The influence of carbon particle type in fly ashes on mercury adsorption

Recent research has shown that certain fly ash materials produced in coal combustion for power generation have an affinity for the mercury compounds present in flue gases. However, the exact nature of Hg-fly ash interactions is still unknown and the different variables that influence mercury adsorption need to be identified. In this work the microscopic components of fly ashes derived from the combustion of different types of feed blends of different coal rank and mercury adsorption were investigated. The aim of this research was to establish relationships between Hg retention and the type of unburned carbons present in various fly ashes. The fly ashes and fly ash fractions studied were used as sorbent beds for high mercury concentrations, conditions in which mercury retention is highly favored. From the results obtained it was confirmed that the role of the unburned carbon components in mercury capture may depend, among other factors, on the type of unburned carbon. Fly ashes capture different species of mercury depending on their nature and the type of anisotropic particles.     

Influence of the Addition of a Second Metal on the Catalytic Performance of Pt-Beta Agglomerated Catalyst in the Hydroisomerization of n-Octane

In this work, the hydroisomerization of n-octane on mono and bimetallic beta agglomerated zeolite based catalysts was investigated. As the metal function, platinum and combinations with nickel and tin were studied. Test reactions were carried out at 10 bar and 290–410 °C. The bimetallic catalyst with the lowest amount of Ni yielded the greatest multibranched selectivity.     

Highly selective transport of transesterification reaction compounds through supported liquid membranes containing ionic liquids based on the tetrafluoroborate anion

We previously reported the selective simultaneous separation of the substrates and products of a transesterification reaction (vinyl butyrate, 1-butanol, butyl butyrate and butyric acid) through supported liquid membranes (SLMs) based on 1-n-alkyl-3-methylimidazolium cations combined with tetrafluoroborate, hexafluorophosphate and bis{(trifluoromethyl)sulfonyl}imide anions. The best results were obtained by the use of tetrafluoroborate based ionic liquids, which led us to further investigate the use of these new supported liquid membranes for the selective separation of different substrates and products of transesterification reactions. With this aim, the permeability of sixteen different organic compounds (vinyl esters, aliphatic esters, alcohols and carboxylic acids) through SLMs containing tetrafluoroborate based ionic liquids ([bmim⁺][BF₄⁻] and [omim⁺][BF₄⁻]) were evaluated. It was found that permeability increased as the alkyl chain length decreased for the same organic functional group. In addition, significant permeability differences were found between the different organic functional groups.As regards the operational stability of these SLMs, they were seen to be very stable when tested over eight continuous cycles of 48 h each.     

Bioinformatic Tools for the Analysis and Prediction of ncRNA Interactions

Noncoding RNAs (ncRNAs) play prominent roles in the regulation of gene expression via their interactions with other biological molecules such as proteins and nucleic acids. Although much of our knowledge about how these ncRNAs operate in different biological processes has been obtained from experimental findings, computational biology can also clearly substantially boost this knowledge by suggesting possible novel interactions of these ncRNAs with other molecules. Computational predictions are thus used as an alternative source of new insights through a process of mutual enrichment because the information obtained through experiments continuously feeds through into computational methods. The results of these predictions in turn shed light on possible interactions that are subsequently validated experimentally. This review describes the latest advances in databases, bioinformatic tools, and new in silico strategies that allow the establishment or prediction of biological interactions of ncRNAs, particularly miRNAs and lncRNAs. The ncRNA species described in this work have a special emphasis on those found in humans, but information on ncRNA of other species is also included.     

