Change in the Physicochemical Properties of Nanocrystalline Powder Based on ZrO2 in the Presence of a Mineralizing Agent

The change in physicochemical properties of nanocrystalline powder of the composition ZrO₂ ― 3 mole% Y₂O₃ in the presence of aluminum fluoride is studied. The starting powder is prepared by a complex method including elements of hydrothermal synthesis and sol-gel technology. It is established that these conditions expand the temperature limits for the existence of ZrO₂ monoclinic solid solution. Transformation is connected with adsorption of fluorine at the ZrO₂ surface, diffusion in the solid phase, and a reduction in anion vacancy concentration.     

Analysis of the internal friction spectra of high purity aluminium at medium temperatures

The internal friction spectra of high purity aluminium (99.999%) has been thoroughly studied but, at the present time, there is no agreement about the number of peaks at medium temperatures and the number of components of each peak. This paper discusses the reasons for that controversy and summarizes the relaxation processes found in the internal friction spectra. Some authors have assumed that the P₂ peak (also called Kê peak) is formed by two components, one associated to a mechanism of dislocation mobility and the other to grain boundary sliding. However, this assertion is based on weak experimental evidence, which is critically reviewed in this work. The fitting methods used to decompose the internal friction spectra have also been discussed, since some of them can generate spurious components and lead to equivocal conclusions. Another point of great interest that has remained unclear concerns the shifts of the temperature of the peaks observed by many authors, which are explained in this paper with the help of some mechanisms of dislocation mobility. Several specific experimental measurements in 99.999% aluminium and 99.9999% aluminium doped with 10 ppm of copper are presented to clarify these questions. It is concluded that P₂ is composed of just one component and is associated to a mechanism of dislocation mobility. In addition, we have determined that there are only three peaks in the medium temperature range, namely P₁, P₂ and P₃.     

Effects of tiger nut (Cyperus esculentus) milk liquid co‐products on the quality of pork burgers

Co‐products from the tiger nut milk industry can be given added value if they are used in the manufacturing process of other food products. The aim of this study was to analyse the effect of using tiger nut milk liquid co‐product as a substitute for the water added to pork burger formulations. The results showed that its use in pork burger delayed lipid oxidation and improved cooking properties (less shrinkage), while no significant changes in nutritional value were observed. Pork burgers containing tiger nut liquid co‐product were perceived to be juicier and less fatty than the control, contributing to higher scores for overall liking.     

“What is,Becomes What is Right”: A Conceptual Framework of Newcomer Legitimacy for Online Discussion Communities

Online community newcomers can face challenges in community participation, acceptance and fostering member relationships. Consequently, a crucial behavioral strategy for community acceptance identified by previous research is legitimacy. However, current conceptions lack classification and structure, and have a narrow focus. A broader scope for investigating legitimacy is needed for improved theoretical and practical application. This research expands on newcomer legitimacy by classifying newcomer behavior in 4 parenting and cycling discussion communities using directed content analysis. The analysis developed a newcomer legitimacy conceptual framework with categories including geographical, contextual, cultural, testimonial, lurking and external legitimacy. This research offers a valuable contribution by classifying existing theory, developing new theory, and providing a conceptual framework to guide future studies of newcomer behavior.     

Effect of Dispersity and Porous Structure of TiO2 Nanopowders on Photocatalytic Destruction of Azodyes in Aqueous Solutions

Photocatalytic activity of TiO2 nanopowders of anatase modification with various particle sizes and specific surface areas has been studied in the process of photocatalytic decolorization of aqueous solutions of methylene blue and direct blue 2C azodyes. By means of scanning electron microscopy and low-temperature N2 adsorption method, it was found that TiO2 nanopowders have the particles size of 5-120 nm with the specific surface area of 15-120 m2·g^-1. The used TiO2 samples are characterized by mesoporous structures with average pore size of 4.3-14.9 nm. The photocatalytic activity of TiO2 was evaluated via decolorization of azodyes solutions. It was shown that the efficiency of decolorization symbatically changes with the dye adsorption value on TiO2 surface and the degree of decolorization rises when the surface area of TiO2 nanopowders increases. It was found that TiO2 photocatalytic activity essentially depends on adsorption interactions between the dye molecules and catalytic active centers on TiO2 surface, and these interactions, in turn, are greatly affected by pH of the solution.     

