640 research outputs found

    Phytochemical and antimicrobial screening of the crude petroleum spirit and methanol extracts of the stem bark, leaves and roots of Ficus thoningii (blume)

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    Ficus thoningii which has some traditional medicinal uses was investigated. Phytochemical screening of the stem bark, leaves and roots gave positive results for carbohydrates, glycosides, saponins and alkaloids. Antimicrobial screening of the crude petroleum spirit and methanol extracts showed activity against Klebsiella pneumoniae, Staphylococcus aureus, Escherichia coli, Providencia stauti and Bacillus subtilis but no activity was observed against Salmonella typhi. The crude petroleum spiritextracts of the leaves and stem bark of the plant had minimum inhibitory concentrations at 50 mg/ml while the roots had no minimum inhibitory concentration at the test concentration. The crude methanolextracts of the various plant parts showed minimum inhibitory concentration at 50 mg/ml on all the pathogens tested for

    Inter-organisational collaboration enabling care delivery in a specialist cancer surgery provider network: A qualitative study

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    Objective: To explore the processes, challenges and strategies used to govern and maintain inter-organisational collaboration between professionals in a provider network in London, United Kingdom, which implemented major system change focused on the centralisation of specialist cancer surgery. Methods: We used a qualitative design involving interviews with stakeholders (n = 117), non-participant observations (n = 163) and documentary analysis (n = 100). We drew on an existing model of collaboration in healthcare organisations and expanded this framework by applying it to the analysis of collaboration in the context of major system change. Results: Network provider organisations established shared goals, maintained central figures who could create and sustain collaboration, and promoted distributed forms of leadership. Still, organisations continued to encounter barriers or challenges in relation to developing opportunities for mutual acquaintanceship across all professional groups; the active sharing of knowledge, expertise and good practice across the network; the fostering of trust; and creation of information exchange infrastructures fit for collaborative purposes. Conclusion: Collaborative relationships changed over time, becoming stronger post-implementation in some areas, but continued to be negotiated where resistance to the centralisation remained. Future research should explore the sustainability of these relationships and further unpack how hierarchies and power relationships shape inter-organisational collaboration

    Large N Free Energy of 3d N=4 SCFTs and AdS/CFT

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    We provide a non-trivial check of the AdS_4/CFT_3 correspondence recently proposed in arXiv:1106.4253 by verifying the GKPW relation in the large N limit. The CFT free energy is obtained from the previous works (arXiv:1105.2551, arXiv:1105.4390) on the S^3 partition function for 3-dimensional N=4 SCFT T[SU(N)]. This is matched with the computation of the type IIB action on the corresponding gravity background. We unexpectedly find that the leading behavior of the free energy at large N is 1/2 N^2 ln N. We also extend our results to richer theories and argue that 1/2 N^2 ln N is the maximal free energy at large N in this class of gauge theories.Comment: 20 pages, 3 figure

    Centralisation of specialist cancer surgery services in two areas of England: the RESPECT-21 mixed-methods evaluation

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    Background: Centralising specialist cancer surgical services is an example of major system change. High-volume centres are recommended to improve specialist cancer surgery care and outcomes. Objective: Our aim was to use a mixed-methods approach to evaluate the centralisation of specialist surgery for prostate, bladder, renal and oesophago-gastric cancers in two areas of England [i.e. London Cancer (London, UK), which covers north-central London, north-east London and west Essex, and Greater Manchester Cancer (Manchester, UK), which covers Greater Manchester]. Design: Stakeholder preferences for centralising specialist cancer surgery were analysed using a discrete choice experiment, surveying cancer patients (n = 206), health-care professionals (n = 111) and the general public (n = 127). Quantitative analysis of impact on care, outcomes and cost-effectiveness used a controlled before-and-after design. Qualitative analysis of implementation and outcomes of change used a multisite case study design, analysing documents (n = 873), interviews (n = 212) and non-participant observations (n = 182). To understand how lessons apply in other contexts, we conducted an online workshop with stakeholders from a range of settings. A theory-based framework was used to synthesise these approaches. Results: Stakeholder preferences – patients, health-care professionals and the public had similar preferences, prioritising reduced risk of complications and death, and better access to specialist teams. Travel time was considered least important. Quantitative analysis (impact of change) – only London Cancer’s centralisations happened soon enough for analysis. These changes were associated with fewer surgeons doing more operations and reduced length of stay [prostate –0.44 (95% confidence interval –0.55 to –0.34) days; bladder –0.563 (95% confidence interval –4.30 to –0.83) days; renal –1.20 (95% confidence interval –1.57 to –0.82) days]. The centralisation meant that renal patients had an increased probability of receiving non-invasive surgery (0.05, 95% confidence interval 0.02 to 0.08). We found no evidence of impact on mortality or re-admissions, possibly because risk was already low pre-centralisation. London Cancer’s prostate, oesophago-gastric and bladder centralisations had medium probabilities (79%, 62% and 49%, respectively) of being cost-effective, and centralising renal services was not cost-effective (12% probability), at the £30,000/quality-adjusted life-year threshold. Qualitative analysis, implementation and outcomes – London Cancer’s provider-led network overcame local resistance by distributing leadership throughout the system. Important facilitators included consistent clinical leadership and transparent governance processes. Greater Manchester Cancer’s change leaders learned from history to deliver the oesophago-gastric centralisation. Greater Manchester Cancer’s urology centralisations were not implemented because of local concerns about the service model and local clinician disengagement. London Cancer’s network continued to develop post implementation. Consistent clinical leadership helped to build shared priorities and collaboration. Information technology difficulties had implications for interorganisational communication and how reliably data follow the patient. London Cancer’s bidding processes and hierarchical service model meant that staff reported feelings of loss and a perceived ‘us and them’ culture. Workshop – our findings resonated with workshop attendees, highlighting issues about change leadership, stakeholder collaboration and implications for future change and evaluation. Limitations: The discrete choice experiment used a convenience sample, limiting generalisability. Greater Manchester Cancer implementation delays meant that we could study the impact of only London Cancer changes. We could not analyse patient experience, quality of life or functional outcomes that were important to patients (e.g. continence). Future research: Future research may focus on impact of change on care options offered, patient experience, functional outcomes and long-term sustainability. Studying other approaches to achieving high-volume services would be valuable. Study registration: ational Institute for Health and Care Research (NIHR) Clinical Research Network Portfolio reference 19761

