Single-Phase MnFe2O4 Powders Obtained by the Polymerized Complex Method

The present investigation reports on a simple technique for the preparation of single-phase MnFe₂O₄ nanocrystalline powders using the polymerized complex method, starting from manganese carbonate and iron nitrate. A mixed aqueous solution with citric acid, ethylene glycol, Fe, and Mn ions was polymerized. The phases formation, the homogeneity, and the structure of the obtained powders have been investigated by thermogravimetry, X-ray diffraction (XRD), scanning and transmission electron microscopy, and Mössbauer spectroscopy measurements. The magnetic hysteresis loop behavior was measured at 5 K in a vibrating sample magnetometer. XRD results demonstrated that thermally induced crystallization of cubic MnFe₂O₄ from the Mn–Fe polymeric precursor occurred at temperatures as low as 400°C. Pure single-phase MnFe₂O₄ nanocrystallites without any impurity or amorphous phases were obtained when the precursor was treated at 600°C for 1 h.     

Chemoenzymatic Synthesis and Inhibitory Activities of Hyacinthacines A1 and A2 Stereoisomers

A novel straightforward chemoenzymatic procedure for the synthesis of hyacinthacine stereoisomers based on the aldol addition of dihydroxyacetone phosphate (DHAP) to N‐Cbz‐prolinal under catalysis by L ‐rhamnulose 1‐phosphate aldolase from E. coli is presented. The synthesis is complemented by a simple and effective purification protocol consisting of ion‐exchange chromatography on CM‐sepharose. As examples, (−)‐hyacinthacine A₂ [the enantiomer of (+)‐hyacinthacine A₂], 7‐deoxy‐2‐epialexine (the enantiomer of 3‐epihyacinthacine A₂), ent‐7‐deoxyalexine (the enantiomer of 7‐deoxyalexine) and 2‐epihyacinthacine A₂ were synthesized by these procedures and characterized for the first time. These new isomers were assayed as inhibitors of glycosidases. As a result, (−)‐hyacinthacine A₂ demonstrated to be a good inhibitor of α‐D ‐glucosidase from rice whereas the natural enantiomer, hyacinthacine A₂, was not. Moreover, a new family of inhibitors of α‐L ‐rhamnosidase was uncovered.     

Non-destructive estimation of moisture,water activity and NaCl at ham surface during resting and drying using NIR spectroscopy

This paper describes the ability of near infra-red reflectance (NIR) spectroscopy to predict moisture, water activity (a_w) and NaCl content at the surface of dry-cured ham during the process. A Fourier Transform (FT) NIR spectrometer and two probes (on-contact and remote) were tested directly on the surface (gracilis muscle) of 98 hams during the process. The highest precision was achieved when two spectra per sample were used in the predictive model development. The models based on the remote measurement probe yielded acceptable results with determination coefficients (r²) of 0.93, 0.62 and 0.91 and residual predictive deviation (RPD) of 3.74, 1.63 and 3.33 for moisture, a_w and NaCl content, respectively. These results show that NIR measurements could be included in the control system of the resting and drying processes to prevent crusting in dry-cured ham.     

Performance of carbon-supported PtPd as catalyst for hydrogen oxidation in the anodes of proton exchange membrane fuel cells

In this work, the replacement of platinum by palladium in carbon-supported catalysts as anodes for hydrogen oxidation reaction (HOR), in proton exchange membrane fuel cells (PEMFCs), has been studied. Anodes with carbon-supported Pt, Pd, and equiatomic Pt:Pd, with various Nafion^® contents, were prepared and tested in H₂|O₂ (air) PEMFCs fed with pure or CO-contaminated hydrogen. An electrochemical study of the prepared anodes has been carried out in situ, in membrane electrode assemblies, by cyclic voltammetry and CO electrooxidation voltammetry. The analyses of the corresponding voltammograms indicate that the anode composition influences the cell performance. Single cell experiments have shown that platinum could be replaced, at least partially, saving cost with still good performance, by palladium in the hydrogen diffusion anodes of PEMFCs. The performance of the PtPd catalyst fed with CO-contaminated H₂ used in this work is comparable to Pt, thus justifying further work varying the CO concentration in the H₂ fuel to assert its CO tolerance and to study the effect of the Pt:Pd atomic ratio.     

