Recovering spectral data from natural scenes with an RGB digital camera and colored filters

Many spectral‐recovery methods using RGB digital cameras assume the underlying smoothness of illuminant and reflectance spectra, and apply low‐dimensional linear models. The aim of the present work was to test whether a direct‐mapping method could be used instead of a linear‐models approach to recover spectral radiances and reflectances from natural scenes with an RGB digital camera and colored filters. In computer simulations, a conventional RGB digital camera with up to three colored filters was used to image scenes drawn from a hyperspectral image database. Three measures were used to evaluate recovery with the direct‐mapping method: goodness‐of‐fit, root‐mean‐square error, and a color‐difference metric. It was found that with two and three filters both spectral radiances and reflectances could be recovered sufficiently accurately for many practical applications. With little increase in computational complexity, an RGB camera and a few colored filters can provide significantly better recovery of natural scenes than an RGB camera alone. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 352–360, 2007     

Computational color analysis of paintings for different artists of the XVI and XVII centuries

We have performed a computational color analysis of images of paintings for six master painters: Titian, Rubens, El Greco, Velázquez, Rembrandt, and Vermeer. These painters show the evolution from the renaissance to the baroque style. Different first and second‐order statistical parameters have been obtained and analyzed in order to fix which of them can be common for the different artists and which of them can be representative of a certain period of time or the evolution of the art. The firsts include the orientation and semi‐axes ratio of the ellipses that define the gamut in the chromaticity diagram and the dependencies with the frequency of the power of the Fourier transforms. Most differences among artists can be found in the volume and area of the gamut, the number of discernible colors which is greater for Titian, El Greco and Rubens, compared to Velázquez, Rembrandt and Vermeer, the average value of L* and the number of dark pixels.     

PS/PMMA-CdSe/ZnS Quantum Dots Hybrid Nanofibers for VOCs Sensors

Hybrid nanofibers containing CdSe/ZnS quantum dots have been produced by electrospinning of hybrid latexes to characterize the electro-optical behavior of this novel luminescent sensing material. The latexes are synthesized by seeded semi-batch emulsion polymerization yielding cross-linked core-shell PS/QDs/PMMA particles with efficiently encapsulated quantum dots guaranteeing a good optical stability. Addition of polyvinyl alcohol (PVA) or polyethylene oxide (PEO) to the latexes is necessary to produce polymeric dispersions suitable for electrospinning manufacture of the nanometric fibers. The optimized polymeric dispersions are successfully electrospun obtaining fluorescent nanofibers in both cases. The hybrid nanofibers are sensitive to selected solvents (acetone, methanol and THF) and present positive response making them good candidates for the production of VOC sensors.     

Anti-Trypanosoma cruzi Activity of Metabolism Modifier Compounds

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and affects over 6 million people worldwide. Development of new drugs to treat this disease remains a priority since those currently available have variable efficacy and frequent adverse effects, especially during the long regimens required for treating the chronic stage of the disease. T. cruzi modulates the host cell-metabolism to accommodate the cell cytosol into a favorable growth environment and acquire nutrients for its multiplication. In this study we evaluated the specific anti-T. cruzi activity of nine bio-energetic modulator compounds. Notably, we identified that 17-DMAG, which targets the ATP-binding site of heat shock protein 90 (Hsp90), has a very high (sub-micromolar range) selective inhibition of the parasite growth. This inhibitory effect was also highly potent (IC₅₀ = 0.27 μmol L⁻¹) against the amastigote intracellular replicative stage of the parasite. Moreover, molecular docking results suggest that 17-DMAG may bind T. cruzi Hsp90 homologue Hsp83 with good affinity. Evaluation in a mouse model of chronic T. cruzi infection did not show parasite growth inhibition, highlighting the difficulties encountered when going from in vitro assays onto preclinical drug developmental stages.     

