bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical investigation of effects of lip stiffness on reed oscillation in a single-reed instrument
Authors: Yoshinaga Tsukasa , Yokoyama Hiroshi , Shoji Tetsuro , Miki Akira , Iida Akiyoshi
Published: June 2021

The sound of a single-reed instrument is produced by the interactions among flow, reed oscillation, and acoustic resonance in the resonator. To investigate the effects of lip stiffness on the reed oscillation and acoustic propagation in the single-reed instrument, we conduct a flow simulation coupled with a dynamic beam analysis. The flow and acoustic fields are simulated by solving the three-dimensionalNavier–Stokes equations, while the geometry of the instrument is expressed by the volume penalization method in the computational grids. The lip force on the reed is modeled as a function proportional to the distance between the lip position and reed surface, and the coefficient of lip stiffness was changed in the simulation. The mouthpiece of the instrument was set in the pressure chamber. The results showed that the self-sustained oscillation of reed started by adjusting the initial pressure condition of the chamber without the lip force, and amplitudes of the reed displacement decreased until a stable condition by adding the lip force. The lip stiffness was found to affect the amplitude of reed displacement, indicating the necessity of controlling the lip force to obtain stable oscillation.
Soundscape design for people with dementia; The correlation between psychoacoustic parameter and human perception of safety and mood
Authors: Talebzadeh Arezoo , Botteldooren Dick
Published: June 2021

In its base, soundscape design has a human-centred approach to the acoustic environment by putting a person's perception at the heart of the design process. The goal is to improve people's quality of life and well-being through sonic environments. The soundscape approach becomes complex when designing for people with cognitive complexities. It is critical to find ways to understand the connection between soundscape and people's responses. In this research, a personalized soundscape is designed based on recognizable sounds that give persons with dementia clues regarding time and place. Research has shown the positive effect of natural and non-natural soundscape on people with cognitive difficulties. Adding recognizable sounds to the soundscape gives people a feeling of safety, elevates their mood and activates them. The soundscape then will be evaluated by persons with dementia or their caregivers for necessary adjustment. The sound's evaluation process depends on the sound's physical characteristics, the psychoacoustic parameter of sound, and the person's cognition and psychological state. The research looks at the psychoacoustic parameter of evaluated sounds (sharpness, loudness, and roughness) concerning a sense of safety and improving the mood. The goal is to find a correlation between these parameters and sound selection to improve the process and enhance people's quality of life through soundscape design.
Sound walking Chicago's waterways
Authors: Keane Linda N.
Published: June 2021

What are the creative possibilities of studying soundscape ecology as citizen scientists for raising engagement with and stewardship of urban health and freshwater? Utilizing everyday technology of sound walks and recordings of Chicago's waterways, students explore sonic layers of interconnections between life in the atmosphere, geosphere, lithosphere, and hydrosphere. Citizen scientists open noise and liquid definitions of health, learning the history of Chicago's development and imagining the past, present, and future biodiversity of life. Sound walking and analysis of various Chicago sites in the loop, along the river, in parks, at the world's largest filtration plant, and along the lakefront, change understanding and begin new strategies of stewardship. Public and private partnerships with college students, Chicago public school students, Friends of the Chicago River, Chicago Line Cruises, and architectural and ecological researchers share advocacy with diverse audiences through exhibits, installation proposals, water workshops, and field trips. Hush City recordings, Radio Aporee Chicago Maps, sound emporiums, water workshops, tender house Installations, and Eco-Cruises on the river connect the public with the criticality of listening to the health of the city.
The analysis of west coast arrivals for secondary sonic booms
Authors: Riegel Kimberly A. , Sparrow Victor W.
Published: June 2021

During certain atmospheric conditions, sonic boom noise that normally would travel away from the ground is refracted back down toward the ground. This occurs for booms that have been emitted from the top of a supersonic aircraft or already bounced off the ground. These types of sonic boom arrivals are called secondary sonic booms or Over The Top (OTT) booms and can be audible more than 100 km away from the flight path. It is expected that these secondary sonic booms will impact the coastline even for flights that are only flying over water. Therefore, these OTT booms need to be well understood for future supersonic aircraft approaching coastal airports. Previous work by the authors has confirmed the findings of Rickley and Pierce for OTT booms of Concorde approaching the U.S. east coast. The present work employs the PCBoom software and will provide simulations of aircraft approaching U.S. west coast airports during all seasons to predict areas where noise may be heard. [Work supported by the FAA. The opinions, findings, conclusions and recommendations expressed in this material are those of the authors and do not necessarily reflect the views of ASCENT FAA Center of Excellence sponsor organizations.]
Minimal time to determine moving sound source direction in patients with sensorineural hearing loss
Authors: Klishova Evgenia , Gvozdeva Alisa , Sitdikov Vladimir , Golovanova Larisa , Andreeva Irina
Published: June 2021

