bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the resonance response of a system of two ultrasound-driven lipid encapsulated microbubbles
Authors: Yusefi Hossein , Helfield Brandon
Published: May 2022

Ultrasound-stimulated microbubbles are clinical imaging agents and being developed for therapeutic applications. Here, we aim to understand the behaviour of two individual phospholipid-encapsulated microbubbles in close proximity to each other, typically the case given clinical doses. We developed a finite element model to study the radial resonance response of each microbubble within a two-microbubble system from 1–8 MHz with bubble diameters ranging from 2 to 4 μm, bubble center-to-center distances h = 8–24 μm, and peak-negative pressures of 30–45 kPa. For two identical microbubbles, our results show the frequency of maximum response (fMR) decreases (7%–10%) and the amplitude of maximum response (AMR) increases (9%–11%) as the microbubbles approach one another. For a two-bubble system of different microbubble sizes, the larger microbubble shows no change in fMR and a slight shift of AMR (2–3%). However, the smaller microbubble exhibits an increase in fMR (7–11%) and a significant decrease of AMR (38–52%). Furthermore, when in very close proximity (h = 8 μm), smaller bubbles exhibit a secondary resonance peak corresponding to the fMR of the larger bubble with amplitudes comparable to its primary resonance peak. Our work suggests that microbubble resonance behaviour is greatly affected by the presence of nearby bubbles, which has implications in imaging and therapy.
Recent developments in fetal lung ultrasound
Authors: Ghorayeb Sleiman R. , Blitz Matthew J. , Bracero Luis A.
Published: May 2022

Fetal ultrasound has been employed for years to help evaluate fetal growth and development and to monitor pregnancy. Furthermore, fetal lung maturity has been assessed pre-natally by examination of the amniotic fluid, usually obtained by transabdominal amniocentesis, for lecithin, lecithin/sphingomyelin ratio, or “P” factor (fluorescent polarization measurement for lipids.) Quantitative ultrasound texture analysis of fetal lung has been proposed in previous studies as a promising noninvasive method to predict fetal lung maturity, fetal lung hypoplasia, and neonatal respiratory morbidity. This technique utilizes standard fetal lung images, which are easily obtained by sonographers during routine ultrasound examinations. Additional information then can be extracted from these images by applying quantitative processing methods that characterize the tissue. This presentation discusses how to differentiate preterm (<37 weeks of gestation) from term (≥37 weeks of gestation) fetal lungs by quantitative texture analysis of ultrasound images. This quantification is based on the extent of heterogeneity associated with lung maturity by employing a unique, novel noninvasive technique to determine the Heterogeneity Index (HI) in ultrasound images. The HI values are then compared in sonograms of immature lungs with mature lungs. Conceptual advances for the possibility of integrating this technology in handheld ultraportable systems for point-of-care ultrasound (POCUS) are also presented.
Ultrasound at the pulmonary air-tissue interface: Mechanism of haemorrhage induction and implications for safe use of diagnostic and therapeutic lung ultrasound applications
Authors: Wolfram Frank , Gutsche Holger , Lesser Thomas G.
Published: May 2022

Despite the high-diagnostic value of sonographic lung imaging, providing substantial patient benefit, clinician should be aware that ultrasound exposure on lung is not absolutely without risk of harm. As shown in animal models, lung ultrasound (LUS) even in the diagnostic regime can induce pulmonary capillary haemorrhage (PCH) at the alveolar epithelium-gas interface. Acoustic peak negative pressure in the range of 1.0–1.5 MPa correlates well with PCH threshold. However, in retrospective human studies, adverse events could not be demonstrated following LUS examination, which is evidence of symptomatic PCH after therapeutic ultrasound ablation in proximity of lung exists. Therefore, this subject remains controversial. This work summarizes the underlying physical causes and consequences of ultrasound induced PCH. The complexity of PCH thresholds depending on imaging modes, pathological lung conditions including ventilation parameters will be presented. In addition, current recommendations for the safe use of LUS based on Safety Indices given by AIUM and EFSUMB guidelines and the impact of LUS specific settings, available on modern scanners, will be discussed.
Ensuring the kids are alright: Ways to help students network with industry professionals in the age of virtual meetings and career fair disillusionment
Authors: Harne Ryan L.
Published: May 2022

The pandemic has derailed the traditional networking vehicles to connect aspiring, ambitious students with industry professionals. As a result, the flow of young talent to best-fitting industry outlets is being misdirected. Moreover, many students are not inclined to accept virtual meetings as a replacement for face-to-face engagement while professionals often prefer virtual meetings as means to maximize productivity. The latter disparity has led to campus “career fairs” turning into stay-at-home experiences that students notoriously lament. Without bridges to network students with the right industry professionals to optimize hiring and onboarding processes, our society faces increasing early career turnover, loss of productivity, and disenchantment of young talent with the technical outlets that could await them. This talk will first clarify the crisis facing industries as a result of pandemic-motivated physical distancing practices. We will discuss lessons learned from recent attempts to foster genuine connections between students and the industry professionals they could work alongside in the future. The talk will conclude with a call to action on part of both students and professionals to collectively rebuild the networking system before a temporary disruption turns into a generational failure.
Where does an airport end? Civic considerations of acoustics as practiced
Authors: Betchkal Davyd H. , McFarland Scott
Published: May 2022

