Lipid Damage Inhibition in Hake by Active Packaging Film with Natural Antioxidants

The capacity of the natural antioxidant to retard oxidation of polyunsaturated fatty acids in hake (Merluccius merluccius) muscle was investigated. Hake fillets were packaged in low‐density polyethylene with the natural antioxidant (sample C1 = 7 mg/dm² film and sample C2 = 24 mg/dm² film) or without the antioxidant (control sample) and frozen for 12 months at ?20°C. The results confirm the efficacy of an active packaging with a natural antioxidant derived from barley husks to slow the progress of lipid hydrolysis and increase oxidative stability in hake muscle. Determination of peroxide value, conjugated dienes, free fatty acids, thiobarbituric acid reactive substances (TBARS) and anisidine value (AV) proved suitable for studying lipid hydrolysis and primary and secondary lipid oxidation over time. After 6 months of frozen storage, the TBARS levels were lower in hake packed with low‐density polyethylene with the natural antioxidant (C1 and C2) than in the control sample; at month 12, the TBARS values of C1 and C2 were lower (16 and 21%, respectively) than the control samples. AVs observed in samples C1 and C2 at month 9 were lower than those observed in the control sample at month 12. Copyright © 2011 John Wiley & Sons, Ltd.     

Quality of service for voice over IP in networks with congestion avoidance

This paper assesses the impact of active queue management schemes on the quality of service of voice over Internet protocol applications. A new analytical method based on a fixed point approach to estimate the end-user satisfaction is proposed. The results obtained were validated using discrete event simulation techniques. In all the studied cases, it was observed a great deal of agreement between the analytical results and the results obtained through simulation. The theoretical predictions, as well as the presented empirical evidences confirm, as demonstrated in previous works, that the use of active queue management offers better quality of service than the traditional queue control mechanisms used in Internet. From these results, we may reasonably conclude that the presented method can be used for network design in the presence of voice traffic.     

Janus Magnetic‐Plasmonic Nanoparticles for Magnetically Guided and Thermally Activated Cancer Therapy

Progress of thermal tumor therapies and their translation into clinical practice are limited by insufficient nanoparticle concentration to release therapeutic heating at the tumor site after systemic administration. Herein, the use of Janus magneto‐plasmonic nanoparticles, made of gold nanostars and iron oxide nanospheres, as efficient therapeutic nanoheaters whose on‐site delivery can be improved by magnetic targeting, is proposed. Single and combined magneto‐ and photo‐thermal heating properties of Janus nanoparticles render them as compelling heating elements, depending on the nanoparticle dose, magnetic lobe size, and milieu conditions. In cancer cells, a much more effective effect is observed for photothermia compared to magnetic hyperthermia, while combination of the two modalities into a magneto‐photothermal treatment results in a synergistic cytotoxic effect in vitro. The high potential of the Janus nanoparticles for magnetic guiding confirms them to be excellent nanostructures for in vivo magnetically enhanced photothermal therapy, leading to efficient tumor growth inhibition.     

Synthesis and Thermal Behavior of Metallic Cobalt Micro and Nanostructures

Nano-Micro Letters - In this contribution, a comparative study of metallic cobalt micro and nanoparticles obtained in solution by four different chemical routes is reported. Classic routes such as...     

Boosting the photocatalytic hydrogen production of TiO2 by using copper hexacyanocobaltate as co-catalyst

The development of cheap and efficient co-catalysts is crucial to improve the performance of well-known photocatalysts towards the hydrogen evolution reaction. Here, copper hexacyanocobaltate was evaluated for the first time as a potential candidate to be used as co-catalyst coupled with conventional TiO₂. Copper hexacyanocobaltate was formed by chemical precipitation in the presence of TiO₂, without needing further treatments. The composite exhibited paramount performance towards hydrogen generation, surpassing by up to 16 times the behavior reached with bare TiO₂. This composite also overcome the performance of conventional TiO₂ modified with copper and cobalt oxides derived from copper hexacyanocobaltate. The enhanced behavior of TiO₂/Cu₃[Co(CN)₆]₂ composite was promoted by the efficient separation of photogenerated charge carries, and the faster charge transfer from photocatalyst towards species in solution, as it was proved by the photoelectrochemical characterization of the materials. Furthermore, the composite experienced a slight detriment (15%) in its hydrogen production rate after four consecutive photocatalyst tests. This variation was attributed to the slow leaching of copper in the co-catalyst caused by its partial transformation into metal hydroxides, as it was suggested by the ex-situ XPS characterization. Nevertheless, the structural characterization evinced the presence of the Cu₃[Co(CN)₆]₂ in the composite after long-term use. This study should be considered a proof of concept on a reliable route to obtain appropriate composites for hydrogen production using light as primary energy source.     

Hepatectomy including more than half of liver volume with intermittent portal triad occlusion

The main results of the bloodstream infection (BSI) component of the Belgian National Programme for the Surveillance of Hospital Infections (NSIH project) are reported. From October 1992 to September 1996, 117 hospitals (59.1% of Belgian acute-care institutions) reported 13678 nosocomial BSIs. The incidence was 7.05 BSI episodes per 10000 patient-days. The incidence of BSI increased with hospital size and over time. Bloodstream infections were secondary to an infectious body site in 40.3% of the episodes, catheter-related in 23.5%, and of unknown origin in 36.2%. The associated in-hospital mortality was 31.4% and was highest in BSIs secondary to a respiratory tract infection (49.3%). In intensive care units, the incidence of BSI was 38.5 per 10000 patient-days. Coagulase-negative staphylococci were the most prevalent microorganisms (22%), followed by Staphylococcus aureus (14.1%) and Escherichia coli (13.5%). In catheter-related BSIs, these proportions were 41.9%, 18.8%, and 2.3%, respectively. The proportion of polymicrobial episodes was 9.9%. Methicillin resistance in Staphylococcus aureus was 22.3%. With its high participation rate, the NSIH project has characterized the epidemiology of nosocomial BSIs in Belgium during the period studied.     

Mixed valences system in cobalt iron cyanide. Microporous structure stability

Divalent transition metal hexacyanoferrates(III) have a microporous framework appropriate for separation and storage of small molecules. The nature of such porous framework is found in the existence of systematic vacancies of the building unit, the hexacyanoferrate octahedral block, [Fe(CN)₆], in the material structure. The relatively low thermal stability appears to be the main limitation of these materials for such applications. In the as-synthesized material the available free volume is occupied by water which, can be removed by moderated heating but always involving decomposition of at least a small sample fraction. For cobalt a unique behavior has been observed. The heating of cobalt(2+) hexacyanoferrate(III) leads to an inner charge transfer to form the mixed valences Co(2+)Co(III) hexacyanoferrate(II,III) system. Since this inner oxidation–reduction reaction does not modify the coordination environments for the involved metals, the porous nature of the parent compound could be preserved and at the same time with a higher thermal stability related to the formation of the most stable ferrous species. The porous structure of the obtained material was evaluated from CO₂ adsorption, X-ray diffraction, thermo-gravimetric, and infrared and Mössbauer spectroscopic data. The heat-induced charge transfer is accompanied of a progressive fracture of the material crystallites and also of a decrease for the pore volume as detected by the CO₂ adsorption. For comparative purposes, a parallel study on a porous Prussian blue (ferric hexacyanoferrate(II)) species was carried out. The porous framework of this last material is also related to systematic vacancies of the hexacyanoferrate building block but without the mentioned heat-induced charge transfer effect. In this case the sample heating has no effect on the material porous properties.