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Article ; Online: An Investigation of Acoustic Back-Coupling in Human Phonation on a Synthetic Larynx Model

Christoph Näger / Stefan Kniesburges / Bogac Tur / Stefan Schoder / Stefan Becker

Bioengineering, Vol 10, Iss 12, p

2023 Volume 1343

Abstract: In the human phonation process, acoustic standing waves in the vocal tract can influence the fluid flow through the glottis as well as vocal fold oscillation. To investigate the amount of acoustic back-coupling, the supraglottal flow field has been ... ...

Abstract	In the human phonation process, acoustic standing waves in the vocal tract can influence the fluid flow through the glottis as well as vocal fold oscillation. To investigate the amount of acoustic back-coupling, the supraglottal flow field has been recorded via high-speed particle image velocimetry (PIV) in a synthetic larynx model for several configurations with different vocal tract lengths. Based on the obtained velocity fields, acoustic source terms were computed. Additionally, the sound radiation into the far field was recorded via microphone measurements and the vocal fold oscillation via high-speed camera recordings. The PIV measurements revealed that near a vocal tract resonance frequency f R , the vocal fold oscillation frequency f o (and therefore also the flow field’s fundamental frequency) jumps onto f R . This is accompanied by a substantial relative increase in aeroacoustic sound generation efficiency. Furthermore, the measurements show that f o - f R -coupling increases vocal efficiency, signal-to-noise ratio, harmonics-to-noise ratio and cepstral peak prominence. At the same time, the glottal volume flow needed for stable vocal fold oscillation decreases strongly. All of this results in an improved voice quality and phonation efficiency so that a person phonating with f o - f R -coupling can phonate longer and with better voice quality.
Keywords	human phonation ; source–filter interaction ; particle image velocimetry ; synthetic larynx model ; transmission line model ; aeroacoustic source computation ; Technology ; T ; Biology (General) ; QH301-705.5
Subject code	535
Language	English
Publishing date	2023-11-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Real-time tracking of drug binding to influenza A M2 reveals a high energy barrier

Kumar Tekwani Movellan / Melanie Wegstroth / Kerstin Overkamp / Andrei Leonov / Stefan Becker / Loren B. Andreas

Journal of Structural Biology: X, Vol 8, Iss , Pp 100090- (2023)

2023

Abstract: The drug Rimantadine binds to two different sites in the M2 protein from influenza A, a peripheral site and a pore site that is the primary site of efficacy. It remained enigmatic that pore binding did not occur in certain detergent micelles, and in ... ...

Abstract	The drug Rimantadine binds to two different sites in the M2 protein from influenza A, a peripheral site and a pore site that is the primary site of efficacy. It remained enigmatic that pore binding did not occur in certain detergent micelles, and in particular incomplete binding was observed in a mixture of lipids selected to match the viral membrane. Here we show that two effects are responsible, namely changes in the protein upon pore binding that prevented detergent solubilization, and slow binding kinetics in the lipid samples. Using 55–100 kHz magic-angle spinning NMR, we characterize kinetics of drug binding in three different lipid environments: DPhPC, DPhPC with cholesterol and viral mimetic membrane lipid bilayers. Slow pharmacological binding kinetics allowed the characterization of spectral changes associated with non-specific binding to the protein periphery in the kinetically trapped pore-apo state. Resonance assignments were determined from a set of proton-detected 3D spectra. Chemical shift changes associated with functional binding in the pore of M2 were tracked in real time in order to estimate the activation energy. The binding kinetics are affected by pH and the lipid environment and in particular cholesterol. We found that the imidazole-imidazole hydrogen bond at residue histidine 37 is a stable feature of the protein across several lipid compositions. Pore binding breaks the imidazole-imidazole hydrogen bond and limits solubilization in DHPC detergent.
Keywords	Magic-angle spinning ; Proton channel ; Drug binding ; Solid-state NMR ; Binding kinetics ; Biology (General) ; QH301-705.5
Subject code	500
Language	English
Publishing date	2023-12-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Multivalent Tau/PSD-95 interactions arrest in vitro condensates and clusters mimicking the postsynaptic density

Zheng Shen / Daxiao Sun / Adriana Savastano / Sára Joana Varga / Maria-Sol Cima-Omori / Stefan Becker / Alf Honigmann / Markus Zweckstetter

Nature Communications, Vol 14, Iss 1, Pp 1-

2023 Volume 13

Abstract: Abstract Alzheimer’s disease begins with mild memory loss and slowly destroys memory and thinking. Cognitive impairment in Alzheimer’s disease has been associated with the localization of the microtubule-associated protein Tau at the postsynapse. However, ...

