452 research outputs found

    Magnetic field in an apartment located above 10/0.4 kV substation: Levels and mitigation techniques

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    The paper presents a real case of non-ionising radiation testing in an apartment located directly above a 10/0.4 kV substation in Serbia. In order to check the compliance with national regulations on protection of population from non-ionising radiation, it was necessary to perform measurements of magnetic flux density in the apartment. After the first measurements were performed, the distribution company implemented a mitigation technique by placing a passive conductive shield inside the substation in order to decrease magnetic field levels in the apartment. Measurements performed after the mitigation technique had been implemented have shown that the applied shield had an impact on magnetic field reduction to a certain extent. However, since the obtained shielding factor was not very high, the authors analysed another possible shielding solution which would provide higher shielding factor and consequently lower magnetic field levels in the apartment. Both shielding solutions and the results they provide are presented and analysed

    Protocols for the delivery of small molecules to the two-spotted spider mite, Tetranychus urticae

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    The two-spotted spider mite, Tetranychus urticae, is a chelicerate herbivore with an extremely wide host range and an extraordinary ability to develop pesticide resistance. Due to its responsiveness to natural and synthetic xenobiotics, the spider mite is becoming a prime pest herbivore model for studies of the evolution of host range, plant-herbivore interactions and mechanisms of xenobiotic resistance. The spider mite genome has been sequenced and its transcriptional responses to developmental and various biotic and abiotic cues have been documented. However, to identify biological and evolutionary roles of T. urticae genes and proteins, it is necessary to develop methods for the efficient manipulation of mite gene function or protein activity. Here, we describe protocols developed for the delivery of small molecules into spider mites. Starting with mite maintenance and the preparation of the experimental mite populations of developmentally synchronized larvae and adults, we describe 3 methods for delivery of small molecules including artificial diet, leaf coating, and soaking. The presented results define critical steps in these methods and demonstrate that they can successfully deliver tracer dyes into mites. Described protocols provide guidelines for high-throughput setups for delivery of experimental compounds that could be used in reverse genetics platforms to modulate gene expression or protein activity, or for screens focused on discovery of new molecules for mite control. In addition, described protocols could be adapted for other Tetranychidae and related species of economic importance such as Varroa, dust and poultry mites. © 2017 Suzuki et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    Structural and functional characterization of an intradiol ring-cleavage dioxygenase from the polyphagous spider mite herbivore Tetranychus urticae Koch

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    Genome analyses of the polyphagous spider mite herbivore Tetranychus urticae (two-spotted spider mite) revealed the presence of a set of 17 genes that code for secreted proteins belonging to the "intradiol dioxygenase-like" subgroup. Phylogenetic analyses indicate that this novel enzyme family has been acquired by horizontal gene transfer. In order to better understand the role of these proteins in T. urticae, we have structurally and functionally characterized one paralog (tetur07g02040). It was demonstrated that this protein is indeed an intradiol ring-cleavage dioxygenase, as the enzyme is able to cleave catechol between two hydroxyl-groups using atmospheric dioxygen. The enzyme was characterized functionally and structurally. The active site of the T. urticae enzyme contains an Fe3+ cofactor that is coordinated by two histidine and two tyrosine residues, an arrangement that is similar to those observed in bacterial homologs. However, the active site is significantly more solvent exposed than in bacterial proteins. Moreover, the mite enzyme is monomeric, while almost all structurally characterized bacterial homologs form oligomeric assemblies. Tetur07g02040 is not only the first spider mite dioxygenase that has been characterized at the molecular level, but is also the first structurally characterized intradiol ring-cleavage dioxygenase originating from a eukaryote

