scholarly journals Steady streaming as a method for drug delivery to the inner ear

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Laura Sumner ◽  
Jonathan Mestel ◽  
Tobias Reichenbach
Keyword(s):  
Drug Delivery ◽  
Inner Ear ◽  
Hair Cells ◽  
Basilar Membrane ◽  
Fluid Dynamic ◽  
Nonlinear Process ◽  
Analytical Approximation ◽  
Sound Stimulation ◽  
Dynamic Simulations ◽  
Steady Streaming

AbstractThe inner ear, or cochlea, is a fluid-filled organ housing the mechanosensitive hair cells. Sound stimulation is relayed to the hair cells through waves that propagate on the elastic basilar membrane. Sensorineural hearing loss occurs from damage to the hair cells and cannot currently be cured. Although drugs have been proposed to prevent damage or restore functionality to hair cells, a difficulty with such treatments is ensuring adequate drug delivery to the cells. Because the cochlea is encased in the temporal bone, it can only be accessed from its basal end. However, the hair cells that are responsible for detecting speech-frequency sounds reside at the opposite, apical end. In this paper we show that steady streaming can be used to transport drugs along the cochlea. Steady streaming is a nonlinear process that accompanies many fluctuating fluid motions, including the sound-evoked waves in the inner ear. We combine an analytical approximation for the waves in the cochlea with computational fluid dynamic simulations to demonstrate that the combined steady streaming effects of several different frequencies can transport drugs from the base of the cochlea further towards the apex. Our results therefore show that multi-frequency sound stimulation can serve as a non-invasive method to transport drugs efficiently along the cochlea.

Prestin binding peptides as ligands for targeted polymersome mediated drug delivery to outer hair cells in the inner ear

2012 ◽  
Vol 424 (1-2) ◽  
pp. 121-127 ◽  
Author(s):  
Elena V. Surovtseva ◽  
Alexander H. Johnston ◽  
Weikai Zhang ◽  
Ya Zhang ◽  
Adele Kim ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Inner Ear ◽  
Hair Cells ◽  
Outer Hair Cells ◽  
Binding Peptides

Drug Delivery to the Inner Ear: Strategies and Their Therapeutic Implications for Sensorineural Hearing Loss

2012 ◽  
Vol 9 (3) ◽  
pp. 231-242 ◽  
Author(s):  
Teresa Rivera ◽  
Lorena Sanz ◽  
Guadalupe Camarero ◽  
Isabel Varela-Nieto
Keyword(s):  
Drug Delivery ◽  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Inner Ear ◽  
Sensorineural Hearing ◽  
Therapeutic Implications

Towards real-time fire data synthesis using numerical simulations

2021 ◽  
pp. 073490412199344
Author(s):  
Wolfram Jahn ◽  
Frane Sazunic ◽  
Carlos Sing-Long
Keyword(s):  
Real Time ◽  
Computational Fluid Dynamic ◽  
Dynamic Models ◽  
Fluid Dynamic ◽  
Near Field ◽  
Computing Time ◽  
Temperature Correction ◽  
Dynamic Simulations ◽  
Conservation Of Energy ◽  
Fire Scenarios

Synthesising data from fire scenarios using fire simulations requires iterative running of these simulations. For real-time synthesising, faster-than-real-time simulations are thus necessary. In this article, different model types are assessed according to their complexity to determine the trade-off between the accuracy of the output and the required computing time. A threshold grid size for real-time computational fluid dynamic simulations is identified, and the implications of simplifying existing field fire models by turning off sub-models are assessed. In addition, a temperature correction for two zone models based on the conservation of energy of the hot layer is introduced, to account for spatial variations of temperature in the near field of the fire. The main conclusions are that real-time fire simulations with spatial resolution are possible and that it is not necessary to solve all fine-scale physics to reproduce temperature measurements accurately. There remains, however, a gap in performance between computational fluid dynamic models and zone models that must be explored to achieve faster-than-real-time fire simulations.

scholarly journals Inner Ear and Muscle Developmental Defects in Smpx-Deficient Zebrafish Embryos

2021 ◽  
Vol 22 (12) ◽  
pp. 6497
Author(s):  
Anna Ghilardi ◽  
Alberto Diana ◽  
Renato Bacchetta ◽  
Nadia Santo ◽  
Miriam Ascagni ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Hair Cells ◽  
Muscle Fibers ◽  
Underlying Mechanism ◽  
Loss Of Function ◽  
Zebrafish Model ◽  
Developmental Defects ◽  
Inner Ear Development ◽  
Syndromic Hearing Loss

