978 resultados para PROTON-CONDUCTING MEMBRANES


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Background A European screening tool (STOPP/START) has been formulated to identify the prescribing of potentially inappropriate medicines (PIMs) and potential prescribing omissions (PPOs). Pharmacists working in community pharmacies could use STOPP/START as a guide to conducting medication use reviews; however, community pharmacists do not routinely have access to patients' clinical records. Objective To compare the PIM and PPO detection rates from application of the STOPP/START criteria to patients' medication details alone with the detection rates from application of STOPP/START to information on patients' medications combined with clinical information. Setting Community Pharmacy. Method Three pharmacists applied STOPP/START to 250 patient medication lists, containing information regarding dose, frequency and duration of treatment. The PIMs and PPOs identified by each pharmacist were compared with those identified by consensus agreement of two other pharmacists, who applied STOPP/START criteria using patients' full clinical records. Main outcome measure The main outcome measures were: (1) PIM and PPO detection rates among pharmacists with access to patients' clinical information compared to PIM and PPO detection rates among pharmacists using patients' medication information only, and (2) the levels of agreement (calculated using Cohen's kappa statistic (k)) for the three most commonly identified PIMs and PPOs. Results Pharmacists with access to patients' clinical records identified significantly fewer PIMs than pharmacists without (p = 0.002). The three most commonly identified PIMs were benzodiazepines, proton pump inhibitors and duplicate drug classes, with kappa (k) statistic agreement ranges of 0.87-0.97, 0.60-0.68 and 0.39-0.85 respectively. PPOs were identified more often (p 

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The permeability of the outer membrane (OM) to hydrophobic probes and its susceptibility to bactericidal cationic peptides were investigated for natural rough Brucella ovis and for mutant rough Brucella abortus strains. The OM of B. ovis displayed an abrupt and faster kinetic profile than rough B. abortus during the uptake of the hydrophobic probe N-phenyl-naphthylamine. B. ovis was more sensitive than rough B. abortus to the action of cationic peptides. Bactenecins 5 and 7 induced morphological alterations on the OMs of both rough Brucella strains. B. ovis lipopolysaccharide (LPS) captured considerably more polymyxin B than LPSs from both rough and smooth B. abortus strains. Polymyxin B, poly-L-lysine, and poly-L-ornithine produced a thick coating on the surfaces of both strains, which was more evident in B. ovis than in rough B. abortus. The distinct functional properties of the OMs of these two rough strains correlate with some structural differences of their OMs and with their different biological behaviors in animals and culture cells.

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Background. Interdisciplinary research has been promoted as an optimal research paradigm in the health sciences, yet little is known about how researchers experience interdisciplinarity in practice. This study sought to determine how interdisciplinary research was conceptualized and operationalized from the researcher's perspective and to better understand how best to facilitate interdisciplinary research success. Methods. Key informant interviews were conducted with health researchers with expertise or experience in conducting interdisciplinary research. Interviews were completed either in person or over the telephone using a semi-structured interview guide. Data collection occurred simultaneously with data analysis so that emerging themes could be explored in subsequent interviews. A content analysis approach was used. Results. Nineteen researchers took part in this study. Interdisciplinary research was conceptualized disparately between participants, and there was modest attention towards operationalization of interdisciplinary research. There was one overriding theme, "It's all about relationships", that emerged from the data. Within this theme, there were four related subthemes: 1) Involvement in interdisciplinary research; 2) Why do I do interdisciplinary research?; 3) Managing and fostering interdisciplinary relationships; and 4) The prickly side to interdisciplinary research. Together, these themes suggest that the choice to conduct interdisciplinary research, though often driven by the research question, is highly influenced by interpersonal and relationship-related factors. In addition, researchers preferred to engage in interdisciplinary research with those that they had already established relationships and where their role in the research process was clearly articulated. A focus on relationship building was seen as a strong facilitator of interdisciplinary success. Conclusion. Many health researchers experienced mixed reactions towards their involvement in interdisciplinary research. A well thought-out rationale for interdisciplinary research, and strategies to utilize the contribution of each researcher involved were seen as facilitators towards maximizing the benefits that could be derived from interdisciplinary research. © 2008 Nair et al; licensee BioMed Central Ltd.

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Background/aims - Epiretinal and retrolental proliferation may occur during prolonged use of the novel tamponade agent perfluorohexyloctane (F H ). This study aims to determine whether there is any histological evidence that F H has a role in the formation of these membranes. Methods - Eight epiretinal membranes and three opaque posterior lens capsules were excised from patients in whom F H had been used as a long term retinal tamponade agent. The membranes and capsules were examined employing light microscopic methods, including immunohistochemistry. Results - The epiretinal membranes showed histological features typical of proliferative vitreoretinopathy (PVR) epiretinal membranes, but they also exhibited a dense macrophagic infiltration. In addition, three of the membranes contained multinucleated cells. Macrophages represented up to 30% of the cells present and appeared to contain large intracytoplasmic vacuoles. Similar cells were seen on the back of the posterior lens capsule in one specimen and all three capsules had posterior migration of lens epithelium. Conclusion - The pathological findings are not simply those of PVR. The macrophage infiltration suggests that there may be a biological reaction to F H which could reflect its surmised propensity to emulsify. Further investigations concerning the cellular response to this promising tamponade agent are warranted.

