3,735 research outputs found

    Evaluation of MHOST analysis capabilities for a plate element

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    Results of the evaluation of the static, buckling, and free vibration analyses capabilities of MHOST for the plate elements are presented. Two large scale, general purpose finite element codes (MARC and MSC/NASTRAN) are used to validate MHOST. Comparisons of MHOST results with those from MARC and MSC/NASTRAN show good agreement and indicate that MHOST can be used with confidence to perform the aforementioned analyses using the plate element

    Crowdsourcing Linked Data on listening experiences through reuse and enhancement of library data

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    Research has approached the practice of musical reception in a multitude of ways, such as the analysis of professional critique, sales figures and psychological processes activated by the act of listening. Studies in the Humanities, on the other hand, have been hindered by the lack of structured evidence of actual experiences of listening as reported by the listeners themselves, a concern that was voiced since the early Web era. It was however assumed that such evidence existed, albeit in pure textual form, but could not be leveraged until it was digitised and aggregated. The Listening Experience Database (LED) responds to this research need by providing a centralised hub for evidence of listening in the literature. Not only does LED support search and reuse across nearly 10,000 records, but it also provides machine-readable structured data of the knowledge around the contexts of listening. To take advantage of the mass of formal knowledge that already exists on the Web concerning these contexts, the entire framework adopts Linked Data principles and technologies. This also allows LED to directly reuse open data from the British Library for the source documentation that is already published. Reused data are re-published as open data with enhancements obtained by expanding over the model of the original data, such as the partitioning of published books and collections into individual stand-alone documents. The database was populated through crowdsourcing and seamlessly incorporates data reuse from the very early data entry phases. As the sources of the evidence often contain vague, fragmentary of uncertain information, facilities were put in place to generate structured data out of such fuzziness. Alongside elaborating on these functionalities, this article provides insights into the most recent features of the latest instalment of the dataset and portal, such as the interlinking with the MusicBrainz database, the relaxation of geographical input constraints through text mining, and the plotting of key locations in an interactive geographical browser

    Does metabolic reprogramming underpin age-associated changes in T cell phenotype and function?

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    T cells are required for an effective adaptive immune response. The principal function of T cells is to promote efficient removal of foreign material by identifying and mounting a specific response to nonself. A decline in T cell function in aging is thought to contribute to reduced response to infection and vaccination and an increase in autoimmunity. This may in part be due to the age-related decrease in naïve CD4+ T cells and increase in antigen-experienced CD4+ T cells, loss of redox homeostasis, and impaired metabolic switching. Switching between subsets is triggered by the integration of extracellular signals sensed through surface receptors and the activation of discrete intracellular metabolic pathways. This article explores how metabolic programming and loss of redox homeostasis during aging may contribute to age-associated changes in T cell phenotype and function. © 2014 Elsevier Inc

    Extractables and leachables from poly-ε-caprolactone/phosphate based glass composites

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    In this study poly-ε-caprolactone and iron containing phosphate based glass composites have been investigated in terms of their degradability, structural changes and potential for fracture fixation devices. Any material being used within the body requires Regulary acceptance. A key aspect of this is safety and a toxicological assessment of any extracted or leached species. As a crucial part of the project, PBG fibres were assessed for extractables and leachables. Weight loss was also investigated in order to assess the durability with increasing iron content. The following glass fibre compositions were studied: 50P45Ca5Na, 50P35Ca5Na5Fe and 50P30Ca5Na10Fe. They were then fabricated into composites, with PCL, by compression moulding and stored in pH4 and pH7 buffer, krebs solution, saline solution and water for 78 weeks at 37oC. The resulting composites, and their corresponding solutions, were assessed for extractables and leachables, weight change, pH shifts, porosity and pore size, thermal properties and structural changes. It was demonstrated that the addition of 10%w/w iron into the PBG structure increased the durability by an order of magnitude due to the iron acting as a network former within the P-O-P backbone. The order of leaching was phosphate> sodium> calcium> iron. This was explained by the amount of the oxides originally present in the PBG structure, breakage of the phosphate backbone within the PBG, divalent calcium ions forming chelate cross links which decreases the dissolution rate compared to sodium and Fe-O-P bonds being more resistant to hydration than P-O-P bonds. The weight loss for 50P35Ca5Na10Fe was a third less than the other two PBGs and the weight loss for the equivalent composite was half of the non-iron containing composite. The leaching rate of the 10%w/w iron containing composite was approximately half that of the non-iron containing composite. Unpolymerised caprolactone was observed, alongside 2 oligomers, for the organic leachables from the PCL component of the composites. The density of the PCL/PBG composite was greater than for PCL alone. As iron was added to the PBG, within the composite, it further increased due to the Fe-O-P bonds within the PBG structure which have a dual nature of tetrahedral and octahedral coordination. Differential Scanning Calorimetry (DSC) showed a decrease in crystallinity and glass transition (Tg) when PBG was added to PCL but an increase in melting point due to cross linked density of the PBG network. After storage in aqueous media the crystallinity and Tg increased which could partially be attributed to realignment of the polymer chains within the PCL under storage in aqueous media at 37oC. The amount of iron in the glass structure extended the time for dissolution. Elemental analysis showed that the presence of iron within the composite reduced the leachables rate. Hence, the accumulation of the ions in a local area is lowered due to fewer ions being released over the same time period for iron containing PBG. The leachables were within acceptable toxicological limits and the amount of calcium present (within the PBG) is beneficial for the bone healing process. Hence, this material is suitable for use in a bone fixation device

    ZAP: The role of routine surveillance data in understanding the geography and timing of Salmonella on UK pig farms.

