Automatic temperature controller for multielement array hyperthermia systems

This paper concerns the optimization and performance analysis of an automatic control algorithm for managing power output of large multielement array hyperthermia applicators. Simulation and corresponding measurement of controller performance in a solid tissue equivalent phantom model is utilized for analysis of controller response to dynamically varying thermal load conditions that simulate clinical treatments. The analysis leads to an optimum controller which demonstrates the ability to achieve a uniform and stable temperature profile over a large surface area regardless of surrounding thermal load. This paper presents several advancements to the performance of a previously published control routine, including: 1) simplified simulation techniques for thorough characterization of controller performance; 2) an optimization procedure leading to an improved hybrid control algorithm for maintaining optimal performance during periods of both "rising" and "steady-state" temperature; 3) performance analysis of a control algorithm tailored for large area hyperthermia treatments with a mulitelement array applicator. The optimized hybrid controller is applied to the conformal microwave array (CMA) hyperthermia system previously developed for heating large area surface disease such as diffuse chestwall recurrence of breast carcinoma, and shown to produce stable, uniform temperatures under the multielement array applicator for all thermal load conditions.     

Crystals and crystallinity in polymeric materials

A new view of the concepts of crystallinity and crystals in synthetic macromolecules is discussed. In polymeric materials, crystallinity may be present with the concomitant occurrence of large amounts of structural disorder and in the absence of true three-dimensional long-range order. The structures of semicrystalline polymeric materials are discussed in terms of idealized limit models of crystals, where long-range order may be achieved for structural features that are not necessarily coincident with single atoms and are not necessarily point-centered. Typical examples of non-point-centered structural features are the straight lines corresponding to the chain axes of polymer molecules. This view explains the unusual ability of polymers to crystallize even in the presence of a high degree of structural disorder.     

Development of antiviral fusion inhibitors: short modified peptides derived from the transmembrane glycoprotein of feline immunodeficiency virus

Feline immunodeficiency virus (FIV) is a naturally occurring pathogen that causes an AIDS-like syndrome in domestic cats and is a valuable model system by which criteria for antiviral vaccines and drugs development can be tested. The cell-entry step of the lentivirus life cycle is regarded as a promising target for the development of new generation inhibitors. We have previously described potent in vitro anti-FIV activity associated with a synthetic octapeptide, termed C8 (Ac-Trp-Glu-Asp-Trp-Val-Gly-Trp-Ile-NH2), containing the Trp-rich motif of FIV transmembrane glycoprotein, which shares a common structural framework with the corresponding molecule of HIV and appears to play a similar role in cell entry. In this report, in an attempt to develop simpler potential fusion inhibitors to be tested in vivo, we describe further studies focused on synthetic peptide analogues of C8. Since C8 inhibitory activity is dependent upon the Trp motif, we systematically replaced these residues with bulky and/or aromatic natural and unnatural amino acids, in order to develop a rational structure-activity relationship. Furthermore, the amino acids located between the Trp residues, which are not crucial for inhibitory activity, were replaced by simple alkyl spacers of appropriate length. Design, NMR structural analysis, in vitro anti-FIV activity in lymphoid cell cultures, and serum stability of these new analogues are reported. The final results indicate that a simpler hexapeptide (Ac-Nal2-Ape-Nal2-Ape-Nal2-Ile-NH2; Nal2 = 3-naphthalen-2-yl-L-alanine, Ape = 5-aminopentanoic acid), almost entirely made up of unnatural amino acid residues, has markedly increased enzymatic stability, while maintaining strong antiviral potency in vitro.     

A dynamic investigation of cognitive dedifferentiation with control for retest: Evidence from the Swiss Interdisciplinary Longitudinal Study on the Oldest Old.

Empirical examinations of the hypothesis of dedifferentiation of cognitive abilities in old and very old age (a) do not account for possible retest effects, which consequently may yield biased estimates of age effects, and (b) focus on time-independent relations (e.g., number of latent constructs, correlations between latent or measured variables). The authors applied a structural equation model with statistical control for retest effects to investigate the dynamic relations between a marker of perceptual speed (cross out) and a marker of verbal fluency (category-fruits). Longitudinal data are from 5 waves of the Swiss Interdisciplinary Longitudinal Study on the Oldest Old (N = 377, baseline age range = 79.5- 84.5 years). The authors found that, independently of retest effects, performance on the cross-out task affected changes in performance on the category task while the opposite did not hold true. This analytical technique could be applied to various markers of broad fluid-mechanic and broad crystallized-pragmatic components of cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pictures from Mongolia. Extracting the Top Elements from a Partially Ordered Set

You are back from that very long, marvellous journey. You have a thousand pictures, but your friends and relatives will stand just a few dozens. Choosing is a painful process, in particular when you cannot decide between the silent vastness of that desert and the idyllic picture of that tranquil, majestic lake. We are going to help. A preliminary version of this paper appeared in [1].     

