155 research outputs found

    Rock-eating mycorrhizas: their role in plant nutrition and biogeochemical cycles

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    A decade ago, tunnels inside mineral grains were found that were likely formed by hyphae of ectomycorrhizal (EcM) fungi. This observation implied that EcM fungi can dissolve mineral grains. The observation raised several questions on the ecology of these ¿rock-eating¿ fungi. This review addresses the roles of these rock-eating EcM associations in plant nutrition, biogeochemical cycles and pedogenesis. Research approaches ranged from molecular to ecosystem level scales. Nutrient deficiencies change EcM seedling exudation patterns of organic anions and thus their potential to mobilise base cations from minerals. This response was fungal species-specific. Some EcM fungi accelerated mineral weathering. While mineral weathering could also increase the concentrations of phytotoxic aluminium in the soil solution, some EcM fungi increase Al tolerance through an enhanced exudation of oxalate. Through their contribution to Al transport, EcM hyphae could be agents in pedogenesis, especially podzolisation. A modelling study indicated that mineral tunnelling is less important than surface weathering by EcM fungi. With both processes taken together, the contribution of EcM fungi to weathering may be significant. In the field vertical niche differentiation of EcM fungi was shown for EcM root tips and extraradical mycelium. In the field EcM fungi and tunnel densities were correlated. Our results support a role of rock-eating EcM fungi in plant nutrition and biogeochemical cycles. EcM fungal species-specific differences indicate the need for further research with regard to this variation in functional traits

    Toetsing van meststoffen en bemestingssystemen in de aardappelteelt; veldproeven 2006-2008

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    Er wordt in de praktijk veel informatie verspreid over de positieve aspecten van bepaalde (nieuwe) meststoffen en bemestingssystemen. In opdracht van Productschap Akkerbouw, een aantal meststoffenbedrijven, de Stichting Proefboerderij Prof. Dr. J.M. van Bemmelenhoeve en het Ministerie van LNV hebben NMI en PPO daarom de gebruikswaarde (o.a. effect op opbrengst en kwaliteit) van een aantal van die meststoffen en bemestingssystemen voor de teelt van poot-, zetmeel- en consumptieaardappelen vastgesteld. In aanvulling daarop is in de veldproeven met zetmeel- en consumptieaardappelen op zandgrond ook het effect op de efficiëntie van de toegediende stikstof onderzoch

    Naar een herziening van kali-advies grasland

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    Voor een optimale grasgroei moet K op het juiste moment in voldoende mate aanwezig zijn. Tegelijkertijd dient een te hoog aanbod van K te worden voorkomen om nadelige effecten voor de diergezondheid te vermijden. Het vigerende kalibemestingsadvies is gebaseerd op proeven uit de jaren vijftig en zestig met zware eerste sneden. Het advies is na 1976 vrijwel niet meer gewijzigd. Sindsdien is de landbouw sterk gewijzigd en zijn er nieuwe methoden voor grondonderzoek ontwikkeld

    Risicobeoordeling van contaminanten in afval- en reststoffen bestemd voor gebruik als covergistingsmateriaal

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    Een beoordeling is uitgevoerd van 21 stoffen die door LTO-Noord en de Biogas Branche Organisatie (BBO) aangemeld zijn voor opname in bijlage Aa van de Uitvoeringsregeling Meststoffenwet. Op verzoek van het ministerie EZ zijn daar 6 stoffen aan toegevoegd (21+6) en werden 119 eerder aangemelde stoffen herbeoordeeld. De beoordeling betreft met name de milieuhygienische consequenties van het gebruik van covergistingsmaterialen en het resulterende digestaat na vergisting. De beoordeling van de zware metaal- en arseengehalten en de door de Meststoffenwet aangewezen organische microverontreinigingen volgt het Protocol Beoordeling Stoffen eststoffenwet, versie 2.1. Expert judgement is toegepast in geval gegevens niet of niet volledig beschikbaar waren om dit protocol te kunnen toepassen. Criteria voor expert judgement zijn voor deze situatie opgesteld. Voor de beoordeling van de residuen van gewasbeschermingsmiddelen en biociden zijn drie alternatieve systematieken opgesteld, mede gebaseerd op toepassing van expert judgement. Het na te streven beschermingsniveau bepaalt welke systematiek gebruikt zal gaan worden. De 21+6 stoffen zijn beoordeeld volgens het protocol en opgestelde alternatieven. De toelating van covergistingsmaterialen in Vlaanderen, Denemarken en Duitsland is betrokken bij de beoordeling. Tenslotte worden aanbevelingen gedaan om te komen tot beleidsafwegingen en –keuzes inzake opgestelde alternatieven en tot een effectief protocol voor toelating van afval- en reststoffen als covergistingsmateriaal

