Combination of electrophoretic deposition and microwave-ignited combustion synthesis for the preparation of ceramic coated intermetallic-based materials

Electrophoretic deposition (EPD) was used to deposit sub-micrometric ZrO₂ particles on metallic powder compacts belonging to the systems Ni + Al and Ti + Al, which were used as deposition electrodes in the EPD cell. After EPD, combustion synthesis (CS) of such reactive electrodes was ignited in a microwave single-mode applicator, operating at a frequency of 2.45 GHz, in order to obtain in a single step the synthesis of the desired intermetallic phase (substrate) and the sintering of the previously deposited ceramic particles (or coating). Experimental results demonstrate that the excess heat released during the formation of nickel and titanium aluminides by CS can be exploited not only to self-sustain and self-propagate the reaction front along the substrate, but also to rapidly sinter the coating obtained by EPD. The innovative procedure here proposed is a promising strategy in order to obtain, in a single step, high temperature intermetallic-based materials, protected by well adhered ceramic coatings.     

Anti-inflammatory activity of a new class of nitric oxide synthase inhibitors that release nitric oxide

Nitric oxide (NO) is a gaseous mediator that exerts key regulatory functions in mammalian cells. Low levels of NO exert homeostatic functions and counteract inflammation, whereas high amounts of NO cause tissue destruction and cellular death. Herein we describe a new class of nitric oxide synthase (NOS) inhibitor NO-donating drugs (NI-NODs). Human endothelial cells and human monocyte-based activity screening showed that NI-NODs inhibit IL-1beta production, modulate PGE(2) production, and protect against apoptosis. In a rodent model of colitis, NI-NOD1 and NI-NOD2 potently decreased inflammation. These data show that NI-NODs are effective in both in vitro and in vivo models of inflammation, mimicking the positive effects of low levels of NO and suppressing NOS-induced NO production.     

The influence of mineralogical,chemical and physical properties on grindability of commercial clinkers with high MgO level

This research investigates various methods able to identify possible mineralogical, physical and chemical influences on the grindability of commercial clinkers with high MgO level. The aim of the study is to evaluate the hardness and elastic modulus of the clinker mineral phases and their fracture strength during the comminution processes, comparing samples from clinkers with low MgO level (0.5%) and clinkers with elevated MgO levels (> 5.0%). The study of the influence of mineralogical, chemical and physical properties was carried out using several analytical techniques, such as: optical microscopy, X-ray diffraction with Rietveld refinement (XRD) and X-ray fluorescence (XRF). These techniques were useful in qualifying the different clinker samples. The drop weight test (DWT) and the Bond ball mill grindability test were performed to characterize the mechanical properties of clinkers. Nanoindentation tests were also carried out. Results from the Bond ball mill grindability test were found to be related to the hardness of the mineral phase and to mineralogical characteristics, such as type and amount of inclusions in silicates, belite and alite crystals shape, or microcracked alites. In contrast, the results obtained by the DWT were associated to the macro characteristics of clinkers, such as porosity, as well as to the hardness and mineralogical characteristics of belite crystals in clusters. Hardness instrumented tests helped to determine the Vickers hardness and elastic modulus from the mineral phases in commercial clinkers and produced different values for the pure phases compared to previous publications.     

Selection of phytate-degrading human bifidobacteria and application in whole wheat dough fermentation

Lately, whole wheat products are highly recommended from their healthy properties. However, the presence of phytic acid (InsP(6)) could partly limit their benefits because it decreases the mineral bioavailability due to its chelating properties. The objective of this work was to select strains with high phytate-degrading activity from human feces, and evaluate their suitability for the bread making process. Twenty-three different bifidobacterial strains (13 from infants and 10 from adults) were isolated, belonging to the species Bifidobacterium longum, Bifidobacterium breve and Bifidobacterium catenulatum. The phosphatase and phytase activities of these strains were evaluated as well as their ability to degrade InsP(6) during growth. Then, the fermentative ability of the strain showing the highest phytate-degrading activity (B. longum. BIF307) was determined in whole wheat breadmaking. The use of the selected bifidobacterial strain as starter during whole wheat fermentation resulted in bread with similar technological quality than the control (in absence of bifidobacteria) and crumb with lower levels of inositol phosphates. Therefore, the used of the selected Bifidobacterium strain in whole wheat breadmaking process could provide potential nutritional benefits by decreasing the antinutrient content of the product.     

Lessons learned from Brazilian natural gas industry reform

Over the past decades many countries have reformed their infrastructure industries. Although these reforms have been broadly similar for the most part, aiming at introducing competition in potentially competitive segments, the contexts in which they have been carried out differ. This is due to the past regulatory experience in each country, the maturity of the industry and/or the number of agents when the reform process started. The Brazilian natural gas reform stands out due to the country's singular conditions. The development of the natural gas industry in Brazil was grounded on stepping up supplies through integration with neighboring nations (particularly Bolivia) and establishing a competitive environment by lowering the barriers hampering the arrival of new investors. However, natural gas is located at the crossroads of two main energy chains: oil and hydroelectricity. This article analyzes the Brazilian natural gas reform, and extracts lessons from this process. The low capillarity of transportation and distribution systems continues to be the main bottleneck of the country's natural gas industry. The challenges of the new legal framework are to encourage investments in networks and guarantee supply, to allow the industry to consolidate and mature, against a backdrop of rapid changes in the world market.     

