bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinicopathological findings of canine seborrhoeic keratosis with comparison to pigmented viral plaques
Authors: Bradley Charles W. , Luff Jennifer A. , Mauldin Elizabeth A.
Published: June 2013

Background

Seborrhoeic keratoses (SKs) are common benign epidermal neoplasms in humans and are rarely diagnosed in the dog. These circumscribed, raised, variably pigmented plaques arise in middle aged to older humans, with a focal or multicentric distribution; although common, the underlying cause of these lesions is not known. Although less common in the dog, the lesions are similar and have features that overlap with papillomavirus‐associated pigmented viral plaques.

Hypothesis/Objectives

Seborrhoeic keratoses in the dog are negative for canine papillomavirus.

Animals

Eleven cases of SK from a 12 year period were reviewed.

Methods

This was a retrospective study of the histopathological findings and case histories. Complete clinical records following collection of the skin biopsy were available in five of 11 cases. Immunohistochemistry was performed for all cases; PCR analysis was carried out for papillomavirus in six cases.

Results

Histologically, SKs had an exophytic to mildly endophytic epidermal proliferation, creating a papillomatous to acanthotic, hyperkeratotic, frequently pigmented plaque. There was an absence of hypergranulosis or viral cytopathic effect; PCRs for canine papillomavirus within the formalin‐fixed paraffin‐embedded skin biopsies were negative. No breed, sex or site predilection was recognized. The mean age at biopsy of the lesions was 8.8 years (range 5–14 years).

Conclusions and clinical importance

Histopathological features and negative papillomavirus status distinguish SK as an important differential diagnosis for pigmented viral plaques in dogs.
Measurement of cortisol in dog hair: a noninvasive tool for the diagnosis of hypercortisolism
Authors: Ouschan Claudia , Kuchar Alexandra , Möstl Erich
Published: June 2013

Background

The clinical signs of hyperadrenocorticism (hypercortisolism) in dogs are known to be caused by chronic overexposure to glucocorticoids. The quantification of cortisol in serum, saliva or urine reflects the cortisol concentration at the time of sample collection, but in suspected hyperadrenocorticism it may be preferable to examine a long‐term parameter of cortisol production.

Hypothesis/Objectives

There is a need for a noninvasive method to monitor the long‐term production of cortisol in dogs. It seems possible that measuring cortisol levels in hair could represent such a method.

Animals

Hair was collected from 12 dogs with hyperadrenocorticism and from 10 healthy control dogs.

Methods

Immunoreactive cortisol, cortisone and corticosterone concentrations were determined by enzyme immunoassay. High‐performance liquid chromatography was performed to test the validity of the cortisol assay.

Results

Levels of immunoreactive cortisol, cortisone and corticosterone were significantly higher in dogs with hyperadrenocorticism than in control dogs. The difference was most pronounced for the cortisol level.

Conclusions and clinical importance

The determination of cortisol in hair offers the advantage that sampling is easier and less invasive than taking blood, urine, faeces or saliva. Measuring cortisol in hair may represent a valuable tool for the diagnosis of hyperadrenocorticism in dogs.
Flow-Rate Observers in the Suppression of Compressor Surge Using Active Magnetic Bearings
Authors: Yoon Se Young , Lin Zongli , Jiang Wei , Allaire Paul E.
Published: June 2013

Surge is a dynamic flow instability that can cause extensive damage to compressors and other components. One common challenge that many surge control methods in the literature face when implemented in industrial applications is the unavailability of the high performance actuators and accurate flow rate measurements that are required to suppress surge. In this paper we present the experimental results of employing active magnetic bearings in order to suppress the surge instability in a centrifugal compressor. In addition, we compare how the selection of the flow estimation method affects the effectiveness of the implemented surge suppression controller. The experimental data demonstrates that the best combination of controller and flow estimator tested in this work allows the compressor to operate deep into the former surge region when the controller is activated, moving the minimum flow rate at the surge initiation point by 21%. This allows the compression system to operate at the highest efficiency/pressure point in the characteristic curve, while still retaining a very conservative surge margin separating the allowed compressor operating region from the surge inception point even if unexpected system changes occur.
Fundamental radiological and geometric performance of two types of proton beam modulated discrete scanning systems
Authors: Farr J. B. , Dessy F. , De Wilde O. , Bietzer O. , Schönenberg D.
Published: June 2013

Purpose:

The purpose of this investigation was to compare and contrast the measured fundamental properties of two new types of modulated proton scanning systems. This provides a basis for clinical expectations based on the scanned beam quality and a benchmark for computational models. Because the relatively small beam and fast scanning gave challenges to the characterization, a secondary purpose was to develop and apply new approaches where necessary to do so.

Methods:

The following performances of the proton scanning systems were investigated: beamlet alignment, static in‐air beamlet size and shape, scanned in‐air penumbra, scanned fluence map accuracy, geometric alignment of scanning system to isocenter, maximum field size, lateral and longitudinal field uniformity of a 1 l cubic uniform field, output stability over time, gantry angle invariance, monitoring system linearity, and reproducibility. A range of detectors was used: film, ionization chambers, lateral multielement and longitudinal multilayer ionization chambers, and a scintillation screen combined with a digital video camera. Characterization of the scanned fluence maps was performed with a software analysis tool.

