Chemical composition of currant seed extracts and their protective effect on human lymphocytes DNA

On the basis of LC/UV/MS analysis, 35 compounds from the extracts of seeds of black, red, and white currants (2 cultivars of each) were identified. Black currants cultivars contained protocatechuic acid and p-hydroxybenzoic acid, and traces of nitril containing phenolic acids. The presence of synapoyl glucoside was characteristic for cv. Malling Jewel. Sesquiterpenoid glycosides and carboxymethylindol glycosides were present mainly in white and red currant cultivars. Blackcurrant seeds contained higher amounts of flavonoids, especially rutin, isoquercetin, and taxifolin. The currant seed extracts were tested for in vitro protective effect on chromosome aberrations in peripheral human lymphocytes using cytochalasin-B blocked micronucleus (CBMN) assay. The frequency of MN was scored in binucleated cells, and the cultivars of black currants showed the best antioxidant potential. At a concentration of only 0.17 mg/mL, extract of the seed cv. Malling Jewel effected a decrease in the frequency of MN of 60% compared with control cell cultures. PRACTICAL APPLICATION: Our results provide evidence of protective effects of currant seed extracts and isolated pure compounds on cytogenetic damages in human lymphocytes. Thus, currant seed extracts could exert beneficial effects in quite a few diseases, for many of the biological actions have been attributed to their antioxidant properties.     

Nodes on ropes: a comprehensive data and control flow for steering ensemble simulations

Flood disasters are the most common natural risk and tremendous efforts are spent to improve their simulation and management. However, simulation-based investigation of actions that can be taken in case of flood emergencies is rarely done. This is in part due to the lack of a comprehensive framework which integrates and facilitates these efforts. In this paper, we tackle several problems which are related to steering a flood simulation. One issue is related to uncertainty. We need to account for uncertain knowledge about the environment, such as levee-breach locations. Furthermore, the steering process has to reveal how these uncertainties in the boundary conditions affect the confidence in the simulation outcome. Another important problem is that the simulation setup is often hidden in a black-box. We expose system internals and show that simulation steering can be comprehensible at the same time. This is important because the domain expert needs to be able to modify the simulation setup in order to include local knowledge and experience. In the proposed solution, users steer parameter studies through the World Lines interface to account for input uncertainties. The transport of steering information to the underlying data-flow components is handled by a novel meta-flow. The meta-flow is an extension to a standard data-flow network, comprising additional nodes and ropes to abstract parameter control. The meta-flow has a visual representation to inform the user about which control operations happen. Finally, we present the idea to use the data-flow diagram itself for visualizing steering information and simulation results. We discuss a case-study in collaboration with a domain expert who proposes different actions to protect a virtual city from imminent flooding. The key to choosing the best response strategy is the ability to compare different regions of the parameter space while retaining an understanding of what is happening inside the data-flow system.     

Design of Mobile Phones for Older Adults: An Empirical Analysis of Design Guidelines and Checklists for Feature Phones and Smartphones

Design guidelines and checklists are suggested as a useful tool in the development and evaluation of interface design of mobile phones for older adults. Given the intense evolution of mobile phone design, understanding how the design guidelines and checklists have taken into account the advances in mobile phone usability for older adults is important for their correct application and future development. Thus, this study explores the usability dimensions of mobile phone design for older adults and the related changes in terms of time and the type of device (feature phones vs. smartphones) based on an expert coding of the eight mobile phone design guidelines and checklists for older adults published between 2006 and 2014. The results of the expert coding show that design guidelines and checklists most frequently deal with visual and haptic issues (e.g., high contrast, button type, and button size), whilst they hardly ever address various elements of textual interface (e.g., ease of text entry, a button’s feedback, and font type). Over time, the design guidelines and checklists have become more complex in terms of the average number of included usability categories and dimensions. For smartphones, the guidelines, on average, put more emphasis on the screen, touchscreen, text, and exterior related issues, whereas the design guidelines for feature phones stress the usability of the keypad and menus. Besides revealing potential usability dimensions that could be further expanded in the guidelines, this study also highlights the need for research that would empirically validate the design guidelines and checklists in the future.     

