bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance and measurement of a bistable acoustic valve for earphones
Authors: Monti Christopher , King Charles , Jones Christopher , Miller Thomas , Albahri Shehab , Salazar Jose , Mohammadi Mohammad
Published: June 2021

Hearing devices often employ ear seals to optimize playback quality and reduce the leakage of low frequency signals. There are several downsides to having a fully blocked ear. One negative effect is the inability of the user to hear external sounds. Another downside of an ear seal is the introduction of occlusion effects, such as the amplification of the user's own voice. The ideal hearing device would have excellent sound reproduction but also avoid the negative effects of a sealed ear. One way to accomplish this goal is to have an earphone that can change states between being sealed and being open through a vent. An acoustic valve can be selectively opened and closed to change the state. Unlike active occlusion reduction and active pass through algorithms, a bistable valve will only consume power whentransitioning between the open and closed states. In this talk, we present the important characteristics of an acoustic valve for battery-powered hearing devices. We explore the design and performance of one example acoustic valve. We discuss how to measure the acoustic performance of the valve and how the valve performs in real-world earphones. Practical considerations for in-ear valves are also examined.
Anomalous low frequencies in the Japanese koto
Authors: Coaldrake A. K.
Published: June 2021

A finite element model based on a computed tomography (CT) scan of the Japanese koto, a 13-string plucked zither, was previously found to predict frequencies accurately above 100 Hz when compared to a range of physical experiments with the original instrument. Predictions for frequencies below 100 Hz were more ambiguous. Anomalous low frequency components, also known as phantom partials, have been observed in other zithers, notably the piano. The objective of this study was to assign meaning to all frequencies in general, but specifically as reported in this paper, to frequencies below 100 Hz. The results of the analysis using the CT model as an investigative tool in conjunction with the physical experiments results, identified three types of low frequencies in the sound spectra: (1) Frequencies which are air mediated frequencies and those which are wood mediated; (2) The different frequencies associated with instrument’s wood grain orientation in the x-, y- and z-direction; and (3) Beating arising from the periodic interaction of two frequencies to produce a difference spectrum. These results help to expand the knowledge of the complex resonances in the koto’s characteristic sound.
Exploring visualization techniques to enhance and inform soundscape analysis
Authors: Smith Michael J. , Kates Varghese Hilary S. , Lurton Xavier , Mayer Larry A. , Miksis-Olds Jennifer
Published: June 2021

Anthropogenic impact on soundscape dynamics is complex and often highly specific to the environment under investigation. As a result, rigorous qualitative and quantitative analyses are required to contextualize temporal, spatial, and spectral changes. As part of a multidisciplinary effort to study the acoustic characteristics of a deep-water multibeam echosounder and its impact on the local soundscape, continuous acoustic recordings were collected from an array of 89 seafloor mounted hydrophones off the coast of San Clemente, California during multibeam surveys in the area from January 4–8, 2017 and January 3–6, 2019. These datasets were used to calculate soundscape metrics including sound pressure level, sound exposure level, and decidecade band levels covering [50 Hz–48 kHz]. The remarkable density and resolution of these multi-receiver datasets posed significant and specific processing and display challenges with respect to understanding the micro- and macro-changes within the soundscape. This work presents several visualization approaches designed to exploit strong human visual perceptions skills to better understand changes in soundscape metrics, and to help quickly identify spatial/temporal periods for further quantitative analysis. Visualizations tracking the evolution of soundscape metrics through time, space, and frequency are presented here, illustrating their utility towards soundscape analysis.
Protecting sleep from noise in the built environment
Authors: Solet Jo M.
Published: June 2021

Recognition is growing over the need to protect patrons from hearing damage caused by high sound levels in stadiums and concert halls. In parallel, attention must be drawn to the health and safety impacts of lower level sound exposures, which may produce resident sleep loss in built environments: homes, dormitories, hotels, and care facilities. Many localities have ordinances that define day and night sound level maximums as measured at property lines. These ordinances apply to noise nuisance produced on one property and experienced on another. Some are complaint-driven; these do not apply in advance during the review process for acquiring building permits. Those living in poorly built, multiple occupancy buildings may have substantial exposure to noise intrusions, including those produced within their own building envelope. Sleep disruptive noise intrusions are especially common in crowded, under-resourced neighborhoods and contribute to health disparities. To protect sleep, noise ordinances and building codes need to be informed by scientific evidence derived from sleep disruption research. Insufficient sleep is known to have multiple negative consequences, including impaired antibody production. Supporting the immune system through sufficient sleep is especially critical during the COVID crisis, for directly fighting infection, as well as for supporting adequate vaccine response.
Finite element analysis as a tool to design acoustic metamaterials by a non-expert user
Authors: Naify Christina J.
Published: June 2021

Computational tools such as finite element methods are an extremely powerful tool for design of acoustic metamaterials. The ability of these tools to couple multi-physics such as structural mechanics and acoustics within an off the shelf graphical user interface opens the tools to a wide range of users. It is very easy, however, to use these tools without full understanding of the physics involved, which may lead to non-physical results. Additionally, FEM problems can be limited in their ability to handle large problems, such as 3D geometries, or small features on large parts, requiring simplifications on the part of the user. This presentation will review several acoustic metamaterial case studies where finite element methods are used to predict response of multi-physics problems, and compare those computational studies to experimentally measured results. These case studies will be presented from the perspective of a casual user of computational tools, someone who understands the physics of the problem, but may be limited in fully exploiting the capabilities of specific tools. Discussion will focus on areas where user tools and interfaces could be improved, as well as where shortcuts have been taken and the effect of those shortcuts.
Articulatory descriptions: It is all fun and games
Authors: Bent Tessa
Published: June 2021

