Production and analysis of ochratoxin A produced by Aspergillus ochraceus ITEM 5137 in submerged culture

A rapid simple and economical method was described for the determination of ochratoxin A produced by Aspergillusochraceus ITEM 5117 grown in a biofermenter in submerged culture. The ochratoxin A was determinate with RP-HPLC-FLD (reverse phase high performance liquid chromatography) with direct injection in the HPLC apparatus using a C18 column. The mycotoxin was completely resolved by using the mixture acetonitrile, water and acetic acid (49:49:2 v/v) as the mobile phase with a flow rate of 1.0 mL/min. Mean recoveries of ochratoxin A ranged from 95.36% to 103.15%. The limit of detection for ochratoxin A in medium was found to be 1 μg L⁻¹.     

Fast algorithms for nonparametric population modeling of large data sets

Population models are widely applied in biomedical data analysis since they characterize both the average and individual responses of a population of subjects. In the absence of a reliable mechanistic model, one can resort to the Bayesian nonparametric approach that models the individual curves as Gaussian processes. This paper develops an efficient computational scheme for estimating the average and individual curves from large data sets collected in standardized experiments, i.e. with a fixed sampling schedule. It is shown that the overall scheme exhibits a “client-server” architecture. The server is in charge of handling and processing the collective data base of past experiments. The clients ask the server for the information needed to reconstruct the individual curve in a single new experiment. This architecture allows the clients to take advantage of the overall data set without violating possible privacy and confidentiality constraints and with negligible computational effort.     

Preferences for ancient and modern art museums: Visitor experiences and personality characteristics.

This research has two main purposes. The first is to replicate and possibly to extend the results obtained in a previous study, where the authors found that visitors to the ancient art museum conducted their visit with the primary aim of acquiring understanding and knowledge, while modern art museum visitors conducted their visit with an approach that was primarily emotional and pleasure-seeking. The second purpose relates to studies showing that people who prefer abstract art present higher levels on personality traits like “Openness to Experience” and “Sensation Seeking,” compared to people who prefer realistic art. This study investigates these two personality traits for people who favor visiting museums of ancient rather than modern art. Results confirmed previous findings that emotional aspects related to the visit were relevant for modern art museum visitors, while a more cognitive approach based on learning characterized ancient art museum visitors. Concerning personality traits, no difference was found between the two museum groups on the “Openness to Experience” dimension; differences were found on the “Sensation Seeking” trait; modern art museum visitors attained higher scores as compared to ancient art museum visitors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis,characterization and side chains crystallization of comb-like poly(<Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">n</Emphasis>-alkylstyrene)s

A series of comb like poly(p-n-alkylstyrene)s with linear alkyl groups, containing even numbers of carbon atoms from 12 up to 22 were synthesized by radical polymerization and characterized by FTIR, ¹H NMR, TGA, TVA DSC, and WAXS. All polymers were obtained in good yields and were soluble in organic solvents as chloroform, dichloromethane or tetrahydrofuran and insoluble in methanol; they are stable up to temperatures near 300 °C. On the other hand, the alkylic side chains of all series are able to crystallize in a paraffinic phase in which the melting temperature and enthalpy increase with the methylene number of the n-alkyl chain.     

δ-Tocomonoenol: A new vitamin E from kiwi (Actinidia chinensis) fruits

A new vitamin E, δ-tocomonoenol, has been isolated from Actinidia chinensis (kiwi) fruits. The new structure, 2,8-dimethyl-2-(4,8,12-trimethyltridec-11-enyl)chroman-6-ol, has been elucidated on the basis of EIMS, 1D, and 2D NMR spectral data. GC–MS analysis of peels and pulps of kiwi showed that the new compound, together with δ-tocopherol, is mainly present in the fruit peel, whilst α-tocopherol is present in a similar amount in both matrices. The compound was tested for its radical-scavenging and antioxidant capabilities, by measuring its ability to scavenge DPPH (2,2′-diphenyl-1-picrylhydrazyl radical) and anion superoxide radical, and inhibit the formation of methyl linoleate conjugated diene hydroperoxides and TBARS (thiobarbituric acid reactive species).     

Performance and robustness of block constraint preconditioners in finite element coupled consolidation problems

Block constraint preconditioners are a most recent development for the iterative solution to large‐scale, often ill‐conditioned, coupled consolidation problems. A major limitation to their practical use, however, is the somewhat difficult selection of a number of user‐defined parameters (at least 4) in a more or less optimal way. The present paper investigates the robustness of three variants of the block constraint preconditioning in relation to the above parameters. A theoretical analysis of the eigenspectrum of the preconditioned matrix provides relatively simple bounds of the eigenvalues as a function of these parameters. A number of test problems used to validate the theoretical results show that both the mixed constraint preconditioner (MCP) combined with the symmetric quasi‐minimal residual (SQMR) solver and the MCP triangular variant (T‐MCP) combined with the bi‐conjugate gradient stabilized (Bi‐CGSTAB) are efficient and robust tools for the solution to difficult Finite Element‐discretized coupled consolidation problems. Moreover, the practical selection of the user‐defined parameters is relatively easy as a stable behavior is observed for a wide range of fill‐in degree values. The theoretical bounds on the eigenspectrum of the preconditioned matrix may help to suggest the most appropriate parameter combination. Copyright © 2009 John Wiley & Sons, Ltd.     

Computational flowfield analyses of hypersonic problems with reacting boundary layer

A mathematical model able to deal with high temperature gas effects in hypersonic flow fields is presented. In order to assess this model, four typical hypersonic applications are considered. The numerical results are presented and compared with experimental data. The effects of the catalyticity of the materials on the heat fluxes are also highlighted.     

A combined approach for characterisation of fresh and brined vine leaves by X-ray powder diffraction,NMR spectroscopy and direct infusion high resolution mass spectrometry

X-ray powder diffraction was combined, for the first time, with Nuclear Magnetic Resonance spectroscopy and direct infusion mass spectrometry to characterise fresh and brined grape leaves. Covariance analysis of data generated by the three techniques was performed with the aim to correlate information deriving from the solid part with those obtained for soluble metabolites. The results obtained indicate that crystalline components can be correlated to the metabolites contained in the grape leaves, paving the way to the use of X-ray diffraction analysis for food fingerprinting purposes. Moreover it was ascertained that, differently from most of the metabolites present in the fresh vine leaves, linolenic acid (an omega-3-fatty acid) and quercetin-3-O-glucuronide (a polyphenol metabolite) do not undergo sensible degradation during the brining process, which is used as preservative method for the grape leaves.     

Microdroplet-based multiplex PCR on chip to detect foodborne bacteria producing biogenic amines

The development of fast, reliable and culture-independent molecular tools to detect bacteria producing biogenic amines deserves the attention of research and ultimately of the food industry in order to protect consumers' health. Here we present the application of a simple, low-cost, fast and sensitive method to perform microdroplet-based multiplex PCR, directly on a food matrix, for the simultaneous detection of bacterial genes involved in biogenic amine biosynthesis. After inoculating wine with Lactobacillus brevis IOEB 9809, cell lysis and DNA amplification are performed in one single step, without preliminary nucleic acid extraction or purification treatments. The assay is performed in about 30 min, requiring 150 nL of starting sample and it enables the detection of down to 15 bacterial cells. With respect to traditional culture techniques, the speed, the simplicity and the cheapness of this procedure allow an effective monitoring of microbial cells during food-making and processing.