Results:

The resulting measurements and analysis indicated that the two types of delivery systems performed within specification for those aspects investigated. The significant differences were observed between the two types of scanning systems where one type exhibits a smaller spot size and associated penumbra than the other. The differential is minimum at maximum energy and increases inversely with decreasing energy. Additionally, the large spot system showed an increase in dose precision to a static target with layer rescanning whereas the small spot system did not.

Conclusions:

The measured results from the two types of modulated scanning types of system were consistent with their designs under the conditions tested. The most significant difference between the types of system was their proton spot size and associated resolution, factors of magnetic optics, and vacuum length. The need and benefit of mutielement detectors and high‐resolution sensors was also shown. The use of a fluence map analytical software tool was particularly effective in characterizing the dynamic proton energy‐layer scanning.
Magnetic tracking for TomoTherapy systems: Gradiometer based methods to filter eddy‐current magnetic fields
Authors: McGary John E. , Xiong Zubiao , Chen Ji
Published: June 2013

Purpose:

TomoTherapy systems lack real‐time, tumor tracking. A possible solution is to use electromagnetic markers; however, eddy‐current magnetic fields generated in response to a magnetic source can be comparable to the signal, thus degrading the localization accuracy. Therefore, the tracking system must be designed to account for the eddy fields created along the inner bore conducting surfaces. The aim of this work is to investigate localization accuracy using magnetic field gradients to determine feasibility toward TomoTherapy applications.

Methods:

Electromagnetic models are used to simulate magnetic fields created by a source and its simultaneous generation of eddy currents within a conducting cylinder. The source position is calculated using a least‐squares fit of simulated sensor data using the dipole equation as the model equation. To account for field gradients across the sensor area (∼25 cm2), an iterative method is used to estimate the magnetic field at the sensor center. Spatial gradients are calculated with two arrays of uniaxial, paired sensors that form a gradiometer array, where the sensors are considered ideal.

Results:

Experimental measurements of magnetic fields within the TomoTherapy bore are shown to be 1%–10% less than calculated with the electromagnetic model. Localization results using a 5 × 5 array of gradiometers are, in general, 2–4 times more accurate than a planar array of sensors, depending on the solenoid orientation and position. Simulation results show that the localization accuracy using a gradiometer array is within 1.3 mm over a distance of 20 cm from the array plane. In comparison, localization errors using single array are within 5 mm.

Conclusions:

The results indicate that the gradiometer method merits further studies and work due to the accuracy achieved with ideal sensors. Future studies should include realistic sensor models and extensive numerical studies to estimate the expected magnetic tracking accuracy within a TomoTherapy system before proceeding with prototype development.
Reverberation-based urban street sound level prediction
Authors: Thomas Pieter , Van Renterghem Timothy , De Boeck Ellen , Dragonetti Laurent , Botteldooren Dick
Published: June 2013

Street reverberation can strongly increase sound pressure levels in urban streets. In noise mapping models on the other hand, including a sufficient number of reflections is computationally very costly. A simple regression model is developed in this study, based on typical street width and façade height or façade roughness in old city centers of many European cities. This model is based on measurements with a mobile setup in 99 streets in the city of Ghent, Belgium, representative for common European city morphology. The reflection ratio (RR) is used as a parameter to determine the energy contained in the reverberation part of the sound field. The model has been successfully validated by detailed measurements at different source-receiver distances in an urban street canyon.
Non-intrusive planar velocity-based nearfield acoustic holography in moving fluid medium
Authors: Parisot-Dupuis Hélène , Simon Frank , Piot Estelle , Micheli Francis
Published: June 2013

Nearfield Acoustic Holography (NAH) is a powerful acoustic imaging method, but its application in aeronautics can be limited by intrusive measurements of acoustic field. In this paper, a moving fluid medium NAH procedure using non-intrusive velocity measurements is proposed. This method is based on convective Kirchhoff–Helmholtz integral formula. Convective equations and convective Green's function are used to derive convective real-space propagators including airflow effects. Discrete Fourier transforms of these propagators allow the assessment of acoustic fields from acoustic pressure or normal acoustic velocity measurements. As the aim is to derive an in-flow velocity-based NAH method, this study is especially focused on real convective velocity-to-pressure propagator. In order to validate this procedure, simulations in the case of monopole sources radiating in various uniform subsonic flows have been performed. NAH provides very favorable results when compared to the simulated fields. A comparison of results obtained by the real propagator and those obtained by the wave number–frequency-domain one developed by Kwon et al. [J. Acoust. Soc. Am. 128(4), 1823–1832 (2010)] shows the interest of using the real-form in the case of pressure backward propagation from velocity measurements. The efficiency of the developed procedure is confirmed by a wind tunnel campaign with a flush-mounted loudspeaker and non-intrusive Laser Doppler Velocimetry velocity measurements.
Effects of mean flow on transmission loss of orthogonally rib-stiffened aeroelastic plates
Authors: Xin F. X. , Lu T. J.
Published: June 2013