Minimal time to determine the direction of azimuthal motion was measured in normally hearing subjects and in patients with sensorineural hearing loss (SNHL). A moving sound image was formed by counter-directional change of the amplitude on two loudspeakers placed at 1.1 m in front of the listener by azimuthal angles of ±30° in a sound-treated room. The sound image moved from the central position to the left or to the right, or in the opposite direction along 24.2° arc. An adaptive psychoacoustic procedure was used in a diapason of sound images durations from 0.1 to 1.5 s with 0.1s step. All subjects with normal hearing (N = 11) had the minimal time of 0.1 s or lower. Patients demonstrated significantly higher minimal time: 0.4, 0.5 and 0.9 s in case of mild (N = 16), moderate (N = 16) and moderately severe (N = 12) SNHL, respectively (p < 0.001, p < 0.000 1, and p < 0.000 01, Mann-Whitney U Test). Patients were divided into groups in accordance with the WHO classification. Minimal times in patients with mild and moderate SNHL did not differ (p = 0.18, Mann-Whitney U Test), but both were lower than in patients with moderately severe SNHL (p < 0.01, Mann-Whitney U Test). [This work was supported by means of the State assignment (АААА-А18-118013090245-6).]
Phononic crystals as a platform for experimental physics: The direct observation of Klein tunneling
Authors: Shi Chengzhi , Jiang Xue , Li Zhenglu , Wang Siqi , Wang Yuan , Yang Sui , Louie Steven G. , Zhang Xiang
Published: June 2021

Phononic crystals consist of periodic Mie scatterers that modulate the band structure through multi-scattering to control acoustic wave propagation. Recently, the Dirac cone dispersion of phononic crystals with triangular or hexagonal lattices has been used to demonstrate interesting physics such as topologically protected edge states and Zitterbewegung effects. In this work, we present phononic crystals with triangular lattices that can be used as a platform to directly observe Klein tunneling. Klein tunneling is an important quantum mechanical physics proposed in 1929 for high-energy electrons. Klein suggested that electrons that are accelerated to the relativistic regime will tunnel through potential barriers with 100% probability regardless the width and height of the potential barrier. However, Klein tunneling has never been directly observed in quantum mechanics and solid state physics due to the difficulties in satisfying the stringent requirements. Here, we designed phononic crystals with Dirac cone dispersion at which the phonons behave as quasi-particles in the relativistic regime. Near total transmissions of the phonons through potential barriers were measured that are independent from the width and height of the potential barrier. Our results provide the first direct observation of Klein tunneling. This work will inspire a new type of applications that uses phononic crystals as a platform for the experimental studies of wave mechanics and quantum physics.
Analysis of the interaction of Helmholtz resonators in periodic acoustic metamaterials depending on its orientation with the acoustic source
Authors: Solana David R. , Castiñeira-Ibáñez Sergio , Redondo Javier , Bravo-Plana-Sala Jose María , Picó Rubén , Sánchez-Pérez Juan Vicente
Published: June 2021

Acoustic screens based on sonic crystals constitute one of the most promising technological bets of recent years in the field of environmental acoustics. Sonic crystals are defined as new materials formed by arrays of acoustic scatterers embedded in air. The design of these screens is made using powerful simulation models that provide reliable results without the need of expensive experimental testing. This project applies the finite elements method in order to analyse an acoustic barrier that includes (Helmholtz) resonators in its scatterers, and studies the interference of the sonic crystal with the effect of the Helmholtz resonator, depending on its orientation with the acoustic source.
Imaging through an imperfect skull with non-Hermitian complementary acoustic metamaterials
Authors: Craig Steven R. , Welch Phoebe , Shi Chengzhi
Published: June 2021

Biomedical ultrasound is a proficient tool for diagnostic imaging and a wide variety of non-invasive medical procedures due to its high spatial resolution and biocompatibility. While high frequency ultrasound is highly sought after for use in the brain, the skull acts as a highly mismatched and lossy impedance barrier that scatters and damps the energy delivered to a targeted region. This limits the usefulness of ultrasound for brain imaging and brain therapies. Non-Hermitian complementary metamaterials (NHCMM) use transformation acoustics to overcome the impedance mismatch and intrinsic loss of the skull to enable bidirectional acoustic transmission into the brain. Here, we apply the NHCMM to skulls with curved geometries, varying thicknesses, and irregularities to evaluate the performance of NHCMMs in near realistic circumstances. We customize the metamaterial shape for each unique skull geometry to maximize the bidirectional transmission through the skull to better identify internal acoustic scatters. The NHCMM manages to preserve the imaging information of an acoustic tumor embedded in the brain with multiple imperfections present. The evaluation of NHCMMs for skulls with imperfections is vital to gauge its effectiveness for real-world applications as the proposed NHCMM establishes a noninvasive technique for ultrasonic brain imaging through skull and ultrasound diagnostics for neurological disorders.
Transformation acoustics for beamforming in anisotropic media
Authors: Craig Steven R. , Lee Jeonghun , Shi Chengzhi
Published: June 2021

