84 research outputs found

    Magnetic properties of Ruddlesden-Popper phases Sr3x_{3-x}Yx_{x}(Fe1.25_{1.25}Ni0.75_{0.75})O7δ_{7-\delta}: A combined experimental and theoretical investigation

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    We present a comprehensive study of the magnetic properties of Sr3x_{3-x}Yx_{x}(Fe1.25_{1.25}Ni0.75_{0.75})O7δ_{7-\delta} (0x0.750 \leq x \leq 0.75). Experimentally, the magnetic properties are investigated using superconducting quantum interference device (SQUID) magnetometry and neutron powder diffraction (NPD). This is complemented by the theoretical study based on density functional theory as well as the Heisenberg exchange parameters. Experimental results show an increase in the N\'eel temperature (TNT_N) with the increase of Y concentrations and O occupancy. The NPD data reveals all samples are antiferromagnetically ordered at low temperatures, which has been confirmed by our theoretical simulations for the selected samples. Our first-principles calculations suggest that the 3D magnetic order is stabilized due to finite inter-layer exchange couplings. The latter give rise to a finite inter-layer spin correlations which disappear above the TNT_N

    Influence of the presence of different alkali cations and the amount of Fe(CN)6 vacancies on CO2 adsorption on copper hexacyanoferrates

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    The CO2 adsorption on various Prussian blue analogue hexacyanoferrates was evaluated by thermogravimetric analysis. Compositions of prepared phases were verified by energydispersive X-ray spectroscopy, infra-red spectroscopy and powder X-ray diffraction. The influence of different alkali cations in the cubic Fm3m structures was investigated for nominal compositions A2/3Cu[Fe(CN)6]2/3 with A = vacant, Li, Na, K, Rb, Cs. The Rb and Cs compounds show the highest CO2 adsorption per unit cell, ~3.3 molecules of CO2 at 20 \ub0C and 1 bar, while in terms of mmol/g the Na compound exhibits the highest adsorption capability, ~3.8 mmol/g at 20 \ub0C and 1 bar. The fastest adsorption/desorption is exhibited by the A-cation free compound and the Li compound. The influence of the amount of Fe(CN)6 vacancies were assessed by determining the CO2 adsorption capabilities of Cu[Fe(CN)6]1/2 (Fm3m symmetry, nominally 50% vacancies), KCu[Fe(CN)6]3/4 (Fm3m symmetry, nominally 25% vacancies), and CsCu[Fe(CN)6] (I-4m2 symmetry, nominally 0% vacancies). Higher adsorption was, as expected, shown on compounds with higher vacancy concentrations

    Large easy-axis anisotropy in the one-dimensional magnet BaMo(PO4)(2)

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    We present an extensive experimental and theoretical study on the low-temperature magnetic properties of the monoclinic anhydrous alum compound BaMo(PO4)(2). The magnetic susceptibility reveals strong antiferromagnetic interactions theta(CW) = -167 K and long-range magnetic order at T-N = 22 K, in agreement with a recent report. Powder neutron diffraction furthermore shows that the order is collinear, with the moments near the ac plane. Neutron spectroscopy reveals a large excitation gap Delta = 15 meV in the low-temperature ordered phase, suggesting a much larger easy-axis spin anisotropy than anticipated. However, the large anisotropy justifies the relatively high ordered moment, Neel temperature, and collinear order observed experimentally and is furthermore reproduced in a first-principles calculations by using a new computational scheme. We therefore propose BaMo(PO4)(2) to host S = 1 antiferromagnetic chains with large easy-axis anisotropy, which has been theoretically predicted to realize novel excitation continua

    Efficacy and Safety of Flexible Versus Fixed Dosing Intervals of Insulin Glargine 300 U/mL in People with Type 2 Diabetes