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    The Zoonoses Action Plan (ZAP), at its inception m 2002, sought to reduce prevalence of Salmonella mfection 1n quality assured p1gs at slaughter by 25% within three years. Salmonella levels are monitored by Meat Juice ELISA tests on samples from individual pigs and aggregated to indicate farm-level Salmonella status. By combining the ZAP scheme and quality assurance scheme datasets we generated a large geographically referenced data set which allows us to investigate aspects of the spatial and temporal epidemiology of Salmonella on GB pig farms. We seek in this study to address two questions. First, is there evidence that Salmonella in GB pigs vanes seasonally? Secondly, do close farms tend to have similar levels of Salmonella? We suggest explanations for spatial and temporal effects where evidenced. Knowledge of seasons or GB regions which have atypically high Salmonella risk informs the design of control strategies

    Maternal plasma DHA levels increase prior to 29 days post-LH surge in women undergoing frozen embryo transfer: a prospective, observational study of human pregnancy

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    Context: Docosahexaenoic acid (DHA) is an important fatty acid required for neurological development but its importance during early fetal neurological organogenesis is unknown. Objective: To assess plasma fatty acid changes in early pregnancy in women undergoing natural cycle-frozen embryo transfer as a means of achieving accurately-timed periconceptual sampling. Design: Women undergoing frozen embryo transfer were recruited and serial fasting blood samples were taken pre-luteinising hormone (LH) surge, and at days 18, 29 and 45 post-LH surge and fatty acids were analysed using gas chromatography. Setting: Assisted Conception Unit, Glasgow Royal Infirmary, Scotland Main outcome measures: Plasma fatty acid concentrations, influence of twin pregnancies on DHA plasma concentration. Results: In pregnant women, there was a rapid, early increase in the maternal rate of change of plasma DHA concentration observed by 29 days post-LH surge (mean±SD, from 0.1±1.3 to 1.6±2.9 nmol DHA per mL plasma per day). This early pressure to increase plasma DHA concentration was further emphasised in twin pregnancies where the increase in DHA concentration over 45 days was two-fold higher than in singleton pregnancies (mean±SD increase, 74±39 nmol/mL versus 36±40 nmol/mL). An index of delta-6 desaturase activity increased 30% and positively correlated with the rate of change of DHA concentration between day 18 and 29-post LH surge (R-squared adjusted = 41%, P=0.0002). DHA was the only fatty acid with a continual accelerated increase in plasma concentration and a positive incremental area under the curve (mean±SD, 632±911 nmol/mL x day) over the first 45 days of gestation. Conclusions: An increase in maternal plasma DHA concentration is initiated in human pregnancy prior to neural tube closure which occurs at 28 days' gestation

    Unequal relationships in high and low power distance societies: a comparative study of tutor - student role relations in Britain and China

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    This study investigated people's conceptions of an unequal role relationship in two different types of society: a high power distance society and a low power distance society. The study focuses on the role relationship of tutor and student. British and Chinese tutors and postgraduate students completed a questionnaire that probed their conceptions of degrees of power differential and social distance/closeness in this role relationship. ANOVA results yielded a significant nationality effect for both aspects. Chinese respondents judged the relationship to be closer and to have a greater power differential than did British respondents. Written comments on the questionnaire and interviews with 9 Chinese academics who had experienced both British and Chinese academic environments supported the statistical findings and indicated that there are fundamental ideological differences associated with the differing conceptions. The results are discussed in relation to Western and Asian concepts of leadership and differing perspectives on the compatibility/incompatibility of power and distance/closeness

    Support and performance improvement for primary health care workers in low- and middle-income countries: a scoping review of intervention design and methods.

