Development and validation of an analytical methodology based on solvent extraction and gas chromatography for determining pesticides in royal jelly and propolis

Producción CientíficaWe propose a new analytical methodology to determine seven pesticides (atrazine, chlorpyrifos, chlorfenvinphos, α-endosulfan, bromopropylate, coumaphos, and τ-fluvalinate) in royal jelly and propolis products using gas chromatography-mass spectrometry. Sample treatment, with minor modifications for propolis, consisted of a solvent extraction with a hexane and isopropanol mixture, and a further clean-up step. Meanwhile, chromatographic analysis (<25 min) was performed in a DB-5MS column under programmed temperature conditions. In all cases we validated the method in terms of selectivity, limits of detection (0.1–2.8 μg kg−1) and quantification (0.3–9.2 μg kg−1), linearity, matrix effect (<±20 %), trueness (recoveries between 93 % and 118 %), and precision (relative standard deviation < 11 %). All royal jelly liquid dietary supplements were positive for chlorfenvinphos and, in the case of one of them, for α-endosulfan; chlorfenvinphos was determined in some fresh royal jelly samples, and no pesticide residues were detected in the propolis samples analysedPlan Nacional de Investigación e Innovación Científica y Técnica, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria-INIA-FEDER (grant number RTA2017-00004-C02-02

Space-vector PWM with common-mode voltage elimination for multiphase drives

Switching common-mode voltage (CMV) generated by the pulse width modulation (PWM) of the inverter causes common-mode currents, which lead to motor bearing failures and electromagnetic interference problems in multiphase drives. Such switching CMV can be reduced by taking advantage of the switching states of multilevel multiphase inverters that produce zero CMV. Specific space-vector PWM (SVPWM) techniques with CMV elimination, which only use zero CMV states, have been proposed for three-level five-phase drives, and for open-end winding five-, six-, and seven-phase drives, but such methods cannot be extended to a higher number of levels or phases. This paper presents a general (for any number of levels and phases) SVPMW with CMV elimination. The proposed technique can be applied to most multilevel topologies, has low computational complexity and is suitable for low-cost hardware implementations. The new algorithm is implemented in a low-cost field-programmable gate array and it is successfully tested in the laboratory using a five-level five-phase motor drive.Ministerio de Ciencia e InnovaciónEuropean CommissionMinisterio de Economía y Competitividad | Ref. DPI2012-31283Ministerio de Economía y Competitividad | Ref. DPI2015-6541

New lichen biota records from Santuario Histórico de Machu Picchu, Peru

Los líquenes (hongos liquenizados) son organismos que presentan una alta diversidad, especialmente en las regiones tropicales; sin embargo, en Perú su conocimiento aún es escaso. Utilizando una metodología convencional, así como literatura actualizada sobre la descripción de géneros y especies, se presenta una lista de los macro-líquenes presentes en el Santuario Histórico de Machu Picchu (Cusco, Perú). Se reportan 67 especies de macro-líquenes, 9 de los cuales son nuevos registros para el Perú. Las familias Parmeliaceae, Physiciaceae y Lobariaceae son las que presentan mayor riqueza de especies en el área de estudio.While high species diversity of lichen - lichenized fungi - is reported especially in the tropics, the studies on these organisms are still scarce in Peru. Using conventional methodology and current literature on the description of genera and species, we reported macro-lichens collected from Historic Sanctuary of Machu Picchu (Cusco, Peru). Sixty seven species of macro-lichens are reported to SHMP, nine new records to Peru are documented. Parmeliaceae, Physciaceae and Lobariaceae are the families with major number of species

Biogeography and Genetic Structure in Populations of a Widespread Lichen (<i>Parmelina tiliacea</i>, <i>Parmeliaceae</i>, <i>Ascomycota</i>)

<div><p>The genetic diversity and population structure of the foliose lichenized fungus <i>Parmelina tiliacea</i> has been analyzed through its geographical range, including samples from Macaronesia (Canary Islands), the Mediterranean, and Eurosiberia. DNA sequences from the nuclear ribosomal internal transcribed spacer, the mitochondrial large subunit ribosomal RNA gene, and the translation elongation factor 1-α were used as molecular markers. The haplotypes of the three markers and the molecular variance analyses of multilocus haplotypes showed the highest diversity in the Canary Islands, while restricted haplotypes occurred at high frequencies in Mediterranean coastal samples. The multilocus haplotypes formed three unevenly distributed clusters (clusters 1-3). In the Canary Islands all the haplotypes were present in a similar proportion, while the coastal Mediterranean sites had almost exclusively haplotypes of cluster 3; cluster 2 predominated in inland Mediterranean sites; and cluster 1 was more abundant in central and northern Europe (Eurosiberian area). The distribution of clusters is partially explained by climatic factors, and its interaction with local spatial structure, but much of the variation remains unexplained. The high frequency of individuals in the Canary Islands with haplotypes shared with other areas suggests that could be a refugium of genetic diversity, and the high frequency of individuals of the Mediterranean coastal sites with restricted haplotypes indicates that gene flow to contiguous areas may be restricted. This is significant for the selection of areas for conservation purposes, as those with most genetic variation may reflect historical factors and biological properties of the species.</p></div

Inferred ancestry of individuals of <i>Parmelina tiliacea</i> from each site grouped by geographical areas.

<p>Collection sites numbered as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126981#pone.0126981.s001" target="_blank">S1 Table</a>. Each individual is represented by a single vertical line, broken into colored segments with lengths proportional to each of the three inferred clusters. Admixed individuals marked with an asterisk.</p

Median joining networks of three fungal markers.

<p>Pie charts numbered with haplotype codes as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126981#pone.0126981.s002" target="_blank">S2 Table</a>, proportional in size to the number of samples containing this haplotype, and colored according to the geographical area. Small numbers on lines indicate branch lengths.</p