11,172 research outputs found

    Volunteer studies replacing animal experiments in brain research - Report and recommendations of a Volunteers in Research and Testing workshop

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    One Hundred Cases of Localized Laryngeal Amyloidosis - Evidence for Future Management

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    Objective/Hypothesis: To update the current understanding of localized laryngeal amyloidosis by analyzing the NHS National Amyloidosis Database and to further clarify the important ongoing management issues. Study Design: Retrospective review, case series. Methods: Patients with laryngeal amyloid were identified from the database of the NHS National Amyloidosis Center, UCL, Royal Free Hospital, London between 2000 and 2017. Patient demographics and disease profile were collated, including the exact location of amyloid deposit, treatments if any, and progression of disease. Results: One hundred and three patients with localized laryngeal amyloid where identified from the database, with a mean age of 54 at diagnosis and female to male ratio of 54:49. Three patients were excluded from further analysis due to limited database information. The majority of amyloid was found in either the supraglottis (44) or glottis (53) but all the laryngeal subsites were involved. One-third of the patients (34) had amyloid in more than one laryngeal subsite. No patients were found to progress to systemic amyloid, but many progressed locally to other subsites or further down the LTB tree (29%). Three patients were successfully treated with radiotherapy after other modalities had failed. Conclusions: This is the largest case series reported to date of localized laryngeal amyloidosis. It highlights the high incidence of multifocal disease and the significant proportion of patients who progressed, not to systemic amyloidosis but to more extensive localized amyloid. We recommend that in all cases of laryngeal amyloid, patients should undergo a thorough assessment of the upper and lower airways and have ongoing surveillance for at least 15 years

    Testing equality of variances in the analysis of repeated measurements

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    The problem of comparing the precisions of two instruments using repeated measurements can be cast as an extension of the Pitman-Morgan problem of testing equality of variances of a bivariate normal distribution. Hawkins (1981) decomposes the hypothesis of equal variances in this model into two subhypotheses for which simple tests exist. For the overall hypothesis he proposes to combine the tests of the subhypotheses using Fisher's method and empirically compares the component tests and their combination with the likelihood ratio test. In this paper an attempt is made to resolve some discrepancies and puzzling conclusions in Hawkins's study and to propose simple modifications.\ud \ud The new tests are compared to the tests discussed by Hawkins and to each other both in terms of the finite sample power (estimated by Monte Carlo simulation) and theoretically in terms of asymptotic relative efficiencies

    The Meinunger "Nicht Rote" Objects

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    Four high-latitude slow variable stars have been noted by Meinunger (1972) as "nicht rote" ("not red") objects and thus curious. We have previously reported (Margon & Deutsch 1997) that one of these objects, CC Boo, is in fact a QSO. Here we present observations demonstrating that the remaining three are also highly variable active galactic nuclei. The most interesting object of the four is perhaps S 10765 (= NGP9 F324-0276706), which proves to be a resolved galaxy at z=0.063. Despite the rapid and large reported variability amplitude (~1.6 mag), the spectrum is that of a perfectly normal galaxy, with no emission lines or evident nonthermal continuum. We also present new spectroscopic and photometric observations for AR CVn, suggested by Meinunger to be an RR Lyrae star despite its very faint magnitude (=19.4). The object is indeed one of the most distant RR Lyrae stars known, at a galactocentric distance of ~40 kpc.Comment: Accepted for publication in Publications of the Astronomical Society of the Pacific, Volume 111, January 1999; 14 pages including 4 figures and 1 tabl

    A Technique for the Nondestructive Detection of Voids and Composition Anomalies in Metal Matrix Composite Wires Using X or Îł Rays

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    An initial study of a technique proposed for the nondestructive testing of metal matrix composites is the subject of this paper. These composites are manufactured in the form of approximately 1/2-mm-diameter “precursor” wires. Larger structures are fabricated by diffusion bonding of lay-ups. Reliable nondestructive quality control indicators of wire integrity have not yet been developed although a number of possibilities are being examined.1 Testing of the precursor wires is difficult because current manufacturing processes produce wires that may be entirely satisfactory but that vary in cross-sectional geometry, in surface properties, and sometimes in the amount of matrix material that is present. Techniques based on observations of wire resistance, surface emissivity, and sound emission signatures are difficult to interpret because of these characteristics. Wire imaging using x-ray or neutron techniques is also difficult because large lengths of wire must be examined with a resolution in the plane of the wire exceeding 50 line pairs per millimeter

