Differential Attractiveness of Potato Tuber Volatiles to <Emphasis Type="Italic">Phthorimaea operculella</Emphasis> (Gelechiidae) and the Predator <Emphasis Type="Italic">Orius insidiosus</Emphasis> (Anthocoridae)

The behavioral responses of the potato tuberworm moth Phthorimaea operculella and the polyphagous predator Orius insidiosus to volatiles emanating from exposed tubers were studied by four-arm olfactometer bioassays. Mated females of P. operculella distinguished volatiles released by intact potato tubers from volatiles damaged mechanically or by conspecific larvae. Volatiles from intact potato tubers were attractive to them. On the other hand, unmated females of P. operculella did not respond to tuber volatiles. Adults of O. insidiosus were attracted to volatiles from tubers damaged by P. operculella larvae, but did not respond to intact or mechanically damaged tubers. Methyl jasmonate (MeJA) was the only compound identified from the headspace of potato tubers (GC-MS of direct headspace sampling). The amount varied with the type of induction, being 0.001 ± 0.0003 ng g⁻¹ in tissues of intact fresh tubers, 0.002 ± 0.0007 ng g⁻¹ in mechanically damaged tubers, and showing a six- to tenfold increase in P. operculella damaged tubers (0.090 ± 0.006 ng g⁻¹). Behavioral bioassays with synthetic MeJA confirmed that the response of the insects is dependent on MeJA concentration. Mated females of P. operculella showed the highest response at 0.001 ng g⁻¹ (concentration released by intact tubers), whereas O. insidiosus showed the highest response, between 0.01 and 0.05 ng g⁻¹, which is close to the concentration released by P. operculella damaged tubers. Based on these results, we postulate that P. operculella and O. insidiosus have adapted their responses to plant volatiles differently, enabling them to locate suitable hosts or prey.     

Flexible ZnO-cellulose nanocomposite for multisource energy conversion

Materials with the ability to harness multiple sources of energy from the ambient environment could lead to new types of energy-harvesting systems. It is demonstrated that nanocomposite films consisting of zinc oxide nanostructures embedded in a common paper matrix can be directly used as energy-conversion devices to transform mechanical and thermal energies to electric power. These mechanically robust and flexible devices can be fabricated over large areas and are capable of producing an output voltage and power up to 80 mV and 50 nW cm(-2) , respectively. Furthermore, it is shown that by integrating a certain number of devices (in series and parallel) the output voltage and the concomitant output power can be significantly increased. Also, the output voltage and power can be enhanced by scaling the size of the device. This multisource energy-harvesting system based on ZnO nanostructures embedded in a flexible paper matrix provides a simplified and cost-effective platform for capturing trace amounts of energy for practical applications.     

Pavlovian to instrumental transfer of control in a human learning task.

Pavlovian learning tasks have been widely used as tools to understand basic cognitive and emotional processes in humans. The present studies investigated one particular task, Pavlovian-to-instrumental transfer (PIT), with human participants in an effort to examine potential cognitive and emotional effects of Pavlovian cues upon instrumentally trained performance. In two experiments, subjects first learned two separate instrumental response-outcome relationships (i.e., R1-O1 and R2-O2) and then were exposed to various stimulus-outcome relationships (i.e., S1-O1, S2-O2, S3-O3, and S4-) before the effects of the Pavlovian stimuli on instrumental responding were assessed during a non-reinforced test. In Experiment 1, instrumental responding was established using a positive-reinforcement procedure, whereas in Experiment 2, a quasi-avoidance learning task was used. In both cases, the Pavlovian stimuli exerted selective control over instrumental responding, whereby S1 and S2 selectively elevated the instrumental response with which it shared an outcome. In addition, in Experiment 2, S3 exerted a nonselective transfer of control effect, whereby both responses were elevated over baseline levels. These data identify two ways, one specific and one general, in which Pavlovian processes can exert control over instrumental responding in human learning paradigms, suggesting that this method may serve as a useful tool in the study of basic cognitive and emotional processes in human learning. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Synthesis of star poly(N-isopropylacrylamide) by β-cyclodextrin core initiator via ATRP approach in water

Star poly(N-isopropylacrylamide) (PNIPAAm) based on a β-cyclodextrin (β-CD) core macroinitiator was synthesized by means of atomic transfer radical polymerization (ATRP) in water using copper(I)/2,2bipyridyl complex as a catalytic system at temperature above the lower critical solution temperature (LCST) of the PNIPAAm. The macroinitiator was prepared by the transesterification reaction of the (β-CD) with 2-bromopropionyl bromide. The LCST of the samples upshifts slightly when the absolute molecular mass of the star PNIPAAm increases. Over the phase transition, the solutions became bluish opalescent due to formation of a heterogeneous phase system consisting of collapsed polymer particles in water. Atomic force microscopy and dynamic light scattering analyses indicated two populations of self-assembled polymer structure: a larger population and a smaller population. The smaller size suggests to self-assembly of polymer micelles and the large one corresponds to aggregates of polymer micelles or star polymers coupled. Polydispersity of the star PNIPAAm ranged from 1.60 to 4.04 within 15 h of reaction, which was attributed to the collapse of the PNIPAAm chains at temperature above the LCST that causes a decrease of the polymer reactivity. This was also attributed to the star–star coupling that generates twice the value of the polydispersity for any time before 15 h of polymerization.     

