On fumonisin incidence in monoculture maize under no‐till,conventional tillage and two nitrogen fertilisation levels

BACKGROUND: Fusarium ear rot and fumonisin contamination are serious problems for maize growers. The lack of maize genotypes highly resistant to fumonisin contamination emphasises the need for management strategies to prevent contamination by this mycotoxin. There are conflicting reports regarding no‐till and nitrogen (N) fertilisation practices in relation to the incidence of fumonisins. In this study the effect of no‐till compared with conventional tillage and of N fertilisation rates on fumonisin occurrence was investigated over three years in Northern Italy. RESULTS: The average contamination of grain by fumonisins B₁ and B₂ over the three years was significantly different, with a lower value in 2000 (516 µg kg^?1) than in the other years (5846 and 3269 µg kg^?1 in 2001 and 2002 respectively). Conventional tillage and no‐till treatments had no significant effect on the incidence of fumonisins. This finding suggests that above‐ground residues infected by Fusarium would not lead to an increase in fumonisin incidence. However, N fertilisation significantly increased fumonisin levels, by 99 and 70% in 2000 and 2001 respectively. CONCLUSION: Maize monoculture does not show a cumulative effect on the occurrence of fumonisins, while high rates of N fertiliser consistently result in elevated fumonisin levels. Both these effects can be influenced by annual meteorological fluctuations. Copyright © 2008 Society of Chemical Industry     

Purification and characterization of a cationic peroxidase from artichoke leaves

Peroxidases are part of a large group of enzymes associated with cell wall biosynthesis, response to injury, disease, resistance and wound repair. Among peroxidase isoenzymes, a soluble cationic peroxidase (ALSP), not yet described, has been partially purified and characterized from artichoke leaves. The enzyme was shown to be a glycoprotein with a molecular weight of 51 000 and an isoelectric point of 9. The substrate specificity of the ALSP is characteristic of class III (guaiacol‐type) peroxidases. The ALSP was partially purified by ammonium sulfate precipitation, gel filtration, affinity chromatography, anionic exchange high‐performance liquid chromatography and isoelectrofocusing. The increase in specific activity was 43 times compared to the crude extract as estimated by the guaiacol assay. Three ALSP fragments were sequenced by tandem mass spectrometry de novo sequencing method. Copyright © 2007 Society of Chemical Industry     

Multiple real-pole equal-ripple rational (MRPER) approximation for lowpass RC-active filters

A new class of lowpass rational transfer functions is defined, with equal-ripple behaviour both in the passband and in the stopband. The proposed functions have a multiple real pole, which allows the realization of lowpass RC-active filters by cascading more (than one) 3rd-order blocks. These new functions, called multiple real-pole equal-ripple rational (MRPER), improve the attenuation performance with respect to a classical solution employing the same number of 2nd-order blocks and hence may allow a reduction in the required number of active elements and, eventually, in power consumption and in noise-to-signal ratio. However, even if the number of active blocks cannot be reduced, the better attenuation performance, which results, allows component tolerances to relax.     

Multitarget‐Directed Tricyclic Pyridazinones as G Protein‐Coupled Receptor Ligands and Cholinesterase Inhibitors

By following a multitarget ligand design approach, a library of 47 compounds was prepared, and they were tested as binders of selected G protein‐coupled receptors (GPCRs) and inhibitors of acetyl and/or butyryl cholinesterase. The newly designed ligands feature pyridazinone‐based tricyclic scaffolds connected through alkyl chains of variable length to proper amine moieties (e.g., substituted piperazines or piperidines) for GPCR and cholinesterase (ChE) molecular recognition. The compounds were tested at three different GPCRs, namely serotoninergic 5‐HT_1A, adrenergic α_1A, and dopaminergic D₂ receptors. Our main goal was the discovery of compounds that exhibit, in addition to ChE inhibition, antagonist activity at 5‐HT_1A because of its involvement in neuronal deficits typical of Alzheimer’s and other neurodegenerative diseases. Ligands with nanomolar affinity for the tested GPCRs were discovered, but most of them behaved as dual antagonists of α_1A and 5‐HT_1A receptors. Nevertheless, several compounds displaying this GPCR affinity profile also showed moderate to good inhibition of AChE and BChE, thus deserving further investigations to exploit the therapeutic potential of such unusual biological profiles.     

Mixed-Initiative Issues in an Agent-Based Meeting Scheduler

This paper concerns mixed-initiative interaction between users and agents. After classifying agents according to their task and their interactivity with the user, the critical aspects of delegation-based interaction are outlined. Then MASMA, an agent system for distributed meeting scheduling, is described, and the solutions developed to control interaction are explained in detail. The issues addressed concern: the agent capability of adapting its behavior to the user it is supporting; the solution adopted to control the shift of initiative between personal agents, their users and other agents in the environment; the availability of features, e.g. the inspection mechanism, that endow the user with a further level of control to enhance his sense of trust in the agent.     

