bluuebunny/crossref_metadata_2025 huggingface dataset:
Concept for a study on community responses to low sonic boom in Europe
Authors: Schreckenberg Dirk , Grossarth Stephan , Meliveo Luis , van Oosten Nico
Published: June 2021

In 2018, NASA was the first to assess noise annoyance by low-sonic booms among a population not used to hearing any of the acoustical phenomena associated with an aircraft flying at supersonic speeds (QSF18 study). Meanwhile, within the EU-project RUMBLE, data are collected, and literature reviewed used for research on community responses to low sonic boom demonstrator overflights. We present recommendations for such a field study, comprising NASA and RUMBLE studies' findings and other European efforts emphasizing items discussed by NASA and European researchers in the aftermaths of the first QSF18 results. We propose a study design for the CRLSB study in different European climate zones. A low-fidelity simulation model has been developed to pre-select test sites, supplemented by a more detailed impact model (NENA) for final site selection and preparation of the survey. We identified an approach of mixed survey modes, including experience-sampling procedures, as the most desirable modus operandi for community response assessment. Further, we propose a method for calculating desired sample sizes when applying linear mixed-effects modeling to data collected from a continental field study. [This project has received funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 769896.]
Effects of bandwidth limitations on low-boom perceived level
Authors: Anderson Mark C. , Gee Kent L. , Durrant J T. , Novakovich Daniel J. , Loubeau Alexandra
Published: June 2021

Estimating sonic boom noise levels during community noise testing of low-boom supersonic aircraft such as the NASA X-59 can be challenging because of bandwidth limitations caused by ambient noise contamination of boom recordings. This paper describes the effect of spectral bandwidth limitations on a candidate sonic boom metric for community response: the perceived level (PLdB). This metric was calculated using spectral data of measured sonic booms from NASA’s Quiet Supersonic Flights 2018 (QSF18) test campaign. Spectral data were obtained using a 650 ms time window for both the boom and the ambient recordings, with the ambient recording immediately preceding the detected boom, and the measurement bandwidth estimated using the signal-to-noise ratio (SNR) at each frequency. Analysis of several booms at four different measurement stations, each with several measurement configurations, shows that not accounting for limited bandwidth can add several decibels to the sonic boom metrics. The effects of measurement location and instrumentation are discussed. Future work may include developing methods for how to account for limited bandwidth, including potential filtering and spectral extrapolation methods. [Work supported by NASA Langley Research Center through the National Institute of Aerospace.]
Comparing the differences in robustness between interaural time delay calculation methods
Authors: Neal Matthew , Zahorik Pavel
Published: June 2021

The interaural time delay (ITD) is a primary cue to lateral sound source direction and can be calculated from a head-related impulse response (HRIR). Although many ITD calculation techniques utilize cross-correlation, recent work suggests that for horizontal plane HRIRs, ITD calculation based on HRIR onset threshold may better match human perception of source location. The goal of the current study is to more comprehensively compare ITD calculation methods across a large sample of HRIRs. 2448 ITD calculation methods were compared using 42 240 HRIRs from the HUTUBS database (440 directions from 96 individuals). Within each method and individual, the calculated ITD function was compared to a spatially smoothed ITD function using a 10th-order spherical harmonic truncation. When large deviations from the smoothed version occurred (>250 μs), the method was tagged as being non-robust to calculation artifacts. Although the robustness of the onset threshold technique was found to be highly dependent upon threshold level and low-pass filter parameters, proper selection of these parameters resulted in little to no calculation artifacts and superior performance to other calculation methods. Improvements in the robustness of ITD calculation may help to optimize virtual auditory displays or HRIR personalization procedures using the minimum-phase plus ITD model.
Relationship between psychological and physiological measurements of auditory sensitivity in adolescents with attention-deficit/hyperactivity disorder
Authors: Moore Alexandra , Sydenstricker Shelby , Nagao Kyoko
Published: June 2021

Abnormal auditory sensitivity is common in patients with ADHD, however, auditory sensitivity issues have not been well-studied in ADHD. This study investigated auditory sensitivity in ADHD using psychological and physiological measures. A group of 13 adolescents aged 13 to 19 with a current ADHD diagnosis (ADHD group) and a group of 24 adolescents with normal development (control group) participated in this study. Acoustic reflex thresholds (ART) were obtained using pure-tone stimuli (500 Hz and 1 kHz) and wideband noise. Each stimuli was presented to each ear from 56dB to 104 dB in a 2-dB step. Loudness discomfort levels (LDL) were also obtained using two stimuli (500 Hz and wideband noise) in each ear. ART and LDL were collected without daily stimulant medication in the ADHD group. Questions related to auditory sensitivity were obtained using the Adolescent/Adult Sensory Profile. Preliminary results indicated no significant correlation between ARTs and LDLs and between ARTs and sensory profile scores in both groups. We found a weak correlation between ARTs and some sensory profile scores in the ADHD group. The results suggested a mismatch between ARTs and behavioral measures on auditory sensitivity. [Work supported by the ACCEL grant (NIH U54GM104941), the State of Delaware, and Nemours Foundation.]
Effect of rhythm-based prediction on medial olivocochlear reflex and delta oscillations
Authors: Ishizaka Yuki , Otsuka Sho , Nakagawa Seiji
Published: June 2021