In the United States, Federal agencies work on behalf of the public within domains defined relative to their purpose (i.e., mission). The mission of most agencies—and certainly land management agencies—includes a spatial manifestation. Legal authorities shape the practice of acoustics for use in decision-making, but often without reciprocal influence from scientists in the field. As a consequence, the propagation of sound complicates many legal constructions of space. In this talk, we consider a spatial contradiction that results in an avoidable problem: misuse of Day-Night Level (Ldn) to estimate residual sound level in natural areas. We resolve the contradiction by offering a standard alternative, ANSI/ASA S12.100-2014 “Methods to define and measure the residual sound in protected natural and quiet residential areas.”
Focus boom simulations using sBOOM and lossy nonlinear Tricomi equation solvers
Authors: Rallabhandi Sriram
Published: May 2022

The low-boom prediction committee, comprised of several research agencies and companies across the world, is organizing a special session dedicated to the prediction and comparison of focused sonic booms. This presentation will document and discuss focus boom simulations corresponding to the benchmark cases prescribed for this special session using a combination of sBOOM and lossy nonlinear Tricomi equation (LNTE) solvers. sBOOM is an augmented Burgers equation based sonic boom propagation solver that has been developed at NASA over the past decade. Focus boom simulations involve regions where simulations based solely on traditional ray theory approaches, such as those used in sBOOM, are inadequate. The results from sBOOM are, therefore, coupled with an LNTE solver that considers diffraction effects, which become dominant in the vicinity of imaginary surfaces (caustics) in the atmosphere on which singularities arise when using ray theory approaches. The LNTE solver used in this study has been developed and successfully demonstrated as part of the NASA's superboom caustic analysis and measurement project (SCAMP). Sonic boom focused signatures and other relevant metrics of the coupled simulations will be documented and discussed along with interesting observations.
Contribution to the definition of a simple focusing test case and ONERA results for the two test cases of the sonic boom focusing predictions special session
Authors: Carrier Gérald , Coulouvrat François
Published: May 2022

For usual cruise flight conditions, the prediction of the sonic boom on ground caused by an aircraft flying supersonically can be predicted numerically by ray tracing codes according to the geometrical acoustics hypotheses. Such codes account for the non-linear and dissipative (thermoviscous and molecular relaxation) effects that occur during the propagation from flight level down to the ground by solving dissipative Burgers' equations along the rays, accounting for the evolution of the ray tube area. Such an approach is not applicable to predict the pressure waveform in the neighbourhood of a caustics that can be generated by the cusp of the focussing pressure wave generated under specific unsteady flight conditions of the aircraft. For such focussing conditions, the pressure waveform can be modelled by the Tricomi equations. The BANGV code has been used to predict the pressure waveforms in focussing conditions of the sonic boom focusing predictions special session of the 182nd ASA meeting. The results obtained for the two test-cases will be presented in this paper to be compared to other participants' results and contribute to the validation of numerical simulation methods of focussing boom.
Vortex beam interactions for the measurement of nonlinear acoustic behaviour
Authors: Richard Grace , Cochran Sandy , Spalding Gabriel , Lavery Martin
Published: May 2022

Spatially shaped optical fields have been widely implemented for remote sensing, enhanced imaging and communications. Many of these principles can be readily translated into acoustics, where acoustic fields that carry orbital angular momentum (OAM) have gained considerable interest in recent years. These spatially shaped fields can provide unique acoustic interactions with materials and gasses as they propagate that can be leveraged to create novel sensor technologies. We will present a technique to amplify the visibility of nonlinear acoustic effects in gasses, via the controlled interference of acoustic pulses that carry OAM. This amplification allows accurate determination of the nonlinear parameter with acoustic pressures that are 66dB lower than a direct measurement of pulse chirping. In controlled conditions, non-linear parameters can be directly measured; however, variations in environmental parameters can lead to ambiguity, which can be addressed through the use of a trained Support Vector Machine machine learning approach. This will allow measurements in variation in the nonlinear parameter 0.01 with over 99.5% accuracy and 0.001 with over 75% accuracy based on single measurements, where repeated measurements can further reduce the power requirements and increase accuracy. This approach can be used for monitoring changes in air quality and if extended to other frequencies could be used for monitoring fatiguing in metals.
Active holographic tweezers based on spiraling interdigitated transducers
Authors: Baudoin Michael , Al Sahely Roudy , Gong Zhixiong , Bou Matar Olivier , Gerbedoen Jean-Claude , Smagin Nikolay , Chutani Ravinder
Published: May 2022