In the 100-level Phonetics for Speech and Hearing Sciences course at Indiana University, students learn articulatory descriptions for the vowels and consonants of American English. I have incorporated activities to help students practice the descriptions and apply them to real-world problems. The activities include (1) articulatory description puzzles: Students are given a series of consonant and vowel articulatory descriptions. They must then determine the corresponding vowels and consonants, which ultimately make up a quote. (2) Sounds of Fortune: In this “Wheel of Fortune”-style game rather than guessing letters in standard orthography, the answer is in IPA and students make their guesses by using the articulatory description (e.g., “I’d like to buy a high front tense vowel”). (3) Misheard song lyrics: Students are presented with song clips, which are likely to result in errors. The students write down what they hear in orthography. After that, they are presented with the actual lyric. They then phonemically transcribe both the real and misheard lyrics. They identify consonant errors across the two transcriptions and then compare in terms of their place, manner and voicing characteristics. These activities can be used directly after the introduction of the material as well as for review exercises.
Robust North Atlantic right whale detection using deep learning models for denoising
Authors: Vickers William , Milner Ben , Risch Denise , Lee Robert
Published: June 2021

This paper proposes a robust system for detecting North Atlantic right whales by using deep learning methods to denoise noisy recordings. Passive acoustic recordings of right whale vocalisations are subject to noise contamination from many sources, such as shipping and offshore activities. When such data are applied to uncompensated classifiers, accuracy falls substantially. To build robustness into the detection process, two separate approaches that have proved successful for image denoising are considered. Specifically, a denoising convolutional neural network and a denoising autoencoder, each of which is applied to spectrogram representations of the noisy audio signal, are developed. Performance is improved further by matching the classifier training to include the vestigial signal that remains in clean estimates after the denoising process. Evaluations are performed first by adding white, tanker, trawler, and shot noises at signal-to-noise ratios from −10 to +5 dB to clean recordings to simulate noisy conditions. Experiments show that denoising gives substantial improvements to accuracy, particularly when using the vestigial-trained classifier. A final test applies the proposed methods to previously unseen noisy right whale recordings and finds that denoising is able to improve performance over the baseline clean-trained model in this new noise environment.
Undersea detection of aerial targets
Authors: Adams Matthew T. , Bishop Brian , Moore Jesse , Tufariello Justin , Kim Jerry
Published: June 2021

The undersea detection of aerial targets is a difficult acoustic problem that was first examined almost 50 years ago and has received renewed interest lately for several important applications. In this work, the authors are interested in the trade space of feasibility for airborne sources at different altitudes and atmospheric conditions and for undersea receivers subject to different sound speed and bathymetry profiles.
Correlation of deep seabed structure with waveguide invariant
β
in ±∞
regime
Authors: Knobles David P. , Neilsen Tracianne B. , Wilson Preston S.
Published: June 2021

An examination of the received spectrogram levels of merchant ship recordings has identified an important acoustic feature at the very-low frequencies (VLF). The data were recorded on vertical line arrays deployed in the New England Mudpatch during the Seabed Characterization Experiment 2017 in about 75 m of water. The VLF feature occurs when the group velocities of modes 1 and 2 are equal at a frequency f = F. The average value of F from about twenty ship signatures observed in the Mudpatch is about 24.5 Hz. Generally, the observation of this VLF feature is a result of βmn( F) = infinity where βmn is the waveguide invariant for modes n and m. The sign of the waveguide invariant is determined by the sign of the difference between the phase speeds at F. Also, we predict what F would be in two areas south of the Mudpatch, including a second smaller Mudpatch in about 125 m of water and an area near the slope in about 250 m of water where the sediment is reported to be sand over multiple layers of softer sediments. Finally, F is predicted on the Atlantis II seamount with a limestone seabed in about 1650 m of water.
Numerical evaluations of the lossy spatial impulse response for a circular piston in the far field
Authors: A. Drew , McGough Robert J.
Published: June 2021

Numerical evaluations of the lossy spatial impulse response are achieved by substituting Green's functions from the Power Law Wave Equation into the Rayleigh integral. The addition of loss introduces noticeable attenuation, dispersion, and delay into the impulse response, which become more pronounced in the far field.
Numerical investigation on the porosity effect of a bias-flow perforated liner on attenuating self-excited thermoacoustic oscillations
Authors: Guan Di , Zhao Dan
Published: June 2021

