A hierarchical approach to adaptive local refinement in isogeometric analysis

Adaptive local refinement is one of the key issues in isogeometric analysis. In this article we present an adaptive local refinement technique for isogeometric analysis based on extensions of hierarchical B-splines. We investigate the theoretical properties of the spline space to ensure fundamental properties like linear independence and partition of unity. Furthermore, we use concepts well-established in finite element analysis to fully integrate hierarchical spline spaces into the isogeometric setting. This also allows us to access a posteriori error estimation techniques. Numerical results for several different examples are given and they turn out to be very promising.     

On the composition of the essential oils of Artemisia genipi Weber and Artemisia umbelliformis Lam

Summary A comparison was made between the essential oil ofArtemisia genipi Weber, a rare and expensive plant employed in manufacturing liqueurs in Piemonte and Aosta Valley, and that ofArtemisia unbelliformis Lam., a less rare and costly plant, which often is used substitute the former. The essential oils, obtained by steam-distillation of the aerial parts of the two plants, after separation into fractions on a silica gel column, were investigated by means of GLC and GLC-MS. -Pinene,-thujone,-thujone and terpinen-4-ol were the main components ofArtemisia genipi Weber, totalling 63.1%.-Thujone,-thujone, sabinyl isovalerate and spathulenol were the main components ofArtemisia unbelliformis Lam., totalling 71.3%. Several other minor constituents have been identified and are reported.

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Über die Zusammensetzung der ätherischen Öle von Artemisia genipi Weber und Artemisia umbelliformis Lam

Zusammenfassung Es wurde ein Vergleich zwischen dem ätherischen Öl derArtemisia genipi Weber, einer seltenen und wertvollen in der Likörproduktion in Piemont und im Aostatal verwendeten Pflanze und dem vonA. umbelliformis Lam., einer weniger seltenen und weniger kostspieligen Pflanze gemacht. Die ätherischen Öle, durch Wasserdampfdestillation aus Blättern und Blüten von den zwei Pflanzen erhalten, wurden nach Säulenchromatographie an Kieselgel mittels GLC und GLC-MS analysiert.-Pinen,-Thujon,-Thujon und Terpinen-4-ol bilden 63,1% des Öls vonArtemisia genipi Weber;-Thujon,-Thujon, Sabinylisovalerianat und Spathuleol bilden 71,3% des Öls vonA. umbelliformis Lam. Darüber hinaus wurden weitere Bestandteile identifiziert und beschrieben.

     

Antibiotic-loaded acrylic bone cements: An in vitro study on the release mechanism and its efficacy

An in vitro study was carried out in order to investigate the antibiotic release mechanism and the antibacterial properties of commercially (Palacos® R + G and Palacos® LV + G) and manually (Palacos® R + GM and Palacos® LV + GM) blended gentamicin-loaded bone cements.Samples were characterized by means of scanning electron microscopy (SEM) and compression strength was evaluated. The antibiotic release was investigated by dipping sample in simulated body fluid (SBF) and periodically analyzing the solution by means of high pressure liquid chromatography (HPLC). Different antibacterial tests were performed to investigate the possible influence of blending technique on antibacterial properties.Only some differences were observed between gentamicin manually added and commercial ones, in the release curves, while the antibacterial effect and the mechanical properties seem to not feel the blending technique.     

Overview of the first AGILE catalog of high-confidence gamma-ray sources

AGILE is an Italian Space Agency mission launched in April 2007, devoted to γ-ray observations in the 30 MeV–50 GeV energy range, with simultaneous X-ray imaging capability in the 18–60 keV band. During its first year in orbit AGILE surveyed the γ-ray sky and detected many galactic and extragalactic sources. The first catalog of high-confidence γ-ray sources detected by AGILE during observations performed from July 9, 2007 to June 30, 2008, for energies greater than 100 MeV was recently published [1], and preliminary versions of the catalog were published on the AGILE Data Center webpage to allow AGILE Cycle-2 guest observers to benefit of the Catalog in the preparation of their proposals. We present here the main results of the final catalog, that includes 47 high-confidence sources, 21 of which are associated with confirmed or candidate pulsars, 13 with Blazars (7 FSRQ, 4 BL Lacs, 2 unknown type), 2 with HMXRBs, 2 with SNRs, 1 with a colliding-wind binary system, 8 with unidentified sources.     

