155 research outputs found

    Soil Management Technologies and Mycotoxin Contamination of Wheat and Barley Grain

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    Fusarium head blight caused by a complex of Fusarium species is widespread across the world and ranks among the most serious diseases in cereals. Long-term field experiments were set up to evaluate the effects of preceding crop and soil management methods on Fusarium mycotoxin (DON, deoxynivalenol) contamination of winter wheat and spring barley grain. Winter wheat and spring barley were cultivated at two locations in the Czech Republic (A: Ivanovice na Hané during 2002–2014, and B: Žabčice during 2007–2014) with preceding crops (A) alfalfa, maize, and pea; and (B) alfalfa (only for wheat), sugar beet (only for barley), and maize. Different soil management methods also were used: (A) 22 cm tillage, 15 cm tillage, 10 cm chisel, and direct drilling; and (B) 22 cm tillage, 10 cm chisel, and direct drilling. Mycotoxin content in harvested grain was analysed using ELISA. At both locations in the experiments with both wheat and barley, year had a significant effect on mycotoxin content in grain. Preceding crop was another significant factor in wheat experiments at both locations, with DON content in grain higher with maize as the preceding crop than in the cases of other preceding crops. Soil management method had a significant effect only on mycotoxin content in wheat grain grown at Žabčice, and the highest DON content was determined in the chisel variant, in which case a large amount of harvest residue remained on the soil surface or was only partially incorporated

    Microstructure and mechanical properties of severely deformed AX41 magnesium alloy

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    The object of the present paper is the study of mechanical properties and microstructural evolution of AX41 magnesium alloy, severely deformed using a combination of hot extrusion and equal channel angular pressing. Equal channel angular pressing processing was performed at 250°C following route Bc. Mechanical properties of the ultrafine-grained alloy were investigated in tension at a constant strain rate of 10-4 s-1 at room temperature and 100 °C. The dislocation density was determined by X-ray line profiles analysis. Microstructural observations performed by electron backscattering diffraction after 8 passes of equal channel angular pressing revealed very fine and homogeneous microstructure with a grain size of 0.3-6 μm. It has been found that the room temperature mechanical properties such as yield stress and tensile strength reach their maximum value even after the first pass which is in good agreement with the evolution of the dislocation density. Further processing by equal channel angular pressing led to the decrease in both the yield strength and the dislocation density, despite the slight grain size refinement

    Expression of alternansucrase in potato plants

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    Alternan, which consists of alternating α-(1→3)/α-(1→6)-linked glucosyl residues, was produced in potato tubers by expressing a mature alternansucrase (Asr) gene from Leuconostoc mesenteroides NRRL B-1355 in potato. Detection of alternan was performed by enzyme-linked immunosorbent assay in tuber juices, revealing a concentration between 0.3 and 1.2 mg g-1 fresh wt. The Asr transcript levels correlated well with alternan accumulation in tuber juices. It appeared that the expression of sucrose-regulated starch-synthesizing genes (ADP-glucose pyrophosphorylase subunit S and granule-bound starch synthase I) was down-regulated. Despite this, the physico-chemical properties of the transgenic starches were unaltered. These results are compared to those obtained with other transgenic potato plants producing mutan [α-(1→3)-linked glucosyl residues] and dextran [α-(1→6)-linked glucosyl residues]

    Fatigue life of machined components

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    A correlation between machining process and fatigue strength of machined components clearly exists. However, a complete picture of the knowledge on this is not readily available for practical applications. This study addresses this issue by investigating the effects of machining methods on fatigue life of commonly used materials, such as titanium alloys, steel, aluminium alloys and nickel alloys from previous literature. Effects of turning, milling, grinding and different non-conventional machining processes on fatigue strength of above-mentioned materials have been investigated in detail with correlated information. It is found that the effect of materials is not significant except steel in which phase change causes volume expansion, resulting in compressive/tensile residual stresses based on the amounts of white layers. It is very complex to identify the influence of surface roughness on the fatigue strength of machined components in the presence of residual stresses. The polishing process improves the surface roughness, but removes the surface layers that contain compressive residual stresses to decrease the fatigue strength of polished specimens. The compressive and tensile residual stresses improve and reduce fatigue strength, respectively. Grinding process induces tensile residual stresses on the machined surfaces due to high temperature generation. On the other hand, milling and turning processes induce compressive residual stresses. High temperature non-conventional machining generates a network of micro-cracks on the surfaces in addition to tensile residual stresses to subsequently reduce fatigue strength of machined components. Embedded grits of abrasive water jet machining degrade the fatigue performance of components machined by this method