Self-excited thermoacoustic oscillations are unwanted in propulsion and stationary gas turbines due to the undesirable structural and heating damage to the engine systems. To prevent overheating and damping noise, perforated liners are widely applied in engines. It is a cylindrical metal sheet perforated with a number of millimetre-size circle orifices. In this work, numerical studies are conducted on an acoustically open-open thermoacoustic combustor with premixed propane and air fuelled and burnt. A perforated liner with a porosity σ is implemented downstream of the combustor in the presence of a cooling flow (also known as bias flow). The effects of (1) the cooling mass flow rate ṁb and (2) the porosity σp are examined one at a time. It is found that in the absence of the cooling flow, i.e., ṁb = 0, the perforated liner’s acoustic damping effect is quite small. Increasing is found to increase the liners damping performance in terms of attenuating the thermoacoustic oscillations, due to the enhanced vortex shedding generated over the rims of the perforated holes. In addition, there is an optimum cooling flow rate corresponding to the maximum acoustic damping effect of the liner. Furthermore, for a given mass flow rate, there is an optimum porosity.
Selective monitoring of noise emitted by vehicles involved in road traffic
Authors: Czyzewski Andrzej
Published: June 2021

An acoustic intensity probe was developed measures the sound intensity in three orthogonal directions, making possible to calculate the azimuth and elevation angles, describing the sound source position. The acoustic sensor is made in the form of a cube with a side of 10 mm, on the inner surfaces of which the digital MEMS microphones are mounted. The algorithm works in two stages. The first stage is based on the analysis of sound intensity signals, and it detects acoustic events. The second stage analyses a detection function based on the normalized source position; its task is to determine whether the acoustic event represents a vehicle passing the sensor and detecting its movement direction. The acoustic probes were mounted inside intelligent lamps that illuminate the roadways depending on the volume of traffic. The paper explains how accurately traffic can be monitored through directional noise analysis and shows the resulting application to smart cities. [The project has been subsidized by the Polish National Centre for Research and Development (NCBR) from the European Regional Development Fund No. POIR.04.01.04/2019 entitled: INFOLIGHT—“Cloud-based lighting system for smart cities.”]
Circular synthetic aperture acoustic imaging of spherical targets in cylindrical rod clutter
Authors: LaFrance Juliana J. , Korman Murray S.
Published: June 2021

A model apparatus has been built to demonstrate acoustic imaging of several spherical targets in cylindrical clutter. Reflective ultrasonic tomography imaging was chosen because the medical community, using photo-acoustic tomography imaging, utilizes a similar back-projection imaging algorithm. The experiment involves suspending an ultrasonic transducer unit (resonant frequency 1.0 MHz) in an aquarium filled with water. The transducer (sender-receiver) generates a 5-cycle tone burst. The circular plane array transducer diameter is D = 1.27 cm. Its wavelength is 1.48 mm (using c = 1482 m/s). The target, located 15 cm from the source, consists of two 0.64 cm diameter metal spheres separated by 5 cm. A mechanical structure of thin perforated disks (10 cm diam) comprise a step-motor controlled rotational platform that supports the targets and slender stainless steel cylindrical vertical rods (2 mm diameter, 10 cm long) that serve as the clutter. Received echoes versus time (data sets) were measured at 10° rotation increments of the structure (from 0° to 360°) for back-projecting the 2-D image reflectance of the targets among the clutter (using Mathematica®). The original apparatus and supporting electronics were built by Madeline Bell for her USNA Capstone research (Fall 2020) involving scattering from cylindrical targets.
Improving our understanding on non-occupational noise-induced hearing loss
Authors: Neitzel Richard L.
Published: June 2021

Noise is among the most common occupational and non-occupational exposures globally. As a result, the public health burden of noise-induced hearing loss is high. Some estimates suggest that roughly 20% of all hearing loss cases result from occupational noise exposure. Occupational noise exposures have been extensively studied and regulated in many countries for decades, and as a result the risk of occupational noise-induced hearing loss associated with different exposure levels and durations has been modeled and quantified. However, non-occupational exposures have not been nearly as well-characterized, and the risk of non-occupational noise-induced hearing loss is not well understood. This presentation will describe a systematic review conducted to evaluate the risk of noise-induced hearing loss associated with non-occupational noise. The presentation will also discuss knowledge gaps in our understanding of non-occupational noise exposures, and the need for tools to allow individuals to evaluate their own exposures against recommended non-occupational noise exposure limits, and ideally to share these “citizen-science” data for aggregated analysis. This approach is now being utilized in the Apple Hearing Study, a partnership between Apple, Inc., and the University of Michigan. Details will be provided on the research approaches and some preliminary results from the Apple Hearing Study.
Hearing disorders secondary to infection with SARS-CoV-2
Authors: Le Prell Colleen
Published: June 2021

A recent emerging concern is the relationships between SARS-CoV-2 (COVID-19) and otolaryngological symptoms such as dizziness, tinnitus, hearing loss. Emerging data suggest auditory and vestibular symptoms are more likely with COVID-19 than previous coronaviruses and Middle East Respiratory Syndrome (MERS). Data from recent reports suggest auditory and vestibular dysfunction secondary to COVID-19 may be greater in females than in males, and in patients older than 60 years. This presentation will discuss these emerging data and the possibility that stress and anxiety during COVID-19 recovery may further contribute to perceptions of exacerbated tinnitus. One factor that may increase anxiety is perceived lockdown-related stress, which has been associated with worsening of tinnitus distress in the absence of COVID-19 infection. A second factor linking increases in anxiety with COVID-19 is increased concern about communication needs as expressed by patients with hearing loss, based on concerns about the negative impact of mask use and social distancing on audibility and communication ability. Finally, it must be noted that proposed treatments for COVID-19 including chloroquinine and hydroxychloroquinine can have auditory side effects including tinnitus, and the doses used in COVID-19 patients significantly exceed doses recommended for treatment of malaria which increases the likelihood of side effects.
Elastic properties of iron and tantalum at high pressure and temperature
Authors: Rowland Richard L. , Sturtevant Blake
Published: June 2021