Recently, our team demonstrated the selective manipulations of microparticles [Baudoin et al., Sci. Adv. 5, eaav1967 (2019)] and cells [Baudoin et al., Nat. Commun. 11, 4244 (2020)] in a standard microscopy environment with active holographic tweezers based on spiraling interdigitated transducers. In this talk, we will present (i) the ultra-high frequency (250 MHz) selective manipulation of 4 μm beads with nanoNewton forces and (ii) first results on the the 3D manipulation of particles and in particular their axial displacement without any motion of the transducer, by tuning the driving frequency [Gong et al., Phys. Rev. Appl. 16, 024034 (2021)]. We will also introduce a new mixed finite element/angular spectrum code, which enables to understand the underlying physic and opens perspectives to improve the tweezers design.
Physiological sensitivity to across-channel temporal patterns in response to Schroeder harmonic complexes, based on sequence rather than coincidence detection
Authors: Lu Hsin-Wei , Smith Philip H. , Joris Philip X.
Published: May 2022

The flat-envelope harmonic complexes devised by Schroeder (1970) contain a linear frequency sweep whose direction and speed depend on phase curvature C. Physiological studies have focused on responses at a given characteristic frequency (CF), which show only a subtle dependence on the sign and magnitude of C. The question arises whether CNS neurons are sensitive to the temporal pattern across nerve fibers differing in CF. Octopus cells in the cochlear nucleus receive convergent excitatory input from nerve fibers spanning a wide range of CFs and are thought to be monaural coincidence detectors. We studied their spike output and membrane responses to Schroeder complexes in anesthetized gerbils. Octopus cells were indeed tuned to a wide frequency range but showed discrete frequency “hotspots” of differing strength. Most cells showed marked sensitivity to C, with some neurons preferring upward and others downward frequency sweeps, which was broadly stable across SPL and fundamental frequency. The sensitivity to C arises not from coincidence detection, but from a sensitivity to the temporal sequence of activation of inputs tuned to different frequencies. We conclude that marked sensitivity to Schroeder phase exists at the first CNS processing stage and is based on temporal sequence detection across frequency channels.
Children with amblyaudia show less flexibility in auditory cortical entrainment to periodic non-speech sounds
Authors: Momtaz Sara , Moncrieff Deborah , Ray Meredith , Bidelman Gavin
Published: May 2022

We investigated auditory temporal processing in children with amblyaudia (AMB), a subtype of auditory processing disorder, via cortical neural entrainment. Evoked responses were recorded to click-trains at slow versus fast (8.5 versus 14.9/sec) rates in n = 14 children with AMB and n = 11 age-matched controls. Source and time-frequency analyses decomposed EEGs into oscillations (reflecting neural entrainment) stemming from the bilateral auditory cortex. Phase-locking strength in AMB depended critically on the speed of auditory stimuli. In contrast to age-matched peers, AMB responses were largely insensitive to rate manipulations. This rate resistance was seen regardless of the ear of presentation and in both cortical hemispheres. Children with AMB show a stark inflexibility in auditory cortical entrainment to rapid sounds. In addition to reduced capacity to integrate information between the ears, we identify a new functional characterization of AMB in the form of more rigid tagging of external auditory stimuli. Our neurophysiological findings may account for certain temporal processing deficits commonly observed in AMB and related auditory processing disorders (APDs) behaviorally. More broadly, our findings may inform communication strategies and future rehabilitation programs; increasing the rate of stimuli above a normal (slow) speech rate is likely to make stimulus processing more challenging for individuals with AMB/APD.
Incorporation of acoustic black hole stiffeners into composite airframes for reduction of noise radiation
Authors: Moorhouse Anna , Shepherd Micah , Beck Benjamin S.
Published: May 2022

Stiffened composite panels are commonly used in aerospace structures, because they are lightweight, while maintaining a high load-bearing ability. However, their high stiffness-to-mass ratio makes them efficient noise radiators. In rotorcraft cabins made with composite panels, for example, the internal noise levels can be quite high such that pilot and passenger communication and comfort are disrupted. This has led to a need for innovative noise reduction strategies for composite rotorcraft panels. A specialized stiffener, which incorporates the acoustic black hole (ABH) effect into the cross section, is proposed to improve the damping of stiffened composite panels. By incorporating the damping concept into the stiffeners, the panel’s radiated noise can be reduced while maintaining the weight advantages and panel strength. To determine the advantages and trade-offs of this concept, numerical models have been developed and incorporated into an optimization scheme. Computational studies reveal promising results from the optimized ABH stiffeners as compared to a baseline panel with traditional stiffeners.
Acoustic analog of twisted bilayer graphene
Authors: Craig Steven R. , Li Zhenglu , Ruan Jiawei , Louie Steven G. , Shi Chengzhi
Published: May 2022

The emergence of twistronics in bilayer graphene has inspired the creation of new phononic structures that translate quantum effects into macro systems. Here, we introduce an acoustic analog of twisted bilayer graphene that is built with 3D-printed star arrays confined in a two-dimensional acoustic waveguide. The lattices on the top and bottom of the waveguide are coupled by spoof surface acoustic waves. Like its quantum counterpart, the twisting angle of the structure influences wave propagation within the system and its resulting band structures. In analytical models, full-wave simulations, and experiments, we observe mode localization at magic twisting angle that hosts the flat bands. We also study other twisted bilayers with different twisting angles to compare with the magic-angle results. The observation of unusual twistronics effects in acoustic systems demonstrates the potential to identify new quantum materials with simplified acoustic models.
Optimization methods in design of locally resonant metamaterials for noise and vibration mitigation
Authors: Juros Klara , Kras Aleksander , Kamisinski Tadeusz
Published: May 2022

