Potentials on the hexagonal grid

The aim of this paper is to give an explicit computation for the potential generated by a dipole on a hexagonal grid. Such a computation will be expressed as the Fourier transform of a distribution on the bidimensional torus .     

Further Studies on Thermal Evolution of Glass-Forming Gels

Glasses of composition Na₂O·2SiO₂ containing iron oxide are obtained by the gel technique. The results show that the iron atoms accelerate the formation of the glass, whereas when they are present in low percentage (∼2%), the temperature necessary to obtain the glass phase is higher. During heat treatment at 250°C, two silicates are formed: Na₂SiO₃ and Na₄SiO₄. When the iron content is low, they change at 650°C into Na₂Si₂O₅, but when the iron content is higher (∼6%), this silicate does not form and the system becomes vitreous.     

Dependence of the electrical conductivity and elastomeric properties on sample preparation of blends of polyaniline and natural rubber

Blend films (free‐standing) containing 20% in volume of polyaniline (PANI) in 80% of natural rubber (NR) were fabricated by casting in three different ways: (1) adding PANI‐EB (emeraldine base) dissolved in N‐methyl‐2‐pyrrolidone (NMP) to the latex (NRL), (2) adding PANI‐EB dissolved in m‐cresol to NR dissolved in xylol (NRD), (3) overlaying the surface of a pure NR cast film with a PANI layer grown by in situ polymerization (NRO). All the films were immersed into HCl solution to achieve the primary doping (protonation) of PANI before the characterization. The main goal here was to investigate the elastomeric and electrical conductivity properties for each blend, which may be applied as pressure and deformation sensors in the future. The characterization was carried out by optical microscopy, dc conductivity, vibrational spectroscopy (infrared absorption and Raman scattering), thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and tensile stress–strain curves. The results suggest that the NRL blend is the most suitable in terms of mechanical and electrical properties required for applications in pressure and deformation sensors: a gain of conductivity without losing the elastomeric property of the rubber. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1498–1503, 2005     

Comparative study on the technological properties of latex and natural rubber from Hancornia speciosa Gomes and Hevea brasiliensis

This work reports a systematic comparative study of the technological properties of natural lattices and rubbers extracted from Hancornia speciosa Gomes and Hevea brasiliensis [(Willd. ex Adr. de Juss.) Muell.‐Arg.] (clone RRIM 600) trees from 11 collections in Brazil throughout 2004. Natural rubber latex particle sizes and distributions were quite similar with an average diameter around 1 μm. Molecular weight, Wallace plasticity, and Mooney viscosity values were approximately the same for both rubbers. Fourier transform infrared spectroscopy peaks characteristic of natural rubber were observed for both Hancornia and Hevea. The measured differences in technological properties included lower values for Hancornia dry rubber content, % ash, % nitrogen, and plasticity retention index but higher value for acetone extract. Interestingly, nitrogen and protein content were much lower in Hancornia, suggesting that it may have important applications in nonallergic rubber uses. This represents the first report of lacticifer‐produced low‐protein natural rubber. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Sociocognitive self-regulatory mechanisms governing transgressive behavior.

This longitudinal research examined a structural model of the self-regulatory mechanisms governing transgressive conduct. Perceived academic and self-regulatory efficacy concurrently and longitudinally deterred transgressiveness both directly and by fostering prosocialness and adherence to moral self-sanctions for harmful conduct. The impact of perceived social self-efficacy was mediated through prosocialness. Moral disengagement and prosocialness affected transgressiveness through the mediating influence of irascible affectivity and hostile rumination. Ruminative affectivity, in turn, both concurrently and longitudinally affected transgressiveness. Moral disengagement also contributed independently to variance in transgressiveness over time. This pattern of relations was obtained after controlling for prior transgressiveness. The structural model was replicated across gender and provided a better fit to the data than did several alternative models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of potential markers of primary fibromyalgia syndrome in human saliva

In the last few years, many attempts have been carried out for the research of specific biological biomarkers in fibromyalgia (FM) since, so far, no laboratory tests have been appropriately validated for the diagnosis and the prognostic stratification of the disease. In our study for the first time, we carried out a proteomic analysis of the whole saliva of FM patients in order to evaluate salivary biomarkers. Twenty-two FM patients with all fulfilling the American College of Rheumathology diagnostic criteria for FM and 26 sex-and age-matched healthy subjects were enrolled in the study. Proteomic analysis was performed by combining 2-DE and MALDI-TOF-MS. The most relevant observation which emerged from the data analysis was the exclusive and significant over-expression of transaldolase and phosphoglycerate mutase I. These findings were validated by Western blot analysis and the total optical density confirmed the significant up-regulation of transaldolase and phosphoglycerate mutase I in FM samples with respect to healthy subjects. It was noteworthy that seven further salivary proteins resulted differentially expressed, namely: calgranulin A, calgranulin C, cyclophilin A, profilin 1, Rho GDP-dissociation inhibitor 2, proteasome subunit-α-type-2 and haptoglobin-related protein precursor. These preliminary results demonstrated the utility of salivary proteomic analysis in the identification of salivary biomarkers in FM patients and in clarifying some of the pathogenetic aspects of the disease.     

Gender-related dissociations of categorical fluency in normal subjects and in subjects with Alzheimer's disease.

Semantic fluency tasks, with the categories of birds and furniture as stimuli, were administered to normal subjects and patients with Alzheimer's disease (AD). Normal subjects showed a gender-related double dissociation consistent with the literature data because men were more fluent with the birds category and women with the furniture category. Also, patients with AD showed a Gender × Category interaction, but the double dissociation between birds and furniture was not present because of a prevalent impairment of the living category birds that was irrespective of gender. This pattern of impairment in patients with AD was independent from the disease stage. The authors conclude that (a) gender-related categorical effects cannot be considered as inborn, sex-related cognitive differences but as familiarity effects and (b) both lesion-related and familiarity-related factors must be taken into account to explain category-specific effects of patients with brain damage and patients with AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Nonlinear Filtering Technique for the Identification of Biological Signals

A new nonlinear filtering technique is presented allowing extraction of relevant biological signals from background. The technique s derived from the one of dc restoration used in nuclear electronics. A discussion is given of the problem and a solution through the use of a nonlinear filter is proposed; the filter's way of operating is then described together with a complete multiunit neural spike processing instrument using this filtering technique. Some experimental results are presented.     

Application and Limitations of a Method Based on Pyrolysis Models to Simulate Railway Rolling Stock Fire Scenarios

This article relates the application of pyrolysis models to products used onboard trains, as part of a fire safety engineering design or assessment. It is based on work performed during the European Research program, TRANSFEU. As a first step in the methodology, risk analysis permits identification of the most critical scenarios to be studied, considering actual operational conditions and rules in the European railway network. The study of one such scenario has been performed using advanced numerical tools and a multi-scale approach from raw material to real scale, in order to validate the application of such techniques in fire risk assessment. Simulations have been compared to experimental data at each scale. This predictive method shows a good capability to properly reproduce fire growth, heat release rate, temperatures and carbon dioxide concentrations in a real-scale scenario. On the other hand, this study highlights poor prediction of concentrations of carbon monoxide and other toxic species.