Polyphenol compounds in artichoke plant tissues and varieties

Polyphenol compounds, particularly caffeoylquinic acids and flavonoids, were measured in different tissues and developmental stages of 6 artichoke varietal types diffused in the Mediterranean region. Flower heads were subdivided into external, intermediate, internal bracts, and receptacle, while leaves were collected at the vegetative and productive stages. The main polyphenols detected were chlorogenic acid, cynarin, luteolin 7-O-rutinoside, and luteolin 7-O-glucoside. "Violet de Provence" artichoke proved to retain the highest content of total phenols. Single polyphenols accumulated preferentially in specific parts of capitula. In leaves, most polyphenols were detected in the productive stage of the plant. Altogether, results provide useful indications for the promotion of artichoke as nutraceutical food and for the extraction of health-promoting substances in particular tissues/stages of the artichoke plant. PRACTICAL APPLICATION: We describe the content of phenolic compounds in various artichoke tissues, developmental stages, and varieties. Results indicate that artichoke leaves represent an important source of these health-promoting compounds, also useful for phytopharmaceutical applications. A wider utilization of specific artichoke types should be strongly encouraged not only as a food for the fresh market, as they are now used, but also for the pharmaceutical industry, since the content of phenolic compounds is abundant both in the heads and in the leaves.     

Parametric macromodeling based on amplitude and frequency scaled systems with guaranteed passivity

We propose a novel parametric macromodeling method for systems described by scattering parameters, which depend on multiple design variables such as geometrical layout or substrate features. It is able to build accurate multivariate macromodels that are stable and passive over the entire design space. Poles and residues are parameterized indirectly. The proposed method is based on an efficient and reliable combination of rational identification, a procedure to find amplitude and frequency scaling system coefficients and positive interpolation schemes. Pertinent numerical examples validate the proposed parametric macromodeling technique. Copyright © 2011 John Wiley & Sons, Ltd.     

Advanced receiver design for satellite‐based automatic identification system signal detection

This paper describes an innovative receiver architecture for the satellite‐based automatic identification system. The receiver performance has been fully validated in the presence of the typical satellite channel characteristics. In particular, it is shown that the devised receiver provides an excellent performance against the noise, as well as a large resilience against message collisions, Doppler shift, and delay spread. Copyright © 2012 John Wiley & Sons, Ltd.     

Application of ESI and MALDI‐TOF MS for triacylglycerols analysis in edible oils

Triacylglycerols (TAG) are the most important group of compounds present in vegetable oils. These biomolecules, determining the physical, chemical and nutritional properties of the oils, are considered to be good fingerprints for quality and authenticity control. Therefore, TAGs characterization is a very important task in edible oil field, which has been undertaken by different analytical methods. The analysis of vegetable oils is still dominated by classic determinations, which are however laborious and time‐consuming and cannot be used routinely. More recently, advances in MS instrumentations coupled with online separation techniques and data processing have contributed to great expansion of MS in oil study, allowing the development of innovative analytical approaches that exhibit higher sensitivity, accuracy and rapidity in vegetable oils investigations. In the present contribution, a review of the most relevant applications of novel mass spectrometric techniques, such as ESI and MALDI, both alone and hyphenated with HPLC, used for analysis of the complex TAGs mixture of edible oils is illustrated.     

Visible spectroelectrochemical characterization of Geobacter sulfurreducens biofilms on optically transparent indium tin oxide electrode

We report visible spectroelectrochemical (SEC) characterization of cytochrome c₅₅₂ (cyt c₅₅₂) in viable Geobacter sulfurreducens biofilms on tin-doped indium oxide (ITO) electrodes poised at 0.24 V vs. SHE. G. sulfurreducens biofilms were grown in minimal medium with acetate as electron donor (turnover conditions), followed by 24 h incubation in electron donor-depleted medium (non-turnover conditions). The electronic absorption spectra of G. sulfurreducens biofilms showed the lowest energy absorption band in the reduced state at 552 nm, which indicated excess of cyt c₅₅₂ in the biofilm. The spectra under non-turnover conditions displayed gradual reduction of the cyt c₅₅₂, following the step-wise decrease of electrode potential from 0.0 V to −0.6 V vs. standard calomel electrode (SCE). The spectral changes were fully reversible in both positive and negative direction of the scan potential, with average midpoint potential value of −0.42 V vs. SCE. Confocal microscopy analysis revealed that the thickness of biofilms under turnover conditions and non-turnover conditions was approximately 35 and 3.5 μm, respectively. This is the first study to observe the reversible redox conversion of cyt c₅₅₂ in viable G. sulfurreducens biofilms.     

Developing pyrrole-derived antimycobacterial agents: a rational lead optimization approach

Tuberculosis (TB) represents a never-ending challenge toward which research efforts are needed. Drug resistance is the key problem that scientists in the field need to fight. The development of new drugs endowed with novel modes of action against different biological targets is of extreme importance; these new agents should also exhibit lower toxicity compared with the anti-TB drugs currently available. Furthermore, new drugs should be inexpensive since most of the TB-infected population lives in developing nations. In the last few years, numerous researchers have focused their attention on TB, leading to the discovery of some interesting compounds. Among these, the pyrrole-derived compounds we developed can be considered very promising antimycobacterial agents. Aided by molecular modeling studies, we synthesized numerous compounds characterized by the same 1,5-diarylpyrrole scaffold and elucidated very interesting antitubercular/antimycobacterial properties. Some compounds identified are extremely promising and represent a step towards the design of novel lead structures in the fight against TB. Our efforts to this end are reviewed here.     

Semi-dynamic breadth-first search in digraphs

In this paper we propose dynamic algorithms for maintaining a breadth-first search tree from a given source vertex of a directed graph G in either an incremental or a decremental setting. During a sequence of q edge insertions or a sequence of q edge deletions the total time required is O(m·min{q,n}), where n is the number of vertices of G, and m is the final number of edges of G in the case of insertions or the initial number of edges of G in the case of deletions. This gives O(n) amortized time for each operation if the sequence has length Ω(m). Our algorithms require O(n+m) space. These are the first results in the literature concerning the dynamic maintenance of a breadth-first search tree for directed graphs. As a straightforward application of such algorithms we can maintain a shortest path tree for a directed graph in the case of unit edge weights within the same time bounds. In this case distance queries can be answered in constant time, while shortest path queries can be answered in time linear in the length of the retrieved path.     

Novel Data on the Polyphenol Composition of Italian Ancient Apple Cultivars

The pulp polyphenol composition of some Italian ancient apple cultivars, Dominici, Giachetta, Grigia di Torriana, Pom d'Aram, Ronzè, and Ros Borsetta, was studied in comparison with a Golden Delicious commercial variety, over a three-year period. Polyphenols were analyzed by liquid chromatography coupled with diode array and mass spectrometer detectors. The results showed that ancient varieties, such as Grigia di Torriana, Ros Borsetta, and Giachetta, constitute good sources of polyphenols, even without the peel. It was demonstrated that some representative apple phenolics, such as chlorogenic acid and phloridzin, were clearly affected by the harvesting year, whereas others, such as catechins and procyanidins, did not.     

Efficiency evaluation of a C Magnetic Resonance birdcage coil: Theory and comparison of four methods

Radiofrequency coils in Magnetic Resonance systems are used to produce a homogeneous B₁ field for exciting the nuclei and to pick up the signals emitted by the nuclei with high signal-to-noise ratio. Accordingly, coil performance affects strongly the quality of the obtained data and images.