Sol-gel synthesis,surface and magnetic properties of nanocrystalline SmAlO3

Nanocrystals of single-phase samarium monoaluminate (SmAlO3) were synthesized and studied for the first time. Malic acid was employed as a new complexing agent in the sol-gel process. The material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS), specific surface area and density. The lowest size of the nanoparticles was about 50–60 nm and some of them formed agglomerates. The binding energies of core-level electrons of Sm (3d, 4d, 4f, ...     

Application of pure and mixed probiotic lactic acid bacteria and yeast cultures for oat fermentation

Fermentation of a prebiotic containing oat substrate with probiotic lactic acid bacteria and yeast strains is an intriguing approach for the development of new synbiotic functional products. This approach was applied in the present work by using pure and mixed microbial cultures to ferment a heat‐treated oat mash. Results show that the strains studied were appropriate for oat fermentation and the process could be completed for 6–10 h depending on the strain. The viable cell counts achieved within this time were above the required levels of 10⁶–10⁷ cfu ml⁻¹ for probiotic products. Both single lactic acid bacteria strains and mixed cultures of the same strains with yeast were found suitable for oat fermentation. However, the pure LAB cultures attributed better flavour and shelf life of the oat drinks. The content of the prebiotic oat component beta‐glucan remained within 0.30–0.36% during fermentation and storage of the drinks obtained with each of the strains used. Thus, these products would contribute diet with the valuable functional properties of beta‐glucan. Also, the viability of pure and mixed cultures in the oat products was good: levels of cell counts remained above the required numbers for probiotic products throughout the estimated shelf‐life period. Copyright © 2005 Society of Chemical Industry     

Variational and numerical approach to a steady-state rolling problem

A steady-state rolling problem with rigid–plastic, incompressible material and nonlocal Coulomb-contact friction condition is considered. The corresponding primal, penalty and regularized penalty variational formulations are presented and studied. It is shown that the solutions of the penalty and regularized penalty variational problems converge to the solutions of the primal and penalty variational problems, when the penalty and regularization parameters tend to zero. The finite-element approximation of the regularized penalty problem is presented and analysed. An algorithm, combining the finite-element method with convergent successive iterations method of secant-modulus is proposed and applied to solve an illustrative example.     

Sm3+ photoluminescence in co-sputtered SiO2 thin films

Thin films of SiO₂ containing Sm were deposited by magnetron co-sputtering. The concentration of Sm in the films was varied by changing the amount of Sm placed on the fused silica target. The samarium content in the films was established by Rutherford back-scattering measurements. Photoluminescence (PL) was excited with the 488-nm line of an Ar ion laser. It consists of several lines in the visible, which are assigned to transitions between multiplets of Sm³⁺. The concentration dependence of the PL intensity was studied. It passes through a maximum and decreases at higher Sm content. The films were annealed in vacuum at temperatures between 300 and 1000 °C. There was a strong increase in the PL intensity after annealing at 600 °C, and then it fell again after annealing at 1000 °C. The data are compared to spectra of Sm³⁺ in other matrices. The mechanisms of PL excitation and quenching are discussed.     

Investigation of antioxidant activity and lipophilicity parameters of some preservatives

The preservatives have been widely used in food, drugs and cosmetic products to prevent their aging and decay. Antioxidant and antimicrobial activities of some preservatives, such as benzoic acid, sorbic acid and alkyl-parabens, were considered in this work. Study of antioxidant properties of these compounds was carried out by differential pulse voltammetry together with evaluation of their influence on the kinetics of the electrochemical oxygen reduction. Mathematical models of the processes were obtained and their adequacy was estimated using design of experiment methods. As a result, the kinetic parameters of interaction between reactive oxygen species and preservatives were evaluation. Finally, the use of these substances as antimicrobials and antioxidants ensured product stability and safety has been recommended.     

Einführung des neuen Zugsicherungssystems ERTMS/ETCS aus der Sicht eines Herstellers

The new European train control system ERTMS/ETCS now goes from the phase of system specifications into the phase of test and trials within pilot projects supported by the EU. The first commercial installations are being prepared. Alcatel Austria has participated in the test project on the Vienna-Budapest line and now has started its first ETCS level 1 installation on parts of the Sofia-Burgas line in Bulgaria. The status of this work, some of the problems and technical solutions met during the introduction of the new system are being discussed.     

Purely analytical extraction of an improved nonlinear FinFET model including non-quasi-static effects

An analytical procedure is proposed for extracting a new nonlinear FinFET model, which accounts for non-quasi static effects. The accuracy and the robustness of the obtained nonlinear model are completely validated through the comparison between simulated and measured device behaviour in both linear and nonlinear cases. This study clearly shows that the inclusion of the non-quasi-static phenomena leads to significant model simulation improvements, which become more pronounced at higher frequency.     

Incorporation of Nucleoside Probes Opposite O6‐Methylguanine by Sulfolobus solfataricus DNA Polymerase Dpo4: Importance of Hydrogen Bonding

O⁶‐Methylguanine (O⁶‐MeG) is a mutagenic DNA lesion, arising from the action of methylating agents on guanine (G) in DNA. Dpo4, an archaeal low‐fidelity Y‐family DNA polymerase involved in translesion DNA synthesis (TLS), is a model for studying how human Y‐family polymerases bypass DNA adducts. Previous work showed that Dpo4‐mediated dTTP incorporation is favored opposite O⁶‐MeG rather than opposite G. However, factors influencing the preference of Dpo4 to incorporate dTTP opposite O⁶‐MeG are not fully defined. In this study, we investigated the influence of structural features of incoming dNTPs on their enzymatic incorporation opposite O⁶‐MeG in a DNA template. To this end, we utilized a new fluorescence‐based primer extension assay to evaluate the incorporation efficiency of a panel of synthetic dNTPs opposite G or O⁶‐MeG by Dpo4. In single‐dNTP primer extension studies, the synthetic dNTPs were preferentially incorporated opposite G, relative to O⁶‐MeG. Moreover, pyrimidine‐based dNTPs were generally better incorporated than purine‐based syn‐conformation dNTPs. The results suggest that hydrophobicity of the incoming dNTP appears to have little influence on the process of nucleotide selection by Dpo4, with hydrogen bonding capacity being a major influence. Additionally, modifications at the C2‐position of dCTP increase the selectivity for incorporation opposite O⁶‐MeG without a significant loss of efficiency.     

Effect of layered silicates on fibril formation and properties of PCL/PLA microfibrillar composites

The study deals with improvement of poly(?‐caprolactone) (PCL) parameters by in situ forming of poly(lactic acid) (PLA) fibrils. This structure is achieved by preparation of the melt‐drawn microfibrillar composite (MFC) from the PCL/PLA 80/20 blend containing the organophilized montmorillonite (oMMT) added using various mixing protocols. Improved mechanical behavior corresponds to the micron‐sized fibrils formation and reinforcement of both polymer components by oMMT, and to increased crystalline phase content in the fibrillar PLA phase. Effective melt drawing is only possible after the rheological parameters of the polymer components have been modified by oMMT where the clay addition method and content are of primary importance. From the results obtained, it follows that the role of oMMT in MFC is quite complex, numerous clay‐induced effects may be contradictory and must be harmonized to achieve PCL‐based biodegradable MFCs with improved parameters. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43061.