In recent years, acoustic metamaterials are broadly investigated especially for noise and vibration mitigation. For this purpose, the best-suited option are locally resonant metamaterials (LRS). By creation of a band gap effect in flexural wave propagation in structure, improve its Sound Transmission Loss (STL). The effectiveness of the structure in STL and vibration mitigation depends on several different parameters for example mass of the base structure to LRS mass ratio distances between resonators or its geometry. Many different shapes of LRS can lead to band gap for selected frequency range but with many different results when it comes to STL. Most of the solutions presented in recent years were based on simple beam resonators tuned to a selected frequency, and barely ever the geometrical optimization process of the resonator’s shape was considered. This project investigates optimization methods of the LRS presented in the literature, considering their efficiency and geometrical shape. Several algorithms were selected and combined with a numerical simulation process to obtain a solution with optimized mass and STL. Measurements for selected optimized structures are compared with simulation results and discussed in detail.
Tagged-MRI to audio synthesis with a pairwise heterogeneous deep translator
Authors: Liu Xiaofeng , Xing Fangxu , Stone Maureen , Prince Jerry L. , Kim Jangwon , El Fakhri Georges , Woo Jonghye
Published: May 2022

Identifying the underlying relationship between visual movements in tagged-MRI and intelligible speech is a vital problem to better understand speech production in health and disease. Due to their heterogeneous representations, however, direct mapping between the two modalities is challenging. We develop a deep learning framework that can synthesize a sequence of tagged MRI data to its corresponding mel-spectrogram, and then convert back into the audio waveform. Our network adopts a parallel encoder-decoder structure to take as input a pair of tagged MRI sequences. The 3D CNN-based encoders learn to extract the feature of spatiotemporally varying motions. The decoder then learns to generate the corresponding spectrograms conditioned on the latent space feature. For the pair of the same utterance, we further make the latent space feature as close as possible with the Kullback-Leibler divergence. To demonstrate the performance of our framework, we used a leave-one-out evaluation strategy on a total of 63 tagged MRI sequences from two utterances, including 43 “ageese” and 20 “asouk.” Our framework enabled the generation of clear audio given a sequence of tagged MRI unseen in training, which could potentially aid in better understanding speech production and improving treatment strategies for patients with speech-related disorders.
Learnability of ultrasound tongue imaging devices in speech-language pathology
Authors: Marcoux Isabelle , Ménard Lucie , Laporte Catherine
Published: May 2022

Ultrasound tongue imaging has shown potential for speech-language pathologists (SLPs) to evaluate and treat persistent articulatory disorders. However, SLPs typically begin with low to no familiarity with ultrasound. Thus, this study investigated an important aspect of ultrasound device usability: learnability for SLPs. The project was funded by an NSERC Engage grant in partnership with Clarius Mobile Health. Twelve SLPs learned to use two ultrasound devices: a wireless device, provided by our partner Clarius, and a traditional device, to record clips of their or the experimenter’s tongue. They then completed a questionnaire (French translation of the System Usability Scale (Brooke, 1996)). Two expert judges evaluated the clips recorded by the SLPs for the choice of settings and the positioning of the probe. Results of the SUS show a better usability for the wireless device than the traditional device. SLPs appreciated the user-friendly tablet interface, possibly because they are already used to interacting with tablets. Clips analyses show a better choice of settings by the SLPs with the wireless device. The positioning of the probe, however, was better with the traditional device, possibly due to its smaller probe. In conclusion, US seems to have a good potential of usability in speech-language pathology, provided that SLPs receive training for US image interpretation. A traditional US device may require a longer learning period than a wireless model with tablet interface.
Communication behavior observation
Authors: Klockgether Stefan , Kleinstein Conradin , Schneeberger Michael , Derleth R. Peter
Published: May 2022

Communication is one of the most important aspects of human society. Humans have developed several strategies to successfully communicate in challenging acoustic environments. Some of these strategies can be consciously controlled while in a conversation, but others happen unconsciously or as a mixture of both. To investigate communication behavior, real two-person conversations were observed in the Sonova Real Life Lab. Within the lab, participants were allowed to move around freely in an acoustic scene. The head position and orientation of both participants were monitored with a motion capturing system and the voices of both participants were recorded with wireless headset microphones. The voice intensity and spectral content were analyzed from the speech recordings to assess vocal effort and detect Lombard speech. The audio setup of the Real Life Lab was used to playback an acoustic background scene, which could be directly manipulated in level and spectral content. This contribution shows data from pilot experiments in which the participants had to communicate in acoustically controlled background scenes. The data show the characteristics of and interactions between different strategies humans use to successfully communicate in challenging acoustic environments. Learnings for future experiments are discussed.
Use of towed array reverberation data for rapid environmental assessment
Authors: Ellis Dale D.
Published: May 2022