The medial olivocochlear reflex (MOCR) is an efferent feedback activated by acoustic stimulation. Our previous studies showed that a preceding sound expedites MOCR, which suggests that temporal expectation about the timing of stimulus occurrence can modulate MOCR. In contrast, the temporal structure, e.g., regularity and rhythm, of preceding sequences also contains cues for temporal expectation about the timing of upcoming sounds. Here we investigate whether the regularities of preceding sound sequences can modulate MOCR. Simultaneously, we measured electroencephalography (EEG) delta-band oscillations whose phase-locking was reported to play a role in mediating the effects of anticipation on target detection. The predictability of target occurrence was modulated by adding jitter to the inter-stimulus interval (ISI) of the preceding sound sequence. Both the strength of MOCR and the phase synchronization of EEG delta oscillations decreased with increasing the jitter up to 20% of the ISI and are saturated above that percentage. The similar dependence on the amount of the jitter suggest the involvement of delta oscillations in the predictive control of MOCR based on the regularity of preceding sound sequences.
Acoustic black hole optimization
Authors: Petrover Kayla
Published: June 2021

Acoustic black holes have a tapering profile to create the idealized phenomenon of zero reflection. This phenomenon relies on geometry instead of dampers, so it is an ideal way to remove vibrations without increasing mass or surface area. They can attenuate acoustic and structural vibrations for applications in air, space, ground, and marine vehicles and can be produced in ducts, beams, plates, and wedges. The phenomenon entails wave propagation in an ideal medium where the profile tapers according to the power law shortening the wavelength and decreasing the wave speed. Consequently, the wave’s travel time goes to infinity so that it never reaches the termination and cannot be reflected—creating complete absorption. For the application of a circular duct, thin annular rings of inner radii decrease with the power law to control pressure levels. An infinite number of rings and a final cross sectional area of zero are needed to create an ideal acoustic black hole and is impossible to achieve. However, imperfections create scattering and other losses that increase damping performance. Therefore, various configurations need to be tested to tune parameters such as the amount, thickness, and spacing of tapering rings to produce minimal reflection across a frequency spectrum.
Investigation of an additively manufactured pentamode material using non-contact vibration transmissibility measurements
Authors: Cushing Colby W. , Kelsten Matthew , Norris Andrew N. , Wilson Preston S. , Haberman Michael R.
Published: June 2021

Pentamodal (PM) metamaterials are one potential means to enable concepts from transformation acoustics in underwater applications because they can be designed to support anisotropic longitudinal wave motion over wide frequency bands while simultaneously being impedance matched to water [Su et al., J. Acoust. Soc. Am. 141(6), (2017)]. In three dimensions, PM materials can be fabricated using additive manufacturing (AM) to create elastic lattice structures whose microstructure can be tailored to produce the desired anisotropic sound speed and impedance in a target frequency band. This work presents measurements of the vibrational response of a PM block designed to display anisotropic stiffness. The sample measures approximately 100x100x85 mm and is constructed from titanium using direct metal laser sintering. Measurements were made on a sample mounted on an electro-dynamic shaker providing base excitation between 0.05 and 20i kHz. A scanning laser Doppler vibrometer measured out-of-plane surface velocity with normals both parallel and orthogonal to the excitation axis. The finite extent of the sample introduces geometric asymmetry associated with domain truncation, which is observable in the vibrational modes. Measurements were made for various sample orientations and compared to full-featuredfinite element models. Simulation-experiment comparisons and other findings will be presented and discussed. [Work supported by ONR.]
Achieving optimal attenuation in acoustic waveguides with 3D printed Helmholtz resonators
Authors: Kelsten Matthew , Norris Andrew N.
Published: June 2021

A double root, commonly referred to as an exceptional point (EP), for modal frequencies in a 2D or 3D waveguide can exhibit optimal attenuation rates over a relatively broad frequency range. The key to the phenomenon is that the wall impedance is such that modes coalesce at a complex-valued frequency. In this talk we consider a novel approach to feasibly achieve the aforementioned wall impedance with the use of simple resonators, which can be shown to exhibit mode coalescence at distinct frequencies when treated as a unit cell component of a larger metasurface. Numerical results of several unit cell designs are given to test the boundaries on the following constraints: realizable resonator dimensions, scale separation, and target attenuation goals. To validate the analytical work, experimental setups consisting of additively manufactured Helmholtz resonators incorporated onto a custom-made impedance tube are tested. The dependence of printed resonator quality on theoretical inertial, loss, and stiffness values are discussed in tandem with printing repeatability. Simulated finite element model results will be used as comparative backdrops with the numerical and experimental results. Work supported by NSF.
Relative entropy of machine-learning for long-range sound propagation
Authors: Hart Carl R. , Wilson D. Keith , Pettit Chris L. , Nykaza Edward T.
Published: June 2021