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    Primary health care workers (HCWs) in low- and middle-income settings (LMIC) often work in challenging conditions in remote, rural areas, in isolation from the rest of the health system and particularly specialist care. Much attention has been given to implementation of interventions to support quality and performance improvement for workers in such settings. However, little is known about the design of such initiatives and which approaches predominate, let alone those that are most effective. We aimed for a broad understanding of what distinguishes different approaches to primary HCW support and performance improvement and to clarify the existing evidence as well as gaps in evidence in order to inform decision-making and design of programs intended to support and improve the performance of health workers in these settings. We systematically searched the literature for articles addressing this topic, and undertook a comparative review to document the principal approaches to performance and quality improvement for primary HCWs in LMIC settings. We identified 40 eligible papers reporting on interventions that we categorized into five different approaches: (1) supervision and supportive supervision; (2) mentoring; (3) tools and aids; (4) quality improvement methods, and (5) coaching. The variety of study designs and quality/performance indicators precluded a formal quantitative data synthesis. The most extensive literature was on supervision, but there was little clarity on what defines the most effective approach to the supervision activities themselves, let alone the design and implementation of supervision programs. The mentoring literature was limited, and largely focused on clinical skills building and educational strategies. Further research on how best to incorporate mentorship into pre-service clinical training, while maintaining its function within the routine health system, is needed. There is insufficient evidence to draw conclusions about coaching in this setting, however a review of the corporate and the business school literature is warranted to identify transferrable approaches. A substantial literature exists on tools, but significant variation in approaches makes comparison challenging. We found examples of effective individual projects and designs in specific settings, but there was a lack of comparative research on tools across approaches or across settings, and no systematic analysis within specific approaches to provide evidence with clear generalizability. Future research should prioritize comparative intervention trials to establish clear global standards for performance and quality improvement initiatives. Such standards will be critical to creating and sustaining a well-functioning health workforce and for global initiatives such as universal health coverage

    Deciphering c-MYC-regulated genes in two distinct tissues.

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    BACKGROUND: The transcription factor MYC is a critical regulator of diverse cellular processes, including both replication and apoptosis. Differences in MYC-regulated gene expression responsible for such opposing outcomes in vivo remain obscure. To address this we have examined time-dependent changes in global gene expression in two transgenic mouse models in which MYC activation, in either skin suprabasal keratinocytes or pancreatic islet β-cells, promotes tissue expansion or involution, respectively. RESULTS: Consistent with observed phenotypes, expression of cell cycle genes is increased in both models (albeit enriched in β-cells), as are those involved in cell growth and metabolism, while expression of genes involved in cell differentiation is down-regulated. However, in β-cells, which unlike suprabasal keratinocytes undergo prominent apoptosis from 24 hours, there is up-regulation of genes associated with DNA-damage response and intrinsic apoptotic pathways, including Atr, Arf, Bax and Cycs. In striking contrast, this is not the case for suprabasal keratinocytes, where pro-apoptotic genes such as Noxa are down-regulated and key anti-apoptotic pathways (such as Igf1-Akt) and those promoting angiogenesis are up-regulated. Moreover, dramatic up-regulation of steroid hormone-regulated Kallikrein serine protease family members in suprabasal keratinocytes alone could further enhance local Igf1 actions, such as through proteolysis of Igf1 binding proteins. CONCLUSIONS: Activation of MYC causes cell growth, loss of differentiation and cell cycle entry in both β-cells and suprabasal keratinocytes in vivo. Apoptosis, which is confined to β-cells, may involve a combination of a DNA-damage response and downstream activation of pro-apoptotic signalling pathways, including Cdc2a and p19(Arf)/p53, and downstream targets. Conversely, avoidance of apoptosis in suprabasal keratinocytes may result primarily from the activation of key anti-apoptotic signalling pathways, particularly Igf1-Akt, and induction of an angiogenic response, though intrinsic resistance to induction of p19(Arf) by MYC in suprabasal keratinocytes may contribute.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    Comparative ergonomic workflow and user experience analysis of MRI versus fluoroscopy-guided vascular interventions:an iliac angioplasty exemplar case study

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    Purpose A methodological framework is introduced to assess and compare a conventional fluoroscopy protocol for peripheral angioplasty with a new magnetic resonant imaging (MRI)-guided protocol. Different scenarios were considered during interventions on a perfused arterial phantom with regard to time-based and cognitive task analysis, user experience and ergonomics. Methods Three clinicians with different expertise performed a total of 43 simulated common iliac angioplasties (9 fluoroscopic, 34 MRI-guided) in two blocks of sessions. Six different configurations for MRI guidance were tested in the first block. Four of them were evaluated in the second block and compared to the fluoroscopy protocol. Relevant stages’ durations were collected, and interventions were audio-visually recorded from different perspectives. A cued retrospective protocol analysis (CRPA) was undertaken, including personal interviews. In addition, ergonomic constraints in the MRI suite were evaluated. Results Significant differences were found when comparing the performance between MRI configurations versus fluoroscopy. Two configurations [with times of 8.56 (0.64) and 9.48 (1.13) min] led to reduce procedure time for MRI guidance, comparable to fluoroscopy [8.49 (0.75) min]. The CRPA pointed out the main influential factors for clinical procedure performance. The ergonomic analysis quantified musculoskeletal risks for interventional radiologists when utilising MRI. Several alternatives were suggested to prevent potential low-back injuries. Conclusions This work presents a step towards the implementation of efficient operational protocols for MRI-guided procedures based on an integral and multidisciplinary framework, applicable to the assessment of current vascular protocols. The use of first-user perspective raises the possibility of establishing new forms of clinical training and education
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