1,204 research outputs found

    Electrochemical Sensing and Characterization of Aerobic Marine Bacterial Biofilms on Gold Electrode Surfaces

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    Reliable and accurate in situ sensors capable of detecting and quantifying troublesome marine biofilms on metallic surfaces are increasingly necessary. A 0.2 mm diameter gold electrochemical sensor was fully characterized using cyclic voltammetry in abiotic and biotic artificial seawater media within a continuous culture flow cell to detect the growth and development of an aerobic Pseudoalteromonas sp. biofilm. Deconvolution of the abiotic and biotic responses enable the constituent extracellular electron transfer and biofilm responses to be resolved. Differentiation of enhanced oxygen reduction kinetics within the aerobic bacterial biofilm is linked to enzyme and redox mediator activities

    Marine corrosion performance of copper alloy UNS C69100

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    Tungum alloy (UNS C69100) is an aluminum-nickel-silicon brass and is reported to have a good corrosion performance in marine environments (fully wetted, splash zone and atmospheric conditions). In order to gain an in-depth understanding of the marine corrosion performance of this alloy, electrochemical test methods including open-circuit potential, electrochemical impedance spectroscopy, potentiodynamic polarization, and zero-resistance ammetry were used for corrosion investigation of UNS C69100 in a 3.5 wt.% sodium chloride aqueous testing solution, in combination with optical microscopy and scanning electron microscopy. The corrosion properties of UNS C69100 obtained by electrochemical methods were also compared with six alternative alloys: UNS S31603, UNS S31254, UNS S32750, UNS N04400, UNS N08904 and UNS C36000. Galvanic coupling behavior of wrought UNS C69100 bar and seamless tubing against these six alloys in a 3.5% NaCl solution for 30 days immersion are also reported in this paper

    The biosocial event : responding to innovation in the life sciences

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    Innovation in the life sciences calls for reflection on how sociologies separate and relate life processes and social processes. To this end we introduce the concept of the ‘biosocial event’. Some life processes and social processes have more mutual relevance than others. Some of these relationships are more negotiable than others. We show that levels of relevance and negotiability are not static but can change within existing relationships. Such changes, or biosocial events, lie at the heart of much unplanned biosocial novelty and much deliberate innovation. We illustrate and explore the concept through two examples – meningitis infection and epidemic, and the use of sonic ‘teen deterrents’ in urban settings. We then consider its value in developing sociological practice oriented to critically constructive engagement with innovation in the life sciences

    Expression of Mcm2, geminin and Ki67 in normal oral mucosa, oral epithelial dysplasias and their corresponding squamous-cell carcinomas

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    Proteins necessary for the normal regulation of the cell cycle include minichromosome maintenance protein 2 (Mcm2) and geminin. These are overexpressed in several premalignant and malignant tumours. The Mcm2/Ki67 ratio can be used to estimate the population of cells that are in early G1 (licensed to proliferate), and the geminin/Ki67 ratio can determine the relative length of G1. A high ratio indicates a short G1 and a high rate of cell proliferation. Mcm2 and geminin have been scarcely explored in oral epithelial dysplasia (OED) and oral squamous-cell carcinoma (OSCC). The purpose of this study was to identify the expression pattern of Mcm2, Ki67 and geminin in normal oral mucosa (NOM), OED and their subsequent OSCC, to determine if expression could help predict the prognosis of OED. Paraffin sections of 41 OED cases that progressed to carcinoma, 40 OED without malignant progression, 38 OSCC and 15 NOM were immunostained with antibodies against Mcm2, geminin and Ki67. Labelling indices (LIs) increased progressively from NOM, OED and OSCC (Mcm2, Po0.001; geminin, Po0.001 and Ki67, Po0.001). In all the OED cases (n ¼ 81) the levels of expression of Mcm2 (LI, 73.6), geminin (LI, 24.4) and Ki67 (LI, 44.5) were elevated indicating a constant cellcycle re-entry. When the OED groups were compared, Mcm2 protein expression was higher in the OED with malignant progression (P ¼ 0.04), likewise there was a significant increase in the Mcm2/Ki67 and geminin/Ki67 ratios (P ¼ 0.04 and 0.02 respectively). Mcm2 and geminin proteins seem to be novel biomarkers of growth and may be useful prognostic tools for OED