Towed array reverberation beam time series can provide information about the underwater acoustic environment by providing a snapshot of the scattering in both range and bearing. By mapping time into range and beam angle into azimuth, John Preston pioneered the use of polar plots to survey an area [Preston et al., J. Acoust. Soc. Am., 87,119–134 (1991)]. When the polar plot is superimposed on the bathymetry of an area, a scattering map can be made. High scattering is generally associated with bottom features. With additional analysis and modeling, bottom loss and scattering strengths can be obtained [Preston and Ellis, J. Marine Systems 78, S359–S371 (2009)]. This talk emphasizes results from the rapid environmental assessment (REA) Rapid Response exercises 1996–1998, a multi-nation collaboration organized by NATO MILOC (military oceanography). While transmission loss experiments along a single radial could take hours, a single charge dropped near the towed array gave information on all radials in just minutes. Anomalies could be immediately identified, for investigation by more precise techniques. The REA exercises attracted interest and led to the Boundary Characterization and Clutter Joint Research Projects between CMRE (the NATO Centre for Maritime Research and Experimentation), Canada, and US. [Work supported by ONR.]
Environmentally constrained modeling of mid-frequency transmission loss and reverberation measured during the Target and Reverberation Experiment 2013
Authors: Hefner Brian T. , Yang Jie , Tang Dajun
Published: May 2022

The goal of the Target and Reverberation Experiment (TREX13) was to make contemporaneous measurements of mid-frequency (1.5–4 kHz) transmission loss and reverberation with extensive environmental measurements so detailed model/data comparison can be achieved and important environmental factors can be identified for different applications. APL-UW collaborated with ARL-Penn State, led by John R. Preston, to deploy the Five Octave Research Array (FORA) on a “clothesline” about 2.1 m above the seafloor. This fixed-source/receiver configuration helped eliminate uncertainties from the motion of a towed array and allow reverberation measurement along a narrow, 7-km-long section of seafloor. The experiment site had a fairly complex spatial distribution of both sediment type and sediment scattering properties and keeping the FORA in a fixed position was instrumental in understanding and modeling the reverberation. While soft sediments make up only 27% of the sediments by area at the site, it is necessary to account for this spatial dependence so that both transmission loss and reverberation can be modeled using a consistent set of environmental inputs. These models and their implications for our understanding of the environmental factors which most impact mid-frequency reverberation will be discussed. [Work supported by the U.S. Office of Naval Research.]
The Littoral Continuous Active Sonar Multi-National Joint Research Project 2014–2020
Authors: LePage Kevin D. , Tesei Alessandra , Biagini Stefano , lourey simon , murphy stefan , Bates Jeffrey , Inglis Gary , Hines Paul C. , Wood Gary , Smith Catherine L. , Manzari Vicenzo , Terracciano Daniele , van Walree Paul , Grimmett Doug , Abraham Doug
Published: May 2022

One of John Preston's achievements during his career was the hosting of multinational sonar experimentation efforts whilst a scientist at SACLANTCEN. The Littoral Continuous Active Sonar Multi-National Joint Research Project is the most recent international collaborative experimentation activity focused on sonar hosted by NATO STO Centre for Maritime Research and Experimentation, SACLANTCEN's sucessor. Between 2014 and 2020 LCAS brought scientists and engineers from 7 NATO and Partner Nations together with the CMRE to evaluate the effectiveness of continuous active sonar in shallow littoral environments. In this talk, the objectives of the project are laid out, the scientific issues and experimental approach reviewed, details about the four sea trials conducted under LCAS are presented, and a summary of the major results of the project is provided.
The legacy of the five octave research array and its impact on future towed array development
Authors: Smith Chad M. , Dorminy Jim
Published: May 2022

The five octave research array (FORA) was developed and implemented in support of the Office of Naval Research (ONR) Ocean Acoustics program’s experimental efforts. Dr. John R. Preston spearheaded planning, development, and experimental operations of this well-known acquisition system. Planning and development of the system took place between 1997 and 2002, while engineering assessment and array enhancements continued through 2004. From initial delivery to the Penn State Applied Research Laboratory to the present, the FORA made possible over 20 very successful sea trials. These trials were primarily in the interest of oceanographic and underwater acoustics, as well as signal processing research. The data collected, with John at the helm, fostered hundreds (if not thousands) of scholarly works, while John’s collaborative nature allowed an enormous number of researchers and students to benefit from the data and experience in at-sea experimentation. One of John’s final contributions was to renew planning and discussions for a replacement research array to continue in place of the aging FORA, which was becoming less dependable and increasingly expensive to maintain. This talk will discuss the development and history of the FORA, its involvement in a selection of collaborative ONR trials, and the FORA replacement acquisition system.
Go’s and no-go’s towards more correct reverberation room measurements of absorption
Authors: Vorlaender Michael , Balint Jamilla
Published: May 2022

