bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of barrier thickness on structural, optical, and spectral behaviors of vertically strain coupled InAs/GaAs quantum dot infrared photodetectors
Authors: Ghadi Hemant , Agarwal Akshay , Adhikary Sourav , Tongbram Binita , Mandal Arjun , Chakrabarti Subhananda , Pendyala Naresh Babu , Prajapati Sachin , Kumar Ashwani
Published: September 2014

The optical, electrical, and spectral properties of a strain coupled InAs quantum dot detector with a fixed quaternary capping of InAlGaAs and variable GaAs barrier thickness were investigated along with an equivalent uncoupled structure. Self-assembled quantum dots with a multimodal dot size distribution were achieved owing to vertical strain coupling. Strain and electronic coupling were utilized to improve the optical and electrical performance of the fabricated quantum dot infrared photodetector. The peak spectral response was tuned by varying barrier thickness, and a blue shift (almost 1 μm) was observed by increasing the capping thickness from sample A (90 Å capping) to E (500 Å capping). High responsivity and detectivity (∼1010 cm Hz1/2/W) were observed for all coupled samples as compared to the uncoupled sample. All coupled samples showed high thermal stability in the photoluminescence peak with high-temperature annealing.
The role of creaky voice in Cantonese tonal perception
Authors: Yu Kristine M. , Lam Hiu Wai
Published: September 2014

There are few studies on the role of phonation cues in the perception of lexical tones in tonal languages where pitch is the primary dimension of contrast. This study shows that listeners are sensitive to creaky phonation in native tonal perception in Cantonese, a language in which the low falling tone, Tone 4, has anecdotally been reported to be sometimes creaky. First, in a multi-speaker corpus of lab speech, it is documented that creak occurs systematically more often on Tone 4 than other tones. Second, for stimuli drawn from this corpus, listeners identified Tone 4 with 20% higher accuracy when it was realized with creak than when it was not. Third, in a two-alternative forced choice task of identifying stimuli as Tone 4 or Tone 6 (the low level tone) isolating creak from any concomitant pitch cues, listeners had a higher proportion of Tone 4 responses for creaky stimuli. Finally, listeners had more Tone 4 responses for creaky stimuli with longer durations of nonmodal phonation. These results underscore that differences in voice quality contribute to human perception of tone alongside f0. Automatic tonal recognition and clinical applications for tone would benefit from attention to voice quality beyond f0 and pitch.
Far-field sound radiation of a submerged cylindrical shell at finite depth from the free surface
Authors: Li T. Y. , Miao Y. Y. , Ye W. B. , Zhu X. , Zhu X. M.
Published: September 2014

The far-field sound radiation behavior of a circular cylindrical shell submerged at finite depth from the free surface is studied. Based on the Flügge shell theory and the Helmholtz equation, the structure-acoustic coupling equation is established. An image method is applied so that the sound boundary condition of the free surface can be satisfied. Analytical expression of the far-field sound pressure is obtained using the stationary phase method and the Graf's addition theorem. In order to evaluate the effect of the submerged depth on sound radiation, the results of the submerged cylindrical shell at finite depth from the free surface are compared with those of the submerged cylindrical shell in the infinite fluid. The characteristics of the far-field sound pressure with the change of the depth are investigated. It is found that the submerged depth has a significant influence on the far-field sound pressure radiated from the submerged cylindrical shell due to the free surface effects. The work provides more understanding on the sound radiation properties of the submerged circular cylindrical shell without assuming infinite fluid field, which was commonly used in previous studies.
Cue-weighting in the perception of intervocalic stop voicing in European Portuguese
Authors: Pape Daniel , Jesus Luis M. T.
Published: September 2014

This paper describes the perception of intervocalic stop voicing in European Portuguese (EP) stimuli without a stop burst, when varying three acoustic cues: Vowel duration, stop duration, and voicing maintenance during stop closure. Perceptual stimuli were generated using biomechanical modeling. First, a discrimination experiment was conducted to determine the listeners' perceptual sensitivity to the voicing maintenance cue. Second, an identification experiment was conducted to examine the effect and interaction of vowel duration, stop duration, and voicing maintenance during stop closure on the voiced/voiceless identification responses of EP listeners. The results of the discrimination test show that voicing maintenance differences have a significant effect as soon as they exceed a certain threshold. In the identification experiment, evidence was found that only the two factors vowel duration and voicing maintenance significantly influence the listeners' decisions, but not stop duration. The ratio between stop duration and vowel duration plays a major role in distinguishing stop voicing, but only for highly devoiced stimuli. It is shown that in stimuli without a stop burst, both voicing maintenance, as a major but not required cue, and vowel duration are important acoustic cues for stop voicing distinctions in EP.
Relationship between multipulse integration and speech recognition with cochlear implants
Authors: Zhou Ning , Pfingst Bryan E.
Published: September 2014