Mucosal immunogenicity of genetically detoxified derivatives of heat labile toxin from Escherichia coli

Using a fixed dose of antigen, the immune response to detoxified mutants of LT-WT following intranasal (i.n.), subcutaneous (s.c.) and oral (i.g.) immunisation has been studied. When given i.n., both LT-WT and mutant toxin, K63, generated significant levels of toxin-specific IgG in the serum, and the levels of IgA in nasal and lung lavages were greater than those induced by rLT-B. In comparison, i.g. immunisation of mice with a similar quantity of either LT-WT or K63 toxin induced barely detectable levels of IgG in the sera. However, if the amount of protein used for i.g. immunisation was increased tenfold, relatively good levels of toxin-specific IgG were induced in the sera by both LT-WT or K63. Low levels of toxin-specific IgA were also observed in intestinal washes from these mice. Western blotting of the sera, using the native toxin as an antigen, demonstrated the presence of both anti-A and anti-B subunit antibodies. Most significantly, toxin-neutralising antibodies were induced in the serum, with the strongest activity being induced by the LT-WT, an intermediate activity induced by mutant K63 and a lower response by rLT-B. Together, these data show that ADP-ribosyltransferase is not necessary for mucosal immunogenicity of these proteins, and that the i.n. route of immunisation is more effective than the i.g. route of immunisation for the generation of both systemic (IgG) and mucosal (IgA) immune responses.     

Human Serine Racemase Weakly Binds the Third PDZ Domain of PSD-95

Human serine racemase (hSR) is a pyridoxal-5′-phosphate (PLP)-dependent dimer that catalyzes the formation of D-serine from L-serine, as well as the dehydration of both L- and D-serine to pyruvate and ammonia. As D-serine is a co-agonist of N-methyl-D-aspartate receptors (NMDARs), hSR is a key enzyme in glutamatergic neurotransmission. hSR activity is finely regulated by Mg²⁺, ATP, post-translational modifications, and the interaction with protein partners. In particular, the C-terminus of murine SR binds the third PDZ domain (PDZ3) of postsynaptic density protein 95 (PSD-95), a member of the membrane-associated guanylate kinase (MAGUK) family involved in the trafficking and localization of glutamate receptors. The structural details of the interaction and the stability of the complex have not been elucidated yet. We evaluated the binding of recombinant human PSD-95 PDZ3 to hSR by glutaraldehyde cross-linking, pull-down assays, isothermal titration calorimetry, nuclear magnetic resonance, and enzymatic assays. Overall, a weak interaction was observed, confirming the binding for the human orthologs but supporting the hypothesis that a third protein partner (i.e., stargazin) is required for the regulation of hSR activity by PSD-95 and to stabilize their interaction.     

Nanostructured bimetallic alloys prepared via mechanochemical synthesis as PEMFC electrocatalysts for automotive applications

Pt–Co alloys prepared by high energy ball milling synthesis were tested as electrocatalysts for hydrogen fueled Polymer Electrolyte Membrane Fuel Cells (PEMFC). In the present contribution we report on the first results regarding the electrochemical behaviour of two samples of Pt–Co alloys. One sample contains 20 wt.% alloy Pt:Co in the molar ratio 0.25:0.75 and C 80 wt.% and the second one Pt:Co in the molar ratio 0.75:0.25 and C 80 wt.%. The electrochemically active surface (EAS) was determined by cyclic voltammetry data while the electrocatalyst performance in a real cell was obtained by assembling Membrane Electrode Assemblies (MEAs) with the considered sample at the cathode. The results obtained, though indicating a lower performance than all-Pt catalysts, are quite interesting as they point out the importance of the C/Pt, Nafion/Pt and Pt/Co ratios that exert a deep influence onto the cell performance.