    Deep learning from MRI-derived labels enables automatic brain tissue classification on human brain CT

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    Automatic methods for feature extraction, volumetry, and morphometric analysis in clinical neuroscience typically operate on images obtained with magnetic resonance (MR) imaging equipment. Although CT scans are less expensive to acquire and more widely available than MR scans, their application is currently limited to the visual assessment of brain integrity and the exclusion of co-pathologies. CT has rarely been used for tissue classification because the contrast between grey matter and white matter was considered insufficient. In this study, we propose an automatic method for segmenting grey matter (GM), white matter (WM), cerebrospinal fluid (CSF), and intracranial volume (ICV) from head CT images. A U-Net deep learning model was trained and validated on CT images with MRI-derived segmentation labels. We used data from 744 participants of the Gothenburg H70 Birth Cohort Studies for whom CT and T1-weighted MR images had been acquired on the same day. Our proposed model predicted brain tissue classes accurately from unseen CT images (Dice coefficients of 0.79, 0.82, 0.75, 0.93 and 0.98 for GM, WM, CSF, brain volume and ICV, respectively). To contextualize these results, we generated benchmarks based on established MR-based methods and intentional image degradation. Our findings demonstrate that CT-derived segmentations can be used to delineate and quantify brain tissues, opening new possibilities for the use of CT in clinical practice and research

    Map maker’s guide: a decision support system for interpolation, aggregation, and disaggregation : technical documentation

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    This report documents a decision support system (DSS) that has been developed to assist environmental researchers in selecting interpolation, aggregation, and disaggregation methods. The DSS has been implemented as a web-application. This facilitates updating and makes the DSS generally accessible. The DSS asks the user several questions. The answers are compared with those given by experts. The degree of similarity between both sets of answers is used to assign suitability scores to a huge set of interpolation, aggregation, and disaggregation methods stored in a database. These methods are ranked from most to least suitable and presented to the user in a dynamic table. The user can compare recommended methods (backgrounds, available software, literature, performance) and evaluate dynamically which methods would have been recommended if deferent answers had been given (what-if analysis

    Potential immunological consequences of pharmacological suppression of gastric acid production in patients with multiple sclerosis

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    Corticosteroids are standard treatment for patients with multiple sclerosis experiencing acute relapse. Because dyspeptic pain is a common side effect of this intervention, patients can be given a histamine receptor-2 antagonist, proton pump inhibitor or antacid to prevent or ameliorate this disturbance. Additionally, patients with multiple sclerosis may be taking these medications independent of corticosteroid treatment. Interventions for gastric disturbances can influence the activation state of the immune system, a principal mediator of pathology in multiple sclerosis. Although histamine release promotes inflammation, activation of the histamine receptor-2 can suppress a proinflammatory immune response, and blocking histamine receptor-2 with an antagonist could shift the balance more towards immune stimulation. Studies utilizing an animal model of multiple sclerosis indicate that histamine receptor-2 antagonists potentially augment disease activity in patients with multiple sclerosis. In contrast, proton pump inhibitors appear to favor immune suppression, but have not been studied in models of multiple sclerosis. Antacids, histamine receptor-2 antagonists and proton pump inhibitors also could alter the intestinal microflora, which may indirectly lead to immune stimulation. Additionally, elevated gastric pH can promote the vitamin B12 deficiency that patients with multiple sclerosis are at risk of developing. Here, we review possible roles of gastric acid inhibitors on immunopathogenic mechanisms associated with multiple sclerosis