Comparisons of performance with cochlear implants and postmortem conditions in the cochlea in humans have shown mixed results. The limitations in those studies favor the use of within-subject designs and non-invasive measures to estimate cochlear conditions. One non-invasive correlate of cochlear health is multipulse integration, established in an animal model. The present study used this measure to relate neural health in human cochlear implant users to their speech recognition performance. The multipulse-integration slopes were derived based on psychophysical detection thresholds measured for two pulse rates (80 and 640 pulses per second). A within-subject design was used in eight subjects with bilateral implants where the direction and magnitude of ear differences in the multipulse-integration slopes were compared with those of the speech-recognition results. The speech measures included speech reception threshold for sentences and phoneme recognition in noise. The magnitude of ear difference in the integration slopes was significantly correlated with the magnitude of ear difference in speech reception thresholds, consonant recognition in noise, and transmission of place of articulation of consonants. These results suggest that multipulse integration predicts speech recognition in noise and perception of features that use dynamic spectral cues.
Acoustic characterization of monodisperse lipid-coated microbubbles: Relationship between size and shell viscoelastic properties
Authors: Parrales Miguel A. , Fernandez Juan M. , Perez-Saborid Miguel , Kopechek Jonathan A. , Porter Tyrone M.
Published: September 2014

The acoustic attenuation spectrum of lipid-coated microbubble suspensions was measured in order to characterize the linear acoustic behavior of ultrasound contrast agents. For that purpose, microbubbles samples were generated with a very narrow size distribution by using microfluidics techniques. A performance as good as optical characterization techniques of single microbubbles was achieved using this method. Compared to polydispersions (i.e., contrast agents used clinically), monodisperse contrast agents have a narrower attenuation spectrum, which presents a maximum peak at a frequency value corresponding to the average single bubble resonance frequency. The low polydispersity index of the samples made the estimation of the lipid viscoelastic properties more accurate since, as previously reported, the shell linear parameters may change with the equilibrium bubble radius. The results showed the great advantage of dealing with monodisperse populations rather than polydisperse populations for the acoustic characterization of ultrasound contrast agents.
Description and quantification of uncertainty in outdoor sound propagation calculations
Authors: Wilson D. Keith , Pettit Chris L. , Ostashev Vladimir E. , Vecherin Sergey N.
Published: September 2014

The accuracy of outdoor sound propagation predictions is often limited by imperfect knowledge of the atmospheric and ground properties, and random environmental variations such as turbulence. This article describes the impact of such uncertainties, and how they can be efficiently addressed and quantified with stochastic sampling techniques such as Monte Carlo and Latin hypercube sampling (LHS). Extensions to these techniques, such as importance sampling based on simpler, more efficient propagation models, and adaptive importance sampling, are described. A relatively simple example problem involving the Lloyd's mirror effect for an elevated sound source in a homogeneous atmosphere is considered first, followed by a more complicated example involving near-ground sound propagation with refraction and scattering by turbulence. When uncertainties in the atmospheric and ground properties dominate, LHS with importance sampling is found to converge to an accurate estimate with the fewest samples. When random turbulent scattering dominates, the sampling method has little impact. A comprehensive computational approach is demonstrated that is both efficient and accurate, while simultaneously incorporating broadband sources, turbulent scattering, and uncertainty in the environmental properties.
On the wavenumber spectra for sound within subsonic jets
Authors: Agarwal A. , Sinayoko S. , Sandberg R. D.
Published: September 2014

This paper explores the nature of sound spectra within subsonic jets. Three problems of increasing complexity are presented. First, a point source is placed in a two-dimensional plug flow and the sound field is obtained analytically. Second, a point source is embedded in a diverging axisymmetric jet and the sound field is obtained by solving the linearized Euler equations. Finally, an analysis of the acoustic waves propagating through a turbulent jet obtained by direct numerical simulation is presented. In each problem, the pressure or density field is analyzed in the frequency-wavenumber domain. It is found that acoustic waves can be classified into three main frequency-dependent groups. A physical justification is provided for this classification. The main conclusion is that, at low Strouhal numbers, acoustic waves satisfy the d'Alembertian dispersion relation.
Cylindrical acoustical holography applied to full-scale jet noise
Authors: Wall Alan T. , Gee Kent L. , Neilsen Tracianne B. , Krueger David W. , James Michael M.
Published: September 2014

Near-field acoustical holography methods are used to predict sound radiation from an engine installed on a high-performance military fighter aircraft. Cylindrical holography techniques are an efficient approach to measure the large and complex sound fields produced by full-scale jets. It is shown that a ground-based, one-dimensional array of microphones can be used in conjunction with a cylindrical wave function field representation to provide a holographic reconstruction of the radiated sound field at low frequencies. In the current work, partial field decomposition methods and numerical extrapolation of data beyond the boundaries of the hologram aperture are required prior to holographic projection. Predicted jet noise source distributions and directionality are shown for four frequencies between 63 and 250 Hz. It is shown that the source distribution narrows and moves upstream, and that radiation directionality shifts toward the forward direction, with increasing frequency. A double-lobe feature of full-scale jet radiation is also demonstrated.
Perceptual learning of temporally interrupted spectrally degraded speech
Authors: Benard Michel Ruben , Başkent Deniz
Published: September 2014