This paper investigates the sound transmission loss (STL) of aeroelastic plates reinforced by two sets of orthogonal rib-stiffeners in the presence of external mean flow. Built upon the periodicity of the structure, a comprehensive theoretical model is developed by considering the convection effect of mean flow. The rib-stiffeners are modeled by employing the Bernoulli-Euler beam theory and the torsional wave equation. While the solution for the transmission loss of the structure based on plate displacement and acoustic pressures is given in the form of space-harmonic series, the corresponding coefficients are obtained from the solution of a system of linear equations derived from the plate-beam coupling vibration governing equation and Helmholtz equation. The model predictions are validated by comparing with existing theoretical and experimental results in the absence of mean flow. A parametric study is subsequently performed to quantify the effects of mean flow as well as structure geometrical parameters upon the transmission loss. It is demonstrated that the transmission loss of periodically rib-stiffened structure is increased significantly with increasing Mach number of mean flow over a wide frequency range. The STL value for the case of sound wave incident downstream is pronouncedly larger than that associated with sound wave incident upstream.
Reference-free damage detection, localization, and quantification in composites
Authors: Jin Lim Hyung , Sohn Hoon , Min Yeum Chul , Min Kim Ji
Published: June 2013

In this study, a reference-free damage characterization technique is developed not only to identify but also to locate and quantify damage in composite structures subject to varying temperature conditions. First, damage is characterized in terms of a damage index (m-value) defined as the ratio of damage size to the wavelength of the A0 mode within the damage. Then, a feasible solution space defining all possible combinations of the damage location and size are estimated without using any prior baseline data obtained from the pristine condition of a structure or different paths. When additional information such as the A0 mode group velocity within the pristine region of the structure becomes available, the estimates for the damage location and size are updated with better accuracy. The uniqueness of this study lies in that damage localization and quantification as well as identification are all performed without comparing current Lamb wave signals with the ones obtained from the pristine condition of the target structure, making the proposed technique more attractive for online monitoring. Numerical and experimental tests are presented to demonstrate the effectiveness of the proposed damage detection technique under varying temperature.
Age-related differences in the sequential organization of speech sounds
Authors: Hutka Stefanie A. , Alain Claude , Binns Malcolm A. , Bidelman Gavin M.
Published: June 2013

This study investigated the effects of age on listeners' tendency to group speech tokens into one or two auditory streams. Younger and older adults were presented with sequences of four vowel sounds, which were arranged according to the proximity of first-formant frequencies between adjacent vowels. In Experiment 1, participants were less accurate in identifying the order of the four vowels and more likely to report hearing two streams when the first-formant alternated between low and high frequency and the overall difference between adjacent vowels was large. This effect of first-formant continuity on temporal order judgments and probability of hearing two streams was higher in younger than in older adults. In Experiment 2, participants indicated whether there was rhythm irregularity in an otherwise isochronous sequence of four vowels. Young adults' thresholds were lower when successive first-formants ascended or descended monotonically (condition promoting integration) than when they alternated discontinuously (condition promoting streaming). This effect was not observed in older adults whose thresholds were comparable for both types of vowel sequences. These two experiments provide converging evidence for an age-related deficit in exploiting first-formant information between consecutive vowels, which appear to impede older adults' ability to sequentially group speech sounds over time.
Estimating peripheral gain and compression using fixed-duration masking curves
Authors: Yasin Ifat , Drga Vit , Plack Christopher J.
Published: June 2013

Estimates of human basilar membrane gain and compression obtained using temporal masking curve (TMC) and additivity of forward masking (AFM) methods with long-duration maskers or long masker-signal silent intervals may be affected by olivocochlear efferent activation, which reduces basilar membrane gain. The present study introduces a fixed-duration masking curve (FDMC) method, which involves a comparison of off- and on-frequency forward masker levels at threshold as a function of masker and signal duration, with the total masker-signal duration fixed at 25 ms to minimize efferent effects. Gain and compression estimates from the FDMC technique were compared with those from TMC (104-ms maskers) and AFM (10- and 200-ms maskers) methods. Compression estimates over an input-masker range of 40–60 dB sound pressure level were similar for the four methods. Maximum compression occurred at a lower input level for the FDMC compared to the TMC method. Estimates of gain were similar for TMC and FDMC methods. The FDMC method may provide a more reliable estimate of BM gain and compression in the absence of efferent activation and could be a useful method for estimating effects of efferent activity when used with a precursor sound (to trigger efferent activation), presented prior to the combined masker-signal stimulus.
The attenuation of sound by turbulence in internal flows
Authors: Weng Chenyang , Boij Susann , Hanifi Ardeshir
Published: June 2013

The attenuation of sound waves due to interaction with low Mach number turbulent boundary layers in internal flows (channel or pipe flow) is examined. Dynamic equations for the turbulent Reynolds stress on the sound wave are derived, and the analytical solution to the equation provides a frequency dependent eddy viscosity model. This model is used to predict the attenuation of sound propagating in fully developed turbulent pipe flow. The predictions are shown to compare well with the experimental data. The proposed dynamic equation shows that the turbulence behaves like a viscoelastic fluid in the interaction process, and that the ratio of turbulent relaxation time near the wall and the sound wave period is the parameter that controls the characteristics of the attenuation induced by the turbulent flow.
A theoretical investigation of photoacoustic contrast agents
Authors: Firouzi K. , Stride E. , Saffari N.
Published: June 2013