Abstract	Abstract Alzheimer’s disease begins with mild memory loss and slowly destroys memory and thinking. Cognitive impairment in Alzheimer’s disease has been associated with the localization of the microtubule-associated protein Tau at the postsynapse. However, the correlation between Tau at the postsynapse and synaptic dysfunction remains unclear. Here, we show that Tau arrests liquid-like droplets formed by the four postsynaptic density proteins PSD-95, GKAP, Shank, Homer in solution, as well as NMDA (N-methyl-D-aspartate)-receptor-associated protein clusters on synthetic membranes. Tau-mediated condensate/cluster arrest critically depends on the binding of multiple interaction motifs of Tau to a canonical GMP-binding pocket in the guanylate kinase domain of PSD-95. We further reveal that competitive binding of a high-affinity phosphorylated peptide to PSD-95 rescues the diffusional dynamics of an NMDA truncated construct, which contains the last five amino acids of the NMDA receptor subunit NR2B fused to the C-terminus of the tetrameric GCN4 coiled-coil domain, in postsynaptic density-like condensates/clusters. Taken together, our findings propose a molecular mechanism where Tau modulates the dynamic properties of the postsynaptic density.
Keywords	Science ; Q
Subject code	571
Language	English
Publishing date	2023-10-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: On the Alignment of Acoustic and Coupled Mechanic-Acoustic Eigenmodes in Phonation by Supraglottal Duct Variations

Florian Kraxberger / Christoph Näger / Marco Laudato / Elias Sundström / Stefan Becker / Mihai Mihaescu / Stefan Kniesburges / Stefan Schoder

Bioengineering, Vol 10, Iss 12, p

2023 Volume 1369

Abstract: Sound generation in human phonation and the underlying fluid–structure–acoustic interaction that describes the sound production mechanism are not fully understood. A previous experimental study, with a silicone made vocal fold model connected to a ... ...

Abstract	Sound generation in human phonation and the underlying fluid–structure–acoustic interaction that describes the sound production mechanism are not fully understood. A previous experimental study, with a silicone made vocal fold model connected to a straight vocal tract pipe of fixed length, showed that vibroacoustic coupling can cause a deviation in the vocal fold vibration frequency. This occurred when the fundamental frequency of the vocal fold motion was close to the lowest acoustic resonance frequency of the pipe. What is not fully understood is how the vibroacoustic coupling is influenced by a varying vocal tract length. Presuming that this effect is a pure coupling of the acoustical effects, a numerical simulation model is established based on the computation of the mechanical-acoustic eigenvalue. With varying pipe lengths, the lowest acoustic resonance frequency was adjusted in the experiments and so in the simulation setup. In doing so, the evolution of the vocal folds’ coupled eigenvalues and eigenmodes is investigated, which confirms the experimental findings. Finally, it was shown that for normal phonation conditions, the mechanical mode is the most efficient vibration pattern whenever the acoustic resonance of the pipe (lowest formant) is far away from the vocal folds’ vibration frequency. Whenever the lowest formant is slightly lower than the mechanical vocal fold eigenfrequency, the coupled vocal fold motion pattern at the formant frequency dominates.
Keywords	voice production ; fluid-structure-acoustic interaction ; mechanical-acoustical eigenvalue simulation ; vocal fold motion ; finite element model ; Technology ; T ; Biology (General) ; QH301-705.5
Subject code	780
Language	English
Publishing date	2023-11-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Experimental Study of the Influence of the Adsorbate Layer Composition on the Wetting of Different Substrates with Water

Michaela Heier / Rolf Merz / Stefan Becker / Kai Langenbach / Michael Kopnarski / Hans Hasse

Adsorption Science & Technology, Vol

2021 Volume 2021

Abstract: Wetting is strongly influenced by adsorbate layers, which are omnipresent on surfaces. The influence of the composition and thickness of adsorbate layers on the water contact angle of sessile drops on different substrates was systematically investigated ... ...