Normal-hearing (NH) listeners make use of context, speech redundancy and top-down linguistic processes to perceptually restore inaudible or masked portions of speech. Previous research has shown poorer perception and restoration of interrupted speech in CI users and NH listeners tested with acoustic simulations of CIs. Three hypotheses were investigated: (1) training with CI simulations of interrupted sentences can teach listeners to use the high-level restoration mechanisms more effectively, (2) phonemic restoration benefit, an increase in intelligibility of interrupted sentences once its silent gaps are filled with noise, can be induced with training, and (3) perceptual learning of interrupted sentences can be reflected in clinical speech audiometry. To test these hypotheses, NH listeners were trained using periodically interrupted sentences, also spectrally degraded with a noiseband vocoder as CI simulation. Feedback was presented by displaying the sentence text and playing back both the intact and the interrupted CI simulation of the sentence. Training induced no phonemic restoration benefit, and learning was not transferred to speech audiometry measured with words. However, a significant improvement was observed in overall intelligibility of interrupted spectrally degraded sentences, with or without filler noise, suggesting possibly better use of restoration mechanisms as a result of training.
Using simple shape three-dimensional rigid inclusions to enhance porous layer absorption
Authors: Groby J.-P. , Lagarrigue C. , Brouard B. , Dazel O. , Tournat V. , Nennig B.
Published: September 2014

The absorption properties of a metaporous material made of non-resonant simple shape three-dimensional rigid inclusions (cube, cylinder, sphere, cone, and ring torus) embedded in a rigidly backed rigid-frame porous material are studied. A nearly total absorption can be obtained for a frequency lower than the quarter-wavelength resonance frequency due to the excitation of a trapped mode. To be correctly excited, this mode requires a filling fraction larger in three-dimensions than in two-dimensions for purely convex (cube, cylinder, sphere, and cone) shapes. At long wavelengths compared to the spatial period, a cube is found to be the best purely convex inclusion shape to embed in a cubic unit cell, while the embedment of a sphere or a cone cannot lead to an optimal absorption for some porous material properties and dimensions of the unit cell. At a fixed position of purely convex shape inclusion barycenter, the absorption coefficient only depends on the filling fraction and does not depend on the shape below the Bragg frequency arising from the interaction between the inclusion and its image with respect to the rigid backing. The influence of the incidence angle and of the material properties, namely, the flow resistivity is also shown. The results of the modeling are validated experimentally in the case of cubic and cylindrical inclusions.
Spatial hearing benefits demonstrated with presentation of acoustic temporal fine structure cues in bilateral cochlear implant listeners
Authors: Churchill Tyler H. , Kan Alan , Goupell Matthew J. , Litovsky Ruth Y.
Published: September 2014

Most contemporary cochlear implant (CI) processing strategies discard acoustic temporal fine structure (TFS) information, and this may contribute to the observed deficits in bilateral CI listeners' ability to localize sounds when compared to normal hearing listeners. Additionally, for best speech envelope representation, most contemporary speech processing strategies use high-rate carriers (≥900 Hz) that exceed the limit for interaural pulse timing to provide useful binaural information. Many bilateral CI listeners are sensitive to interaural time differences (ITDs) in low-rate (<300 Hz) constant-amplitude pulse trains. This study explored the trade-off between superior speech temporal envelope representation with high-rate carriers and binaural pulse timing sensitivity with low-rate carriers. The effects of carrier pulse rate and pulse timing on ITD discrimination, ITD lateralization, and speech recognition in quiet were examined in eight bilateral CI listeners. Stimuli consisted of speech tokens processed at different electrical stimulation rates, and pulse timings that either preserved or did not preserve acoustic TFS cues. Results showed that CI listeners were able to use low-rate pulse timing cues derived from acoustic TFS when presented redundantly on multiple electrodes for ITD discrimination and lateralization of speech stimuli.
Comparison of predictive measures of speech recognition after noise reduction processing
Authors: Smeds Karolina , Leijon Arne , Wolters Florian , Hammarstedt Anders , Båsjö Sara , Hertzman Sofia
Published: September 2014

A number of measures were evaluated with regard to their ability to predict the speech-recognition benefit of single-channel noise reduction (NR) processing. Three NR algorithms and a reference condition were used in the evaluation. Twenty listeners with impaired hearing and ten listeners with normal hearing participated in a blinded laboratory study. An adaptive speech test was used. The speech test produces results in terms of signal-to-noise ratios that correspond to equal speech recognition performance (in this case 80% correct) with and without the NR algorithms. This facilitates a direct comparison between predicted and experimentally measured effects of noise reduction algorithms on speech recognition. The experimental results were used to evaluate nine different predictive measures, one in two variants. The best predictions were found with the Coherence Speech Intelligibility Index (CSII) [Kates and Arehart (2005), J. Acoust. Soc. Am. 117(4), 2224–2237]. In general, measures using correlation between the clean speech and the processed noisy speech, as well as other measures that are based on short-time analysis of speech and noise, seemed most promising
Perception and automatic detection of wind-induced microphone noise
Authors: Jackson Iain R. , Kendrick Paul , Cox Trevor J. , Fazenda Bruno M. , Li Francis F.
Published: September 2014