Photoacoustic imaging offers significant potential as a biomedical imaging modality. For some applications, however, there is a need for contrast enhancement. In this paper, a theoretical comparison is presented of the efficacy of three different designs for photoacoustic contrast agents (PACAs), specifically, a droplet of dye, a bubble filled with gas coated by a dye loaded shell, and a droplet of volatile dye. For each case, the governing equations describing the dynamics of a single PACA in a homogenous incompressible fluid are derived. The coupled sets of equations describing the bubble oscillation and resulting radiated pressure, the photo-acoustic energy equation, and the equation of state are then solved numerically. The numerical results predict a stronger radiated acoustic signal for the same optical source energy density in the case of the volatile dye droplet by a factor of up to two orders of magnitude compared with the other two types of agent.
The role of diffusive architectural surfaces on auditory spatial discrimination in performance venues
Authors: Robinson Philip W. , Pätynen Jukka , Lokki Tapio , Suk Jang Hyung , Yong Jeon Jin , Xiang Ning
Published: June 2013

In musical or theatrical performance, some venues allow listeners to individually localize and segregate individual performers, while others produce a well blended ensemble sound. The room acoustic conditions that make this possible, and the psycho-acoustic effects at work are not fully understood. This research utilizes auralizations from measured and simulated performance venues to investigate spatial discrimination of multiple acoustic sources in rooms. Signals were generated from measurements taken in a small theater, and listeners in the audience area were asked to distinguish pairs of speech sources on stage with various spatial separations. This experiment was repeated with the proscenium splay walls treated to be flat, diffusive, or absorptive. Similar experiments were conducted in a simulated hall, utilizing 11 early reflections with various characteristics, and measured late reverberation. The experiments reveal that discriminating the lateral arrangement of two sources is possible at narrower separation angles when reflections come from flat or absorptive rather than diffusive surfaces.
Finite element computation of elliptical vocal tract impedances using the two-microphone transfer function method
Authors: Arnela Marc , Guasch Oriol
Published: June 2013

A two-microphone transfer function (TMTF) method is adapted to a numerical framework to compute the radiation and input impedances of three-dimensional vocal tracts of elliptical cross-section. In its simplest version, the TMTF method only requires measuring the acoustic pressure at two points in an impedance duct and the postprocessing of the corresponding transfer function. However, some considerations are to be taken into account when using the TMTF method in the numerical context, which constitute the main objective of this paper. In particular, the importance of including absorption at the impedance duct walls to avoid lengthy numerical simulations is discussed and analytical complex axial wave numbers for elliptical ducts are derived for this purpose. It is also shown how the direct impedance of plane wave propagation can be computed beyond the TMTF maximum threshold frequency by appropriate location of the virtual microphones. Virtual microphone spacing is also discussed on the basis of the so-called singularity factor. Numerical examples include the computation of the radiation impedance of vowels /a/, /i/, and /u/ and the input impedance of vowel /a/, for simplified vocal tracts of circular and elliptical cross-sections.
Efficacy of spatial averaging of infrasonic pressure in varying wind speeds
Authors: DeWolf Scott , Walker Kristoffer T. , Zumberge Mark A. , Denis Stephane
Published: June 2013

Wind noise reduction (WNR) is important in the measurement of infrasound. Spatial averaging theory led to the development of rosette pipe arrays. The efficacy of rosettes decreases with increasing wind speed and only provides a maximum of ∼20 dB WNR due to a maximum size limitation. An Optical Fiber Infrasound Sensor (OFIS) reduces wind noise by instantaneously averaging infrasound along the sensor's length. In this study two experiments quantify the WNR achieved by rosettes and OFISs of various sizes and configurations. Specifically, it is shown that the WNR for a circular OFIS 18 m in diameter is the same as a collocated 32-inlet pipe array of the same diameter. However, linear OFISs ranging in length from 30 to 270 m provide a WNR of up to ∼30 dB in winds up to 5 m/s. The measured WNR is a logarithmic function of the OFIS length and depends on the orientation of the OFIS with respect to wind direction. OFISs oriented parallel to the wind direction achieve ∼4 dB greater WNR than those oriented perpendicular to the wind. Analytical models for the rosette and OFIS are developed that predict the general observed relationships between wind noise reduction, frequency, and wind speed.
The role of first formant information in simulated electro-acoustic hearing
Authors: Verschuur Carl , Boland Conor , Frost Emily , Constable Jack
Published: June 2013