    Life history parameters in acellular extrinsic fiber cementum microstructure

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    Life-history parameters such as pregnancies, skeletal trauma, and renal disease have previously been identified from hypomineralized growth layers (incremental lines) of acellular extrinsic fiber cementum (AEFC). The precise periodicity of these growth layers remains vaguely approximated, so causal life-history explanations using tooth cementum cannot yet be rigorously calculated or tested. On the other hand, we show how life history parameters in AEFC can be identified by two contrasting elemental detection methods. Based on our results we reject the possibility of accurate estimation of pregnancies and other life history parameters from cementum using scanning electron microscopy alone. Here, we propose a new methodological approach for cementum research, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), to measure degree and distribution of mineralization of cementum growth layers. Our results show that Tof-SIMS can significantly increase our knowledge of cementum composition and is therefore a powerful new tool for life history researchers

    Conversion of supraventricular arrhythmias to sinus rhythm using flecainide

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    We evaluated the efficacy of flecainide acetate (given intravenously to a maximal dose of2 mg kg−1 and then orally in a dose of 100 mg b.d. or 100 mg t.d.s.) in the conversion to sinus rhythm of 50 patients exhibiting supraventricular arrhythmias (39 with atrial fibrillation, 6 with atrial flutter, 4 with supraventricu tachycardia and onewith supraventricular tachycardia in association with the Wolff—Parkinson—White syndrome). Conversion was achieved in 36 patients (72%) (29 cases with atrial fibrillation, 4 cases with supraventricular tachycardia, 2 cases with atrial flutter and one case with Wolff—Parkinson-White syndrome), over a mean period of 7.4 ± 9 h. The patients in which conversion was achieved had arrhythmias which had been in existence for a shorter time (5.3 ± 9.8 days) than those in which conversion was not achieved (16.7 ± 26.2 days) (P<0.01). The mean dosage of flecainide used to achieve conversion was 2.5 ± 2.36 mg kg−1. Flecainide appears to be an effective agent for the conversion to sinus rhythm of atrial fibrillation and supraventricular tachycardias. Its efficacy in cases of atrial flutter has not yet been demonstrate

    Material Modelling of Short Fiber Reinforced Thermoplastic for the FEA of a Clinching Test

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    In modern car body construction, multi-material and hybrid design is used, whereby short fibre reinforced plastics combined with light metals represent an interesting class of work-piece materials. In order to realize modern hybrid construction, suitable joining techniques are therefore required. Clinching represents a cost-effective and easy to implement joining method. In this paper the material modelling of the short fibre reinforced thermoplastic sheets considering the fibre orientation tensor for the FEA of the clinching process is presented

    Control of Penicillium Verrucosum var. cyclopium in cream cheese by Agaricus bohusii extract

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    Food processors, food safety researchers, and regulatory agencies have bean increasingly concerned with the growing number of food-borne illness outbreaks caused by different fungal pathogens. Mushrooms could be a potentially useful sources of antimicrobial compounds. Agaricus bohusii is edible, taste and prized mushroom from Agraicaceae family. We tested ethanol extract of this mushroom as a natural food preservative. Extract was added in cream cheese infected with food contaminating microfungi P. verucosum var. eye/opium (previously isolated from cheese) in different concentration (10-100 mg/ml). Solutions were kept at room temperature and -at +4°C and dally observed during 7 days. Growth inhibition of P. verucosum var. eye/opium by ethanol extract of A. bohusli is calculated as a percent of inhibition. There Is no growth of microfungi at second day after the incubation at the samples kept at +4°C, samples at 25°C showed different growth Inhibition depending on extract concentration. Growth inhibition percentage of extract toward microfungal at 4th day can be presented as following: 13.3-53.3 % at +4"C and 100 % on all concentration at room temperature. The growth inhibition of microfungi was also observed at 7th day but on higher level. 83.3-90.0% In refrigerator, while dose depending factor was not observed at the samples kept at room temperature. On all concentration tested the growth Inhibition was 100 %. It looks that the lowest concentration (10 mg) of mushroom extract was either strongly effective as the highest one (100 mg) at room temperature. Because of increasing pressure of consumers and legal authorities, the food industry has tended to reduce the use of chemical preservatives in their products to either completely nil or to adopt more natural alternatives for the maintenance or extension of product shelf life. In this manner mushroom extracts may replace conventional chemical antimicrobials
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