Wind can induce noise on microphones, causing problems for users of hearing aids and for those making recordings outdoors. Perceptual tests in the laboratory and via the Internet were carried out to understand what features of wind noise are important to the perceived audio quality of speech recordings. The average A-weighted sound pressure level of the wind noise was found to dominate the perceived degradation of quality, while gustiness was mostly unimportant. Large degradations in quality were observed when the signal to noise ratio was lower than about 15 dB. A model to allow an estimation of wind noise level was developed using an ensemble of decision trees. The model was designed to work with a single microphone in the presence of a variety of foreground sounds. The model outputted four classes of wind noise: none, low, medium, and high. Wind free examples were accurately identified in 79% of cases. For the three classes with noise present, on average 93% of samples were correctly assigned. A second ensemble of decision trees was used to estimate the signal to noise ratio and thereby infer the perceived degradation caused by wind noise.
Observation of thermoacoustic shock waves in a resonance tube
Authors: Biwa Tetsushi , Sobata Kazuya , Otake Shota , Yazaki Taichi
Published: September 2014

This paper reports thermally induced shock waves observed in an acoustic resonance tube. Self-sustained oscillations of a gas column were created by imposing an axial temperature gradient on the short stack of plates installed in the resonance tube filled with air at atmospheric pressure. The tube length and axial position of the stack were examined so as to make the acoustic amplitude of the gas oscillations maximum. The periodic shock wave was observed when the acoustic pressure amplitude reached 8.3 kPa at the fundamental frequency. Measurements of the acoustic intensity show that the energy absorption in the stack region with the temperature gradient tends to prevent the nonlinear excitation of harmonic oscillations, which explains why the shock waves had been unfavorable in the resonance tube thermoacoustic systems.
Root finding in the complex plane for seismo-acoustic propagation scenarios with Green's function solutions
Authors: McCollom Brittany A. , Collis Jon M.
Published: September 2014

A normal mode solution to the ocean acoustic problem of the Pekeris waveguide with an elastic bottom using a Green's function formulation for a compressional wave point source is considered. Analytic solutions to these types of waveguide propagation problems are strongly dependent on the eigenvalues of the problem; these eigenvalues represent horizontal wavenumbers, corresponding to propagating modes of energy. The eigenvalues arise as singularities in the inverse Hankel transform integral and are specified by roots to a characteristic equation. These roots manifest themselves as poles in the inverse transform integral and can be both subtle and difficult to determine. Following methods previously developed [S. Ivansson et al., J. Sound Vib. 161 (1993)], a root finding routine has been implemented using the argument principle. Using the roots to the characteristic equation in the Green's function formulation, full-field solutions are calculated for scenarios where an acoustic source lies in either the water column or elastic half space. Solutions are benchmarked against laboratory data and existing numerical solutions.
Frequency of greatest temporary hearing threshold shift in harbor porpoises (Phocoena phocoena) depends on the noise level
Authors: Kastelein Ronald A. , Schop Jessica , Gransier Robin , Hoek Lean
Published: September 2014

Harbor porpoises may suffer hearing loss when they are exposed to high level sounds. After exposure for 60 min to a 6.5 kHz continuous tone at average received sound pressure levels (SPLav.re.) ranging from 118 to 154 dB re 1μPa, the temporary hearing threshold shifts (TTSs) of a harbor porpoise were quantified at the center frequency (6.5 kHz), at 0.5, 1.0, and 1.3 octaves above the center frequency (9.2, 13.0, and 16.0 kHz), and at a frequency assumed to be ecologically important for harbor porpoises (125 kHz, the center frequency of their echolocation signals) by means of a psychoacoustic technique. The hearing frequency at which the maximum TTS occurred depended on the SPLav.re. The higher the SPLav.re., the higher the TTS induced at frequencies higher than the exposure frequency; below 148 dB re 1 μPa, the maximum TTS was at 6.5 kHz, whereas above 148 dB re 1 μPa, the maximum TTS was at 9.2 kHz. The hearing threshold of the harbor porpoise for the center frequency of its echolocation signals (125 kHz) was not affected at the highest SPLav.re. to which the animal was exposed.
An acoustic double fishnet using Helmholtz resonators
Authors: Murray A. R. J. , Summers I. R. , Sambles J. R. , Hibbins A. P.
Published: September 2014

The acoustic transmission of a closely spaced pair of patterned and perforated rigid plates is explored in air. The structure resembles an acoustic double fishnet design, with each plate modified such that the gap between them acts as an array of Helmholtz resonators. This allows the center frequency of the stop band to be reduced by a factor greater than 2 from the value obtained for the conventional acoustic double fishnet design. Experimental results accord well with the predictions of a finite element model.
Analytical coupled vibroacoustic modeling of membrane-type acoustic metamaterials: Membrane model
Authors: Chen Yangyang , Huang Guoliang , Zhou Xiaoming , Hu Gengkai , Sun Chin-Teh
Published: September 2014