Abstract	Wetting is strongly influenced by adsorbate layers, which are omnipresent on surfaces. The influence of the composition and thickness of adsorbate layers on the water contact angle of sessile drops on different substrates was systematically investigated in the present work. Measurements were carried out for gold-sputtered substrates. These new results are compared to results from a previous study, in which corresponding measurements were carried out for technical steel and titanium substrates. In all experiments, different pretreatments of the samples were used to obtain variations of the adsorbate layer. The samples were either exposed to an oil bath or not, and different cleaning agents were used. The analysis of the adsorbate layer was carried out with X-ray photoelectron spectroscopy (XPS). The results for the different substrates reveal that the water contact angle depends mainly on the composition of the adsorbate layer. The substrate has only an indirect influence, as it influences the composition of the adsorbate layer. The thickness of the adsorbate layers was between 1.4 and 14 nm and was large enough to prevent a direct influence of the substrate on the water contact angle. It is shown that using the information on the adsorbate layer composition from XPS and the results for the water contact angle obtained for the gold samples alone, the water contact angles on the steel and titanium samples can be predicted.
Keywords	Physical and theoretical chemistry ; QD450-801
Subject code	530
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	Hindawi - SAGE Publishing
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Proline/arginine dipeptide repeat polymers derail protein folding in amyotrophic lateral sclerosis

Maria Babu / Filippo Favretto / Alain Ibáñez de Opakua / Marija Rankovic / Stefan Becker / Markus Zweckstetter

Nature Communications, Vol 12, Iss 1, Pp 1-

2021 Volume 7

Abstract: The most frequent cause of familial Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD) are hexanucleotide repeat expansions in the non-coding region of the C9ORF72 gene that are translated into five dipeptide repeat (DPR) proteins. ... ...

Abstract	The most frequent cause of familial Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD) are hexanucleotide repeat expansions in the non-coding region of the C9ORF72 gene that are translated into five dipeptide repeat (DPR) proteins. Here, the authors show that proline/arginine (PR) DPRs inhibit the prolyl isomerase PPIA and reveal the molecular mechanism of the impaired protein folding activity of PPIA by performing NMR measurements and determining a PR DPR bound PPIA crystal structure.
Keywords	Science ; Q
Language	English
Publishing date	2021-06-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Drone Noise Emission Characteristics and Noise Effects on Humans—A Systematic Review

Beat Schäffer / Reto Pieren / Kurt Heutschi / Jean Marc Wunderli / Stefan Becker

International Journal of Environmental Research and Public Health, Vol 18, Iss 5940, p

2021 Volume 5940

Abstract: The number of operations of Unmanned Aerial Vehicles (UAV), commonly referred to as “drones”, has strongly increased in the past and is likely to further grow in the future. Therefore, drones are becoming a growing new source of environmental noise ... ...

Abstract	The number of operations of Unmanned Aerial Vehicles (UAV), commonly referred to as “drones”, has strongly increased in the past and is likely to further grow in the future. Therefore, drones are becoming a growing new source of environmental noise pollution, and annoyance reactions to drone noise are likely to occur in an increasing share of the population. To date, research on drone noise emission characteristics, and in particular also on health impacts, seems scarce, but systematic overviews on these topics are missing. The objective of this study was to establish a systematic literature review on drone noise emissions and noise effects on humans. The paper presents the methodology of the systematic reviews performed separately for noise emission and noise effects, assembles current literature, gives an overview on the state of knowledge, and identifies research gaps. Current literature suggests that drone noise is substantially more annoying than road traffic or aircraft noise due to special acoustic characteristics such as pure tones and high-frequency broadband noise. A range of open questions remains to be tackled by future studies.
Keywords	drones ; UAV ; UAS ; multicopter ; noise emission ; noise effects ; Medicine ; R
Subject code	710
Language	English
Publishing date	2021-06-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Geometry of the Vocal Tract and Properties of Phonation near Threshold

Lewis Fulcher / Alexander Lodermeyer / George Kähler / Stefan Becker / Stefan Kniesburges

Applied Sciences, Vol 9, Iss 13, p

Calculations and Measurements

2019 Volume 2755

Abstract: In voice research, analytically-based models are efficient tools to investigate the basic physical mechanisms of phonation. Calculations based on lumped element models describe the effects of the air in the vocal tract upon threshold pressure ( P th ) by ...

