86 research outputs found

    Self-assembling dipeptide antibacterial nanostructures with membrane disrupting activity.

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    Peptide-based supramolecular assemblies are a promising class of nanomaterials with important biomedical applications, specifically in drug delivery and tissue regeneration. However, the intrinsic antibacterial capabilities of these assemblies have been largely overlooked. The recent identification of common characteristics shared by antibacterial and self-assembling peptides provides a paradigm shift towards development of antibacterial agents. Here we present the antibacterial activity of self-assembled diphenylalanine, which emerges as the minimal model for antibacterial supramolecular polymers. The diphenylalanine nano-assemblies completely inhibit bacterial growth, trigger upregulation of stress-response regulons, induce substantial disruption to bacterial morphology, and cause membrane permeation and depolarization. We demonstrate the specificity of these membrane interactions and the development of antibacterial materials by integration of the peptide assemblies into tissue scaffolds. This study provides important insights into the significance of the interplay between self-assembly and antimicrobial activity and establishes innovative design principles toward the development of antimicrobial agents and materials

    Associations of hemoglobin A1c with cognition reduced for long diabetes duration

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    IntroductionAssociations of some risk factors with poor cognition, identified prior to age 75, are reduced or reversed in very old age. The Protected Survivor Model predicts this interaction due to enhanced survival of those with extended risk factor duration. In a younger sample, this study examines the association of cognition with the mean hemoglobin A1c risk factor over the time at risk, according to its duration.MethodsThe interaction of mean hemoglobin A1c (averageĆ¢ =Ć¢ 9.8%), evaluated over duration (averageĆ¢ =Ć¢ 116.8Ć¢ months), was examined for overall cognition and three cognitive domains in a sample of 150 Ć¢ youngĆ¢ oldĆ¢ veterans (mean ageĆ¢ =Ć¢ 70) with type 2 diabetes.ResultsThe predicted interactions were significant for overall cognition and attention, but not executive functions/language and memory.DiscussionFindings extend the Protected Survivor Model to a Ć¢ youngĆ¢ oldĆ¢ sample, from the very old. This model suggests focusing on individuals with good cognition despite prolonged high risk when seeking protective factors.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152553/1/trc2jtrci201911009.pd

    Studying the Functional Genomics of Stress Responses in Loblolly Pine With the Expresso Microarray Experiment Management System

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    Conception, design, and implementation of cDNA microarray experiments present a variety of bioinformatics challenges for biologists and computational scientists. The multiple stages of data acquisition and analysis have motivated the design of Expresso, a system for microarray experiment management. Salient aspects of Expresso include support for clone replication and randomized placement; automatic gridding, extraction of expression data from each spot, and quality monitoring; flexible methods of combining data from individual spots into information about clones and functional categories; and the use of inductive logic programming for higher-level data analysis and mining. The development of Expresso is occurring in parallel with several generations of microarray experiments aimed at elucidating genomic responses to drought stress in loblolly pine seedlings. The current experimental design incorporates 384 pine cDNAs replicated and randomly placed in two specific microarray layouts. We describe the design of Expresso as well as results of analysis with Expresso that suggest the importance of molecular chaperones and membrane transport proteins in mechanisms conferring successful adaptation to long-term drought stress

    Roadmap for a sustainable circular economy in lithium-ion and future battery technologies