Machine-learning algorithms can provide fast surrogate models when trained on sampled predictions from physics-based numerical models. However, it is unknown whether surrogate data generated from propagation through single realizations of atmospheric turbulence, or from an ensemble of multiple realizations of turbulence, is most suitable for machine-learning models. This study examines the use of a Crank-Nicholson parabolic equation (CNPE) for generating surrogate data, and Latin hypercube sampling for the CNPE input. Two separate datasets are generated for 5000 samples of governing parameters. In the first dataset, each transmission loss field is computed for a single realization of turbulence, whereas the second uses transmission loss from an ensemble of 64 realizations. Errors for various machine learning approaches are evaluated against experimental observations of long-range (out to 8 km) sound propagation. Between experimental and surrogate differences in transmission loss at four ranges, the average deviation from zero relative entropy was quantified. As a measure of dissimilarity between two distributions it is 0.17 for single realizations of turbulence, and 0.29 for 64 realizations of turbulence. Surrogate data generated from single realizations of turbulence agree better with experimental data.
Seabed classification from ship-radiated noise using an ensemble deep learning
Authors: Escobar-Amado Christian D. , Badiey Mohsen , Neilsen Tracianne B. , Castro-Correa Jhon A. , Knobles David P.
Published: June 2021

An ensemble of deep learning algorithms is employed for seabed classification using merchant ship-radiated noise recorded on a single receiver. Five different convolutional neural network (CNN) architectures and one residual neural network (ResNet) are trained on synthetic data generated using 34 seabed types found in the literature from different areas of the world that span from soft-muddy to hard-sandy sediments. Validation results show an accuracy above 97.15% for all the networks using the five-fold cross-validation method. To assess the generalizability performance of the ensemble deep learning, the networks were tested on 69 data samples measured on three VLAs in the Seabed Characterization Experiment in 2017 (SBCEX 2017) from merchant ships passing by close to the receivers. Results show that the most likely sediments were the mud over sand environments inferred in previous geoacoustic inversions for the SBCEX 2017 area with 94% of the predictions from all the trained networks. This work presents evidence that the ensemble of deep learning algorithms has learned how the signature of the sediments is encoded in the ship-radiated noise providing a unified classification result when tested on real-world data. [Work supported by ONR, Contract No. N00014-19-C-2001.]
Synthesis of acoustics of coupled volumes—Perceptual approach
Authors: Woszczyk Wieslaw
Published: June 2021

Connected, acoustically coupled spaces are typically characterized by non-exponential decay with double or multiple slopes. In some cases, two volumes of different absorption characteristics are connected through an aperture that may be opened to vary the engagement between the two acoustics, e.g., the auditorium and the reverb chamber. In a large complex room, acoustic energy emanating from the source will simultaneously and sequentially engage a number of different volumes (regions), depending on how the space is physically laid out, and where the source and receiver are. The regions shape and exchange energy collectively. The listener’s overall room impression will be due to an overlayed mix of spatially and temporally distributed ambient responses reaching the listener or receiver position. In synthesis of complex acoustic spaces, we take a perceptual approach where we combine elements of measured spatial room impulse responses, divide them into meaningful temporal segments, shape their envelopes, and recombine these varied characteristics for multichannel convolution with a source. Different variants of processing the impulse responses create different perceptual outcomes, and a variety of aurally diverse spaces can be created for applications in virtual acoustics and immersive audio production. These perceptual approaches, balancing clarity and reverberation, will be discussed in this presentation.
Array-based focusing of therapeutic ultrasound to the spinal canal
Authors: O'Reilly Meaghan A. , Xu Rui , Martin David
Published: June 2021

The development of clinical-scale technology for non-invasively focusing to the spinal cord has the potential to enable the translation of novel treatments, such as enhanced drug delivery via ultrasound modification of the blood-spinal cord barrier. This talk will present recent simulation and experimental results evaluating array-based focusing to the human spinal canal with non-invasive aberration correction.
Oxygen scavenging using acoustic droplet vaporization while altering droplet diameter and droplet concentration
Authors: Benton Rachel P. , Clark Abby , Nedunuri Manaswini
Published: June 2021

Transiently reducing the bioavailability of oxygen within an ischemic heart at the time of reperfusion may reduce the formation of reactive oxygen species and therefore reduce the amount of cell death. In vitro studies describe how the magnitude of oxygen scavenging changes as perfluorocarbon droplet diameter and droplet concentration are varied under ultrasonic exposure from an EkoSonic intravascular catheter.
Self-demodulation revisited: Effect of nonlinear propagation on stable cavitation from ultrasound contrast agents
Authors: Vagisha  , Bader Kenneth , Shekhar Himanshu
Published: June 2021

Stable cavitation from microbubbles is important for both ultrasound-mediated therapy and contrast-enhanced imaging. Here, we extend the findings of prior studies, which indicate that the self-demodulation of the excitation pulse caused by nonlinear propagation can enhance stable cavitation.
The role of U.S. thermal stress in modulating the vascular transport dynamics in the brain tumors
Authors: Arvanitis Costas , Kim Chulyong , Guo Yutong , Velalopoulou Anastasia
Published: June 2021

We hypothesized that localized thermal stress could change the cerebrovascular transport dynamics in the brain tumor micro-environment. Our findings, using a closed-loop trans-cranial MR guided FUS system, support our hypothesis and provide evidence that spatially controlled thermal stress can enable the development of therapeutic strategies to reduce systemic toxicity while attaining high drug accumulation to the tumor core.
Bubble-enhanced HIFU
Authors: Averkiou Michalakis A. , Juang Eric , Clark Alicia
Published: June 2021

