Activities of amine and phenolic antioxidants and their changes in broad beans (Vicia faba) after freezing and steam cooking

Antioxidant properties and changes in the levels of active compounds in fresh and processed broad beans were determined in the study. Activity of extracted substances was much higher against ABTS (2,2'-azino-bis [3-ethylbenzothiazoline-6-sulphonic acid]) than towards DPPH (2,2'-diphenyl-1-picrylhydrazyl) radicals. Phenolics extracted with 70% acetone were also more active comparing to amine compounds obtained with water both in experiments applying radicals and during oxidation of linoleic acid. Steam cooking and freezing had a negative influence on the content of polyphenols and in consequence on their activity. Cooking fresh broad beans decreased the content of those compounds by 16% and freezing – by over 30%, while cooking frozen material resulted in a much lower further decrease (2–8%). Processes applied on fresh material reduced the activity against ABTS^•+ to a smaller extent (cooking by 11% and freezing by around 20%), while cooking frozen beans caused a further decrease by 10–17%.     

A multiscale model of thrombus development

A two-dimensional multiscale model is introduced for studying formation of a thrombus (clot) in a blood vessel. It involves components for modelling viscous, incompressible blood plasma; non-activated and activated platelets; blood cells; activating chemicals; fibrinogen; and vessel walls and their interactions. The macroscale dynamics of the blood flow is described by the continuum Navier-Stokes equations. The microscale interactions between the activated platelets, the platelets and fibrinogen and the platelets and vessel wall are described through an extended stochastic discrete cellular Potts model. The model is tested for robustness with respect to fluctuations of basic parameters. Simulation results demonstrate the development of an inhomogeneous internal structure of the thrombus, which is confirmed by the preliminary experimental data. We also make predictions about different stages in thrombus development, which can be tested experimentally and suggest specific experiments. Lastly, we demonstrate that the dependence of the thrombus size on the blood flow rate in simulations is close to the one observed experimentally.     

The formation of N2O during the reduction of NO by NH3

The process of selective non-catalytic reduction of NO, SNCR, is important for limiting emissions of nitrogen oxides from coal-fired power plants. Such a process has been studied for many years, both in the laboratory and under practical conditions. This work was an attempt at elucidating some of the problems associated with the method when used under circulating fluidized bed (CFB) conditions and in particular, the formation of the N₂O by-product. The NO + NH₃ reaction has been studied in the laboratory, over quartz sand in a heated fixed bed flow reactor. In comparison with a combustion environment, the composition of the gas phase was drastically simplified and limited to NO and NH₃, in nitrogen as the carrier gas, with O2 added in some experiments. The product gases were analyzed for NO, N₂O and NH₃. The effects the following parameters were studied: temperature inside the reactor between 850 and 1250 K, height of the sand bed, NH₃/NO molar ratio over the range 0.54–2.0 and the addition of 1 or 2% of O₂ in volume. Baseline tests with an empty reactor were also made. With no sand in the reactor, the results were both qualitatively and quantitatively different. The sand helped to increase the efficiency of NO reduction, particularly at lower temperatures, but N₂O formation also appeared to be strongly enhanced, except at the highest temperatures. Higher molar NH₃/NO ratios favored NO reduction and N₂O production, both with and without sand. The reduction of NO did not appear to require the presence of O₂, but the introduction of 1% or 2% of O₂ gave some benefit. The results confirmed that under practical conditions more attention should be paid to the role of the bed solids in the SNCR process.     

Synthesis, electrochemical and spectroscopic investigations of New N-BEDOT derivatives containing anil substituted carbazole subunits

A conjugated oligomer containing central bi-ethylenedioxythiophene (BEDOT) unit and two terminal anil-substituted carbazole units has been characterized by cyclic voltammetry and spectroelectrochemical methods (UV-vis-NIR and Raman). It shows two oxidation waves at −0.01 V and +0.24 V (versus Fc/Fc⁺), which can be ascribed to two successive oxidative dopings of the molecule. The molecule is transmissive sharp yellow when fully reduced, transmissive green upon oxidation up to the end of the first oxidative process, and dark blue upon full oxidation. UV-vis-NIR and Raman spectroelectrochemical investigations show that the colour changes within the potential of the first oxidation wave are associated with the oxidation of both carbazole and ethylenedioxythiophene subunits whereas the electrochromic effect in the potential range of the second oxidation wave involves predominantly the oxidation of the ethylenedioxythiophene subunits.     

