Labyrinthine Structures Research Articles

Experimental validation of anomalous acoustic wave refraction using Double layered acoustic gratings

Acoustic metasurfaces (AMSs) have garnered increasing attention over the past decade due to their remarkable capability for wave manipulation. AMSs have been widely applied in diverse domains, including anomalous refraction and extraordinary sound absorption/isolation, among others. However, typical AMS designs, such as Helmholtz resonator-like or labyrinthine structures, are often geometrically complex, limiting their practical usability. In this paper, we introduce an ultracompact Double Layered Acoustic Grating (DLAG) to achieve anomalous acoustic wave refraction. The DLAG comprises double-layered rigid panels with multiple perforated subwavelength slits. By optimizing the positions of these slits on the rigid panels, the acoustic energy of an obliquely incident plane wave can be concentrated within a predetermined region in an arbitrary direction. The paper will first review the theoretical background to predict the wave propagation controlled by DLAGs based on the surface coupling approach. Subsequently, the underlying principle to achieve anomalous refraction using DLAGs will be discussed. A 3D-printed DLAG with the optimized slit positions is used for demonstration. In the experiment, the acoustic energy of a plane wave with an incident angle of 36 degrees was successfully collimated within a predetermined focusing region with a negative refracted angle of -36 degrees.

Proton-conducting membranes based on Nafion® synthesized by using nanodiamond platform

New method of emulsion synthesis of Nafion®-type copolymer composition by using nanodiamond platform has been proposed and implemented. Produced polymeric coagulate saturated with diamonds (4.1 % wt.) possessed increased ionic capacity of the copolymer comparative to the analogue without diamonds. SEM patterns for coagulate membranes showed labyrinthine structures with diamonds integrated into copolymer without any segregation. This structuring provided necessary elastic and strength properties of new type membranes for hydrogen fuel cells. In new membranes synchrotron experiments exhibited a network of ionic channels which ensured a proton conductivity by one order of magnitude higher than that for the analogue produced of premade components.

Low-frequency ultra-broadband ventilated muffler based on a resonance-labyrinthine metamaterial

We present a theoretical and experimental study of a ventilated metamaterial muffler operating at a low-frequency range. The muffler combines two Helmholtz resonance cavities with the spatial labyrinthine microstructures to achieve a large bandgap. A central hole ensures efficient air circulation. The adjustable cavity allows for precise control over the performance and bandwidth of sound insulation. By cascading multiple metamaterial units, the muffler exhibits a large transmission loss with broad bandwidth. Both simulations and experiments demonstrate transmission loss is over 10 dB in the frequency range from 230 Hz to 816 Hz. The overall dimensions of the muffler are 216 mm in length and 15 mm in diameter, much smaller than the operating wavelength. The high-efficiency sound insulation under the ventilation condition originates from local resonance with labyrinthine structures. This muffler exhibits potential for diverse applications in the field of acoustic engineering, where there is a demand for simultaneous noise reduction and ventilation.

Characterization of Magnetic Labyrinthine Structures Through Junctions and Terminals Detection Using Template Matching and CNN

Characterization of Magnetic Labyrinthine Structures Through Junctions and Terminals Detection Using Template Matching and CNN

Going round the bend: reflection and transmission of long waves by waveguide corners and labyrinths

Long-wave asymptotic approximations are developed for two-dimensional acoustic waves along rigid ducts. The waves are scattered by obstacles, constrictions, bulges and/or bends. Matched asymptotic expansions are used, requiring the calculation of blockage coefficients, which are defined in terms of the solution of related potential-flow problems. The emphasis is on estimating reflection and transmission coefficients, correct to first order in the ratio of the waveguide width to the wavelength. Detailed results are given for sharp bends of arbitrary angle, including right-angled bends and hairpin bends. Applications to multiple scattering by labyrinthine structures are also made.

Partial Labyrinth Removal Restricted to the Superior Semicircular Canal in Focal Combined Transpetrosal Approach: Description and Illustrative Cases.

