Project proposal for the investigation of particle-stabilised emulsions and foams by microgravity experiments

The utilisation of particle-surfactants nanostructures as stabilising agents represents today the technologic and scientific frontier in the stabilisation of liquid films in emulsion and foams. This topic will be addressed by the proposal STEFAN (STabilisation of Emulsions and FoAms by Nanoparticles), proposed by European groups in the framework of the ESA AO-2004 for Life and Physical Sciences and Applied Research projects Similarly to what can be observed for surfactant-stabilised emulsions and foams, microgravity provides ideal conditions for the investigation of the hierarchy of involved objects: interfacial layer, liquid film, dispersed systems foam or emulsion. Microgravity experiments are planned by refurbishing the Experimental Container FASES for the ISS Fluid Science Laboratory and the facility FASTER for the European Drawer Rack, already under development in existing research programmes. Here the scientific guidelines of the project are presented together with examples and preliminary results on the effect of nano-particle-surfactant structures adsorbed at liquid interfaces. First experimental results have been achieved for particle monolayers at the water/air interface and a thermodynamic model was derived to describe the obtained surface pressure-area isotherms.     

Soil management effects on aggregate dynamics in semiarid Aragon (NE Spain)

During decades, in semiarid rainfed Aragon, intensive soil tillage and low crop residue input have led to the loss of soil structure and soil degradation. Conservation tillage and cropping intensification can improve soil structure in these areas. The objective of this study was to determine the influence of three different tillage systems (traditional tillage, reduced tillage and no-tillage) under two cropping systems (fallow-barley rotation and barley monoculture) on soil aggregation dynamics during a cropping season. A decrease in tillage intensity resulted in a higher mean size of dry aggregates and a greater water aggregate stability in both cropping systems particularly under no-tillage.     

MQDM: An Iterative Fuzzy Method for Group Decision Making in Structured Social Networks

Modern human societies have evolved into an almost entirely connected world, giving place to a remarkable increase in social interactions. In this new context and because of the globalization of all human activities, the collective participation in decision‐making processes takes an increasingly prominent role. In this paper, a method for group decision making from a set of imprecise opinions called “moviQuest Decision Making” (MQDM), is presented. This method allows to integrate the opinions of heterogeneous groups of agents in a structured social network along a sequence of voting rounds for collective decision making.     

Separation of recombinant human erythropoietin glycoforms by capillary electrophoresis using volatile electrolytes. Assessment of mass spectrometry for the characterization of erythropoietin glycoforms

The separation of the glycoforms of erythropoietin (EPO) by capillary electrophoresis (CE) was recently published as a monograph by the European Pharmacopoeia (European Pharmacopoeia 4 2002, 1316, 1123-1128). Although the experimental CE conditions employed a background electrolyte containing additives suitable for on-line UV-absorption detection, they were not appropriate for on-line mass spectrometry (MS) detection. In this work, an attempt was made to investigate experimental conditions employing volatile electrolyte systems to achieve the separation and characterization of EPO glycoforms using CE and ESI-MS methodologies. The influence of several operating conditions, such as the coating of the internal walls of the capillary as well as the composition, concentration, and the pH of the separation buffer were investigated. The results demonstrated that when the internal walls of the capillaries were permanently coated with Polybrene and a buffer electrolyte containing 400 mM of HAc-NH4Ac (acetic acid-ammonium acetate), pH 4.75, was used, a significantly reproducible separation was achieved for EPO glycoforms. Intact EPO was characterized by two mass spectrometry techniques: electrospray ionization (ESI-MS) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF-MS). The data demonstrated that MALDI-TOF-MS provided a good approximation to an average molecular mass of the EPO molecule. However, it was still necessary to carry out further separation of the intact EPO glycoforms in order to obtain molecular mass information when ESI-MS was used.     

Time-resolved optical sensing of oligonucleotide hybridization via Au colloidal nanoparticles

Au nanoparticles have distinctive absorption spectra whose peak position or particle plasmon resonance wavelength is highly sensitive to molecule adsorption on their surfaces. Spherical Au nanoparticles are surface-modified by amino-functionalized self-assembly-monolayer and used as optical probes in the fluorescence-label-free spectroscopic detection of sub-nanomole oligonucleotides. Time-resolved studies of the immobilization and hybridization of oligonucleotides on the surface of Au nanoparticles were carried out. By measuring peak shift of absorption spectra of the Au colloidal nanoparticles over time, the samples of 15 nM 20 mer target and mismatched oligonucleotides are distinguished by their different influences on the particle plasmon resonance wavelength. The approach presented in this paper extends the application of Au nanoparticles as the optical probe in oligonucleotide recognitions without prior sample labeling.     