Iron and tantalum have many important applications in tools, infrastructure, and electronics. In service, metallic parts can experience extreme stresses and temperatures (e.g., jet engine components, chemical processing equipment, supports for large structures), thus it is important to understand their elastic properties as a function of both pressure and temperature in order to allow engineers to appropriately design components using these materials. To determine these properties, we measured sound speeds and densities of Fe and Ta samples as a function of pressure and temperature. These measurements were performed in a large volume hydraulic pressure cell in situ at the Advanced Photon Source. Ultrasound time-of-flight was measured using the pulse-echo method and the sample dimensions were measured using x-ray radiography. x-ray diffraction was used to determine the sample densities. The longitudinal and shear sound speeds and the density measurements were combined to determine the bulk, Young’s, and shear moduli and Poisson’s ratio as pressure and temperature was changed. This talk will present these elastic properties as a function of pressure (up to 7 GPa) and temperature (up to 1000 °C). Finally, electron microscopy techniques will be discussed as a method of quantifying texture evolution during sample compression.
A listening laboratory-based approach to teaching clinical phonetic transcription
Authors: Perrachione Tyler K. , Oppenheimer Barbara B.
Published: June 2021

Knowledge of acoustic and articulatory phonetics is fundamental to learning applied phonetic transcription skills during (pre-) clinical training in speech-language pathology. Furthermore, knowledge of acoustic and articulatory phonetics is foundational to success in advanced speech science coursework and research. We recently implemented extensive revisions to our undergraduate phonetics course aimed at improving students’ ability to deploy conceptual knowledge about acoustics and articulation in developing their phonetic transcription skills, and especially in applying these skills to phonetic transcription of developmental and disordered speech. The paramount revision incorporates a weekly, collaborative listening and transcription lab led by the instructor and modelled on listening exercises in foreign language classes. Lab worksheets train transcription skills by integrating aural and acoustic analysis of speech in diverse contexts, from idealized citation speech through connected speech from children and adults with developmental or acquired phonological and speech motor disorders. Transcription skills are refined and enhanced by progressing from simple to complex applications both within and across labs. Exercises integrate visualization of speech acoustics with transcription to improve students’ familiarity with waveforms and spectrograms. Course evaluations reveal students’ positive valuation of lab experiences, and follow-up assessments demonstrate retention of concepts and skills.
Experiential learning of categorical perception
Authors: Hilger Allison I.
Published: June 2021

Categorical perception can be a complicated topic for undergraduate students to grasp. In this presentation, I will share how I use experiential learning to help students understand categorical perception by allowing them to 'participate' in the original Liberman et al. (1957) study.
Spatial variation of sediment geoacoustic properties at the Seabed Characterization Experiment site
Authors: Yang Jie , Jackson Darrell R. , Goff John
Published: June 2021

The Seabed Characterization Experiment, sponsored by the Office of Naval Research, was carried out 5 March–10 April, 2017 (SBCEX17) on the New England Mud Patch, approximately 100 km south of Martha’s Vineyard. The main SBCEX17 experimental site covers an area of 15 km × 30 km with water depth in the range of 75–80 m. The Sediment Acoustic-speed Measurement System (SAMS) is designed to measure sediment sound speed and attenuation simultaneously over the surficial 3 m of sediments. Sediment sound speed results in the frequency band of 2–10 kHz can be found in an earlier publication (IEEE JOE, doi:10.1109/JOE.2019.2946004). During SBCEX17, SAMS was successfully deployed at 18 sites, which were chosen to be co-located with gravity or piston cores that were collected during the two recent survey cruises in 2015 and 2016. In this talk, our previous results are extended to include both sound-speed and attenuation. The frequency range is widened, and preliminary results for the dependence of sediment sound-speed and attenuation on both range and depth are presented. Sediment geoacoustic properties obtained by SAMS at the 18 sites are compared with historical and recent sediment property surveys giving information on bottom layering, porosity, and grain size. [Work supported by ONR.]
Mud as a porous medium
Authors: Chotiros Nicholas P.
Published: June 2021

Since marine mud supports shear waves, it must have an elastic, though fragile, frame. It is also saturated with seawater, therefore it could be modeled as a porous medium. It is an unusual porous medium for a number of reasons. The boundary between the skeletal frame and the pore fluid is difficult to define. The effective porosity of the skeletal frame is not the same as the bulk fluid fraction. The chemistry of mud suggests that a fraction of the water is an integral part of the skeletal frame. Similarly, a fraction of the solid particles may be suspended in the pore fluid. The structure of the skeletal frame is a function of several factors, including salinity of the water and mineralogy of the clay particles. Porous media have two main loss mechanisms: losses in the skeletal frame and viscous losses due to relative motion between the frame and the pore fluid. In the case of marine mud, the frame losses may be modeled as a relaxation process. The measurements from the Seabed Characterization Experiment show it has a spectrum of relaxation frequencies, consistent with a stationary creep process. [Work supported by ONR, Ocean Acoustics Program.]
Applied research gets big role in Biden's budget
Authors: Mervis Jeffrey , Malakoff David
Published: June 2021