超超临界参数下的蒸汽侧氧化行为

超超临界（USC）电站提供更高效率和更低排放,是美国能源部先进电力系统计划的目标。在美国,大部分现役燃煤电站的最高运行温度为538℃。然而,全世界新投运的超临界电站蒸汽温度高达620℃。现代先进电力系统的目标包括了煤电效率要达到60％,这需要蒸汽温度高达760℃。本研究调查了在USC系统使用的高级合金的蒸汽氧化作用,重点是高、中压汽轮机部件上使用的合金。本文给出了初步结果。     

Overexpressed yeast mitochondrial putative RNA helicase Mss116 partially restores proper mtRNA metabolism in strains lacking the Suv3 mtRNA helicase

RNA helicase, encoded by the Saccharomyces cerevisiae nuclear gene SUV3, is a subunit of the mitochondrial (mt) degradosome: an enzyme complex that takes part in turnover of mtRNAs. Deletion of the SUV3 gene leads to a variety of disturbances in mtRNA metabolism and results in respiratory incompetence of yeast cells. Here we show that the nuclear gene MSS116, which codes for a mitochondrial putative RNA helicase necessary for splicing of several mt introns, can suppress the lack of the SUV3 gene. Overexpression of the Mss116 putative helicase from a multicopy plasmid present in the SUV3-deleted strains partially restores respiratory competence, brings the steady-state levels of COB and ATP6/8 mRNA back almost to normal and lowers the accumulation of 21S rRNA and ATP6/8 RNA precursors to the wild-type levels. To the best of our knowledge, this is the first reported case of a substitution of one RNA helicase by another, belonging to a different class of RNA helicases.     

FATIGUE CRACK INITIATION LIFE PREDICTION FOR WELDED JOINTS BY LOW CYCLE FATIGUE APPROACH

Abstract— Analytical procedures based on low cycle fatigue theory are used to estimate the fatigue crack initiation life (N_i) for a cruciform welded joint in mild steel under constant amplitude tensile cyclic loading; the fatigue crack initiating at the weld toe. Effects due to welding such as residual stresses, geometrical variability and changes in material properties are handled. It is shown that for high mean stresses the discrepancies observed between the N _i estimates provided by commonly used analytical procedures exceed an order of magnitude. For the base metal (BM) the discrepancies become negligible if cyclic relaxation of notch mean stress is taken into consideration. The differences betwen the N _i estimates for heat affected zone (HAZ) material (where fatigue cracks at the weld toe usually initiate) and for BM are quantified. The applicability of HAZ material properties, estimated from hardness, to N _i prediction is evaluated.     

Kinetics and Mechanisms of Hydrothermal Synthesis of Barium Titanate

Reaction mechanisms for the hydrothermal synthesis of barium titanate are evaluated. Feedstocks of barium hydroxide octahydrate and anatase titania are reacted for varying durations (1–72 h) to provide intermediate-stage samples for characterization by transmission electron microscopy/ energy-dispersive spectroscopy (TEM/EDS), X-ray diffractometry (XRD), and inductively coupled plasma spectroscopy (ICP). Quantitative evaluation of the extent of reaction by ICP and XRD methods permits the analysis of data with the Johnson-Mehl-Avrami equation. This analysis reveals two reaction-rate regimes. Kinetic analysis, based on reaction progress, yields insight into the first reaction-rate regime but is inconclusive in the analysis of the second reaction-rate regime. In the first regime, at the early stage of barium titanate formation, a dissolution-precipitation mechanism dominates. In contrast, in the second regime, at longer reaction times, an in-situ transformation mechanism is probably dominant. However, multiple reaction mechanisms (e.g., in-situ transformation and dissolution-precipitation) may be competing for rate control. Alternatively, dissolution-precipitation may be the dominant mechanism throughout the barium titanate synthesis, with nucleation and growth controlling the first regime and dissolution rate controlling the second regime.     

Changes of Tocopherols and Phospholipids during Heating of Low-Erucic Rapeseed Oil at Temperature Similar to Fritting

Rapeseed oil – crude and refined – and the fraction of acylglycerols isolated from these oils were added to natural amounts of tocopherols or phospholipids and were heated in conditions similar to fritting during 30 hours. Maximum formation of dimers amounted to 24% of initial quantity of tocopherols. In the samples heated at 170°C dimers occurred incidentally, only in model systems of acylglycerols with addition of tocopherols and mainly with big concentration of alphatocopherol. Also the accelerating influence of natural oil components on tocopherol decrease at 170°C was observed.