1,326 research outputs found

    The NBS Cord Time Sharing System

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    Computer with on-line remote device time-sharing, and command system

    Sucrose density gradient centrifugation and cross-flow filtration methods for the production of arbovirus antigens inactivated by binary ethylenimine

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    BACKGROUND: Sucrose density gradient centrifugation and cross-flow filtration methods have been developed and standardised for the safe and reproducible production of inactivated arbovirus antigens which are appropriate for use in diagnostic serological applications. METHODS: To optimise the maximum titre of growth during the propagation of arboviruses, the multiplicity of infection and choice of cell line were investigated using stocks of Ross River virus and Barmah Forest virus grown in both mosquito and mammalian cell lines. To standardise and improve the efficacy of the inactivation of arboviral suspensions, stocks of Ross River virus, Barmah Forest virus, Japanese encephalitis virus, Murray Valley encephalitis virus and Alfuy virus were chemically inactivated using binary ethylenimine at a final concentration of 3 mM. Aliquots were then taken at hourly intervals and crude inactivation rates were determined for each virus using a plaque assay. To ensure complete inactivation, the same aliquots were each passaged 3 times in Aedes albopictus C6/36 cells and the presence of viral growth was detected using an immunofluorescent assay. For larger quantities of viral suspensions, centrifugation on an isopycnic sucrose density gradient or cross-flow filtration was used to produce concentrated, pure antigens or partially concentrated, semi-purified antigens respectively. RESULTS: The results of the propagation experiments suggested that the maximum viral titres obtained for both Ross River virus and Barmah Forest virus were affected by the incubation period and choice of cell line, rather than the use of different multiplicity of infection values. Results of the binary ethylenimine inactivation trial suggested that standardised periods of 5 or 8 hours would be suitable to ensure effective and complete inactivation for a number of different arboviral antigens. CONCLUSION: Two methods used to prepare inactivated arbovirus antigens have been standardised to minimise production failure and expenditure and to provide reagents that conform to the highest quality and safety requirements of a diagnostic serology laboratory. The antigens are suitable for use in either enzyme linked immunosorbent assays or haemagglutination inhibition assays and the optimised protocols can be directly applied to produce antigens from new or emerging arboviral pathogens

    Transcriptional regulation of the urokinase receptor (u-PAR) - A central molecule of invasion and metastasis

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    The phenomenon of tumor-associated proteolysis has been acknowledged as a decisive step in the progression of cancer. This short review focuses on the urokinase receptor (u-PAR), a central molecule involved in tumor-associated invasion and metastasis, and summarizes the transcriptional regulation of u-PAR. The urokinase receptor (u-PAR) is a heavily glycosylated cell surface protein and binds the serine protease urokinase specifically and with high affinity. It consists of three similar cysteine-rich repeats and is anchored to the cell membrane via a GPI-anchor. The u-PAR gene comprises 7 exons and is located on chromosome 19q13. Transcriptional activation of the u-PAR promoter region can be induced by binding of transcription factors (Sp1, AP-1, AP-2, NF-kappaB). One current study gives an example for transcriptional downregulation of u-PAR through a PEA3/ets transcriptional silencing element. Knowledge of the molecular regulation of this molecule in tumor cells could be very important for diagnosis and therapy in the near future

    A Bose-Einstein Approach to the Random Partitioning of an Integer

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    Consider N equally-spaced points on a circle of circumference N. Choose at random n points out of NN on this circle and append clockwise an arc of integral length k to each such point. The resulting random set is made of a random number of connected components. Questions such as the evaluation of the probability of random covering and parking configurations, number and length of the gaps are addressed. They are the discrete versions of similar problems raised in the continuum. For each value of k, asymptotic results are presented when n,N both go to infinity according to two different regimes. This model may equivalently be viewed as a random partitioning problem of N items into n recipients. A grand-canonical balls in boxes approach is also supplied, giving some insight into the multiplicities of the box filling amounts or spacings. The latter model is a k-nearest neighbor random graph with N vertices and kn edges. We shall also briefly consider the covering problem in the context of a random graph model with N vertices and n (out-degree 1) edges whose endpoints are no more bound to be neighbors

    Prolonged low flow reduces reactive hyperemia and augments low flow mediated constriction in the brachial artery independent of the menstrual cycle