The last decade has witnessed the identification of several families affected by hereditary non-syndromic hearing loss (NSHL) caused by mutations in the SMPX gene and the loss of function has been suggested as the underlying mechanism. In the attempt to confirm this hypothesis we generated an Smpx-deficient zebrafish model, pointing out its crucial role in proper inner ear development. Indeed, a marked decrease in the number of kinocilia together with structural alterations of the stereocilia and the kinocilium itself in the hair cells of the inner ear were observed. We also report the impairment of the mechanotransduction by the hair cells, making SMPX a potential key player in the construction of the machinery necessary for sound detection. This wealth of evidence provides the first possible explanation for hearing loss in SMPX-mutated patients. Additionally, we observed a clear muscular phenotype consisting of the defective organization and functioning of muscle fibers, strongly suggesting a potential role for the protein in the development of muscle fibers. This piece of evidence highlights the need for more in-depth analyses in search for possible correlations between SMPX mutations and muscular disorders in humans, thus potentially turning this non-syndromic hearing loss-associated gene into the genetic cause of dysfunctions characterized by more than one symptom, making SMPX a novel syndromic gene.

scholarly journals Analysis of Radial Inflow Turbine Losses Operating with Supercritical Carbon Dioxide

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3561
Author(s):  
Antti Uusitalo ◽  
Aki Grönman
Keyword(s):  
Fluid Dynamic ◽  
Dynamic Simulations ◽  
Average Deviation ◽  
Loss Analysis ◽  
Specific Speed ◽  
Loss Models ◽  
Rotor Losses ◽  
Radial Turbines ◽  
Design Power ◽  
Good Agreement

The losses of supercritical CO2 radial turbines with design power scales of about 1 MW were investigated by using computational fluid dynamic simulations. The simulation results were compared with loss predictions from enthalpy loss correlations. The aim of the study was to investigate how the expansion losses are divided between the stator and rotor as well as to compare the loss predictions obtained with the different methods for turbine designs with varying specific speeds. It was observed that a reasonably good agreement between the 1D loss correlations and computational fluid dynamics results can be obtained by using a suitable set of loss correlations. The use of different passage loss models led to high deviations in the predicted rotor losses, especially with turbine designs having the highest or lowest specific speeds. The best agreement in respect to CFD results with the average deviation of less than 10% was found when using the CETI passage loss model. In addition, the other investigated passage loss models provided relatively good agreement for some of the analyzed turbine designs, but the deviations were higher when considering the full specific speed range that was investigated. The stator loss analysis revealed that despite some differences in the predicted losses between the methods, a similar trend in the development of the losses was observed as the turbine specific speed was changed.

scholarly journals Identification and characterization of amphibian SLC26A5 using RNA-Seq

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zhongying Wang ◽  
Qixuan Wang ◽  
Hao Wu ◽  
Zhiwu Huang
Keyword(s):  
Amino Acid ◽  
Inner Ear ◽  
Hair Cells ◽  
Rana Catesbeiana ◽  
Site Directed Mutagenesis ◽  
Amino Acid Residues ◽  
Rna Seq ◽  
American Bullfrog ◽  
Frog Species

Abstract Background Prestin (SLC26A5) is responsible for acute sensitivity and frequency selectivity in the vertebrate auditory system. Limited knowledge of prestin is from experiments using site-directed mutagenesis or domain-swapping techniques after the amino acid residues were identified by comparing the sequence of prestin to those of its paralogs and orthologs. Frog prestin is the only representative in amphibian lineage and the studies of it were quite rare with only one species identified. Results Here we report a new coding sequence of SLC26A5 for a frog species, Rana catesbeiana (the American bullfrog). In our study, the SLC26A5 gene of Rana has been mapped, sequenced and cloned successively using RNA-Seq. We measured the nonlinear capacitance (NLC) of prestin both in the hair cells of Rana’s inner ear and HEK293T cells transfected with this new coding gene. HEK293T cells expressing Rana prestin showed electrophysiological features similar to that of hair cells from its inner ear. Comparative studies of zebrafish, chick, Rana and an ancient frog species showed that chick and zebrafish prestin lacked NLC. Ancient frog’s prestin was functionally different from Rana. Conclusions We mapped and sequenced the SLC26A5 of the Rana catesbeiana from its inner ear cDNA using RNA-Seq. The Rana SLC26A5 cDNA was 2292 bp long, encoding a polypeptide of 763 amino acid residues, with 40% identity to mammals. This new coding gene could encode a functionally active protein conferring NLC to both frog HCs and the mammalian cell line. While comparing to its orthologs, the amphibian prestin has been evolutionarily changing its function and becomes more advanced than avian and teleost prestin.

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