    DNA replication licensing and cell cycle kinetics of oligodendroglial tumours

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    The convergence point of growth-signalling pathways that control cell proliferation is the initiation of genome replication, the core of which is the assembly of pre-replicative complexes (pre-RCs), resulting in chromatin being ‘licensed’ for DNA replication in the subsequent S phase. The Mcm2–7 complex is a core constituent of the pre-RC, whose recruitment to replication origins is dependent on the Cdt1 loading factor. Geminin is a potent inhibitor of the initiation of DNA replication by preventing Mcm2–7 assembly at origins via its interaction with Cdt1, ensuring genomic integrity through suppression of re-initiation events in S phase. Here we investigate the regulation of Ki67, Mcm2, p21, caspase 3 and Geminin in a series of 55 oligodendrogliomas to provide an integrated picture of how cellular proliferation and programmed cell death are dysregulated in these tumours. Geminin does not behave as an inhibitor of cell proliferation, its labelling index rising with increasing growth fraction as defined by Ki67 or Mcm2 expression. Geminin is expressed in a higher proportion of cells in higher grade tumours (P<0.001) and shows a strong correlation to proliferation and replication licensing (P<0.01), but not apoptosis. Increasing tumour anaplasia is not associated with loss of Geminin. Importantly, the G1 phase of the proliferative cell cycle, as assessed by the Geminin/Ki67 ratio, shortens with increasing anaplasia, providing new potential algorithms for prognostic assessment. Origin licensing proteins thus provide powerful novel tools for assessment of tumour cell cycle kinetics in routinely processed surgical biopsy material

    Academic doctors' views of complementary and alternative medicine (CAM) and its role within the NHS: an exploratory qualitative study

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    <p>Abstract</p> <p>Background</p> <p>There has been a marked increase in the use of complementary and alternative medicine (CAM) in the UK population in recent years. Surveys of doctors' perspectives on CAM have identified a variety of views and potential information needs. While these are useful for describing the proportions of doctors who hold particular attitudes towards CAM, they are less helpful for understanding why. In addition, while the views of non-academic doctors have begun to be studied, the perspective and rationales of academic doctors remains under-researched. It seems important to investigate the views of those with a research-orientation, given the emphasis on the need for more scientific evidence in recent debates on CAM.</p> <p>Methods</p> <p>This exploratory study used qualitative methods to explore academic doctors' views of CAM and the rationales they provided for their views. A purposeful sampling strategy was used to identify doctors with a dual clinical and academic role in the Bristol area, with an anticipated variety of views on CAM. Semi-structured interviews were conducted with nine doctors. The data were analysed thematically, drawing on the Framework Approach.</p> <p>Results</p> <p>The doctors expressed a spectrum of views on CAM, falling into three broad groups: the 'enthusiasts', the 'sceptics' and the 'undecided'. Scepticism or uncertainty about the value of CAM was prominent, except among those practising a form of CAM. A variety of rationales underpinned their perspectives on CAM, a key recurring rationale being their perspective on the scientific evidence base. The main themes arising included: the role of doctors' professional experiences of conventional medicine and CAM in shaping their attitudes towards CAM, doctor-patient communication about CAM and patient disclosure, whether there is a need for training and education in CAM for doctors, a hierarchy of acceptability of CAM and the nature of evidence; and the role of CAM within the NHS.</p> <p>Conclusion</p> <p>Despite the caution or scepticism towards CAM expressed by doctors in this study, more open doctor-patient communication about CAM may enable doctors' potential concerns about CAM to be addressed, or at least enhance their knowledge of what treatments or therapies their patients are using. Offering CAM to patients may serve to enhance patients' treatment choices and even increase doctors' fulfilment in their practice. However, given the recurring concerns about lack of scientific evidence expressed by the doctors in this study, perceptions of the evidence base may remain a significant barrier to greater integration of CAM within the NHS.</p

    Molecular Structure and Dimeric Organization of the Notch Extracellular Domain as Revealed by Electron Microscopy

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    Background: The Notch receptor links cell fate decisions of one cell to that of the immediate cellular neighbor. In humans, malfunction of Notch signaling results in diseases and congenital disorders. Structural information is essential for gaining insight into the mechanism of the receptor as well as for potentially interfering with its function for therapeutic purposes. Methodology/Principal Findings: We used the Affinity Grid approach to prepare specimens of the Notch extracellular domain (NECD) of the Drosophila Notch and human Notch1 receptors suitable for analysis by electron microscopy and three-dimensional (3D) image reconstruction. The resulting 3D density maps reveal that the NECD structure is conserved across species. We show that the NECD forms a dimer and adopts different yet defined conformations, and we identify the membrane-proximal region of the receptor and its ligand-binding site. Conclusions/Significance: Our results provide direct and unambiguous evidence that the NECD forms a dimer. Our studies further show that the NECD adopts at least three distinct conformations that are likely related to different functional states of the receptor. These findings open the way to now correlate mutations in the NECD with its oligomeric state and conformation

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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