Measurements of random-incidence absorption coefficients have been hotly contested since the ASA was founded in 1929. Yes, you read correctly, since 1929! Theories, explanations, myths, and strange interpretations appear, disappear, and reappear over the decades. What is wrong with this method of measurement? This paper discusses some of the methodological difficulties and reasons for discrepancies when comparing results between different reverberation chambers. It also presents possibilities arising from recent developments, such as the isotropy and angle dependence of the sound field incident on the absorber, the multi-exponential model for calculating decay times, and reference absorbers.
Measuring angle-dependent sound absorption in ordinary rooms
Authors: Nolan Mélanie
Published: May 2022

The effective use of sound absorbing materials in room acoustical design requires the use of angle-dependent coefficients, as opposed to random incidence coefficients, to properly account for the dissipation of sound energy at the room's boundary. In this study, a method is proposed for measuring the angle-dependent surface impedance and absorption coefficient of a boundary material in situ, in an ordinary room. The proposed method relies on the reconstruction of the pressure and normal particle velocity at the boundary using a plane-wave decomposition of the sound field measured with an array of microphones. In sufficiently reverberant environments, where sound strikes the material from nearly all directions in space, the angle-dependent properties of the boundary can be obtained simultaneously for all angles of incidence, from a single source position. In addition, the proposed methodology enables us to identify the specific directions of incidence on the material and makes it possible to estimate its operational acoustic performance. The validity of the method is examined experimentally in a reverberation chamber and in a classroom, using a robotic arm to scan the sound field in the vicinity of an absorbing boundary. Consistent absorption data are measured for various source positions and room configurations.
Non-negative surface contributions for cavities based on sound energy density
Authors: Gurbuz Caglar , Marburg Steffen
Published: May 2022

Surface and panel contribution analysis provides a useful methodology to identify sources of radiated sound in cavities. In commercial software, contribution analyses are performed by considering the sound pressure at an internal point. For visualization, a bar chart is usually supplied for the vibrating surfaces. The current solution has two major drawbacks: At first, the traditional technique provides only results for surfaces which are in motion. At second, the sound pressure depends on the location of the field point, which can lead to a deteriorated performance in regions with low pressure values. It is our aim to present non-negative surface contributions for sound energy density in a cavity. Energy-based contributions provide further insight into the characteristics of cavities, as they provide a holistic evaluation of sound pressure and particle velocity. For this, the boundary element method is applied to solve the Helmholtz equation for interior problems. In close analogy to the non-negative intensity, the energy-based contributions are determined from a quadratic form in order to bypass cancellation effects. Results show that regions with high contributions to the energy density are effectively recovered. Some of these surfaces appear almost inactive if the contributions are analyzed only with respect to sound pressure. As such, the evidence from this study suggests that energy-based surface contributions provide an effective quantity to identify sound sources, particularly for regions with low pressure values.
Perception at the extreme: Adaptive vocal-motor behavior of bats at high speed flight and in groups
Authors: Kloepper Laura , Weesner Alexandra , Bentley Ian
Published: May 2022

In order to successfully navigate through their environments without collisions at often high speeds, bats rely on two things: successful reconstruction of their environment from returning echoes and motor outputs in response to intermittent sensory information. This depends on the coordination between sensory input and locomotive output. Many bats regularly form dense aggregations in the wild and fly at speeds exceeding 100 km/h, likely posing significant sensorimotor challenges. We recorded the echolocation and flight behavior of wild frequency-modulated (FM) bats as they exited and returned to their cave roost to understand how bats coordinate flight and echolocation when faced with sensory challenges. We found that when exiting the roost in groups, many bats coordinate flight behavior and wingbeat movement with nearby conspecifics, but based on heading delays, this coordination is likely not driven by acoustic cues and instead may be guided by aerodynamic cues. During high-speed roost re-entry, bats modify echolocation signals consistent with increasing object discrimination as they approach the roost, yet adjustments in flight behavior do not coincide with the reception of echoes, suggesting that bats may be combining information from multiple pulses or senses to plan their flight path. [Work supported by ONR N000141612478 and NSF-IIBR-1916850.]
Echosounding in estuaries: Lessons learned from operations and data in four coastal systems
Authors: Bassett Christopher , Lavery Andone C.
Published: May 2022

The properties and dynamics of estuarine environments often exhibit strong spatial gradients and rapidly evolving structure that can be difficult to sample and resolve. High-frequency acoustic backscattering techniques spanning from 10 s to 100 s of kilohertz are well-suited for estuarine studies given that they can provide synoptic imaging, aid in discriminating between sources of acoustic backscattering, and in some cases quantify variables of interest. Here, we compare acoustic backscattering measurements obtained using vessel-based, towed, and underwater vehicle operations from the Columbia River, Connecticut River, James River, and Mobile Bay. These data are supported by other oceanographic measurements and circulation models. The sources of backscattering observed across these sites include bubbles, turbulent microstructure, stratification, suspended sediment, and biology. We focus on the quantification of and discrimination between areas dominated by unique processes, in addition to lessons learned regarding frequency selection and operations in estuarine environments.
Relating fine-grained sediment consolidation to acoustic seabed surveying
Authors: Stark Nina , Jaber Reem , Smith Liz , Massey Grace , Calantoni Joseph
Published: May 2022