The effect of blanching on the quality of dehydrated broccoli florets

Different blanching treatments were applied to broccoli florets prior to dehydration in order to improve product quality. The pretreatments used were a conventional blanching in water at 99ǃ °C, and a stepwise blanching (a blanching at low temperature followed by a short blanching at high temperature after a holding time) using different temperatures for the first step (50, 55, 60, 65 and 70 °C). Five rehydration temperatures were used (25, 40, 55, 65 and 80 °C). Rehydration rate (D_eff and W_e), chlorophyll content and texture of the rehydrated product were evaluated. Rehydration was modelled according to Fick's diffusion equation. A good agreement between the model and the experimental data was obtained when D_eff and W_e values were identified for each temperature (average explained variance 96.9%). Samples stepwise blanched at 60 °C showed, on the average, the lowest W_e values. Stepwise blanching at 60-65 °C and rehydration at 25-55 °C were the combinations that gave the firmest product. Stepwise blanching at 50 °C together with the conventional blanching (99ǃ °C) and rehydration between 25 and 65 °C were the combinations that allowed preservation of the highest chlorophyll content. From these results, it seems difficult to obtain firm samples with a high chlorophyll content without additives.     

Presence of furosine in honeys

Nineteen commercial samples (with a shelf‐life of 2 years) and two artisanal samples (freshly collected and stored for 1 year respectively) of Spanish honeys were analysed for pH, protein content and furosine content. Most of the samples had pH values and protein contents within the limits reported in the literature. The presence of furosine was confirmed by comparison of its retention time with that of a furosine standard and by HPLC–MS. The level of furosine in the samples studied ranged from 4.32 to 13.62 g kg^?1 protein. The lowest furosine value was observed in the freshly collected artisanal sample. Heat treatment under severe conditions (90 °C for up to 135 min) increased the furosine content from 4.43 to 14.38 g kg^?1 protein. The results show that furosine seems to be a promising indicator to detect overheating during honey manufacture. © 2001 Society of Chemical Industry     

The design of a Virtual Library of Emblem Books

Antique documents, which undoubtedly represent our cultural heritage and can be considered a very rich source of information, are kept in many countries only on libraries with historical archives. The antiquity and fragility of such documents makes their access very restricted. Considering that nowadays the Internet is one of the most interesting places to publish any kind of information, it seems logical to use it to both preserve our cultural heritage and provide a broader access to these documents. This work presents a virtual library that stores data, transcribed texts and digitalized pages of historic Spanish documents from the 16th–18th centuries. This virtual library has two main objectives: first, by offering a set of services, including a powerful user interface to search and browse the documents, a bulletin board, a chat, or mail boxes, the virtual library is transformed into a meeting place for researchers that use emblem books as sources of information for their studies. Second, the virtual library contributes to the preservation of emblem books. We shall describe in this work the project that led to the development of the Virtual Library of Emblem Books, showing its evolution from the beginning (simple search forms and answer pages) to its current state as a virtual library, focusing on the techniques used to build an intuitive and powerful user interface. Copyright © 2006 John Wiley & Sons, Ltd.     

Dual holographic interferometry for measuring the three velocity components in a fluid plane

A technique that allows one to measure simultaneously the three velocity components in a fluid plane is presented. One obtains the quantitative information from only one holographic recording by combining two different reconstruction processes. As both processes use an interferometric comparison of two waves, we refer to this technique as dual holographic interferometry. The far-field fringe pattern that is obtained when reconstruction is made with an expanded laser beam allows one to determine the in-plane velocity components. The image-field fringe pattern that is obtained when a pointwise laser beam is used for reconstruction contains information about an out-of-plane velocity component. As the two reconstruction processes have different sensitivities, two different ways to combine them are proposed. The system has been demonstrated in a fluidlike solid object and in a convective flow.     

A contribution to the kinetics of the polymerization of styrene with CF3SO3H as catalyst

Summary The time dependence of the cationic polymerization of styrene in CH₂Cl₂ with CF₃SO₃H as catalyst can be formally described as being first-order with respect to monomer concentration [M]₀. The reaction rate shows a third-order dependence in catalyst concentration [C]₀. A high polymer and a low polymer polystyrene fraction are found at [M]₀>0.2 mole · l^–. The reaction rate of the high polymer fraction is proportional to [C] ₀ ³ , that of the low polymer fraction probably proportional to [C] ₀ ² . The polymerization active species may thus be triple ions in the first and ion pairs in the second case.