Evaluation of direct light processing for the fabrication of bioactive ceramic scaffolds: Effect of pore/strut size on manufacturability and mechanical performance

Bioactive ceramic scaffolds for bone regeneration consisting of a three-dimensional mesh of interpenetrating struts with square section were fabricated via Digital Light Processing (DLP). The ability of the technique to manufacture 3D porous structures from β-tricalcium phosphate (β-TCP) powders with different dimensions of struts and pores was evaluated, identifying the possibilities and limitations of the manufacturing process. Small pore sizes were found to seriously complicate the elimination of excess slurry from the scaffold’s innermost pores. The effect of the strut/pore size on the mechanical performance of the scaffolds under compressive stresses was also evaluated, but no significant influence was found. Under compressive stresses, the structures resulted weaker when tested perpendicularly to the printing plane due to interlayer shear failure. Interlayer superficial grooves are proposed as potential failure-controlling defects, which could also explain the lack of a Weibull size effect on the mechanical strength of the fabricated DLP scaffolds.     

Serum concentrations of polyfluoroalkyl compounds in Faroese whale meat consumers

To learn the extent of human exposure to polyfluoroalkyl compounds (PFCs) in a remote fishing population, we measured, in Faroese children and pregnant women, the serum concentrations of nine PFCs, including perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorononanoate (PFNA), by using online solid-phase extraction coupled to isotope dilution high-performance liquid chromatography-tandem mass spectrometry. The serum samples analyzed had been collected between 1993 and 2005 from 103 children 7 years of age, 79 of these children at 14 years of age, and from 12 pregnant women and their children 5 years later. PFOS was detected in all samples analyzed, and both PFOA and PFNA were detected in all but one of the samples. The concentrations found are comparable tothose reported elsewhere. Correlations between paired concentrations were poor. However, PFOS and PFNA concentrations correlated well with the frequency of pilotwhale dinners and with concentrations of mercury and polychlorinated biphenyls. One whale meal every two weeks increased the PFOS concentration in 14-year-olds by about 25% and PFNA by 50%. The high frequency of detection of most PFCs suggests widespread exposure in the Faroe Islands already by the early 1990s, with whale meat being an important source.     

Improving the control of food production in catering establishments with particular reference to the safety of salads

Food production in four school kitchens was checked in order to improve food safety by establishing a self-regulated control system based on good manufacturing practices (GMPs) and as an introduction to hazard analysis and critical control points (HACCP). A form, which referred to different aspects such as the cleanliness of the installations, personnel hygiene and the prevention of cross-contamination, was used to obtain the necessary data. Furthermore, foods thought to be of high risk were periodically collected for microbiological analysis. Samples for microbiological examination were taken from cutting boards, tables, machines, knives and ingredients (on-line sampling). We used the results as a basis to train foodhandlers to improve the safety of salad preparation, in accordance with GMPs, observing that hygiene improvement depended on chlorine levels in the rinsing water. We also designed several controls for raw materials, cold storage, freezers and available chlorine levels in water. At the end of the study period, we observed a decrease in microbial populations of examined samples, which indicated that the knowledge of hygiene practices on the part of foodhandlers represents a critical control point, as defined by the EC Directive 93/43/EEC on Hygiene of Food Stuffs.     

The role of the consumer in the reduction of Listeria monocytogenes in lettuces by washing at home

Lettuce is highly appreciated for its nutritional properties; however microbial contamination through the food chain and its raw consumption may jeopardize these known benefits to the diet. The objective of this study was to determine the role of the consumer at the stage of washing at home, in relation to the probability of illness due to the presence of Listeria monocytogenes in lettuce. Survival curves of L. monocytogenes after washing (dipping with and without addition of bleach, and washing under a running tap) were studied. A mathematical model for each washing method was calculated by fitting experimental data. The obtained models were used to estimate the probability of illness after washing at home. Results show that although consumers can only deal with low loads of L. monocytogenes, their role is essential to reduce the normal contamination level of lettuces and ensure their safety.     