2022 spending plan envisions new entities for translating basic research into practical tools.
Image sleuth faces legal threats
Authors: O'Grady Cathleen
Published: June 2021

Scientists rally around Elisabeth Bik after accusations of harassment and blackmail.
NAS ousts member for first time, for sexual harassment
Authors: Kaiser Jocelyn
Published: June 2021

Academy removes astronomer Geoffrey Marcy.
An early Miocene extinction in pelagic sharks
Authors: Sibert Elizabeth C. , Rubin Leah D.
Published: June 2021

Mysterious mass extinction

The term “shark” inspires predictable images of stealthy and streamlined marine predators that are key components of modern ecosystems. Studying shark teeth buried in deep sea sediment, Sibert and Rubin reveal that current shark diversity is a small remnant of a much larger array of forms that were decimated by a previously unidentified major ocean extinction event (see the Perspective by Pimiento and Pyenson). The extinction led to a reduction in shark diversity by more than 70% and an almost complete loss in total abundance. There is no known climatic and/or environmental driver of this extinction, and its cause remains a mystery. Modern shark forms began to diversify within 2 to 5 million years after the extinction, but they represent only a minor sliver of what sharks once were.

Science
, aaz3549, this issue p.
1105
; see also abj2088, p.
1036
The first 5 years of gravitational-wave astrophysics
Authors: Vitale Salvatore
Published: June 2021

Doing astronomy with ripples in spacetime

General relativity predicts that moving massive objects generate gravitational waves, ripples in spacetime that propagate at the speed of light. Direct detection of gravitational waves was first announced in February of 2016. Vitale reviews the scientific results of gravitational wave astronomy over the subsequent 5 years. About 50 events have been detected, mostly the mergers of binary black holes. The mass distribution of those events is unlike previously known black holes and constrains the evolution of massive stars. A binary neutron star merger was detected in both gravitational waves and electromagnetic radiation, a form of multi-messenger astrophysics. Tests of general relativity and cosmological measurements have also been performed.

Science
, abc7397, this issue p.
eabc7397
Summer reading 2021
Solving Public Problems: A Practical Guide to Fix Our Government and Change Our World
,
Beth Simone Noveck
, Yale University Press, 2021, 448 pp.
Technically Food: Inside Silicon Valley's Mission to Change What We Eat
,
Larissa Zimberoff
, Abrams Press, 2021, 240 pp.
Unwell Women: Misdiagnosis and Myth in a Man-Made World
,
Elinor Cleghorn, Dutton
, 2021, 400 pp.
The Uncommon Knowledge of Elinor Ostrom: Essential Lessons for Collective Action
,
Erik Nordman
, Island Press, 2021, 256 pp.
The Ascent of Information: Books, Bits, Genes, Machines, and Life's Unending Algorithm
,
Caleb Scharf
, Riverhead Books, 2021, 352 pp.
A Quantum Life: My Unlikely Journey from the Street to the Stars
,
Hakeem Oluseyi and Joshua Horwitz
, Ballantine Books, 2021, 368 pp.
Blue: In Search of Nature's Rarest Color
,
Kai Kupferschmidt
, The Experiment, 2021, 224 pp.
The Memory Thief and the Secrets Behind How We Remember: A Medical Mystery
,
Lauren Aguirre
, Pegasus Books, 2021, 336 pp.
Authors: Ivory Ming , Funk Anna , Sutherland Stephani , Goulet Tamar L. , Kozlov Max , Gamillo Elizabeth , Ackerman Daniel , Gastel Barbara
Published: June 2021

A journalist probes the tech companies racing to entice consumers—and investors—with futuristic foods. An outsider documents his ascent in academia. A policy expert proposes a human-centered approach to solving society's problems. From an ode to azure to a deep dive into data, this year's summer reading picks—reviewed by alumni of the AAAS Mass Media Science & Engineering Fellows program—offer readers fresh perspectives on timely scientific topics. Confront the biases that have long imperiled women's health, probe the mysteries of memory, celebrate a prescient economist, and more, with the books reviewed below.
Come on, CDC, we need you
Authors: Thorp H. Holden
Published: June 2021

The US Centers for Disease Control and Prevention (CDC) has had a rough few weeks. At first, it was criticized for being too cautious about its mask guidance for vaccinated individuals. Then, when it abruptly changed its mask recommendation for those who had been vaccinated, it was criticized for acting suddenly and without clearly explaining the reason for the new guidance and what it meant for the unvaccinated. Meanwhile, author Michael Lewis released a bestseller about problems at the CDC that go back decades, with local and state public health officials fighting pandemics in the face of inaction and confusion from the agency. The CDC is in a difficult position: In the course of carrying out its appointed task of communicating science and promoting the best health practices, it can also appear to be making policy—and that is not supposed to be its job. But where do you draw the line between proffering advice and promulgating policy? Maybe the CDC and the administration need to step back and consider if there is a better way for the agency to protect public health.
Antibody reactivity to human and vervet cytomegalovirus early antigen(s) in sera from patients with active cytomegalovirus infections and from asymptomatic donors
Authors: Waner J L , Biano S A
Published: June 2021