Acoustic wave propagation in anisotropic media like tissue and other biomaterials is important for biomedical acoustics, as ultrasound is commonly used as a technique for non-invasive surgeries and diagnostic imaging purposes. These ultrasound applications require beamformed signals to target specific regions of the body. However, the anisotropic properties of the body (e.g., muscle fibers) distort the beamformed wavefronts, detrimental to the performance of ultrasound therapies and imaging. Here, we propose and experimentally demonstrate a unique transformation acoustic technique that corrects the anisotropic distortive effects to beamform an arbitrarily desired propagation pattern. The experimental measurements demonstrate the effectiveness of this transformation acoustic correction for arbitrary focusing and selfbending beams. Our work provides an important method to suppress undesired anisotropic effects on beamformed waves, to improve upon the precision and effectiveness of medical treatments and diagnostics facilitated by noninvasive ultrasound therapies and imaging.
Reflective acoustic metamaterial for dynamic axial sub-wavelength field control in acoustic levitation
Authors: Koroyasu Yusuke , Tagami Daichi , Hoshi Takayuki , Nagatani Yoshiki , Yoichi Ochiai , Fushimi Tatsuki
Published: June 2021

Acoustic levitation is a non-contact manipulation techniques used in a wide range of fields from biology, physics to medical research. The manipulation of levitated objects can be achieved by controlling the phase of each transducer in a phased array or by using reflective metamaterial. Reflective metamaterial is the acoustic analogy of spatial light modulators, and horizontal movement of the levitated object may be achieved by physical translation of the metamaterial itself. However, axial movement relative to the reflective metamaterial has not been enabled. Here, we propose a reflective metamaterial for dynamic sub-wavelength field control to realize the axial movement of the levitated object, using the property that levitation points are created at distances multiple of half of a wavelength relative to the reflector in a sound field with sufficient sound pressure. It was shown that by mounting the triangular prisms with multiple of half of a wavelength on a reflector and moving them horizontally, the object would rise/fall by the height of the prism. The simple design of reflectors using the properties of acoustic levitation, paves the way to expand the capability of reflective acoustic metamaterial. [Funded by Strategic Research Platform towards Digital Nature Powered by Pixie Dust Technologies, Inc.]
Remote collection of speech recognition data: Considerations for testing children
Authors: Leibold Lori , Porter Heather , Lalonde Kaylah , Merchant Gabrielle R. , Miller Margaret K. , Buss Emily
Published: June 2021

This talk will provide an overview of the methods and lessons learned over the course of three studies in which children’s masked speech recognition performance was assessed remotely. The first study evaluated the binaural intelligibility level difference in typically developing children using families’ personal computers and headphones. The second study examined the impact of face coverings on consonant identification in noise with and without access to visual cues. Participants were children with and without hearing loss. The third experiment evaluated the feasibility of remote speech recognition testing for children with Down syndrome. The latter two experiments entailed providing families with laboratory hardware, following appropriate social distancing and infection control measures. Findings from all three studies will be discussed, highlighting comparisons with data obtained in the laboratory. Recommendations for remote studies involving children will be provided, based on our experiences and the resultant data.
Effect of voice problems on vowel identifications in different acoustics environments
Authors: Bottalico Pasquale , Murgia Silvia , Ishikawa Keiko
Published: June 2021

Voice disorders can reduce speech intelligibility. This study evaluated the effect of noise, voice disorders, and room acoustics on vowel intelligibility. College students listened to 9 vowels in /h/-V-/d/ format. The speech was recorded by three adult females with dysphonia and three adult females with normal voice quality. The recordings were convolved with three oral-binaural impulse responses with 0.4 s, 0.7 s, and 3.1 s of reverberation time. The test was performed online. The intelligibility and the listening easiness were significantly higher when the speakers had normal voice quality and in low reverberated environments.
Source detection and localization in the ocean with a Bayesian approach
Authors: Michalopoulou Zoi-Heleni , Pole Andrew , Abdi Ali
Published: June 2021

Source localization and detection of sound sources in the ocean are investigated from a Bayesian Matched Field Processing perspective. Unknown parameters comprise the source spectrum along with source location; the spectrum is estimated within the localization and detection process. We develop incoherent and coherent processors, integrating the source spectrum estimation employing a Gibbs sampler. Using synthetic data we find that the coherent processor is superior to the incoherent processor and the standard Matched Field approach both in terms of source location estimates and uncertainty. The coherent and incoherent techniques are also applied to real data from the Hudson Canyon experiment with the same conclusion. Employing Receiver Operating Characteristic (ROC) curves, the coherent and incoherent processors are evaluated and compared in the task of joint detection and localization as well. The coherent detector/localization processor is superior to the incoherent one. Joint detection and localization performance is evaluated with Localization-ROC curves. [Work supported by ONR.]
Unsupervised learning for seabed type and source parameters from surface ship spectrograms
Authors: Neilsen Tracianne B. , Tsai Zhi-Hao , Hodgkiss William , Knobles David P.
Published: June 2021

