Phase stability for the Cu–Zr system: First-principles,experiments and solution-based modeling

First-principles calculations and experimental methods were employed to investigate the relative stability of intermetallic phases in the Cu–Zr system. Computed enthalpies of formation indicate that Cu₅₁Zr₁₄-β and CuZr₂-C11_b are stable phases, while Cu₅Zr-C15_b, Cu₁₀Zr₇-? and CuZr-B2 are metastable at 0 K. Heat treatment and microanalysis revealed two important findings which clarify the phase equilibria. First, the stability range for the Cu₅Zr-C15_b phase was found to have a lower bound associated with an eutectoid invariant between 802 and 955 K, below which it decomposes to face-centered cubic Cu plus Cu₅₁Zr₁₄-β. Second, the Cu₅Zr₈ phase, previously reported as stable, was not observed in a Cu–56.4 at.% Zr alloy after holding at 955 and 1036 K for >100 h. This phase, therefore, was not considered to be stable. Based on computational and experimental results, Gibbs free energies were modeled, including the Cu₂Zr-σ, Cu₂₄Zr₁₃-μ and metastable CuZr-(B19′ and B33) phases. The associated phase diagrams are presented.     

Survey of qualitative traits of European sea bass cultivated in different rearing systems

The purpose of this study was to evaluate the main qualitative traits of European sea bass fattened in farms adopting different rearing techniques (offshore cages, inshore cages, land‐based basins) but fed the same diets in each production cycle, in a three year survey (2006, 2007, 2008). Three farms were chosen for each rearing technique and two sampling sessions of ten fish each were carried out for each rearing cycle. Proximate composition, fatty acid profile, and cholesterol content were evaluated in the fillet of marketable size fish as well as morpho‐biometric parameters and indices. Diets administered in 2008 had higher amounts of lipids, lower proportions of n–3 polyunsaturated fatty acids (PUFA) and higher proportions of n–6 PUFA compared to 2006 and 2007 diets. The chemical and fatty acid composition of the fish fillet was affected by the diet composition: fish fattened in 2008 exhibited statistically higher amounts of fat and cholesterol, lower proportions of n–3 PUFA and higher proportions of n–6 PUFA in comparison with fish cultivated in 2006 and 2007. Fish cultivated in cages, both offshore and inshore cages, exhibited leaner fillets, lower amounts of cholesterol and higher proportions of n–3 PUFA than fish cultivated in basins. Practical applications: In this study we have analyzed the combined effects of feeding and rearing systems of sea bass in a 3‐year survey for the first time. The results showed that feeding is the main factor affecting fish quality as regards both the chemical composition and the fatty acid profile. The partial substitution of fish meal and fish oil with vegetable sources, with the aim of saving the wild fish biomass as well as formulating less expensive diets, strongly alters the fillet composition. We also showed that the rearing system of fish in offshore cages makes it is possible to obtain better quality products.     

Involvement of ERK,Akt and JNK signalling in H2O2‐induced cell injury and protection by hydroxytyrosol and its metabolite homovanillic alcohol

The olive oil polyphenol, hydroxytyrosol (HT), is believed to be capable of exerting protection against oxidative kidney injury. In this study we have investigated the ability of HT and its O‐methylated metabolite, homovanillic alcohol (HVA) to protect renal cells against oxidative damage induced by hydrogen peroxide. We show that both compounds were capable of inhibiting hydrogen peroxide‐induced kidney cell injury via an ability to interact with both MAP kinase and PI3 kinase signalling pathways, albeit at different concentrations. HT strongly inhibited death and prevented peroxide‐induced increases in ERK1/2 and JNK1/2/3 phosphorylation at 0.3 μM, whilst HVA was effective at 10 μM. At similar concentrations, both compounds also prevented peroxide‐induced reductions in Akt phosphorylation. We suggest that one potential protective effect exerted by olive oil polyphenols against oxidative kidney cell injury may be attributed to the interactions of HT and HVA with these important intracellular signalling pathways.     

Measuring $I/Q$ Impairments in WiMAX Transmitters

This paper presents a new method for measuring the I /Q impairments affecting the worldwide interoperability for microwave access (WiMax) transmitters through the analysis of the signal acquired through a general-purpose I /Q receiver. Based on a model of the effects of the I /Q impairments on the output signal that is suitable for orthogonal frequency-division multiplexing (OFDM) systems like WiMax, the method is designed to correctly take into account the peculiarities of systems compliant with the IEEE 802.16-2004 standard, such as the potentially noxious effects of the impairments on signal normalization and threshold decisions. The results of the experiments carried out on the standard-compliant signals are given.     

Hydrogels from scleroglucan and ionic crosslinkers: Characterization and drug delivery

The polysaccharide scleroglucan (Sclg), exploited as a matrix suitable for modified drug delivery, was crosslinked in the presence of three ions: borate, aluminum, and iron. A rheological investigation indicated the main differences between the hydrogels in their viscoelastic linear response: the Sclg/borax system showed the highest strength when deformed by elongation, whereas the strength of the other systems broke down, in terms of viscosity, at much lower values of the imposed strain. Tablets prepared from the gels showed remarkable differences in their water uptake and dimensional swelling. On the other hand, the tablets, loaded with drugs of different steric hindrances, showed similar release behavior, regardless of the crosslinking agent. Scanning electron microscopy analysis was related to the delivery and rheological profiles. Texture analysis, carried out on tablets swollen for 5 h, showed different values of cohesion. Furthermore, when the generalized Maxwell model was applied to the relaxation data, the obtained mechanical spectra showed a more pronounced solidlike character of the Sclg/iron network in comparison with the prevailing viscous behavior of the other matrices. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The Biomolecular Basis of Adipogenic Differentiation of Adipose-Derived Stem Cells

There is considerable attention regarding the role of receptor signaling and downstream-regulated mediators in the homeostasis of adipocytes, but less information is available concerning adipose-derived stem cell (ASC) biology. Recent studies revealed that the pathways regulating ASC differentiation involve the activity of receptor tyrosine kinases (RTKs), including fibroblast growth factor, vascular endothelial growth factor, ErbB receptors and the downstream-regulated serine/threonine protein kinase B (Akt) and phosphatase and tensin homolog (PTEN) activity. RTKs are cell surface receptors that represent key regulators of cellular homeostasis but also play a critical role in the progression of cancer. Many of the metabolic effects and other consequences of activated RTKs are mediated by the modulation of Akt and extracellular signal-regulated protein kinases 1 (Erk-1) signaling. Akt activity sustains survival and the adipogenic differentiation of ASCs, whereas Erk-1 appears downregulated. The inhibition of FGFR-1, EGFR and ErbB2 reduced proliferation, but only FGFR-1 inihibition reduced Akt activity and adipogenesis. Adipogenesis and neovascularization are also chronologically and spatially coupled processes and RTK activation and downstream targets are also involved in ASC-mediated angiogenesis. The potentiality of ASCs and the possibility to modulate specific molecular pathways underlying ASC biological processes and, in particular, those shared with cancer cells, offer new exciting strategies in the field of regenerative medicine.