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11.
Paroxysmal vocal cord movement/motion (PVCM), paroxysmal vocal cord dysfunction (PVCD), episodic paroxysmal laryngospasm (EPL), and irritable larynx syndrome (ILS) are terms used to describe laryngeal dysfunction masquerading as asthma, upper airway obstruction, or functional and organic voice disorders. The differential diagnosis of PVCM, PVCD, EPL, and ILS is critical to successful medical and behavioral management of the patient. During the past 10 years, 27 subjects, ages 15–79 years, were identified to have paroxysms of inspiratory stridor, acute respiratory distress, associated aphonia and dysphonia, resulting in misdiagnosis and unnecessary emergency treatments, including endotracheal intubation, cardiopulmonary resuscitation, massive pharmacotherapy, or tracheostomy. A multifactorial management program is proposed utilizing principles of motor learning, neurolinguistic programming model, respiratory and phonatory synchronization, relaxation techniques, concurrent monitoring of behavioral adjustments, and formal psychological counseling. 相似文献
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Robert L. Barry Joy M. Williams L. Martyn Klassen Jason P. Gallivan Jody C. Culham Ravi S. Menon 《Magnetic resonance imaging》2010
Blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is currently the dominant technique for non-invasive investigation of brain functions. One of the challenges with BOLD fMRI, particularly at high fields, is compensation for the effects of spatiotemporally varying magnetic field inhomogeneities (ΔB0) caused by normal subject respiration and, in some studies, movement of the subject during the scan to perform tasks related to the functional paradigm. The presence of ΔB0 during data acquisition distorts reconstructed images and introduces extraneous fluctuations in the fMRI time series that decrease the BOLD contrast-to-noise ratio. Optimization of the fMRI data-processing pipeline to compensate for geometric distortions is of paramount importance to ensure high quality of fMRI data. To investigate ΔB0 caused by subject movement, echo-planar imaging scans were collected with and without concurrent motion of a phantom arm. The phantom arm was constructed and moved by the experimenter to emulate forearm motions while subjects remained still and observed a visual stimulation paradigm. These data were then subjected to eight different combinations of preprocessing steps. The best preprocessing pipeline included navigator correction, a complex phase regressor and spatial smoothing. The synergy between navigator correction and phase regression reduced geometric distortions better than either step in isolation and preconditioned the data to make them more amenable to the benefits of spatial smoothing. The combination of these steps provided a 10% increase in t-statistics compared to only navigator correction and spatial smoothing and reduced the noise and false activations in regions where no legitimate effects would occur. 相似文献
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[formula: see text] Ab initio calculations reveal a significant binding interaction between water and hexafluorobenzene in a geometry that points the oxygen lone pairs directly into the face of the pi system. The geometry is as anticipated from electrostatic arguments emphasizing the substantial quadrupole moment of the aromatic. A second, off-axis geometry is also found which is also consistent with a substantial electrostatic interaction. 相似文献
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Given a single-input single-output system {A,b,c} with strictly proper transfer function g(s), we derive a Lanczos-based method to construct a tridiagonal state-space model
approximating the “pre-filtered” transfer function f(s)g(s), where f(s) is given in factored form
. We also show how to apply this idea to the Arnoldi process and mention a few other extensions.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Wind instrumentalists, especially brass players, and singers share common factors, including vocal tract shape, function and pressure, vocal fold opening and closure, breath vector of force and air flow rates. To understand the mechanism and function of the vocal folds with a pathological lesion, it is necessary to visualize the differing interactions of the vocal tract during wind and brass instrument playing and in singing. A school band director, singer, wind and brass instrumentalist, was referred by musician colleagues with intermittent dysphonia, aphonia, and inability to sing high notes. Simultaneous videolaryngoscopy, with and without stroboscopy, and external video examination were documented. An hourglass glottis with a sessile, cystic polyp of the left vocal fold were recorded and studied during phonation and the playing of 3 instruments. The techniques of glottic opening, closure, configuration and function varied with the type of instrument and phonatory function. Singing was adversely affected by the vocal fold polyp but no harmful interaction occurred during wind/brass instrument playing. Down-stream loading in singers is at the laryngeal level and in wind/brass instrumentalists is at the embouchure. Preoperative voice therapy, phonomicrosurgery, and postoperative voice rest followed by voice therapy, succeeded in restoring her combined wind/brass instrumental and singing career. 相似文献
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Various problems are considered in an attempt to generalize the simplex algorithm of linear programming to a much wider class of convex bodies than the class of convex polytopes. A conjecture of D.G. Larman and C.A. Rogers is disproved by constructing a three-dimensional convex body K with an extreme point e, so that for a certain linear functional f, there are no paths in the one-skeleton of K leading from e, along which f strictly increases. Their conjectured generalization is, however, proved for the large class of three-dimensional convex bodies, all of whose extreme points are exposed.A strong generalization of the simplex algorithm is obtained for the class of all finite-dimensional convex bodies, where, for a given exposed point e of a convex body K, it is possible to find f-strictly-increasing paths in the one-skeleton of K, leading from e, for almost all linear functionals f.Research sponsored by the British Science Research Council. 相似文献
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W. Beusch M. Borghini S. Lauper D. Websdale L. Fluri F.X. Gentit P. Astbury J. Gallivan J. Jafar M. Letheren V. Steiner J.A. Wilson P. Le Du O. Guisan 《Nuclear Physics B》1975,99(1):53-60
The π?p→K0λ polarization has been measured at 5 GeV/c in the range 0<?t<1.4 (GeV/c)2. The polarization is small for ?t?0.4 (GeV/c)2, becoming negative at the higher values of ?t. 相似文献