Adsorption–desorption noise in plasmonic chemical/biological sensors for multiple analyte environment

We investigated intrinsic noise in plasmonic sensors caused by adsorption and desorption of gaseous analytes on the sensor surface. We analyzed a general situation when there is a larger number of different analyte species. We applied our model to calculate various analyte mixtures, including some environmental pollutants, toxic and dangerous substances. The spectral density of mean square refractive index fluctuations follows a dependence similar to that of generation-recombination noise in photodetectors, flat at lower frequencies and sharply decreasing at higher. Some of the calculated noise levels are well within the detection range of conventional surface plasmon resonance sensors. An AD noise peak is observed in temperature dependence of mean square refractive index fluctuations, thus sensor operating temperature may be optimized to obtain larger signal to noise ratio. A significant property of AD noise is its rise with the decreasing plasmon sensor area, which means that it will be even more pronounced in modern nanoplasmonic devices. Our consideration is valid both for conventional surface plasmon resonance devices and for general nanoplasmonic devices.     

Collaborative spaces for GIS-based multimedia cartography in blended environments

The interaction spaces between instructors and learners in the traditional face-to-face classroom environment are being changed by the diffusion and adoption of many forms of computer-based pedagogy. An integrated understanding of these evolving interaction spaces together with how they interconnect and leverage learning are needed to develop meaningful strategies for effective teaching and learning. The 18i collaborative interaction spaces model was designed based on constructivist principles, and describes 18 mixed instructor–learner spaces contextualized at a finer operational scale that makes explicit a wider range of interactions. The model was implemented during the life cycle of an undergraduate GIS-based multimedia cartography course. One output was the generation of a repository of rule-based trajectory plans for rapid planning and problem solving. The model provides an integrated workflow to manage course contents, products, interactions, individuality, and learning styles in blended environments.     

Pt/C doped by MoOx as the electrocatalyst for oxygen reduction and methanol oxidation

The oxidation of methanol and reduction of oxygen were studied on MoO_x–Pt/C nano-catalysts prepared by the polyole method combined by MoO_x post-deposition. The catalysts were characterized by TEM and EDX. The presented composition of the electrode is very similar to the nominal ones and post-deposited MoO_x species block only a small fraction of the active Pt particle surface area. MoO_x deposition on the carbon support can be ruled out from the EDX results and the low mobility of these oxides at corresponding conditions. The electrode catalytic activity in the electrooxidation of methanol and the reduction of oxygen was studied by steady-state voltammetry and cyclic voltammetry. MoO_x–Pt/C catalyst exhibits higher catalytic activity than Pt/C for the oxygen reduction. The catalytic effect in oxidation of methanol is achieved only under potentiodynamic conditions, when poisoning species have no enough time to develop fully.     

Recovery of flavonoids from grape skins by enzyme-assisted extraction

Grape skin contains large amounts of different flavonoids so it can be used for their recovery. Optimization of enzyme-assisted extraction of flavonoids was conducted using oenological enzyme preparations with respect to enzyme dosage, temperature, extraction time, pH, and enzyme preparation. Optimal conditions were obtained using enzyme preparation Lallzyme EX-V, at the temperature of 45°C, time of 3 h, pH 2.0, and enzyme dosage of 10.52 mg/g. The new optimized extraction method is less expensive, simple, accurate, and selective for the recovery of simple flavonoids. It is based on an environmentally-friendly extraction solvent which may provide a valuable alternative to conventional methods.     