Preparation and characterization of Co-Ru/TiO2/MWCNTs electrocatalysts in PEM hydrogen electrolyzer

The subject of this study is preparation and characterization of hypo-hyper d-electrocatalysts with reduced amount of precious metals aimed for water electrolysis. The studied electrocatalysts contain 10% mixed metallic phase (Co:Ru = 1:1 wt., Co:Ru = 4:1 wt. and Co:Ru:Pt = 4:0.5:0.5 wt.), 18% TiO₂ as a crystalline anatase deposited on multiwalled carbon nanotubes (MWCNTs). Previously, MWCNTs were activated in 28% nitric acid. As a reference electrocatalyst for hydrogen evolution reaction, corresponding electrocatalysts with pure Pt metallic phase and mixed CoPt (Co:Pt = 1:1 wt.) metallic phase were prepared. Also, as a reference electrocatalyst for oxygen evolution reaction, electrocatalyst with pure Ru metallic phase was prepared.The prepared electrocatalysts were structurally characterized by means of XPS, XRD, TEM, SEM and FTIR analysis.Electrochemical characterization was performed by means of cyclic voltammetry and potentiodynamic method in the PEM hydrogen electrolyzer. The range of the catalytic activity for hydrogen evolution of studied electrocatalysts was the following: CoRuPt (4:0.5:0.5) > CoPt (1:1) > Pt > CoRu (1:1) > CoRu (4:1). The order of the catalytic activity for oxygen evolution was the following: CoRu (1:1) > Ru > CoRu (4:1) > Pt > CoRuPt (4:0.5:0.5) > CoPt (1:1).     

Evolution of biochemical and rheological characteristics and breadmaking quality during a multistage wheat sour dough process

Summary The evolution of some biochemical (acetic and lactic acid contents, fermentation quotient and changes in mono-, di-, and trisaccharides), rheological and fermentative characteristics (extensigram, maturogram and impulsogram) and bread quality (volume, density, texture, and degree of acidification) during a multistage wheat sour dough process have been investigated. Acetic acid contents of sour doughs (SD), bread doughs (BD) and breads (B) increased with the increase in number of processing stages. Lactic acid followed similar trends in SD, but in BD and B it reached maximum levels during the third stage. SD contained higher amounts of acids than BD and B. Dynamics of sugars followed patterns according to the fermentative activity and microflora evolution in the different steps. An improvement as the number of SD stages increased was observed in rheological and fermentative properties of BD, such as in oven spring. A positive effect on B characteristics (volume, density, texture, and acidity) was also observed. The last stage of the SD process led to the best final product, with noticable differences in relation to those occurring with a smaller number of stages.

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Entwicklung biochemischer und rheologischer Eigenschaften und des Backverhaltens während einer mehrstufigen Weizensauerteigführung

Zusammenfassung Es wurde die Entwicklung biochemischer Daten (Essigsäure- und Milchsäuregehalt, Gärungsquotient und Veränderungen an Mono-, Di- und Trisacchariden, rheologischer und Gäreigenschaften (Extensograph, Maturograph und Ofentrieb) und der Brotqualität (Volumen, Dichte, Textur und Säuregrad) während einer mehrstufigen Weizensauerteigführung untersucht. Die Essigsäuregehalte von Sauerteigen, Brotteigen und Broten stiegen mit der Zahl der Führungsstufen an. Beim Milchsäuregehalt ergaben sich ähnliche Tendenzen, jedoch beim Brotteig und Brot wurde das Maximum erst in der dritten Stufe erreicht. Veränderungen des Zuckergehaltes stimmten mit der Gäraktivität und der Mikrofloraentwicklung in den verschiedenen Stufen überein. Es ergab sich eine Verbesserung in den rheologischen und Gäreigenschaften von Brotteigen sowie im Ofentrieb, wenn die Zahl von Sauerteigstufen anstieg. Es wurde auch ein positiver Einfluß auf die Broteigenschaften (Volumen, Dichte und Säuregrad) beobachtet. Die letzte Stufe der Sauerteigführung ergab das beste Endprodukt mit deutlichen Unterschieden, wenn mit einer geringeren Zahl von Stufen hergestellt.

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Paper presented in part at the 7th World Congress of Food Science and Technology, Singapore (Singapore), September–October, 1987