The process of fine-grained seabed sediment consolidation is governed by a variety of factors including grain size distributions, organics, sediment dynamics, and anthropogenic activities (e.g., marine traffic and dredging). Poorly consolidated sediments are typically softer and more susceptible to mobility from shear, while over consolidated sediments are typically stiffer with a higher threshold for mobility from shear. Knowledge of the state of consolidation of seabed sediments is important to assess and maintain navigable depth, predict length scales of seafloor roughness, and assess seabed-object interaction (e.g., anchors, unexploded ordnance). For example, the porosity varies significantly for the same type of sediment for different states of consolidation. Variability is expected and has been qualitatively demonstrated in acoustic seabed surveying including high- and low-frequency techniques. In this study, seabed sediments were characterized using a portable free fall penetrometer along with geotechnical and sedimentological laboratory testing of fine-grained seabed sediments. Testing results quantified both sediment textural (e.g., bulk density, water content, void ratio, and porosity) and strength properties (e.g., undrained shear strength and consolidation state and behavior) and were related to the backscatter intensity observed with different high- and low-frequency off-the-shelf acoustic surveying devices.
Estimating geoacoustic properties of sediments with a wide grain-size distribution using sediment organic content and the viscous grain shearing model
Authors: Venegas Gabriel R. , Frey Madeline R. , Lee Kevin M. , Ballard Megan , Clemo W. Cyrus , Dorgan Kelly M.
Published: May 2022

Interstitial organic matter (OM) is a ubiquitous constituent of marine sediment, particularly prevalent in sediments with significant silt/clay fractions, and is often quantified across a wide range of disciplines. OM suspends silt and clay particles in the sediment matrix, adsorbs onto mineral surfaces, and resides primarily between mineral contacts, all of which are hypothesized to alter geoacoustic properties, yet OM has not been included in sediment acoustics models. Recent studies have shown that OM content (OC) correlates well with sediment geoacoustic properties, such as porosity and index of impedance, from sediments found in the Baltic Sea to seagrass-bearing sediments in Texas to mud banks in Brazil. In Mobile Bay, Alabama, OC correlated well not only with porosity and index of impedance, but also with grain-shearing coefficients described by the viscous grain shearing (VGS) model. Using empirical regressions derived from a subset of the Mobile Bay biogeoacoustic data and VGS, OC will be used to estimate geoacoustic properties of Mobile Bay sediments with a wide grain-size distribution. The efficacy and potential of using OC to predict sediment geoacoustic properties (and vice versa) in Mobile Bay and in other sediments with similar composition will be discussed. [Work supported by ONR.]
Ultrasound-enhanced drug delivery to spinal cord tumors
Authors: Smith Paige , Choi Min , Charron Danielle , Ramesh Ranjith , O'Reilly Meaghan
Published: May 2022

The blood-brain barrier (BBB) and blood-spinal cord barrier (BSCB) are major obstacles to the treatment of CNS diseases and disorders as they prevent the passage of most therapeutic agents from the blood pool to the CNS tissue. Transient, reversible opening of the BBB using ultrasound and microbubbles (MBs) has been extensively studied and has reached clinical investigations. Ultrasound and MBs can similarly modify the BSCB, although applications in the spinal cord have received less attention. We have previously demonstrated ultrasound and MB-mediated opening of the BSCB in rodents, as well as in large animals through the intact spine, using a spine-specific pulse scheme called short-burst phase keying (SBPK). In this talk, we will discuss our work evaluating treatment control approaches for controlling SBPK exposures and will present recent results from drug delivery studies in rodent models of primary and metastatic spinal cord tumors.
Ultrasound-targeted microbubble cavitation increases paracellular gaps in an in vitro blood brain barrier model
Authors: Conway Grace E. , Paranjape Anurag N. , Chen Xucai , Villanueva Flordeliza S.
Published: May 2022

Background: Ultrasound-targeted microbubble cavitation (UTMC) can transiently open the blood brain barrier (BBB). We sought to determine the timeline of paracellular gap formation after UTMC in an in vitro model of the BBB. Methods: We utilized a transwell model with murine brain endothelial cells (EC) and astrocytes on opposite sides of a support membrane. Ultrasound (1 MHz, 10 μs duration, 10 ms pulse interval) at 250 kPa was applied to lipid microbubbles in contact with ECs for 20 s. Z-stacks of transwells acquired by confocal microscopy were converted to maximum intensity projections to quantify number and size of paracellular gaps (NIS-Elements). Endothelial barrier function was assessed using transendothelial electrical resistance (TEER). One-way ANOVA with post-hoc t-testing was performed. Results: Compared to no UTMC, there was an increase in the number and size of paraceullar gaps two minutes after UTMC that lasted at least 60 min (p < 0.05). The increase in gaps was associated with a decrease in TEER (p < 0.05). The number of gaps started to decrease 15 min after UTMC, and total gap area started to decrease 30 min after UTMC (p < 0.05). Conclusions: In our model of the BBB, UTMC induces endothelial hyperpermeability, which appears mediated by dynamic paracellular gap formation.
Genetic and Antigenic Characterization of an Expanding H3 Influenza A Virus Clade in U.S. Swine Visualized by Nextstrain
Authors: Neveau Megan N. , Zeller Michael A. , Kaplan Bryan S. , Souza Carine K. , Gauger Phillip C. , Vincent Amy L. , Anderson Tavis K.
Published: May 2022