Cochlear implant (CI) recipients with residual hearing show improved performance with the addition of low-frequency acoustic stimulation (electro-acoustic stimulation, EAS). The present study sought to determine whether a synthesized first formant (F1) signal provided benefit to speech recognition in simulated EAS hearing and to compare such benefit with that from other low-frequency signals. A further aim was to determine if F1 amplitude or frequency was more important in determining benefit and if F1 benefit varied with formant bandwidth. In two experiments, sentence recordings from a male speaker were processed via a simulation of a partial insertion CI, and presented to normal hearing listeners in combination with various low-frequency signals, including a tone tracking fundamental frequency (F0), low-pass filtered speech, and signals based on F1 estimation. A simulated EAS benefit was found with F1 signals, and was similar to the benefit from F0 or low-pass filtered speech. The benefit did not differ significantly with the narrowing or widening of the F1 bandwidth. The benefit from low-frequency envelope signals was significantly less than the benefit from any low-frequency signal containing fine frequency information. Results indicate that F1 provides a benefit in simulated EAS hearing but low frequency envelope information is less important than low frequency fine structure in determining such benefit.
Use of mode subspace projections for depth discrimination with a horizontal line array: Theory and experimental results
Authors: Premus Vincent E. , Helfrick Mark N.
Published: June 2013

A solution to the problem of acoustic source depth discrimination in a downward refracting, shallow-water ocean waveguide is presented for the case of a horizontal line array at endfire. The approach exploits the phenomenon of mode trapping, wherein a shallow acoustic source cannot excite the lowest order waveguide modes due to its evanescent amplitude dependence near the surface. The important implication of this “trapping” behavior is that, given sufficient spatial aperture, it provides a mechanism for differentiating a shallow acoustic noise source from one at depth. The method does not require array cant, or physical vertical aperture of any kind, but instead relies only on the sensitivity of a line array at endfire to differences in horizontal wave number to resolve low and high order mode subspace excitations. The only inputs to the algorithm are an approximate sound speed profile, water depth, and bottom type. The theoretical basis for the test statistic is first reviewed, followed by discussion of key requirements, and illustration of the concept using results from a RAM PE simulation for a downward refracting environment. Finally, the algorithm is experimentally demonstrated using data from a bottom-mounted HLA deployed in the moderately cluttered continental shelf environment of the Florida Straits.
Rayleigh wave propagation method for the characterization of a thin layer of biomaterials
Authors: Kazemirad Siavash , Mongeau Luc
Published: June 2013

An experimental method based on Rayleigh wave propagation was developed for quantifying the frequency-dependent viscoelastic properties of a small volume of expensive biomaterials over a broad frequency range. Synthetic silicone rubber and gelatin materials were fabricated and tested to evaluate the proposed method. Planar harmonic Rayleigh waves at different frequencies, from 80 to 4000 Hz, were launched on the surface of a sample composed of a substrate with known material properties coated with a thin layer of the soft material to be characterized. A transfer function method was used to obtain the complex Rayleigh wavenumber. An inverse wave propagation problem was solved and a complex nonlinear dispersion equation was obtained. The complex shear and elastic moduli of the sample materials were then calculated through the numerical solution of the obtained dispersion equation using the measured wavenumbers. The results were in good agreement with those of a previous independent study. The proposed method was found to be reliable and cost effective for the measurement of viscoelastic properties of a thin layer of expensive biomaterials, such as phonosurgical biomaterials, over a wide frequency range.
Three-dimensional mapping of evolving internal waves during the Shallow Water 2006 experiment
Authors: Badiey Mohsen , Wan Lin , Song Aijun
Published: June 2013

Detailed knowledge of sound speed profiles and the sound speed profile's spatial and temporal variability resulting from internal waves (IWs) are indispensable to investigating significant acoustic field fluctuations in shallow water. A strategy to obtain a time-varying, three-dimensional (3D) IW temperature field is presented. It uses two types of simultaneous measurements: dense observations from a farm of thermistor strings and IW surface expressions from a ship-based radar. Using data from the Shallow Water 2006 experiment, the temperature field, over multiple kilometers in range, was reconstructed and, fed to a 3D acoustic model to demonstrate IW impacts on acoustic propagation.
Prosodic boundary information modulates phonetic categorization
Authors: Kim Sahyang , Cho Taehong
Published: June 2013

Categorical perception experiments were performed on an English /b-p/ voice onset time (VOT) continuum with native (American English) and non-native (Korean) listeners to examine whether and how phonetic categorization is modulated by prosodic boundary and language experience. Results demonstrated perceptual shifting according to prosodic boundary strength: A longer VOT was required to identify a sound as /p/ after an intonational phrase than a word boundary, regardless of the listeners' language experience. This suggests that segmental perception is modulated by the listeners' computation of an abstract prosodic structure reflected in phonetic cues of phrase-final lengthening and domain-initial strengthening, which are common across languages.
A phonetic explanation of pronunciation variant effects
Authors: Sumner Meghan
Published: June 2013

Effects of word-level phonetic variation on the recognition of words with different pronunciation variants (e.g., center produced with/(out) [t]) are investigated via the semantic- and pseudoword-priming paradigms. A bias favoring clearly articulated words with canonical variants ([nt]) is found. By reducing the bias, words with different variants show robust and equivalent lexical activation. The equivalence of different word forms highlights a snag for frequency-based theories of lexical access: How are words and word productions with vastly different frequencies recognized equally well by listeners? A process-based account is proposed, suggesting that careful speech induces bottom-up processing and casual speech induces top-down processing.
Experimental measurement of the acoustic sensitivity kernel
Authors: Roux Philippe , Marandet Christian , Nicolas Barbara , Kuperman W. A.
Published: June 2013