Lack of labeled field data in ocean acoustics is a limitation for applying supervised machine learning techniques. Unsupervised techniques have shown potential for classifying signals, but questions remain as to how much additional information unsupervised techniques can learn from ocean acoustic data. This paper evaluates the ability of an unsupervised k-mean clustering algorithm to provide information about the seabed and location of a moving source. The training data are synthetic spectrograms from surface ships based on a wide variety of ship speeds, closest distance to the hydrophone, and seabed types. The resulting clusters are evaluated to discover trends into which types of spectrograms are in each cluster, and the characteristics of the cluster centroids are investigated. These studies highlight the speed-distance ambiguity seen in ship spectrograms as well as the ambiguity between distance and bottom loss of the seabed. The trained algorithm is tested on both synthetic spectrograms and ones from merchant and cargo ships recorded during the Seabed Characterization Experiment in 2017. The future of unsupervised machine learning in ocean acoustics depends on correctly interpreting the results and testing the ability of trained networks to generalize.
Matched field source localization with Gaussian processes
Authors: Michalopoulou Zoi-Heleni , Gerstoft Peter , Caviedes-Nozal Diego
Published: June 2021

For a sparsely observed acoustic field, Gaussian processes can predict a densely sampled field on the array. The prediction quality depends on the choice of a kernel and a set of hyperparameters. Gaussian processes are applied to source localization in the ocean in combination with matched-field processing. Compared to conventional processing, the denser sampling of the predicted field across the array reduces the ambiguity function sidelobes. As the noise level increases, the Gaussian process–based processor has a distinctly higher probability of correct localization than conventional processing, due to both denoising and denser field prediction.
Geoacoustic inversion of modal dispersion on the New England Mud Patch. I: Experimental quantification of information content in higher-order modes
Authors: Bonnel Julien , Dosso Stan , Wilson Preston S. , Knobles David P.
Published: June 2021

This paper presents the results from a geoacoustic inversion study performed using a combustive sound source signal recorded on a vertical line array during the 2017 Seabed Characterization Experiment (SBCEX17). A single receiver modal estimation method (source deconvolution and warping) is recursively applied along the array channels to estimate modal time-frequency dispersion, resulting in modal dispersion data for 18 modes between modes 1 and 21. These data are then used as an input for trans-dimensional Bayesian geoacoustic inversion. The paper compares inversion results obtained with subsets of modes (1 to 7 and 1 to 15) to those obtained with the whole set (modes 1 to 21) to explore the data information content associated with high-order modes. The study shows that high-order modes enable the resolution of fine details in the seabed sound-speed profile, such as a small sound speed increase over the first 8 m of the seabed (i.e., within the upper portion of the so-called “mud layer,” an important feature of the experiment area). [Work supported by the Office of Naval Research.]
Local oceanographic conditions link predator-prey dynamics from surface waters to the deep ocean
Authors: Baumann-Pickering Simone , Širović Ana , Trickey Jenny S. , Rice Ally , Lankhorst Matthias , Send Uwe , Renfree Josiah S. , Demer David A.
Published: June 2021

Offshore pelagic environments are dynamic and rich in biodiversity, yet our understanding of these habitats is lacking as they are surveyed less frequently than coastal areas. We present results from one-year (October 2016i–October 2017) of comprehensive oceanographic mooring measures from a site located 150 nmi offshore Southern California in abyssopelagic waters, spanning water mass, nutrient, primary productivity, fish, and cetacean variables. We identified abrupt changes in water properties, bringing distinct biological communities to our site. Some examples were active acoustically observed backscatter from diel vertical migrators, present during parts of summer and throughout fall, coincided with passive acoustically measured night-time echolocation of common dolphins (Delphinus delphis). Risso’s (Grampus griseus) and Pacific white-sided dolphin (Lagenorhynchus obliquidens) echolocation was also coincident with near-surface backscatter but during winter and early spring. Backscatter during that time was predominantly from small pelagic fishes, as diel vertical migration was virtually absent. Echolocation from Cuvier’s beaked whales was prominent during winter and spring, associated with colder water from the California Current, but were absent in early summer when the water in the deep sea abruptly warmed. This study demonstrates how local oceanographic conditions link predator-prey dynamics from surface waters to the deep sea.
Gauss-Markov model for scattering of acoustic signals from rough surfaces
Authors: Goldman Geoffrey H
Published: June 2021

Simple models are used to characterize the acoustic signal reflected by the ground and received by an array of microphones for elevated sources in the farfield.
The control of quadcopter propeller radiated noise
Authors: Brungart Timothy A. , Olson Stephen T. , Kline Brian L. , Yoas Zachary W.
Published: June 2021

Simple scaling analysis is used to show that significant reductions in quadcopter propeller radiated noise can be achieved, at the hover condition, by reducing the quadcopter and/or payload weight to, in turn, reduce the propeller tip speed. The scaling analysis shows that the propeller radiated noise, at the hover condition, scales as the cube of the combined quadcopter and payload weight. The reductions in radiated noise predicted from the scaling analysis are verified experimentally with quadcopter propellers in an anechoic chamber. Experiments also show that reducing the propeller tip speed by increasing the propeller blade pitch or blade number, while maintaining a given static thrust, is ineffective at reducing the radiated noise. In fact, it is shown that too high a blade pitch and/or blade number can significantly increase propeller radiated noise even though the blade tip speed is significantly reduced. This is attributed to increased propeller blade and blade wake interactions for the increased blade pitch and number.
Aeroacoustics damping performances of double-layer perforated pipes at low grazing-bias flow Mach number
Authors: Zhao Dan , Gay YX
Published: June 2021

