289 research outputs found

    Kinetics of Steady-state Differentiation and Mapping of Intrathymic-signaling Environments by Stem Cell Transplantation in Nonirradiated Mice

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    Upon thymus entry, thymic-homing progenitors undergo distinct phases of differentiation as they migrate through the cortex to the capsule, suggesting that the signals that induce these differentiation steps may be stratified in corresponding cortical regions. To better define these regions, we transplanted purified stem cells into nonirradiated congenic recipients and followed their differentiation with respect to both tissue location and time. The earliest progenitors (DN1) remained confined to a very narrow region of the cortex for about the first 10 d of intrathymic residence; this region virtually overlaps the sites of thymic entry, suggesting that DN1 cells move very little during this lengthy period of proliferation and lineage commitment. Movement out of this region into the deeper cortex is asynchronous, and corresponds to the appearance of DN2 cells. Differentiation to the DN3 stage correlates with movement across the midpoint of the cortex, indicating that stromal signals that induce functions such as TCR gene rearrangement reside mainly in the outer half of the cortex. The minimum time to reach the capsule, and thus transit to the DP stage, is ∌13 d, with the average time a few days longer. These findings reveal for the first time the kinetics of steady-state progenitor differentiation in the thymus, as well as defining the boundaries of cortical regions that support different phases of the differentiation process. We also show that the first lineage-positive progeny of transplanted stem cells to appear in the thymus are dendritic cells in the medulla, suggesting that each new wave of new T cell production is preceded by a wave of regulatory cells that home to the medulla and ensure efficient tolerance and selection

    Establishing confidence in the output of qualitative research synthesis: the ConQual approach

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    BACKGROUND: The importance of findings derived from syntheses of qualitative research has been increasingly acknowledged. Findings that arise from qualitative syntheses inform questions of practice and policy in their own right and are commonly used to complement findings from quantitative research syntheses. The GRADE approach has been widely adopted by international organisations to rate the quality and confidence of the findings of quantitative systematic reviews. To date, there has been no widely accepted corresponding approach to assist health care professionals and policy makers in establishing confidence in the synthesised findings of qualitative systematic reviews. METHODS: A methodological group was formed develop a process to assess the confidence in synthesised qualitative research findings and develop a Summary of Findings tables for meta-aggregative qualitative systematic reviews. RESULTS: Dependability and credibility are two elements considered by the methodological group to influence the confidence of qualitative synthesised findings. A set of critical appraisal questions are proposed to establish dependability, whilst credibility can be ranked according to the goodness of fit between the author's interpretation and the original data. By following the processes outlined in this article, an overall ranking can be assigned to rate the confidence of synthesised qualitative findings, a system we have labelled ConQual. CONCLUSIONS: The development and use of the ConQual approach will assist users of qualitative systematic reviews to establish confidence in the evidence produced in these types of reviews and can serve as a practical tool to assist in decision making.Zachary Munn, Kylie Porritt, Craig Lockwood, Edoardo Aromataris and Alan Pearso

    Midwives\u27 use of best available evidence in practice: An integrative review

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    Aims and objectives: To synthesise international research that relates to midwives\u27 use of best available evidence in practice settings and identify key issues relating to the translation of latest evidence into everyday maternity care. Background: Midwifery is a research‐informed profession. However, a gap persists in the translation of best available evidence into practice settings, compromising gold standard maternity care and delaying the translation of new knowledge into everyday practice. Design: A five‐step integrative review approach, based on a series of articles published by the Joanna Briggs Institute (JBI) for conducting systematic reviews, was used to facilitate development of a search strategy, selection criteria and quality appraisal process, and the extraction and synthesis of data to inform an integrative review. Methods: The databases CINAHL, MEDLINE, Web of Science, Implementation Science Journal and Scopus were searched for relevant articles. The screening and quality appraisal process complied with the PRISMA 2009 checklist. Narrative analysis was used to develop sub‐categories and dimensions from the data, which were then synthesised to form two major categories that together answer the review question. Results: The six articles reviewed report on midwives\u27 use of best available evidence in Australia, the UK and Asia. Two major categories emerged that confirm that although midwifery values evidence‐based practice (EBP), evidence‐informed maternity care is not always employed in clinical settings. Additionally, closure of the evidence‐to‐practice gap in maternity care requires a multidimensional approach. Conclusion: Collaborative partnerships between midwives and researchers are necessary to initiate strategies that support midwives\u27 efforts to facilitate the timely movement of best available evidence into practice. Relevance to clinical practice: Understanding midwives\u27 use of best available evidence in practice will direct future efforts towards the development of mechanisms that facilitate the timely uptake of latest evidence by all maternity care providers working in clinical settings

    The exposed Mule Creek vent deposits record the structure of a volcanic conduit during a hybrid explosive–effusive eruption