Abstract	In voice research, analytically-based models are efficient tools to investigate the basic physical mechanisms of phonation. Calculations based on lumped element models describe the effects of the air in the vocal tract upon threshold pressure ( P th ) by its inertance. The latter depends on the geometrical boundary conditions prescribed by the vocal tract length (directly) and its cross-sectional area (inversely). Using Titze’s surface wave model (SWM) to account for the properties of the vocal folds, the influence of the vocal tract inertia is examined by two sets of calculations in combination with experiments that apply silicone-based vocal folds. In the first set, a vocal tract is constructed whose cross-sectional area is adjustable from 2.7 cm 2 to 11.7 cm 2 . In the second set, the length of the vocal tract is varied from 4.0 cm to 59.0 cm. For both sets, the pressure and frequency data are collected and compared with calculations based on the SWM. In most cases, the measurements support the calculations; hence, the model is suited to describe and predict basic mechanisms of phonation and the inertial effects caused by a vocal tract.
Keywords	analytical vocal fold model ; fluid–structure interaction ; vocal tract inertia ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	410
Language	English
Publishing date	2019-07-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: FACS-Based Functional Protein Screening via Microfluidic Co-encapsulation of Yeast Secretor and Mammalian Reporter Cells

Desislava Yanakieva / Adrian Elter / Jens Bratsch / Karlheinz Friedrich / Stefan Becker / Harald Kolmar

Scientific Reports, Vol 10, Iss 1, Pp 1-

2020 Volume 13

Abstract: Abstract In this study, we present a straightforward approach for functional cell-based screening by co-encapsulation of secretor yeast cells and reporter mammalian cells in millions of individual agarose-containing microdroplets. Our system is ... ...

Abstract	Abstract In this study, we present a straightforward approach for functional cell-based screening by co-encapsulation of secretor yeast cells and reporter mammalian cells in millions of individual agarose-containing microdroplets. Our system is compatible with ultra-high-throughput selection utilizing standard fluorescence-activated cell sorters (FACS) without need of extensive adaptation and optimization. In a model study we co-encapsulated murine interleukin 3 (mIL-3)-secreting S. cerevisiae cells with murine Ba/F3 reporter cells, which express green fluorescent protein (GFP) upon stimulation with mIL-3, and could observe specific and robust induction of fluorescence signal compared to a control with yeast cells secreting a non-functional mIL-3 mutant. We demonstrate the successful enrichment of activating mIL-3 wt-secreting yeast cells from a 1:10,000 dilution in cells expressing the inactive cytokine variant by two consecutive cycles of co-encapsulation and FACS. This indicates the suitability of the presented strategy for functional screening of high-diversity yeast-based libraries and demonstrates its potential for the efficient isolation of clones secreting bioactive recombinant proteins.
Keywords	Medicine ; R ; Science ; Q
Subject code	570
Language	English
Publishing date	2020-06-01T00:00:00Z
Publisher	Nature Publishing Group
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Sound Radiation of Aerodynamically Excited Flat Plates into Cavities

Johannes Osterziel / Florian J. Zenger / Stefan Becker

Applied Sciences, Vol 7, Iss 10, p

2017 Volume 1062

Abstract: Flow-induced vibrations and the sound radiation of flexible plate structures of different thickness mounted in a rigid plate are experimentally investigated. Therefore, flow properties and turbulent boundary layer parameters are determined through ... ...

Abstract	Flow-induced vibrations and the sound radiation of flexible plate structures of different thickness mounted in a rigid plate are experimentally investigated. Therefore, flow properties and turbulent boundary layer parameters are determined through measurements with a hot-wire anemometer in an aeroacoustic wind tunnel. Furthermore, the excitation of the vibrating plate is examined by laser scanning vibrometry. To describe the sound radiation and the sound transmission of the flexible aluminium plates into cavities, a cuboid-shaped room with adjustable volume and 34 flush-mounted microphones is installed at the non flow-excited side of the aluminium plates. Results showed that the sound field inside the cavity is on the one hand dependent on the flow parameters and the plate thickness and on the other hand on the cavity volume which indirectly influences the level and the distribution of the sound pressure behind the flexible plate through different excited modes.
Keywords	aeroacoustics ; flow-excited ; vibration ; sound radiation ; acoustic coupling ; turbulent ; boundary layer ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	621
Language	English
Publishing date	2017-10-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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