Human fibroblasts were infected with vervet cytomegalovirus (VCMV) and cultured in medium containing 50 micrograms of cytosine arabinoside per ml for 72 h. Early antigens (EAg) were detected in the nuclei of infected cells by an indirect fluorescent antibody test with human sera having antibody to EAg of human cytomegalovirus (HCMV). Sera from patients with serological and/or virological evidence of active HCMV infection and from asymptomatic blood donors were examined for antibody activity with the HCMV and VCMV EAg's. The HCMV and VCMV EAg's were comparable in detecting levels of antibody activity and fluctuations in antibody titer of paired sera from patients. A total of 81% of patient sera reactive with HCMV EAg were also reactive with VCMV EAg. In contrast, only 14% of the asymptomatic donor sera reactive with HCMV EAg were also reactive with VCMV EAg. The VCMV EAg, therefore, appeared to differentiate latent from active infections in humans more effectively than did HCMV EAg.
Two strains of Vibrio species with unusual biochemical features isolated from ear tracts
Authors: Hansen W , Crokaert F , Yourassowsky E
Published: June 2021

A strain of vibrio cholerae Heiberg type II, not agglutinable with any of the eight antisera corresponding to Heiberg's groups, and a nonmotile, methyl red-positivs of chronic external otitis.
Two forms of Staphylococcus aureus in blood of patients with staphylococcal sepsis
Authors: Musher D M , Baughn R E , Young E J
Published: June 2021

Two distinctly different and stable forms of Staphylococcus aureus were isolated from the blood of each of two patients with staphylococcal sepsis. In each case, one form was hemolytic and the other nonhemolytic, although both had the same biochemical reactions, phage types, and antibiotic susceptibilities, and both were virulent for mice. Variant forms of S. aureus may be selected in vivo by host factors and may be responsible for causing and/or perpetuating infection.
Solid-Phase Microtiter Radioimmunoassay Blocking Test for Detection of Antibodies to
Escherichia coli
Heat-Labile Enterotoxin
Authors: Greenberg Harry B. , Levine Myron M. , Merson Michael H. , Sack R. Bradley , Sack David A. , Valdesuso Jose R. , Nalin David , Hoover David , Chanock Robert M. , Kapikian Albert Z.
Published: June 2021

The development of a solid-phase microtiter radioimmunoassay blocking test to detect serum antibody to
Escherichia coli
heat-labile enterotoxin is described. The assay is easy to perform and quantitate, and it is sensitive and specific.
Biochemical, Enzymatic, and Serological Differentiation of
Peptococcus indolicus
(Christiansen) Sørensen from
Peptococcus asaccharolyticus
(Distaso) Douglas
Authors: Schwan Olof
Published: June 2021

Peptococcus indolicus
(formerly
Micrococcus indolicus
) is an asaccharolytic anaerobic coccus that is frequently isolated from udder secretions from cases of heifer and dry-cow mastitis (summer mastitis). To facilitate better identification and its differentiation from
Peptococcus asaccharolyticus
, a variety of biochemical, enzymatic, and serological properties were studied. Seventy-nine strains of
P. indolicus
of bovine origin and 10 strains of
P. asaccharolyticus
of human origin were examined using the API 20A and API-ZYM test kit systems. In addition, production of extracellular enzymes by using sensitive substrate-containing agar plate tests, production of peptocoagulase (a plasma-clotting factor), hemolytic properties, metabolic end products by gas chromatography, and serological characteristics with a set of
P. indolicus
typing antisera were investigated.
P. indolicus
and
P. asaccharolyticus
were not satisfactorily differentiated solely by the API 20A system.
P. indolicus
differed from
P. asaccharolyticus
in producing H
2
S, reducing nitrate to nitrite, producing peptocoagulase, possessing alkaline phosphatase, and producing large amounts of propionate from lactate. Moreover, none of the strains of
P. asaccharolyticus
was typable with the
P. indolicus
typing antisera. The majority (88%) of
P. indolicus
strains also gave weak hydrolysis of ribonucleic acid, and 6 out of 79 produced deoxyribonuclease. All strains in this study were sensitive to metronidazole (5 μg) by disk diffusion tests.
Evaluation of Sulfamethoxazole- Trimethoprim Blood Agar Plates for Recovery of Group A Streptococci from Throat Cultures
Authors: Kurzynski Terrence A. , Meise Cheryll K.
Published: June 2021