Membrane-type acoustic metamaterials (MAMs) have demonstrated unusual capacity in controlling low-frequency sound transmission/reflection. In this paper, an analytical vibroacoustic membrane model is developed to study sound transmission behavior of the MAM under a normal incidence. The MAM is composed of a prestretched elastic membrane with attached rigid masses. To accurately capture finite-dimension rigid mass effects on the membrane deformation, the point matching approach is adopted by applying a set of distributed point forces along the interfacial boundary between masses and the membrane. The accuracy and capability of the theoretical model is verified through the comparison with the finite element method. In particular, microstructure effects such as weight, size, and eccentricity of the attached mass, pretension, and thickness of the membrane on the resulting transmission peak and dip frequencies of the MAM are quantitatively investigated. New peak and dip frequencies are found for the MAM with one and multiple eccentric attached masses. The developed model can be served as an efficient tool for design of such membrane-type metamaterials.
A systematic rationale for defining the significance of aircraft noise impacts
Authors: Fidell Sanford , Mestre Vincent , Schomer Paul , Horonjeff Richard , Reid Tim
Published: September 2014

Regulatory agencies often define strict, decibel-denominated thresholds of significance of noise impacts to protect some fraction of the residential population from exposure to highly annoying noise. Definitions of the “significance” of aircraft noise impacts and recommendations of land use “compatibility,” however, typically lack detailed, systematic rationales. Instead, the definitions are justified by reference to decades-old policies that were adopted without benefit of modern understandings of noise-induced annoyance, by appeals to authority, and by generic citations of non-peer reviewed documents. Although regulatory policy decisions may properly take into consideration political and economic consequences, aspects of them are amenable to logical formalization. In particular, advances in understanding of community reaction to transportation noise now permit a systematic rationale for aircraft noise regulation. The current analyses show how regulatory policy positions can be derived from two parameters: (1) the minimal percentage of the population of a nominally average community to be protected from exposure to highly annoying noise; and (2) the percentage of all communities to which this degree of protection is intended to apply. Together with a reliable dosage-response relationship, these two parameters permit quantitatively justifiable definitions of significant noise impact.
ACOUSTICAL STANDARDS NEWS
Authors: Blaeser Susan B. , Schomer Paul D.
Published: September 2014

American National Standards (ANSI Standards) developed by Accredited Standards Committees S1, S2, S3, S3/SC 1, and S12 in the areas of acoustics, mechanical vibration and shock, bioacoustics, animal bioacoustics, and noise, respectively, are published by the Acoustical Society of America (ASA). In addition to these standards, ASA publishes catalogs of Acoustical Standards, both National and International. To receive copies of the latest Standards catalogs, please contact Susan B. Blaeser.

Comments are welcomed on all material in Acoustical Standards News.

This Acoustical Standards News section in JASA, as well as the National and International Catalogs of Acoustical Standards, and other information on the Standards Program of the Acoustical Society of America, are available via the ASA home page: http://acousticalsociety.org.
The Effects of Message Appeal on Consumer Attitude Toward Sporting Events
Authors: Jang Wonseok , Ko Yong Jae , Stepchenkova Svetlana
Published: September 2014

Advertisers put considerable effort into developing messages that appeal to a persuadable target group. Based on the characteristics of these audiences, as well as a number of situational factors, advertising messages can be described as primarily informational or emotional. The purpose of this study was to test how the value orientation of a sports-related event and situational involvement moderate consumers’ information processing and attitudes toward the event advertisement. Consistent with dual-process theory, the results indicate that, when dealing with information about a utilitarian sports career-fair event, consumers rely on either effortful or effortless processing depending on their level of situational involvement. However, consumers use both effortful and effortless processing for a hedonic sporting event. This study extends the dual-process theory and planning models by suggesting that a traditional, theory-based dichotomous dual-process model should give way to a co-occurrence model for hedonic sporting events in high-involvement situations.
Pinterest and Female Sport Fans: Gaining a Foothold in the Male-Dominated Sport World
Authors: Conlin Lindsey , McLemore Dylan M. , Rush Richard A.
Published: September 2014

Female sport fans account for over 45% of the fan base in some major professional sport leagues. This study analyzes every verified Pinterest account from teams in the 4 major North American sport leagues to investigate how teams use a social network consisting largely of female users to reach this growing target audience. The study finds that sport teams use Pinterest to promote purchasable items, share information about the team, highlight the fan experience, and share creative content—although to a lesser extent than the typical Pinterest user. Differences between leagues and details of content frames are discussed. Future directives for understanding how sport teams use Pinterest are presented, and the utility of visual framing for investigating new media is discussed.
Sport Communication: A Multidimensional Assessment of the Field’s Development
Authors: Abeza Gashaw , O’Reilly Norm , Nadeau John
Published: September 2014

Sport and communication have existed since humans began interacting with one another, with organized sport and planned communication formalized for hundreds of years. However, social science scholars have only taken a high-level of interest in sport communication over the past decade. Over the past 10 years, much has been written and researched in the field, and its formalization continues, justifying a need for a review of its current status and the articulation of its future directions. Thus, this article identifies and critically discusses the developments in the field of sport communication in terms of its academic infrastructures and the resulting body of knowledge. It also assesses how the field’s developments are affecting scholarly advancements and identifies areas of “disciplinary pain.” The work concludes by providing suggestions for future research.
Breaking Down Translation Barriers: Investigator’s Perspective
Authors: Staff Nathan P. , Runge Bethany Kinseth , Windebank Anthony J.
Published: September 2014