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    The market dynamics, and their impact on a future circular economy for lithium-ion batteries (LIB), are presented in this roadmap, with safety as an integral consideration throughout the life cycle. At the point of end-of-life (EOL), there is a range of potential optionsā€”remanufacturing, reuse and recycling. Diagnostics play a significant role in evaluating the state-of-health and condition of batteries, and improvements to diagnostic techniques are evaluated. At present, manual disassembly dominates EOL disposal, however, given the volumes of future batteries that are to be anticipated, automated approaches to the dismantling of EOL battery packs will be key. The first stage in recycling after the removal of the cells is the initial cell-breaking or opening step. Approaches to this are reviewed, contrasting shredding and cell disassembly as two alternative approaches. Design for recycling is one approach that could assist in easier disassembly of cells, and new approaches to cell design that could enable the circular economy of LIBs are reviewed. After disassembly, subsequent separation of the black mass is performed before further concentration of components. There are a plethora of alternative approaches for recovering materials; this roadmap sets out the future directions for a range of approaches including pyrometallurgy, hydrometallurgy, short-loop, direct, and the biological recovery of LIB materials. Furthermore, anode, lithium, electrolyte, binder and plastics recovery are considered in order to maximise the proportion of materials recovered, minimise waste and point the way towards zero-waste recycling. The life-cycle implications of a circular economy are discussed considering the overall system of LIB recycling, and also directly investigating the different recycling methods. The legal and regulatory perspectives are also considered. Finally, with a view to the future, approaches for next-generation battery chemistries and recycling are evaluated, identifying gaps for research. This review takes the form of a series of short reviews, with each section written independently by a diverse international authorship of experts on the topic. Collectively, these reviews form a comprehensive picture of the current state of the art in LIB recycling, and how these technologies are expected to develop in the future

    Networked Learning in 2021: A Community Definition

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    Introduction (Networked Learning Editorial Collective): Since the turn of this century, much of the world has undergone a tectonic socio-technological change. Computers have left the isolated basements of research institutes and entered people's homes. Network connectivity has advanced from slow and unreliable modems to high-speed broadband. Devices have evolved: from stationary desktop computers to ever-present, always-connected smartphones. These developments have been accompanied by new digital practices, and changing expectations, not least in education, where enthusiasm for digital technologies has been kindled by quite contrasting sets of values. For example, some critical pedagogues working in the traditions of Freire and Illich have understood computers as novel tools for political and social emancipation, while opportunistic managers in cash-strapped universities have seen new opportunities for saving money and/or growing revenues. Irrespective of their ideological leanings, many of the early attempts at marrying technology and education had some features in common: instrumentalist understanding of human relationships with technologies, with a strong emphasis on practice and 'what works'. It is now clear that, in many countries, managerialist approaches have provided the framing, while local constraints and exigencies have shaped operational details, in fields such as e-learning, Technology Enhanced Learning, and others waving the 'Digital' banner. Too many emancipatory educational movements have ignored technology, burying their heads in the sand, or have wished it away, subscribing toa new form of Luddism, even as they sense themselves moving to the margins. But this situation is not set in stone. Our postdigital reality results from a complex interplay between centres and margins. Furthermore, the concepts of centres and margins 'have morphed into formations that we do not yet understand, and they have created (power) relationships which are still unsettled. The concepts ā€¦ have not disappeared, but they have become somewhat marginal in their own right.' (Jandrić andHayes 2019) Social justice and emancipation are as important as ever, yet they require new theoretical reconfigurations and practices fit for our socio-technological moment. In the 1990s, networked learning (NL) emerged as a critical response to dominant discourses of the day. NL went against the grain in two main ways. First, it embarked on developing nuanced understandings of relationships between humans and technologies; understandings which reach beyond instrumentalism and various forms of determinism. Second, NL embraced the emancipatory agenda of the critical pedagogy movement and has, in various ways, politically committed to social justice (Beaty et al. 2002; Networked Learning Editorial Collective 2020). Gathered around the biennial Networked Learning Conference,1 the Research in NetworkedLearning book series,2 and a series of related projects and activities, the NL community has left a significant trace in educational transformations over the last few decades. Twenty years ago, founding members of the NL community offered a definition of NL which has strongly influenced the NL communityā€™s theoretical perspectives and research approaches (Goodyear et al. 2004).3 Since then, however, the world has radically changed. With this in mind, the Networked Learning Editorial Collective (NLEC) recently published a paper entitled 'Networked Learning: InvitingRedefinition' (2020). In line with NL's critical agenda, a core goal for the paper was to open up a broad discussion about the current meaning and understandings of NL and directions for its further development. The current collectively authored paper presents the responses to the NLEC's open call. With 40 contributors coming from six continents and working across many fields of education, the paper reflects the breadth and depth of current understandings of NL. The responses have been collated, classified into main themes, and lightly edited for clarity. One of the responders, Sarah Hayes, was asked to write aconclusion. The final draft paper has undergone double open review. The reviewers, Laura Czerniewicz and Jeremy Knox, are acknowledged as authors. Our intention, in taking this approach, has been to further stimulate democratic discussion about NL and to prompt some much-needed community-building.lic

