The Relationship Between Chronic Cough and Paradoxical Vocal Fold Movement: A Review of the Literature

SUMMARY: Chronic cough (CC) and paradoxical vocal fold movement (PVFM) are debilitating conditions. PVFM has been given many labels, including vocal cord dysfunction, Munchausen's stridor, functional inspiratory stridor, nonorganic functional or psychogenic upper airway obstruction, factitious asthma, psychogenic stridor, emotional laryngeal wheezing, and episodic laryngeal dyskinesia. Although CC and PVFM have been considered separate entities in many reports, there is preliminary support for the notion that there may be an underlying link between these two conditions. Speech pathologists have become increasingly involved in the treatment of these patients and therefore need to understand the theoretical background of these disorders, the pathophysiological links between the two, and the impact of voice disorders on these populations. The aim of this article is to review the current literature on CC and PVFM from a speech pathology perspective to provide a model for defining and conceptualizing the disorders and to provide a framework for management and future research.     

Relaxation schemes for the shallow water equations

We present a class of first and second order in space and time relaxation schemes for the shallow water (SW) equations. A new approach of incorporating the geometrical source term in the relaxation model is also presented. The schemes are based on classical relaxation models combined with Runge–Kutta time stepping mechanisms. Numerical results are presented for several benchmark test problems with or without the source term present. Copyright © 2003 John Wiley & Sons, Ltd.     

Solitons in fibers with polarization mode dispersion

Evaluating the relative time displacement of the two orthogonally polarized components of a pulse propagating down a birefringent optical fiber is considered. A method that provides analytical expressions for this time displacement is described and generalizes analytical results already published.     

Programmable terahertz metamaterials through V-beam electrothermal devices

We report on the application of various optimization methods as a very promising simulation approach for the design of true integrated optical devices by means of inverse design. We show that these techniques provide a global optimum toward one or various functional objectives at a reasonable computational cost. The results obtained by these methods are far better than intuitive design procedures and clearly outperform trial-and-error based models. We illustrate their performance by using a series of inverse-designed practical photonic devices.     

Optimized NMR Experiments for the Isolation of I=1/2 Manifold Transitions in Methyl Groups of Proteins

Optimized NMR experiments are developed for isolating magnetization belonging to the I=1/2 manifolds of ¹³CH₃ methyl groups in proteins, enabling the manipulation of the magnetization of a ¹³CH₃ moiety as if it were an AX (¹H-¹³C) spin-system. These experiments result in the same ‘simplification’ of a ¹³CH₃ spin-system that would be obtained from the production of {¹³CHD₂}-methyl-labeled protein samples. The sensitivity of I=1/2 manifold-selection experiments is a factor of approximately 2 less than that of the corresponding experiments acquired on {¹³CHD₂}-labeled methyl groups. The methodology described here is primarily intended for small-to-medium sized proteins, where the losses in sensitivity associated with the isolation of I=1/2 manifold transitions can be tolerated. Several NMR applications that benefit from simplification of the ¹³CH₃ (AX₃) spin-systems are described, with an emphasis on the measurements of methyl ¹H-¹³C residual dipolar couplings in a {¹³CH₃}-methyl-labeled deletion mutant of the human chaperone DNAJB6b, where modulation of NMR signal intensities due to evolution of methyl ¹H-¹³C scalar and dipolar couplings follows a simple cosine function characteristic of an AX (¹H-¹³C) spin-system, significantly simplifying data analysis.     

Modulation by Phosphonium Ions of the Activity of Mitotropic Agents Based on the Chemiluminescence of Luminols

Mitochondria-targeting drugs and diagnostics are used in the monitoring and treatment of mitochondrial pathologies. In this respect, a great number of functional compounds have been made mitotropic by covalently attaching the active moiety onto a triphenylphosphonium (TPP) cation. Among these compounds, a number of molecular detectors for reactive oxygen species (ROS) are based on fluorescent and chemiluminescent probes. In this regard, luminol (probably the most widely known chemiluminescent molecule) has been employed for a number of biological applications, including ROS detection. Its oxidation under specific conditions triggers a cascade of reactions, ultimately leading to the excited 3-aminophthalate (3AP *), which emits light upon deactivation. Hence, the photophysical interaction between the light-emitting species 3AP * and TPP cations needs to be evaluated, as it can add valuable information on the design of novel emission-based mitotropic systems. We herein investigate the quenching effect of ethyltriphenylphosphonium cation onto substituted 3-aminophthalates. These were prepared in situ upon hydrolysis of the corresponding anhydrides, which were synthesized from 3-aminophthalimides. Steady-state fluorescence and time-resolved experiments were employed for the evaluation of a possible electron transfer quenching by phosphonium ions. Our experimental results confirmed such quenching, suggesting it is mainly dynamic in nature. A minor contribution of static quenching that was also detected is attributed to complex formation in the ground state. Accordingly, the chemiluminescence of luminol was indeed strongly reduced in the presence of phosphonium ions. Our results have to be taken into account during the design of new chemiluminescent mitotropic drugs or diagnostic agents of the luminol family.     

A Characterization for Geodsic Spheres in Space Forms

We use the maximum principle for second-order elliptic operators to establish a sufficient condition for a compact hypersurface in a space form to be a geodesic sphere in terms of a pinching for the s-mean curvature.