Biomedical scientists can exploit initiatives from U.S. federal regulatory and funding agencies aimed at accelerating clinical translation.
Breast-fed and bottle-fed infant rhesus macaques develop distinct gut microbiotas and immune systems
Authors: Ardeshir Amir , Narayan Nicole R. , Méndez-Lagares Gema , Lu Ding , Rauch Marcus , Huang Yong , Van Rompay Koen K. A. , Lynch Susan V. , Hartigan-O’Connor Dennis J.
Published: September 2014

Breast-feeding and bottle-feeding promote different gut microbial communities, which are associated with development of different immune systems in rhesus macaque infants.
A therapeutically targetable mechanism of BCR-ABL–independent imatinib resistance in chronic myeloid leukemia
Authors: Ma Leyuan , Shan Yi , Bai Robert , Xue Liting , Eide Christopher A. , Ou Jianhong , Zhu Lihua J. , Hutchinson Lloyd , Cerny Jan , Khoury Hanna Jean , Sheng Zhi , Druker Brian J. , Li Shaoguang , Green Michael R.
Published: September 2014

A large-scale RNA interference screen reveals a new mechanism of imatinib resistance in chronic myeloid leukemia that can be therapeutically targeted.
Effective diagnosis of genetic disease by computational phenotype analysis of the disease-associated genome
Authors: Zemojtel Tomasz , Köhler Sebastian , Mackenroth Luisa , Jäger Marten , Hecht Jochen , Krawitz Peter , Graul-Neumann Luitgard , Doelken Sandra , Ehmke Nadja , Spielmann Malte , Øien Nancy Christine , Schweiger Michal R. , Krüger Ulrike , Frommer Götz , Fischer Björn , Kornak Uwe , Flöttmann Ricarda , Ardeshirdavani Amin , Moreau Yves , Lewis Suzanna E. , Haendel Melissa , Smedley Damian , Horn Denise , Mundlos Stefan , Robinson Peter N.
Published: September 2014

Patients with genetic disease of unknown causes can be rapidly diagnosed by bioinformatic analysis of disease-associated DNA sequences and phenotype.
Prostate cancer cell–stromal cell crosstalk via FGFR1 mediates antitumor activity of dovitinib in bone metastases
Authors: Wan Xinhai , Corn Paul G. , Yang Jun , Palanisamy Nallasivam , Starbuck Michael W. , Efstathiou Eleni , Li Ning Tapia Elsa M. , Zurita Amado J. , Aparicio Ana , Ravoori Murali K. , Vazquez Elba S. , Robinson Dan R. , Wu Yi-Mi , Cao Xuhong , Iyer Matthew K. , McKeehan Wallace , Kundra Vikas , Wang Fen , Troncoso Patricia , Chinnaiyan Arul M. , Logothetis Christopher J. , Navone Nora M.
Published: September 2014

Dovitinib is therapeutically active in a subset of patients with prostate cancer bone metastases, partly due to blockade of FGFR-mediated stromal-epithelial interactions in the bone microenvironment.
Traumatic Brain Injury: Lungs in a RAGE
Authors: Nicolls Mark R. , Laubach Victor E.
Published: September 2014

Individuals who die of traumatic brain injury show damage to the lungs mediated by the HMGB1-RAGE axis, which renders the lungs suboptimal for transplantation (Weber
et al
.).
Old-Age Interfer(on)ing
Authors: Schaefer Anne
Published: September 2014

Age-dependent cognitive decline is linked to an increased interferon response in

brain–circulatory system interface.
Window of Opportunity
Authors: Stephan Matthias
Published: September 2014

Carbon nanotubes along with new medical imaging tools provide a clear view of blood flow in the brain.
The Microbial Origins of Obesity
Authors: Tsalik Ephraim L.
Published: September 2014

Disrupting the early-life gut microbiota induces lasting and transmissible metabolic changes.
Comprehensive Analysis and Selection of Anthrax Vaccine Adsorbed Immune Correlates of Protection in Rhesus Macaques
Authors: Chen Ligong , Schiffer Jarad M. , Dalton Shannon , Sabourin Carol L. , Niemuth Nancy A. , Plikaytis Brian D. , Quinn Conrad P.
Published: September 2014