The addition of contrast agent microbubbles during HIFU can increase the temperature dramatically compared to conventional HIFU. Higher microbubble concentrations enhance this phenomenon but they also cause acoustic shadowing along the path of the HIFU beam and thus local injections are preferred over systemic delivery.
On a high-speed hearing measurement considering the age of both ears
Authors: Bae Seong-Geon , Bae Myungjin
Published: June 2021

In order to enrich the human senses, care must be taken not to damage your hearing. Hearing damage suffered in a living environment is difficult to find out because there are few initial symptoms. Existing pure tone hearing test detects whether pure tones are heard well for each frequency for 250–8000 Hz sound, which is mainly used in everyday conversation, but it is inaccurate and takes a long time. Therefore, in this paper, we proposed a high-speed measurement method that can easily and quickly self-measure both ears' hearing damage through an APP of a smart-phone. In this method, nine pure tones that are age-compensated for each voice sub-band are alternately heard in both ears, thereby self-identifying their own hearing damage at high speed. When 18 tone pulses were heard for 27 s per person, 1 out of 12 subjects was identified as suspected of partial hearing damage. When the test subjects were informed of the hearing determination method for the number of hearings, the participants themselves immediately determined whether their hearing was damaged. Eventually, both ears' hearing damage was easily and accurately measured by the method proposed, which took more than 10 min with the existing manual method. As a result, it is possible to maintain a healthy life by simply determining whether or not there is a hearing loss.
A study on the conversion of rhythmic Klaxon sound with an instant touch
Authors: Kim Myung-Sook , Bae Myungjin
Published: June 2021

With more and more cars and more complex road conditions, Klaxon sound is more often used in driving cars. Retaliation psychological driving caused by this sound is causing serious social problems. Therefore, a new rhythmic Klaxon sound is needed to prevent psychological stress and retaliation from being triggered. If rhythm or tempo is given to the existing Klaxon sound, it can relieve the other driver's retaliatory psychology or the pedestrian's surprise. However, since the existing Klaxon sound has been used for more than a hundred years, a new method to switch to the rhythmic Klaxon is proposed depending on whether the handle is touched instantly. This paper proposes a line controller that converts the Klaxon switch of the handle to a rhythmic Klaxon sound when an instant ON-OFF touch occurs within 0.2 s. Existing Klaxon's retaliatory psychology appeared as a delta wave and beta wave, respectively, in EEG, and the degree of surprise was obtained differently according to the listening distance and sound level. The noise level felt when performing the object test was −15 dB lower in the rhythmic Klaxon sound than before. The MOS-test result of the listener group (100 people)'s preference for rhythm Klaxon sound was 4.3 or higher. In conclusion, if you are using the existing Klaxon sound and then touch the handle momentarily and keep turning ON, the rhythm sound that awakens a great awareness even with a low-level horn sound can be used immediately.
Preventing noise induced hearing loss: Issues and challenges facing musicians
Authors: Chesky Kris
Published: June 2021

National and state education standards now require collegiate and public school music programs to address concerns for noise induced hearing loss related to consuming, learning, and performing music. The expected outcomes include ensuring awareness, knowledge, and self-efficacy for managing music-related exposures and activities. Based on extensive efforts to implement these standards in a large College of Music and across an independent school district that includes numerous middle and high school choir, orchestra, and band programs, this session will provide insight into the various challanges and opportunities related to positively influencing cultural norms and traditions within the music discipline.
Comment on Trophic strategy and bleaching resistance in reef-building corals
Authors: Thibault Martin , Lorrain Anne , Houlbrèque Fanny
Published: June 2021

We show how to foresee and account for risks in applying the SIBER framework to coral trophic ecology.
Cloning of trg, a gene for a sensory transducer in Escherichia coli
Authors: Harayama S , Engström P , Wolf-Watz H , Iino T , Hazelbauer G L
Published: June 2021

Clones of trg, a gene which codes for a chemotactic transducer, were isolated linked to ColE1 and pBR322 vectors. Studies with the hybrid plasmids demonstrated unequivocally that trg is the structural gene for methyl-accepting chemotaxis protein III. The Trg protein was found to be structurally complex, electrophoresing as a series of seven bands on high-resolution sodium dodecyl sulfate-polyacrylamide gels. The multiplicity of bands is a function of the activity of cheR, which codes for a methyltransferase, and of cheB, which codes for a demethylase. It appears that Trg, a quantitatively minor transducer, resembles the two major transducer proteins, Tsr and Tar, in that all three are multiply methylated and also multiply modified in a second way which requires an active cheB gene. However, preliminary analysis of the Trg protein indicated that it is significantly less related structurally to the Tsr or Tar protein than those two transducers are to each other. This implies that the features of multiple methylation and cheB-dependent modification are likely to be critical for the common physiological functions in chemotactic excitation and adaptation performed by all three transducers.
DNA replication in a diploid strain of Saccharomyces cerevisiae homozygous for the rad6-1 mutation
Authors: Haładus E , Swietlińska Z , Zaborowska D , Zuk J
Published: June 2021

The generation time of a diploid strain homozygous for the rad6-1 mutation was 160 min, and the duration of the S phase was 80 min; in the parental heterozygote, these values were 90 and 40 min, respectively. Analysis of DNA sedimentation in an alkaline sucrose gradient revealed that heterozygote high-molecular-weight DNA appeared after 60 min, and homozygote high-molecular weight DNA only after a 100-min pulse.
Cytoplasmic transfer of oligomycin resistance during protoplast fusion of Saccharomycopsis lipolytica
Authors: Matsuoka M , Uchida K , Aiba S
Published: June 2021