The labyrinthine structures obstruct the surgical view of the deep petroclival region in the transpetrosal approach. Historically, labyrinthectomy and removal of all 3 semicircular canals, with resultant deafness, was used in patients with ipsilateral functional hearing deficits to improve access. The advent and systematization of superior and posterior semicircular canal removal (transcrusal approach) with good rates of hearing preservation has allowed a redefinition of the possibility of partial labyrinthectomy in patients without previous hearing deficits. The present manuscript is intended to describe a technical refinement of partial labyrinthectomy during focal combined petrosectomy, offering a customization of the approach through the selective removal of the superior semicircular canal for specific types of tumors. The use of the technique is demonstrated through surgical drawings, pictures, and videos. The rationale to indicate this new approach is discussed based on clinical cases. Three illustrative clinical cases (petroclival meningiomas) are demonstrated. Functional hearing on the approach side has been preserved in all of them. The focal combined transpetrosal approach associated with the superior semicircular canal resection has been a promising surgical technique in the treatment of selected petroclival tumors. It has the potential to further decrease the risks of postoperative auditory and vestibular dysfunctions associated with labyrinthectomies.

Ocular counter-roll during a Mŕnière’s attack: evidence of ictal utricle pathway imbalance using fundus photography (P3-9.004)

<h3>Objective:</h3> To call attention to unrecognized ictal vestibular manifestations of Mŕnière’s disease. <h3>Background:</h3> During Mŕnière’s disease (MD) attacks, static semicircular canal (SCC) asymmetry causes spontaneous nystagmus (ipsilesional when excitatory, and contralesional when inhibitory). Acute dynamic SCC dysfunction can cause an abnormal head impulse test (HIT, e.g., acute vestibular neuritis), although the HIT can be normal during a MD attack. Documentation of ictal otolith (utricle and saccule) dysfunction using vestibular evoked myogenic potentials (VEMPs) has rarely been reported. We describe the first case, to our knowledge, of a patient presenting with a Mŕnière’s attack in whom an ocular counter-roll (OCR, from static utricle pathway imbalance) was documented using fundus photography. <h3>Design/Methods:</h3> One case report of a patient with an OCR observed during a MD attack. <h3>Results:</h3> A 65-year-old man with known history of bilateral MD presented during a typical vertigo attack, and testing demonstrated: 1) Video-oculography (VOG) – spontaneous horizontal-torsional, unidirectional right beating nystagmus, following Alexander’s law; 2) Video HIT (vHIT) – low gain (0.49 where &lt;0.7 is considered abnormal) in the plane of the left horizontal SCC; 3) fundus photography – OCR with the top poles of both eyes rotated toward the left ear, in the absence of other features of the ocular tilt reaction (OTR, including OCR, head tilt, skew deviation). The HINTS exam (head impulse, nystagmus, test of skew) suggested a left peripheral vestibulopathy, and a Mŕnière’s attack was diagnosed given his history. Three weeks later testing was repeated while asymptomatic: 1) VOG – no nystagmus; 2) vHIT – normal horizontal SCC gain (0.73); 3) fundus photography – no OCR. For more, visit the NOVEL collection: https://collections.lib.utah.edu/ark:/87278/s6k97g27 <h3>Conclusions:</h3> Using a non-mydriatic fundus camera, we were able to document an ictal OCR in MD. Its presence suggested utricle pathway imbalance, offering insight into the labyrinthine structures that may be involved during a MD attack. <b>Disclosure:</b> Dr. Fracica has nothing to disclose. Dr. Gold has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Springer .

Frequency-tunable sound insulation via a reconfigurable and ventilated acoustic metamaterial

In acoustic engineering, sound-proofing ventilation barriers find wide applications in diverse situations. However, most of the structures only have responses with fixed frequencies and a very narrow frequency range, especially for low frequency acoustics. Here we show a subwavelength acoustic metamaterial based on labyrinthine structures, which possesses tunable sound insulation and ventilation properties. The Fano-like asymmetric transmission dips is formed by the interference between the resonant scattering of discrete states and the background scattering of continuous states. By adjusting the spacing between these two half zigzag molds, the sound insulation dip frequency can shift from 360 Hz to 575 Hz while the free ventilation area ratio is kept to over 36.3% and the total thickness is only about 0.06λ. Moreover, the noise peak frequency can be detected by a microphone detection and adaptive adjustment of the spacing with a small stepping motor is demonstrated, the results agree well with numerical simulations. We anticipate our design may find potential applications in acoustic air vents, soundproofing window and duct noise control.