    Continuation for thin film hydrodynamics and related scalar problems

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    This chapter illustrates how to apply continuation techniques in the analysis of a particular class of nonlinear kinetic equations that describe the time evolution through transport equations for a single scalar field like a densities or interface profiles of various types. We first systematically introduce these equations as gradient dynamics combining mass-conserving and nonmass-conserving fluxes followed by a discussion of nonvariational amendmends and a brief introduction to their analysis by numerical continuation. The approach is first applied to a number of common examples of variational equations, namely, Allen-Cahn- and Cahn-Hilliard-type equations including certain thin-film equations for partially wetting liquids on homogeneous and heterogeneous substrates as well as Swift-Hohenberg and Phase-Field-Crystal equations. Second we consider nonvariational examples as the Kuramoto-Sivashinsky equation, convective Allen-Cahn and Cahn-Hilliard equations and thin-film equations describing stationary sliding drops and a transversal front instability in a dip-coating. Through the different examples we illustrate how to employ the numerical tools provided by the packages auto07p and pde2path to determine steady, stationary and time-periodic solutions in one and two dimensions and the resulting bifurcation diagrams. The incorporation of boundary conditions and integral side conditions is also discussed as well as problem-specific implementation issues

    A family of key agreement mechanisms for mission critical communications for secure mobile ad hoc and wireless mesh internetworking

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    Future wireless networks like mobile ad hoc networks and wireless mesh networks are expected to play important role in demanding communications such as mission critical communications. MANETs are ideal for emergency cases where the communication infrastructure has been completely destroyed and there is a need for quick set up of communications among the rescue/emergency workers. In such emergency scenarios wireless mesh networks may be employed in a later phase for providing advanced communications and services acting as a backbone network in the affected area. Internetworking of both types of future networks will provide a broad range of mission critical applications. While offering many advantages, such as flexibility, easy of deployment and low cost, MANETs and mesh networks face important security and resilience threats, especially for such demanding applications. We introduce a family of key agreement methods based on weak to strong authentication associated with several multiparty contributory key establishment methods. We examine the attributes of each key establishment method and how each method can be better applied in different scenarios. The proposed protocols support seamlessly both types of networks and consider system and application requirements such as efficient and secure internetworking, dynamicity of network topologies and support of thin clients. © 2011 Ioannis G. Askoxylakis et al

    Diagnostic accuracy of consensus diagnostic criteria for frontotemporal dementia in a memory clinic population

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    Background/Aims: The goal of the present study was to evaluate the diagnostic accuracy of the core diagnostic criteria for frontotemporal dementia (FTD) [Neary D, et al: Neurology 1998;51:1546-1554] within a memory clinic population. Methods: The 5 core diagnostic criteria for FTD were operationalised in an informant-based written questionnaire. For a diagnosis of FTD the total clinical picture was weighted with findings on additional investigations and possible exclusion criteria, with follow-up of at least 1 year. Results: The operationalised core criteria for FTD had a sensitivity of 79% (95% CI = 57-92) and a specificity of 90% (95% CI = 85-94). Conclusion: The core diagnostic criteria for FTD applied in a caregiver questionnaire have good diagnostic accuracy among subjects without advanced dementia attending a memory clinic. This stresses the importance of the informant-based history in the differential diagnosis of dementia. Copyrigh

    Establishment of LIF-Dependent Human iPS Cells Closely Related to Basic FGF-Dependent Authentic iPS Cells

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    Human induced pluripotent stem cells (iPSCs) can be divided into a leukemia inhibitory factor (LIF)-dependent naïve type and a basic fibroblast growth factor (bFGF)-dependent primed type. Although the former are more undifferentiated than the latter, they require signal transduction inhibitors and sustained expression of the transgenes used for iPSC production. We used a transcriptionally enhanced version of OCT4 to establish LIF-dependent human iPSCs without the use of inhibitors and sustained transgene expression. These cells belong to the primed type of pluripotent stem cell, similar to bFGF-dependent iPSCs. Thus, the particular cytokine required for iPSC production does not necessarily define stem cell phenotypes as previously thought. It is likely that the bFGF and LIF signaling pathways converge on unidentified OCT4 target genes. These findings suggest that our LIF-dependent human iPSCs could provide a novel model to investigate the role of cytokine signaling in cellular reprogramming
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