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    © 2013 Rakobowchuk et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Non-invasive forearm ischemia-reperfusion injury and low flow induced vascular dysfunction models provide methods to evaluate vascular function. The role of oestrogen, an endogenous anti-oxidant on recovery from ischemia-reperfusion injury has not been evaluated nor has the impact of prolonged low flow on vascular function been established. Eight healthy women (33610 yr) attended the lab during the follicular, ovulatory and mid-luteal phases of their menstrual cycles. After 30 minutes of rest, brachial artery vascular function was assessed by ultrasound measurements of diameter changes during 5 minutes of forearm ischemia and 3 minutes after. Subsequently, a 20-minute forearm ischemia period was completed. Further, vascular function assessments were completed 15, 30 and 45 minutes into recovery. Flow-mediated dilation, lowflow-mediated constriction, and reactive hyperaemia proximal to the area of ischemia were determined. Flow-mediated dilation was reduced at 15 minutes of recovery but recovered at 30 and 45 minutes (PRE: 7.161.0%, POST15:4.560.6%, POST30:5. 560.7% POST45:5.960.4%, p,0.01). Conversely, low-flow mediated constriction increased (PRE: 21.360.4%, POST15: 23.360.6%, POST30: 22.560.5% POST45: 21.560.12%, p,0.01). Reactive hyperaemia was reduced throughout recovery (p,0.05). Data were unaffected by menstrual phase. Prolonged low flow altered vascular function and may relate as much to increased vasoconstriction as with decreased vasodilation. Reductions in anterograde shear and greater retrograde shear likely modulate the brachial artery response, but the reduced total shear also plays an important role. The data suggest substantial alterations in vascular function proximal to areas of ischemia with potential clinical implications following reperfusion.British Heart Foundation (PG/08/060/25340),a Physiological Society summer studentship to SG, and a Wellcome Trust Vacation Studentship to EP

    Range-wide assessment of livestock grazing across the sagebrush biome

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    Domestic livestock grazing occurs in virtually all sagebrush habitats and is a prominent disturbance factor. By affecting habitat condition and trend, grazing influences the resources required by, and thus, the distribution and abundance of sagebrush-obligate wildlife species (for example, sage-grouse Centrocercus spp.). Yet, the risks that livestock grazing may pose to these species and their habitats are not always clear. Although livestock grazing intensity and associated habitat condition may be known in many places at the local level, we have not yet been able to answer questions about use, condition, and trend at the landscape scale or at the range-wide scale for wildlife species. A great deal of information about grazing use, management regimes, and ecological condition exists at the local level (for individual livestock management units) under the oversight of organizations such as the Bureau of Land Management (BLM). However, the extent, quality, and types of existing data are unknown, which hinders the compilation, mapping, or analysis of these data. Once compiled, these data may be helpful for drawing conclusions about rangeland status, and we may be able to identify relationships between those data and wildlife habitat at the landscape scale

    Complete coding sequence of a case of chikungunya virus imported into Australia

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    A case of chikungunya virus infection was imported from India into Australia in late 2016. Infection was diagnosed by real-time reverse transcription-PCR and confirmed by culture isolation and genome sequencing. Phylogenetic analysis of the genome sequence indicated that the virus grouped with the east/central/south African genotype

    From evidence to action: applying gender mainstreaming to pay gaps in the Welsh public sector

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    Progress on reducing gender disparities remains painfully slow, despite efforts to identify the determinants of gender pay gaps and specify size and shape. Recent studies highlight the need for a more nuanced account of the way that public policy shapes organizational responses and insights into the types of organizational practices that diminish pay disparities. In response, this research reports on an action research intervention in three large Welsh public organizations, subject to a unique statutory equality duty. Data demonstrate how an evidence‐based gender mainstreaming approach facilitated the development of a ‘no blame’ strategy, which legitimized organizational proactivity through collaborative and empowering change management processes. The research contributes to the study of gender pay gaps by demonstrating that gender mainstreaming, with facilitative local conditions and supportive public policy, shapes action on gender segregation, with particular success in women's low‐paid employment. Conclusions highlight theoretical and policy implications arising from the research

    The New Media Writing Prize Special Collection

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    This article introduces the New Media Writing Prize (NMWP) special collection (https://www.webarchive.org.uk/en/ukwa/collection/2912) created on behalf of the six UK Legal Deposit Libraries and hosted by the UK Web Archive. It is divided into two sections, presenting the perspectives of the archivists and the organizers of the prize respectively. The first section outlines the scope of the collection and how it fits within the wider collecting activities of the libraries. It explains the methodology and workflows behind building the collection, with a special focus on the quality assurance aspect of the process, and on what constitutes a ‘good copy’ in the context of complex digital narratives. Furthermore, it touches on the history of the collaborations between the British Library and digital writing communities, which resulted in numerous workshops, events, residencies and ultimately the creation of this collection. The second section presents the history of the Prize from the point of view of its organizers, highlighting its evolution through the years and plans for the future
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