We compared the selective blood agar medium of Gunn et al. (J. Clin. Microbiol. 5:650-655, 1977) which contains sulfamethoxazole plus trimethoprim (SXT-BA) to the conventional blood agar surface plate (SBA) and a modified blood agar pour plate plus broth method for the recovery of group A streptococci from throat swabs. The influence of CO
2
and ambient air incubation of the SXT-BA and SBA plates was also evaluated. A total of 696 throat swabs from symptomatic children were cultured simultaneously by the five methods and observed after overnight incubation; 204 positive cultures were detected overall. Recovery rates of each individual method were: SXT-BA (CO
2
), 90.7%; SXT-BA (air), 87.7%; pour plate plus broth, 83.3%; SBA (CO
2
), 79.4%; and SBA (air) 77%. Approximately one-half of the false-negative cultures in the SXT-BA (CO
2
) and SXT-BA (air) methods had colony counts of ≥10 to 100 colonies per plate. In contrast, for the SBA (CO
2
), SBA (air), and pour plate plus broth methods, approximately 70% of the false-negative cultures had colony counts of ≥10 to 100/plate. False-positive cultures obtained by the SXT-BA (CO
2
) and SXT-BA (air) methods were 11 and 12.7%, respectively—one-half as high as the rates obtained by the remaining methods. Beta-hemolytic streptococci, groups C, F, and G, are inhibited on the SXT-BA plates and were the primary cause of the higher false-positive rates on SBA and pour plate plus broth methods. An additional 3% positive cultures were obtained by incubating SXT-BA (CO
2
) plates up to 48 h before discarding as negative. We recommend either the SXT-BA (CO
2
) or the SXT-BA (air) method with up to 48 h of incubation for routine use in throat cultures.
Sensitivity, precision, and accuracy of the Y1 adrenal cell enterotoxin assay
Authors: Tenney J H , Smith T F , Washington J A
Published: June 2021

The Y1 adrenal cell assay for heat-labile enterotoxin (LT) was found to be relatively insensitive for filtrates of toxigenic Escherichia coli H10407. When observations were made blindly and subjected to rigorous controls, reliable detection of LT occured only at filtrate dilutions from 1:4 to 1:10. Detection of LT was unreliable when E. coli H10407 was mixed with another enteric organism. Overall, 7.1% of observers' reports from a single assay were imprecise, and 2.6% would have resulted in errors in detection of LT; however, triplicate assays prevented false positive reports of LT detection. Routine testing for LT production in the clinical diagnostic laboratory awaits a simpler, more sensitive, and more direct method of testing stool specimens.
Chromogenic cephalosporin spot test to detect beta-lactamase in clinically significant bacteria
Authors: Montgomery K , Raymundo L , Drew W L
Published: June 2021

lactamase production. Reacteroides melaniongenicus, 14
Selective and differential medium for isolation of Clostridium difficile
Authors: George W L , Sutter V L , Citron D , Finegold S M
Published: June 2021

Clostridium difficile is a recognized cause of pseudomembranous (antimicrobial agent-associated) colitis and may be one of the causes of antimicrobial agent-induced diarrhea. A selective and differential agar medium that contains cycloserine, cefoxitin, fructose, and egg yolk (CCFA) was developed to facilitate the isolation of C. difficile from fecal specimens. Quantitative cultures of 16 stock strains of C. difficile on this medium (and on a medium containing cycloserine, fructose, and egg yolk) yielded counts equivalent to those obtained on blood agar; other media selective for clostridia, including Clostrisel agar, reinforced clostridial agar plus 0.2% para-cresol, and egg yolk-neomycin agar (the latter was inoculated with cultures subjected to prior heat shocking), were also tested and found to be inhibitory to the growth of C. difficile. Of 28 fecal or colostomy effluent specimens cultured on the above media, 14 yielded C. difficile. CCFA was found to be the most sensitive and selective of these media for the recovery of C. difficile. Colonies of C. difficile growing on CCFA had distinctive morphological and fluorescent properties which were sufficient for presumptive identification. CCFA should provide a rapid method for the screening of fecal specimens from patients with antimicrobial agent-associated diarrhea or colitis for C. difficile.
Comparison of the API 20E and Oxi/Ferm systems in identification of nonfermentative and oxidase-positive fermentative bacteria
Authors: Oberhofer T R
Published: June 2021

The API 20E and Oxi/Ferm systems were tested in parallel to identify nonfermentative bacteria and oxidase-positive fermentative bacteria. Test strains consisted of consecutive clinical isolates, with stock cultures used to supplement those species infrequently recovered. The two microsystems, as well as tubes of triple sugar iron, motility, cetrimide, and oxidative glucose media, were inoculated by each worker for each organism. Identification of each isolate was by the protocol of the manufacturers, with supplemental tests and flagella stains performed when necessary. Concurrent identification was undertaken with a conventional system against which the results of the two systems were compared for accuracy. There was a 95.3% accuracy in identification by the Oxi-Ferm system and 88.9% by the API system. Almost one-fourth of all identification attempts with the API required computer assistance, and most of these were for oxidase positive bacteria. Because of this, and because the API system showed greater accuracy in identification of the oxidase-negative bacteria, it seems best suited for identification of these organisms (P. maltophilia, A. anitratus, and A. lwoffi). The Oxi/Ferm system is technically less cumbersome than the API and is well suited for both groups of organisms.
Rapid diagnosis of Pseudomonas aeruginosa urinary tract infections by radioimmunoassay
Authors: Kohler R B , Wheat L J , White A
Published: June 2021