Polyphenolic glycosides and aglycones utilize opposing pathways to selectively remodel and inactivate toxic oligomers of amyloid β

Substantial evidence suggests that soluble prefibrillar oligomers of the Aβ42 peptide associated with Alzheimer's disease are the most cytotoxic aggregated Aβ isoform. Limited previous work has revealed that aromatic compounds capable of remodeling Aβ oligomers into nontoxic conformers typically do so by converting them into off-pathway aggregates instead of dissociating them into monomers. Towards identifying small-molecule antagonists capable of selectively dissociating toxic Aβ oligomers into soluble peptide at substoichiometric concentrations, we have investigated the pathways used by polyphenol aglycones and their glycosides to remodel Aβ soluble oligomers. We find that eleven polyphenol aglycones of variable size and structure utilize the same remodeling pathway whereby Aβ oligomers are rapidly converted into large, off-pathway aggregates. Strikingly, we find that glycosides of these polyphenols all utilize a distinct remodeling pathway in which Aβ oligomers are rapidly dissociated into soluble, disaggregated peptide. This disaggregation activity is a synergistic combination of the aglycone and glycone moieties because combinations of polyphenols and sugars fail to disaggregate Aβ oligomers. We also find that polyphenolic glycosides and aglycones use the same opposing pathways to remodel Aβ fibrils. Importantly, both classes of polyphenols fail to remodel nontoxic Aβ oligomers (which are indistinguishable in size and morphology to Aβ soluble oligomers) or promote aggregation of freshly disaggregated Aβ peptide; thus revealing that they are specific for remodeling toxic Aβ conformers. We expect that these and related small molecules will be powerful chemical probes for investigating the conformational and cellular underpinnings of Aβ-mediated toxicity.     

Electrocatalytic reduction of nitrite on tetraruthenated metalloporphyrins/Nafion glassy carbon modified electrode

This paper describes the electrochemical reduction of nitrite ion in neutral aqueous solution mediated by tetraruthenated metalloporphyrins (Co(II), Ni(II) and Zn(II)) electrostatically assembled onto a Nafion film previously adsorbed on glassy carbon or ITO electrodes. Scanning electron microscope (SEM-EDX) and transmission electron microscopy (TEM) results have shown that on ITO electrodes the macrocycles forms multiple layers with a disordered stacking orientation over the Nafion film occupying hydrophobic and hydrophilic sites in the polyelectrolyte. Atomic force microscopy (AFM) results demonstrated that the Nafion film is 35 nm thick and tetraruthenated metalloporphyrins layers 190 nm thick presenting a thin but compacted morphology. Scanning electrochemical microscopy (SECM) images shows that the Co(II) tetraruthenated porphyrins/Nf/GC modified electrode is more electrochemically active than their Ni and Zn analogues.These modified electrodes are able to reduce nitrite at −660 mV showing enhanced reduction current and a decrease in the required overpotential compared to bare glassy carbon electrode. Controlled potential electrolysis experiments verify the production of ammonia, hydrazine and hydroxylamine at potentials where reduction of solvent is plausible demonstrating some selectivity toward the nitrite ion. Rotating disc electrode voltammetry shows that the factor that governs the kinetics of nitrite reduction is the charge propagation in the film.     

Brazilian external occupational dose management system

Brazil, a large country, with more than 120,000 workers under individual monitoring for ionising radiation, developed, more than 20 y ago, a centralised data bank for external occupational dose. This old database, however, presented some problems and does not satisfy any more Brazilian present needs, not allowing dose analysis reports, for example. Therefore, a new system that reduces manual tasks, provides system communication support, manages reports and improves data storage management is being developed. This paper describes this new web-based information system, named Brazilian External Occupational Dose Management database system--GDOSE.     

The effect of kefir addition on microstructure parameters and physical properties of porous white bread

The effect of kefir concentration on the quality of porous white bread has been investigated. Quality evaluation was done using flatbed scanning (FBS) for measuring crumb porosity, instrumental texture profile analysis (TPA), crust and crumb color (L ^* a ^* b ^*), moisture, specific volume, and density determination techniques. The correlations between porosity, brightness, and firmness were also investigated. Long fermentation time of the sourdough changed significantly (p<0.05) the cell mean area (mm²), cell mean perimeter (mm), firmness (N), chewiness (N), light reflectance, and specific volume (ml/g). A strong correlation was found between microstructure of porous white bread, brightness (L), and firmness from TPA test. Kefir prolonged the shelf life of bread.