In the Born approximation, the acoustic scattering from a spherical obstacle of a size comparable to the acoustic wavelength can be evaluated in the framework of the sensitivity kernel approach, which describes the relationship between the pressure-field fluctuation and the position of a local change in the propagation medium. The spatial structure of the sensitivity kernel is here investigated through experimental observations made in a water tank at the ultrasonic scale and compared to an analytical model. The pattern of the sensitivity kernel is discussed in the case of a source-to-receiver wave field that includes a direct path and one surface reflection.
Amygdala-Dependent Fear Is Regulated by
Oprl1
in Mice and Humans with PTSD
Authors: Andero Raül , Brothers Shaun P. , Jovanovic Tanja , Chen Yen T. , Salah-Uddin Hasib , Cameron Michael , Bannister Thomas D. , Almli Lynn , Stevens Jennifer S. , Bradley Bekh , Binder Elisabeth B. , Wahlestedt Claes , Ressler Kerry J.
Published: June 2013

An agonist of the opioid receptor–like 1 protein may ameliorate the symptoms of posttraumatic stress disorder if given shortly after exposure to a traumatic event.
Preventing the Pain of PTSD
Authors: Seal Karen H. , Stein Murray B.
Published: June 2013

A selective opioid receptor agonist prevents fear memory consolidation in the amygdala in a mouse model of posttraumatic stress disorder (Andero
et al
., in this issue).
Novel Quorum-Sensing Peptides Mediating Interspecies Bacterial Cell Death
Authors: Kumar Sathish , Kolodkin-Gal Ilana , Engelberg-Kulka Hanna
Published: June 2013

Escherichia coli
mazEF
is a toxin-antitoxin stress-induced module mediating cell death. It requires the quorum-sensing signal (QS) “extracellular death factor” (EDF), the penta-peptide NNWNN (
Ec
EDF), enhancing the endoribonucleolytic activity of
E. coli
toxin MazF. Here we discovered that
E. coli mazEF
-mediated cell death could be triggered by QS peptides from the supernatants (SN) of the Gram-positive bacterium
Bacillus subtilis
and the Gram-negative bacterium
Pseudomonas aeruginosa
. In the SN of
B. subtilis
, we found one EDF, the hexapeptide RGQQNE, called
Bs
EDF. In the SN of
P. aeruginosa
, we found three EDFs: the nonapeptide INEQTVVTK, called
Pa
EDF-1, and two hexadecapeptides, VEVSDDGSGGNTSLSQ, called
Pa
EDF-2, and APKLSDGAAAGYVTKA, called
Pa
EDF-3. When added to a diluted
E. coli
cultures, each of these peptides acted as an interspecies EDF that triggered
mazEF
-mediated death. Furthermore, though their sequences are very different, each of these EDFs amplified the endoribonucleolytic activity of
E. coli
MazF, probably by interacting with different sites on
E. coli
MazF. Finally, we suggest that EDFs may become the basis for a new class of antibiotics that trigger death from outside the bacterial cells.

IMPORTANCE
Bacteria communicate with one another via quorum-sensing signal (QS) molecules. QS provides a mechanism for bacteria to monitor each other’s presence and to modulate gene expression in response to population density. Previously, we added
E. coli
EDF (
Ec
EDF), the peptide NNWNN, to this list of QS molecules. Here we extended the group of QS peptides to several additional different peptides. The new EDFs are produced by two other bacteria,
Bacillus subtilis
and
Pseudomonas aeruginosa
. Thus, in this study we established a “new family of EDFs.” This family provides the first example of quorum-sensing molecules participating in interspecies bacterial cell death. Furthermore, each of these peptides provides the basis of a new class of antibiotics triggering death by acting from outside the cell.
Human Cytomegalovirus (HCMV) Glycoprotein gB Promotes Virus Entry In
Trans
Acting as the Viral Fusion Protein Rather than as a Receptor-Binding Protein
Authors: Wille Paul T. , Wisner Todd W. , Ryckman Brent , Johnson David C.
Published: June 2013

Human cytomegalovirus (HCMV) glycoproteins gB and gH/gL are both necessary and sufficient for cell-cell fusion. However, it is not clear what roles these glycoproteins play in virus entry, whether acting directly in membrane fusion or in binding receptors. With other herpesviruses, it appears that gB is the fusion protein and is triggered by gH/gL, which, in some cases, binds receptors. However, for HCMV, there is published evidence that gB binds cellular ligands necessary to promote virus entry into or signaling of cells. Most mechanistic information on herpesvirus fusion proteins involves cell-cell fusion assays, which do not allow a determination of whether gB or gH/gL in the virion envelope must be oriented toward cellular membranes that contain receptors. Here, we showed that HCMV virions lacking gB were unable to enter normal cells but entered cells that expressed gB. Analyses of gB mutants lacking the cytoplasmic domain or with substitutions in putative “fusion loops” provided evidence that gB fusion activity was required for this “entry in
trans
.” In gB-mediated entry in
trans
, gB is oriented toward the virion envelope that apparently lacks receptors, arguing against an essential role for gB in binding receptors or signaling molecules. In contrast, particles lacking gH/gL did not enter cells expressing gH/gL, apparently because gH/gL must be oriented toward cellular membranes (which have receptors). Coupled with our previous interference studies, in which gH/gL expressed in cells blocked HCMV entry, our findings here support the hypothesis that HCMV gH/gL binds cellular receptors before triggering gB, which acts as the fusion protein.