A solid-phase radioimmunoassay designed to detect serotype 6 Pseudomonas aeruginosa antigens was evaluated for its ability to rapidly diagnose urinary tract infections. Twelve P. aeruginosa serotypes were easily differentiated in the assay from eight other gram-negative bacterial species. During log-phase growth, the assay detected antigens in culture when approximately 10(6) or more serotype 6 P. aeruginosa organisms were present. Both cell-associated and solubilized antigens were detected. The assay detected antigens in 13 of 17 urine specimens which grew greater than 10(5) P. aeruginosa, 3 of 38 which grew other gram-negative rods, and none of 83 with no growth. Two of the three positive specimens from the other gram-negative rod group probably also contained P. aeruginosa. No preincubation of the urine specimens was required, and results were available within 2.5 h. The assay represents an improvement over other procedures for rapidly diagnosing urinary tract infections in that it allows diagnosis by species and should be adaptable to semiautomation.
Serological study of trichloroacetic acid extracts of Bacteroides fragilis
Authors: Abshire R L , Dowell V R , Lombard G L
Published: June 2021

Immunodiffusion techniques were used on trichloroacetic acid extracts from 10 strains of Bacteroides fragilis in detecting precipitating antibodies against this species in immune rabbit sera. Species and even strain specificities were observed in these precipitin reactions. Multiple antigens were detected in the extracts from some strains, whereas only one precipitin band per extract developed during agar-gel diffusion tests of others. The antigen extracts were found to be both heat stable and resistant to hydrolysis by alpha-chymotrypsin. Four serological patterns were demonstrated in homologous and heterologous reactions with the B. fragilis. antigen-antibody systems used. The results showed that some strains were serologically distinct from others, indicating that the strains tested are of more than one serotype.
Haemophilus influenzae Type D meningitis
Authors: Viner J P , Massanari R M
Published: June 2021

This report describes an unusual pathogen associated with post-traumatic meningitis. Haemophilus influenzae type D was isolated from both cerebrospinal fluid and blood of this patient with meningitis.
Complement-fixing immunoglobulin M antibody response in patients with infantile gastroenteritis
Authors: Abe Y , Inouye S
Published: June 2021

Complement-fixing immunoglobulin M antibody to infantile gastroenteritis virus (a rotavirus) was detected with highest sensitivity when the antibody-antigen-complement mixture was incubated at 37 degrees C for 1 h prior to the addition of sensitized sheep erythrocytes. Sucrose gradient centrifugation of sera collected sequentially from four patients after infection detected 19S complement-fixing antibody up to 5 weeks, with highest titers at 1 week, after the onset of illness. Treatment of the whole sera with 2-mercaptoethanol decreased complement-fixing titers only up to 2 weeks after onset of illness.
Liver Abscess Caused by
Haemophilus paraphrohaemolyticus
Authors: Douglas George W. , Buck Larry L. , Rosen Clifford
Published: June 2021

Haemophilus paraphrohaemolyticus
was isolated in pure culture from a liver abscess in a 73-year-old man.
Partially purified antibodies used in a solid-phase radioimmunoassay for detecting candidal antigenemia
Authors: Poor A H , Cutler J E
Published: June 2021

The development of a solid-phase radioimmunoassay procedure for the detection of Candida albicans antigens in serum of mice is described. Antibodies against C. albicans that were used in the radioimmunoassay procedure were partially purified from immune serum by a C. albicans antigen-coupled affinity column. Elution of anti-C. albicans antibodies from the column was by glucose and mannose; 4 mg of protein was recovered per ml, which contained 50% of the candidal agglutinin activity of immune serum. Also, 81% of the protein (partially purified antibody) recovered was adsorbed by whole C. albicans cells. Anti-C. albicans antibodies were either coupled to Sepharose 4B for use as the solid phase to bind candidal antigen in serum of infected animals, or radioiodinated (125I) for use as a tracer molecule to bind to the candidal antigen solid-phase complex. Although control experiments indicated that at least 100 ng of candidal antigen should be present in a serum specimen for a positive radioimmunoassay test, candidal antigenemia was detected in 70.4% of infected mice even in cases where blood cultures for C. albicans were negative. With further refinement and adaptability to human serum, the radioimmunoassay test may become a helpful tool for use in the diagnosis of systemic candidiasis.
Indirect immunofluorescence test for serodiagnosis of Legionnaires disease: evidence for serogroup diversity of Legionnaires disease bacterial antigens and for multiple specificity of human antibodies
Authors: Wilkinson H W , Fikes B J , Cruce D D
Published: June 2021

Evidence obtained by others who used direct immunofluorescence staining to demonstrate serological differences among strains of Legionnaires disease bacterium prompted this study of parameters influencing the ability of the indirect immunofluorescence test to detect human antibodies to Legionnaires disease bacterium. A total of 25 Legionnaires disease bacterium strains, representing four serogroups, were used as immunofluorescence antigens to test selected human sera. The use of diethyl ether in preparing the antigens was discontinued when it was found that titers against ether-killed group 2 (Togus 1-like) antigens were impossible to determine. Instead, heat-killed suspensions of Legionnaires disease bacterium in 0.5% buffered normal chicken yolk sac were used to show the serogroup diversity of the strains and the serogroup specificity of the antibody response of some, but not all, patients with serological evidence of Legionnaires disease. These studies suggest that multiple antigens should be used in serological tests for Legionnaires disease. Furthermore, the fact that some sera contain antibodies that bind equally well to strains of all four serogroups implies that demonstration of a fourfold increase in titer of paired sera when tested with a single antigen should not be interpreted as evidence of infection with a strain of the same serogroup.