Rapid and Simultaneous Analysis of Xanthines and Polyphenols as Bitter Taste Markers in Bakery Products by FT-NIR Spectroscopy

The food industry has a direct interest into bitter-tasting substances either for the identification of negative off-flavors or for the monitoring of a desired organoleptic quality. A rapid technique, based on Fourier transform-near infrared (FT-NIR) spectroscopy and able to detect taste molecular markers in bakery commodities, was developed, focusing the attention on biscuits category. Xanthines (caffeine, theobromine, and theophylline) and polyphenols (catechins and epicathechins), considered as mainly responsible for the bitter-taste of coffee\cocoa\chocolate based products, were firstly checked using a confirmatory liquid chromatography (LC)-ESI\mass spectrometry (MS)-MS procedure after hot methanol–water extraction. Correspondent data were used for the calibration of the FT-NIR through PLS regression. Values of the standard errors of prediction (lower than 10 %) were comparable to the values of the standard errors of cross-validation. Coefficients of determination indicated a good predictive power in the calibration model (R ² xanthines?=?0.97, R ² polyphenols?=?0.96) and a satisfying discriminating power among different contents in the validation models (R ² xanthines?=?0.96, R ² polyphenols?=?0.96). A testing phase on the generated model was executed by a comparison of LC-MS and sensory panel data with FT-NIR responses recorded on unknown biscuits: differences between found and predicted levels were generally below 5 % and the best predictability was achievable in chocolate-based biscuits. This methodology is able to work directly on solid products, has the potential to be expanded on other categories of gustative molecular markers (like sugars) and can be conceived as applicable for a routine control of a standardized bitter taste quality in a real industrial production.     

Stubborn Sets for Real-Time Petri Nets

The stubborn-set method attempts to reduce the number of states that must be explicitly enumerated during reachability analysis of a concurrent system, while preserving crucial concurrency properties in the reduced state space. Here we extend the method to the analysis of certain timed models. We also prove that timing properties of interest, such as minimum and maximum delays between events, are preserved in the reduced model. Finally, we report on some experimental results that we have obtained with our extension. These results show that real-time stubborn sets can often provide significant reductions in state space size.     

Synchronization Algebras with Mobility for Graph Transformations

We propose a generalization of synchronization algebras that allows to deal with mobility and local resource handling. We show how it can be used to model communication primitives for distributed and mobile computations, such as the ones used in the global computing area. We propose a graph transformation formalism in the Synchronized Hyperedge Replacement approach which is parametric w.r.t. the synchronization algebra and thus allows to model complex systems based on the chosen communication primitives. We thus unify different models described in the literature and we allow to easily define new ones. We present various examples and a case study on Fusion Calculus, showing how different semantics for it can be derived using different synchronization algebras.     

Compositional SOS and beyond: a coalgebraic view of open systems

In this paper we address the issue of providing a structured coalgebra presentation of transition systems with algebraic structure on states determined by an equational specification Γ. More precisely, we aim at representing such systems as coalgebras for an endofunctor on the category of Γ-algebras. The systems we consider are specified by using arbitrary SOS rules, which in general do not guarantee that bisimilarity is a congruence. We first show that the structured coalgebra representation works only for systems where transitions out of complex states can˜be derived from transitions out of corresponding component states. This decomposition property of transitions indeed ensures that bisimilarity is a congruence. For a system not satisfying this requirement, next we propose a closure construction which adds context transitions, i.e., transitions that spontaneously embed a state into a bigger context or vice versa. The notion of bisimulation for the enriched system coincides with the notion of dynamic bisimilarity for the original one, i.e., with the coarsest bisimulation which is a congruence. This is sufficient to ensure that the structured coalgebra representation works for the systems obtained as result of the closure construction.     

Dynamics of 3-D co-rotational beams

This paper discusses different types of implicit time integration algorithms for the dynamics of spatial beams. The algorithms are based on a form of co-rotational technique which is external to the element. Both end-point and mid-point formulations are presented. The latter can be considered as an `approximately energy conserving algorithm'. A new method is described for introducing numerical damping. Finally some numerical examples are presented in order to illustrate the differences in performance of the different integration schemes.     

Anwendung eines elektronischen Rechners für Rundstahlkalibrierungen

Unterteilung der Kalibrierung in drei Kaliberfolgen: Vorwalzung mit geringer Streckung, Kaliberfolge mit großer Streckung und Fertigwalzung. Untersuchung der verschiedenen Kaliberfolgen und Konstruktion der Kaliber. Anwendung eines Rechners.     

The nonlinear response of unsymmetric multilayered plates using smeared laminate and layerwise models

A continually growing interest in the response of unsymmetric multilayered plates is apparent. Analyses were recently completed addressing the load-deflection behaviour of these plate geometries. The characteristic feature of the analyses is the use of nonlinear strain-displacement relations, even at low loading levels, in reaction to the large-deflection effect enhanced by the bending-extension and twisting-shearing coupling. Approaches where use is made of Higher Order Shear Deformation Theories (HSDT) for predicting global quantities, such as deflections and critical loads, are not found in the open literature. Such modelling approaches, in particular those of the layerwise type, are reserved to predict distributions across the thickness. Thus, a further assessment of the influence of the transverse shear effect on global quantities should be required. To give some preliminary contributions on this subject, the load-deflection behaviour of a [90₄/0₄] cross-ply plate with pinned edges, subjected to cylindrical bending under uniform transverse pressure, is investigated. Use is made of the Layerwise Higher Order Shear Deformation Layerwise Theory (RHSD) to serve this purpose. From the numerical results presented, the influence of modelling is enhanced or reduced, depending on the sign of loading. It is concluded that, depending on the loading, boundary conditions and lay-up, higher-order approaches can be used for predicting global quantities in unsymmetric multilayered plates. In order to investigate stability, nonlinear equations are developed where critical points are located under boundary and combined loading conditions which vary during perturbation.     

Fabrication of a Macroporous Microwell Array for Surface‐Enhanced Raman Scattering

Here, a colloidal templating procedure for generating high‐density arrays of gold macroporous microwells, which act as discrete sites for surface‐enhanced Raman scattering (SERS), is reported. Development of such a novel array with discrete macroporous sites requires multiple fabrication steps. First, selective wet‐chemical etching of the distal face of a coherent optical fiber bundle produces a microwell array. The microwells are then selectively filled with a macroporous structure by electroless template synthesis using self‐assembled nanospheres. The fabricated arrays are structured at both the micrometer and nanometer scale on etched imaging bundles. Confocal Raman microscopy is used to detect a benzenethiol monolayer adsorbed on the macroporous gold and to map the spatial distribution of the SERS signal. The Raman enhancement factor of the modified wells is investigated and an average enhancement factor of 4 × 10⁴ is measured. This demonstrates that such nanostructured wells can enhance the local electromagnetic field and lead to a platform of ordered SERS‐active micrometer‐sized spots defined by the initial shape of the etched optical fibers. Since the fabrication steps keep the initial architecture of the optical fiber bundle, such ordered SERS‐active platforms fabricated onto an imaging waveguide open new applications in remote SERS imaging, plasmonic devices, and integrated electro‐optical sensor arrays.