Total extractable phenolic chromatographic index: an overview of the phenolic class contents from different sources of foods

 The extractable phenolic fraction has been studied in a wide group of representative samples from the main food phenolic sources: fruits, vegetables and legumes. After quantitative extraction and quantification of each phenolic compound in the samples, the total extractable phenolic chromatographic index was defined as the sum of all extractable phenolics obtained under conventional conditions, and calculated for the main phenolic classes found in foods: hydroxybenzoic and hydroxycinnamic acids as well as flavonoids. Phenolic acids and flavonoids contents are reported for the food samples studied. The results presented in this work allow an interesting overview of the distribution of the phenolic classes in foods, as well as an approach to the knowledge of the phenolic classes composition in foods. Received: 30 May 2000     

Extending shelf life of chapatti by partial baking and frozen storage

The effect of conventional and partial baking and storage at two different temperatures (ambient and −18 °C) on the texture of wheat flour chapatties was evaluated using tensile deformation and the extent of retrogradation was studied using DSC. The extensibility of the conventionally baked chapatti decreased by 58.7% and 20.15%, respectively after storage of 24 h at ambient and frozen temperature. The partially baked chapatti showed a much lower decrease of 3.7% and 0.01% in extensibility when stored under the same conditions. Chapatties, both conventionally and partially baked stored at ambient temperature showed higher retrogradation enthalpy than their counterparts kept at −18 °C. Extended frozen storage of the chapattis from partially baked chapatti resulted in a progressive increase in the extensibility whereas the extensibility of the conventionally baked chapatties was not affected. Lowest water absorption index of 4.60 was observed in partially baked chapatti stored for 24 h at ambient temperature indicating that maximum retrogradation (4.19 J/g) had taken place. Frozen partially baked chapatties after thawing and rebaking exhibited texture equivalent to that of conventionally baked chapatties therefore they could be considered a better option than frozen conventionally baked chapatties for retarding staling.     

Chelating,antioxidant and antiproliferative activity of <Emphasis Type="Italic">Vicia sativa</Emphasis> polyphenol extracts

The metal chelating activity, antioxidant properties, and the effect on cell growth of a polyphenol extract from Vicia sativa have been investigated, and compared to those of soybean. The extracts from V. sativa seeds contained three and five times more polyphenols and flavonoids than soybean, respectively. The soybean polyphenol extracts showed higher copper and iron chelating activity than those from V. sativa, although polyphenols from V. sativa were more effective in preventing β-carotene oxidation and showed higher reducing power and scavenging activity than soybean polyphenols. In addition, V. sativa polyphenols were toxic to THP-1 leukemic cells, as opposed to polyphenols extracted from soybean that did not show any antiproliferative activity at similar concentrations. In conclusion, V. sativa polyphenol extracts show promising antioxidant and antiproliferative activities that may be of interest from a functional point of view and for the revalorization of this ancient crop.     

Optimization of a slurry dispersion method for minerals and trace elements analysis in infant formulae by ICP OES and FAAS

Infant formula developed by manufacturers requires a rigorous control of composition, particularly those elements added routinely in an attempt to mimic the mineral composition of human milk. A total of 97 different types of powdered infant formulae (preterm, adapted starter, adapted follow-up, toddler, specialised and soy-based formulae) commercially available in Spain were studied. It is noteworthy great differences in mineral (Ca, P, Mg) and trace element (Zn, Fe, Cu, Mn) contents found between analysed and listed in label information. The development of a fast, simple and direct slurry method for the determination of these essential micronutrients in infant formula by inductively coupled plasma optical emission spectrometry (ICP OES) and flame atomic absorption spectrometry (FAAS) was performed in order to help in quality control tasks. Infant formula samples were solubilised using different amounts of several different solvents. An addition of 250 μL of a solution 10% tetramethylammonium hydroxide and 25% ammonium hydroxide were required for the accurate quantification of Ca and P, Mg, Zn, Fe, Cu and Mn, respectively. The standard reference material 1549 non-fat milk powder was solubilised to compare the validity of assayed methodology following slurry nebulisation and traditional microwave-assisted acid digestion method. Good agreement of the analytical results by both ICP OES and FAAS, with the certified values was obtained. Method performance parameters (accuracy, precision and methodological detection limits) were determined for studied elements to check the quality and usefulness of the optimised slurry method. The analytical procedure was applied successfully to the analysis of a representative group of infant formulae. Levels of analysed elements were graphically represented, showing an acceptable comparability between slurry and acid-mineralisation method set by linear correlation coefficients and slopes close to the unit. The described simple and slurry method is appropriate, as an attractive alternative, for routine control analysis of added essential elements in infant formulae regardless of predominant protein type used in manufacture.