Simple Semi-Analytical Expression of the Lightning Base Current in the FrequencyDomain

A simple procedure to express the lightning base current in the frequency domain is presented. The formula, based on a piecewise approximation of the lightning base current in time domain, allows obtaining an expression in the frequency domain in terms of elementary functions. The presented procedure is fast and general, since it can be used with any current waveshape

Activity of synthetic and natural compounds for phytoplasma control

A sustainable and rational procedure to evaluate the activity of synthetic and natural substances towards phytoplasma agents of important tree diseases was developed with the aim of finding new strategies of control. The method of testing is based on 1) the utilization of Catharanthus roseus; 2) the artificial infection of periwinkles with two phytoplasma strains; 3) scion dipping, selected as the most suitable method of applying the substances. A series of natural and synthetic compounds were chosen among a) new agrochemical entries, registered as plant-resistance inducers; b) secondary metabolites of fungal and plant origin; c) new and known biologically active substances never tested before for their antiphytoplasmal properties. The activity of this series of compounds on healthy and phytoplasma-infected periwinkles was evaluated on the basis of several parameters: phytotoxicity, evolution of symptoms and microscope observations. The in-volvement of the third component in the triangular interaction between phytoplasma, plant and compound is discussed

a comparison between analytical solutions for lightning induced voltages calculation

An exact closed form solution for the calculation of lightning-induced voltages on overhead lines has been recently proposed by A. Andreotti et al. (2012). Predictions of this exact formulation are compared here to those based on approximate analytical solutions proposed in the literature. DOI: http://dx.doi.org/10.5755/j01.eee.20.5.296

Effetto del genotipo e del trattamento antipiralide sulla contaminazione da specie afferenti al clade Gibberella fujikuroi in mais coltivato in Lombardia

Fusarium ear rot (FER) of maize is caused by Fusarium species belonging to Gibberella fujikuroi species complex (GFC) well known as fumonisin (FUM) producers. European corn borer (ECB), the most common maize pest in northern Italy, favors the infection of maize by GFC strains. Since ECB control is not completely effective in lowering fumonisin contamination, additional preventive means, such as increased maize resistance, are required in order to assure a more effective protection. Flavonoids in maize pericarp seem to be able to reduce the fumonisin accumulation. The goal of this study was to assess the effect of flavonoids associated with insecticides on ECB and FER rating under field conditions in Lombardy. Two maize hybrids were sown in 2011 and 2012, one hybrid characterized by the presence of flavonoids in pericarp and the other without pigmentation. The ECB damage incidence, frequency and severity of FER, together with the incidence of GFC strains and FUM in kernels, were assessed in each genotype. In 2012, the ECB control associated with flavonoids presence reduced all the measured parameters except FUM contamination. FUM contamination seemed to be more influenced by the local GFC population and the environment rather than pesticides and pericarp pigmentation

Cladosporol A stimulates G1-phase arrest of the cell cycle by up-regulation of p21waf1/cip1 expression in human colon carcinoma HT-29 cells

Cladosporols, purified and characterized as secondary metabolites from Cladosporium tenuissimum, display an antifungal activity. In this study, we tested the antiproliferative properties of cladosporol A, the main isoform of this metabolite family, against human cancer cell lines. By assessing cell viability, we found that cladosporol A inhibits the growth of various human colon cancers derived cell lines (HT-29, SW480, and CaCo-2) in a time- and concentrationdependent manner, specifically of HT-29 cells. The reduced cell proliferation was due to a G1-phase arrest, as assessed by fluorescence activated cell sorting analysis on synchronized HT-29 cells, and was associated with an early and robust over-expression of p21waf1/cip1, the well-known cyclin-dependent kinases inhibitor. This suggests that the drug may play a role in the control of cancer cell proliferation. Consistently, cyclin D1, cyclin E, CDK2, and CDK4 proteins were reduced and histone H1-associated CDK2 kinase activity inhibited. In addition to p21waf1/cip1, exposure to 20 mM cladosporol A caused a simultaneous increase of pERK and pJNK, suggesting that this drug activates a circuit that integrates cell cycle regulation and the signaling pathways both involved in the inhibition of cell proliferation. Finally, we showed that the increase of p21waf1/cip1 expression was generated by a Sp1-dependent p53-independent stimulation of its gene transcription as mutagenesis of the Sp1 binding sites located in the p21 proximal promoter abolished induction. To our knowledge, this is the first report showing that cladosporol A inhibits colon cancer cell proliferation by modulating p21waf1/cip1 expression