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    Silicic volcanic eruptions commonly begin with the explosive ejection of pyroclastic material, before transitioning to gentler effusion-dominated activity. Well-exposed dissected silicic systems are scarce and poorly studied, hindering the advances in our understanding of the explosive–effusive transition needed to improve interpretations of volcanic unrest and hazard forecasting. The Mule Creek vent (New Mexico, USA) is a dissected silicic conduit that records the processes controlling conduit formation and evolution, and the role tuffisites (fractures filled with variably welded pyroclasts) play in conduit dynamics. Here, we use decimeter-scale photo-mapping of lithostratigraphic units and thin section analysis to differentiate and interpret three dominant emplacement styles during vent evolution. First, there was repeated deposition and erosion of pyroclastic material at the conduit walls, recorded by erosive surfaces in pyroclastic breccia and agglomerates at the conduit margins. Second, sub-vertical domains of dense melt-dominated magma were emplaced and preserved as glass-dominated vitrophyre and brecciated vitrophyre, with the textural hallmarks of assembly from welding of pyroclasts. Finally, the sub-horizontal fracturing of previously deposited lithologies produced laterally cross-cutting tuffisites. The vent deposits track the widening and then narrowing of the conduit through time and reflect progressive insulation and generally higher temperatures towards the conduit center as pyroclasts accumulate. Welding of pyroclastic fill and the formation of dense vitrophyres towards the conduit center lowers deposit porosity and effective wall permeability. This drives localized gas pressure increases and results in gas-driven fracturing, generating tuffisites, which act as transient outgassing pathways. The structure of the Mule Creek vent records an explosive–effusive transition, constraining the processes controlling conduit evolution and aiding our interpretation of volcanic unrest

    Children’s experiences following a CBT intervention to reduce dental anxiety: one year on

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    Objective: To investigate children’s ongoing experiences of dental care and use of strategies to manage their dental anxiety following cognitive behavioural therapy (CBT). Design: A child self-completed postal questionnaire. Settings: Hospital, community and general dental practice. Subjects: Questionnaires were sent to 44 children, aged 10-17 years who had been referred to specialist services due to their dental anxiety. Intervention: Children had all previously received a guided CBT self-help intervention to reduce their dental anxiety and, on completion of treatment, had been discharged to their referring dentist. Questionnaires were sent out 12-18 months later to ascertain dental attendance patterns and application of any strategies learnt from the previous CBT intervention. Results: 22 responses (50%) were received from 16 girls and 6 boys. 82% had subsequently accessed follow up care with a general dental practitioner and over half of these had undergone a dental procedure, other than a check-up. 91% reported feeling less worried about dental visits, than previously, and described a change in cognition, behaviours, and feelings that allowed them to manage their anxiety better. Conclusions: CBT has positive immediate and longitudinal effects in reducing children’s dental anxiety. The challenge of adopting this evidence-based approach within primary care settings remains

    Service evaluation of a nurse-led dental anxiety management service for adult patients

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    Objective: Evaluate patients’ and professionals’ experiences of a Nurse-led Dental Anxiety Management Service (NDAMS). Design: Service evaluation. Setting: The NDAMS operates as part of Sheffield Salaried Primary Dental Care Service. Subjects and methods: Questionnaire survey of anxious patients and qualitative interviews with patients and professionals Interventions: Dental nurses delivered low-level psychological interventions as part of an Integrated Care Pathway (ICP) for dental anxiety. Main outcome Measures: Dental anxiety and oral health-related quality of life (OHRQoL) questionnaires were completed by patients prior to and following NDAM. Results: A total of 187 patients were assessed as suitable for NDAM (mean age= 33.7, 77% female) and 33 had completed it at the time of the service evaluation. Of those patients who had completed the intervention significant improvements in dental anxiety and OHRQoL were reported. Professionals highlighted the importance of integrated working, adequate support and training and assessing the suitability of patients for NDAM. Conclusion: ICPs that combine pharmacological and psychological management approaches can help meet the needs of dentally anxious patients, however, early identification of patients most likely to benefit from psychological intervention should be a priority

    Antecedents and outcomes of consumer environmentally friendly attitudes and behaviour

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    With the intensification of problems relating to the environment, a growing number of consumers are becoming more ecologically conscious in their preferences and purchases of goods. This paper presents the results of a study conducted among 500 Cypriot consumers, focusing on the factors that shape consumer environmental attitudes and behaviour, as well as on the resulting outcomes. The findings confirmed that both the inward and outward environmental attitudes of a consumer are positively influenced by his/her degree of collectivism, long-term orientation, political involvement, deontology, and law obedience, but have no connection with liberalism. The adoption of an inward environmental attitude was also found to be conducive to green purchasing behaviour that ultimately leads to high product satisfaction. On the other hand, an outward environmental attitude facilitates the adoption of a general environmental behaviour, which is responsible for greater satisfaction with life. The findings of the study have important implications for shaping effective company offerings to consumers in target markets, as well as formulating appropriate policies at the governmental level to enhance environmental sensitivity among citizens
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