A long-range quantum communication network is among the most promising applications of emerging quantum technologies. We discuss the potential of such a quantum internet for the secure transmission of classical and quantum information, as well as theoretical and experimental approaches and recent advances to realize them. We illustrate the involved concepts such as error correction, teleportation or quantum repeaters and consider an approach to this topic based on catchy visualizations as a context-based, modern treatment of quantum theory at high school.
Vocal folds are an essential part of human voice production. The biomechanical properties are a good indicator for pathological changes. In particular, as an oscillation system, changes in the biomechanical properties have an impact on the vibration behavior. Subsequently, those changes could lead to voice-related disturbances. However, no existing examination combines biomechanical properties and spatial imaging. Therefore, we propose an image registration-based approach, using ultrasound in order to gain this information synchronously. We used a quasi-static load to compress the tissue and measured the displacement by image registration. The strain distribution was directly calculated from the displacement field, whereas the elastic properties were estimated by a finite element model. In order to show the feasibility and reliability of the algorithm, we tested it on gelatin phantoms. Further, by examining ex vivo porcine vocal folds, we were able to show the practicability of the approach. We displayed the strain distribution in the tissue and the elastic properties of the vocal folds. The results were superimposed on the corresponding ultrasound images. The findings are promising and show the feasibility of the suggested approach. Possible applications are in improved diagnosis of voice disorders, by measuring the biomechanical properties of the vocal folds with ultrasound. The transducer will be placed on the vocal folds of the anesthetized patient, and the elastic properties will be measured. Further, the understanding of the vocal folds’ biomechanics and the voice forming process could benefit from it.
The diagnosis of changes in the structure of the vocal folds is an important clinical task. There is no approach available, which is capable of getting synchronous spatial and biomechanical properties of them. Whereas biomechanical changes, particularly the elasticity, are a good maker for malignant and benign conditions. To gain the elastic characteristics of the vocal folds we are proposing an endoscopic approach using ultrasound elastography.
A measurement setup combined with a numerical simulation by a linear finite element analysis is presented as a method to determine the elastic modulus of both artificial and real tissue as a function of frequency. At the end, the future goal is to develop and validate the method to measure the elastic modulus of in-vivo human vocal folds over the human phonation frequency range. In the present study, a miniaturized acoustic pressure pipette aspiration technique is developed to measure the material characteristics of an isotropic silicone specimen with similar characteristics as human vocal folds. In previous studies, friction and compression force effects of the pipette tip wall on the surface of the sample and the radius of the pipette were not investigated. Moreover, the large scale of the measurement setups made them impossible to use for clinical applications. Therefore, two different pipette sample cross-section boundary conditions and two different pipette radii were used. With the aim of ensuring reliable results, we tested our method with pipettes of two different radii on four silicone samples with different consistencies over a frequency range of 50–500 Hz. The simulation verified the measurement results in which the strong dependency of the elastic modulus on the excitation frequency, radius of the pipette, the pipette tip compression force and friction was revealed. By the simulation results, two different frequency dependent equations were developed for calculating elastic modulus of the silicone mixtures in the two cross-section boundary conditions. It was concluded that using a very small gap in between the pipette tip and the specimen can cancel the impact of the pipette tip force and friction which are the major cause of uncertainty. However, if a connection between the pipette and the surface is unpreventable, the contact force should be restricted to be absolutely zero.
This paper presents a measurement setup which is able to measure the distribution of small scale pressure on an area of 15.2 mm × 30.4 mm with a sample rate up to 1.2 kHz. It was used to investigate the contact pressures of vocal folds during phonation. This was performed in ex vivo experiments of 11 porcine larynges. The contact pressure at the medial surface and other phonation parameters, as the glottal resistance and the closing velocity of the vocal fold, were measured at different adduction and elongation levels and air flow rates. A statistical analysis was carried out. It could be shown that the contact pressure rises, when the vocal fold is manipulated or when the flow rate is increased.
During phonation, the vocal folds execute a complex movement. Related to the subglottal pressure and tension of the vocal folds themselves, this movement may differ, furthermore depending on the kind of phonation a collision between both vocal folds may occur. If the vocal folds are overstrained, this can cause lesions. To gain knowledge about the vocal folds movements and the way of their collisions, a high-speed evaluation unit for a pressure-mapping sensor was developed. The sensor brings along a local resolution of 27.6 measure points per square centimeter and with the developed unit an adjustable framerate up to 1 kHz can be realized. Due to a sensor thickness of about 0.2 mm, an integration into hemi-larynx flow experiments is quite simple without vigorous changes on the setup. Because of an unrestricted field of view it is possible to record the movements with a high-speed camera. These recordings will be correlated with contact pressures in the post processing. During these experiments, different flowrates of the excitation air and various abduction and elongation steps on the hemi-larynx are obtained to study the effect of those manipulations.
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