1,489 research outputs found

    Near-monochromatic tuneable cryogenic niobium electron field emitter

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    Creating, manipulating, and detecting coherent electrons is at the heart of future quantum microscopy and spectroscopy technologies. Leveraging and specifically altering the quantum features of an electron beam source at low temperatures can enhance its emission properties. Here, we describe electron field emission from a monocrystalline, superconducting niobium nanotip at a temperature of 5.9 K. The emitted electron energy spectrum reveals an ultra-narrow distribution down to 16 meV due to tunable resonant tunneling field emission via localized band states at a nano-protrusion's apex and a cut-off at the sharp low-temperature Fermi-edge. This is an order of magnitude lower than for conventional field emission electron sources. The self-focusing geometry of the tip leads to emission in an angle of 3.7 deg, a reduced brightness of 3.8 x 10exp8 A/(m2 sr V), and a stability of hours at 4.1 nA beam current and 69 meV energy width. This source will decrease the impact of lens aberration and enable new modes in low-energy electron microscopy, electron energy loss spectroscopy, and high-resolution vibrational spectroscopy.Comment: to be published in Phys. Rev. Lett. (2022

    Localization of DIR1 at the tissue, cellular and subcellular levels during Systemic Acquired Resistance in Arabidopsis using DIR1:GUS and DIR1:EGFP reporters

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    <p>Abstract</p> <p>Background</p> <p>Systemic Acquired Resistance (SAR) is an induced resistance response to pathogens, characterized by the translocation of a long-distance signal from induced leaves to distant tissues to prime them for increased resistance to future infection. DEFECTIVE in INDUCED RESISTANCE 1 (DIR1) has been hypothesized to chaperone a small signaling molecule to distant tissues during SAR in <it>Arabidopsis</it>.</p> <p>Results</p> <p>DIR1 promoter:DIR1-GUS/<it>dir1-1 </it>lines were constructed to examine DIR1 expression. DIR1 is expressed in seedlings, flowers and ubiquitously in untreated or mock-inoculated mature leaf cells, including phloem sieve elements and companion cells. Inoculation of leaves with SAR-inducing avirulent or virulent <it>Pseudomonas syringae </it>pv <it>tomato </it>(<it>Pst</it>) resulted in Type III Secretion System-dependent suppression of DIR1 expression in leaf cells. Transient expression of fluorescent fusion proteins in tobacco and intercellular washing fluid experiments indicated that DIR1's ER signal sequence targets it for secretion to the cell wall. However, DIR1 expressed without a signal sequence rescued the <it>dir1-1 </it>SAR defect, suggesting that a cytosolic pool of DIR1 is important for the SAR response.</p> <p>Conclusions</p> <p>Although expression of DIR1 decreases during SAR induction, the protein localizes to all living cell types of the vasculature, including companion cells and sieve elements, and therefore DIR1 is well situated to participate in long-distance signaling during SAR.</p

    Toward a conceptual framework of emotional relationship marketing: an examination of two UK political parties

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    The purpose of this paper is to review the notion of branding and evaluate its applicability to political parties. As ideological politics is in decline, branding may provide a consistent narrative where voters feel a sense of warmth and belonging. The paper aims to build an understanding of the complexity of building a political brand where a combination of image, logo, leadership, and values can all contribute to a compelling brand narrative. It investigates how competing positive and negative messages attempt to build and distort the brand identity. A critical review of bran ding, relationship marketing, and political science literature articulates the conceptual development of branding and its applicability to political parties. The success or failure of negative campaigning is due to the authenticity of a political party’s brand values — creating a coherent brand story — if there is no distance between the brand values articulated by the political party and the values their community perceives then this creates an "authentic" brand. However, if there is a gap this paper illustrates how negative campaigning can be used to build a "doppelganger brand," which undermines the credibility of the authentic political brand. The paper argues that political parties need to understand how brand stories are developed but also how they can be used to protect against negative advertising. This has implications for political marketing strategists and political parties. This paper draws together branding theory and relationship marketing and incorporates them into a framework that makes a contribution to the political marketing literature

    Orthology Analysis and In Vivo Complementation Studies to Elucidate the Role of DIR1 during Systemic Acquired Resistance in Arabidopsis thaliana and Cucumis sativus