Humoral and cell-mediated immune correlates of protection (COP) for inhalation anthrax in a rhesus macaque (Macaca mulatta) model were determined. The immunological and survival data were from 114 vaccinated and 23 control animals exposed toBacillus anthracisspores at 12, 30, or 52 months after the first vaccination. The vaccinated animals received a 3-dose intramuscular priming series (3-i.m.) of anthrax vaccine adsorbed (AVA) (BioThrax) at 0, 1, and 6 months. The immune responses were modulated by administering a range of vaccine dilutions. Together with the vaccine dilution dose and interval between the first vaccination and challenge, each of 80 immune response variables to anthrax toxin protective antigen (PA) at every available study time point was analyzed as a potential COP by logistic regression penalized by least absolute shrinkage and selection operator (LASSO) or elastic net. The anti-PA IgG level at the last available time point before challenge (last) and lymphocyte stimulation index (SI) at months 2 and 6 were identified consistently as a COP. Anti-PA IgG levels and lethal toxin neutralization activity (TNA) at months 6 and 7 (peak) and the frequency of gamma interferon (IFN-γ)-secreting cells at month 6 also had statistically significant positive correlations with survival. The ratio of interleukin 4 (IL-4) mRNA to IFN-γ mRNA at month 6 also had a statistically significant negative correlation with survival. TNA had lower accuracy as a COP than did anti-PA IgG response. Following the 3-i.m. priming with AVA, the anti-PA IgG responses at the time of exposure or at month 7 were practicable and accurate metrics for correlating vaccine-induced immunity with protection against inhalation anthrax.
Heterogeneity in Rhesus Macaque Complement Factor H Binding to Meningococcal Factor H Binding Protein (FHbp) Informs Selection of Primates To Assess Immunogenicity of FHbp-Based Vaccines
Authors: Beernink Peter T. , Shaughnessy Jutamas , Stefek Heather , Ram Sanjay , Granoff Dan M.
Published: September 2014

Neisseria meningitidiscauses disease only in humans. An important mechanism underlying this host specificity is the ability of the organism to resist complement by recruiting the complement downregulator factor H (FH) to the bacterial surface. In previous studies, binding of FH to one of the major meningococcal FH ligands, factor H binding protein (FHbp), was reported to be specific for human FH. Here we report that sera from 23 of 73 rhesus macaques (32%) tested had high FH binding to FHbp. Similar to human FH, binding of macaque FH to the meningococcal cell surface inhibited the complement alternative pathway by decreasing deposition of C3b. FH contains 20 domains (or short consensus repeats), with domains 6 and 7 being responsible for binding of human FH to FHbp. DNA sequence analyses of FH domains 6 and 7 from macaques with high or low FH binding showed a polymorphism at residue 352 in domain 6, with Tyr being associated with high binding and His with low binding. A recombinant macaque FH 6,7/Fc fragment with Tyr352 showed higher binding to FHbp than the corresponding fragment with His352. In previous studies in human FH transgenic mice, binding of FH to FHbp vaccines decreased protective antibody responses, and mutant FHbp vaccines with decreased FH binding elicited serum antibodies with greater protective activity. Thus, macaques with high FH binding to FHbp represent an attractive nonhuman primate model to investigate further the effects of FH binding on the immunogenicity of FHbp vaccines.
Antibody Response to a T-Cell-Independent Antigen Is Preserved after Splenic Artery Embolization for Trauma
Authors: Olthof D. C. , Lammers A. J. J. , van Leeuwen E. M. M. , Hoekstra J. B. L. , ten Berge I. J. M. , Goslings J. C.
Published: September 2014

Splenic artery embolization (SAE) is increasingly being used as a nonoperative management strategy for patients with blunt splenic injury following trauma. The aim of this study was to assess the splenic function of patients who were embolized. A clinical study was performed, with splenic function assessed by examining the antibody response to polysaccharide antigens (pneumococcal 23-valent polysaccharide vaccine), B-cell subsets, and the presence of Howell-Jolly bodies (HJB). The data were compared to those obtained from splenectomized patients and healthy controls (HC) who had been included in a previously conducted study. A total of 30 patients were studied: 5 who had proximal SAE, 7 who had distal SAE, 8 who had a splenectomy, and 10 HC. The median vaccine-specific antibody response of the SAE patients (fold increase, 3.97) did not differ significantly from that of the HC (5.29;P= 0.90); however, the median response of the splenectomized patients (2.30) did differ (P= 0.003). In 2 of the proximally embolized patients and none of the distally embolized patients, the ratio of the IgG antibody level postvaccination compared to that prevaccination was <2. There were no significant differences in the absolute numbers of lymphocytes or B-cell subsets between the SAE patients and the HC. HJB were not observed in the SAE patients. The splenic immune function of embolized patients was preserved, and therefore routine vaccination appears not to be indicated. Although the median antibody responses did not differ between the patients who underwent proximal SAE and those who underwent distal SAE, 2 of the 5 proximally embolized patients had insufficient responses to vaccination, whereas none of the distally embolized patients exhibited an insufficient response. Further research should be done to confirm this finding.
Molecular and Phenotypic Characterization of Vibrio navarrensis Isolates Associated with Human Illness
Authors: Gladney Lori M. , Tarr Cheryl L.
Published: September 2014

We characterized 18
Vibrio
isolates, including 15 recovered from human clinical specimens, and found that they clustered with two previously characterized
Vibrio navarrensis
isolates in a phylogenetic analysis. Four of the 18 strains may represent a new
Vibrio
species, distinct from
V. navarrensis
. The potential role of
V. navarrensis
in human disease needs further investigation.
First Reported Case of Ehrlichia ewingii Involving Human Bone Marrow
Authors: Allen M. Brandon , Pritt Bobbi S. , Sloan Lynne M. , Paddock Christopher D. , Musham Chaitanya K. , Ramos Jeanette M. , Cetin Neslihan , Rosenbaum Eric R.
Published: September 2014

