385 research outputs found

    Diagnosis and treatment of carotid body paraganglioma: 21 years of experience at a clinical center of Serbia

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    BACKGROUND: The carotid body paraganglioma (chemodectoma) is a relatively rare neoplasm of obscure origin. These are usually benign and commonly present as asymptomatic cervical mass. PATIENTS AND METHODS: Records of 12 patients (9 female and 3 male) with carotid body tumors treated between 1982 and 2003, treated at our center were retrospectively reviewed. Data on classification, clinical presentation, and surgical treatment were extracted from the case records. Surgical complications and treatment outcome were noted and survival was calculated by actuarial method. The literature on carotid body paraganglioma was reviewed. RESULTS: The average age of the patients was 52 years (range 30–78 years). Eight of these cases presented as a large asymptomatic non-tender neck mass, and two each presented with dysphagia, and hoarseness of voice. As per Shamblin classification seven of tumors were type II and 5 were types III. In 7 cases subadventitial tumor excision was performed, while in 5 associated resection of both external and internal carotid arteries was carried out. The artery was repaired by end-to-end anastomosis in one case, with Dacron graft in one case, and with saphenous vein graft in 3 cases. There was no operative mortality. After a mean follow-up of 6.2 years (range 6 months to 20 years), there were no signs of tumor recurrence in any of the cases. CONCLUSIONS: Surgical excision is the treatment of choice for carotid body paragangliomas although radiation therapy is an option for patients who are not ideal candidates for surgery. For the tumors that are in intimate contact with carotid arteries, the treatment by vascular surgeon is recommended

    Parametrised Preisach Modelling of Hysteresis in High Temperature Superconductors

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    We present a parametrised Preisach-type model that describes the hysteresis exhibited by the high temperature superconductors (HTSC); hysteresis is the main cause for losses in the subcritical domain. The parametrised model, in combination with electrical measurements, is independent of geometry, number of filaments and other physical measures, and is identified by a novel method that uses electrical lock-in (loss) measurement technique, which greatly enhances the signal to noise ratio. Identification results from measurements on Bi-2223 multi-filamentary tapes are presented. We have further derived exact models for the hysteretic losses in strip and elliptic geometry strips, where the energy losses were calculated by Norris. The paper contains analysis of the Preisach Model, of its losses and of the suggested parametrisation

    Inpatient versus outpatient intravenous diuresis for the acute exacerbation of chronic heart failure

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    BACKGROUND: We established an IV outpatient diuresis (IVOiD) clinic and conducted a quality improvement project to evaluate safety, effectiveness and costs associated with outpatient versus inpatient diuresis for patients presenting with acute decompensated heart failure (ADHF) to the emergency department (ED). METHODS: Patients who were clinically diagnosed with ADHF in the ED, but did not have high-risk features, were either diuresed in the hospital or in the outpatient IVOiD clinic. The dose of IV diuretic was based on their home maintenance diuretic dose. The outcomes measured were the effects of diuresis (urine output, weight, hemodynamic and laboratory abnormalities), 30-90 day readmissions, 30-90 day death and costs. RESULTS: In total, 36 patients (22 inpatients and 14 outpatients) were studied. There were no significant differences in the baseline demographics between groups. The average inpatient stay was six days and the average IVOiD clinic days were 1.2. There was no significant difference in diuresis per day of treatment (1159 vs. 944 ml, p = 0.46). There was no significant difference in adverse outcomes, 30-90 day readmissions or 30-90 day deaths. There was a significantly lower cost in the IVOiD group compared to the inpatient group (839.4vs.839.4 vs. 9895.7, p=\u3c0.001). CONCLUSIONS: Outpatient IVOiD clinic diuresis may be a viable alternative to accepted clinical practice of inpatient diuresis for ADHF. Further studies are needed to validate this in a larger cohort and in different sites

    Core competencies for pain management: results of an interprofessional consensus summit.

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    ObjectiveThe objective of this project was to develop core competencies in pain assessment and management for prelicensure health professional education. Such core pain competencies common to all prelicensure health professionals have not been previously reported.MethodsAn interprofessional executive committee led a consensus-building process to develop the core competencies. An in-depth literature review was conducted followed by engagement of an interprofessional Competency Advisory Committee to critique competencies through an iterative process. A 2-day summit was held so that consensus could be reached.ResultsThe consensus-derived competencies were categorized within four domains: multidimensional nature of pain, pain assessment and measurement, management of pain, and context of pain management. These domains address the fundamental concepts and complexity of pain; how pain is observed and assessed; collaborative approaches to treatment options; and application of competencies across the life span in the context of various settings, populations, and care team models. A set of values and guiding principles are embedded within each domain.ConclusionsThese competencies can serve as a foundation for developing, defining, and revising curricula and as a resource for the creation of learning activities across health professions designed to advance care that effectively responds to pain

    Shot noise suppression at room temperature in atomic-scale Au junctions

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    Shot noise encodes additional information not directly inferable from simple electronic transport measurements. Previous measurements in atomic-scale metal junctions at cryogenic temperatures have shown suppression of the shot noise at particular conductance values. This suppression demonstrates that transport in these structures proceeds via discrete quantum channels. Using a high frequency technique, we simultaneously acquire noise data and conductance histograms in Au junctions at room temperature and ambient conditions. We observe noise suppression at up to three conductance quanta, with possible indications of current-induced local heating and 1/f1/f noise in the contact region at high biases. These measurements demonstrate the quantum character of transport at room temperature at the atomic scale. This technique provides an additional tool for studying dissipation and correlations in nanodevices.Comment: 15 pages, 4 figures + supporting information (6 pages, 6 figures

    A Variational Procedure for Time-Dependent Processes

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    A simple variational Lagrangian is proposed for the time development of an arbitrary density matrix, employing the "factorization" of the density. Only the "kinetic energy" appears in the Lagrangian. The formalism applies to pure and mixed state cases, the Navier-Stokes equations of hydrodynamics, transport theory, etc. It recaptures the Least Dissipation Function condition of Rayleigh-Onsager {\bf and in practical applications is flexible}. The variational proposal is tested on a two level system interacting that is subject, in one instance, to an interaction with a single oscillator and, in another, that evolves in a dissipative mode.Comment: 25 pages, 4 figure

    The number of transmission channels through a single-molecule junction

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    We calculate transmission eigenvalue distributions for Pt-benzene-Pt and Pt-butadiene-Pt junctions using realistic state-of-the-art many-body techniques. An effective field theory of interacting π\pi-electrons is used to include screening and van der Waals interactions with the metal electrodes. We find that the number of dominant transmission channels in a molecular junction is equal to the degeneracy of the molecular orbital closest to the metal Fermi level.Comment: 9 pages, 8 figure
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