    A starting guide to root ecology: strengthening ecological concepts and standardising root classification, sampling, processing and trait measurements

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    In the context of a recent massive increase in research on plant root functions and their impact on the environment, root ecologists currently face many important challenges to keep on generating cutting-edge, meaningful and integrated knowledge. Consideration of the below-ground components in plant and ecosystem studies has been consistently called for in recent decades, but methodology is disparate and sometimes inappropriate. This handbook, based on the collective effort of a large team of experts, will improve trait comparisons across studies and integration of information across databases by providing standardised methods and controlled vocabularies. It is meant to be used not only as starting point by students and scientists who desire working on below-ground ecosystems, but also by experts for consolidating and broadening their views on multiple aspects of root ecology. Beyond the classical compilation of measurement protocols, we have synthesised recommendations from the literature to provide key background knowledge useful for: (1) defining below-ground plant entities and giving keys for their meaningful dissection, classification and naming beyond the classical fine-root vs coarse-root approach; (2) considering the specificity of root research to produce sound laboratory and field data; (3) describing typical, but overlooked steps for studying roots (e.g. root handling, cleaning and storage); and (4) gathering metadata necessary for the interpretation of results and their reuse. Most importantly, all root traits have been introduced with some degree of ecological context that will be a foundation for understanding their ecological meaning, their typical use and uncertainties, and some methodological and conceptual perspectives for future research. Considering all of this, we urge readers not to solely extract protocol recommendations for trait measurements from this work, but to take a moment to read and reflect on the extensive information contained in this broader guide to root ecology, including sections I–VII and the many introductions to each section and root trait description. Finally, it is critical to understand that a major aim of this guide is to help break down barriers between the many subdisciplines of root ecology and ecophysiology, broaden researchers’ views on the multiple aspects of root study and create favourable conditions for the inception of comprehensive experiments on the role of roots in plant and ecosystem functioning

    Nuclear localisation of Aurora-A: its regulation and significance for Aurora-A functions in cancer.

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    The Aurora-A kinase regulates cell division, by controlling centrosome biology and spindle assembly. Cancer cells often display elevated levels of the kinase, due to amplification of the gene locus, increased transcription or post-translational modifications. Several inhibitors of Aurora-A activity have been developed as anti-cancer agents and are under evaluation in clinical trials. Although the well-known mitotic roles of Aurora-A point at chromosomal instability, a hallmark of cancer, as a major link between Aurora-A overexpression and disease, recent evidence highlights the existence of non-mitotic functions of potential relevance. Here we focus on a nuclear-localised fraction of Aurora-A with oncogenic roles. Interestingly, this pool would identify not only non-mitotic, but also kinase-independent functions of the kinase. We review existing data in the literature and databases, examining potential links between Aurora-A stabilisation and localisation, and discuss them in the perspective of a more effective targeting of Aurora-A in cancer therapy

    Administracja, zarządzanie i handel zagraniczny w warunkach integracji. Materiały konferencyjne - Zarządzanie bezpieczeństwem

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    Ze wstępu: "Bezpieczeństwo jest w coraz wyższej cenie. Zajmują się nim naukowcy oraz praktycy z różnych dziedzin. W najszerszym wymiarze pojęcie „bezpieczeństwo” sprowadzić można do słów: stan niezagrożenia, spokoju, pewności. Takie ogólne ujęcie problematyki bezpieczeństwa sprawia, że różne podmioty podchodzą wybiórczo do tych bardzo ważnych zarówno dla pojedynczych ludzi, jak i społeczeństwa zagadnień. Inaczej postrzegają i interpretują bezpieczeństwo politycy, prawnicy, ekonomiści, wojskowi, policjanci, lekarze, pedagodzy, a inaczej zwyczajni ludzie. W ich ujęciu bezpieczeństwo to: 1) stan świadomości człowieka, w którym czuje się on wolny od jakichkolwiek zagrożeń, pociągający za sobą poczucie spokoju i komfortu; 2) niczym niezakłócone współistnienie człowieka z innymi ludźmi i środowiskiem przyrodniczym; 3) stan bez lęku i niepokoju o siebie i innych, pewność jutra; 4) brak zagrożenia utraty zdrowia, mienia i życia, komfort psychiczny umożliwiający realizację życiowych marzeń i celów; 5) sytuacja, w której człowiekowi nic nie zagraża, a w nagłych i nieprzewidzianych sytuacjach może liczyć na pomoc i wsparcie innych."(...
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