Construction of a Fuzzy and Boolean Logic Gates Based on DNA

Logic gates are devices that can perform logical operations by transforming a set of inputs into a predictable single detectable output. The hybridization properties, structure, and function of nucleic acids can be used to make DNA‐based logic gates. These devices are important modules in molecular computing and biosensing. The ideal logic gate system should provide a wide selection of logical operations, and be integrable in multiple copies into more complex structures. Here we show the successful construction of a small DNA‐based logic gate complex that produces fluorescent outputs corresponding to the operation of the six Boolean logic gates AND, NAND, OR, NOR, XOR, and XNOR. The logic gate complex is shown to work also when implemented in a three‐dimensional DNA origami box structure, where it controlled the position of the lid in a closed or open position. Implementation of multiple microRNA sensitive DNA locks on one DNA origami box structure enabled fuzzy logical operation that allows biosensing of complex molecular signals. Integrating logic gates with DNA origami systems opens a vast avenue to applications in the fields of nanomedicine for diagnostics and therapeutics.     

Identification of Host Attractants for the Ethiopian Fruit Fly, <Emphasis Type="Italic">Dacus ciliatus</Emphasis> Loew

The Ethiopian fruit fly, Dacus ciliatus, is an oligophagous pest of cucurbit crops, particularly melons, cucumbers, and marrows (summer squash). The present study aimed to identify host attractants for D. ciliatus and was guided by a behavioral bioassay and an electrophysiological assay. We tested volatile compounds from the fruits of a host plant, ripe and unripe Galia melon, Cucumis melo var. reticulates. Both sexes were attracted to melon volatiles. Those of ripe melon were preferred. Gas chromatography-electroantennographic detection analysis of the behaviorally active ripe melon volatiles consistently showed that 14 compounds elicited similar antennal responses from both sexes. Twelve compounds were identified by gas chromatography-mass spectrometry (GC-MS) using GC-MS libraries, retention indices (RI), and authentic standards. The electrophysiological activities of the compounds that were present at sufficient levels for identification, benzyl acetate, hexanyl acetate, (Z)-3-hexenyl acetate, (Z)-3-octenyl acetate, octanyl acetate, (Z)-3-decenyl acetate, and (E)-β-farnesene, were evaluated at six different dosage levels by using electroantennography (EAG). Benzyl and hexanyl acetates elicited dose responses only in males, while other tested compounds elicited dose responses in both sexes. The strongest responses were observed for doses between 100 ng and 10 μg. The dose response, in terms of attractiveness to synthetic compounds within the active range (as determined by EAG), also was evaluated in the behavioral bioassay. Synthetic acetates were attractive to both sexes when tested individually. Significant attraction was observed when individual compounds were applied in the bioassay arena at doses of 0.5–1 μg/dispenser. Blends of compounds in equal proportions also were attractive to the insects. The most attractive blend was a mixture of four or five identified acetates. The addition of an equal proportion of (E)-β-farnesene to this mixture had a deterrent effect.     

Who said what? Source memory for narrator and character agents in literary short stories.

One dimension of reading literacy involves the tracking of agents associated with the text. In a literary short story, there is a society of character agents and pragmatic agents. This study investigated the relative salience of different classes of agents in memory. Two experiments measured source memory as an index of agent salience in long-term memory. Patterns of source memory scores supported an invisible third-person narrator hypothesis and an agent amalgamation hypothesis, but not a structural prominence hypothesis: First-person narrator > nonnarrator character > third-person narrator > 0. Statement detection parameters did not significantly differ among the 3 classes of agents, so differences in source memory could not be explained by differences in the content of the speech acts. Source memory scores also could not be explained by surface features of the text, differences among readers, and sophisticated guessing on the basis of a story abstract. (PsycINFO Database Record (c) 2010 APA, all rights reserved)