Signing avatars: making education more inclusive

Universal Access in the Information Society - In Brazil, there are approximately 9.7 million inhabitants who are deaf or hard of hearing. Moreover, about 30% of the Brazilian deaf community is...     

Control of size in losartan/copper(II) coordination complex hydrophobic precipitate

Reaction of highly soluble orally active, non-peptide antihypertensive drug losartan with copper(II) leads to the spontaneous formation of a very insoluble 2:1 covalent complex, which self assembles in a hydrophobic supramolecular structure of nanometric dimensions. Thermal analysis showed that Los/Cu(II) complex presents intermediate stability in comparison with its precursors KLos and Cu(OAc)₂·H₂O. Isothermal titration calorimetry indicated complexation to be a stepwise process, driven by enthalpy and entropy. Zeta potential and DLS measurements showed that it is possible to control the size and charge of nanoprecipitates by adjusting the relative concentration of Los^? and Cu(II).     

Cold‐set whey protein gels induced by calcium or sodium salt addition

Cold‐set whey protein isolate (WPI) gels formed by sodium or calcium chloride diffusion through dialysis membranes were evaluated by mechanical properties, water‐holding capacity and microscopy. The increase of WPI concentration led to a decrease of porosity of the gels and to an increase of hardness, elasticity and water‐holding capacity for both systems (CaCl₂ and NaCl). WPI gels formed by calcium chloride addition were harder, more elastic and opaque, but less deformable and with decreased ability to hold water in relation to sodium gels. The non linear part of stress–strain data was evaluated by the Blatz, Sharda, and Tschoegl equation and cold‐set gels induced by calcium and sodium chloride addition showed strain‐weakening and strain‐hardening behaviour, respectively. The fractal structure of the gels indicated a weak‐link behaviour. For WPI gels results suggest intrafloc links, formed at heating step, which were more rigid than the interfloc links, promoted by salt addition.     

Heat‐induced gels of soy protein and κ‐carrageenan at different pH values

Heat‐induced (90 °C/30 min) gelling of soy protein isolate (SPI) and κ‐carrageenan (κ‐CR) systems at pH values of 6.7 and 5.7 was evaluated. κ‐CR addition, increase in protein concentration and reduction in pH led to decreases in the initial gel structure forming temperature. Self‐supporting gels were not formed at concentrations of 8% (w/w) SPI or at concentrations below 0.3% (w/w) κ‐CR, but an increase in the concentration of SPI and κ‐CR led to an increase in the stress at rupture without influencing the deformability. Gel properties were a consequence of a simultaneous process of gelling and phase separation during heating. The non‐linear parameter of the Blatz, Sharda and Tschoegl (BST) rheological model allowed for the evaluation of the structural characteristics that in general corresponded to strain hardening behaviour. Strain weakening behaviour was observed at high biopolymer concentrations and at pH 6.7, which was associated with accentuated phase separation and a more discontinuous gel network.     

Discontinuous maps exhibiting symmetry Lebesgue-almost everywhere

In this paper we analyse the existence of a certain type of symmetry in the context of discontinuous maps. The classical notions of symmetry cannot be applied due to the existence of discontinuities and a broader version using a measure-theory perspective is introduced. We show that a group structure is also present under the new type of symmetry and derive results which are analogous in nature to results in the theory of continuous maps. Our motivation stems from examples of symmetric patterns arising in simulations with the Goetz map.     

Evaluating sources of PAHs in urban streams based on land use and biomonitors

Toxic polycyclic aromatic hydrocarbons (PAHs) can be found in wastewaters and sewages released from industries and/or urban areas. When discharged untreated to stream waters, they can be a problem to human health. This work represents the first attempt to use PAH and metal concentrations in aquatic moss transplants together with land-use information to identify water pollution sources in urban areas. To do this, the moss Fontinalis antipyretica was collected from a natural stream and transplanted to four different streams in a densely populated area of Lisbon, Portugal. After three months of exposure, mosses were collected and analyzed for metals and for the 16 priority PAHs recommended by the U.S. EPA. Urban streams seem to have a scattered contamination of 6-ring PAHs. Correlations among land-use, metal concentrations, and PAH concentrations indicated that areas occupied by activities of tertiary and industrial sectors had higher PAH concentrations in transplanted mosses, mainly for the sum of the 16 EPA-PAHs and for the 2-, 3- and 5-ringed PAHs, than areas occupied by urban and wooded areas. These PAHs were associated with enhanced Zn and Cu and land use activities that linked the sites to high traffic density. Industrial land use influences PAH concentration in water up to 1000 m of distance from the stream, whereas tertiary sector land use influences it up to 500 m.     

Predicting the drying kinetics of salted codfish (Gadus Morhua): semi‐empirical,diffusive and neural network models

This work aims to compare the accuracy of several drying modelling techniques namely semi‐empirical, diffusive and artificial neural network (ANN) models as applied to salted codfish (Gadus Morhua). To this end, sets of experimental data were collected to adjust parameters for the models. Modelling of codfish drying was performed by resorting to Page and Thompson semi‐empirical models and to a Fick diffusion law. The ANN employed a neural network multilayer ‘feed‐forward’, consisting of one input layer, with four neurons, one hidden layer, formed by five neurons and one output layer with a convergence criterion for training purposes. The simulations showed good results for the ANN (correlation coefficient between 0.987 and 0.999) and semi‐empirical models (correlation coefficient ranging from 0.992 to 0.997 for Page’s model, and from 0.993 to 0.996 for Thompson’s model), while improvements were required to obtain better predictions by the diffusion model (correlation coefficients ranged from 0.864 to 0.959).