The present work studies the aeroacoustics damping characteristics of double-layer perforated pipes (DPP) at low grazing-bias flow Mach number. The noise damping mechanism involved with thermos-viscous and vortex shedding, through which acoustical energy is somehow absorbed by a few tiny circle-shaped orifices perforated on the cylindrical pipes. Here, Δb (sound absorption coefficient) is used as a noise damping measure. It characterizes the fraction of incident sound energy being attenuated. DPP are associated with a bias flow passing through each orifice and a grazing flow. It is another flow stream grazing the inner surface of the inner perforated pipe. The grazing flow velocity is denoted by Mach number Mg. Since the DPP have different porosities δi and δo, we use Mb to denote the bias flow Mach number at the outlet of the cooling flow pump. Experimental evaluations on Δa are performed on five double-layer perforated pipes over the Strouhal number range of 0.25 ≤ St ≤ 1.2. It is shown that increasing the grazing flow Mg gives rise to deteriorated overall acoustic damping performances over the measured St range. However, it is found that acoustic damping is improved, i.e., Δa is increase with the implementation configuration of δi > δo.
Numerical investigation of a Y-shaped thermoacoustic combustor with a Helmholtz resonator implemented and operated at off-design conditions
Authors: Zhao Dan
Published: June 2021

Self-excited thermoacousitc instability is undesirable in propulsion and gas turbine engines. To attenuate these instabilities, Helmholtz resonators shaped like a beer bottle are typically applied to dampen combustion-driven acoustic oscillations. The damping effect is maximized at resonance, since large volume of fluid in the cavity volume compresses and expands periodically, while a mass of the fluid in the resonator neck oscillates. Such periodic motions lead to thermos-viscous and vortex shedding losses. In this work, two-dimensional numerical studies on a Y-shaped thermoacoustic combustor with a Helmholtz resonator attached are conducted to shed lights on the damping performances of the resonators at off-resonance conditions. The Y-shaped system has a mother stem at the bottom. It splits into 2 bifurcating upper branches with different lengths corresponding to 2 non-harmonic longitudinal modes. Premixed propane and air are burnt in the bottom stem. The effects of the off-design conditions achieved by varying the resonator cavity volume on the limit cycle oscillations and the combustion products are examined in details. It is found that when the mass flow rate oscillation amplitude at the neck is increased by 1500%, the acoustic pressure amplitude is reduced by 20%. However, the dominant and secondary mode frequencies are almost unchanged.
Development of multimode and spiral wave acoustic transducers: Yesterday, today, and tomorrow
Authors: Brown David A.
Published: June 2021

This presentation reviews the early development of multimode transducers in both U.S. and Russia and their use in DIFAR sonobuoys and other directional receivers. This lead the way for today’s development of the spiral wave transducer that creates outward diverging acoustic waves from a single transducer, whose wavefront (surface of constant phase) is a continuous outgoing spiral surface created by the superposition of orthogonal dipoles driven in phase-quadrature. Spiral waves hold promise for tomorrow’s underwater acoustic navigation beacons in GPS-denied access areas and for broader bandwidth underwater communications.
Using browser-based software to teach acoustic theory of speech production
Authors: Neel Amy T.
Published: June 2021

I will demonstrate how I use browser-based software authored by Mark Huckvale to promote active learning of the acoustic theory of speech production. Students create the complex glottal tone using ESynth, filter the glottal tone with various vocal tract filters with ESystem, explore the impact of vocal tract shapes on formants using VTDemo, and examine their own vowel formants with ESection.
Velocity estimation via Doppler signal processing: An educational experiment
Authors: Singer Jonah , Oelze Eden
Published: June 2021

In a previous talk, we presented the use of Doppler processing of an acoustic signal recorded from a moving RC car to estimate the speed of the RC car traveling to and away from an observer. In this work, a multi-harmonic dynamic model for the RC car motor is incorporated into the acoustic model and this multi-harmonic tracking algorithm is used to estimate the velocity of the RC car based on this improved model, implemented in Python.
Gold Medal 2021: James F. Lynch
Authors: Lynch James F.
Published: June 2021

The Gold Medal is presented in the spring to a member of the Society, without age limitation, for contributions to acoustics. The first Gold Medal was presented in 1954 on the occasion of the Society's Twenty-Fifth Anniversary Celebration and biennially until 1981. It is now an annual award.
“It’s Not Particularly P.C., You Know . . .”: Women Coaches’ Performing Gender in Strength and Conditioning
Authors: Thomas Gavin , Guinan Jaime , Molnár Győző
Published: June 2021

Strength and conditioning (S&C) has become a chief part of athletes’ physiological preparation. Despite S&C’s growing presence across sports, women coaches have been generally marginalized and underrepresented. This study explores female S&C coaches’ experiences and coping mechanisms in a male-dominated industry. Semi-structured interviews with 15 female S&C coaches were conducted. The main themes identified from interview data are organizational politics, impression management, and humor. The findings suggest that women S&C coaches are often in subservient positions and have to adopt some traditional, male-generated subcultural practices to fit in. They carefully manage their coaching front stage to generate an impression that is expected and accepted in the given milieu. In their efforts to fit in, women often find themselves in a multiplicity of power matrices that involve a continuous negotiation of gender identity, internal politics, and sexist banter.
Comment on “Individual heterozygosity predicts translocation success in threatened desert tortoises”
Authors: Hedrick Philip W.
Published: June 2021