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Density-functional theory (DFT) is used to examine the basal and prism surfaces of ice Ih. Similar surface energies are obtained for the two surfaces; however, in each case a strong dependence of the surface energy on surface proton order is identified. This dependence, which can be as much as 50% of the absolute surface energy, is significantly larger than the bulk dependence (< 1%) on proton order, suggesting that the thermodynamic ground state of the ice surface will remain proton ordered well above the bulk order-disorder temperature of about 72 K. On the basal surface this suggestion is supported by Monte Carlo simulations with an empirical potential and solution of a 2D Ising model with nearest neighbor interactions taken from DFT. Order parameters that define the surface energy of each surface in terms of nearest neighbor interactions between dangling OH bonds (those which point out of the surface into vacuum) have been identified and are discussed. Overall, these results suggest that proton order-disorder effects have a profound impact on the stability of ice surfaces and will most likely have an effect on ice surface reactivity as well as ice crystal growth and morphology. S Supplementary data are available from stacks.iop.org/JPhysCM/22/074209/mmedia

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Ice Ih is comprised of orientationally disordered water molecules giving rise to positional disorder of the hydrogen atoms in the hydrogen bonded network of the lattice. Here we arrive at a first principles determination of the surface energy of ice Ih and suggest that the surface of ice is significantly more proton ordered than the bulk. We predict that the proton order-disorder transition, which occurs in the bulk at similar to 72 K, will not occur at the surface at any temperature below surface melting. An order parameter which defines the surface energy of ice Ih surfaces is also identified.

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Results from first-principles calculations on the subtle energetics of proton ordering in ice phases are shown only to depend on the electrostatic components of the total energy. Proton ordered ice phases can therefore be predicted using electronic structure methods or a tailored potential model. However, analysis of the electron density reveals that high order multipole components, up to hexadecapole, are needed to adequately capture total energy differences between proton ordered and disordered phases. This suggests that current potential models may be unable to reproduce the position of proton ordered ice phases in the phase diagram without extensions to describe high order electrostatics. (c) 2006 Elsevier B.V. All rights reserved.

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Biological validation of new radiotherapy modalities is essential to understand their therapeutic potential. Antiprotons have been proposed for cancer therapy due to enhanced dose deposition provided by antiproton-nucleon annihilation. We assessed cellular DNA damage and relative biological effectiveness (RBE) of a clinically relevant antiproton beam. Despite a modest LET (,19 keV/mm), antiproton spread out Bragg peak (SOBP) irradiation caused significant residual c-H2AX foci compared to X-ray, proton and antiproton plateau irradiation. RBE of ,1.48 in the SOBP and ,1 in the plateau were measured and used for a qualitative effective dose curve comparison with proton and carbon-ions. Foci in the antiproton SOBP were larger and more structured compared to X-rays, protons and carbon-ions. This is likely due to overlapping particle tracks near the annihilation vertex, creating spatially correlated DNA lesions. No biological effects were observed at 28–42 mm away from the primary beam suggesting minimal risk from long-range secondary particles.

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This investigation was designed to determine whether low dose radiation to the macular region could influence the natural course of age-related subfoveal neovascularisation. Nineteen patients with subfoveal membranes due to age-related macular degeneration (ARMD) were treated with 10 or 15 Gy of 6 MV photons and seven patients who declined treatment were followed up as controls. Six controls and all treated patients had completed follow up times of at least 12 months. Visual acuity was maintained or improved in 78% and 63% of treated patients at their 6 and 12 month follow up examinations respectively. By contrast visual acuity showed steady deterioration in six of seven controls. Significant neovascular membrane regression, as measured by image analysis, was recorded in 68% and 77% of treated patients at 6 and 12 months post-radiation, whereas the membranes in all seven control patients showed progressive enlargement. This study suggests that low doses of radiation can maintain central vision and induce regression of subfoveal neovascular membranes of ARMD in a significant proportion of patients. We now believe it appropriate to proceed to a prospective randomised study to test this hypothesis further.

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Clinical psychologists often use qualitative methods to explore sensitive topics with vulnerable individuals, yet there has been little discussion of the specific ethical issues involved. For clinicians conducting qualitative research, there are likely to be ethical dilemmas associated with being both a researcher and a practitioner. We argue that this overarching issue frames all other ethical issues raised. This article provides an overview of the range of ethical issues that have been discussed in general in relation to qualitative research and considers the specific nature of these in relation to the discipline of clinical psychology. Such issues will be exemplified by reference to some of our own research and practice and the extant literature. We conclude with some suggestions for good practice, although our aim is to trigger debate rather than to establish prescriptive guidelines.

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Tissue microarrays (TMAs) represent a powerful method for undertaking large-scale tissue-based biomarker studies. While TMAs offer several advantages, there are a number of issues specific to their use which need to be considered when employing this method. Given the investment in TMA-based research, guidance on design and execution of experiments will be of benefit and should help researchers new to TMA-based studies to avoid known pitfalls. Furthermore, a consensus on quality standards for TMA-based experiments should improve the robustness and reproducibility of studies, thereby increasing the likelihood of identifying clinically useful biomarkers. In order to address these issues, the National Cancer Research Institute Biomarker and Imaging Clinical Studies Group organized a 1-day TMA workshop held in Nottingham in May 2012. The document herein summarizes the conclusions from the workshop. It includes guidance and considerations on all aspects of TMA-based research, including the pre-analytical stages of experimental design, the analytical stages of data acquisition, and the postanalytical stages of data analysis. A checklist is presented which can be used both for planning a TMA experiment and interpreting the results of such an experiment. For studies of cancer biomarkers, this checklist could be used as a supplement to the REMARK guidelines.