Level set-based topology optimization for the design of labyrinthine acoustic metamaterials

We present a topology optimization method for the design of labyrinthine metamaterials with a large path length for acoustic wave propagation. An objective function maximizes the pressure gradient in an air-filled region at a low frequency, and a level set-based optimization method enables the optimal design of the labyrinthine structure with high computational efficiency owing to the concept of topological derivative. First, we explain the design settings of labyrinthine metamaterials. Next, the objective functions to obtain labyrinthine structures are introduced, and the corresponding topological derivatives are obtained. The optimization problem is formulated in the framework of the level set topology optimization method, and two-dimensional numerical examples are provided to demonstrate the validity of the proposed method. Based on the frequency responses of the effective parameters and dispersion analysis, the optimized designs are characterized by a negative refractive index over a wide frequency interval, which can be controlled by a parameter introduced in the objective function.

Injected 3T-3D-FLAIR-MRI labyrinthine patterns match with the severity and tonotopic alteration in sudden sensorineural hearing loss.

The aim of the study was to assess a correlation between MRI labyrinthine changes detected with IV-gadolinium optimized high-resolution 3D-FLAIR sequences 4h after injection (OPT4-3DFLAIR) and the type of SSNHL, in terms of frequency alteration and severity. This was a prospective monocentric study achieved from July 2019 to December 2020. The inclusion criterion was acute hearing loss of at least 30dB over three contiguous frequencies occurring within a 72-h period, documented by a pure-tone audiometry (PTA). The primary endpoint was the visual assessment of hyperintensity in labyrinthine structures on OPT4-3DFLAIR performed on 3T MRI. Thirty-six affected ears were included (20 men, 15 women; mean age: 54.5 ± 16.3years) with 69.4% full-spectrum hearing loss. The median hearing loss, expressed as median and interquartile range [IQR] was 91dB [74-120], with 47.2% of concomitant acute vestibular syndrome. Pathological signal was found in 26 out of 36 ears (72.2%). Basal turn enhancement was found in all abnormal MRIs, with 73.1% of apical turn enhancement and 50% of vestibular enhancement. Seventeen on 19 cases (89.5%) with apical involvement on MRI had low-frequency hearing loss. Vestibular involvement on MRI was significantly associated with a wider frequency range of hearing loss (p = 0.0002) and the severity of SSNHL (84.5 [71.7-92.5] dB versus 120 [85.8-120] dB, p = 0.0158). This report shows that in pathological MRI in SSNHL, a pathologic cochlear base signal is always detected, a cochlear apical turn enhancement matches with low-tone impairment, and a pathological signal within the posterior labyrinth is associated with an impairment of all frequencies and the severity of SSNHL.

Sol-gel system evolution control for the synthesis of gas-sensitive nanomaterials based on semiconductor oxides

The article analyzes conditions for the occurrence of spinodal decomposition in sol-gel systems based on semiconductor oxide precursors, resulting in labyrinthine structures. Such materials are promising for use in chemoresistive gas sensors with increased sensory response. It is shown that system evolution towards these structures is possible due to sol cooling, or increased its maturation time.

Shaping surfaces and interfaces of 2D materials on mica with intercalating water and ethanol

Interfaces between mica and graphene, as well as the transition metal dichalcogenides (TMDCs) MoS2 and WS2, were wetted with water and ethanol, and investigated employing scanning force microscopy and molecular dynamics (MD) simulations. Below 25% RH, water wets the graphene-mica interface with labyrinthine structures, exhibiting branch widths of about 50 nm for single layers of graphene, increasing to almost an order of magnitude more for four graphene layers. At mica-TMDC interfaces, water films exhibit a transition from labyrinthine to compact morphology upon going from single- to multi-layers of the TMDCs. Ethanol films show a compact morphology at all the interfaces, regardless of the number of 2D material layers on top. The film morphologies are attributed to an equilibrium between electrostatic repulsion of preferentially oriented molecular dipoles, and the line tension of the wetted areas, which is dominated by the deformation of the 2D materials at the edges of the wet areas. The compact front of the water wetting film under multilayers of TMDCs is attributed to a much larger bending stiffness of these materials than of graphene multilayers. The thickness dependent stiffness of the 2D materials may be employed to shape their surfaces from the nano- to the micrometer scale.