IMPORTANCE
Human cytomegalovirus (HCMV) produces major disease in neonates and immunosuppressed transplant patients. As with other herpesviruses, HCMV requires two membrane glycoproteins, gB and gH/gL, to enter host cells. However, it has not been clear how gB and gH/gL function in two steps of the HCMV entry pathway, i.e., (i) binding of cellular receptors and (ii) fusion of the virion envelope with cellular membranes. There are studies that suggest that HCMV gB is required for receptor binding and other studies suggesting that gH/gL is the receptor binding protein and gB is the fusion protein. Here, we show that HCMV virions lacking gB can enter cells that express gB in cellular membranes. In contrast, virus particles lacking gH/gL could not enter cells expressing gH/gL. Our study supports the hypothesis that gB is the fusion protein and gH/gL acts upstream of gB to bind receptors and then activate gB for fusion.
Natural Genetic Variation of Xanthomonas campestris pv. campestris Pathogenicity onArabidopsisRevealed by Association and Reverse Genetics
Authors: Guy Endrick , Genissel Anne , Hajri Ahmed , Chabannes Matthieu , David Perrine , Carrere Sébastien , Lautier Martine , Roux Brice , Boureau Tristan , Arlat Matthieu , Poussier Stéphane , Noël Laurent D.
Published: June 2013

The pathogenic bacteriumXanthomonas campestrispv. campestris, the causal agent of black rot of Brassicaceae, manipulates the physiology and the innate immunity of its hosts. Association genetic and reverse-genetic analyses of a world panel of 45X. campestrispv. campestris strains were used to gain understanding of the genetic basis of the bacterium’s pathogenicity toArabidopsis thaliana. We found that the compositions of the minimal predicted type III secretome varied extensively, with 18 to 28 proteins per strain. There were clear differences in aggressiveness of thoseX. campestrispv. campestris strains on twoArabidopsisnatural accessions. We identified 3 effector genes (xopAC,xopJ5, andxopAL2) and 67 amplified fragment length polymorphism (AFLP) markers that were associated with variations in disease symptoms. The nature and distribution of the AFLP markers remain to be determined, but we observed a low linkage disequilibrium level between predicted effectors and other significant markers, suggesting that additional genetic factors make a meaningful contribution to pathogenicity. Mutagenesis of type III effectors inX. campestrispv. campestris confirmed thatxopACfunctions as both a virulence and an avirulence gene inArabidopsisand thatxopAMfunctions as a second avirulence gene on plants of the Col-0 ecotype. However, we did not detect the effect of any other effector in theX. campestrispv. campestris 8004 strain, likely due to other genetic background effects. These results highlight the complex genetic basis of pathogenicity at the pathovar level and encourage us to challenge the agronomical relevance of some virulence determinants identified solely in model strains.

IMPORTANCEThe identification and understanding of the genetic determinants of bacterial virulence are essential to be able to design efficient protection strategies for infected plants. The recent availability of genomic resources for a limited number of pathogen isolates and host genotypes has strongly biased our research toward genotype-specific approaches. Indeed, these do not consider the natural variation in both pathogens and hosts, so their applied relevance should be challenged. In our study, we exploited the genetic diversity ofXanthomonas campestrispv. campestris, the causal agent of black rot on Brassicaceae (e.g., cabbage), to mine for pathogenicity determinants. This work evidenced the contribution of known and unknown loci to pathogenicity relevant at the pathovar level and identified these virulence determinants as prime targets for breeding resistance toX. campestrispv. campestris in Brassicaceae.
The relationship between informal caregiving and mortality: an analysis using the ONS Longitudinal Study of England and Wales
Authors: Ramsay Susan , Grundy Emily , O'Reilly Dermot
Published: June 2013

Background

Many studies have suggested that caregiving has a detrimental impact on health. However, these conclusions are challenged by research which finds evidence of a comparative survivorship advantage, as well as work which controls for group differences in the demand for care.

Methods

We use a large record linkage study of England and Wales to investigate the mortality risks of carers identified in the 2001 Census. The analysis focuses on individuals aged 35–74 living with others in private households and a distinction is made between those providing 1–19 and 20 or more hours of care per week. Logit models identify differences in carers’ health at baseline and postcensal survival is analysed using Cox proportional hazards models.

Results

12.2% of study members reported providing 1–19 h of care and 5.4% reported providing 20 or more hours. While carers were significantly more likely to report poorer health at baseline, survival analyses suggested that they were at a significantly lower risk of dying. This comparative advantage also held when the analyses were restricted to individuals living with at least one person with poor health.