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    AtDIR1 (Defective in Induced Resistance1) is an acidic lipid transfer protein essential for systemic acquired resistance (SAR) in Arabidopsis thaliana. Upon SAR induction, DIR1 moves from locally infected to distant uninfected leaves to activate defense priming; however, a molecular function for DIR1 has not been elucidated. Bioinformatic analysis and in silico homology modeling identified putative AtDIR1 orthologs in crop species, revealing conserved protein motifs within and outside of DIR1’s central hydrophobic cavity. In vitro assays to compare the capacity of recombinant AtDIR1 and targeted AtDIR1-variant proteins to bind the lipophilic probe TNS (6,P-toluidinylnaphthalene-2-sulfonate) provided evidence that conserved leucine 43 and aspartic acid 39 contribute to the size of the DIR1 hydrophobic cavity and possibly hydrophobic ligand binding. An Arabidopsis–cucumber SAR model was developed to investigate the conservation of DIR1 function in cucumber (Cucumis sativus), and we demonstrated that phloem exudates from SAR-induced cucumber rescued the SAR defect in the Arabidopsis dir1-1 mutant. Additionally, an AtDIR1 antibody detected a protein of the same size as AtDIR1 in SAR-induced cucumber phloem exudates, providing evidence that DIR1 function during SAR is conserved in Arabidopsis and cucumber. In vitro TNS displacement assays demonstrated that recombinant AtDIR1 did not bind the SAR signals azelaic acid (AzA), glycerol-3-phosphate or pipecolic acid. However, recombinant CsDIR1 and CsDIR2 interacted weakly with AzA and pipecolic acid. Bioinformatic and functional analyses using the Arabidopsis–cucumber SAR model provide evidence that DIR1 orthologs exist in tobacco, tomato, cucumber, and soybean, and that DIR1-mediated SAR signaling is conserved in Arabidopsis and cucumber

    Ageing in Extra Care Housing: Preparation, Persistence and Self-Management at the Boundary Between the Third and Fourth Age

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    Extra care housing (ECH) has been hailed as a potential solution to some of the problems associated with traditional forms of social care, since it allows older people to live independently, while also having access to care and support if required. However, little longitudinal research has focused on the experiences of residents living in ECH, particularly in recent years. This paper reports on a longitudinal study of four ECH schemes in the United Kingdom (UK). Older residents living in ECH were interviewed four times over a two-year period to examine how changes in their care needs were encountered and negotiated by care workers, managers, and residents themselves. This paper focuses on how residents managed their own changing care needs within the context of ECH. Drawing upon theories of the third and fourth age, the paper makes two arguments. First, that transitions across the boundary between the third and fourth age are not always straightforward or irreversible and, moreover, can sometimes be resisted, planned-for, and managed by older people. Second, that operational practices within ECH schemes can function to facilitate or impede residents’ attempts to manage this boundary

    Outcomes-based Commissioning For Social Care in Extra Care Housing: Is There a Future?

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    Purpose: This paper provides an overview of the process of commissioning adult social care services in England. It reflects the literature on commissioning at the strategic level followed by a section on operational or micro-commissioning. The rest of the paper focuses on the emergence of ideas about outcomes based commissioning(OBC)in the field of adult social care and ends with critical consideration of the effectiveness of OBC in adult social care as applied to support and care provided in extra care housing. Design/methodology/approach: The review of strategic and operational commissioning in adult social care in England(and Scotland in brief)is based on both policy documents and a review of the literature,as are the sources addressing outcomes based commissioning in adult social care particularly in extra care housing settings. Findings: The core of this paper focuses on the challenges to the implementation of OBC in adult social care in the context of provision for residents in extra care housing. Of central importance are the impact of the squeeze on funding,increasing costs as a result of demographic change and the introduction of a national living wage plus the focus on the needs of service users through the idea of person-centred care and resistance to change on the part of adult social care staff and workers in pther relevant settings. Originality/value: Addressing the implementation of OBC in adult social care in England in the context of extra care housing

    Can Extra Care Housing support the changing needs of older people living with dementia?

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    With over two thirds of people with dementia living in the community and one third of those living alone, it is important to consider the future housing needs of this population, particularly as symptoms of cognitive impairment increase. Policy in England has focused on enabling people living with dementia to remain in their own homes for as long as possible, often with the support of a family carer. However, many people struggle to maintain an acceptable quality of life in their own homes as their dementia advances, often due to the design limitations of mainstream housing and the challenge of finding specialist domiciliary care that is affordable and of sufficient quality. Extra care housing (ECH) offers a model that aims to support older people living in their own apartments, while also offering specialist person-centred care as and when it is needed. This paper reports on a longitudinal project that explored how ECH can respond to the changing social care needs of residents, including those living with dementia. Participants included residents and staff from four ECH schemes, one of which was a specialist dementia scheme, in two regions of England. Interviews were carried with 51 residents across 4 rounds at 5 month intervals between October 2015 and June 2017. Interviews were also carried out with 7 managers, 20 care staff and 2 local authority commissioners of housing for older people. Key factors included person-centred care and support, flexible commissioning and staffing, appropriate design of the environment and suitable location of the scheme within the wider community. The challenge of delivering services that addresses these issues during a period of reduced public spending is acknowledged. Further research is suggested to compare different approaches to supporting people with dementia, including integrated and separated accommodation, and different stages of dementia

