Enzymatically Extracted Apple Pectin Possesses Antioxidant and Antitumor Activity

The biological activity of apple pectin extracted conventionally or enzymatically using endo-xylanase and endo-cellulase, was tested in vitro. The analyses were performerd in tetraplicates and the statistical significance of the differences were assessed using ANOVA, Tukey post hoc and LSD (the least significant difference) tests. Multivariate regression analysis was applied to determine the structural components that have a crucial importance for antioxidant and antitumor properties of pectins. The pectins extracted by enzymes contained up to four times more ferulic acid and showed twice as great ability to neutralize free radicals and Fe(III) reduction. The antiradical potential positively correlated with phenols, fucose and rhamnose content. In the assays performed on HT-29 human adenocarcinoma and B16F10 melanoma cell cultures, the “green” pectins, contrary to acid isolated ones, exhibited remarkable anti-neoplastic potential while being nontoxic to nontransformed L929 cell line. The pectins in the dose of 1 mg/mL were capable of inhibiting adhesion (max 23.1%), proliferation (max 40.4%), invasion (max 76.9%) and anchorage-independent growth (max 90%) of HT-29 cells (significance level p < 0.001). These pectin preparations were slightly less active towards B16F10 cells. The enzyme-isolated apple pectins may be useful as a functional food additive and an ingredient of the ointment formulas for post-surgical melanoma treatment.     

Competing symmetries and broken bonds in superconducting vortex-antivortex molecular crystals

Hall probe microscopy has been used to image vortex-antivortex molecules induced in superconducting Pb films by the stray fields from square arrays of magnetic dots. We have directly observed spontaneous vortex-antivortex pairs and studied how they interact with added free (anti)fluxons in an applied magnetic field. We observe a variety of phenomena arising from competing symmetries which either drive added antivortices to join antivortex shells around dots or stabilize the translationally symmetric antivortex lattice between the dots. Added vortices annihilate antivortex shells, leading first to a stable "nulling state" with no free fluxons and then, at high densities, to vortex shells around the dots stabilized by the asymmetric antipinning potential. Our experimental findings are in good agreement with Ginzburg-Landau calculations.     

Inhibition of copper corrosion in acidic sulphate media by eco-friendly amino acid compound

This investigation aimed to study a “green” non-toxic biodegradable copper corrosion inhibitor in an acidic sodium sulphate solution. The methods used in the investigation of cysteine as a copper corrosion inhibitor in an acidic sodium sulphate solution were: potentiodynamic measurements, open circuit potential measurements, and chronoamperometric measurements. Optical microscopy was used in addition to electrochemical methods. Potentiodynamic measurements show that cysteine has good inhibitory properties in an acidic medium. Polarisation curves indicate that the presence of cysteine in a sulphate solution decreases the current density and that using various cysteine concentrations results in the formation of a protective film on the surface of the electrode due to the formation of the Cu(I)-cys complex. These results are confirmed by chronoamperometric measurements. Furthermore, it is clear from microphotographs that a protective film does form on copper electrode in the presence of cysteine. The Langmuir adsorption isotherm indicates that cysteine is chemisorbed on the surface of the electrode.     

Application of Deep Eutectic Solvents in the Synthesis of Substituted 2-Mercaptoquinazolin-4(3H)-Ones: A Comparison of Selected Green Chemistry Methods

In this study, deep eutectic solvents (DESs) were used as green and eco-friendly media for the synthesis of substituted 2-mercaptoquinazolin-4(3H)-ones from different anthranilic acids and aliphatic or aromatic isothiocyanates. A model reaction on anthranilic acid and phenyl isothiocyanate was performed in 20 choline chloride-based DESs at 80 °C to find the best solvent. Based on the product yield, choline chloride:urea (1:2) DES was found to be the most effective, while DESs acted both as solvents and catalysts. Desired compounds were prepared with moderate to good yields using stirring, microwave-assisted, and ultrasound-assisted synthesis. Significantly, higher yields were obtained with mixing and ultrasonication (16–76%), while microwave-induced synthesis showed lower effectiveness (13–49%). The specific contribution of this research is the use of DESs in combination with the above-mentioned green techniques for the synthesis of a wide range of derivatives. The structures of the synthesized compounds were confirmed by ¹H and ¹³C NMR spectroscopy.     

Determining elemental strontium distribution in rat bones treated with strontium ranelate and strontium citrate using 2D micro-XRF and 3D dual energy K-edge subtraction synchrotron imaging

Strontium-based medications, such as strontium ranelate, have been suggested to have therapeutic effects in patients with osteoporosis. Strontium salts available off-shelf in stores across North America are assumed to provide similar effects as strontium ranelate and thus should lead to similar distributions of elemental strontium incorporated in bone. The objective of this study was to compare the spatial distribution of strontium in animal bones following the administration of strontium ranelate and strontium citrate. Seventeen-week-old Sprague–Dawley rats were split into three groups over 10 weeks and given 625 mg/kg/day of strontium ranelate and 676 mg/kg/day of strontium citrate; the control group received no additional supplementary strontium. The humeri were collected from all animals, and strontium distribution was mapped using 2D micro-XRF and 3D dual energy K-edge subtraction (KES) imaging. 2D and 3D elemental mapping methods demonstrated that strontium delivered during treatment by both salts had the same spatial distribution. 3D elemental strontium maps of treated animal bones showed that strontium was largely observed in the trabecular regions under the epiphyseal (growth) plate. The thickness of the strontium layers in both the strontium ranelate and strontium citrate sample was not significantly different (p = .9201). 2D micro-XRF and 3D dual-energy KES images effectively elucidated the spatial distribution of elemental strontium in calcified tissue. These methods provide a novel approach to evaluating the potential efficacy of strontium supplements in the treatment of osteoporosis.     

Regge oscillations in integral cross sections for proton impact on atomic hydrogen

The integral cross sections for elastic scattering and spin exchange for proton impact on atomic hydrogen show several oscillations in the energy range 0.01-1.0 eV that cannot be associated with resonances or the glory effect. A complex angular momentum analysis using computed Regge trajectories shows that each peak of the oscillatory structure is predominantly associated with at most three trajectories. In this way, the peaks are related to the L=0 bound states of H+ 2. The complex angular momentum theory for integral cross sections that we introduce shows that such oscillations are a general feature of potential scattering.     

Mechanism of hopping transport in disordered mott insulators

By using a combination of detailed experimental studies and simple theoretical arguments, we identify a novel mechanism characterizing the hopping transport in the Mott insulating phase of Ca2-xSrxRuO4 near the metal-insulator transition. The hopping exponent alpha shows a systematic evolution from a value of alpha=1/2 deeper in the insulator to the conventional Mott value alpha=1/3 closer to the transition. This behavior, which we argue to be a universal feature of disordered Mott systems close to the metal-insulator transition, is shown to reflect the gradual emergence of disorder-induced localized electronic states populating the Mott-Hubbard gap.     

Thermal collapse of spin polarization in half-metallic ferromagnets

We propose two novel approaches to study the temperature dependence of the magnetization and the spin polarization at the Fermi level in magnetic compounds, and apply them to half-metallic ferromagnets. We reveal a new mechanism, where the hybridization of states forming the half-metallic gap depends on thermal spin fluctuations and the polarization can drop abruptly at temperatures much lower than the Curie point. We verify this for NiMnSb by ab initio calculations. The thermal properties are studied by mapping ab initio results to an extended Heisenberg model which includes longitudinal fluctuations and is solved by a Monte Carlo method.