Simultaneous oxidation of aromatic compounds using Sr-doped lanthanum manganites as catalysts

Strontium-doped lanthanum manganites, La_1-xSr_xMnO₃ (LSMO), are promising and affordable catalysts for oxidative degradation of volatile organic compounds. LSMO catalysts (x = 0, .1, .2, and .3) were prepared by the citrate-nitrate autocombustion (CNA) and coprecipitation synthesis. The phase composition was confirmed by X-ray diffraction and Rietveld refinement analysis, while the oxygen content was determined by Mohr's salt permanganate titration. Morphology and porosity of prepared catalysts was correlated to catalytic oxidation of benzene, toluene, ethylbenzene and o-xylene. It was observed that both synthesis methods yielded catalysts of similar average pore size diameter and specific surface area, but the pore size distribution differed: CNA-prepared catalysts had a multimodal pore size distribution, while the coprecipitated ones had a single maximum at 4 nm. Catalysts prepared by the CNA method have shown a higher catalytic activity in the temperature range 373–723 K, as the presence of Mn³⁺/Mn⁴⁺ mixed valences increased their reducibility.     

Potential of proton-enhanced 13C n.m.r. for the classification of kerogens

High resolution n.m.r. spectroscopy, involving the technique of cross-polarization, along with magicangle spinning, was used in the structural characterization of eight kerogens of different origins, selected to represent the three types of kerogens (types I–III evolution paths). The influence of cross-polarization dynamics on the sensitivity of the method and the ratio of individual fractions in the spectrum was studied in more detail. It is suggested that an analysis of the influence of the mixing time is necessary prior to definitive characterization of any sample. Good separation of signals in aliphatic, aromatic, and carboxylic regions was achieved. The general correlation between the ¹³C n.m.r. structural characteristics and the classification based on ultimate analysis of the kerogens (types I–III, van Krevelen atomic H/C vs. O/C diagrams) was found to be satisfactory. The structural features of kerogens derived from ¹³C n.m.r. analysis agreed quite well with characteristics constituting the above mentioned classification. The ¹³C n.m.r. method used in this paper may be considered promising in the classification of kerogens.     

Large-scale parallel arrays of silicon nanowires via block copolymer directed self-assembly

Extending the resolution and spatial proximity of lithographic patterning below critical dimensions of 20 nm remains a key challenge with very-large-scale integration, especially if the persistent scaling of silicon electronic devices is sustained. One approach, which relies upon the directed self-assembly of block copolymers by chemical-epitaxy, is capable of achieving high density 1?:?1 patterning with critical dimensions approaching 5 nm. Herein, we outline an integration-favourable strategy for fabricating high areal density arrays of aligned silicon nanowires by directed self-assembly of a PS-b-PMMA block copolymer nanopatterns with a L(0) (pitch) of 42 nm, on chemically pre-patterned surfaces. Parallel arrays (5 × 10(6) wires per cm) of uni-directional and isolated silicon nanowires on insulator substrates with critical dimension ranging from 15 to 19 nm were fabricated by using precision plasma etch processes; with each stage monitored by electron microscopy. This step-by-step approach provides detailed information on interfacial oxide formation at the device silicon layer, the polystyrene profile during plasma etching, final critical dimension uniformity and line edge roughness variation nanowire during processing. The resulting silicon-nanowire array devices exhibit Schottky-type behaviour and a clear field-effect. The measured values for resistivity and specific contact resistance were ((2.6 ± 1.2) × 10(5)Ωcm) and ((240 ± 80) Ωcm(2)) respectively. These values are typical for intrinsic (un-doped) silicon when contacted by high work function metal albeit counterintuitive as the resistivity of the starting wafer (～10 Ωcm) is 4 orders of magnitude lower. In essence, the nanowires are so small and consist of so few atoms, that statistically, at the original doping level each nanowire contains less than a single dopant atom and consequently exhibits the electrical behaviour of the un-doped host material. Moreover this indicates that the processing successfully avoided unintentional doping. Therefore our approach permits tuning of the device steps to contact the nanowires functionality through careful selection of the initial bulk starting material and/or by means of post processing steps e.g. thermal annealing of metal contacts to produce high performance devices. We envision that such a controllable process, combined with the precision patterning of the aligned block copolymer nanopatterns, could prolong the scaling of nanoelectronics and potentially enable the fabrication of dense, parallel arrays of multi-gate field effect transistors.