)2 have been grown by the flux growth method. The absorption (300 K) fluorescence (4.2 and 300 K) and excitation (7 and 300 K) spectra as well as the fluorescence dynamics of the Sm3+-doped title crystals are presented and analyzed in detail. The energy transfer between Sm3+–Sm3+ as well as from VO43− to Sm3+ were studied in detail. A Judd–Ofelt intensity analysis of the absorption (300 K) spectrum has been applied for determination of Ωλ parameters which in turn have been used in calculation of the radiative transition probability factor (A), fluorescence branching ratios (β), natural (radiative) lifetime of the 4G(4)5/2 level of Sm3+ and emission cross-section (σem). For the first time very large lifetimes of the Sm3+ fluorescence level have been observed.