TG68, a Novel Thyroid Hormone Receptor-β Agonist for the Treatment of NAFLD

Activation of thyroid hormone receptor β (THRβ) has shown beneficial effects on metabolic alterations, including non-alcoholic fatty liver disease (NAFLD). Here, we investigated the effect of TG68, a novel THRβ agonist, on fatty liver accumulation and liver injury in mice fed a high-fat diet (HFD). C57BL/6 mice fed HFD for 17 or 18 weeks, a time when all mice developed massive steatohepatitis, were then given TG68 at a dose of 9.35 or 2.8 mg/kg for 2 or 3 weeks, respectively. As a reference compound, the same treatment was adopted using equimolar doses of MGL-3196, a selective THRβ agonist currently in clinical phase III. The results showed that treatment with TG68 led to a reduction in liver weight, hepatic steatosis, serum transaminases, and circulating triglycerides. qRT-PCR analyses demonstrated activation of THRβ, as confirmed by increased mRNA levels of Deiodinase-1 and Malic enzyme-1, and changes in lipid metabolism, as revealed by increased expression of Acyl-CoA Oxidase-1 and Carnitine palmitoyltransferase-1. The present results showed that this novel THRβ agonist exerts an anti-steatogenic effect coupled with amelioration of liver injury in the absence of extra-hepatic side effects, suggesting that TG68 may represent a useful tool for the treatment of NAFLD.     

Effect of aw and CO2 level on Aspergillus flavus growth and aflatoxin production in high moisture maize post-harvest

The potential for using modified atmospheres of 25-75% CO2 (balanced with N2) and water activity (aw, 0.95, 0.92) to control Aspergillus flavus development and aflatoxin B1 production has been evaluated (a) on synthetic medium and (b) on maize grain during storage for up to 21 days at 25 degrees C. On agar medium up to 75% CO2 at both 0.95 and 0.92 aw significant inhibition of growth was obtained (P<0.05). In stored grain inoculated with spores of A. flavus there was significantly higher populations of the species at 0.95 aw than 0.92 aw. Up to 75% CO2 resulted in an inhibition of the populations of A. flavus isolated from the grain. Contrasting aflatoxin B1 production was obtained on agar and in stored maize grain. On agar, greatest amounts were produced at 0.92 aw, while more was produced at 0.95 aw on maize grain. Overall, the efficacy of controlled atmospheres x aw showed that treatment with 25% CO2 could be sufficient to efficiently reduce A. flavus development but at least 50% CO2 was required to obtain a significant reduction of aflatoxin synthesis.     

Aflatoxins and ochratoxin A in dried chestnuts and chestnut flour produced in Italy

The occurrence of aflatoxins and ochratoxin A in chestnut products made in Italy was surveyed. Thirty-seven samples of chestnut flour and fourteen of dried chestnuts were collected from retail outlets located in northern Italy. After extraction and purification through an immunoaffinity column, aflatoxins and ochratoxin A were analysed using both HPLC-FLD and HPLC-MS/MS. The mycotoxin contamination found in this survey was widespread and remarkable. As regards aflatoxins, the incidence of aflatoxin B₁ was 62.2 and 21.4% in chestnut flour and dried chestnuts, respectively; in the same products, the percentage of samples exceeding the value of 2.0 μg kg⁻¹ for aflatoxin B₁ (maximum limit fixed by EC Regulation 165/2010 in dried fruits) was 24.3% and 7.1%. A widespread and high incidence of AFG₁ was also found (40.5%). The maximum values for aflatoxin B₁ and total aflatoxins were 67.88 and 188.78 μg kg⁻¹, respectively (chestnut flour sample). Ochratoxin A occurred in all samples, showing very high values (mean 12.38 and 13.63 μg kg⁻¹ for chestnut flour and dried chestnuts, respectively); the percentages of samples exceeding the limit of 10 μg kg⁻¹ (EU limits for dried vine fruit) were 64.9 and 42.8% for chestnut flour and dried chestnuts, respectively. The maximum value was 65.84 μg kg⁻¹ (dried chestnut sample).     

Electrothermal stability of uniform arrays of one‐port elements

Power electronic elements are often built employing arrays of devices designed to evenly share high currents over a large number of single devices. In some situations, mismatch in current sharing can occur causing temperature differences between elements of the array. These differences can trigger electrothermal instability phenomena and even device destruction. In this paper, we consider the electrothermal dynamic behavior of arrays composed of identical one‐port elements. We first introduce a simplified model of the thermal paths and of the elements composing the array that allows the analysis of the behavior of the electrothermal system. Then, we investigate from a mathematical standpoint dynamic effects governing current sharing and possible situations causing hot spots with consequent device destruction. These results are compared with simulations of detailed non‐linear models confirming predictions given by the simplified model. Copyright © 2008 John Wiley & Sons, Ltd.     

Mesenchymal Stem Cells Increase Neo-Angiogenesis and Albumin Production in a Liver Tissue-Engineered Engraftment

The construction of a three-dimensional (3D) liver tissue is limited by many factors; one of them is the lack of vascularization inside the tissue-engineered construct. An engineered liver pocket-scaffold able to increase neo-angiogenesis in vivo could be a solution to overcome these limitations. In this work, a hyaluronan (HA)-based scaffold enriched with human mesenchymal stem cells (hMSCs) and rat hepatocytes was pre-conditioned in a bioreactor system, then implanted into the liver of rats. Angiogenesis and hepatocyte metabolic functions were monitored. The formation of a de novo vascular network within the HA-based scaffold, as well as an improvement in albumin production by the implanted hepatocytes, were detected. The presence of hMSCs in the HA-scaffold increased the concentration of growth factors promoting angiogenesis inside the graft. This event ensured a high blood vessel density, coupled with a support to metabolic functions of hepatocytes. All together, these results highlight the important role played by stem cells in liver tissue-engineered engraftment.