Trialkylammonium salt degradation: implications for methylation and cross-coupling

Trialkylammonium (most notably N,N,N-trimethylanilinium) salts are known to display dual reactivity through both the aryl group and the N-methyl groups. These salts have thus been widely applied in cross-coupling, aryl etherification, fluorine radiolabelling, phase-transfer catalysis, supramolecular recognition, polymer design, and (more recently) methylation. However, their application as electrophilic methylating reagents remains somewhat underexplored, and an understanding of their arylation versus methylation reactivities is lacking. This study presents a mechanistic degradation analysis of N,N,N-trimethylanilinium salts and highlights the implications for synthetic applications of this important class of salts. Kinetic degradation studies, in both solid and solution phases, have delivered insights into the physical and chemical parameters affecting anilinium salt stability. 1H NMR kinetic analysis of salt degradation has evidenced thermal degradation to methyl iodide and the parent aniline, consistent with a closed-shell SN2-centred degradative pathway, and methyl iodide being the key reactive species in applied methylation procedures. Furthermore, the effect of halide and non-nucleophilic counterions on salt degradation has been investigated, along with deuterium isotope and solvent effects. New mechanistic insights have enabled the investigation of the use of trimethylanilinium salts in O-methylation and in improved cross-coupling strategies. Finally, detailed computational studies have helped highlight limitations in the current state-of-the-art of solvation modelling of reaction in which the bulk medium undergoes experimentally observable changes over the reaction timecourse

Developing Secure Power Systems Professional Competence: Alignment and Gaps in Workforce Development Programs?Summary Report

This document is a summarization of the report, Developing Secure Power Systems Professional Competence: Alignment and Gaps in Workforce Development Programs, the final report for phase 2 of the SPSP (DOE workforce study) project

Species concepts in Cercospora: spotting the weeds among the roses

The genus Cercospora contains numerous important plant pathogenic fungi from a diverse range of hosts. Most species of Cercospora are known only from their morphological characters in vivo. Although the genus contains more than 5 000 names, very few cultures and associated DNA sequence data are available. In this study, 360 Cercospora isolates, obtained from 161 host species, 49 host families and 39 countries, were used to compile a molecular phylogeny. Partial sequences were derived from the internal transcribed spacer regions and intervening 5.8S nrRNA, actin, calmodulin, histone H3 and translation elongation factor 1-alpha genes. The resulting phylogenetic clades were evaluated for application of existing species names and five novel species are introduced. Eleven species are epi-, lecto- or neotypified in this study. Although existing species names were available for several clades, it was not always possible to apply North American or European names to African or Asian strains and vice versa. Some species were found to be limited to a specific host genus, whereas others were isolated from a wide host range. No single locus was found to be the ideal DNA barcode gene for the genus, and species identification needs to be based on a combination of gene loci and morphological characters. Additional primers were developed to supplement those previously published for amplification of the loci used in this study. TAXONOMIC NOVELTIES: New species - Cercospora coniogrammes Crous & R.G. Shivas, Cercospora delaireae C. Nakash., Crous, U. Braun & H.D. Shin, Cercospora euphorbiae-sieboldianae C. Nakash., Crous, U. Braun & H.D. Shin, Cercospora pileicola C. Nakash., Crous, U. Braun & H.D. Shin, Cercospora vignigena C. Nakash., Crous, U. Braun & H.D. Shin. Typifications: epitypifications - Cercospora alchemillicola U. Braun & C.F. Hill, Cercospora althaeina Sacc., Cercospora armoraciae Sacc., Cercospora corchori Sawada, Cercospora mercurialis Pass., Cercospora olivascens Sacc., Cercospora violae Sacc.; neotypifications - Cercospora fagopyri N. Nakata & S. Takim., Cercospora sojina Hara