Mitotic segregation of oligomycin resistance and oligomycin sensitivity was observed among the prototrophic progeny of protoplast fusion between drug-resistant and drug-sensitive complementary auxotrophs of Saccharomycopsis lipolytica. The transfer of oligomycin resistance by protoplast fusion without karyogamy suggests a cytoplasmic inheritance of this drug resistance determinant.
Alterations in the phospholipid composition of Rhodopseudomonas sphaeroides and other bacteria induced by Tris
Authors: Donohue T J , Cain B D , Kaplan S
Published: June 2021

Alterations in the phospholipid head group composition of most strains of Rhodopseudomonas sphaeroides, as well as Rhodopseudomonas capsulata and Paracoccus denitrificans, occurred when cells were grown in medium supplemented with Tris. Growth of R. sphaeroides M29-5 in Tris-supplemented medium resulted in the accumulation of N-acylphosphatidylserine (NAPS) to as much as 40% of the total whole-cell phospholipid, whereas NAPS represented approximately 28 an 33% of the total phospholipid when R. capsulata and P. denitrificans respectively, were grown in medium containing 20 mM Tris. The accumulation of NAPS occurred primarily at the expense of phosphatidylethanolamine in both whole cells and isolated membranes of R. sphaeroides and had no detectable effect on cell growth under either chemoheterotrophic or photoheterotrophic conditions. Yeast extract (0.1%) and Casamino Acids (1.0%) were found to be antagonistic to the Tris-induced (20 mM) alteration in the phospholipid composition of R. sphaeroides. The wild-type strains R. sphaeroides 2.4.1 and RS2 showed no alteration in their phospholipid composition when they were grown in medium supplemented with Tris. In all strains of Rhodospirillaceae tested, as well as in P. denitrificans, NAPS represented between 1.0 and 2.0% of the total phospholipid when cells were grown in the absence of Tris. [32P]orthophosphoric acid entered NAPS rapidly in strains of R. sphaeroides that do (strain M29-5) and do not (strain 2.4.1) accumulate this phospholipid in response to Tris. Our data indicate that the phospholipid head group composition of many Rhodospirillaceae strains, as well as P. denitrificans, is easily manipulated; thus, these bacteria may provide good model systems for studying the effects of these modifications on membrane structure and function in a relatively unperturbed physiological system.
Effects of nonionic, ionic, and dipolar ionic detergents and EDTA on the Brucella cell envelope
Authors: Moriyon I , Berman D T
Published: June 2021

Cell envelopes prepared from smooth and rough strains of Brucella were characterized on the basis of lipopolysaccharide and protein content. The action of three kinds of detergents on Brucella cell envelopes and Escherichia coli control cell envelopes was examined on the basis of the proteins and lipopolysaccharides that were extracted. As compared with those of E. coli, Brucella cell envelopes were resistant to nonionic detergents. Zwittergents 312 and 316 were most effective in extracting E. coli cell envelopes, and Zwittergent 316 was most effective in extracting Brucella cell envelopes. Sarkosyl extracted proteins but extracted only trace amounts of lipopolysaccharides from cell envelopes of both bacteria. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the Sarkosyl-resistant proteins revealed a composition similar to that of the proteins exposed on the surfaces of viable cells, as determined by the lactoperoxidase-125I radioiodination method. EDTA, with either Tris-HCl or Tris-HCl-Triton X-100, did not have detectable effects on Brucella cell envelopes. Ultracentrifugation of purified lipopolysaccharides in detergents and EDTA demonstrate that, in contrast to that of E. coli, Brucella lipopolysaccharide was not stabilized by divalent cations. Sarkosyl was ineffective in dispersing lipopolysaccharides, whereas the action of Zwittergents was related to the length of their alkyl chains.
Membrane assembly: movement of phosphatidylserine between the cytoplasmic and outer membranes of Escherichia coli
Authors: Langley K E , Hawrot E , Kennedy E P
Published: June 2021

Phosphatidylserine, normally a trace phospholipid in Escherichia coli, accumulates at high levels in temperature-sensitive phosphatidylserine decarboxylase mutants at nonpermissive temperatures. The intracellular localization of this phospholipid has now been determined. All of the accumulated phosphatidylserine is membrane bound and is distributed about equally between the inner and outer membrane fractions of E. coli as determined by isopycnic sucrose gradient fractionation. Phosphatidylserine is therefore effectively translocated from the inner to the outer membrane. Furthermore, this movement is bidirectional. Outer membrane phosphatidylserine can return to the inner membrane, as shown by the complete conversion of accumulated radioactive phosphatidylserine to phosphatidylethanolamine by inner membrane phosphatidylserine decarboxylase during chase periods. Pulse-chase experiments indicated the newly made phosphatidylserine appears first in the inner membrane and then equilibrates between the inner and outer membranes with a half-time of 12 to 13 min.
Activation of chitin synthetase in permeabilized cells of a Saccharomyces cerevisiae mutant lacking proteinase B
Authors: Fernandez M P , Correa J U , Cabib E
Published: June 2021