Amino acids evolution during ripening of goats' milk cheese manufactured with different coagulants

Powdered plant coagulant obtained from the cardoon flowers ( Cynara cardunculus ) was compared with calf rennet for the manufacture of traditional raw goats' milk cheese, by determining differences in the profiles of the amino acids throughout the ripening period. Derivatisation with o -phtaldialdehyde and a C₁₈ column were used for chromatographic separations. In order to establish the relationships between the different variables and to detect the most important causes of variability, principal component analysis was applied to the free amino acids data, which reduced to two dimensions where cheese samples from 2 to 60 days and cheeses from 90 to 120 days were distributed dependently of ripening time and coagulant used. Leu, Val, Lys, Gly, Tyr and Asp were correlated with PC1, which separated the samples according to their ripening time. Arg, His, Trp, Ser and Thr were correlated with PC2, which separated the samples according to the coagulant used.     

Drastic Attenuation of Pseudomonas aeruginosa Pathogenicity in a Holoxenic Mouse Experimental Model Induced by Subinhibitory Concentrations of Phenyllactic acid (PLA)

The discovery of communication systems regulating bacterial virulence has afforded a novel opportunity to control infectious bacteria without interfering with growth. In this paper we describe the effect of subinhibitory concentrations of phenyllactic acid (PLA) on the pathogenicity of Pseudomonas aeruginosa in mice. The animals were inoculated by oral (p.o.), intranasal (i.n.), intravenous (i.v.) and intraperitoneal (i.p.) routes with P. aeruginoasa wild and PLA-treated cultures. The mice were followed up during 16 days after infection and the body weight, mortality and morbidity rate were measured every day. The microbial charge was studied by viable cell counts in lungs, spleen, intestinal mucosa and blood. The mice batches infected with wild P. aeruginosa bacterial cultures exhibited high mortality rates (100 % after i.v. and i.p. route) and very high cell counts in blood, lungs, intestine and spleen. In contrast, the animal batches infected with PLA treated bacterial cultures exhibited good survival rates (0 % mortality) and the viable cell counts in the internal organs revealed with one exception the complete abolition of the invasive capacity of the tested strains. In this study, using a mouse infection model we show that D-3-phenyllactic acid (PLA) can act as a potent antagonist of Pseudomonas (P.) aeruginosa pathogenicity, without interfering with the bacterial growth, as demonstrated by the improvement of the survival rates as well as the clearance of bacterial strains from the body.     

What indicators do (or do not) tell us about Regional Innovation Systems

This paper analyses some of the methodologies and R&D and innovation indicators used to measure Regional Innovative Capacity in Spain for the period 1996–2000. The results suggest that the approaches examined are not sufficiently rigorous; they vary depending on the methodology and indicators employed. Therefore, we would suggest that the right balance between quantitative and qualitative approaches could produce a better evaluation of innovation system performance which would be more useful to policy makers and other stakeholders.     

Deacidification of olive oil by countercurrent supercritical carbon dioxide extraction: Experimental and thermodynamic modeling

Supercritical carbon dioxide was used as an extractive solvent to remove free fatty acids from cold-pressed olive oil. Crude oil of different acidity content (from 0.5 to 4.0 wt%) was extracted in a packed column at 313 K and pressures of 180, 234 and 250 bar. The group contribution equation of state was employed to simulate the separation process, representing the oil as a simple pseudo-binary oleic acid + triolein mixture. Despite the simple representation of oil composition to simulate the deacidification process, a satisfactory agreement between the experimental and calculated yields and acidity of raffinates was obtained. The thermodynamic model was employed to study a continuous countercurrent multistage extraction process which yielded a raffinate having acidity lower than 0.7 wt%, when crude olive oil with different FFA content was processed.     

Effect of salt content and processing conditions on volatile compounds formation throughout the ripening of Iberian ham

Volatile compounds evolution throughout the ripening of dry-cured Iberian hams with different salt content (6% vs. 3% of salt w/w) and processing temperature conditions (traditional processing vs. modified processing) was studied using solid-phase microextraction coupled to a direct extraction device (SPME-DED). Traditional processing implied an increase in the temperatures (28 °C) during an intermediate period (drying phase) of the processing, while in the modified process temperature was maintained at 19 °C. Enhanced temperatures in the traditional processing did not increase compounds from lipid oxidation such as hexanal, heptanal, octanal or nonanal. Salt level did not show any effect on volatiles during processing except for 2-pentylfuran during the drying stage (day 177). Although none of the volatile compounds monitored showed significant differences in the final sampling, the ratio between hexanal and octanal plus nonanal, that of hexanal and 3-methylbutanal plus 2-methylbutanal and that of hexanal and γ-octalactone were significantly higher in hams processed under modified system, in which the temperature is lower in the drying stage.