Scott
et al
. (Reports, 27 November 2020, p. 1086) suggest, on the basis of conclusions obtained from a desert tortoise reintroduction program, that higher genomic heterozygosity should be used to identify individuals for successful translocation. I contend that this recommendation is questionable given these relocated tortoises’ unknown origin, their high mortality, insufficient data on resident tortoises and other components of fitness, and potential allelic dropout.
Rewriting the genetic code
Authors: Jewel Delilah , Chatterjee Abhishek
Published: June 2021

Making room in the genetic code allows the creation of designer proteins with new building blocks
Actinobacillus actinomycetemcomitans
in Human Periodontal Disease: a Cross-Sectional Microbiological Investigation
Authors: Slots Jørgen , Reynolds Homer S. , Genco Robert J.
Published: June 2021

Actinobacillus actinomycetemcomitans
is a facultative gram-negative bacterium which has been associated with severe oral and nonoral infections. This study examined its occurrence in the oral cavities of 10 normal juveniles, 11 normal adults, 10 juvenile periodontitis patients, and 12 adult periodontitis patients. Four deep periodontal pockets and two normal periodontal sites were sampled in the diseased patients, and six normal periodontal sites were sampled in the healthy individuals. In all subjects samples were obtained from the cheek, tongue, and saliva. Samples from a total of 172 normal periodontal sites, 83 deep periodontal pockets, 42 cheek mucosae, 42 tongue dorsa, and 42 salivas were examined. Isolation was performed by using a medium for selective isolation of
A. actinomycetemcomitans
(Trypticase soy agar [BBL Microbiology Systems] supplemented with 10% serum and 75 μg of bacitracin per ml). The carrier rates were 20% for normal juveniles, 36% for normal adults, 50% for adult periodontitis patients, and 90% for juvenile periodontitis patients.
A. actinomycetemcomitans
was on average recovered in about fivefold-higher numbers from infected deep periodontal pockets than from infected normal subgingival areas. Samples of periodontal pockets generally contained 100-fold-more cells of
A. actinomycetemcomitans
than did samples of the cheek, tongue, and saliva.
A. actinomycetemcomitans
is commonly isolated from patients with juvenile periodontitis, often isolated from patients with adult periodontitis, and occasionally isolated from normal juveniles and adults. Its primary oral ecological niche appears to be dental plaque and periodontal pockets.
Sensitive solid-phase radioimmunoassay for detection of human immunoglobulin G antibodies to varicella-zoster virus
Authors: Friedman M G , Leventon-Kriss S , Sarov I
Published: June 2021

A sensitive solid-phase radioimmunoassay for detection of antibodies to varicella-zoster virus (VZV) is described. The antigen consisted of a sonically disrupted extract of VZV-infected human embryo cells. 125I-labeled rabbit anti-human immunoglobulin G (IgG) specific for the Fc portion of human IgG was used to detect human IgG bound to viral antigen. With this technique, 193 human sera were evaluated for their IgG antibody titer against ZVZ. Subjects included 62 healthy adults, 33 young children (12 healthy), and 49 patients. Titers obtained by the radioimmunoassay were compared with those obtained by indirect fluoresence antibody staining of membrane antigen. The radioimmunoassay technique described gave titers approximately 5 X 10(4) times higher than those shown by indirect fluorescence. It can be used for routine diagnosis, but is especially suited to determining immune status to VZV, as defined by presence or absence of antibodies to the virus; for epidemiological studies; or for determining patients at risk who are exposed to the virus. No heterotypic titer rises to VZV were observed in sera with fourfold or greater rises to Epstein-Barr virus or cytomegalovirus. Sera of eight subjects with fourfold or greater titer rises to herpes simplex virus reacted in various ways: in six cases no significant change occurred in titer to VZV; one had a significant decrease in titer by the radioimmunoassay; and one had a significant increase. Possible reasons for these titer changes are discussed.
Influenza viruses in birds: rapid identification by counterimmunoelectrophoresis
Authors: Lecomte J , Berthiaume L , Boudreault A
Published: June 2021

Counterimmunoelectrophoresis with an antiserum raised in rabbits against the M protein of the avian N virus proved to be particularly useful for large-scale identification of influenza A virus isolates. Of a total of 231 hemagglutinating agents isolated from 1,656 rectal swabs collected from shore and open-country birds, 158 could be identified as influenza A viruses by counterimmunoelectrophoresis, and 75 were serologically related to Newcastle disease virus by hemagglutination inhibition with an antiserum to Newcastle disease virus. Two isolates contained a mixture of influenza A virus and Newcastle disease virus; although the Newcastle disease virus virus particles outnumbered the influenza A virus particles in a ratio of 1,000:1, as seen by electron microscopy, the latter could be readily detected by counterimmunoelectrophoresis. This type of assay appears to be of potential use for epidemiological surveillance of influenza virus isolated from humans and animals. It combines specificity, sensitivity, and simplicity.
Improved reliability of the primary plate bacitracin test on throat cultures with sulfamethoxazole-trimethoprim blood agar plates
Authors: Kurzynski T , Meise C , Daggs R , Helstad A
Published: June 2021

