Electronic properties of poly(thiophene-3-methyl acetate)

The electronic structure of poly(thiophene-3-methyl acetate) has been investigated using UV–vis absorption spectroscopy and quantum mechanical calculations. Experimental measures in chloroform solution indicate that the π-conjugation length increases with the polymer concentration, which is reflected by the red shift of the absorbance peak of the π-π* transition. On the other hand, the energy required for the π-π* transition has been found to decrease with the volatility of the solvent for concentrated polymer solutions, even though the influence of the solvent is very small for dilute solutions. Quantum mechanical calculations indicate that the interactions between the π-conjugated backbone and the methyl acetate side groups are very weak. On the other hand, the lowest energy transition predicted for an infinite polymer chain that adopts the anti-gauche and all-anti conformations is 2.8 and 1.9 eV, respectively. Finally, measurements on spin-casted nanofilms reflect that the π-π* transition energy increases with the thickness, which has been attributed to the distortion of the molecular conformation. In spite of this, the energy gap obtained for the thinnest film (1.52 eV) is significantly smaller than that determined for dilute and concentrated chloroform solutions (2.56 and 2.09 eV, respectively).     

Facile preparation of electrodes based on WO3 nanostructures modified with C and S used as anode materials for Li-ion batteries

An appropriate morphological and structure matrix configuration where lithium ions could insert and de-insert is essential for lithium-ion batteries (LiB). Tungsten oxides (WO₃) are especially attractive materials for this aim. In this research, the effects of the morphology and composition of WO₃ nanostructures on the charge/discharge behavior for Li-ion batteries are methodically examined. On the one hand, nanostructured WO₃ thin film was effectively synthesized by an electrochemical procedure. Then, an annealing treatment at 600°C in air environment for 4 h was carried out. In the second electrode synthesized, a carbon layer was uniformly deposited on WO₃ nanostructures to obtain a WO₃/C electrode. Finally, WO₃/WS₂ electrodes were prepared by means of in situ sulfurization of WO₃ one-step solid-state synthesis using tungsten trioxide (WO₃) and thiourea as precursor material. By using X-ray photoelectron spectroscopy, X-ray diffraction analysis, transmission electron microscopy, Raman spectra, and field-emission scanning electron microscopy, the three electrodes have been morphologically characterized. Electrochemical properties were analyzed by cyclic voltammogram, galvanostatic charge/discharge cycling, and electrochemical impedance spectroscopy. Among all the synthesized samples, WO₃/C nanostructures reveal the best performance as they exhibit the greatest discharge capacity and cycle performance (820 mA h g⁻¹).     

Methodology for heuristic evaluation of the accessibility of statistical charts for people with low vision and color vision deficiency

Universal Access in the Information Society - Statistical charts have an important role in conveying, clarifying and simplifying information and have a significant presence in fields such as...     

Pigment profile and colour of monovarietal virgin olive oils from Arbequina cultivar obtained during two consecutive crop seasons

Monovarietal virgin olive oils are labelled with the olive varieties giving them their distinctive character. There are numerous studies focussed on the characterisation and quantification of the minor fractions of virgin olive oils that have generated databases on varietal olive oils. However, few studies have focussed on the components of the pigment fraction of virgin olive oils. The aim of this work was to quantify the components of the chlorophyll and carotenoid fractions of the monovarietal virgin olive oils from the Arbequina cultivar, growing in the Spanish area of Catalonia, during two consecutive crop seasons. Additionally the pigment changes occurring during 24 months of oil storage were evaluated. The results of this study showed minor qualitative differences between monovarietal virgin olive oils from two consecutive seasons. The quantitative differences could be attributed to the harvest period in each season rather than to the year’s weather conditions. Storage of the monovarietal virgin olive oils probably caused an important loss of the chlorophyll fraction, mainly chlorophyll a, during the first 6 months of storage. On the other hand, the carotenoid fraction was very stable and the retention of provitamin A was close to 80%, even after 24 months of storage.     

Altitudinal gradients of PBDEs and PCBs in fish from European high mountain lakes

A first case of temperature-dependent distribution of polybromodiphenyl ethers (PBDEs) in remote areas is shown. Analysis of these compounds in fish from Pyrenean lakes distributed along an altitudinal transect shows higher concentrations at lower temperatures, as predicted in the global distillation model. Conversely, no temperature-dependent distribution is observed in a similar transect in the Tatra mountains (Central Europe) nor in fish from high mountain lakes distributed throughout Europe. The fish concentrations of polychlorobiphenyls (PCBs) examined for comparison showed significant temperature correlations in all these studied lakes. Cold trapping of both PCBs and PBDEs concerned the less volatile congeners. In the Pyrenean lake transect the concentrations of PCBs and PBDEs in fish were correlated despite the distinct use of these compounds and their 40 year time lag of emissions to the environment. Thus, temperature effects have overcome these anthropogenic differences constituting at present the main process determining their distributions. These cases of distinct PBDEs and PCBs behavior in high mountains likely reflect early stages in the environmental distribution of the former since they have been under secondary redistribution processes over much shorter time than the latter.     

Elucidating the Mechanism of Action of the Attributed Immunomodulatory Role of Eltrombopag in Primary Immune Thrombocytopenia: An In Silico Approach

Eltrombopag is a thrombopoietin receptor (MPL) agonist approved for the treatment of primary immune thrombocytopenia (ITP). Recent evidence shows that some patients may sustain platelet counts following eltrombopag discontinuation. The systemic immunomodulatory response that resolves ITP in some patients could result from an increase in platelet mass, caused either by the direct action of eltrombopag on megakaryocytes through MPL stimulation, or potential MPL-independent actions on other cell types. To uncover the possible mechanisms of action of eltrombopag, in silico analyses were performed, including a systems biology-based approach, a therapeutic performance mapping system, and structural analyses. Through manual curation of the available bibliography, 56 key proteins were identified and integrated into the ITP interactome analysis. Mathematical models (94.92% mean accuracy) were obtained to elucidate potential MPL-dependent pathways in non-megakaryocytic cell subtypes. In addition to the effects on megakaryocytes and platelet numbers, the results were consistent with MPL-mediated effects on other cells, which could involve interferon-gamma, transforming growth factor-beta, peroxisome proliferator-activated receptor-gamma, and forkhead box protein P3 pathways. Structural analyses indicated that effects on three apoptosis-related proteins (BCL2L1, BCL2, BAX) from the Bcl-2 family may be off-target effects of eltrombopag. In conclusion, this study proposes new hypotheses regarding the immunomodulatory functions of eltrombopag in patients with ITP.     

Selectivity and antimicrobial action of bovine lactoferrin derived peptides against wine lactic acid bacteria

In this study, the antibacterial activities of a bovine Lactoferrin pepsin hydrolysate (LFH) and a synthetic peptide derived from bovine lactoferricin (LfcinB_17–31) have been evaluated against Oenococcus oeni and three additional lactic acid bacteria (LAB) known to cause spoilage during winemaking processes. Inhibition of bacterial growth was demonstrated in vitro in synthetic broth media (MRS) for both LFH and LfcinB_17–31. The bactericidal activity of the synthetic peptide was also assayed and found to vary depending on the bacterial species and the matrix in which exposure to peptide occurred (either MRS broth or white must). Specificity of LfcinB_17–31 for Lactobacillus brevis, Pediococcus damnosus, and O. oeni was demonstrated in must fermentation experiments in which these three LAB co-existed with the winemaking Saccharomyces cerevisiae T73 in the presence of the peptide. Finally, fermentation experiments also showed that LfcinB_17–31 at inhibitory concentrations did not alter either fermentation kinetics or specific enological parameters.