Towards a technological ripening index for olive oil fruits

BACKGROUND: The aim of this work was to study the evolution of sugar and oil contents in Frantoio cultivar olives during ripening in order to propose a technological ripening index for olive oil fruits. Olive fruits were picked at nine different farms once a week from the beginning of September to the beginning of December during three crop seasons. RESULTS: As a result of the biochemical phenomenon of oil formation in olive fruits, sugar concentration during ripening was shown to follow a sigmoidal decrease, which recurred periodically in different microclimates over years. This trend resulted to be the cause of an opposite sigmoidal increase in oil content. Experimental data for sugar and oil contents were also statistically related by significant linear relationships. In addition, it was observed that reaching a minimum environmental temperature of ⩽10 °C resulted in a definite minimum asymptotic value for sugars. CONCLUSION: Sugar concentration can be proposed as an accurate, reproducible index for technological ripening of olive oil fruits by the following prediction function: proper ripening degree of olives corresponds to achievement of a constant minimum value for sugar content and, consequently, a constant maximum value for oil content, associated with reduced risk of fermentation activities of olive paste. Copyright © 2009 Society of Chemical Industry     

Fenhexamid residues in grapes and wine

The behaviour of the fungicide, fenhexamid, on grapes, and during wine-making, as well as its effect on the microflora of alcoholic and malolactic fermentation has been studied. After treatment, the residue on grapes decreased rapidly to one-third of the initial level after the first week, while it remained constant during the following two weeks. At harvest, in the wine obtained by vinification without skins, the fungicide residue decreased on average by 49% , while in the wine obtained by vinification with skins, the decrease was on average 62% . The presence of this fungicide on grapes and in the wine did not affect alcoholic and malolactic fermentation, nor did fermentation cause any degradation of the fungicide. A simple and rapid gas chromatograhic method (GC-NPD) for the determination of fenhexamid residues in grapes, must and wine is described.     

Activation of porous Ni cathodes towards hydrogen evolution by electrodeposition of Ir nuclei

Porous Ni electrodes were modified by electrodeposition of Ir nuclei from H₂IrCl₆ solutions at 70 °C, with the aim of activating them towards the hydrogen evolution reaction and comparing their performance with those of porous Ni electrodes activated by spontaneous deposition of noble metals (Ir and Ru). The current efficiency of Ir deposition was found to be very low (1% or lower, decreasing upon increasing deposition current density). Ir deposits characterised by SEM-EDX and XRD consisted of nanocrystals decorating the Ni dendrites forming the porous layers. Ir electrodeposition led to a strong activation of the hydrogen evolution reaction from aqueous 1 M NaOH. The electrocatalytic activity of the cathodes was independent of the Ir deposition charge above the minimum explored value of 1  C cm^?2. This charge is estimated to correspond to the deposition of ca. 2.5 10^?8 Ir moles cm^?2. The kinetic parameters for hydrogen evolution were similar for porous Ni electrodes modified by either spontaneous deposition (studied in a previous work) or electrodeposition of Ir.     

Mechatronic analysis of a complex transmission chain for performance optimization in a machine tool

Mechatronic models of complex mechanical systems allow to assemble reliable simulators, which can be used to test alternative choices made at component level. When the complexity of the system is significant, however, it is neither easy to model the interactions among different elements, nor immediate to identify the components responsible for a possible loss of performance of the system. Based on a detailed linear model of a complex transmission chain used within a large size machine tool, this paper contributes presenting a methodology, supported by modal analysis, to quantify the sensitivity of each vibration mode to the stiffness of each component. A nonlinear simulator of the transmission has been derived, too, and its remarkable performance in reproducing the experiments is demonstrated. Insight on the role of Coulomb friction is also provided, together with a practical way to split the overall friction between motor and load sides.