73 research outputs found

    Aβ Mediated Diminution of MTT Reduction—An Artefact of Single Cell Culture?

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    The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide (MTT) reduction assay is a frequently used and easily reproducible method to measure beta-amyloid (Aβ) toxicity in different types of single cell culture. To our knowledge, the influence of Aβ on MTT reduction has never been tested in more complex tissue. Initially, we reproduced the disturbed MTT reduction in neuron and astroglia primary cell cultures from rats as well as in the BV2 microglia cell line, utilizing four different Aβ species, namely freshly dissolved Aβ (25-35), fibrillar Aβ (1-40), oligomeric Aβ (1-42) and oligomeric Aβ (1-40). In contrast to the findings in single cell cultures, none of these Aβ species altered MTT reduction in rat organotypic hippocampal slice cultures (OHC). Moreover, application of Aβ to acutely isolated hippocampal slices from adult rats and in vivo intracerebroventricular injection of Aβ also did not influence the MTT reduction in the respective tissue. Failure of Aβ penetration into the tissue cannot explain the differences between single cells and the more complex brain tissue. Thus electrophysiological investigations disclosed an impairment of long-term potentiation (LTP) in the CA1 region of hippocampal slices from rat by application of oligomeric Aβ (1-40), but not by freshly dissolved Aβ (25-35) or fibrillar Aβ (1-40). In conclusion, the experiments revealed a glaring discrepancy between single cell cultures and complex brain tissue regarding the effect of different Aβ species on MTT reduction. Particularly, the differential effect of oligomeric versus other Aβ forms on LTP was not reflected in the MTT reduction assay. This may indicate that the Aβ oligomer effect on synaptic function reflected by LTP impairment precedes changes in formazane formation rate or that cells embedded in a more natural environment in the tissue are less susceptible to damage by Aβ, raising cautions against the consideration of single cell MTT reduction activity as a reliable assay in Alzheimer's drug discovery studies

    A Biobrick Library for Cloning Custom Eukaryotic Plasmids

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    Researchers often require customised variations of plasmids that are not commercially available. Here we demonstrate the applicability and versatility of standard synthetic biological parts (biobricks) to build custom plasmids. For this purpose we have built a collection of 52 parts that include multiple cloning sites (MCS) and common protein tags, protein reporters and selection markers, amongst others. Importantly, most of the parts are designed in a format to allow fusions that maintain the reading frame. We illustrate the collection by building several model contructs, including concatemers of protein binding-site motifs, and a variety of plasmids for eukaryotic stable cloning and chromosomal insertion. For example, in 3 biobrick iterations, we make a cerulean-reporter plasmid for cloning fluorescent protein fusions. Furthermore, we use the collection to implement a recombinase-mediated DNA insertion (RMDI), allowing chromosomal site-directed exchange of genes. By making one recipient stable cell line, many standardised cell lines can subsequently be generated, by fluorescent fusion-gene exchange. We propose that this biobrick collection may be distributed peer-to-peer as a stand-alone library, in addition to its distribution through the Registry of Standard Biological Parts (http://partsregistry.org/)

    Treatment of rising damp in historical buildings: wall base ventilation

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    Intervention in older buildings increasingly requires extensive and objective knowledge of what one will be working with. The multifaceted aspect of work carried out on buildings tends to encompass a growing number of specialities, with marked emphasis on learning the causes of many of the problems that affect these buildings and the possible treatments that can solve them. Moisture transfer in walls of old buildings, which are in direct contact with the ground, leads to a migration of soluble salts responsible for many building pathologies.http://www.sciencedirect.com/science/article/B6V23-4H7T0H7-1/1/f5e8a4ec173c5dadf120770678facf4

    Gendered Risk Perceptions Associated with Human-Wildlife Conflict: Implications for Participatory Conservation

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    This research aims to foster discourse about the extent to which gender is important to consider within the context of participatory approaches for biological conservation. Our objectives are to: (1) gender-disaggregate data about stakeholders' risk perceptions associated with human-wildlife conflict (HWC) in a participatory conservation context, and (2) highlight insights from characterizing gendered similarities and differences in the way people think about HWC-related risks. Two communal conservancies in Caprivi, Namibia served as case study sites. We analyzed data from focus groups (n = 2) to create gendered concept maps about risks to wildlife and livelihoods and any associations of those risks with HWC, and semi-structured interviews (n = 76; men = 38, women = 38) to measure explicit risk attitudes associated with HWC. Concept maps indicated some divergent perceptions in how groups characterized risks to wildlife and livelihoods; however, not only were identified risks to wildlife (e.g., pollution, hunting) dissimilar in some instances, descriptions of risks varied as well. Study groups reported similar risk perceptions associated with HWC with the exception of worry associated with HWC effects on local livelihoods. Gendered differences in risk perceptions may signal different priorities or incentives to participate in efforts to resolve HWC-related risks. Thus, although shared goals and interests may seem to be an obvious reason for cooperative wildlife management, it is not always obvious that management goals are shared. Opportunity exists to move beyond thinking about gender as an explanatory variable for understanding how different groups think about participating in conservation activities

    Paradigmatic or Critical? Resilience as a New Turn in EU Governance for the Neighbourhood

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    Rising from the margins of EU aid documents, resilience became a centrepiece of the 2016 EU Global Security Strategy, especially in relation to the neighbourhood. While new resilience-thinking may signify another paradigmatic shift in EU modus operandi, the question that emerges is whether it is critical enough to render EU governance a new turn, to make it sustainable? This article argues that in order for resilience-framed governance to become more effective, the EU needs not just engage with ‘the local’ by way of externally enabling their communal capacity. More crucially, the EU needs to understand resilience for what it is – a self-governing project – to allow ‘the local’ an opportunity to grow their own critical infrastructures and collective agency, in their pursuit of ‘good life’. Is the EU ready for this new thinking, and not just rhetorically or even methodologically when creating new instruments and subjectivities? The bigger question is whether the EU is prepared to critically turn the corner of its neoliberal agenda to accommodate emergent collective rationalities of self-governance as a key to make its peace-building project more successful

    Azerbaijan’s Foreign Policy Strategies and the European Union: Successful resistance and pursued influence

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    In recent years, Azerbaijan has positioned itself on the international scene as an increasingly important and assertive actor. This essay focuses on Azerbaijan’s relations with the European Union (EU). It will identify the policy strategies used by Azerbaijan to engage with the EU in two areas where their interests and objectives do not align, namely democracy and human rights promotion policies, and agenda-setting of the Nagorno-Karabakh conflict. The essay highlights, first, the relevance of national independence, ‘balancing’ and regime legitimacy in explaining Azerbaijan’s foreign policy strategies, and second, the mixed track record of Azerbaijan’s assertiveness, with different outcomes depending on whether the policy strategies are reactive or proactive

    TTBist: a DfT Tool for Enhancing Functional Test for SoC

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    ABSTRACT: The paper presents a new tool called TTBist for DfT synthesis of IP cores in Systems-on-a-Chip. While scan-based approaches have been known for a long time, they have shortcomings and they are rearly used in practice in smaller design companies. The current paper introduces a new alternative for this traditional method. The tool TTBist allows to automatically insert Built-In Self-Test (BIST) structures into sequential cores of the system. Alternatively, in cases when BIST proves inefficient, it synthesizes observers for functional test to the outputs of the cores. This considerably speeds up fault grading of the functional test for the system. TTBist is well integrated to common commercial design flows.
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