14,416 research outputs found

    Phase II study of tight glycaemic control in COPD patients with exacerbations admitted to the acute medical unit.

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    BACKGROUND: Hyperglycaemia is associated with poor outcomes from exacerbations of chronic obstructive pulmonary disease (COPD). Glycaemic control could improve outcomes by reducing infection, inflammation and myopathy. Most patients with COPD are managed on the acute medical unit (AMU) outside intensive care (ICU). OBJECTIVE: To determine the feasibility, safety and efficacy of tight glycaemic control in patients on an AMU. DESIGN: Prospective, non-randomised, phase II, single-arm study of tight glycaemic control in COPD patients with acute exacerbations and hyperglycaemia admitted to the AMU. Participants received intravenous, then subcutaneous, insulin to control blood glucose to 4.4-6.5 mmol/l. Tight glycaemic control was evaluated: feasibility, protocol adherence; acceptability, patient questionnaire; safety, frequency of hypoglycaemia (capillary blood glucose (CBG) <2.2 mmol/l and 2.2-3.3 mmol/l); efficacy, median CBG, fasting CBG, proportion of measurements/time in target range, glycaemic variability. RESULTS: were compared with 25 published ICU studies. Results 20 patients (10 females, age 71 ± 9 years; forced expiratory volume in 1 s: 41 ± 16% predicted) were recruited. Tight glycaemic control was feasible (78% CBG measurements and 89% of insulin-dose adjustments were adherent to protocol) and acceptable to patients. 0.2% CBG measurements were <2.2 mmol/l and 4.1% measurements 2.2-3.3 mmol/l. The study CBG and proportion of measurements/time in target range were similar to that of ICU studies, whereas the fasting CBG was lower, and the glycaemic variability was greater. CONCLUSIONS: Tight glycaemic control is feasible and has similar safety and efficacy on AMU to ICU. However, as more recent ICU studies have shown no benefit and possible harm from tight glycaemic control, alternative strategies for blood glucose control in COPD exacerbations should now be explored. Trial registration number ISRCTN: 42412334. http://Clinical.Trials.gov NCT00764556

    Expression of human adenosine deaminase in nonhuman primates after retrovirus-mediated gene transfer.

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    Primate bone marrow cells were infected with a retroviral vector carrying the genes for human adenosine deaminase (h-ADA) and bacterial neomycin resistance (neor). The infected cells were infused back into the lethally irradiated donor animals. Several monkeys fully reconstituted and were shown to express the h-ADA and neor genes at low levels in their recirculating hematopoietic cells for short periods of time

    Kinematic dynamo action in a sphere: Effects of periodic time-dependent flows on solutions with axial dipole symmetry

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    Choosing a simple class of flows, with characteristics that may be present in the Earth's core, we study the ability to generate a magnetic field when the flow is permitted to oscillate periodically in time. The flow characteristics are parameterised by D, representing a differential rotation, M, a meridional circulation, and C, a component characterising convective rolls. Dynamo action is sensitive to these flow parameters and fails spectacularly for much of the parameter space where magnetic flux is concentrated into small regions. Oscillations of the flow are introduced by varying the flow parameters in time, defining a closed orbit in the space (D,M). Time-dependence appears to smooth out flux concentrations, often enhancing dynamo action. Dynamo action can be impaired, however, when flux concentrations of opposite signs occur close together as smoothing destroys the flux by cancellation. It is possible to produce geomagnetic-type reversals by making the orbit stray into a region where the steady flows generate oscillatory fields. In this case, however, dynamo action was not found to be enhanced by the time-dependence. A novel approach is taken to solving the time-dependent eigenvalue problem, where by combining Floquet theory with a matrix-free Krylov-subspace method we avoid large memory requirements for storing the matrix required by the standard approach.Comment: 22 pages, 12 figures. Geophys. Astrophys. Fluid Dynam., as accepted (2004

    High-resolution spectroscopy of the R Coronae Borealis and Other Hydrogen Deficient Stars

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    High-resolution spectroscopy is a very important tool for studying stellar physics, perhaps, particularly so for such enigmatic objects like the R Coronae Borealis and related Hydrogen deficient stars that produce carbon dust in addition to their peculiar abundances. Examples of how high-resolution spectroscopy is used in the study of these stars to address the two major puzzles are presented: (i) How are such rare H-deficient stars created? and (ii) How and where are the obscuring soot clouds produced around the R Coronae Borealis stars?Comment: 16 pages, 9 figures, Astrophysics and Space Science Proceedings, Springer-Verlag, Berlin, 201

    Topics in Quantum Computers

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    I provide an introduction to quantum computers, describing how they might be realized using language accessible to a solid state physicist. A listing of the minimal requirements for creating a quantum computer is given. I also discuss several recent developments in the area of quantum error correction, a subject of importance not only to quantum computation, but also to some aspects of the foundations of quantum theory.Comment: 22 pages, Latex, 1 eps figure, Paper to be published in "Mesoscopic Electron Transport", edited by L. Kowenhoven, G. Schoen and L. Sohn, NATO ASI Series E, Kluwer Ac. Publ., Dordrecht. v2: typos in refrences fixe

    Photon statistics of a random laser

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    A general relationship is presented between the statistics of thermal radiation from a random medium and its scattering matrix S. Familiar results for black-body radiation are recovered in the limit S to 0. The mean photocount is proportional to the trace of 1-SS^dagger, in accordance with Kirchhoff's law relating emissivity and absorptivity. Higher moments of the photocount distribution are related to traces of powers of 1-SS^dagger, a generalization of Kirchhoff's law. The theory can be applied to a random amplifying medium (or "random laser") below the laser threshold, by evaluating the Bose-Einstein function at a negative temperature. Anomalously large fluctuations are predicted in the photocount upon approaching the laser threshold, as a consequence of overlapping cavity modes with a broad distribution of spectral widths.Comment: 26 pages, including 9 figure

    The melanoma-specific graded prognostic assessment does not adequately discriminate prognosis in a modern population with brain metastases from malignant melanoma

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    The melanoma-specific graded prognostic assessment (msGPA) assigns patients with brain metastases from malignant melanoma to 1 of 4 prognostic groups. It was largely derived using clinical data from patients treated in the era that preceded the development of newer therapies such as BRAF, MEK and immune checkpoint inhibitors. Therefore, its current relevance to patients diagnosed with brain metastases from malignant melanoma is unclear. This study is an external validation of the msGPA in two temporally distinct British populations.Performance of the msGPA was assessed in Cohort I (1997-2008, n=231) and Cohort II (2008-2013, n=162) using Kaplan-Meier methods and Harrell's c-index of concordance. Cox regression was used to explore additional factors that may have prognostic relevance.The msGPA does not perform well as a prognostic score outside of the derivation cohort, with suboptimal statistical calibration and discrimination, particularly in those patients with an intermediate prognosis. Extra-cerebral metastases, leptomeningeal disease, age and potential use of novel targeted agents after brain metastases are diagnosed, should be incorporated into future prognostic models.An improved prognostic score is required to underpin high-quality randomised controlled trials in an area with a wide disparity in clinical care
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