Conclusions

The comparative mortality advantage revealed in this analysis challenges common characterisations of carers' health and draws attention to important differences in the way carers are defined in existing analyses. The survival results are consistent with work using similar data for Northern Ireland. However, the study also affords more uniform conclusions about carers’ baseline health and this provides grounds for questioning existing hypotheses about the reasons for this advantage.
Gunshot induced indirect femoral fracture: mechanism of injury and fracture morphology
Authors: Kieser David C , Carr D J , Leclair S C J , Horsfall I , Theis J C , Swain M V , Kieser J A
Published: June 2013

Introduction

Indirect ballistic fractures occur when a projectile passes close to, but not contacting, the bone. The mechanism of how these fractures occur is not yet proven, but recently the acoustic shockwave has been excluded as a cause. The objective of this study is to determine whether the expanding temporary cavity, the collapse of this cavity or its oscillation causes these fractures. In addition, we describe the fracture morphology and biomechanical causes of this injury.

Method

40 fresh deer femora were strain gauged and embedded in ballistic gelatin before being shot with four different projectiles with varying distances off the bone. Pressure recordings, chronographs and radar allowed assessment of local pressures and energy transfer. High-speed video allowed the temporal relationship between the temporary cavity and fracture formation to be analysed, while sample dissection allowed the fracture morphology to be described.

Results

The fractures produced were consistently wedge-shaped and caused by the expansion of the temporary cavity, flexing the bone beyond its yield point, causing tension failure on the cortex opposite the expanding temporary cavity and a compression wedge on the side of the cavity. Local pressure was not predictive of fracture formation but the energy transfer to the gelatin block was predictive.

Conclusions

Indirect fractures are caused by the expansion of the temporary cavity and relate to the proximity of this cavity to the bone. Fractures occur from flexion of the bone and classically display wedge-shaped fracture patterns with the apex of the wedge pointing away from the expanding cavity.
Tandem symptomatic internal carotid artery and persistent hypoglossal artery stenosis treated by endovascular stenting and flow reversal
Authors: Eller Jorge L , Jahshan Shady , Dumont Travis M , Kan Peter , Siddiqui Adnan H
Published: June 2013

Persistence of the hypoglossal artery into adulthood is a rare vascular anomaly and, when present, provides the predominant vascular supply to the posterior circulation. We describe a case of vertebrobasilar insufficiency associated with severe high-grade stenosis of the persistent hypoglossal artery and tandem stenosis of the proximal ipsilateral internal carotid artery, treated by an endovascular approach. The unique anatomical and technical challenges associated with this case are reviewed in detail.
Effects of urbanization on small-mammal communities and the population structure of synurbic species: an example of a medium-sized city
Authors: Łopucki Rafał , Mróz Iwona , Berliński Łukasz , Burzych Marzena
Published: June 2013

Theories concerning the impact of urbanization on ground-dwelling mammals are mainly based on large-city studies. We investigated whether the negative effects of urbanization are evident in smaller urban areas, where green areas are usually less isolated from their natural surroundings. Livetrapping of small mammals (Rodentia and Soricomorpha) was conducted between 2007 and 2010 in 15 patches within the city of Lublin (Poland) (147.5 km2, population 354 000) and 15 patches in its agricultural surroundings. A decline in species richness and diversity along an urbanization gradient and an increase in the abundance of species best adapted to the city environment (synurbic species) were observed. The main factors influencing ground-dwelling mammals was isolation of green patches, while the management type of green areas had no significant effect. The genus Apodemus Kaup, 1829, particularly the striped field mouse (Apodemus agrarius (Pallas, 1771)), was the most urban biased. Within the city, A. agrarius alters its habitat preferences and life-history parameters (body mass, seasonal fluctuations, winter survival). Understanding the factors influencing ground-dwelling mammals in medium-sized cities will enable measures to be implemented that could reduce the negative effects of urbanization during urban expansion.
SUSY INTO DARKNESS: HEAVY SCALARS IN THE CMSSM
Authors: MAYES VAN E.
Published: June 2013

A survey of the mSUGRA/CMSSM parameter space is presented. The viable regions of the parameter space which satisfy standard experimental constraints are identified and discussed. These constraints include a 124–127 GeV mass for the lightest CP-even Higgs and the correct relic density for cold dark matter. The superpartner spectra corresponding to these regions fall within the well-known hyperbolic branch and are found to possess sub-TeV neutralinos and charginos, with mixed Bino/Higgsino LSP's with 200–800 GeV masses. In addition, the models possess ~3–4 TeV gluino masses and heavy squarks and sleptons with masses [Formula: see text]. Spectra with a Higgs mass mh≅125 GeV and a relic density 0.105 ≤ Ωχ0h2≤ 0.123 are found to require EWFT at around the one-percent level, while those spectra with a much lower relic density require EWFT of only a few percent. Moreover, the spin-independent neutralino–proton direct detection cross-sections are found to be below or within the XENON100 2σ limit and should be experimentally accessible now or in the near future. Finally, it is pointed out that the supersymmetry breaking soft terms corresponding to these regions of the mSUGRA/CMSSM parameter space (m0∝ m1/2with [Formula: see text] and A0= -m1/2) may be obtained from general flux-induced soft terms in Type IIB flux compactifications with D3 branes.