    Heat-Induced Structural Changes Affect OVA-Antigen Processing and Reduce Allergic Response in Mouse Model of Food Allergy

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    BACKGROUND AND AIMS: The egg protein ovalbumin (OVA) belongs to six most frequent food allergens. We investigated how thermal processing influences its ability to induce allergic symptoms and immune responses in mouse model of food allergy. METHODOLOGY/PRINCIPAL FINDINGS: Effect of increased temperature (70°C and 95°C) on OVA secondary structure was characterized by circular dichroism and by the kinetics of pepsin digestion with subsequent HPLC. BALB/c mice were sensitized intraperitoneally and challenged with repeated gavages of OVA or OVA heated to 70°C (h-OVA). Levels of allergen-specific serum antibodies were determined by ELISA (IgA and IgGs) or by β-hexosaminidase release test (IgE). Specific activities of digestive enzymes were determined in brush border membrane vesicles of jejunal enterocytes. Cytokine production and changes in regulatory T cells in mesenteric lymph nodes and spleen were assessed by ELISA and FACS. Heating of OVA to 70°C caused mild irreversible changes in secondary structure compared to boiling to 95°C (b-OVA), but both OVA treatments led to markedly different digestion kinetics and Tregs induction ability in vitro, compared to native OVA. Heating of OVA significantly decreased clinical symptoms (allergic diarrhea) and immune allergic response on the level of IgE, IL-4, IL-5, IL-13. Furthermore, h-OVA induced lower activities of serum mast cell protease-1 and enterocyte brush border membrane alkaline phosphatase as compared to native OVA. On the other hand h-OVA stimulated higher IgG2a in sera and IFN-γ secretion by splenocytes. CONCLUSIONS: Minor irreversible changes in OVA secondary structure caused by thermal processing changes both its digestion and antigenic epitopes formation, which leads to activation of different T cell subpopulations, induces shift towards Th1 response and ultimately reduces its allergenicity

    ARIA 2016:Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

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    The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma and rhinitis and (3) to develop guidelines with all stakeholders that could be used globally for all countries and populations. ARIA-disseminated and implemented in over 70 countries globally-is now focusing on the implementation of emerging technologies for individualized and predictive medicine. MASK [MACVIA (Contre les Maladies Chroniques pour un Vieillissement Actif)-ARIA Sentinel NetworK] uses mobile technology to develop care pathways for the management of rhinitis and asthma by a multi-disciplinary group and by patients themselves. An app (Android and iOS) is available in 20 countries and 15 languages. It uses a visual analogue scale to assess symptom control and work productivity as well as a clinical decision support system. It is associated with an inter-operable tablet for physicians and other health care professionals. The scaling up strategy uses the recommendations of the European Innovation Partnership on Active and Healthy Ageing. The aim of the novel ARIA approach is to provide an active and healthy life to rhinitis sufferers, whatever their age, sex or socio-economic status, in order to reduce health and social inequalities incurred by the disease

    ARIA 2016 : Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

    Get PDF
    The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma and rhinitis and (3) to develop guidelines with all stakeholders that could be used globally for all countries and populations. ARIA-disseminated and implemented in over 70 countries globally-is now focusing on the implementation of emerging technologies for individualized and predictive medicine. MASK [MACVIA (Contre les Maladies Chroniques pour un Vieillissement Actif)-ARIA Sentinel NetworK] uses mobile technology to develop care pathways for the management of rhinitis and asthma by a multi-disciplinary group and by patients themselves. An app (Android and iOS) is available in 20 countries and 15 languages. It uses a visual analogue scale to assess symptom control and work productivity as well as a clinical decision support system. It is associated with an inter-operable tablet for physicians and other health care professionals. The scaling up strategy uses the recommendations of the European Innovation Partnership on Active and Healthy Ageing. The aim of the novel ARIA approach is to provide an active and healthy life to rhinitis sufferers, whatever their age, sex or socio-economic status, in order to reduce health and social inequalities incurred by the disease.Peer reviewe
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