    Data from: Computational and experimental characterization of dVHL establish a Drosophila model of VHL syndrome

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    The von Hippel-Lindau (VHL) cancer syndrome is associated with mutations in the VHL gene. The pVHL protein is involved in response to changes in oxygen availability as part of an E3-ligase that targets the Hypoxia-Inducible Factor for degradation. pVHL has a molten globule configuration with marginal thermodynamic stability. The cancer-associated mutations further destabilize it. The Drosophila homolog, dVHL, has relatively low sequence similarity to pVHL, and is also involved in regulating HIF1-Ī±. Using in silico, in vitro and in vivo approaches we demonstrate high similarity between the structure and function of dVHL and pVHL. These proteins have a similar fold, secondary and tertiary structures, as well as thermodynamic stability. Key functional residues in dVHL are evolutionary conserved. This structural homology underlies functional similarity of both proteins, evident by their ability to bind their reciprocal partner proteins, and by the observation that transgenic pVHL can fully maintain normal dVHL-HIF1-Ī± downstream pathways in flies. This novel transgenic Drosophila model is thus useful for studying the VHL syndrome, and for testing drug candidates to treat it

    Data from: Computational and experimental characterization of dVHL establish a Drosophila model of VHL syndrome

    No full text
    The von Hippel-Lindau (VHL) cancer syndrome is associated with mutations in the VHL gene. The pVHL protein is involved in response to changes in oxygen availability as part of an E3-ligase that targets the Hypoxia-Inducible Factor for degradation. pVHL has a molten globule configuration with marginal thermodynamic stability. The cancer-associated mutations further destabilize it. The Drosophila homolog, dVHL, has relatively low sequence similarity to pVHL, and is also involved in regulating HIF1-Ī±. Using in silico, in vitro and in vivo approaches we demonstrate high similarity between the structure and function of dVHL and pVHL. These proteins have a similar fold, secondary and tertiary structures, as well as thermodynamic stability. Key functional residues in dVHL are evolutionary conserved. This structural homology underlies functional similarity of both proteins, evident by their ability to bind their reciprocal partner proteins, and by the observation that transgenic pVHL can fully maintain normal dVHL-HIF1-Ī± downstream pathways in flies. This novel transgenic Drosophila model is thus useful for studying the VHL syndrome, and for testing drug candidates to treat it

    dVHLModel

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    Coordinate file (PDB format) of the model structure of the Drosophila VHL protein

    The GFP fluorescence signal caused by over-expression of ODD-GFP is lowered by co-expression of either dVHL, pVHL19, or pVHL30.

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    <p>(<b>A</b>) <b>GFP levels</b> were analyzed by confocal microscopy. Genotypes: GMR-Gal4; UAS-ODD-GFP/UAS-RFP (left), GMR-Gal4; UAS-ODD-GFP/UAS-dVHL (second from left) GMR-Gal4; UAS-ODD-GFP/UAS-pVHL19 (third from the left) and GMR-Gal4; UAS-ODD-GFP; UAS-pVHL30 (right). Scale bar, 20 Āµm (<b>B) Western blot</b> analysis showing the levels of ODD-GFP protein extract from flies heads. Ī²-actin was used as loading control. (<b>1</b>) GMR-Gal4; UAS-ODD-GFP/UAS-RFP. (<b>2</b>) GMR-Gal4. (<b>3</b>) GMR-Gal4; UAS-ODD-GFP/UAS-dVHL. (<b>4</b>) GMR-Gal4; UAS-ODD-GFP/UAS-pVHL19. (<b>5</b>) GMR-Gal4; UAS-ODD-GFP/UAS-pVHL30.</p
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