Crystallization and melting properties of extra virgin olive oil studied by synchrotron XRD and DSC

Crystallization and melting properties of triacylglycerols in extra virgin olive oil were studied by using synchrotron X‐ray diffraction (XRD) and differential scanning calorimetry (DSC). The phase transitions were monitored by cooling and heating the samples at 2°C/min from 60 to ?60°C and vice versa. Upon cooling, a first DSC endothermic peak was recorded at ?9.6°C followed by one at ?33.5°C. These thermal events were associated to the formation of two different structures: a triple‐chain length (3L) having a c parameter of about 58.38 Å and a quadruple chain length structure (4L) with a c parameter of about 89.99 Å, respectively. Both structures evidenced a cell packing arrangement ascribable to a β′ form. During heating, part of the metastable β′ crystals rearranged into the more thermodynamically stable β form. Then, upon further heating, the sequential melting of the two crystal structures was observed. The melting was completed at 10.7°C. Beside this interpretation of XRD data, a model considering a cell with a c parameter of about 170 Å and a hexagonal crystal system was proposed. Even if more research is needed to validate this approach, it allowed all XRD events recorded during the experiments to be described. See commentary by Chiavaro [p. 267–269], http://dx.doi.org/10.1002/ejlt.201200415     

Intangible Asset Dynamics and Firm Behaviour

We study the adoption of different patterns of intangible asset (IA) accumulation in manufacturing firms. Contrary to most of the previous literature, we find such patterns to be highly differentiated. In particular, we identify three types of firm behaviour: high and persistent, low and persistent, and discontinuous. We link the capability-based view of the firm to theories of asset complementarities and market signalling to explain how firm-specific traits affect such behaviours. We obtain the following results: first, the persistent accumulation of IAs is favoured by the internal availability of highly skilled personnel; second, firms with (a) large IA base and (b) high propensity to exploit complementarities in the asset stocks are more likely to persistently accumulate IAs than to discontinuously or never accumulate IAs and third, the adoption of quality management standards facilitates the accumulation of IAs, especially if this is done discontinuously. This paper adds to the previous literature in two ways: first, it highlights the existence of great heterogeneity in the dynamics of IA accumulation and, second, it provides an explanation for such heterogeneity.     

Spectral analysis of Serpinskij carpet-like prefractal waveguides and resonators

Exact results on some modal properties of waveguides and resonators is studied, whose geometry is derived from "Serpinskij carpet-like" prefractals (Serpinskij carpet and sponge; Menger sponge). The study is biased to the closed-form computation of specific resonances and eigenmodes (called "dia-periodic"), and to the relation existing between their topology and the existence of a finite set of transverse electromagnetic modes.     

Endosomal Escape of Polymer‐Coated Silica Nanoparticles in Endothelial Cells

Current investigations into hazardous nanoparticles (i.e., nanotoxicology) aim to understand the working mechanisms that drive toxicity. This understanding has been used to predict the biological impact of the nanocarriers as a function of their synthesis, material composition, and physicochemical characteristics. It is particularly critical to characterize the events that immediately follow cell stress resulting from nanoparticle internalization. While reactive oxygen species and activation of autophagy are universally recognized as mechanisms of nanotoxicity, the progression of these phenomena during cell recovery has yet to be comprehensively evaluated. Herein, primary human endothelial cells are exposed to controlled concentrations of polymer‐functionalized silica nanoparticles to induce lysosomal damage and achieve cytosolic delivery. In this model, the recovery of cell functions lost following endosomal escape is primarily represented by changes in cell distribution and the subsequent partitioning of particles into dividing cells. Furthermore, multilamellar bodies are found to accumulate around the particles, demonstrating progressive endosomal escape. This work provides a set of biological parameters that can be used to assess cell stress related to nanoparticle exposure and the subsequent recovery of cell processes as a function of endosomal escape.     

G.p.c. and viscometric investigation on grafting of styrene-co-acrylonitrile polymer to ethylene propylene elastomer

Ethylene-co-propylene polymer (EPM) has been grafted by styrene-acrylonitrile (SAN). The grafting and molecular parameters of the graft polymers (EPM-g-SAN) have been investigated by means of viscometry and g.p.c. measurements. Viscometric molecular weight ($\text{M}\text{?}{}_{\mathrm{v.g}}$) parameters of the elastomeric backbone of the graft polymers and distribution of SAN content in relation to grafting conditions have been determined. Viscometric measurements in solvent mixtures have been made on EPM-g-SAN to study the functions of the SAN/EPM ratio and the molecular weight of grafted SAN. Viscometric behaviour is dependent on each of these factors.     