A 65-year-old female with a history of multiple tick bites presented with fever and pancytopenia. Intracytoplasmic rickettsial morulae were detected on peripheral smear and bone marrow biopsy specimens, and PCR amplified
Ehrlichia ewingii
DNA from both specimens. To our knowledge, this is the first report of
E. ewingii
infection of human bone marrow.
Seroepidemiologic Study of Human Infections with Spotted Fever Group Rickettsiae in North Carolina
Authors: Vaughn Meagan F. , Delisle Josie , Johnson Joey , Daves Gaylen , Williams Carl , Reber Jodi , Mendell Nicole L. , Bouyer Donald H. , Nicholson William L. , Moncayo Abelardo C. , Meshnick Steven R.
Published: September 2014

Increasing entomologic and epidemiologic evidence suggests that spotted fever group rickettsiae (SFGR) other than
Rickettsia rickettsii
are responsible for spotted fever rickettsioses in the United States. A retrospective seroepidemiologic study was conducted on stored acute- and convalescent-phase sera that had been submitted for Rocky Mountain spotted fever testing to the North Carolina State Laboratory of Public Health. We evaluated the serologic reactivity of the paired sera to
R. rickettsii
,
Rickettsia parkeri
, and
Rickettsia amblyommii
antigens. Of the 106 eligible pairs tested, 21 patients seroconverted to one or more antigens. Cross-reactivity to multiple antigens was observed in 10 patients, and seroconversions to single antigens occurred in 11 patients, including 1 against
R. rickettsii
, 4 against
R. parkeri
, and 6 against
R. amblyommii
. Cross-absorption of cross-reactive sera and/or Western blots identified two presumptive cases of infection with
R. parkeri
, two presumptive cases of infection with
R. rickettsii
, and one presumptive case of infection with
R. amblyommii
. These findings suggest that species of SFGR other than
R. rickettsii
are associated with illness among North Carolina residents and that serologic testing using
R. rickettsii
antigen may miss cases of spotted fever rickettsioses caused by other species of SFGR.
Improved Single-Copy Assays for Quantification of Persistent HIV-1 Viremia in Patients on Suppressive Antiretroviral Therapy
Authors: Cillo Anthony R. , Vagratian David , Bedison Margaret A. , Anderson Elizabeth M. , Kearney Mary F. , Fyne Elizabeth , Koontz Dianna , Coffin John M. , Piatak Michael , Mellors John W.
Published: September 2014

A quantitative real-time PCR (qRT-PCR) assay with single-copy sensitivity targeting HIV-1
gag
RNA (the
gag
single-copy assay [gSCA]) has been used widely to quantify plasma viremia below the limit of detection of clinical assays in patients on effective antiretroviral therapy (ART), but viral RNA in 15 to 30% of samples amplifies inefficiently because of primer/probe mismatches. We sought to develop improved single-copy assays with increased sensitivity by improving nucleic acid recovery, designing qRT-PCR primers and a probe for a highly conserved region of integrase in the HIV-1
pol
gene (the integrase single-copy assay [iSCA]), and increasing the plasma volume tested (Mega-iSCA). We evaluated gSCA versus iSCA in paired plasma samples from 10 consecutive patients with viremia of >1,000 copies/ml and 25 consecutive patients on suppressive ART. Three of 10 viremic samples amplified inefficiently with gSCA compared to the Roche Cobas Ampliprep/TaqMan 2.0, whereas all 10 samples amplified efficiently with iSCA. Among 25 samples from patients on suppressive ART, 8 of 12 samples that were negative for HIV-1 RNA by gSCA had detectable HIV-1 RNA by iSCA, and iSCA detected 3-fold or higher HIV-1 RNA levels compared to gSCA in 10 of 25 samples. Large-volume plasma samples (>20 ml) from 7 patients were assayed using Mega-iSCA, and HIV-1 RNA was quantifiable in 6, including 4 of 5 that were negative by standard-volume iSCA. These improved assays with superior sensitivity will be useful for evaluating whether
in vivo
interventions can reduce plasma viremia and for assessing relationships between residual viremia and other virologic parameters, including the inducible proviral reservoir.
Phenotypic Detection of Carbapenemase-Producing Enterobacteriaceae by Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and the Carba NP Test
Authors: Knox James , Jadhav Snehal , Sevior Danielle , Agyekum Alex , Whipp Margaret , Waring Lynette , Iredell Jonathan , Palombo Enzo
Published: September 2014

We compared the diagnostic accuracy of the Carba NP test with that of a straightforward matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) method for detecting carbapenemase-producing
Enterobacteriaceae
(CPE). Using PCR as the reference method, both tests demonstrated a sensitivity of 87% and a specificity of 100%. MALDI-TOF MS offers a potential alternative for the rapid detection of CPE in the clinical laboratory setting.