WeMOI and NAOi influence on major avalanche activity in the Eastern Pyrenees

Major avalanche episodes registered in the Eastern Pyrenees (north-eastern Iberian Peninsula) are correlated with both the North Atlantic Oscillation (NAO) and the Western Mediterranean Oscillation (WeMO). The NAO is one of the most important and recurrent patterns of atmospheric circulation variability in the Northern Hemisphere and affects the behaviour of surface temperatures and precipitation in Western Europe. The Western Mediterranean Oscillation index (WeMOi) controls intense precipitation in the eastern part of the Iberian Peninsula. The link between both indices and major avalanche activity is undertaken by applying a cumulative index. A link between avalanche activity and the NAO has been found in Iceland, but it has not been detected in areas closer to the Pyrenees, such as the French Alps. This paper examines the linkage to the NAO in an area further from the centres of the dipole than is the case for Iceland. Results show a significant negative correlation between major avalanche activity in the Eastern Pyrenees and both NAO index (NAOi) and WeMOi, which is even higher with the cumulative NAOi (CNI) and the cumulative WeMOi (CWI). The cumulative index reflects the cumulative effect of snow accumulation in the avalanche starting zones as precipitation is affected by the variations of NAOi and WeMOi. Consequently, the correlation is negative since it has been demonstrated that increased precipitation in the Eastern Pyrenees is linked to negative values of both low frequency patterns. Nevertheless, results from the diverse avalanche forecasting regions in the Eastern Pyrenees suggest a different response of avalanche activity to both indices, confirming the Pyrenees as a complex snow-climate boundary. Lastly, possible changes in avalanche activity in the coming decades may be suggested by the NAO evolution associated with global warming scenarios that are foreseen and the present interannual trend of the WeMOi.     

Synthesis and properties of poly(hexamethylene terephthalate)/multiwall carbon nanotubes nanocomposites

Poly(hexamethylene terephthalate) (PHT)/carbon nanotubes (CNT) nanocomposites containing 1% and 3% (w/w) of filler were prepared by two procedures: in situ ring-opening polymerization of hexamethylene terephthalate cyclic oligomers in the presence of CNT and melt blending of PHT/CNT mixtures. Arc discharge multiwalled carbon nanotubes, both pristine (MWCNT) and hydroxyl functionalized (MWCNT-OH), were used. The objective was to evaluate the effect of preparation procedure, nanotube side-wall functionalization and amount of nanotube loaded on properties of PHT. All nanocomposites showed an efficient distribution of the carbon nanotubes within the PHT matrix but interfacial adhesion and reinforcement effect was dependent on both functionalization and nanotubes loading. Significant differences in thermal stability and mechanical properties ascribable to functionalization and processing were observed among the prepared nanocomposites. All the prepared nanocomposites showed enhanced crystallizability due to CNT nucleating effects although changes in melting and glass transition temperatures were not significant.     

Process and recyclability analyses of innovative bio‐composite for tray

The originality of the present study is to give complete and pragmatic information associated with the preparation of a totally bio‐based composite. It covers the most relevant investigations from analyses of the fibres used as reinforcing elements to the final product acquisition and its recyclability analyses. This study is destined for packaging areas. It demonstrates the three‐dimensional formation processes with these new kinds of bio‐composites, as well as the recyclable features related to the prepared materials. Thus, several processing parameters were studied and a final tray was prepared. The addition of the fibres gives rise to an increase of the tray stiffness, when a flexible biopolymer is used as a matrix. The prepared bio‐composites were recycled several times (10 recycling cycles) and found that they maintain their most relevant characteristics. Thus, such bio‐composites can be reused several times. All these data, including a prototype sample prepared as a demonstrator, support the innovative and sustainable character of the packaging materials described. Copyright © 2010 John Wiley & Sons, Ltd.     

Mesh repair with user-friendly topology control

Limitations of current 3D acquisition technology often lead to polygonal meshes exhibiting a number of geometrical and topological defects which prevent them from widespread use. In this paper we present a new method for model repair which takes as input an arbitrary polygonal mesh and outputs a valid 2-manifold triangle mesh. Unlike previous work, our method allows users to quickly identify areas with potential topological errors and to choose how to fix them in a user-friendly manner. Key steps of our algorithm include the conversion of the input model into a set of voxels, the use of morphological operators to allow the user to modify the topology of the discrete model, and the conversion of the corrected voxel set back into a 2-manifold triangle mesh. Our experiments demonstrate that the proposed algorithm is suitable for repairing meshes of a large class of shapes.     

High Concentrations of Genistein Decrease Cell Viability Depending on Oxidative Stress and Inflammation in Colon Cancer Cell Lines

Genistein could play a crucial role in modulating three closely linked physiological processes altered during cancer: oxidative stress, mitochondrial biogenesis, and inflammation. However, genistein’s role in colorectal cancer remains unclear. We aimed to determine genistein’s effects in two colon cancer cells: HT29 and SW620, primary and metastatic cancer cells, respectively. After genistein treatment for 48 h, cell viability and hydrogen peroxide (H₂O₂) production were studied. The cell cycle was studied by flow cytometry, mRNA and protein levels were analyzed by RT-qPCR and Western blot, respectively, and finally, cytoskeleton remodeling and NF-κB translocation were determined by confocal microscopy. Genistein 100 µM decreased cell viability and produced G₂/M arrest, increased H₂O₂, and produced filopodia in SW620 cells. In HT29 cells, genistein produced an increase of cell death, H₂O₂ production, and in the number of stress fibers. In HT29 cells, mitochondrial biogenesis was increased, however, in SW620 cells, it was decreased. Finally, the expression of inflammation-related genes increased in both cell lines, being greater in SW620 cells, where NF-κB translocation to the nucleus was higher. These results indicate that high concentrations of genistein could increase oxidative stress and inflammation in colon cancer cells and, ultimately, decrease cell viability.