Economic crisis and firm exit: do intangibles matter?

ABSTRACT

The financial crisis has caused many business closures, especially in the periphery of the European Monetary Union. In this paper, we use original firm-level Italian data to explore the role of intangibles in limiting firm exit during the crisis. While intangibles strengthen firms’ resilience, i.e. the ability to cope with unexpected shocks, they also entail sunk costs, which expose firms to greater financial risk. In the longer term, when access to external finance is critical for survival, we expect intangibles to play a positive role only if combined with a solid financial structure. Our results support these hypotheses: intangibles directly reduce the probability of firm exit during the initial phase of the crisis (before 2010). At later stages, the beneficial effect of intangible assets is conditional on the firm exhibiting a solid pre-crisis financial status. Managerial and policy implications are discussed.     

Effect of Lipid Physical State of Palm Derivatives on β‐Carotene Bleaching

This research was addressed to study the effect of lipid physical state on bleaching kinetics of β‐carotene. To this aim, β‐carotene was added to palm oil and palm stearin and the samples were stored at increasing temperatures allowing different degree of crystallization. Phase transition properties of palm derivatives were studied by differential scanning calorimetry and synchrotron X‐ray diffraction, whereas β‐carotene bleaching kinetics were followed by measuring color changes. Bleaching proceeded at comparable rate in palm oil and palm stearin containing systems stored at 20 and ?18 °C, whereas the color changes showed a maximum rate at 4 °C in palm stearin samples and at ?7 °C in palm oil systems. Arrhenius plot clearly highlighted deviations from the linearity underlining the crucial role of lipid physical properties in determining the bleaching rate. The location and the compartmentalization of β‐carotene in the fat lattice could affect its chemical stability.     

Effect of monoglyceride organogel structure on cod liver oil stability

The aim of the present research was to study the influence of monoglyceride organogel structure on the oxidative stability of cod liver oil. To this purpose, organogels were prepared by mixing increasing percentages of saturated monoglycerides with cod liver oil, chosen as a natural source of polyunsaturated fatty acids. The structural characteristics of the systems as well as the kinetics of oxidation product formation were evaluated.Increasing the monoglyceride concentration, organogels show an increase of the rheological parameters highlighting different macroscopic structures. On the contrary, at nano-level the systems present the same molecular organization consisting in monoglyceride molecules crystallized in the β-phase and self-assembled in lamellae with a width of around 46 Å.The presence of the monoglyceride network shows a double effect on the oxidative stability of the oil entrapped in the system. It results to be ineffective in affecting the first steps of oxidation but appears a consisting hurdle against the development of secondary oxidation product formation. These results appear interesting in the light of exploitation of organogels to structure liquid oil and thus to product novel health value-added foods.     

On models of fractal networks

A couple of iterative models for the theoretical study of fractal networks whose topologies are generated via iterated function systems is presented: a lumped‐parameter impedor‐oriented one and a two‐port‐network‐oriented one. With the former, the voltage and current patterns give a detailed understanding of the electromagnetic fields' self‐similar distribution throughout the network; on the other hand, model complexity exponentially increases with the prefractal iteration order. The latter ‘black‐box’ model only controls port‐oriented global parameters that are the ones commonly used in the integration of different electronic systems, and its complexity is independent of prefractal order. Sierpinski gasket and carpet topologies are reported as examples. Copyright © 2008 John Wiley & Sons, Ltd.     

Insights into the physicochemical properties of coffee oil

The lipid fraction of roasted coffee is an interesting ingredient that could be used in a large number of food formulations. Coffee oil has peculiar flavouring as well as nutraceutical characteristics. The feasibility of the use of coffee oil as ingredient greatly depends not only on its chemical characteristics but also on its physical properties. The crystallisation and melting properties of the coffee oil extracted from Arabica roasted coffee powder were determined by using synchrotron X‐ray diffraction coupled with differential scanning calorimetry. The fatty acid composition and the flavour profile were also assessed by using GC and GC‐MS analyses, respectively. The main fatty acids found in coffee oil are linoleic and palmitic acid. Significant amounts of stearic and oleic acid are also present. These chemical characteristics are linked to the phase transition behaviour. The crystallisation of coffee oil occurs at 6.5 ± 0.3 °C, independently of the cooling rate applied (from 0.5 to 10 °C/min). A unique crystalline structure was identified: a double chain length (2L) β' structure (55.29 Å). The sole formation of the β' form indicates that this metastable crystal is the only one that one should expect in foods containing coffee oil stored below 7 °C.