Digitonin treatment at 30 degrees C of a Saccharomyces cerevisiae mutant lacking proteinase B permeabilized the cells and caused rapid and extensive activation of chitin synthetase in situ. The same result was obtained with a mutant generally defective in vacuolar proteases. By lowering the temperature and using different permeabilization procedures, we showed that increases in permeability and activation are distinct processes. Activation was inhibited by the protease inhibitors antipain and leupeptin, but by pepstatin or chymostatin. Metal chelators were also inhibitory, and their effect was reversed by the addition of Ca2+ but not by Mg2+. Antipain added together with Ca2+ after incubation of the cells in the presence of a chelating agent prevented reversal of inhibition, a result that was interpreted as indicating that antipain acts either on the same step affected by Ca2+ or on a subsequent step. Efforts to obtain activation in cell-free extracts were unsuccessful, but it was possible to extract the synthetase, once activated, by breaking permeabilized cells with glass beads. Treatment of the cell-free extracts with trypsin led not only to increased activity of chitin synthetase, but also to a change in the pH-activity curve and a diminished requirement by the enzyme for free N-acetylglucosamine. These observations suggest that the modification undergone by the synthetase during endogenous activation is different from that brought about by trypsin treatment.
Anaerobic and aerobic urethral flora in healthy females
Authors: Marrie T J , Harding G K , Ronald A R
Published: June 2021

We characterized the aerobic and anaerobic urethral flora of five healthy females by performing urethral and midstream urine cultures once weekly for 8 weeks. Aerobic cultures were performed monthly for an additional 3 months. Lactobacillus spp. were isolated from 52 of 57 samples, Staphylococcus epidermidis from 42 of 57, Corynebacterium spp. from 26 of 57, and alpha-hemolytic streptococci from 14 of 57. Two subjects had E. coli serogroup O6 and group B streptococci isolated on five occasions, respectively. Anaerobes were isolated from 32 of 35 urethral urines (91%). Bacteroides melaninogenicus accounted for 46% of these isolates. The anaerobic urethral flora varied slightly from week to week, and a similar anaerobic flora was isolated from the introitus, fourchette, and cutaneous perineum. In addition, anaerobes were isolated from 16 of 18 healthy females who had a urethral urine sample cultured once only, and B. melaninogenicus was the most frequent isolate. Of the 21 B. melaninogenicus isolates identified to subspecies, 14 were subsp. intermedius.
Plastic multiwell plates to assay avian infectious bronchitis virus in organ cultures of chicken embryo trachea
Authors: Yachida S , Aoyama S , Takahashi N , Iritani Y , Katagiri K
Published: June 2021

Simple assay systems for infectivity titrations of avian infectious bronchitis virus (IBV) in chicken embryo trachea organ cultures (OC) were developed using plastic multiplate wells with one tracheal ring per well; these assays appeared to be much more satisfactory than the conventional rolled-tube method. The medium, 0.05 M HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid)-buffered Eagle minimal essential medium was not changed during observation. A medium containing 0.4% bovine serum albumin did not influence the virus yield, but did stabilize virus viability during storage. Reproducibility of results obtained in the OC system was confirmed by performing replicate titrations of the Beaudette strain with three different passage histories. The mean virus titers in the OC were lower than those in chicken embryos, depending on the IBV passage histories. The time required for ciliostasis was related not only to the concentration of virus, but also to the IBV passage history. Application of OC techniques for the constant serum-variable virus neutralization test gave low neutralization indexes with excellent reproducibility as compared with those obtained in the chicken embryo assay system. Also, the slopes of neutralization curves obtained by assays in OC were less steep than those seen in the chicken embryo system.
Rapid isolation and identification of group B streptococci from selective broth medium by slide co-agglutination test
Authors: Szilagyi G , Mayer E , Eidelman A I
Published: June 2021

Direct identification of group B streptococci from a selective broth medium was performed with the Phadebact streptococcus test to determine the feasibility of this technique for early detection of streptococcal colonization. Of 124 clinical isolates, 122 (98.4%) were correctly identified in less than 24 h from the selective broth medium, whereas standard cultures from blood agar plates identified, after 48 h, only 66 (53.2%). The presence of group B streptococci in mixed cultures was always detected by the Phadebact test, and no false-positive co-agglutination tests were observed in 372 cultures from which organisms other than group B streptococci were isolated.
Precipitate produced by Serratia marcescens on MacConkey agar: useful diagnostic test
Authors: Black W A
Published: June 2021

The production of a precipitate by Serratia marcescens on Oxoid MacConkey agar has proven useful as a laboratory diagnostic test. This phenomenon is specific for Serratia within the Enterobacteriaceae, although precipitate production is also given by Acinetobacter anitratus and some Pseudomonas, Alcaligenes, and Aeromonas species. Precipitate production seems to be specific for certain batches of MacConkey agar, and is probably related to a specific property of some batches of bile salts.
Clostridium pseudotetanicum bacteremia in a patient with Pasteurella multocida conjunctivitis
Authors: Eschete M L , Rambin E D , West B C
Published: June 2021

Clostridium pseudotetanicum only once previously has been identified as causing disease. Pasteurella multocida has been identified only three times as the cause of purulent conjunctivitis. A very debilitated patient had C. pseudotetanicum bacteremia and P. multocida conjunctivitis from which she recovered only to die of a nosocomial Staphylococcus epidermidis septicemia, originating in a site for the administration of intravenous fluids.
Antibody to varicella-zoster virus after passive immunization against chickenpox
Authors: Gershon A A , Piomelli S , Karpatkin M , Smithwick E , Steinberg S
Published: June 2021