    System for the measurement of ultra-low stray light levels

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    An apparatus is described for measuring the effectiveness of stray light suppression light shields and baffle arrangements used in optical space experiments and large space telescopes. The light shield and baffle arrangement and a telescope model are contained in a vacuum chamber. A source of short, high-powered light energy illuminates portions of the light shield and baffle arrangement and reflects a portion of same to a photomultiplier tube by virtue of multipath scattering. The resulting signal is transferred to time-channel electronics timed by the firing of the high energy light source allowing time discrimination of the signal thereby enabling the light scattered and suppressed by the model to be distinguished from the walls and holders around the apparatus

    Broadcasting graphic war violence: the moral face of Channel 4

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    Drawing on empirical data from Channel 4 (C4) regarding the broadcasting of violent war imagery, and positioned within Goffman’s notion of the interaction ritual (1959, 1967), this article investigates how C4 negotiate potentially competing commercial, regulatory and moral requirements through processes of discretionary decision-making. Throughout, the article considers the extent to which these negotiations are presented through a series of ‘imaginings’ – of C4 and its audience – which serve to simultaneously guide and legitimate the decisions made. This manifestation of imaginings moves us beyond more blanket explanations of ‘branding’ and instead allows us to see the final programmes as the end product of a series of complex negotiations and interactions between C4 and those multiple external parties significant to the workings of their organization. The insights gleaned from this case study are important beyond the workings of C4 because they help elucidate how all institutions and organizations may view, organize and justify their practices (to both themselves and others) within the perceived constraints in which they operate

    Alterations in vasodilator-stimulated phosphoprotein (VASP) phosphorylation: associations with asthmatic phenotype, airway inflammation and ÎČ\u3csub\u3e2\u3c/sub\u3e-agonist use

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    Background Vasodilator-stimulated phosphoprotein (VASP) mediates focal adhesion, actin filament binding and polymerization in a variety of cells, thereby inhibiting cell movement. Phosphorylation of VASP via cAMP and cGMP dependent protein kinases releases this brake on cell motility. Thus, phosphorylation of VASP may be necessary for epithelial cell repair of damage from allergen-induced inflammation. Two hypotheses were examined: (1) injury from segmental allergen challenge increases VASP phosphorylation in airway epithelium in asthmatic but not nonasthmatic normal subjects, (2) regular in vivo ÎČ2-agonist use increases VASP phosphorylation in asthmatic epithelium, altering cell adhesion. Methods Bronchial epithelium was obtained from asthmatic and non-asthmatic normal subjects before and after segmental allergen challenge, and after regularly inhaled albuterol, in three separate protocols. VASP phosphorylation was examined in Western blots of epithelial samples. DNA was obtained for ÎČ2-adrenergic receptor haplotype determination. Results Although VASP phosphorylation increased, it was not significantly greater after allergen challenge in asthmatics or normals. However, VASP phosphorylation in epithelium of nonasthmatic normal subjects was double that observed in asthmatic subjects, both at baseline and after challenge. Regularly inhaled albuterol significantly increased VASP phosphorylation in asthmatic subjects in both unchallenged and antigen challenged lung segment epithelium. There was also a significant increase in epithelial cells in the bronchoalveolar lavage of the unchallenged lung segment after regular inhalation of albuterol but not of placebo. The haplotypes of the ÎČ2-adrenergic receptor did not appear to associate with increased or decreased phosphorylation of VASP. Conclusion Decreased VASP phosphorylation was observed in epithelial cells of asthmatics compared to nonasthmatic normals, despite response to ÎČ-agonist. The decreased phosphorylation does not appear to be associated with a particular ÎČ2-adrenergic receptor haplotype. The observed decrease in VASP phosphorylation suggests greater inhibition of actin reorganization which is necessary for altering attachment and migration required during epithelial repair

    The X-ray Properties of z>4 Quasars

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    We report on a search for X-ray emission from quasars with redshifts greater than four using the ROSAT public database. Our search has doubled the number of z>4 quasars detected in X-rays from 6 to 12. Most of those known prior to this work were radio-loud and X-ray selected sources; our study increases the number of X-ray detected, optically selected z>4 quasars from one to seven. We present their basic X-ray properties and compare these to those of lower redshift quasars. We do not find any evidence for strong broad-band spectral differences between optically selected z>4 quasars and those at lower redshifts.Comment: 7 pages, 4 figures included, LaTeX emulateapj.sty, accepted for publication in the Astronomical Journa
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