The primary plate bacitracin differentiation disk susceptibility test identified 85% of group A streptococci from throat cultures on SXT-BA(CO2) plates within 24 h, as compared to only 26% on a conventional sheep blood agar plate.
Feline leukemia virus: survival under home and laboratory conditions
Authors: Francis D P , Essex M , Gayzagian D
Published: June 2021

Feline leukemia virus maintained its infectiousness in cell culture medium at 37 degrees C or lower for at least 48 h. However, virus in saliva or medium was inactivated within a few hours if allowed to dry.
Problems affecting performance of the fluorescent treponemal antibody-absorption test for syphilis
Authors: Hunter E F , Adams M R , Orrison L H , Pender B J , Larsen S A
Published: June 2021

Immunofluorescent staining of Treponema pallidum was studied to clarify the effect of three factors on the results of the fluorescent treponemal antibody-absorption test: (i) heat inactivation of sera at 56 degrees C for 30 min before testing, (ii) use of multicircle slides, and (iii) tungsten illumination to visualize and assess unstained treponemes on reactive as well as nonreactive smears. It was found that serum inactivation before testing was not necessary for detection of immunoglobin G antibody, but an immunoglobulin M prozone was detected in unheated serum. On multicircle slides, it was demonstrated that a false-positive reaction could be obtained in 30 s at 37 and 25 degrees C if a smear where a nonreactive serum had been placed was crossed by a strongly reactive serum from another circle. Tungsten illumination proved necessary for correct assessment of unstained treponemes on all fluorescent treponemal antibody-aborption test smears, reactive or nonreactive. The possible role of these factors in incorrect fluorescent treponemal antibody-absorption test results is discussed.
Evaluation of colistin and nalidixic acid in Todd-Hewitt broth for selective isolation of group B streptocci
Authors: Fenton L J , Harper M H
Published: June 2021

Todd-Hewitt broth (THB) containing colistin and nalidixic acid was compared with four other media with respect to efficacy of isolation of group B streptocci. It was effective as plain THB, THB with gentamicin and nalidixic acid and blood, and THB with colistin, nalidixic acid, and blood. THB with gentamicin and nalidixic acid, but without blood, was inhibitory to group B streptocci. The value of THB with colistin and nalidixic acid lies in its ability to successfully inhibit gram-negative organisms and still promote group B streptococcal growth without the addition of blood. This greatly reduces the time and expense of media preparation and permits early determination of bacterial growth, so that other means of rapidly identifying group B streptocci can be applied at the earliest possible time.
Serotypes of Neisseria meningitidis isolated from patients in Norway during the first six months of 1978
Authors: Holten E
Published: June 2021

During the first 6 months of 1978, 114 strains of Neisseria meningitidis isolated from patients in Norway were serotyped. Among 27 group C strains, type 2 was most common, whereas 82% of the 82 group B isolates did not react with antisera to the standard serotypes 1 to 12. These strains were shown to belong to a new serotype, type 15. Also some group A and C strains had the type 15 antigen. Investigations on a possible immunoprophylaxis against group B meningococcal disease in Norway should accordingly proceed with type 15 rather than with type 2 meningococci.
Salient features of Haemophilus vaginalis
Authors: Greenwood J R , Pickett M J
Published: June 2021

A total of 78 strains of Haemophilus vaginalis were examined for 104 features. All strains fermented dextrin, maltose, and starch. Additionally, more than 90% of the strains fermented galactose, glucose, and ribose. Arbutin, cellobiose, melibiose, rhamnose, and salicin were not fermented by any of these strains. None of the strains acidified any of 14 alcohols or alkalinized any of 25 organic salts and amides. More than 90% of the strains hemolyzed human blood agar and hydrolyzed hippurate. No strain hemolyzed sheep blood agar. A recommendation is included for those minimal features that best differentiate H. vaginalis from other oxidase- and catalase-negative, gram-negative organisms.
Reproducibility of an Indirect Immunofluorescent-Antibody Technique for Capsular Serotyping of
Klebsiella pneumoniae
Authors: Murcia Alejandro , Rubin Sally Jo
Published: June 2021

Reproducibility of capsular serotypes of 55 consecutive clinical isolates of
Klebsiella pneumoniae
was evaluated by an indirect immunofluorescent-antibody technique previously described by Riser et al. (J. Clin. Pathol.
29:
296-304, 1976) Five colonies per specimen were examined for colony-to-colony variation, day-to-day variation, and reader-to-reader variation. Seventy-two reference strains were tested with each of 18 pools and 72 specific antisera prior to the clinical specimens to determine antiserum specificity and cross-reaction patterns. Lot-to-lot variation was examined with the reference strains. There was minimal lot-to-lot variation among the antisera tested. Ten antiserum pools required supplementation with individual antisera. The patterns of supplementation may vary from lot to lot. Colony-to-colony variation in intensity of immunofluorescence occurred, but there was no variation in serotype. These findings differ from previously reported colonial variation which occurred when API 20E biotypes were determined for individual colonies of
K. pneumoniae
directly from clinical specimens. Eighteen percent of clinical isolates studied gave cross-reactions when tested with the indicated specific antiserum. All but one of the cross-reactions were resolved with further dilutions. Day-to-day and reader-to-reader variations were minimal. The immunofluorescent-antibody technique is a reliable and reproducible method for capsular serotype determination. Capsular serotypes are less variable than API biotypes since colony-to-colony variation of serotype does not occur.
Enterotoxin production by Staphylococcus aureus strains isolated from cases of chronic osteomyelitis
Authors: Sourek J , Výmola F , Trojanová M , Zelenková L , Matějovska V , Bergdoll M S
Published: June 2021

