42 research outputs found

    Refined clothespin relocation test and assessment of motion

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    Background: Advancements in upper limb prosthesis design have focused on providing increased degrees of freedom for the end effector through multiple articulations of a prosthetic hand, wrist and elbow. Measuring improvement in patient function with these devices requires development of appropriate assessment tools. Objectives: This study presents a refined clothespin relocation test for measuring performance and assessing compensatory motion between able-bodied subjects and subjects with upper limb impairments. Study Design: Comparative analysis Methods: Trunk and head motions of 13 able-bodied subjects who performed the refined clothespin relocation test were compared to the motion of a transradial prosthesis user with a single degree of freedom hand. Results: There were observable differences between the prosthesis user and the able-bodied group. The assessment used provided a clear indication of the differences in motion through analysis of compensatory motion. Conclusion: The refined clothespin relocation test provides additional benefits over the standard clothespin assessment and makes identification of compensatory motions easily identifiable to the researcher. While this paper establishes the method for the new assessment, further validation will need to be performed with more users

    Media(ted) discourses and climate change : a focus on political subjectivity and (dis)engagement

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    Research has shown that the media are the main source of information and the main factor shaping people’s awareness and concern in relation to climate change and therefore have an important role in setting the public agenda. As a key forum for the production, reproduction and transformation of the meaning of public issues, the media influence understandings of risks, responsibilities, as well as of the functioning of democratic politics. This article argues that the media also matter to citizens’ perception of their (potential) political agency or their political subjectivity. Media representations construct particular β€˜subject positions’ for individuals and cultivate dispositions to action or inaction. The article discusses the importance of citizens’ political engagement with climate change and points out some aspects of media(ted) discourses that may constrain the perceived possibilities of participation in the politics of climate change. While engagement with climate change has multiple dimensions and a number of barriers have been identified through empirical studies, this article offers a critique of the role of the media in political engagement with the problem and suggests avenues for future research.The author is grateful to the Portuguese Funda A, o para a CiIncia e a Tecnologia for funding the project 'The Politics of Climate Change: Discourses and Representations' (POCI/COM56973/2004), to Jan Zienkowski for relevant comments on this paper, and to the reviewers who provided detailed feedback

    Functional characterization of the trans-membrane domain interactions of the Sec61 protein translocation complex beta-subunit

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    <p>Abstract</p> <p>Background</p> <p>In eukaryotic cells co- and post-translational protein translocation is mediated by the trimeric Sec61 complex. Currently, the role of the Sec61 complex Ξ²-subunit in protein translocation is poorly understood. We have shown previously that in <it>Saccharomyces cerevisiae </it>the trans-membrane domain alone is sufficient for the function of the Ξ²-subunit Sbh1p in co-translational protein translocation. In addition, Sbh1p co-purifies not only with the protein translocation channel subunits Sec61p and Sss1p, but also with the reticulon family protein Rtn1p.</p> <p>Results</p> <p>We used random mutagenesis to generate novel Sbh1p mutants in order to functionally map the Sbh1p trans-membrane domain. These mutants were analyzed for their interactions with Sec61p and how they support co-translational protein translocation. The distribution of mutations identifies one side of the Sbh1p trans-membrane domain Ξ±-helix that is involved in interactions with Sec61p and that is important for Sbh1p function in protein translocation. At the same time, these mutations do not affect Sbh1p interaction with Rtn1p. Furthermore we show that Sbh1p is found in protein complexes containing not only Rtn1p, but also the two other reticulon-like proteins Rtn2p and Yop1p.</p> <p>Conclusion</p> <p>Our results identify functionally important amino acids in the Sbh1p trans-membrane domain. In addition, our results provide additional support for the involvement of Sec61Ξ² in processes unlinked to protein translocation.</p

    A Membrane Fusion Protein Ξ±SNAP Is a Novel Regulator of Epithelial Apical Junctions

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    Tight junctions (TJs) and adherens junctions (AJs) are key determinants of the structure and permeability of epithelial barriers. Although exocytic delivery to the cell surface is crucial for junctional assembly, little is known about the mechanisms controlling TJ and AJ exocytosis. This study was aimed at investigating whether a key mediator of exocytosis, soluble N-ethylmaleimide sensitive factor (NSF) attachment protein alpha (Ξ±SNAP), regulates epithelial junctions. Ξ±SNAP was enriched at apical junctions in SK-CO15 and T84 colonic epithelial cells and in normal human intestinal mucosa. siRNA-mediated knockdown of Ξ±SNAP inhibited AJ/TJ assembly and establishment of the paracellular barrier in SK-CO15 cells, which was accompanied by a significant down-regulation of p120-catenin and E-cadherin expression. A selective depletion of p120 catenin effectively disrupted AJ and TJ structure and compromised the epithelial barrier. However, overexpression of p120 catenin did not rescue the defects of junctional structure and permeability caused by Ξ±SNAP knockdown thereby suggesting the involvement of additional mechanisms. Such mechanisms did not depend on NSF functions or induction of cell death, but were associated with disruption of the Golgi complex and down-regulation of a Golgi-associated guanidine nucleotide exchange factor, GBF1. These findings suggest novel roles for Ξ±SNAP in promoting the formation of epithelial AJs and TJs by controlling Golgi-dependent expression and trafficking of junctional proteins

    Toward Global Civil Society?

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    Non-governmental organizations are no longer a peripheral actor on the world stage. NGOs in both the South and the North have grown dramatically in recent years. The UNDP suggests that there were probably close to 50 000 NGOs in developing countries in the 1980s, many of which could not survive without assistance from the North.1 However, NGOs’ real impact and significance is only poorly understood. NGO staff have little time to think about the broader political and social implications of their activities since they are often overworked and absorbed in day-to-day problems. As well, much of the existing literature on development is not very helpful for evaluating the significance of NGOs or guiding their action
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