Genetically distinct clades of influenza A virus (IAV) in swine undermine efforts to control the disease. Swine producers commonly use vaccines, and vaccine strains are selected by identifying the most common hemagglutinin (HA) gene from viruses detected in a farm or a region.
Deploying anIn VitroGut Model to Assay the Impact of the Mannan-Oligosaccharide Prebiotic Bio-Mos on the Atlantic Salmon (Salmo salar) Gut Microbiome
Authors: Kazlauskaite Raminta , Cheaib Bachar , Humble Joseph , Heys Chloe , Ijaz Umer Zeeshan , Connelly Stephanie , Sloan William T. , Russell Julie , Martinez-Rubio Laura , Sweetman John , Kitts Alex , McGinnity Philip , Lyons Philip , Llewellyn Martin S.
Published: May 2022

In this paper we report the results of the impact of a prebiotic (alpha-MOS supplementation) on microbial communities, using anin vitrosimulator of the gut microbial environment of the Atlantic salmon. Our data suggest that Bio-Mos may be of value in salmonid production as it enhances volatile fatty acid production by the microbiota from salmon pyloric ceca and correlates with a significant shift in microbial community composition with observed increase in lactic acid producingCarnobacterium.
Lipopolysaccharide-pretreated mesenchymal stem cell-conditioned medium optimized with 10 kDa filter attenuates the injury of H9c2 cardiomyocytes in a model of hypoxia/reoxygenation
Authors: Wang Dan , Wen Jing-Yi , Wu Di , Ying Zi-Yue , Wen Zhi-Min , Peng Hui-Qian , Geng Cong , Feng Yuan-Bo , Sui Zhi-Gang , Lv Hui-Yi , Wu Jun , Xu Bing
Published: May 2022

Mesenchymal stem cell-derived conditioned medium (MSC-CM) improves cardiac function, which is partly attributed to the released paracrine factors. Since such cardioprotection is moderate and transient, it is essential that MSC-CM's effective components are optimized to alleviate myocardial injury. To optimize MSC-CM, MSCs were treated with or without lipopolysaccharides (LPSs) for 48 h (serum-free), and the supernatant was collected. Then, LPS-CM (MSC stimulated by LPS) was further treated with LPS remover (LPS Re-CM) or was concentrated with a 10 kDa cutoff filter (10 kDa-CM). Enzyme-linked immunosorbent assay showed that all the pretreatments increased the levels of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and insulin growth factor (IGF) except LPS Re-CM; 10 kDa-CM was superior to the other CMs. Cell Counting Kit-8 displayed that the viability of injured H9c2 cells was enhanced with the increase in the MSC-CM concentration. We also found that the 10 kDa-CM significantly alleviated H9c2 hypoxia/reoxygenation (H/R) injury, as evidenced by the increased Bcl-2/Bax ratio, and decreased the levels of lactate dehydrogenase and cardiac troponin. Transmission electron microscopy (TEM), TdT-mediated dUTP nick-end labelling (TUNEL), and hematoxylin and eosin staining (H&E) confirmed that 10 kDa-CM inhibited H/R-induced H9c2 morphological changes. Proteomic analysis identified 41 differentially expressed proteins in 10 kDa-CM, among which anti-inflammation, proangiogenesis, and antiapoptosis were related to cardiac protection. This study indicates that 10 kDa-CM protects H9c2 cardiomyocytes from H/R injury by preserving most of the protective factors, such as VEGF, HGF, and IGF, in MSC-CM.
Dynamic disorder in a coupled two-lane exclusion process with Langmuir kinetics
Authors: Garg Shaweta , Dhiman Isha
Published: May 2022

In intracellular transport, the motor proteins may jump between the filaments due to structural deformity where the motion is hindered by presence of bound proteins. This motivates us to study a system of two parallel disordered exclusion processes with Langmuir kinetics under symmetric and asymmetric coupling conditions. Theoretically, continuum mean-field approximation is employed to obtain steady-state equations which are further solved numerically. The steady-state system dynamics are examined for different values of coupling constant [Formula: see text], which indicates ratio of lane-changing rates. The effect of binding constant [Formula: see text] and defect parameters is also explored. Under the symmetric coupling case, the topological structure of phase diagram turns out to be similar to that in single-lane model, which differs significantly under fully asymmetric coupling. The asymmetric coupling increases magnitude of difference between densities in two lanes. At a very large attachment/detachment rate, the LK dynamics dominate the effect of asymmetric coupling in the lanes. The defect parameters are found to reduce particle flux in the steady state. The numerical results are validated through extensive Monte Carlo simulation.