Labyrinthine Structure with Subwavelength and Broadband Sound Insulation

In this text, the combination of spiral structure and zigzag channels is introduced to design labyrinthine structures, in which sound waves can propagate alternately in the clockwise and counterclockwise directions. Finite element method and S-parameter retrieval method are used to calculate band structures, effective parameters, and transmission properties of the structures. The influences of different structural parameters on their acoustic properties are also studied. These results show labyrinthine structures have multiple bandgaps in the range of 0 Hz–1000 Hz, and the proportion of bandgaps exceeds 33%, which indicates labyrinthine structures have good broadband properties. The normalized frequency of the lowest bandgaps is far smaller than 1, which indicates the structures take good control of sound waves on subwavelength scale. Combining units with different structural parameters can achieve better sound insulation. This research provides a new kind of space-coiling structure for low-frequency and broadband sound waves control, which have excellent application prospects.

Patterns in magnetic granular media at the crossover from two to three dimensions.

We perform three-dimensional particle-based simulations of confined, vibrated, and magnetizable beads to study the effect of cell geometry on pattern selection. For quasi-two-dimensional systems, we reproduce previously observed macroscopic patterns such as hexagonal crystals and labyrinthine structures. For systems at the crossover from two to three dimensions, labyrinthine branches shorten and are replaced by triplets of beads forming upright triangles which self-organize into a herringbone pattern. This transition is associated with increases in both translational and orientational orders.

Enhanced Fractional Acoustic Vortices by an Annulus Acoustic Metasurface with Multi‐Layered Rings

AbstractAn annulus acoustic metasurface (AAM) with multi‐layered rings is proposed to achieve the enhanced fractional acoustic vortices (FAVs). It is found that the enhancement of the transmitted FAV through the AAM is sensitive to the radial interval between adjacent ring‐structures. A greatly enhanced FAV is theoretically obtained by the optimized AAM. Then finite element models based on composite labyrinthine structures are established and the generation of the enhanced FAV is confirmed by simulations. Furthermore, the optimized AAM samples are fabricated and experimentally generate the enhanced FAV with topological charge of 1.5. The FAV generated by the optimized AAM with three‐rings is ≈5.4 times stronger than that generated by the classical AAM with one‐ring. Finally, experimental results show that the greatly enhanced FAV can capture micro‐particles and rotate a sound absorbing disk easily. The greatly enhanced FAV by the AAM may be more efficient for the micro‐particle manipulation, edge‐detection image, and acoustic communication.

One Way or Another

One Way or Another

A probabilistic atlas of the human inner ear's bony labyrinth enables reliable atlas-based segmentation of the total fluid space.

Intravenous contrast agent-enhanced magnetic resonance imaging of the endolymphatic space (ELS) of the inner ear permits direct, in-vivo, non-invasive visualization of labyrinthine structures and thus verification of endolymphatic hydrops (ELH). However, current volumetric assessment approaches lack normalization. The aim of this study was to develop a probabilistic atlas of the inner ear's bony labyrinth as a first step towards an automated and reproducible volume-based quantification of the ELS. The study included three different datasets: a source dataset (D1) to build the probabilistic atlas and two testing sets (D2, D3). D1 included 24 right-handed patients (12 females; mean age 51.5 ± 3.9years) and D2 5 patients (3 female; mean age 48.8 ± 5.01years) with vestibular migraine without ELH or any measurable vestibular deficits. D3 consisted of five patients (one female; mean age 46 ± 5.2years) suffering from unilateral Menière's disease and ELH. Data processing comprised three steps: preprocessing using an affine and deformable fusion registration pipeline, computation of an atlas for the left and right inner ear using a label-assisted approach, and validation of the atlas based on localizing and segmenting previously unseen ears. The three-dimensional probabilistic atlas of the inner ear's bony labyrinth consisted of the internal acoustic meatus and inner ears (including cochlea, otoliths, and semicircular canals) for both sides separately. The analyses showed a high level of agreement between the atlas-based segmentation and the manual gold standard with an overlap of 89% for the right ear and 86% for the left ear (measured by dice scores). This probabilistic in vivo atlas of the human inner ear's bony labyrinth and thus of the inner ear's total fluid space for both ears represents a necessary step towards a normalized, easily reproducible and reliable volumetric quantification of the perilymphatic and endolymphatic space in view of MR volumetric assessment of ELH. The proposed atlas lays the groundwork for state-of-the-art approaches (e.g., deep learning) and will be provided to the scientific community.