Antibody titers to varicella-zoster virus were measured in varicella-susceptible immunocompromised children 48 h after they received either one of two lots of zoster immune globulin (ZIG) or a selected lot of immune serum globulin (ISG). Globulin was given to modify varicella in these children after exposure to varicella or zoster. Indirect immunofluorescence antibody titers (FAMA) of children after receipt of globulin ranged from less than 1:2 to 1:32. Geometric mean FAMA titers were highest after 1.2 ml of ISG per kg (FAMA titer 1:128) and 0.16 ml of ZIG lot A per kg (FAMA titer 1:1,024). Selected batches of ISG titering 1:128 or greater by FAMA, at a dose of 1.2 ml/kg, may be used to attempt to modify varicella in susceptible high-risk individuals when ZIG is not available.
Systematic survey of K, Th, and U signatures in airborne radiometric data from Australian meteorite impact structures: Possible causes of circular features and implications
Authors: Niang* Cheikh Ahmadou Bamba , Baratoux* David , Diallo* Dina Pathé , Rochette* Pierre , Jessell* Mark W. , Reimold* Wolf U. , Bouley* Sylvain , Vanderhaeghe* Olivier , Faye* Gayane , Lambert* Philippe
Published: June 2021

Airborne radiometric (gamma-ray) data provide estimates of the concentrations of potassium (K), thorium (Th), and uranium (U) in soil, regolith, and bedrock. Radiometric data constitute an important source of geochemical information, commonly used in mineral exploration and for geological mapping of Earth and other planets. Airborne radiometric data have rarely been applied to the exploration and analyses of impact structures, in contrast with other conventional geophysical tools (e.g., gravimetry, magnetism, and seismic reflection/refraction). This work represents the first systematic survey of the K, Th, and U radiometric signatures of Australian impact structures, based on the continent-wide airborne radiometric coverage of Australia. We first formulated several hypotheses regarding the possible causes of formation of circular radiometric patterns associated with impact structures. Then, the radiometric signatures of 17 exposed impact structures in Australia were documented. Our observations confirmed the supposition that impact structures are commonly associated with circular radiometric patterns. We then selected the five structures with the most prominent circular radiometric patterns (Gosses Bluff, Lawn Hill, Acraman, Spider, and Shoemaker), and we discuss the possible origin of these anomalies. Based on these five case studies, we argue that such patterns result from either crustal deformation induced by the impact event and/or from postimpact superficial processes controlled by the crater topography. This work also suggests that airborne radiometric data may be useful, in combination with other geophysical tools, in the search for new possible impact structures.
Shock-twinned zircon in ejecta from the 45-m-diameter Kamil crater in southern Egypt
Authors: Cavosie Aaron J. , Folco Luigi
Published: June 2021

With an age of less than ~5000 yr and a diameter of 45 m, Kamil crater in Egypt is one of the youngest and smallest terrestrial impact craters known to date. Abundant evidence of shock-deformed sandstone has been reported from Kamil crater, including shatter cones, vesicular impact glass, high-pressure polymorphs of silica and carbon, planar deformation features (PDFs) and planar fractures (PFs) in quartz, dissociated zircon, melt veins, and intergranular melt, giving rise to a range of estimated shock pressures from ~20 to ~60 GPa. Here, we investigated shocked zircon from Kamil crater through characterization of microstructures in a centimeter-sized clast of shocked nonporous sandstone ejecta, previously described as containing quartz grains with PDFs and PFs, coesite, stishovite, diamond, and lechatelierite. Orientation analysis by electron backscatter diffraction (EBSD) showed that the quartz arenite consists of damaged detrital quartz grains surrounded by a matrix of either comminuted quartz or intergranular melt. Individual quartz grains are pervasively fractured (abundant PFs and PDFs); apparent isotropic crushing resulted in uniformly and highly dispersed orientation clusters on pole figures. Zircon grains are not abundant; however, four of 19 grains analyzed by EBSD contained {112} deformation twin lamellae, with individual lamellae ranging in length from 1 to 2 µm. Lengths of twin lamellae in Kamil zircon grains are anomalously short compared to those reported in shocked zircon from other impact structures, where individual lamellae are tens of micrometers long. Previous empirical studies have suggested that {112} twin lamellae in zircon form at ~20 GPa in non-porous target rocks, a finding supported by their coexistence, in some impactites, with high-pressure phases such as reidite. The only available experimental constraint, by diamond anvil cell, found {112} twins in zircon powder quenched at 20 GPa. The presence of coesite, stishovite, lechatelierite, and shocked quartz with PDFs in the studied sample is consistent with empirically derived pressure estimates of ~20 GPa for {112} twin formation in zircon in the ejecta sample from Kamil crater. Kamil thus represents the smallest and youngest impact structure where shock-twinned zircon has been reported. Given the apparent efficiency of {112} twin formation (21% of grains), shock-twinned zircon is here shown to provide a robust and readily identifiable record of shock deformation in a relatively common mineral at one of the smallest known terrestrial impact craters.
Supplemental Material: A Crucial geologic test of Late Jurassic exotic collision versus endemic re-accretion in the Klamath Mountains Province, western United States, with implications for the assembly of western North America
Authors: LaMaskin Todd A. , al. et
Published: June 2021

Analytical methods, sample collection locations in the southern Klamath Mountains, and Data tables.
Return to work and sick leave patterns following a work injury among young adults: a study protocol of a Swedish multimodal study
Authors: Johansson Malin K , Hasselberg Marie , Rissanen Ritva
Published: June 2021

Introduction

There is a lack of studies that focus exclusively on return to work (RTW) and sick leave patterns following a work injury among young adults. This study aims to close the gap by contributing with knowledge regarding young adults’ sick leave pattern after a work injury and their experience of RTW after a work injury in Sweden.

