Dynamic Spatial Equilibrium Models: an Application to the Natural Gas Spot Markets

Networks and Spatial Economics - European gas markets have gone through profound restructuring processes in the last 20 years. Directive 98/30/EC represented the first attempt to liberalize this...     

The dimerization domain of LFB1/HNF1 related transcription factors: a hidden four helix bundle?

LFB1/HNF1 and LFB3/HNF1ß bind DNA as dimers and formheterodimers together in vivo and in vitro. The dimerizationdomain has been located in both proteins in the 32 N-terminalresidues. In previous papers we have described the conformationalstability as determined by CD and the secondary structure byNMR studies of a peptide with the amino acid sequence of thedimerization domain of LFB1/ HNF1. This study presents a morecomplete characterization of similar synthetic peptides spanningthe LFB3/HNF1ß dimerization domain and the /ßheterodimer. The HNF1 peptides represent an example of structureswhich cannot be determined by NOE data alone because they arenot sufficient to define one unique solution. An approach ispresented which combines NMR data, the protein structure databaseand structural analyses according to known principles of proteinstructure. On this basis we are able to determine possible solutionsand to identify a four helix bundle as the structure most consistentwith the experimental evidence.     

Catalytic MTO-based C–H insertion reactions of hydrogen peroxide: an investigation on the polymeric support role in heterogeneous conditions

Polymer-supported methyltrioxorhenium (MTO) compounds are shown to act as efficient and selective catalysts for the oxy-functionalization of C–H bonds in representative hydrocarbon derivatives (leading to the corresponding alcohols or ketones), using H₂O₂ as oxidant. The different supports used for the heterogenation of MTO, such as poly(4-vinylpyridine), poly(4-vinylpyridine)-N-oxide and polystyrene resins, all showed different catalytic behaviour in terms of substrate conversion and product yield, depending on the experimental conditions used. It is noteworthy that the novel heterogeneous catalysts were found to be stable, it being possible to effect their recover and recycle at least five times without appreciable loss of activity.     

Oxidation of 3,4-dihydroxybenzoic acid by means of hydrogen peroxide in aqueous goethite slurry

The oxidation by H2O2 of 3,4-dihydroxybenzoic acid (3,4-DHB) in aqueous/goethite slurry at varying operating conditions (catalyst load, temperature, pH, substrate and hydrogen peroxide starting concentration) is investigated. At adopted catalyst loads the observed kinetic developments are consistent with a non-radicalic oxidation mechanism involving the interaction between hydrogen peroxide and 3,4-DHB acid both adsorbed on the active sites of the catalyst. The temperature dependence of rate parameters for the proposed model is also assessed.     

Sustainability of steel structures: towards an integrated approach to life-time engineering design

Nowadays, the construction sector is more and more oriented toward the promotion of sustainability in all its activities. The goal to achieve is the optimization of performances, over the whole life-cycle, with respect to environmental, economic and social requirements. According to the latest advances, the concept of sustainability applied to constructions covers a number of branches such as life-cycle costing, ecology, durability and even structural design. Several procedures and design tools have been implemented in the framework of international research. Indeed the current trend in civil engineering research is moving towards life-time engineering, with the aim to implement integrated methodologies to consider as a whole all the sustainability requirements according to time-dependent multi-performance-based design approaches. Following a general introduction of the concept of sustainability applied to constructions, this paper presents an overview of life-time engineering methodologies according to the current state-of-the-art. In particular the methods currently received by International Standards are discussed. A special focus is devoted to the durability design of metal structures with respect to the degradation phenomena able to impair the structural capacity over time. Finally a proposal towards an integrated approach to life-time engineering design of steel structures and needs for further advances are presented.     

Influence of Zinc on Distiller's Yeast: Cellular Accumulation of Zinc and Impact on Spirit Congeners

Accumulation of zinc by a whisky distilling yeast strain of Saccharomyces cerevisiae was studied during fermentation of malt wort and synthetic defined medium. Zinc uptake by yeast cells was very rapid in malt wort, as zinc (0.32 μg/mL) was completely removed from the fermentation medium within one hour. The type of fermentable carbohydrate had an impact on the kinetics of zinc accumulation, with maltose most effective at enhancing metal uptake at zinc concentrations above 3.2 μg/mL. Enriching yeast cells with zinc by “preconditioning” impacted on the production of flavour congeners in the distillates produced from fermented cultures. Such distillates were characterised by an altered flavour and aroma profile. In particular, the production of some higher alcohols increased when yeast cells were preconditioned with zinc. This phenomenon is yeast strain related. Industrial fermentation processes, including brewing and distilling, may benefit from optimization of zinc bioavailability in yeast cultures resulting in more efficient fermentations and improved product quality.     

Measurement of intrinsic properties of amyloid fibrils by the peak force QNM method

We report the investigation of the mechanical properties of different types of amyloid fibrils by the peak force quantitative nanomechanical (PF-QNM) technique. We demonstrate that this technique correctly measures the Young's modulus independent of the polymorphic state and the cross-sectional structural details of the fibrils, and we show that values for amyloid fibrils assembled from heptapeptides, α-synuclein, Aβ(1-42), insulin, β-lactoglobulin, lysozyme, ovalbumin, Tau protein and bovine serum albumin all fall in the range of 2-4 GPa.