Non-human labyrinths: Roots and additional other than human formation methods

Abstract Within the context of exploring new electronic arts' aesthetic regions and unexampled connections between generative art, games and mythology, my practical artistic research was led to focus on labyrinthine structures as exquisite legendary spatial gaming devices and as possible pathways to gain deeper humane insights, resulting into discoveries of original methods of labyrinth formation by means other than human. Labyrinths and mazes are inextricable paths, human made millennial structures that provide spatial challenges often connected with feedback, compression, entanglement and hyper complexification of goal oriented displacement. They are perhaps the most ancient example of structure for spatial and serious games. Novel methods for labyrinth creation – non-human methods – are introduced and exemplified through artistic constructs. These new methods utilize non-human bioelectronic techniques and are initially grouped into three distinct sub-categories: the 'open' method, the 'mathematical flower' method, the 'animal' method. Four case examples of artistic non-human labyrinths resorting to the introduced novel methods are explored: k. video games (2007, 2010), Wolfanddotcom video game (2017), 8-bit Maze Gardens vegetable paintings (2018–present), Ant Ennae Labyrinths bio-electronic apparatus (2019–present).

Etiology-Specific Mineralization Patterns in Patients with Labyrinthitis Ossificans.

Our aim was to identify whether specific patterns of ossification in labyrinthitis ossificans are associated with the known risk factors. Labyrinthitis ossificans has been described as sequela of prior temporal bone trauma, prior infection, and other disorders including sickle cell disease. Specific patterns of mineralization in the membranous labyrinth associated with these risk factors has not been previously described. This was a retrospective study evaluating temporal bone CT scans at our institution from November 2005 to May 2018 in patients with labyrinthitis ossificans. Membranous labyrinthine structures evaluated for ossification included the following: basal, middle, and apical cochlear turns; lateral, posterior, and superior semicircular canals; and the vestibule for both ears in all patients. These structures were assigned a severity score, 0-4, based on degree of mineralization. Clinical records were reviewed for potential labyrinthitis ossificans risk factors. Basic descriptive statistics and a mixed model were used to correlate the degree and patterns of ossification with clinical history. Forty-four patients (58 ears) with labyrinthitis ossificans were identified and evaluated. The most common risk factors were chronic otomastoiditis (n = 18), temporal bone surgery (n = 9), temporal bone trauma (n = 6), sickle cell disease (n = 5), and meningitis (n = 4). For all etiologies, the semicircular canals were most severely affected, and the vestibule was the least. In patients with prior temporal bone surgery, significantly greater mineralization was seen in the basal turn of the cochlea (P = .027), the vestibule (P = .001), and semicircular canals (P < .001-.008). No significant pattern was identified in patients with meningitis, sickle cell disease, or trauma. Significant patterns of mineralization in labyrinthitis ossificans were observed in patients with prior temporal bone surgery. For all etiologies, the semicircular canals were most severely affected. No significant mineralization pattern was observed in patients with chronic otomastoiditis, meningitis, sickle cell disease, or prior temporal bone trauma.

Big brother’s little sister: the ideological construction of women’s super league

This article explores the structure and culture of the Football Association (FA) in relation to the development of England’s first semiprofessional female soccer league—Women’s Super League (WSL). Through observations and interviews, we examined the planning and operationalization of WSL. Drawing on critical feminist literature and theories of organizational change, we demonstrate the FA’s shift from tolerance of the women’s game, through opposition, to defining and controlling elite female club football as a new product shaped by traditional conceptualizations of gender. The labyrinthine structures of the FA abetted the exclusion of pre-WSL stakeholders, allowing the FA to fashion a League imagined as both qualitatively different to elite men’s football in terms of style of play, appealing to a different fan base, yet inextricably bound to men’s clubs for support. It concludes by providing recommendations for how organizational change might offer correctives to the FA approach to developing WSL.