Of 264 Staphylococcus aureus strains selected at random from 3,978 strains isolated from chronic osteomyelitis patients, 79 were found to produce enterotoxin. A majority of the strains (65%) were nontypable by phages belonging to the international phage set for human strain typing. The significance of these strains and their circulation among the population is discussed, especially from the standpoint of their possible role in the development of osteomyelitis.
Standardization of direct susceptibility test for blood cultures
Authors: Fay D , Oldfather J E
Published: June 2021

Insufficient data are available to establish the reliability of direct disk diffusion susceptibility tests performed utilizing positive blood culture broth as inoculum. When Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853 were used, 0.03 ml of turbid overnight blood culture broth was found to produce zone diameters closely approximating the size of diameters obtained by a standardized method. Results of direct (0.03 ml of inoculum) and standardized susceptibility tests were then compared for 116 positive blood cultures (1,069 individual disk comparisons). There were 1,011 test agreements (94.6%). There were also 48 (4.5%) minor discrepancies (change between sensitive and intermediate or between intermediate and resistant) and 10 (0.9%) major discrepancies (change between sensitive and resistant). The major discrepancies were randomly distributed among several organisms and antibiotics. Discrepancies occurred most frequently in the more clinically acceptable direction; i.e., in 79.3% the direct test indicted greater resistance than the standardized test. These data establish that 0.03 ml of turbid overnight blood culture broth produces results which compare closely to those obtained with standard methods, and in practice yield direct susceptibility results with a clinically acceptable level of reliability.
Evaluation of two transport systems for gonorrhea cultures
Authors: Dowda H , Nelson C F
Published: June 2021

The ability of the Transgrow and JEMBEC systems to yield positive cultures when transported to a central laboratory was compared. There were no significant differences in the recovery rates of the two systems. Statistically significant decreases in recovery rate were noted when each system was compared with the traditional plate-candle jar technique.
Enhancement of antigen incorporation and infectivity of cell cultures by human rotavirus
Authors: Schoub B D , Kalica A R , Greenberg H B , Bertran D M , Sereno M M , Wyatt R G , Chanock R M , Kapikian A Z
Published: June 2021

Infection of cell cultures with human rotavirus preparations was attempted and the effects of trypsin and low-speed centrifugation on antigen incorporation, as demonstrated by immunofluorescence and radioimmunoassay, were determined. In addition, the effect of viral aggregation on antigen incorporation was investigated by filtering viral preparations. Four strains of human rotavirus were employed, and the results were compared to those obtained with two tissue culture-adapted animal rotaviruses. Centrifugation and trypsin appeared to have little or no effect on infectivity of the tissue culture-adapted (simian rotavirus) or -adaptable (Nebraska calf diarrhea virus) strains, whereas centrifugation and viral aggregation appeared to be essential for the human viruses. In addition, trypsin enhanced antigen incorporation of the human strains to some extent. Infectivity for cell cultures and in vitro human rotavirus protein formation was demonstrated by [35S]methionine incorporation, and the specificity of this human viral protein was established by radio-immunoprecipitation.
Practical method to facilitate estimation of Streptococcus mutans levels in saliva
Authors: Köhler B , Bratthall D
Published: June 2021

A method was developed to facilitate the estimation of Streptococcus mutans levels in saliva. Saliva-contaminated wodden spatulas were pressed directly against an elevated agar plate containing a selective medium. The results were compared with the number of S. mutans per 1 ml of paraffin-stimulated saliva. It was shown that the spatula method gave a good estimation of the level of S. mutans infection. The incubation was also made in expired air instead of 95% N2-5% CO2. The outgrowth was in good agreement with that after conventional incubation. The method is useful in epidemiological studies or in selecting persons at a high caries risk, and when ordinary saliva sampling cannot be done, for example in small children. Compared with conventional saliva sampling, this method requires less time and material at sampling as well as at the laboratory.
Rickettsial hemolysis: rapid method for enumeration of metabolically active typhus rickettsiae
Authors: Walker T S , Winkler H H
Published: June 2021

A new assay is described for enumerating biologically active typhus rickettsiae (Madrid E strain), based on adsorption of rickettsiae to erythrocytes in the presence of NaF (which allows adsorption but not lysis) and lysis in the presence of anti-Rickettsia prowazeki immune serum (which allows only a single round of lysis). The number of lysed erythrocytes is then used to estimate the number of active rickettsiae.