    The In Vitro, Ex Vivo, and In Vivo Effect of Polymer Hydrophobicity on Charge-Reversible Vectors for Self-Amplifying RNA

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    RNA technology has the potential to revolutionize vaccination. However, the lack of clear structure-property relationships in relevant biological models mean there is no clear consensus on the chemical motifs necessary to improve RNA delivery. In this work, we describe the synthesis of a series of copolymers based on the self-hydrolyzing charge-reversible polycation poly(dimethylaminoethyl acrylate) (pDMAEA), varying the lipophilicity of the additional co-monomers. All copolymers formed stable polyplexes, showing efficient complexation with model nucleic acids from nitrogen/phosphate (N/P) ratios of N/P = 5, with more hydrophobic complexes exhibiting slower charge reversal and disassembly compared to hydrophilic analogues. The more hydrophobic copolymers outperformed hydrophilic versions, homopolymer controls and the reference standard polymer (polyethylenimine), in transfection assays on 2D cell monolayers, albeit with significantly higher toxicities. Similarly, hydrophobic derivatives displayed up to a 4-fold higher efficacy in terms of the numbers of cells expressing green fluorescent protein (GFP+) cells in ex vivo human skin (10%) compared to free RNA (2%), attributed to transfection enrichment in epithelial cells. In contrast, in a mouse model, we observed the reverse trend in terms of RNA transfection, with no observable protein production in more hydrophobic analogues, whereas hydrophilic copolymers induced the highest transfection in vivo. Overall, our results suggest an important relationship between the vector lipophilicity and RNA transfection in vaccine settings, with polymer biocompatibility potentially a key parameter in effective in vivo protein production

    Ornithine-derived oligomers and dendrimers forin vitrodelivery of DNA andex vivotransfection of skin cellsviasaRNA

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    © The Royal Society of Chemistry 2020. Gene therapies are undergoing a renaissance, primarily due to their potential for applications in vaccination for infectious diseases and cancers. Although the biology of these technologies is rapidly evolving, delivery strategies need to be improved to overcome the poor pharmacokinetics and cellular transport of nucleic acids whilst maintaining patient safety. In this work, we describe the divergent synthesis of biodegradable cationic dendrimers based on the amino acid ornithine as non-viral gene delivery vectors and evaluate their potential as delivery vectors for DNA and RNA. The dendrimers effectively complexed model nucleic acids at lower N/P ratios than polyethyleneimine and outperformed it in DNA transfection experiments with ratios above 5. Remarkably, all dendrimer polyplexes at N/P = 2 achieved up to 7-fold higher protein content over an optimized PEI formulation when used for transfections with self-amplifying RNA (saRNA). Finally, transfection studies utilizing human skin explants revealed an increase of cells producing protein from 2% with RNA alone to 12% with dendrimer polyplexes, attributed to expression enrichment predominantly in epithelial cells, fibroblasts and leukocytes, with minor enrichment in NK cells, T cells, monocytes, and B cells. Overall, this study indicates the clear potential of ornithine dendrimers as safe and effective delivery vectors for both DNA and RNA therapeutics

    Using longitudinal qualitative research to explore extra care housing

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    Purpose: The process of individual ageing in the context of a care environment is marked by continuity and change. It is shaped by individual, health-related factors as well as by diverse social and environmental factors, including characteristics of the places where older people live. The aim of this paper was to explore how longitudinal qualitative research, as a research method, could be used to explore older people’s changing care needs. Methods: The study used a longitudinal design to examine how the care and support needs of residents and their expectations of services developed over time and how these were influenced by changes in the organisation of their housing as well as in the make-up of the resident population. Residents were interviewed on four occasions over twenty months. Results: The study highlighted the complex ways in which some participants proactively managed the care and support they received, which we argue would have been difficult to discern through other methods. Conclusion: The study adds to the growing evidence base that supports the use of qualitative longitudinal research, the approach enables the researcher to capture the diverse and mutable nature of older people’s experiences at a time of profound change in their lives
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