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    Background: Insulin glargine 300 U/mL (Gla-300) has a more constant and prolonged action profile than insulin glargine 100 U/mL and in clinical studies is associated with similar glycemic control but less hypoglycemia. Whether its effects are altered by variability of injection time was examined in two 3-month substudies. Materials and Methods: Eligible participants completing 6 months of optimized treatment with Gla-300 in EDITION 1 (n = 109) and EDITION 2 (n = 89), having a mean hemoglobin A1c (HbA(1c)) level of 7.3 % (SD 1.0 %), were randomized (1:1) to groups advised to increase variability of between-injection intervals to 24 +/- up to 3 h or to maintain fixed 24-h intervals for 3 months. Changes of HbA(1c) level and other efficacy and safety measures were assessed. Results: In the fixed-dosing group, 64% of participants reported all intervals within the 23-25-h range, compared with 15% of those advised flexible dosing. In the fixed- and flexible-dosing groups, 12% and 41%, respectively, of between-injection intervals were outside the 23-25-h range, and 2% and 16%, respectively, were outside the 21-27-h range. Least squares mean between-group difference in HbA(1c) change from baseline was 0.05 % (95% confidence interval [CI], -0.13 to 0.23); for fasting plasma glucose, 2.7 mg/dL (95% CI, -9.0 to 14.4); and for daily basal insulin dose, 0.00 U/kg (95% CI, -0.02 to 0.03). Frequencies of hypoglycemia and adverse events did not differ between groups. Conclusions: The efficacy and safety of Gla-300 demonstrated in EDITION 1 and EDITION 2 are maintained in substudies when the insulin was injected up to 3 h before or after the usual time of administration.Peer reviewe

    Antykwariat piosenki [dokument dźwiękowy]

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    11 min, format mp3, 128 kbit/s

    Comparative Study of the Lipophilicity of Selected Anti-Androgenic and Blood Uric Acid Lowering Compounds

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    This study aimed to evaluate the lipophilicity of a series substances lowering the concentration of uric acid in blood and anti-androgen drugs by thin-layer chromatography in reversed-phase systems (RP-TLC, RP-HPTLC) and computational methods. The chromatographic parameter of lipophilicity (RMW) of tested compounds was determined on three stationary phases, i.e., RP18F254, RP18WF254 and RP2F254, using ethanol–water, propan-2-ol-water and acetonitrile–water in various volume compositions as mobile phases. The chromatographic analysis led to determining the experimental value of the lipophilicity parameter for each of the tested compounds, including those for which the experimental value of the partition coefficient (logPexp) as a measure of lipophilicity is not well described in available databases, such as febuxostat, oxypurinol, ailanthone, abiraterone and teriflunomide. The chromatographic parameters of lipophilicity were compared with the logP values obtained with various software packages, such as AClogP, AlogPs, AlogP, MlogP, XlogP2, XlogP3, ACD/logP and logPKOWWIN. The obtained results indicate that, among selected chromatographic parameters of lipophilicity, both experimental and calculated logP values gave similar results, and these RP-TLC or RP-HPTLC systems can be successfully applied to estimate the lipophilicity of studied heterocyclic compounds belonging to two different pharmacological groups. This work also illustrates the similarity and difference existing between the tested compounds under study using the chemometric methods, such as principal component analysis (PCA) and cluster analysis (CA). In addition, a relatively new approach based on the sum of ranking differences (SRD) was used to compare the chromatographically obtained and theoretical lipophilicity descriptors of studied compounds

    Zmiany struktury krystalicznej i magnetycznej poly- i nano- kryształów chromu w funkcji temperatury

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    The magnetic and structural properties of nanocrystalline chromium (n-Cr) were studied by neutron powder diffraction and by synchrotron radiation diffraction techniques. The nanocrystalline Cr is composed of small-sized particles with antiferromagnetic ordering, medium-sized particles with transverse spin density wave (SDW) ordering, and large-sized particles with the same magnetic ordering as bulk Cr. The critical size Dc between the small and medium-sized crystallites is 18±2 nm. The alteration of the magnetic properties of n-Cr is due to microstrain fluctuations which are correlated with the crystallite sizes rather than to the crystallite size itself. The microstrain fluctuations increase the SDW modulation length up to large values (10.5 nm for n-Cr vs 7.8 nm for bulk Cr)

    Nesting of the marsh tit Poecile palustris in pipe fence in the Lower Narew Valley

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