Methods and analysis

The present study is a multimodal study, which will use Swedish national register data and qualitative data collection by photovoice. Injuries classified as work injuries according to the Swedish injury classification were included. Registry data will be retrieved from the Swedish National-based registers of Swedish Information System on Occupational Accidents and Work-related diseases, the Swedish Social Insurance Agency’s database MicroData for Analysis of Social Insurance and the Swedish Longitudinal Integration Database for Health Insurance and Labour Market Studies. Persons who have registered a work injury at the Swedish Work Environment Authority in 2012 will be included. Sick leave patterns will be analysed using group-based trajectory models and multivariate analyses to explore how sick leave patterns have developed over 5 years. Subsequently, a participatory approach using photovoice method will be conducted to explore young adults’ perceptions of barriers and facilitators in RTW after a work injury. Results from the photovoice group sessions will be analysed using a grounded theoretical approach.

Ethics and dissemination

The study has been reviewed and approved by the Ethical Review Board (case number 2019/028-6) in Sweden. Results of the study will be disseminated through peer-reviewed journals, print and media presentation, conferences and via reports to the funding agency.
Three-month functional outcomes following endovascular thrombectomy during the first wave of the COVID-19 pandemic: a Canadian single-center cohort study
Authors: Neves Briard Joel , Dufort Gabrielle , Jacquin Grégory , Alesefir Walid , Bereznyakova Olena , Boisseau William , Daneault Nicole , Deschaintre Yan , Diestro Jose Danilo Bengzon , Ducroux Célina , Eneling Johanna , Gioia Laura , Iancu Daniela E , Odier Céline , Raymond Jean , Roy Daniel , Stapf Christian , Weill Alain , Poppe Alexandre Y
Published: June 2021

Background

The COVID-19 pandemic has disrupted acute stroke care logistics, including delays in hyperacute management and decreased monitoring following endovascular therapy (EVT). We aimed to assess the impact of the pandemic on 90-day functional outcome among patients treated with EVT.

Methods

This is an observational cohort study including all patients evaluated for an acute stroke between March 30, 2020 and September 30, 2020 (pandemic cohort) and 2019 (reference cohort) in a high-volume Canadian academic stroke center. We collected baseline characteristics, acute reperfusion treatment and management metrics. For EVT-treated patients, we assessed the modified Rankin score (mRS) at 90 days. We evaluated the impact of the pandemic on a 90-day favourable functional status (defined as mRS 0–2) and death using multivariable logistic regressions.

Results

Among 383 and 339 patients included in the pandemic and reference cohorts, baseline characteristics were similar. Delays from symptom onset to evaluation and in-house treatment were longer during the early first wave, but returned to reference values in the subsequent months. Among the 127 and 136 EVT-treated patients in each respective cohort, favourable 90-day outcome occurred in 53/99 (53%) vs 52/109 (48%, p=0.40), whereas 22/99 (22%) and 28/109 (26%, p=0.56) patients died. In multivariable regressions, the pandemic period was not associated with 90-day favourable functional status (aOR 1.27, 95% CI 0.60 to 2.56) or death (aOR 0.74, 95% CI 0.33 to 1.63).

Conclusion

In this single-center cohort study conducted in a Canadian pandemic epicenter, the first 6 months of the COVID-19 pandemic did not impact 90-day functional outcomes or death among EVT-treated patients.
BDNF rescues aging-associated internal anal sphincter dysfunction
Authors: Singh Arjun , Rattan Satish
Published: June 2021

These studies demonstrate that brain-derived neurotropic factor (BDNF) rescues the aging-associated internal anal sphincter (IAS) dysfunction, characterized by a decrease in IAS tone, and increase in non-adrenergic noncholinergic relaxation. We determined the effects of BDNF on the basal and GPCR (TXA2 and ANG II)-stimulated IAS tone, and on NANC relaxation, before and after TrkB inhibitor K252a. BDNF may have an important role in the pathophysiology and therapeutic targeting of certain rectoanal motility disorders.
Contribution of monocarboxylate transporter 12 to blood supply of creatine on the sinusoidal membrane of the hepatocytes
Authors: Jomura Ryuta , Tanno Yu , Akanuma Shin-ichi , Kubo Yoshiyuki , Tachikawa Masanori , Hosoya Ken-ichi
Published: June 2021

Our study is the first to identify the role of monocarboxylate transporter 12 (MCT12) as a transporter of creatine (Cr) in the liver. MCT12 was found to significantly contribute to the efflux of Cr on the sinusoidal membrane of the hepatocytes. Since hepatocytes are known to be involved in creatine biosynthesis. The present findings can be beneficial for the regulation of Cr biosynthesis and supply.